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linux-stable/tools/lib/bpf/libbpf.c
Toke Høiland-Jørgensen 4f33ddb4e3 libbpf: Propagate EPERM to caller on program load 
When loading an eBPF program, libbpf overrides the return code for EPERM
errors instead of returning it to the caller. This makes it hard to figure
out what went wrong on load.

In particular, EPERM is returned when the system rlimit is too low to lock
the memory required for the BPF program. Previously, this was somewhat
obscured because the rlimit error would be hit on map creation (which does
return it correctly). However, since maps can now be reused, object load
can proceed all the way to loading programs without hitting the error;
propagating it even in this case makes it possible for the caller to react
appropriately (and, e.g., attempt to raise the rlimit before retrying).

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/157333184946.88376.11768171652794234561.stgit@toke.dk
2019-11-10 19:26:30 -08:00

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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* Common eBPF ELF object loading operations.
*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
* Copyright (C) 2017 Nicira, Inc.
* Copyright (C) 2019 Isovalent, Inc.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <libgen.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <endian.h>
#include <fcntl.h>
#include <errno.h>
#include <asm/unistd.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/list.h>
#include <linux/limits.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <linux/version.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/utsname.h>
#include <tools/libc_compat.h>
#include <libelf.h>
#include <gelf.h>
#include "libbpf.h"
#include "bpf.h"
#include "btf.h"
#include "str_error.h"
#include "libbpf_internal.h"
#include "hashmap.h"
#ifndef EM_BPF
#define EM_BPF 247
#endif
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
/* vsprintf() in __base_pr() uses nonliteral format string. It may break
* compilation if user enables corresponding warning. Disable it explicitly.
*/
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#define __printf(a, b) __attribute__((format(printf, a, b)))
static int __base_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
if (level == LIBBPF_DEBUG)
return 0;
return vfprintf(stderr, format, args);
}
static libbpf_print_fn_t __libbpf_pr = __base_pr;
libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
{
libbpf_print_fn_t old_print_fn = __libbpf_pr;
__libbpf_pr = fn;
return old_print_fn;
}
__printf(2, 3)
void libbpf_print(enum libbpf_print_level level, const char *format, ...)
{
va_list args;
if (!__libbpf_pr)
return;
va_start(args, format);
__libbpf_pr(level, format, args);
va_end(args);
}
#define STRERR_BUFSIZE 128
#define CHECK_ERR(action, err, out) do { \
err = action; \
if (err) \
goto out; \
} while(0)
/* Copied from tools/perf/util/util.h */
#ifndef zfree
# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
#endif
#ifndef zclose
# define zclose(fd) ({ \
int ___err = 0; \
if ((fd) >= 0) \
___err = close((fd)); \
fd = -1; \
___err; })
#endif
#ifdef HAVE_LIBELF_MMAP_SUPPORT
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
#else
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
#endif
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
struct bpf_capabilities {
/* v4.14: kernel support for program & map names. */
__u32 name:1;
/* v5.2: kernel support for global data sections. */
__u32 global_data:1;
/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
__u32 btf_func:1;
/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
__u32 btf_datasec:1;
};
/*
* bpf_prog should be a better name but it has been used in
* linux/filter.h.
*/
struct bpf_program {
/* Index in elf obj file, for relocation use. */
int idx;
char *name;
int prog_ifindex;
char *section_name;
/* section_name with / replaced by _; makes recursive pinning
* in bpf_object__pin_programs easier
*/
char *pin_name;
struct bpf_insn *insns;
size_t insns_cnt, main_prog_cnt;
enum bpf_prog_type type;
struct reloc_desc {
enum {
RELO_LD64,
RELO_CALL,
RELO_DATA,
} type;
int insn_idx;
union {
int map_idx;
int text_off;
};
} *reloc_desc;
int nr_reloc;
int log_level;
struct {
int nr;
int *fds;
} instances;
bpf_program_prep_t preprocessor;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
enum bpf_attach_type expected_attach_type;
__u32 attach_btf_id;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
struct bpf_capabilities *caps;
void *line_info;
__u32 line_info_rec_size;
__u32 line_info_cnt;
__u32 prog_flags;
};
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
LIBBPF_MAP_DATA,
LIBBPF_MAP_BSS,
LIBBPF_MAP_RODATA,
};
static const char * const libbpf_type_to_btf_name[] = {
[LIBBPF_MAP_DATA] = ".data",
[LIBBPF_MAP_BSS] = ".bss",
[LIBBPF_MAP_RODATA] = ".rodata",
};
struct bpf_map {
int fd;
char *name;
int sec_idx;
size_t sec_offset;
int map_ifindex;
int inner_map_fd;
struct bpf_map_def def;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
char *pin_path;
bool pinned;
bool reused;
};
struct bpf_secdata {
void *rodata;
void *data;
};
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char name[BPF_OBJ_NAME_LEN];
char license[64];
__u32 kern_version;
struct bpf_program *programs;
size_t nr_programs;
struct bpf_map *maps;
size_t nr_maps;
size_t maps_cap;
struct bpf_secdata sections;
bool loaded;
bool has_pseudo_calls;
bool relaxed_core_relocs;
/*
* Information when doing elf related work. Only valid if fd
* is valid.
*/
struct {
int fd;
const void *obj_buf;
size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
Elf_Data *data;
Elf_Data *rodata;
Elf_Data *bss;
size_t strtabidx;
struct {
GElf_Shdr shdr;
Elf_Data *data;
} *reloc;
int nr_reloc;
int maps_shndx;
int btf_maps_shndx;
int text_shndx;
int data_shndx;
int rodata_shndx;
int bss_shndx;
} efile;
/*
* All loaded bpf_object is linked in a list, which is
* hidden to caller. bpf_objects__<func> handlers deal with
* all objects.
*/
struct list_head list;
struct btf *btf;
struct btf_ext *btf_ext;
void *priv;
bpf_object_clear_priv_t clear_priv;
struct bpf_capabilities caps;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
void bpf_program__unload(struct bpf_program *prog)
{
int i;
if (!prog)
return;
/*
* If the object is opened but the program was never loaded,
* it is possible that prog->instances.nr == -1.
*/
if (prog->instances.nr > 0) {
for (i = 0; i < prog->instances.nr; i++)
zclose(prog->instances.fds[i]);
} else if (prog->instances.nr != -1) {
pr_warn("Internal error: instances.nr is %d\n",
prog->instances.nr);
}
prog->instances.nr = -1;
zfree(&prog->instances.fds);
zfree(&prog->func_info);
zfree(&prog->line_info);
}
static void bpf_program__exit(struct bpf_program *prog)
{
if (!prog)
return;
if (prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = NULL;
prog->clear_priv = NULL;
bpf_program__unload(prog);
zfree(&prog->name);
zfree(&prog->section_name);
zfree(&prog->pin_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
prog->insns_cnt = 0;
prog->idx = -1;
}
static char *__bpf_program__pin_name(struct bpf_program *prog)
{
char *name, *p;
name = p = strdup(prog->section_name);
while ((p = strchr(p, '/')))
*p = '_';
return name;
}
static int
bpf_program__init(void *data, size_t size, char *section_name, int idx,
struct bpf_program *prog)
{
const size_t bpf_insn_sz = sizeof(struct bpf_insn);
if (size == 0 || size % bpf_insn_sz) {
pr_warn("corrupted section '%s', size: %zu\n",
section_name, size);
return -EINVAL;
}
memset(prog, 0, sizeof(*prog));
prog->section_name = strdup(section_name);
if (!prog->section_name) {
pr_warn("failed to alloc name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->pin_name = __bpf_program__pin_name(prog);
if (!prog->pin_name) {
pr_warn("failed to alloc pin name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->insns = malloc(size);
if (!prog->insns) {
pr_warn("failed to alloc insns for prog under section %s\n",
section_name);
goto errout;
}
prog->insns_cnt = size / bpf_insn_sz;
memcpy(prog->insns, data, size);
prog->idx = idx;
prog->instances.fds = NULL;
prog->instances.nr = -1;
prog->type = BPF_PROG_TYPE_UNSPEC;
return 0;
errout:
bpf_program__exit(prog);
return -ENOMEM;
}
static int
bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
char *section_name, int idx)
{
struct bpf_program prog, *progs;
int nr_progs, err;
err = bpf_program__init(data, size, section_name, idx, &prog);
if (err)
return err;
prog.caps = &obj->caps;
progs = obj->programs;
nr_progs = obj->nr_programs;
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
if (!progs) {
/*
* In this case the original obj->programs
* is still valid, so don't need special treat for
* bpf_close_object().
*/
pr_warn("failed to alloc a new program under section '%s'\n",
section_name);
bpf_program__exit(&prog);
return -ENOMEM;
}
pr_debug("found program %s\n", prog.section_name);
obj->programs = progs;
obj->nr_programs = nr_progs + 1;
prog.obj = obj;
progs[nr_progs] = prog;
return 0;
}
static int
bpf_object__init_prog_names(struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
struct bpf_program *prog;
size_t pi, si;
for (pi = 0; pi < obj->nr_programs; pi++) {
const char *name = NULL;
prog = &obj->programs[pi];
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (sym.st_shndx != prog->idx)
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
continue;
name = elf_strptr(obj->efile.elf,
obj->efile.strtabidx,
sym.st_name);
if (!name) {
pr_warn("failed to get sym name string for prog %s\n",
prog->section_name);
return -LIBBPF_ERRNO__LIBELF;
}
}
if (!name && prog->idx == obj->efile.text_shndx)
name = ".text";
if (!name) {
pr_warn("failed to find sym for prog %s\n",
prog->section_name);
return -EINVAL;
}
prog->name = strdup(name);
if (!prog->name) {
pr_warn("failed to allocate memory for prog sym %s\n",
name);
return -ENOMEM;
}
}
return 0;
}
static __u32 get_kernel_version(void)
{
__u32 major, minor, patch;
struct utsname info;
uname(&info);
if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
return 0;
return KERNEL_VERSION(major, minor, patch);
}
static struct bpf_object *bpf_object__new(const char *path,
const void *obj_buf,
size_t obj_buf_sz,
const char *obj_name)
{
struct bpf_object *obj;
char *end;
obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
if (!obj) {
pr_warn("alloc memory failed for %s\n", path);
return ERR_PTR(-ENOMEM);
}
strcpy(obj->path, path);
if (obj_name) {
strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
obj->name[sizeof(obj->name) - 1] = 0;
} else {
/* Using basename() GNU version which doesn't modify arg. */
strncpy(obj->name, basename((void *)path),
sizeof(obj->name) - 1);
end = strchr(obj->name, '.');
if (end)
*end = 0;
}
obj->efile.fd = -1;
/*
* Caller of this function should also call
* bpf_object__elf_finish() after data collection to return
* obj_buf to user. If not, we should duplicate the buffer to
* avoid user freeing them before elf finish.
*/
obj->efile.obj_buf = obj_buf;
obj->efile.obj_buf_sz = obj_buf_sz;
obj->efile.maps_shndx = -1;
obj->efile.btf_maps_shndx = -1;
obj->efile.data_shndx = -1;
obj->efile.rodata_shndx = -1;
obj->efile.bss_shndx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
INIT_LIST_HEAD(&obj->list);
list_add(&obj->list, &bpf_objects_list);
return obj;
}
static void bpf_object__elf_finish(struct bpf_object *obj)
{
if (!obj_elf_valid(obj))
return;
if (obj->efile.elf) {
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
}
obj->efile.symbols = NULL;
obj->efile.data = NULL;
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
zfree(&obj->efile.reloc);
obj->efile.nr_reloc = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
}
static int bpf_object__elf_init(struct bpf_object *obj)
{
int err = 0;
GElf_Ehdr *ep;
if (obj_elf_valid(obj)) {
pr_warn("elf init: internal error\n");
return -LIBBPF_ERRNO__LIBELF;
}
if (obj->efile.obj_buf_sz > 0) {
/*
* obj_buf should have been validated by
* bpf_object__open_buffer().
*/
obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
obj->efile.obj_buf_sz);
} else {
obj->efile.fd = open(obj->path, O_RDONLY);
if (obj->efile.fd < 0) {
char errmsg[STRERR_BUFSIZE], *cp;
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to open %s: %s\n", obj->path, cp);
return err;
}
obj->efile.elf = elf_begin(obj->efile.fd,
LIBBPF_ELF_C_READ_MMAP, NULL);
}
if (!obj->efile.elf) {
pr_warn("failed to open %s as ELF file\n", obj->path);
err = -LIBBPF_ERRNO__LIBELF;
goto errout;
}
if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
pr_warn("failed to get EHDR from %s\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
ep = &obj->efile.ehdr;
/* Old LLVM set e_machine to EM_NONE */
if (ep->e_type != ET_REL ||
(ep->e_machine && ep->e_machine != EM_BPF)) {
pr_warn("%s is not an eBPF object file\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
return 0;
errout:
bpf_object__elf_finish(obj);
return err;
}
static int bpf_object__check_endianness(struct bpf_object *obj)
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return 0;
#elif __BYTE_ORDER == __BIG_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
return 0;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
pr_warn("endianness mismatch.\n");
return -LIBBPF_ERRNO__ENDIAN;
}
static int
bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
{
memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
pr_debug("license of %s is %s\n", obj->path, obj->license);
return 0;
}
static int
bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
{
__u32 kver;
if (size != sizeof(kver)) {
pr_warn("invalid kver section in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
memcpy(&kver, data, sizeof(kver));
obj->kern_version = kver;
pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
return 0;
}
static int compare_bpf_map(const void *_a, const void *_b)
{
const struct bpf_map *a = _a;
const struct bpf_map *b = _b;
if (a->sec_idx != b->sec_idx)
return a->sec_idx - b->sec_idx;
return a->sec_offset - b->sec_offset;
}
static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
{
if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
type == BPF_MAP_TYPE_HASH_OF_MAPS)
return true;
return false;
}
static int bpf_object_search_section_size(const struct bpf_object *obj,
const char *name, size_t *d_size)
{
const GElf_Ehdr *ep = &obj->efile.ehdr;
Elf *elf = obj->efile.elf;
Elf_Scn *scn = NULL;
int idx = 0;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
const char *sec_name;
Elf_Data *data;
GElf_Shdr sh;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -EIO;
}
sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!sec_name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -EIO;
}
if (strcmp(name, sec_name))
continue;
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
return -EIO;
}
*d_size = data->d_size;
return 0;
}
return -ENOENT;
}
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size)
{
int ret = -ENOENT;
size_t d_size;
*size = 0;
if (!name) {
return -EINVAL;
} else if (!strcmp(name, ".data")) {
if (obj->efile.data)
*size = obj->efile.data->d_size;
} else if (!strcmp(name, ".bss")) {
if (obj->efile.bss)
*size = obj->efile.bss->d_size;
} else if (!strcmp(name, ".rodata")) {
if (obj->efile.rodata)
*size = obj->efile.rodata->d_size;
} else {
ret = bpf_object_search_section_size(obj, name, &d_size);
if (!ret)
*size = d_size;
}
return *size ? 0 : ret;
}
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off)
{
Elf_Data *symbols = obj->efile.symbols;
const char *sname;
size_t si;
if (!name || !off)
return -EINVAL;
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
continue;
sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!sname) {
pr_warn("failed to get sym name string for var %s\n",
name);
return -EIO;
}
if (strcmp(name, sname) == 0) {
*off = sym.st_value;
return 0;
}
}
return -ENOENT;
}
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
{
struct bpf_map *new_maps;
size_t new_cap;
int i;
if (obj->nr_maps < obj->maps_cap)
return &obj->maps[obj->nr_maps++];
new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
if (!new_maps) {
pr_warn("alloc maps for object failed\n");
return ERR_PTR(-ENOMEM);
}
obj->maps_cap = new_cap;
obj->maps = new_maps;
/* zero out new maps */
memset(obj->maps + obj->nr_maps, 0,
(obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
/*
* fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
* when failure (zclose won't close negative fd)).
*/
for (i = obj->nr_maps; i < obj->maps_cap; i++) {
obj->maps[i].fd = -1;
obj->maps[i].inner_map_fd = -1;
}
return &obj->maps[obj->nr_maps++];
}
static int
bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
int sec_idx, Elf_Data *data, void **data_buff)
{
char map_name[BPF_OBJ_NAME_LEN];
struct bpf_map_def *def;
struct bpf_map *map;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->libbpf_type = type;
map->sec_idx = sec_idx;
map->sec_offset = 0;
snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
libbpf_type_to_btf_name[type]);
map->name = strdup(map_name);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
def = &map->def;
def->type = BPF_MAP_TYPE_ARRAY;
def->key_size = sizeof(int);
def->value_size = data->d_size;
def->max_entries = 1;
def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0;
if (data_buff) {
*data_buff = malloc(data->d_size);
if (!*data_buff) {
zfree(&map->name);
pr_warn("failed to alloc map content buffer\n");
return -ENOMEM;
}
memcpy(*data_buff, data->d_buf, data->d_size);
}
pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
return 0;
}
static int bpf_object__init_global_data_maps(struct bpf_object *obj)
{
int err;
if (!obj->caps.global_data)
return 0;
/*
* Populate obj->maps with libbpf internal maps.
*/
if (obj->efile.data_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
obj->efile.data_shndx,
obj->efile.data,
&obj->sections.data);
if (err)
return err;
}
if (obj->efile.rodata_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
obj->efile.rodata_shndx,
obj->efile.rodata,
&obj->sections.rodata);
if (err)
return err;
}
if (obj->efile.bss_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
obj->efile.bss_shndx,
obj->efile.bss, NULL);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
{
Elf_Data *symbols = obj->efile.symbols;
int i, map_def_sz = 0, nr_maps = 0, nr_syms;
Elf_Data *data = NULL;
Elf_Scn *scn;
if (obj->efile.maps_shndx < 0)
return 0;
if (!symbols)
return -EINVAL;
scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
if (scn)
data = elf_getdata(scn, NULL);
if (!scn || !data) {
pr_warn("failed to get Elf_Data from map section %d\n",
obj->efile.maps_shndx);
return -EINVAL;
}
/*
* Count number of maps. Each map has a name.
* Array of maps is not supported: only the first element is
* considered.
*
* TODO: Detect array of map and report error.
*/
nr_syms = symbols->d_size / sizeof(GElf_Sym);
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
nr_maps++;
}
/* Assume equally sized map definitions */
pr_debug("maps in %s: %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
pr_warn("unable to determine map definition size "
"section %s, %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
return -EINVAL;
}
map_def_sz = data->d_size / nr_maps;
/* Fill obj->maps using data in "maps" section. */
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
const char *map_name;
struct bpf_map_def *def;
struct bpf_map *map;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!map_name) {
pr_warn("failed to get map #%d name sym string for obj %s\n",
i, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->sec_idx = sym.st_shndx;
map->sec_offset = sym.st_value;
pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
if (sym.st_value + map_def_sz > data->d_size) {
pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
obj->path, map_name);
return -EINVAL;
}
map->name = strdup(map_name);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
pr_debug("map %d is \"%s\"\n", i, map->name);
def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
/*
* If the definition of the map in the object file fits in
* bpf_map_def, copy it. Any extra fields in our version
* of bpf_map_def will default to zero as a result of the
* calloc above.
*/
if (map_def_sz <= sizeof(struct bpf_map_def)) {
memcpy(&map->def, def, map_def_sz);
} else {
/*
* Here the map structure being read is bigger than what
* we expect, truncate if the excess bits are all zero.
* If they are not zero, reject this map as
* incompatible.
*/
char *b;
for (b = ((char *)def) + sizeof(struct bpf_map_def);
b < ((char *)def) + map_def_sz; b++) {
if (*b != 0) {
pr_warn("maps section in %s: \"%s\" "
"has unrecognized, non-zero "
"options\n",
obj->path, map_name);
if (strict)
return -EINVAL;
}
}
memcpy(&map->def, def, sizeof(struct bpf_map_def));
}
}
return 0;
}
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t = btf__type_by_id(btf, id);
if (res_id)
*res_id = id;
while (btf_is_mod(t) || btf_is_typedef(t)) {
if (res_id)
*res_id = t->type;
t = btf__type_by_id(btf, t->type);
}
return t;
}
/*
* Fetch integer attribute of BTF map definition. Such attributes are
* represented using a pointer to an array, in which dimensionality of array
* encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
* encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
* type definition, while using only sizeof(void *) space in ELF data section.
*/
static bool get_map_field_int(const char *map_name, const struct btf *btf,
const struct btf_type *def,
const struct btf_member *m, __u32 *res) {
const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
const char *name = btf__name_by_offset(btf, m->name_off);
const struct btf_array *arr_info;
const struct btf_type *arr_t;
if (!btf_is_ptr(t)) {
pr_warn("map '%s': attr '%s': expected PTR, got %u.\n",
map_name, name, btf_kind(t));
return false;
}
arr_t = btf__type_by_id(btf, t->type);
if (!arr_t) {
pr_warn("map '%s': attr '%s': type [%u] not found.\n",
map_name, name, t->type);
return false;
}
if (!btf_is_array(arr_t)) {
pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n",
map_name, name, btf_kind(arr_t));
return false;
}
arr_info = btf_array(arr_t);
*res = arr_info->nelems;
return true;
}
static int build_map_pin_path(struct bpf_map *map, const char *path)
{
char buf[PATH_MAX];
int err, len;
if (!path)
path = "/sys/fs/bpf";
len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_map__set_pin_path(map, buf);
if (err)
return err;
return 0;
}
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
const Elf_Data *data, bool strict,
const char *pin_root_path)
{
const struct btf_type *var, *def, *t;
const struct btf_var_secinfo *vi;
const struct btf_var *var_extra;
const struct btf_member *m;
const char *map_name;
struct bpf_map *map;
int vlen, i;
vi = btf_var_secinfos(sec) + var_idx;
var = btf__type_by_id(obj->btf, vi->type);
var_extra = btf_var(var);
map_name = btf__name_by_offset(obj->btf, var->name_off);
vlen = btf_vlen(var);
if (map_name == NULL || map_name[0] == '\0') {
pr_warn("map #%d: empty name.\n", var_idx);
return -EINVAL;
}
if ((__u64)vi->offset + vi->size > data->d_size) {
pr_warn("map '%s' BTF data is corrupted.\n", map_name);
return -EINVAL;
}
if (!btf_is_var(var)) {
pr_warn("map '%s': unexpected var kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
var_extra->linkage != BTF_VAR_STATIC) {
pr_warn("map '%s': unsupported var linkage %u.\n",
map_name, var_extra->linkage);
return -EOPNOTSUPP;
}
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (!btf_is_struct(def)) {
pr_warn("map '%s': unexpected def kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (def->size > vi->size) {
pr_warn("map '%s': invalid def size.\n", map_name);
return -EINVAL;
}
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->name = strdup(map_name);
if (!map->name) {
pr_warn("map '%s': failed to alloc map name.\n", map_name);
return -ENOMEM;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->def.type = BPF_MAP_TYPE_UNSPEC;
map->sec_idx = sec_idx;
map->sec_offset = vi->offset;
pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("map '%s': invalid field #%d.\n", map_name, i);
return -EINVAL;
}
if (strcmp(name, "type") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.type))
return -EINVAL;
pr_debug("map '%s': found type = %u.\n",
map_name, map->def.type);
} else if (strcmp(name, "max_entries") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.max_entries))
return -EINVAL;
pr_debug("map '%s': found max_entries = %u.\n",
map_name, map->def.max_entries);
} else if (strcmp(name, "map_flags") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.map_flags))
return -EINVAL;
pr_debug("map '%s': found map_flags = %u.\n",
map_name, map->def.map_flags);
} else if (strcmp(name, "key_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, def, m,
&sz))
return -EINVAL;
pr_debug("map '%s': found key_size = %u.\n",
map_name, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %u.\n",
map_name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
} else if (strcmp(name, "key") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': key type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %lld.\n",
map_name, t->type, sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %lld.\n",
map_name, t->type, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %lld.\n",
map_name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
map->btf_key_type_id = t->type;
} else if (strcmp(name, "value_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, def, m,
&sz))
return -EINVAL;
pr_debug("map '%s': found value_size = %u.\n",
map_name, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %u.\n",
map_name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
} else if (strcmp(name, "value") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': value type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %lld.\n",
map_name, t->type, sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %lld.\n",
map_name, t->type, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %lld.\n",
map_name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (!get_map_field_int(map_name, obj->btf, def, m,
&val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map_name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map_name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map_name);
return err;
}
}
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n",
map_name, name);
return -ENOTSUP;
}
pr_debug("map '%s': ignoring unknown field '%s'.\n",
map_name, name);
}
}
if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
pr_warn("map '%s': map type isn't specified.\n", map_name);
return -EINVAL;
}
return 0;
}
static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
const char *pin_root_path)
{
const struct btf_type *sec = NULL;
int nr_types, i, vlen, err;
const struct btf_type *t;
const char *name;
Elf_Data *data;
Elf_Scn *scn;
if (obj->efile.btf_maps_shndx < 0)
return 0;
scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
if (scn)
data = elf_getdata(scn, NULL);
if (!scn || !data) {
pr_warn("failed to get Elf_Data from map section %d (%s)\n",
obj->efile.maps_shndx, MAPS_ELF_SEC);
return -EINVAL;
}
nr_types = btf__get_nr_types(obj->btf);
for (i = 1; i <= nr_types; i++) {
t = btf__type_by_id(obj->btf, i);
if (!btf_is_datasec(t))
continue;
name = btf__name_by_offset(obj->btf, t->name_off);
if (strcmp(name, MAPS_ELF_SEC) == 0) {
sec = t;
break;
}
}
if (!sec) {
pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
return -ENOENT;
}
vlen = btf_vlen(sec);
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
data, strict, pin_root_path);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps,
const char *pin_root_path)
{
bool strict = !relaxed_maps;
int err;
err = bpf_object__init_user_maps(obj, strict);
if (err)
return err;
err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
if (err)
return err;
err = bpf_object__init_global_data_maps(obj);
if (err)
return err;
if (obj->nr_maps) {
qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
compare_bpf_map);
}
return 0;
}
static bool section_have_execinstr(struct bpf_object *obj, int idx)
{
Elf_Scn *scn;
GElf_Shdr sh;
scn = elf_getscn(obj->efile.elf, idx);
if (!scn)
return false;
if (gelf_getshdr(scn, &sh) != &sh)
return false;
if (sh.sh_flags & SHF_EXECINSTR)
return true;
return false;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj)
{
bool has_datasec = obj->caps.btf_datasec;
bool has_func = obj->caps.btf_func;
struct btf *btf = obj->btf;
struct btf_type *t;
int i, j, vlen;
if (!obj->btf || (has_func && has_datasec))
return;
for (i = 1; i <= btf__get_nr_types(btf); i++) {
t = (struct btf_type *)btf__type_by_id(btf, i);
if (!has_datasec && btf_is_var(t)) {
/* replace VAR with INT */
t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
/*
* using size = 1 is the safest choice, 4 will be too
* big and cause kernel BTF validation failure if
* original variable took less than 4 bytes
*/
t->size = 1;
*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
} else if (!has_datasec && btf_is_datasec(t)) {
/* replace DATASEC with STRUCT */
const struct btf_var_secinfo *v = btf_var_secinfos(t);
struct btf_member *m = btf_members(t);
struct btf_type *vt;
char *name;
name = (char *)btf__name_by_offset(btf, t->name_off);
while (*name) {
if (*name == '.')
*name = '_';
name++;
}
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
for (j = 0; j < vlen; j++, v++, m++) {
/* order of field assignments is important */
m->offset = v->offset * 8;
m->type = v->type;
/* preserve variable name as member name */
vt = (void *)btf__type_by_id(btf, v->type);
m->name_off = vt->name_off;
}
} else if (!has_func && btf_is_func_proto(t)) {
/* replace FUNC_PROTO with ENUM */
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
t->size = sizeof(__u32); /* kernel enforced */
} else if (!has_func && btf_is_func(t)) {
/* replace FUNC with TYPEDEF */
t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
}
}
}
static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
{
if (!obj->btf_ext)
return;
if (!obj->caps.btf_func) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
}
static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
{
return obj->efile.btf_maps_shndx >= 0;
}
static int bpf_object__init_btf(struct bpf_object *obj,
Elf_Data *btf_data,
Elf_Data *btf_ext_data)
{
bool btf_required = bpf_object__is_btf_mandatory(obj);
int err = 0;
if (btf_data) {
obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
if (IS_ERR(obj->btf)) {
pr_warn("Error loading ELF section %s: %d.\n",
BTF_ELF_SEC, err);
goto out;
}
err = btf__finalize_data(obj, obj->btf);
if (err) {
pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
goto out;
}
}
if (btf_ext_data) {
if (!obj->btf) {
pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
BTF_EXT_ELF_SEC, BTF_ELF_SEC);
goto out;
}
obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
btf_ext_data->d_size);
if (IS_ERR(obj->btf_ext)) {
pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n",
BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
obj->btf_ext = NULL;
goto out;
}
}
out:
if (err || IS_ERR(obj->btf)) {
if (btf_required)
err = err ? : PTR_ERR(obj->btf);
else
err = 0;
if (!IS_ERR_OR_NULL(obj->btf))
btf__free(obj->btf);
obj->btf = NULL;
}
if (btf_required && !obj->btf) {
pr_warn("BTF is required, but is missing or corrupted.\n");
return err == 0 ? -ENOENT : err;
}
return 0;
}
static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
{
int err = 0;
if (!obj->btf)
return 0;
bpf_object__sanitize_btf(obj);
bpf_object__sanitize_btf_ext(obj);
err = btf__load(obj->btf);
if (err) {
pr_warn("Error loading %s into kernel: %d.\n",
BTF_ELF_SEC, err);
btf__free(obj->btf);
obj->btf = NULL;
/* btf_ext can't exist without btf, so free it as well */
if (obj->btf_ext) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
if (bpf_object__is_btf_mandatory(obj))
return err;
}
return 0;
}
static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
const char *pin_root_path)
{
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
Elf_Data *btf_ext_data = NULL;
Elf_Data *btf_data = NULL;
Elf_Scn *scn = NULL;
int idx = 0, err = 0;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
while ((scn = elf_nextscn(elf, scn)) != NULL) {
char *name;
GElf_Shdr sh;
Elf_Data *data;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
idx, name, (unsigned long)data->d_size,
(int)sh.sh_link, (unsigned long)sh.sh_flags,
(int)sh.sh_type);
if (strcmp(name, "license") == 0) {
err = bpf_object__init_license(obj,
data->d_buf,
data->d_size);
if (err)
return err;
} else if (strcmp(name, "version") == 0) {
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
if (err)
return err;
} else if (strcmp(name, "maps") == 0) {
obj->efile.maps_shndx = idx;
} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
obj->efile.btf_maps_shndx = idx;
} else if (strcmp(name, BTF_ELF_SEC) == 0) {
btf_data = data;
} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
btf_ext_data = data;
} else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warn("bpf: multiple SYMTAB in %s\n",
obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
obj->efile.symbols = data;
obj->efile.strtabidx = sh.sh_link;
} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
if (sh.sh_flags & SHF_EXECINSTR) {
if (strcmp(name, ".text") == 0)
obj->efile.text_shndx = idx;
err = bpf_object__add_program(obj, data->d_buf,
data->d_size, name, idx);
if (err) {
char errmsg[STRERR_BUFSIZE];
char *cp = libbpf_strerror_r(-err, errmsg,
sizeof(errmsg));
pr_warn("failed to alloc program %s (%s): %s",
name, obj->path, cp);
return err;
}
} else if (strcmp(name, ".data") == 0) {
obj->efile.data = data;
obj->efile.data_shndx = idx;
} else if (strcmp(name, ".rodata") == 0) {
obj->efile.rodata = data;
obj->efile.rodata_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
} else if (sh.sh_type == SHT_REL) {
int nr_reloc = obj->efile.nr_reloc;
void *reloc = obj->efile.reloc;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
if (!section_have_execinstr(obj, sec)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
}
reloc = reallocarray(reloc, nr_reloc + 1,
sizeof(*obj->efile.reloc));
if (!reloc) {
pr_warn("realloc failed\n");
return -ENOMEM;
}
obj->efile.reloc = reloc;
obj->efile.nr_reloc++;
obj->efile.reloc[nr_reloc].shdr = sh;
obj->efile.reloc[nr_reloc].data = data;
} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
}
if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
pr_warn("Corrupted ELF file: index of strtab invalid\n");
return -LIBBPF_ERRNO__FORMAT;
}
err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
if (!err)
err = bpf_object__init_maps(obj, relaxed_maps, pin_root_path);
if (!err)
err = bpf_object__sanitize_and_load_btf(obj);
if (!err)
err = bpf_object__init_prog_names(obj);
return err;
}
static struct bpf_program *
bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
{
struct bpf_program *prog;
size_t i;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (prog->idx == idx)
return prog;
}
return NULL;
}
struct bpf_program *
bpf_object__find_program_by_title(const struct bpf_object *obj,
const char *title)
{
struct bpf_program *pos;
bpf_object__for_each_program(pos, obj) {
if (pos->section_name && !strcmp(pos->section_name, title))
return pos;
}
return NULL;
}
static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.data_shndx ||
shndx == obj->efile.bss_shndx ||
shndx == obj->efile.rodata_shndx;
}
static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.maps_shndx ||
shndx == obj->efile.btf_maps_shndx;
}
static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.text_shndx ||
bpf_object__shndx_is_maps(obj, shndx) ||
bpf_object__shndx_is_data(obj, shndx);
}
static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
{
if (shndx == obj->efile.data_shndx)
return LIBBPF_MAP_DATA;
else if (shndx == obj->efile.bss_shndx)
return LIBBPF_MAP_BSS;
else if (shndx == obj->efile.rodata_shndx)
return LIBBPF_MAP_RODATA;
else
return LIBBPF_MAP_UNSPEC;
}
static int
bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
Elf_Data *data, struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
struct bpf_map *maps = obj->maps;
size_t nr_maps = obj->nr_maps;
int i, nrels;
pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
nrels = shdr->sh_size / shdr->sh_entsize;
prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
if (!prog->reloc_desc) {
pr_warn("failed to alloc memory in relocation\n");
return -ENOMEM;
}
prog->nr_reloc = nrels;
for (i = 0; i < nrels; i++) {
struct bpf_insn *insns = prog->insns;
enum libbpf_map_type type;
unsigned int insn_idx;
unsigned int shdr_idx;
const char *name;
size_t map_idx;
GElf_Sym sym;
GElf_Rel rel;
if (!gelf_getrel(data, i, &rel)) {
pr_warn("relocation: failed to get %d reloc\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn("relocation: symbol %"PRIx64" not found\n",
GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name) ? : "<?>";
pr_debug("relo for %lld value %lld name %d (\'%s\')\n",
(long long) (rel.r_info >> 32),
(long long) sym.st_value, sym.st_name, name);
shdr_idx = sym.st_shndx;
insn_idx = rel.r_offset / sizeof(struct bpf_insn);
pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n",
insn_idx, shdr_idx);
if (shdr_idx >= SHN_LORESERVE) {
pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
name, shdr_idx, insn_idx,
insns[insn_idx].code);
return -LIBBPF_ERRNO__RELOC;
}
if (!bpf_object__relo_in_known_section(obj, shdr_idx)) {
pr_warn("Program '%s' contains unrecognized relo data pointing to section %u\n",
prog->section_name, shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
pr_warn("incorrect bpf_call opcode\n");
return -LIBBPF_ERRNO__RELOC;
}
prog->reloc_desc[i].type = RELO_CALL;
prog->reloc_desc[i].insn_idx = insn_idx;
prog->reloc_desc[i].text_off = sym.st_value;
obj->has_pseudo_calls = true;
continue;
}
if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
insn_idx, insns[insn_idx].code);
return -LIBBPF_ERRNO__RELOC;
}
if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
bpf_object__shndx_is_data(obj, shdr_idx)) {
type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
if (type != LIBBPF_MAP_UNSPEC) {
if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
pr_warn("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
name, insn_idx, insns[insn_idx].code);
return -LIBBPF_ERRNO__RELOC;
}
if (!obj->caps.global_data) {
pr_warn("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
name, insn_idx);
return -LIBBPF_ERRNO__RELOC;
}
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
if (maps[map_idx].libbpf_type != type)
continue;
if (type != LIBBPF_MAP_UNSPEC ||
(maps[map_idx].sec_idx == sym.st_shndx &&
maps[map_idx].sec_offset == sym.st_value)) {
pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
map_idx, maps[map_idx].name,
maps[map_idx].sec_idx,
maps[map_idx].sec_offset,
insn_idx);
break;
}
}
if (map_idx >= nr_maps) {
pr_warn("bpf relocation: map_idx %d larger than %d\n",
(int)map_idx, (int)nr_maps - 1);
return -LIBBPF_ERRNO__RELOC;
}
prog->reloc_desc[i].type = type != LIBBPF_MAP_UNSPEC ?
RELO_DATA : RELO_LD64;
prog->reloc_desc[i].insn_idx = insn_idx;
prog->reloc_desc[i].map_idx = map_idx;
}
}
return 0;
}
static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
{
struct bpf_map_def *def = &map->def;
__u32 key_type_id = 0, value_type_id = 0;
int ret;
/* if it's BTF-defined map, we don't need to search for type IDs */
if (map->sec_idx == obj->efile.btf_maps_shndx)
return 0;
if (!bpf_map__is_internal(map)) {
ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
def->value_size, &key_type_id,
&value_type_id);
} else {
/*
* LLVM annotates global data differently in BTF, that is,
* only as '.data', '.bss' or '.rodata'.
*/
ret = btf__find_by_name(obj->btf,
libbpf_type_to_btf_name[map->libbpf_type]);
}
if (ret < 0)
return ret;
map->btf_key_type_id = key_type_id;
map->btf_value_type_id = bpf_map__is_internal(map) ?
ret : value_type_id;
return 0;
}
int bpf_map__reuse_fd(struct bpf_map *map, int fd)
{
struct bpf_map_info info = {};
__u32 len = sizeof(info);
int new_fd, err;
char *new_name;
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err)
return err;
new_name = strdup(info.name);
if (!new_name)
return -errno;
new_fd = open("/", O_RDONLY | O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_free_new_name;
}
new_fd = dup3(fd, new_fd, O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_close_new_fd;
}
err = zclose(map->fd);
if (err) {
err = -errno;
goto err_close_new_fd;
}
free(map->name);
map->fd = new_fd;
map->name = new_name;
map->def.type = info.type;
map->def.key_size = info.key_size;
map->def.value_size = info.value_size;
map->def.max_entries = info.max_entries;
map->def.map_flags = info.map_flags;
map->btf_key_type_id = info.btf_key_type_id;
map->btf_value_type_id = info.btf_value_type_id;
map->reused = true;
return 0;
err_close_new_fd:
close(new_fd);
err_free_new_name:
free(new_name);
return err;
}
int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
{
if (!map || !max_entries)
return -EINVAL;
/* If map already created, its attributes can't be changed. */
if (map->fd >= 0)
return -EBUSY;
map->def.max_entries = max_entries;
return 0;
}
static int
bpf_object__probe_name(struct bpf_object *obj)
{
struct bpf_load_program_attr attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret;
/* make sure basic loading works */
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
ret = bpf_load_program_xattr(&attr, NULL, 0);
if (ret < 0) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't load basic 'r0 = 0' BPF program.\n",
__func__, cp, errno);
return -errno;
}
close(ret);
/* now try the same program, but with the name */
attr.name = "test";
ret = bpf_load_program_xattr(&attr, NULL, 0);
if (ret >= 0) {
obj->caps.name = 1;
close(ret);
}
return 0;
}
static int
bpf_object__probe_global_data(struct bpf_object *obj)
{
struct bpf_load_program_attr prg_attr;
struct bpf_create_map_attr map_attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret, map;
memset(&map_attr, 0, sizeof(map_attr));
map_attr.map_type = BPF_MAP_TYPE_ARRAY;
map_attr.key_size = sizeof(int);
map_attr.value_size = 32;
map_attr.max_entries = 1;
map = bpf_create_map_xattr(&map_attr);
if (map < 0) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
__func__, cp, errno);
return -errno;
}
insns[0].imm = map;
memset(&prg_attr, 0, sizeof(prg_attr));
prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
prg_attr.insns = insns;
prg_attr.insns_cnt = ARRAY_SIZE(insns);
prg_attr.license = "GPL";
ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
if (ret >= 0) {
obj->caps.global_data = 1;
close(ret);
}
close(map);
return 0;
}
static int bpf_object__probe_btf_func(struct bpf_object *obj)
{
const char strs[] = "\0int\0x\0a";
/* void x(int a) {} */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* FUNC_PROTO */ /* [2] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
BTF_PARAM_ENC(7, 1),
/* FUNC x */ /* [3] */
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
};
int btf_fd;
btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs));
if (btf_fd >= 0) {
obj->caps.btf_func = 1;
close(btf_fd);
return 1;
}
return 0;
}
static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
{
const char strs[] = "\0x\0.data";
/* static int a; */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* VAR x */ /* [2] */
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
BTF_VAR_STATIC,
/* DATASEC val */ /* [3] */
BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
BTF_VAR_SECINFO_ENC(2, 0, 4),
};
int btf_fd;
btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs));
if (btf_fd >= 0) {
obj->caps.btf_datasec = 1;
close(btf_fd);
return 1;
}
return 0;
}
static int
bpf_object__probe_caps(struct bpf_object *obj)
{
int (*probe_fn[])(struct bpf_object *obj) = {
bpf_object__probe_name,
bpf_object__probe_global_data,
bpf_object__probe_btf_func,
bpf_object__probe_btf_datasec,
};
int i, ret;
for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
ret = probe_fn[i](obj);
if (ret < 0)
pr_debug("Probe #%d failed with %d.\n", i, ret);
}
return 0;
}
static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
{
struct bpf_map_info map_info = {};
char msg[STRERR_BUFSIZE];
__u32 map_info_len;
map_info_len = sizeof(map_info);
if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) {
pr_warn("failed to get map info for map FD %d: %s\n",
map_fd, libbpf_strerror_r(errno, msg, sizeof(msg)));
return false;
}
return (map_info.type == map->def.type &&
map_info.key_size == map->def.key_size &&
map_info.value_size == map->def.value_size &&
map_info.max_entries == map->def.max_entries &&
map_info.map_flags == map->def.map_flags);
}
static int
bpf_object__reuse_map(struct bpf_map *map)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err, pin_fd;
pin_fd = bpf_obj_get(map->pin_path);
if (pin_fd < 0) {
err = -errno;
if (err == -ENOENT) {
pr_debug("found no pinned map to reuse at '%s'\n",
map->pin_path);
return 0;
}
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("couldn't retrieve pinned map '%s': %s\n",
map->pin_path, cp);
return err;
}
if (!map_is_reuse_compat(map, pin_fd)) {
pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
map->pin_path);
close(pin_fd);
return -EINVAL;
}
err = bpf_map__reuse_fd(map, pin_fd);
if (err) {
close(pin_fd);
return err;
}
map->pinned = true;
pr_debug("reused pinned map at '%s'\n", map->pin_path);
return 0;
}
static int
bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err, zero = 0;
__u8 *data;
/* Nothing to do here since kernel already zero-initializes .bss map. */
if (map->libbpf_type == LIBBPF_MAP_BSS)
return 0;
data = map->libbpf_type == LIBBPF_MAP_DATA ?
obj->sections.data : obj->sections.rodata;
err = bpf_map_update_elem(map->fd, &zero, data, 0);
/* Freeze .rodata map as read-only from syscall side. */
if (!err && map->libbpf_type == LIBBPF_MAP_RODATA) {
err = bpf_map_freeze(map->fd);
if (err) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error freezing map(%s) as read-only: %s\n",
map->name, cp);
err = 0;
}
}
return err;
}
static int
bpf_object__create_maps(struct bpf_object *obj)
{
struct bpf_create_map_attr create_attr = {};
int nr_cpus = 0;
unsigned int i;
int err;
for (i = 0; i < obj->nr_maps; i++) {
struct bpf_map *map = &obj->maps[i];
struct bpf_map_def *def = &map->def;
char *cp, errmsg[STRERR_BUFSIZE];
int *pfd = &map->fd;
if (map->pin_path) {
err = bpf_object__reuse_map(map);
if (err) {
pr_warn("error reusing pinned map %s\n",
map->name);
return err;
}
}
if (map->fd >= 0) {
pr_debug("skip map create (preset) %s: fd=%d\n",
map->name, map->fd);
continue;
}
if (obj->caps.name)
create_attr.name = map->name;
create_attr.map_ifindex = map->map_ifindex;
create_attr.map_type = def->type;
create_attr.map_flags = def->map_flags;
create_attr.key_size = def->key_size;
create_attr.value_size = def->value_size;
if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
!def->max_entries) {
if (!nr_cpus)
nr_cpus = libbpf_num_possible_cpus();
if (nr_cpus < 0) {
pr_warn("failed to determine number of system CPUs: %d\n",
nr_cpus);
err = nr_cpus;
goto err_out;
}
pr_debug("map '%s': setting size to %d\n",
map->name, nr_cpus);
create_attr.max_entries = nr_cpus;
} else {
create_attr.max_entries = def->max_entries;
}
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
if (bpf_map_type__is_map_in_map(def->type) &&
map->inner_map_fd >= 0)
create_attr.inner_map_fd = map->inner_map_fd;
if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
create_attr.btf_fd = btf__fd(obj->btf);
create_attr.btf_key_type_id = map->btf_key_type_id;
create_attr.btf_value_type_id = map->btf_value_type_id;
}
*pfd = bpf_create_map_xattr(&create_attr);
if (*pfd < 0 && (create_attr.btf_key_type_id ||
create_attr.btf_value_type_id)) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
map->name, cp, err);
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
*pfd = bpf_create_map_xattr(&create_attr);
}
if (*pfd < 0) {
size_t j;
err = -errno;
err_out:
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to create map (name: '%s'): %s(%d)\n",
map->name, cp, err);
for (j = 0; j < i; j++)
zclose(obj->maps[j].fd);
return err;
}
if (bpf_map__is_internal(map)) {
err = bpf_object__populate_internal_map(obj, map);
if (err < 0) {
zclose(*pfd);
goto err_out;
}
}
if (map->pin_path && !map->pinned) {
err = bpf_map__pin(map, NULL);
if (err) {
pr_warn("failed to auto-pin map name '%s' at '%s'\n",
map->name, map->pin_path);
return err;
}
}
pr_debug("created map %s: fd=%d\n", map->name, *pfd);
}
return 0;
}
static int
check_btf_ext_reloc_err(struct bpf_program *prog, int err,
void *btf_prog_info, const char *info_name)
{
if (err != -ENOENT) {
pr_warn("Error in loading %s for sec %s.\n",
info_name, prog->section_name);
return err;
}
/* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
if (btf_prog_info) {
/*
* Some info has already been found but has problem
* in the last btf_ext reloc. Must have to error out.
*/
pr_warn("Error in relocating %s for sec %s.\n",
info_name, prog->section_name);
return err;
}
/* Have problem loading the very first info. Ignore the rest. */
pr_warn("Cannot find %s for main program sec %s. Ignore all %s.\n",
info_name, prog->section_name, info_name);
return 0;
}
static int
bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
const char *section_name, __u32 insn_offset)
{
int err;
if (!insn_offset || prog->func_info) {
/*
* !insn_offset => main program
*
* For sub prog, the main program's func_info has to
* be loaded first (i.e. prog->func_info != NULL)
*/
err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
section_name, insn_offset,
&prog->func_info,
&prog->func_info_cnt);
if (err)
return check_btf_ext_reloc_err(prog, err,
prog->func_info,
"bpf_func_info");
prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
}
if (!insn_offset || prog->line_info) {
err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
section_name, insn_offset,
&prog->line_info,
&prog->line_info_cnt);
if (err)
return check_btf_ext_reloc_err(prog, err,
prog->line_info,
"bpf_line_info");
prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
}
return 0;
}
#define BPF_CORE_SPEC_MAX_LEN 64
/* represents BPF CO-RE field or array element accessor */
struct bpf_core_accessor {
__u32 type_id; /* struct/union type or array element type */
__u32 idx; /* field index or array index */
const char *name; /* field name or NULL for array accessor */
};
struct bpf_core_spec {
const struct btf *btf;
/* high-level spec: named fields and array indices only */
struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
/* high-level spec length */
int len;
/* raw, low-level spec: 1-to-1 with accessor spec string */
int raw_spec[BPF_CORE_SPEC_MAX_LEN];
/* raw spec length */
int raw_len;
/* field bit offset represented by spec */
__u32 bit_offset;
};
static bool str_is_empty(const char *s)
{
return !s || !s[0];
}
/*
* Turn bpf_field_reloc into a low- and high-level spec representation,
* validating correctness along the way, as well as calculating resulting
* field bit offset, specified by accessor string. Low-level spec captures
* every single level of nestedness, including traversing anonymous
* struct/union members. High-level one only captures semantically meaningful
* "turning points": named fields and array indicies.
* E.g., for this case:
*
* struct sample {
* int __unimportant;
* struct {
* int __1;
* int __2;
* int a[7];
* };
* };
*
* struct sample *s = ...;
*
* int x = &s->a[3]; // access string = '0:1:2:3'
*
* Low-level spec has 1:1 mapping with each element of access string (it's
* just a parsed access string representation): [0, 1, 2, 3].
*
* High-level spec will capture only 3 points:
* - intial zero-index access by pointer (&s->... is the same as &s[0]...);
* - field 'a' access (corresponds to '2' in low-level spec);
* - array element #3 access (corresponds to '3' in low-level spec).
*
*/
static int bpf_core_spec_parse(const struct btf *btf,
__u32 type_id,
const char *spec_str,
struct bpf_core_spec *spec)
{
int access_idx, parsed_len, i;
const struct btf_type *t;
const char *name;
__u32 id;
__s64 sz;
if (str_is_empty(spec_str) || *spec_str == ':')
return -EINVAL;
memset(spec, 0, sizeof(*spec));
spec->btf = btf;
/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
while (*spec_str) {
if (*spec_str == ':')
++spec_str;
if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
return -EINVAL;
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
spec_str += parsed_len;
spec->raw_spec[spec->raw_len++] = access_idx;
}
if (spec->raw_len == 0)
return -EINVAL;
/* first spec value is always reloc type array index */
t = skip_mods_and_typedefs(btf, type_id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[0];
spec->spec[0].type_id = id;
spec->spec[0].idx = access_idx;
spec->len++;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset = access_idx * sz * 8;
for (i = 1; i < spec->raw_len; i++) {
t = skip_mods_and_typedefs(btf, id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[i];
if (btf_is_composite(t)) {
const struct btf_member *m;
__u32 bit_offset;
if (access_idx >= btf_vlen(t))
return -EINVAL;
bit_offset = btf_member_bit_offset(t, access_idx);
spec->bit_offset += bit_offset;
m = btf_members(t) + access_idx;
if (m->name_off) {
name = btf__name_by_offset(btf, m->name_off);
if (str_is_empty(name))
return -EINVAL;
spec->spec[spec->len].type_id = id;
spec->spec[spec->len].idx = access_idx;
spec->spec[spec->len].name = name;
spec->len++;
}
id = m->type;
} else if (btf_is_array(t)) {
const struct btf_array *a = btf_array(t);
t = skip_mods_and_typedefs(btf, a->type, &id);
if (!t || access_idx >= a->nelems)
return -EINVAL;
spec->spec[spec->len].type_id = id;
spec->spec[spec->len].idx = access_idx;
spec->len++;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset += access_idx * sz * 8;
} else {
pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
type_id, spec_str, i, id, btf_kind(t));
return -EINVAL;
}
}
return 0;
}
static bool bpf_core_is_flavor_sep(const char *s)
{
/* check X___Y name pattern, where X and Y are not underscores */
return s[0] != '_' && /* X */
s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
s[4] != '_'; /* Y */
}
/* Given 'some_struct_name___with_flavor' return the length of a name prefix
* before last triple underscore. Struct name part after last triple
* underscore is ignored by BPF CO-RE relocation during relocation matching.
*/
static size_t bpf_core_essential_name_len(const char *name)
{
size_t n = strlen(name);
int i;
for (i = n - 5; i >= 0; i--) {
if (bpf_core_is_flavor_sep(name + i))
return i + 1;
}
return n;
}
/* dynamically sized list of type IDs */
struct ids_vec {
__u32 *data;
int len;
};
static void bpf_core_free_cands(struct ids_vec *cand_ids)
{
free(cand_ids->data);
free(cand_ids);
}
static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
__u32 local_type_id,
const struct btf *targ_btf)
{
size_t local_essent_len, targ_essent_len;
const char *local_name, *targ_name;
const struct btf_type *t;
struct ids_vec *cand_ids;
__u32 *new_ids;
int i, err, n;
t = btf__type_by_id(local_btf, local_type_id);
if (!t)
return ERR_PTR(-EINVAL);
local_name = btf__name_by_offset(local_btf, t->name_off);
if (str_is_empty(local_name))
return ERR_PTR(-EINVAL);
local_essent_len = bpf_core_essential_name_len(local_name);
cand_ids = calloc(1, sizeof(*cand_ids));
if (!cand_ids)
return ERR_PTR(-ENOMEM);
n = btf__get_nr_types(targ_btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(targ_btf, i);
targ_name = btf__name_by_offset(targ_btf, t->name_off);
if (str_is_empty(targ_name))
continue;
targ_essent_len = bpf_core_essential_name_len(targ_name);
if (targ_essent_len != local_essent_len)
continue;
if (strncmp(local_name, targ_name, local_essent_len) == 0) {
pr_debug("[%d] %s: found candidate [%d] %s\n",
local_type_id, local_name, i, targ_name);
new_ids = realloc(cand_ids->data, cand_ids->len + 1);
if (!new_ids) {
err = -ENOMEM;
goto err_out;
}
cand_ids->data = new_ids;
cand_ids->data[cand_ids->len++] = i;
}
}
return cand_ids;
err_out:
bpf_core_free_cands(cand_ids);
return ERR_PTR(err);
}
/* Check two types for compatibility, skipping const/volatile/restrict and
* typedefs, to ensure we are relocating compatible entities:
* - any two STRUCTs/UNIONs are compatible and can be mixed;
* - any two FWDs are compatible, if their names match (modulo flavor suffix);
* - any two PTRs are always compatible;
* - for ENUMs, names should be the same (ignoring flavor suffix) or at
* least one of enums should be anonymous;
* - for ENUMs, check sizes, names are ignored;
* - for INT, size and signedness are ignored;
* - for ARRAY, dimensionality is ignored, element types are checked for
* compatibility recursively;
* - everything else shouldn't be ever a target of relocation.
* These rules are not set in stone and probably will be adjusted as we get
* more experience with using BPF CO-RE relocations.
*/
static int bpf_core_fields_are_compat(const struct btf *local_btf,
__u32 local_id,
const struct btf *targ_btf,
__u32 targ_id)
{
const struct btf_type *local_type, *targ_type;
recur:
local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!local_type || !targ_type)
return -EINVAL;
if (btf_is_composite(local_type) && btf_is_composite(targ_type))
return 1;
if (btf_kind(local_type) != btf_kind(targ_type))
return 0;
switch (btf_kind(local_type)) {
case BTF_KIND_PTR:
return 1;
case BTF_KIND_FWD:
case BTF_KIND_ENUM: {
const char *local_name, *targ_name;
size_t local_len, targ_len;
local_name = btf__name_by_offset(local_btf,
local_type->name_off);
targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
local_len = bpf_core_essential_name_len(local_name);
targ_len = bpf_core_essential_name_len(targ_name);
/* one of them is anonymous or both w/ same flavor-less names */
return local_len == 0 || targ_len == 0 ||
(local_len == targ_len &&
strncmp(local_name, targ_name, local_len) == 0);
}
case BTF_KIND_INT:
/* just reject deprecated bitfield-like integers; all other
* integers are by default compatible between each other
*/
return btf_int_offset(local_type) == 0 &&
btf_int_offset(targ_type) == 0;
case BTF_KIND_ARRAY:
local_id = btf_array(local_type)->type;
targ_id = btf_array(targ_type)->type;
goto recur;
default:
pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
btf_kind(local_type), local_id, targ_id);
return 0;
}
}
/*
* Given single high-level named field accessor in local type, find
* corresponding high-level accessor for a target type. Along the way,
* maintain low-level spec for target as well. Also keep updating target
* bit offset.
*
* Searching is performed through recursive exhaustive enumeration of all
* fields of a struct/union. If there are any anonymous (embedded)
* structs/unions, they are recursively searched as well. If field with
* desired name is found, check compatibility between local and target types,
* before returning result.
*
* 1 is returned, if field is found.
* 0 is returned if no compatible field is found.
* <0 is returned on error.
*/
static int bpf_core_match_member(const struct btf *local_btf,
const struct bpf_core_accessor *local_acc,
const struct btf *targ_btf,
__u32 targ_id,
struct bpf_core_spec *spec,
__u32 *next_targ_id)
{
const struct btf_type *local_type, *targ_type;
const struct btf_member *local_member, *m;
const char *local_name, *targ_name;
__u32 local_id;
int i, n, found;
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!targ_type)
return -EINVAL;
if (!btf_is_composite(targ_type))
return 0;
local_id = local_acc->type_id;
local_type = btf__type_by_id(local_btf, local_id);
local_member = btf_members(local_type) + local_acc->idx;
local_name = btf__name_by_offset(local_btf, local_member->name_off);
n = btf_vlen(targ_type);
m = btf_members(targ_type);
for (i = 0; i < n; i++, m++) {
__u32 bit_offset;
bit_offset = btf_member_bit_offset(targ_type, i);
/* too deep struct/union/array nesting */
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
/* speculate this member will be the good one */
spec->bit_offset += bit_offset;
spec->raw_spec[spec->raw_len++] = i;
targ_name = btf__name_by_offset(targ_btf, m->name_off);
if (str_is_empty(targ_name)) {
/* embedded struct/union, we need to go deeper */
found = bpf_core_match_member(local_btf, local_acc,
targ_btf, m->type,
spec, next_targ_id);
if (found) /* either found or error */
return found;
} else if (strcmp(local_name, targ_name) == 0) {
/* matching named field */
struct bpf_core_accessor *targ_acc;
targ_acc = &spec->spec[spec->len++];
targ_acc->type_id = targ_id;
targ_acc->idx = i;
targ_acc->name = targ_name;
*next_targ_id = m->type;
found = bpf_core_fields_are_compat(local_btf,
local_member->type,
targ_btf, m->type);
if (!found)
spec->len--; /* pop accessor */
return found;
}
/* member turned out not to be what we looked for */
spec->bit_offset -= bit_offset;
spec->raw_len--;
}
return 0;
}
/*
* Try to match local spec to a target type and, if successful, produce full
* target spec (high-level, low-level + bit offset).
*/
static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
const struct btf *targ_btf, __u32 targ_id,
struct bpf_core_spec *targ_spec)
{
const struct btf_type *targ_type;
const struct bpf_core_accessor *local_acc;
struct bpf_core_accessor *targ_acc;
int i, sz, matched;
memset(targ_spec, 0, sizeof(*targ_spec));
targ_spec->btf = targ_btf;
local_acc = &local_spec->spec[0];
targ_acc = &targ_spec->spec[0];
for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
&targ_id);
if (!targ_type)
return -EINVAL;
if (local_acc->name) {
matched = bpf_core_match_member(local_spec->btf,
local_acc,
targ_btf, targ_id,
targ_spec, &targ_id);
if (matched <= 0)
return matched;
} else {
/* for i=0, targ_id is already treated as array element
* type (because it's the original struct), for others
* we should find array element type first
*/
if (i > 0) {
const struct btf_array *a;
if (!btf_is_array(targ_type))
return 0;
a = btf_array(targ_type);
if (local_acc->idx >= a->nelems)
return 0;
if (!skip_mods_and_typedefs(targ_btf, a->type,
&targ_id))
return -EINVAL;
}
/* too deep struct/union/array nesting */
if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
targ_acc->type_id = targ_id;
targ_acc->idx = local_acc->idx;
targ_acc->name = NULL;
targ_spec->len++;
targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
targ_spec->raw_len++;
sz = btf__resolve_size(targ_btf, targ_id);
if (sz < 0)
return sz;
targ_spec->bit_offset += local_acc->idx * sz * 8;
}
}
return 1;
}
static int bpf_core_calc_field_relo(const struct bpf_program *prog,
const struct bpf_field_reloc *relo,
const struct bpf_core_spec *spec,
__u32 *val, bool *validate)
{
const struct bpf_core_accessor *acc = &spec->spec[spec->len - 1];
const struct btf_type *t = btf__type_by_id(spec->btf, acc->type_id);
__u32 byte_off, byte_sz, bit_off, bit_sz;
const struct btf_member *m;
const struct btf_type *mt;
bool bitfield;
__s64 sz;
/* a[n] accessor needs special handling */
if (!acc->name) {
if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
*val = spec->bit_offset / 8;
} else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
sz = btf__resolve_size(spec->btf, acc->type_id);
if (sz < 0)
return -EINVAL;
*val = sz;
} else {
pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -EINVAL;
}
if (validate)
*validate = true;
return 0;
}
m = btf_members(t) + acc->idx;
mt = skip_mods_and_typedefs(spec->btf, m->type, NULL);
bit_off = spec->bit_offset;
bit_sz = btf_member_bitfield_size(t, acc->idx);
bitfield = bit_sz > 0;
if (bitfield) {
byte_sz = mt->size;
byte_off = bit_off / 8 / byte_sz * byte_sz;
/* figure out smallest int size necessary for bitfield load */
while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
if (byte_sz >= 8) {
/* bitfield can't be read with 64-bit read */
pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -E2BIG;
}
byte_sz *= 2;
byte_off = bit_off / 8 / byte_sz * byte_sz;
}
} else {
sz = btf__resolve_size(spec->btf, m->type);
if (sz < 0)
return -EINVAL;
byte_sz = sz;
byte_off = spec->bit_offset / 8;
bit_sz = byte_sz * 8;
}
/* for bitfields, all the relocatable aspects are ambiguous and we
* might disagree with compiler, so turn off validation of expected
* value, except for signedness
*/
if (validate)
*validate = !bitfield;
switch (relo->kind) {
case BPF_FIELD_BYTE_OFFSET:
*val = byte_off;
break;
case BPF_FIELD_BYTE_SIZE:
*val = byte_sz;
break;
case BPF_FIELD_SIGNED:
/* enums will be assumed unsigned */
*val = btf_is_enum(mt) ||
(btf_int_encoding(mt) & BTF_INT_SIGNED);
if (validate)
*validate = true; /* signedness is never ambiguous */
break;
case BPF_FIELD_LSHIFT_U64:
#if __BYTE_ORDER == __LITTLE_ENDIAN
*val = 64 - (bit_off + bit_sz - byte_off * 8);
#else
*val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
#endif
break;
case BPF_FIELD_RSHIFT_U64:
*val = 64 - bit_sz;
if (validate)
*validate = true; /* right shift is never ambiguous */
break;
case BPF_FIELD_EXISTS:
default:
pr_warn("prog '%s': unknown relo %d at insn #%d\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -EINVAL;
}
return 0;
}
/*
* Patch relocatable BPF instruction.
*
* Patched value is determined by relocation kind and target specification.
* For field existence relocation target spec will be NULL if field is not
* found.
* Expected insn->imm value is determined using relocation kind and local
* spec, and is checked before patching instruction. If actual insn->imm value
* is wrong, bail out with error.
*
* Currently three kinds of BPF instructions are supported:
* 1. rX = <imm> (assignment with immediate operand);
* 2. rX += <imm> (arithmetic operations with immediate operand);
*/
static int bpf_core_reloc_insn(struct bpf_program *prog,
const struct bpf_field_reloc *relo,
const struct bpf_core_spec *local_spec,
const struct bpf_core_spec *targ_spec)
{
bool failed = false, validate = true;
__u32 orig_val, new_val;
struct bpf_insn *insn;
int insn_idx, err;
__u8 class;
if (relo->insn_off % sizeof(struct bpf_insn))
return -EINVAL;
insn_idx = relo->insn_off / sizeof(struct bpf_insn);
if (relo->kind == BPF_FIELD_EXISTS) {
orig_val = 1; /* can't generate EXISTS relo w/o local field */
new_val = targ_spec ? 1 : 0;
} else if (!targ_spec) {
failed = true;
new_val = (__u32)-1;
} else {
err = bpf_core_calc_field_relo(prog, relo, local_spec,
&orig_val, &validate);
if (err)
return err;
err = bpf_core_calc_field_relo(prog, relo, targ_spec,
&new_val, NULL);
if (err)
return err;
}
insn = &prog->insns[insn_idx];
class = BPF_CLASS(insn->code);
if (class == BPF_ALU || class == BPF_ALU64) {
if (BPF_SRC(insn->code) != BPF_K)
return -EINVAL;
if (!failed && validate && insn->imm != orig_val) {
pr_warn("prog '%s': unexpected insn #%d value: got %u, exp %u -> %u\n",
bpf_program__title(prog, false), insn_idx,
insn->imm, orig_val, new_val);
return -EINVAL;
}
orig_val = insn->imm;
insn->imm = new_val;
pr_debug("prog '%s': patched insn #%d (ALU/ALU64)%s imm %u -> %u\n",
bpf_program__title(prog, false), insn_idx,
failed ? " w/ failed reloc" : "", orig_val, new_val);
} else {
pr_warn("prog '%s': trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
bpf_program__title(prog, false),
insn_idx, insn->code, insn->src_reg, insn->dst_reg,
insn->off, insn->imm);
return -EINVAL;
}
return 0;
}
static struct btf *btf_load_raw(const char *path)
{
struct btf *btf;
size_t read_cnt;
struct stat st;
void *data;
FILE *f;
if (stat(path, &st))
return ERR_PTR(-errno);
data = malloc(st.st_size);
if (!data)
return ERR_PTR(-ENOMEM);
f = fopen(path, "rb");
if (!f) {
btf = ERR_PTR(-errno);
goto cleanup;
}
read_cnt = fread(data, 1, st.st_size, f);
fclose(f);
if (read_cnt < st.st_size) {
btf = ERR_PTR(-EBADF);
goto cleanup;
}
btf = btf__new(data, read_cnt);
cleanup:
free(data);
return btf;
}
/*
* Probe few well-known locations for vmlinux kernel image and try to load BTF
* data out of it to use for target BTF.
*/
static struct btf *bpf_core_find_kernel_btf(void)
{
struct {
const char *path_fmt;
bool raw_btf;
} locations[] = {
/* try canonical vmlinux BTF through sysfs first */
{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
/* fall back to trying to find vmlinux ELF on disk otherwise */
{ "/boot/vmlinux-%1$s" },
{ "/lib/modules/%1$s/vmlinux-%1$s" },
{ "/lib/modules/%1$s/build/vmlinux" },
{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
{ "/usr/lib/debug/boot/vmlinux-%1$s" },
{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
};
char path[PATH_MAX + 1];
struct utsname buf;
struct btf *btf;
int i;
uname(&buf);
for (i = 0; i < ARRAY_SIZE(locations); i++) {
snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
if (access(path, R_OK))
continue;
if (locations[i].raw_btf)
btf = btf_load_raw(path);
else
btf = btf__parse_elf(path, NULL);
pr_debug("loading kernel BTF '%s': %ld\n",
path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
if (IS_ERR(btf))
continue;
return btf;
}
pr_warn("failed to find valid kernel BTF\n");
return ERR_PTR(-ESRCH);
}
/* Output spec definition in the format:
* [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
* where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
*/
static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
{
const struct btf_type *t;
const char *s;
__u32 type_id;
int i;
type_id = spec->spec[0].type_id;
t = btf__type_by_id(spec->btf, type_id);
s = btf__name_by_offset(spec->btf, t->name_off);
libbpf_print(level, "[%u] %s + ", type_id, s);
for (i = 0; i < spec->raw_len; i++)
libbpf_print(level, "%d%s", spec->raw_spec[i],
i == spec->raw_len - 1 ? " => " : ":");
libbpf_print(level, "%u.%u @ &x",
spec->bit_offset / 8, spec->bit_offset % 8);
for (i = 0; i < spec->len; i++) {
if (spec->spec[i].name)
libbpf_print(level, ".%s", spec->spec[i].name);
else
libbpf_print(level, "[%u]", spec->spec[i].idx);
}
}
static size_t bpf_core_hash_fn(const void *key, void *ctx)
{
return (size_t)key;
}
static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
{
return k1 == k2;
}
static void *u32_as_hash_key(__u32 x)
{
return (void *)(uintptr_t)x;
}
/*
* CO-RE relocate single instruction.
*
* The outline and important points of the algorithm:
* 1. For given local type, find corresponding candidate target types.
* Candidate type is a type with the same "essential" name, ignoring
* everything after last triple underscore (___). E.g., `sample`,
* `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
* for each other. Names with triple underscore are referred to as
* "flavors" and are useful, among other things, to allow to
* specify/support incompatible variations of the same kernel struct, which
* might differ between different kernel versions and/or build
* configurations.
*
* N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
* converter, when deduplicated BTF of a kernel still contains more than
* one different types with the same name. In that case, ___2, ___3, etc
* are appended starting from second name conflict. But start flavors are
* also useful to be defined "locally", in BPF program, to extract same
* data from incompatible changes between different kernel
* versions/configurations. For instance, to handle field renames between
* kernel versions, one can use two flavors of the struct name with the
* same common name and use conditional relocations to extract that field,
* depending on target kernel version.
* 2. For each candidate type, try to match local specification to this
* candidate target type. Matching involves finding corresponding
* high-level spec accessors, meaning that all named fields should match,
* as well as all array accesses should be within the actual bounds. Also,
* types should be compatible (see bpf_core_fields_are_compat for details).
* 3. It is supported and expected that there might be multiple flavors
* matching the spec. As long as all the specs resolve to the same set of
* offsets across all candidates, there is no error. If there is any
* ambiguity, CO-RE relocation will fail. This is necessary to accomodate
* imprefection of BTF deduplication, which can cause slight duplication of
* the same BTF type, if some directly or indirectly referenced (by
* pointer) type gets resolved to different actual types in different
* object files. If such situation occurs, deduplicated BTF will end up
* with two (or more) structurally identical types, which differ only in
* types they refer to through pointer. This should be OK in most cases and
* is not an error.
* 4. Candidate types search is performed by linearly scanning through all
* types in target BTF. It is anticipated that this is overall more
* efficient memory-wise and not significantly worse (if not better)
* CPU-wise compared to prebuilding a map from all local type names to
* a list of candidate type names. It's also sped up by caching resolved
* list of matching candidates per each local "root" type ID, that has at
* least one bpf_field_reloc associated with it. This list is shared
* between multiple relocations for the same type ID and is updated as some
* of the candidates are pruned due to structural incompatibility.
*/
static int bpf_core_reloc_field(struct bpf_program *prog,
const struct bpf_field_reloc *relo,
int relo_idx,
const struct btf *local_btf,
const struct btf *targ_btf,
struct hashmap *cand_cache)
{
const char *prog_name = bpf_program__title(prog, false);
struct bpf_core_spec local_spec, cand_spec, targ_spec;
const void *type_key = u32_as_hash_key(relo->type_id);
const struct btf_type *local_type, *cand_type;
const char *local_name, *cand_name;
struct ids_vec *cand_ids;
__u32 local_id, cand_id;
const char *spec_str;
int i, j, err;
local_id = relo->type_id;
local_type = btf__type_by_id(local_btf, local_id);
if (!local_type)
return -EINVAL;
local_name = btf__name_by_offset(local_btf, local_type->name_off);
if (str_is_empty(local_name))
return -EINVAL;
spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
if (str_is_empty(spec_str))
return -EINVAL;
err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
if (err) {
pr_warn("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
prog_name, relo_idx, local_id, local_name, spec_str,
err);
return -EINVAL;
}
pr_debug("prog '%s': relo #%d: kind %d, spec is ", prog_name, relo_idx,
relo->kind);
bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
libbpf_print(LIBBPF_DEBUG, "\n");
if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
if (IS_ERR(cand_ids)) {
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
prog_name, relo_idx, local_id, local_name,
PTR_ERR(cand_ids));
return PTR_ERR(cand_ids);
}
err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
if (err) {
bpf_core_free_cands(cand_ids);
return err;
}
}
for (i = 0, j = 0; i < cand_ids->len; i++) {
cand_id = cand_ids->data[i];
cand_type = btf__type_by_id(targ_btf, cand_id);
cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
err = bpf_core_spec_match(&local_spec, targ_btf,
cand_id, &cand_spec);
pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
prog_name, relo_idx, i, cand_name);
bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
if (err < 0) {
pr_warn("prog '%s': relo #%d: matching error: %d\n",
prog_name, relo_idx, err);
return err;
}
if (err == 0)
continue;
if (j == 0) {
targ_spec = cand_spec;
} else if (cand_spec.bit_offset != targ_spec.bit_offset) {
/* if there are many candidates, they should all
* resolve to the same bit offset
*/
pr_warn("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
prog_name, relo_idx, cand_spec.bit_offset,
targ_spec.bit_offset);
return -EINVAL;
}
cand_ids->data[j++] = cand_spec.spec[0].type_id;
}
/*
* For BPF_FIELD_EXISTS relo or when relaxed CO-RE reloc mode is
* requested, it's expected that we might not find any candidates.
* In this case, if field wasn't found in any candidate, the list of
* candidates shouldn't change at all, we'll just handle relocating
* appropriately, depending on relo's kind.
*/
if (j > 0)
cand_ids->len = j;
if (j == 0 && !prog->obj->relaxed_core_relocs &&
relo->kind != BPF_FIELD_EXISTS) {
pr_warn("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
prog_name, relo_idx, local_id, local_name, spec_str);
return -ESRCH;
}
/* bpf_core_reloc_insn should know how to handle missing targ_spec */
err = bpf_core_reloc_insn(prog, relo, &local_spec,
j ? &targ_spec : NULL);
if (err) {
pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
prog_name, relo_idx, relo->insn_off, err);
return -EINVAL;
}
return 0;
}
static int
bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
{
const struct btf_ext_info_sec *sec;
const struct bpf_field_reloc *rec;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct bpf_program *prog;
struct btf *targ_btf;
const char *sec_name;
int i, err = 0;
if (targ_btf_path)
targ_btf = btf__parse_elf(targ_btf_path, NULL);
else
targ_btf = bpf_core_find_kernel_btf();
if (IS_ERR(targ_btf)) {
pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
return PTR_ERR(targ_btf);
}
cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
if (IS_ERR(cand_cache)) {
err = PTR_ERR(cand_cache);
goto out;
}
seg = &obj->btf_ext->field_reloc_info;
for_each_btf_ext_sec(seg, sec) {
sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
if (str_is_empty(sec_name)) {
err = -EINVAL;
goto out;
}
prog = bpf_object__find_program_by_title(obj, sec_name);
if (!prog) {
pr_warn("failed to find program '%s' for CO-RE offset relocation\n",
sec_name);
err = -EINVAL;
goto out;
}
pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
sec_name, sec->num_info);
for_each_btf_ext_rec(seg, sec, i, rec) {
err = bpf_core_reloc_field(prog, rec, i, obj->btf,
targ_btf, cand_cache);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
sec_name, i, err);
goto out;
}
}
}
out:
btf__free(targ_btf);
if (!IS_ERR_OR_NULL(cand_cache)) {
hashmap__for_each_entry(cand_cache, entry, i) {
bpf_core_free_cands(entry->value);
}
hashmap__free(cand_cache);
}
return err;
}
static int
bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
{
int err = 0;
if (obj->btf_ext->field_reloc_info.len)
err = bpf_core_reloc_fields(obj, targ_btf_path);
return err;
}
static int
bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
struct reloc_desc *relo)
{
struct bpf_insn *insn, *new_insn;
struct bpf_program *text;
size_t new_cnt;
int err;
if (relo->type != RELO_CALL)
return -LIBBPF_ERRNO__RELOC;
if (prog->idx == obj->efile.text_shndx) {
pr_warn("relo in .text insn %d into off %d\n",
relo->insn_idx, relo->text_off);
return -LIBBPF_ERRNO__RELOC;
}
if (prog->main_prog_cnt == 0) {
text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
if (!text) {
pr_warn("no .text section found yet relo into text exist\n");
return -LIBBPF_ERRNO__RELOC;
}
new_cnt = prog->insns_cnt + text->insns_cnt;
new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
if (!new_insn) {
pr_warn("oom in prog realloc\n");
return -ENOMEM;
}
prog->insns = new_insn;
if (obj->btf_ext) {
err = bpf_program_reloc_btf_ext(prog, obj,
text->section_name,
prog->insns_cnt);
if (err)
return err;
}
memcpy(new_insn + prog->insns_cnt, text->insns,
text->insns_cnt * sizeof(*insn));
prog->main_prog_cnt = prog->insns_cnt;
prog->insns_cnt = new_cnt;
pr_debug("added %zd insn from %s to prog %s\n",
text->insns_cnt, text->section_name,
prog->section_name);
}
insn = &prog->insns[relo->insn_idx];
insn->imm += prog->main_prog_cnt - relo->insn_idx;
return 0;
}
static int
bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
{
int i, err;
if (!prog)
return 0;
if (obj->btf_ext) {
err = bpf_program_reloc_btf_ext(prog, obj,
prog->section_name, 0);
if (err)
return err;
}
if (!prog->reloc_desc)
return 0;
for (i = 0; i < prog->nr_reloc; i++) {
if (prog->reloc_desc[i].type == RELO_LD64 ||
prog->reloc_desc[i].type == RELO_DATA) {
bool relo_data = prog->reloc_desc[i].type == RELO_DATA;
struct bpf_insn *insns = prog->insns;
int insn_idx, map_idx;
insn_idx = prog->reloc_desc[i].insn_idx;
map_idx = prog->reloc_desc[i].map_idx;
if (insn_idx + 1 >= (int)prog->insns_cnt) {
pr_warn("relocation out of range: '%s'\n",
prog->section_name);
return -LIBBPF_ERRNO__RELOC;
}
if (!relo_data) {
insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
} else {
insns[insn_idx].src_reg = BPF_PSEUDO_MAP_VALUE;
insns[insn_idx + 1].imm = insns[insn_idx].imm;
}
insns[insn_idx].imm = obj->maps[map_idx].fd;
} else if (prog->reloc_desc[i].type == RELO_CALL) {
err = bpf_program__reloc_text(prog, obj,
&prog->reloc_desc[i]);
if (err)
return err;
}
}
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
return 0;
}
static int
bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
{
struct bpf_program *prog;
size_t i;
int err;
if (obj->btf_ext) {
err = bpf_object__relocate_core(obj, targ_btf_path);
if (err) {
pr_warn("failed to perform CO-RE relocations: %d\n",
err);
return err;
}
}
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
err = bpf_program__relocate(prog, obj);
if (err) {
pr_warn("failed to relocate '%s'\n", prog->section_name);
return err;
}
}
return 0;
}
static int bpf_object__collect_reloc(struct bpf_object *obj)
{
int i, err;
if (!obj_elf_valid(obj)) {
pr_warn("Internal error: elf object is closed\n");
return -LIBBPF_ERRNO__INTERNAL;
}
for (i = 0; i < obj->efile.nr_reloc; i++) {
GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
Elf_Data *data = obj->efile.reloc[i].data;
int idx = shdr->sh_info;
struct bpf_program *prog;
if (shdr->sh_type != SHT_REL) {
pr_warn("internal error at %d\n", __LINE__);
return -LIBBPF_ERRNO__INTERNAL;
}
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warn("relocation failed: no section(%d)\n", idx);
return -LIBBPF_ERRNO__RELOC;
}
err = bpf_program__collect_reloc(prog, shdr, data, obj);
if (err)
return err;
}
return 0;
}
static int
load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *license, __u32 kern_version, int *pfd)
{
struct bpf_load_program_attr load_attr;
char *cp, errmsg[STRERR_BUFSIZE];
int log_buf_size = BPF_LOG_BUF_SIZE;
char *log_buf;
int btf_fd, ret;
if (!insns || !insns_cnt)
return -EINVAL;
memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = prog->type;
load_attr.expected_attach_type = prog->expected_attach_type;
if (prog->caps->name)
load_attr.name = prog->name;
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = license;
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
/* if .BTF.ext was loaded, kernel supports associated BTF for prog */
if (prog->obj->btf_ext)
btf_fd = bpf_object__btf_fd(prog->obj);
else
btf_fd = -1;
load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
load_attr.func_info = prog->func_info;
load_attr.func_info_rec_size = prog->func_info_rec_size;
load_attr.func_info_cnt = prog->func_info_cnt;
load_attr.line_info = prog->line_info;
load_attr.line_info_rec_size = prog->line_info_rec_size;
load_attr.line_info_cnt = prog->line_info_cnt;
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
load_attr.attach_btf_id = prog->attach_btf_id;
retry_load:
log_buf = malloc(log_buf_size);
if (!log_buf)
pr_warn("Alloc log buffer for bpf loader error, continue without log\n");
ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
if (ret >= 0) {
if (load_attr.log_level)
pr_debug("verifier log:\n%s", log_buf);
*pfd = ret;
ret = 0;
goto out;
}
if (errno == ENOSPC) {
log_buf_size <<= 1;
free(log_buf);
goto retry_load;
}
ret = -errno;
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("load bpf program failed: %s\n", cp);
if (log_buf && log_buf[0] != '\0') {
ret = -LIBBPF_ERRNO__VERIFY;
pr_warn("-- BEGIN DUMP LOG ---\n");
pr_warn("\n%s\n", log_buf);
pr_warn("-- END LOG --\n");
} else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
pr_warn("Program too large (%zu insns), at most %d insns\n",
load_attr.insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
int fd;
load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
load_attr.expected_attach_type = 0;
fd = bpf_load_program_xattr(&load_attr, NULL, 0);
if (fd >= 0) {
close(fd);
ret = -LIBBPF_ERRNO__PROGTYPE;
goto out;
}
}
out:
free(log_buf);
return ret;
}
int
bpf_program__load(struct bpf_program *prog,
char *license, __u32 kern_version)
{
int err = 0, fd, i;
if (prog->instances.nr < 0 || !prog->instances.fds) {
if (prog->preprocessor) {
pr_warn("Internal error: can't load program '%s'\n",
prog->section_name);
return -LIBBPF_ERRNO__INTERNAL;
}
prog->instances.fds = malloc(sizeof(int));
if (!prog->instances.fds) {
pr_warn("Not enough memory for BPF fds\n");
return -ENOMEM;
}
prog->instances.nr = 1;
prog->instances.fds[0] = -1;
}
if (!prog->preprocessor) {
if (prog->instances.nr != 1) {
pr_warn("Program '%s' is inconsistent: nr(%d) != 1\n",
prog->section_name, prog->instances.nr);
}
err = load_program(prog, prog->insns, prog->insns_cnt,
license, kern_version, &fd);
if (!err)
prog->instances.fds[0] = fd;
goto out;
}
for (i = 0; i < prog->instances.nr; i++) {
struct bpf_prog_prep_result result;
bpf_program_prep_t preprocessor = prog->preprocessor;
memset(&result, 0, sizeof(result));
err = preprocessor(prog, i, prog->insns,
prog->insns_cnt, &result);
if (err) {
pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
i, prog->section_name);
goto out;
}
if (!result.new_insn_ptr || !result.new_insn_cnt) {
pr_debug("Skip loading the %dth instance of program '%s'\n",
i, prog->section_name);
prog->instances.fds[i] = -1;
if (result.pfd)
*result.pfd = -1;
continue;
}
err = load_program(prog, result.new_insn_ptr,
result.new_insn_cnt,
license, kern_version, &fd);
if (err) {
pr_warn("Loading the %dth instance of program '%s' failed\n",
i, prog->section_name);
goto out;
}
if (result.pfd)
*result.pfd = fd;
prog->instances.fds[i] = fd;
}
out:
if (err)
pr_warn("failed to load program '%s'\n", prog->section_name);
zfree(&prog->insns);
prog->insns_cnt = 0;
return err;
}
static bool bpf_program__is_function_storage(const struct bpf_program *prog,
const struct bpf_object *obj)
{
return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
}
static int
bpf_object__load_progs(struct bpf_object *obj, int log_level)
{
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
if (bpf_program__is_function_storage(&obj->programs[i], obj))
continue;
obj->programs[i].log_level |= log_level;
err = bpf_program__load(&obj->programs[i],
obj->license,
obj->kern_version);
if (err)
return err;
}
return 0;
}
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id);
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
{
const char *pin_root_path;
struct bpf_program *prog;
struct bpf_object *obj;
const char *obj_name;
char tmp_name[64];
bool relaxed_maps;
int err;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warn("failed to init libelf for %s\n",
path ? : "(mem buf)");
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
if (!OPTS_VALID(opts, bpf_object_open_opts))
return ERR_PTR(-EINVAL);
obj_name = OPTS_GET(opts, object_name, path);
if (obj_buf) {
if (!obj_name) {
snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
(unsigned long)obj_buf,
(unsigned long)obj_buf_sz);
obj_name = tmp_name;
}
path = obj_name;
pr_debug("loading object '%s' from buffer\n", obj_name);
}
obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
if (IS_ERR(obj))
return obj;
obj->relaxed_core_relocs = OPTS_GET(opts, relaxed_core_relocs, false);
relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
CHECK_ERR(bpf_object__elf_init(obj), err, out);
CHECK_ERR(bpf_object__check_endianness(obj), err, out);
CHECK_ERR(bpf_object__probe_caps(obj), err, out);
CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps, pin_root_path),
err, out);
CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
bpf_object__elf_finish(obj);
bpf_object__for_each_program(prog, obj) {
enum bpf_prog_type prog_type;
enum bpf_attach_type attach_type;
__u32 btf_id;
err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
&attach_type);
if (err == -ESRCH)
/* couldn't guess, but user might manually specify */
continue;
if (err)
goto out;
bpf_program__set_type(prog, prog_type);
bpf_program__set_expected_attach_type(prog, attach_type);
if (prog_type == BPF_PROG_TYPE_TRACING) {
err = libbpf_attach_btf_id_by_name(prog->section_name, &btf_id);
if (err)
goto out;
prog->attach_btf_id = btf_id;
}
}
return obj;
out:
bpf_object__close(obj);
return ERR_PTR(err);
}
static struct bpf_object *
__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.relaxed_maps = flags & MAPS_RELAX_COMPAT,
);
/* param validation */
if (!attr->file)
return NULL;
pr_debug("loading %s\n", attr->file);
return __bpf_object__open(attr->file, NULL, 0, &opts);
}
struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
{
return __bpf_object__open_xattr(attr, 0);
}
struct bpf_object *bpf_object__open(const char *path)
{
struct bpf_object_open_attr attr = {
.file = path,
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
return bpf_object__open_xattr(&attr);
}
struct bpf_object *
bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts)
{
if (!path)
return ERR_PTR(-EINVAL);
pr_debug("loading %s\n", path);
return __bpf_object__open(path, NULL, 0, opts);
}
struct bpf_object *
bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
{
if (!obj_buf || obj_buf_sz == 0)
return ERR_PTR(-EINVAL);
return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
}
struct bpf_object *
bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
const char *name)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.object_name = name,
/* wrong default, but backwards-compatible */
.relaxed_maps = true,
);
/* returning NULL is wrong, but backwards-compatible */
if (!obj_buf || obj_buf_sz == 0)
return NULL;
return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts);
}
int bpf_object__unload(struct bpf_object *obj)
{
size_t i;
if (!obj)
return -EINVAL;
for (i = 0; i < obj->nr_maps; i++)
zclose(obj->maps[i].fd);
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
return 0;
}
int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
{
struct bpf_object *obj;
int err, i;
if (!attr)
return -EINVAL;
obj = attr->obj;
if (!obj)
return -EINVAL;
if (obj->loaded) {
pr_warn("object should not be loaded twice\n");
return -EINVAL;
}
obj->loaded = true;
CHECK_ERR(bpf_object__create_maps(obj), err, out);
CHECK_ERR(bpf_object__relocate(obj, attr->target_btf_path), err, out);
CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
return 0;
out:
/* unpin any maps that were auto-pinned during load */
for (i = 0; i < obj->nr_maps; i++)
if (obj->maps[i].pinned && !obj->maps[i].reused)
bpf_map__unpin(&obj->maps[i], NULL);
bpf_object__unload(obj);
pr_warn("failed to load object '%s'\n", obj->path);
return err;
}
int bpf_object__load(struct bpf_object *obj)
{
struct bpf_object_load_attr attr = {
.obj = obj,
};
return bpf_object__load_xattr(&attr);
}
static int make_parent_dir(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
char *dname, *dir;
int err = 0;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (mkdir(dir, 0700) && errno != EEXIST)
err = -errno;
free(dname);
if (err) {
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to mkdir %s: %s\n", path, cp);
}
return err;
}
static int check_path(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
struct statfs st_fs;
char *dname, *dir;
int err = 0;
if (path == NULL)
return -EINVAL;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (statfs(dir, &st_fs)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("failed to statfs %s: %s\n", dir, cp);
err = -errno;
}
free(dname);
if (!err && st_fs.f_type != BPF_FS_MAGIC) {
pr_warn("specified path %s is not on BPF FS\n", path);
err = -EINVAL;
}
return err;
}
int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
int instance)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->section_name, prog->instances.nr);
return -EINVAL;
}
if (bpf_obj_pin(prog->instances.fds[instance], path)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("failed to pin program: %s\n", cp);
return -errno;
}
pr_debug("pinned program '%s'\n", path);
return 0;
}
int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
int instance)
{
int err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->section_name, prog->instances.nr);
return -EINVAL;
}
err = unlink(path);
if (err != 0)
return -errno;
pr_debug("unpinned program '%s'\n", path);
return 0;
}
int bpf_program__pin(struct bpf_program *prog, const char *path)
{
int i, err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n",
prog->section_name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__pin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0) {
err = -EINVAL;
goto err_unpin;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin;
}
err = bpf_program__pin_instance(prog, buf, i);
if (err)
goto err_unpin;
}
return 0;
err_unpin:
for (i = i - 1; i >= 0; i--) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin_instance(prog, buf, i);
}
rmdir(path);
return err;
}
int bpf_program__unpin(struct bpf_program *prog, const char *path)
{
int i, err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n",
prog->section_name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__unpin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin_instance(prog, buf, i);
if (err)
return err;
}
err = rmdir(path);
if (err)
return -errno;
return 0;
}
int bpf_map__pin(struct bpf_map *map, const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
} else if (map->pinned) {
pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
bpf_map__name(map), map->pin_path);
return 0;
}
} else {
if (!path) {
pr_warn("missing a path to pin map '%s' at\n",
bpf_map__name(map));
return -EINVAL;
} else if (map->pinned) {
pr_warn("map '%s' already pinned\n", bpf_map__name(map));
return -EEXIST;
}
map->pin_path = strdup(path);
if (!map->pin_path) {
err = -errno;
goto out_err;
}
}
err = make_parent_dir(map->pin_path);
if (err)
return err;
err = check_path(map->pin_path);
if (err)
return err;
if (bpf_obj_pin(map->fd, map->pin_path)) {
err = -errno;
goto out_err;
}
map->pinned = true;
pr_debug("pinned map '%s'\n", map->pin_path);
return 0;
out_err:
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to pin map: %s\n", cp);
return err;
}
int bpf_map__unpin(struct bpf_map *map, const char *path)
{
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
}
path = map->pin_path;
} else if (!path) {
pr_warn("no path to unpin map '%s' from\n",
bpf_map__name(map));
return -EINVAL;
}
err = check_path(path);
if (err)
return err;
err = unlink(path);
if (err != 0)
return -errno;
map->pinned = false;
pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
return 0;
}
int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
{
char *new = NULL;
if (path) {
new = strdup(path);
if (!new)
return -errno;
}
free(map->pin_path);
map->pin_path = new;
return 0;
}
const char *bpf_map__get_pin_path(const struct bpf_map *map)
{
return map->pin_path;
}
bool bpf_map__is_pinned(const struct bpf_map *map)
{
return map->pinned;
}
int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0) {
err = -EINVAL;
goto err_unpin_maps;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_maps;
}
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__pin(map, pin_path);
if (err)
goto err_unpin_maps;
}
return 0;
err_unpin_maps:
while ((map = bpf_map__prev(map, obj))) {
if (!map->pin_path)
continue;
bpf_map__unpin(map, NULL);
}
return err;
}
int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__unpin(map, pin_path);
if (err)
return err;
}
return 0;
}
int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0) {
err = -EINVAL;
goto err_unpin_programs;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_programs;
}
err = bpf_program__pin(prog, buf);
if (err)
goto err_unpin_programs;
}
return 0;
err_unpin_programs:
while ((prog = bpf_program__prev(prog, obj))) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin(prog, buf);
}
return err;
}
int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin(prog, buf);
if (err)
return err;
}
return 0;
}
int bpf_object__pin(struct bpf_object *obj, const char *path)
{
int err;
err = bpf_object__pin_maps(obj, path);
if (err)
return err;
err = bpf_object__pin_programs(obj, path);
if (err) {
bpf_object__unpin_maps(obj, path);
return err;
}
return 0;
}
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
if (!obj)
return;
if (obj->clear_priv)
obj->clear_priv(obj, obj->priv);
bpf_object__elf_finish(obj);
bpf_object__unload(obj);
btf__free(obj->btf);
btf_ext__free(obj->btf_ext);
for (i = 0; i < obj->nr_maps; i++) {
zfree(&obj->maps[i].name);
zfree(&obj->maps[i].pin_path);
if (obj->maps[i].clear_priv)
obj->maps[i].clear_priv(&obj->maps[i],
obj->maps[i].priv);
obj->maps[i].priv = NULL;
obj->maps[i].clear_priv = NULL;
}
zfree(&obj->sections.rodata);
zfree(&obj->sections.data);
zfree(&obj->maps);
obj->nr_maps = 0;
if (obj->programs && obj->nr_programs) {
for (i = 0; i < obj->nr_programs; i++)
bpf_program__exit(&obj->programs[i]);
}
zfree(&obj->programs);
list_del(&obj->list);
free(obj);
}
struct bpf_object *
bpf_object__next(struct bpf_object *prev)
{
struct bpf_object *next;
if (!prev)
next = list_first_entry(&bpf_objects_list,
struct bpf_object,
list);
else
next = list_next_entry(prev, list);
/* Empty list is noticed here so don't need checking on entry. */
if (&next->list == &bpf_objects_list)
return NULL;
return next;
}
const char *bpf_object__name(const struct bpf_object *obj)
{
return obj ? obj->name : ERR_PTR(-EINVAL);
}
unsigned int bpf_object__kversion(const struct bpf_object *obj)
{
return obj ? obj->kern_version : 0;
}
struct btf *bpf_object__btf(const struct bpf_object *obj)
{
return obj ? obj->btf : NULL;
}
int bpf_object__btf_fd(const struct bpf_object *obj)
{
return obj->btf ? btf__fd(obj->btf) : -1;
}
int bpf_object__set_priv(struct bpf_object *obj, void *priv,
bpf_object_clear_priv_t clear_priv)
{
if (obj->priv && obj->clear_priv)
obj->clear_priv(obj, obj->priv);
obj->priv = priv;
obj->clear_priv = clear_priv;
return 0;
}
void *bpf_object__priv(const struct bpf_object *obj)
{
return obj ? obj->priv : ERR_PTR(-EINVAL);
}
static struct bpf_program *
__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
bool forward)
{
size_t nr_programs = obj->nr_programs;
ssize_t idx;
if (!nr_programs)
return NULL;
if (!p)
/* Iter from the beginning */
return forward ? &obj->programs[0] :
&obj->programs[nr_programs - 1];
if (p->obj != obj) {
pr_warn("error: program handler doesn't match object\n");
return NULL;
}
idx = (p - obj->programs) + (forward ? 1 : -1);
if (idx >= obj->nr_programs || idx < 0)
return NULL;
return &obj->programs[idx];
}
struct bpf_program *
bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
{
struct bpf_program *prog = prev;
do {
prog = __bpf_program__iter(prog, obj, true);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
}
struct bpf_program *
bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
{
struct bpf_program *prog = next;
do {
prog = __bpf_program__iter(prog, obj, false);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
}
int bpf_program__set_priv(struct bpf_program *prog, void *priv,
bpf_program_clear_priv_t clear_priv)
{
if (prog->priv && prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = priv;
prog->clear_priv = clear_priv;
return 0;
}
void *bpf_program__priv(const struct bpf_program *prog)
{
return prog ? prog->priv : ERR_PTR(-EINVAL);
}
void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
{
prog->prog_ifindex = ifindex;
}
const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
{
const char *title;
title = prog->section_name;
if (needs_copy) {
title = strdup(title);
if (!title) {
pr_warn("failed to strdup program title\n");
return ERR_PTR(-ENOMEM);
}
}
return title;
}
int bpf_program__fd(const struct bpf_program *prog)
{
return bpf_program__nth_fd(prog, 0);
}
int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
bpf_program_prep_t prep)
{
int *instances_fds;
if (nr_instances <= 0 || !prep)
return -EINVAL;
if (prog->instances.nr > 0 || prog->instances.fds) {
pr_warn("Can't set pre-processor after loading\n");
return -EINVAL;
}
instances_fds = malloc(sizeof(int) * nr_instances);
if (!instances_fds) {
pr_warn("alloc memory failed for fds\n");
return -ENOMEM;
}
/* fill all fd with -1 */
memset(instances_fds, -1, sizeof(int) * nr_instances);
prog->instances.nr = nr_instances;
prog->instances.fds = instances_fds;
prog->preprocessor = prep;
return 0;
}
int bpf_program__nth_fd(const struct bpf_program *prog, int n)
{
int fd;
if (!prog)
return -EINVAL;
if (n >= prog->instances.nr || n < 0) {
pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
n, prog->section_name, prog->instances.nr);
return -EINVAL;
}
fd = prog->instances.fds[n];
if (fd < 0) {
pr_warn("%dth instance of program '%s' is invalid\n",
n, prog->section_name);
return -ENOENT;
}
return fd;
}
enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
{
return prog->type;
}
void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
{
prog->type = type;
}
static bool bpf_program__is_type(const struct bpf_program *prog,
enum bpf_prog_type type)
{
return prog ? (prog->type == type) : false;
}
#define BPF_PROG_TYPE_FNS(NAME, TYPE) \
int bpf_program__set_##NAME(struct bpf_program *prog) \
{ \
if (!prog) \
return -EINVAL; \
bpf_program__set_type(prog, TYPE); \
return 0; \
} \
\
bool bpf_program__is_##NAME(const struct bpf_program *prog) \
{ \
return bpf_program__is_type(prog, TYPE); \
} \
BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog)
{
return prog->expected_attach_type;
}
void bpf_program__set_expected_attach_type(struct bpf_program *prog,
enum bpf_attach_type type)
{
prog->expected_attach_type = type;
}
#define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, btf, atype) \
{ string, sizeof(string) - 1, ptype, eatype, is_attachable, btf, atype }
/* Programs that can NOT be attached. */
#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
/* Programs that can be attached. */
#define BPF_APROG_SEC(string, ptype, atype) \
BPF_PROG_SEC_IMPL(string, ptype, 0, 1, 0, atype)
/* Programs that must specify expected attach type at load time. */
#define BPF_EAPROG_SEC(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
/* Programs that use BTF to identify attach point */
#define BPF_PROG_BTF(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 0, 1, 0)
/* Programs that can be attached but attach type can't be identified by section
* name. Kept for backward compatibility.
*/
#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
static const struct {
const char *sec;
size_t len;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
bool is_attachable;
bool is_attach_btf;
enum bpf_attach_type attach_type;
} section_names[] = {
BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("tp/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_RAW_TP),
BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL),
BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_INGRESS),
BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_EGRESS),
BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET_SOCK_CREATE),
BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET4_POST_BIND),
BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET6_POST_BIND),
BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_CGROUP_DEVICE),
BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS,
BPF_CGROUP_SOCK_OPS),
BPF_APROG_SEC("sk_skb/stream_parser", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_PARSER),
BPF_APROG_SEC("sk_skb/stream_verdict", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_VERDICT),
BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB),
BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG,
BPF_SK_MSG_VERDICT),
BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2,
BPF_LIRC_MODE2),
BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_FLOW_DISSECTOR),
BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_BIND),
BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_BIND),
BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_CONNECT),
BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_CONNECT),
BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_SENDMSG),
BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_SENDMSG),
BPF_EAPROG_SEC("cgroup/recvmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_RECVMSG),
BPF_EAPROG_SEC("cgroup/recvmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_RECVMSG),
BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_CGROUP_SYSCTL),
BPF_EAPROG_SEC("cgroup/getsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_GETSOCKOPT),
BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_SETSOCKOPT),
};
#undef BPF_PROG_SEC_IMPL
#undef BPF_PROG_SEC
#undef BPF_APROG_SEC
#undef BPF_EAPROG_SEC
#undef BPF_APROG_COMPAT
#define MAX_TYPE_NAME_SIZE 32
static char *libbpf_get_type_names(bool attach_type)
{
int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;
char *buf;
buf = malloc(len);
if (!buf)
return NULL;
buf[0] = '\0';
/* Forge string buf with all available names */
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (attach_type && !section_names[i].is_attachable)
continue;
if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {
free(buf);
return NULL;
}
strcat(buf, " ");
strcat(buf, section_names[i].sec);
}
return buf;
}
int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type)
{
char *type_names;
int i;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
*prog_type = section_names[i].prog_type;
*expected_attach_type = section_names[i].expected_attach_type;
return 0;
}
pr_warn("failed to guess program type based on ELF section name '%s'\n", name);
type_names = libbpf_get_type_names(false);
if (type_names != NULL) {
pr_info("supported section(type) names are:%s\n", type_names);
free(type_names);
}
return -ESRCH;
}
#define BTF_PREFIX "btf_trace_"
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id)
{
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf_name[128] = BTF_PREFIX;
char *dst = raw_tp_btf_name + sizeof(BTF_PREFIX) - 1;
int ret, i, err = -EINVAL;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
if (!name)
goto out;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (!section_names[i].is_attach_btf)
continue;
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
sizeof(raw_tp_btf_name) - sizeof(BTF_PREFIX));
ret = btf__find_by_name(btf, raw_tp_btf_name);
if (ret <= 0) {
pr_warn("%s is not found in vmlinux BTF\n", dst);
goto out;
}
*btf_id = ret;
err = 0;
goto out;
}
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
err = -ESRCH;
out:
btf__free(btf);
return err;
}
int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type)
{
char *type_names;
int i;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
if (!section_names[i].is_attachable)
return -EINVAL;
*attach_type = section_names[i].attach_type;
return 0;
}
pr_warn("failed to guess attach type based on ELF section name '%s'\n", name);
type_names = libbpf_get_type_names(true);
if (type_names != NULL) {
pr_info("attachable section(type) names are:%s\n", type_names);
free(type_names);
}
return -EINVAL;
}
int bpf_map__fd(const struct bpf_map *map)
{
return map ? map->fd : -EINVAL;
}
const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
{
return map ? &map->def : ERR_PTR(-EINVAL);
}
const char *bpf_map__name(const struct bpf_map *map)
{
return map ? map->name : NULL;
}
__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
{
return map ? map->btf_key_type_id : 0;
}
__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
{
return map ? map->btf_value_type_id : 0;
}
int bpf_map__set_priv(struct bpf_map *map, void *priv,
bpf_map_clear_priv_t clear_priv)
{
if (!map)
return -EINVAL;
if (map->priv) {
if (map->clear_priv)
map->clear_priv(map, map->priv);
}
map->priv = priv;
map->clear_priv = clear_priv;
return 0;
}
void *bpf_map__priv(const struct bpf_map *map)
{
return map ? map->priv : ERR_PTR(-EINVAL);
}
bool bpf_map__is_offload_neutral(const struct bpf_map *map)
{
return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
}
bool bpf_map__is_internal(const struct bpf_map *map)
{
return map->libbpf_type != LIBBPF_MAP_UNSPEC;
}
void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
{
map->map_ifindex = ifindex;
}
int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
{
if (!bpf_map_type__is_map_in_map(map->def.type)) {
pr_warn("error: unsupported map type\n");
return -EINVAL;
}
if (map->inner_map_fd != -1) {
pr_warn("error: inner_map_fd already specified\n");
return -EINVAL;
}
map->inner_map_fd = fd;
return 0;
}
static struct bpf_map *
__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
{
ssize_t idx;
struct bpf_map *s, *e;
if (!obj || !obj->maps)
return NULL;
s = obj->maps;
e = obj->maps + obj->nr_maps;
if ((m < s) || (m >= e)) {
pr_warn("error in %s: map handler doesn't belong to object\n",
__func__);
return NULL;
}
idx = (m - obj->maps) + i;
if (idx >= obj->nr_maps || idx < 0)
return NULL;
return &obj->maps[idx];
}
struct bpf_map *
bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
{
if (prev == NULL)
return obj->maps;
return __bpf_map__iter(prev, obj, 1);
}
struct bpf_map *
bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
{
if (next == NULL) {
if (!obj->nr_maps)
return NULL;
return obj->maps + obj->nr_maps - 1;
}
return __bpf_map__iter(next, obj, -1);
}
struct bpf_map *
bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
{
struct bpf_map *pos;
bpf_object__for_each_map(pos, obj) {
if (pos->name && !strcmp(pos->name, name))
return pos;
}
return NULL;
}
int
bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
{
return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
}
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
{
return ERR_PTR(-ENOTSUP);
}
long libbpf_get_error(const void *ptr)
{
return PTR_ERR_OR_ZERO(ptr);
}
int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_prog_load_attr attr;
memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
attr.file = file;
attr.prog_type = type;
attr.expected_attach_type = 0;
return bpf_prog_load_xattr(&attr, pobj, prog_fd);
}
int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_object_open_attr open_attr = {};
struct bpf_program *prog, *first_prog = NULL;
struct bpf_object *obj;
struct bpf_map *map;
int err;
if (!attr)
return -EINVAL;
if (!attr->file)
return -EINVAL;
open_attr.file = attr->file;
open_attr.prog_type = attr->prog_type;
obj = bpf_object__open_xattr(&open_attr);
if (IS_ERR_OR_NULL(obj))
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
enum bpf_attach_type attach_type = attr->expected_attach_type;
/*
* to preserve backwards compatibility, bpf_prog_load treats
* attr->prog_type, if specified, as an override to whatever
* bpf_object__open guessed
*/
if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
bpf_program__set_type(prog, attr->prog_type);
bpf_program__set_expected_attach_type(prog,
attach_type);
}
if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
/*
* we haven't guessed from section name and user
* didn't provide a fallback type, too bad...
*/
bpf_object__close(obj);
return -EINVAL;
}
prog->prog_ifindex = attr->ifindex;
prog->log_level = attr->log_level;
prog->prog_flags = attr->prog_flags;
if (!first_prog)
first_prog = prog;
}
bpf_object__for_each_map(map, obj) {
if (!bpf_map__is_offload_neutral(map))
map->map_ifindex = attr->ifindex;
}
if (!first_prog) {
pr_warn("object file doesn't contain bpf program\n");
bpf_object__close(obj);
return -ENOENT;
}
err = bpf_object__load(obj);
if (err) {
bpf_object__close(obj);
return -EINVAL;
}
*pobj = obj;
*prog_fd = bpf_program__fd(first_prog);
return 0;
}
struct bpf_link {
int (*destroy)(struct bpf_link *link);
};
int bpf_link__destroy(struct bpf_link *link)
{
int err;
if (!link)
return 0;
err = link->destroy(link);
free(link);
return err;
}
struct bpf_link_fd {
struct bpf_link link; /* has to be at the top of struct */
int fd; /* hook FD */
};
static int bpf_link__destroy_perf_event(struct bpf_link *link)
{
struct bpf_link_fd *l = (void *)link;
int err;
err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
if (err)
err = -errno;
close(l->fd);
return err;
}
struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
int pfd)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, err;
if (pfd < 0) {
pr_warn("program '%s': invalid perf event FD %d\n",
bpf_program__title(prog, false), pfd);
return ERR_PTR(-EINVAL);
}
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
bpf_program__title(prog, false));
return ERR_PTR(-EINVAL);
}
link = malloc(sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->link.destroy = &bpf_link__destroy_perf_event;
link->fd = pfd;
if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
err = -errno;
free(link);
pr_warn("program '%s': failed to attach to pfd %d: %s\n",
bpf_program__title(prog, false), pfd,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
free(link);
pr_warn("program '%s': failed to enable pfd %d: %s\n",
bpf_program__title(prog, false), pfd,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
return (struct bpf_link *)link;
}
/*
* this function is expected to parse integer in the range of [0, 2^31-1] from
* given file using scanf format string fmt. If actual parsed value is
* negative, the result might be indistinguishable from error
*/
static int parse_uint_from_file(const char *file, const char *fmt)
{
char buf[STRERR_BUFSIZE];
int err, ret;
FILE *f;
f = fopen(file, "r");
if (!f) {
err = -errno;
pr_debug("failed to open '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
return err;
}
err = fscanf(f, fmt, &ret);
if (err != 1) {
err = err == EOF ? -EIO : -errno;
pr_debug("failed to parse '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
fclose(f);
return err;
}
fclose(f);
return ret;
}
static int determine_kprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_uprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_kprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int determine_uprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
uint64_t offset, int pid)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int type, pfd, err;
type = uprobe ? determine_uprobe_perf_type()
: determine_kprobe_perf_type();
if (type < 0) {
pr_warn("failed to determine %s perf type: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
return type;
}
if (retprobe) {
int bit = uprobe ? determine_uprobe_retprobe_bit()
: determine_kprobe_retprobe_bit();
if (bit < 0) {
pr_warn("failed to determine %s retprobe bit: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
return bit;
}
attr.config |= 1 << bit;
}
attr.size = sizeof(attr);
attr.type = type;
attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
attr.config2 = offset; /* kprobe_addr or probe_offset */
/* pid filter is meaningful only for uprobes */
pfd = syscall(__NR_perf_event_open, &attr,
pid < 0 ? -1 : pid /* pid */,
pid == -1 ? 0 : -1 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("%s perf_event_open() failed: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
bool retprobe,
const char *func_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
0 /* offset */, -1 /* pid */);
if (pfd < 0) {
pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
bpf_program__title(prog, false),
retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to %s '%s': %s\n",
bpf_program__title(prog, false),
retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
bool retprobe, pid_t pid,
const char *binary_path,
size_t func_offset)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(true /* uprobe */, retprobe,
binary_path, func_offset, pid);
if (pfd < 0) {
pr_warn("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
bpf_program__title(prog, false),
retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
bpf_program__title(prog, false),
retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static int determine_tracepoint_id(const char *tp_category,
const char *tp_name)
{
char file[PATH_MAX];
int ret;
ret = snprintf(file, sizeof(file),
"/sys/kernel/debug/tracing/events/%s/%s/id",
tp_category, tp_name);
if (ret < 0)
return -errno;
if (ret >= sizeof(file)) {
pr_debug("tracepoint %s/%s path is too long\n",
tp_category, tp_name);
return -E2BIG;
}
return parse_uint_from_file(file, "%d\n");
}
static int perf_event_open_tracepoint(const char *tp_category,
const char *tp_name)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int tp_id, pfd, err;
tp_id = determine_tracepoint_id(tp_category, tp_name);
if (tp_id < 0) {
pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
tp_category, tp_name,
libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
return tp_id;
}
attr.type = PERF_TYPE_TRACEPOINT;
attr.size = sizeof(attr);
attr.config = tp_id;
pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_tracepoint(tp_category, tp_name);
if (pfd < 0) {
pr_warn("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
bpf_program__title(prog, false),
tp_category, tp_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
bpf_program__title(prog, false),
tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static int bpf_link__destroy_fd(struct bpf_link *link)
{
struct bpf_link_fd *l = (void *)link;
return close(l->fd);
}
struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("program '%s': can't attach before loaded\n",
bpf_program__title(prog, false));
return ERR_PTR(-EINVAL);
}
link = malloc(sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->link.destroy = &bpf_link__destroy_fd;
pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warn("program '%s': failed to attach to raw tracepoint '%s': %s\n",
bpf_program__title(prog, false), tp_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link->fd = pfd;
return (struct bpf_link *)link;
}
enum bpf_perf_event_ret
bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
void **copy_mem, size_t *copy_size,
bpf_perf_event_print_t fn, void *private_data)
{
struct perf_event_mmap_page *header = mmap_mem;
__u64 data_head = ring_buffer_read_head(header);
__u64 data_tail = header->data_tail;
void *base = ((__u8 *)header) + page_size;
int ret = LIBBPF_PERF_EVENT_CONT;
struct perf_event_header *ehdr;
size_t ehdr_size;
while (data_head != data_tail) {
ehdr = base + (data_tail & (mmap_size - 1));
ehdr_size = ehdr->size;
if (((void *)ehdr) + ehdr_size > base + mmap_size) {
void *copy_start = ehdr;
size_t len_first = base + mmap_size - copy_start;
size_t len_secnd = ehdr_size - len_first;
if (*copy_size < ehdr_size) {
free(*copy_mem);
*copy_mem = malloc(ehdr_size);
if (!*copy_mem) {
*copy_size = 0;
ret = LIBBPF_PERF_EVENT_ERROR;
break;
}
*copy_size = ehdr_size;
}
memcpy(*copy_mem, copy_start, len_first);
memcpy(*copy_mem + len_first, base, len_secnd);
ehdr = *copy_mem;
}
ret = fn(ehdr, private_data);
data_tail += ehdr_size;
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
}
ring_buffer_write_tail(header, data_tail);
return ret;
}
struct perf_buffer;
struct perf_buffer_params {
struct perf_event_attr *attr;
/* if event_cb is specified, it takes precendence */
perf_buffer_event_fn event_cb;
/* sample_cb and lost_cb are higher-level common-case callbacks */
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx;
int cpu_cnt;
int *cpus;
int *map_keys;
};
struct perf_cpu_buf {
struct perf_buffer *pb;
void *base; /* mmap()'ed memory */
void *buf; /* for reconstructing segmented data */
size_t buf_size;
int fd;
int cpu;
int map_key;
};
struct perf_buffer {
perf_buffer_event_fn event_cb;
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx; /* passed into callbacks */
size_t page_size;
size_t mmap_size;
struct perf_cpu_buf **cpu_bufs;
struct epoll_event *events;
int cpu_cnt;
int epoll_fd; /* perf event FD */
int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
};
static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
if (!cpu_buf)
return;
if (cpu_buf->base &&
munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
if (cpu_buf->fd >= 0) {
ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
close(cpu_buf->fd);
}
free(cpu_buf->buf);
free(cpu_buf);
}
void perf_buffer__free(struct perf_buffer *pb)
{
int i;
if (!pb)
return;
if (pb->cpu_bufs) {
for (i = 0; i < pb->cpu_cnt && pb->cpu_bufs[i]; i++) {
struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
perf_buffer__free_cpu_buf(pb, cpu_buf);
}
free(pb->cpu_bufs);
}
if (pb->epoll_fd >= 0)
close(pb->epoll_fd);
free(pb->events);
free(pb);
}
static struct perf_cpu_buf *
perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
int cpu, int map_key)
{
struct perf_cpu_buf *cpu_buf;
char msg[STRERR_BUFSIZE];
int err;
cpu_buf = calloc(1, sizeof(*cpu_buf));
if (!cpu_buf)
return ERR_PTR(-ENOMEM);
cpu_buf->pb = pb;
cpu_buf->cpu = cpu;
cpu_buf->map_key = map_key;
cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
-1, PERF_FLAG_FD_CLOEXEC);
if (cpu_buf->fd < 0) {
err = -errno;
pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
PROT_READ | PROT_WRITE, MAP_SHARED,
cpu_buf->fd, 0);
if (cpu_buf->base == MAP_FAILED) {
cpu_buf->base = NULL;
err = -errno;
pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
return cpu_buf;
error:
perf_buffer__free_cpu_buf(pb, cpu_buf);
return (struct perf_cpu_buf *)ERR_PTR(err);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p);
struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
const struct perf_buffer_opts *opts)
{
struct perf_buffer_params p = {};
struct perf_event_attr attr = { 0, };
attr.config = PERF_COUNT_SW_BPF_OUTPUT,
attr.type = PERF_TYPE_SOFTWARE;
attr.sample_type = PERF_SAMPLE_RAW;
attr.sample_period = 1;
attr.wakeup_events = 1;
p.attr = &attr;
p.sample_cb = opts ? opts->sample_cb : NULL;
p.lost_cb = opts ? opts->lost_cb : NULL;
p.ctx = opts ? opts->ctx : NULL;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
struct perf_buffer *
perf_buffer__new_raw(int map_fd, size_t page_cnt,
const struct perf_buffer_raw_opts *opts)
{
struct perf_buffer_params p = {};
p.attr = opts->attr;
p.event_cb = opts->event_cb;
p.ctx = opts->ctx;
p.cpu_cnt = opts->cpu_cnt;
p.cpus = opts->cpus;
p.map_keys = opts->map_keys;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p)
{
struct bpf_map_info map = {};
char msg[STRERR_BUFSIZE];
struct perf_buffer *pb;
__u32 map_info_len;
int err, i;
if (page_cnt & (page_cnt - 1)) {
pr_warn("page count should be power of two, but is %zu\n",
page_cnt);
return ERR_PTR(-EINVAL);
}
map_info_len = sizeof(map);
err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
if (err) {
err = -errno;
pr_warn("failed to get map info for map FD %d: %s\n",
map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
return ERR_PTR(err);
}
if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
map.name);
return ERR_PTR(-EINVAL);
}
pb = calloc(1, sizeof(*pb));
if (!pb)
return ERR_PTR(-ENOMEM);
pb->event_cb = p->event_cb;
pb->sample_cb = p->sample_cb;
pb->lost_cb = p->lost_cb;
pb->ctx = p->ctx;
pb->page_size = getpagesize();
pb->mmap_size = pb->page_size * page_cnt;
pb->map_fd = map_fd;
pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
if (pb->epoll_fd < 0) {
err = -errno;
pr_warn("failed to create epoll instance: %s\n",
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (p->cpu_cnt > 0) {
pb->cpu_cnt = p->cpu_cnt;
} else {
pb->cpu_cnt = libbpf_num_possible_cpus();
if (pb->cpu_cnt < 0) {
err = pb->cpu_cnt;
goto error;
}
if (map.max_entries < pb->cpu_cnt)
pb->cpu_cnt = map.max_entries;
}
pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
if (!pb->events) {
err = -ENOMEM;
pr_warn("failed to allocate events: out of memory\n");
goto error;
}
pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
if (!pb->cpu_bufs) {
err = -ENOMEM;
pr_warn("failed to allocate buffers: out of memory\n");
goto error;
}
for (i = 0; i < pb->cpu_cnt; i++) {
struct perf_cpu_buf *cpu_buf;
int cpu, map_key;
cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
if (IS_ERR(cpu_buf)) {
err = PTR_ERR(cpu_buf);
goto error;
}
pb->cpu_bufs[i] = cpu_buf;
err = bpf_map_update_elem(pb->map_fd, &map_key,
&cpu_buf->fd, 0);
if (err) {
err = -errno;
pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
cpu, map_key, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
pb->events[i].events = EPOLLIN;
pb->events[i].data.ptr = cpu_buf;
if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
&pb->events[i]) < 0) {
err = -errno;
pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
cpu, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
}
return pb;
error:
if (pb)
perf_buffer__free(pb);
return ERR_PTR(err);
}
struct perf_sample_raw {
struct perf_event_header header;
uint32_t size;
char data[0];
};
struct perf_sample_lost {
struct perf_event_header header;
uint64_t id;
uint64_t lost;
uint64_t sample_id;
};
static enum bpf_perf_event_ret
perf_buffer__process_record(struct perf_event_header *e, void *ctx)
{
struct perf_cpu_buf *cpu_buf = ctx;
struct perf_buffer *pb = cpu_buf->pb;
void *data = e;
/* user wants full control over parsing perf event */
if (pb->event_cb)
return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
switch (e->type) {
case PERF_RECORD_SAMPLE: {
struct perf_sample_raw *s = data;
if (pb->sample_cb)
pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
break;
}
case PERF_RECORD_LOST: {
struct perf_sample_lost *s = data;
if (pb->lost_cb)
pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
break;
}
default:
pr_warn("unknown perf sample type %d\n", e->type);
return LIBBPF_PERF_EVENT_ERROR;
}
return LIBBPF_PERF_EVENT_CONT;
}
static int perf_buffer__process_records(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
enum bpf_perf_event_ret ret;
ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
pb->page_size, &cpu_buf->buf,
&cpu_buf->buf_size,
perf_buffer__process_record, cpu_buf);
if (ret != LIBBPF_PERF_EVENT_CONT)
return ret;
return 0;
}
int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
{
int i, cnt, err;
cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
for (i = 0; i < cnt; i++) {
struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
err = perf_buffer__process_records(pb, cpu_buf);
if (err) {
pr_warn("error while processing records: %d\n", err);
return err;
}
}
return cnt < 0 ? -errno : cnt;
}
struct bpf_prog_info_array_desc {
int array_offset; /* e.g. offset of jited_prog_insns */
int count_offset; /* e.g. offset of jited_prog_len */
int size_offset; /* > 0: offset of rec size,
* < 0: fix size of -size_offset
*/
};
static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
[BPF_PROG_INFO_JITED_INSNS] = {
offsetof(struct bpf_prog_info, jited_prog_insns),
offsetof(struct bpf_prog_info, jited_prog_len),
-1,
},
[BPF_PROG_INFO_XLATED_INSNS] = {
offsetof(struct bpf_prog_info, xlated_prog_insns),
offsetof(struct bpf_prog_info, xlated_prog_len),
-1,
},
[BPF_PROG_INFO_MAP_IDS] = {
offsetof(struct bpf_prog_info, map_ids),
offsetof(struct bpf_prog_info, nr_map_ids),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_JITED_KSYMS] = {
offsetof(struct bpf_prog_info, jited_ksyms),
offsetof(struct bpf_prog_info, nr_jited_ksyms),
-(int)sizeof(__u64),
},
[BPF_PROG_INFO_JITED_FUNC_LENS] = {
offsetof(struct bpf_prog_info, jited_func_lens),
offsetof(struct bpf_prog_info, nr_jited_func_lens),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_FUNC_INFO] = {
offsetof(struct bpf_prog_info, func_info),
offsetof(struct bpf_prog_info, nr_func_info),
offsetof(struct bpf_prog_info, func_info_rec_size),
},
[BPF_PROG_INFO_LINE_INFO] = {
offsetof(struct bpf_prog_info, line_info),
offsetof(struct bpf_prog_info, nr_line_info),
offsetof(struct bpf_prog_info, line_info_rec_size),
},
[BPF_PROG_INFO_JITED_LINE_INFO] = {
offsetof(struct bpf_prog_info, jited_line_info),
offsetof(struct bpf_prog_info, nr_jited_line_info),
offsetof(struct bpf_prog_info, jited_line_info_rec_size),
},
[BPF_PROG_INFO_PROG_TAGS] = {
offsetof(struct bpf_prog_info, prog_tags),
offsetof(struct bpf_prog_info, nr_prog_tags),
-(int)sizeof(__u8) * BPF_TAG_SIZE,
},
};
static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
return array[offset / sizeof(__u32)];
return -(int)offset;
}
static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
return array[offset / sizeof(__u64)];
return -(int)offset;
}
static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
__u32 val)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
array[offset / sizeof(__u32)] = val;
}
static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
__u64 val)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
array[offset / sizeof(__u64)] = val;
}
struct bpf_prog_info_linear *
bpf_program__get_prog_info_linear(int fd, __u64 arrays)
{
struct bpf_prog_info_linear *info_linear;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
__u32 data_len = 0;
int i, err;
void *ptr;
if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
return ERR_PTR(-EINVAL);
/* step 1: get array dimensions */
err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
return ERR_PTR(-EFAULT);
}
/* step 2: calculate total size of all arrays */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
bool include_array = (arrays & (1UL << i)) > 0;
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
desc = bpf_prog_info_array_desc + i;
/* kernel is too old to support this field */
if (info_len < desc->array_offset + sizeof(__u32) ||
info_len < desc->count_offset + sizeof(__u32) ||
(desc->size_offset > 0 && info_len < desc->size_offset))
include_array = false;
if (!include_array) {
arrays &= ~(1UL << i); /* clear the bit */
continue;
}
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
data_len += count * size;
}
/* step 3: allocate continuous memory */
data_len = roundup(data_len, sizeof(__u64));
info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
if (!info_linear)
return ERR_PTR(-ENOMEM);
/* step 4: fill data to info_linear->info */
info_linear->arrays = arrays;
memset(&info_linear->info, 0, sizeof(info));
ptr = info_linear->data;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->count_offset, count);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->size_offset, size);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset,
ptr_to_u64(ptr));
ptr += count * size;
}
/* step 5: call syscall again to get required arrays */
err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
free(info_linear);
return ERR_PTR(-EFAULT);
}
/* step 6: verify the data */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 v1, v2;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->count_offset);
if (v1 != v2)
pr_warn("%s: mismatch in element count\n", __func__);
v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->size_offset);
if (v1 != v2)
pr_warn("%s: mismatch in rec size\n", __func__);
}
/* step 7: update info_len and data_len */
info_linear->info_len = sizeof(struct bpf_prog_info);
info_linear->data_len = data_len;
return info_linear;
}
void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
addr = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
offs = addr - ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, offs);
}
}
void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
offs = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
addr = offs + ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, addr);
}
}
int libbpf_num_possible_cpus(void)
{
static const char *fcpu = "/sys/devices/system/cpu/possible";
int len = 0, n = 0, il = 0, ir = 0;
unsigned int start = 0, end = 0;
int tmp_cpus = 0;
static int cpus;
char buf[128];
int error = 0;
int fd = -1;
tmp_cpus = READ_ONCE(cpus);
if (tmp_cpus > 0)
return tmp_cpus;
fd = open(fcpu, O_RDONLY);
if (fd < 0) {
error = errno;
pr_warn("Failed to open file %s: %s\n", fcpu, strerror(error));
return -error;
}
len = read(fd, buf, sizeof(buf));
close(fd);
if (len <= 0) {
error = len ? errno : EINVAL;
pr_warn("Failed to read # of possible cpus from %s: %s\n",
fcpu, strerror(error));
return -error;
}
if (len == sizeof(buf)) {
pr_warn("File %s size overflow\n", fcpu);
return -EOVERFLOW;
}
buf[len] = '\0';
for (ir = 0, tmp_cpus = 0; ir <= len; ir++) {
/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
if (buf[ir] == ',' || buf[ir] == '\0') {
buf[ir] = '\0';
n = sscanf(&buf[il], "%u-%u", &start, &end);
if (n <= 0) {
pr_warn("Failed to get # CPUs from %s\n",
&buf[il]);
return -EINVAL;
} else if (n == 1) {
end = start;
}
tmp_cpus += end - start + 1;
il = ir + 1;
}
}
if (tmp_cpus <= 0) {
pr_warn("Invalid #CPUs %d from %s\n", tmp_cpus, fcpu);
return -EINVAL;
}
WRITE_ONCE(cpus, tmp_cpus);
return tmp_cpus;
}
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