linux-stable/tools/bpf/bpftool/struct_ops.c
Quentin Monnet 90040351a8 tools, bpftool: Clean subcommand help messages
This is a clean-up for the formatting of the do_help functions for
bpftool's subcommands. The following fixes are included:

- Do not use argv[-2] for "iter" help message, as the help is shown by
  default if no "iter" action is selected, resulting in messages looking
  like "./bpftool bpftool pin...".

- Do not print unused HELP_SPEC_PROGRAM in help message for "bpftool
  link".

- Andrii used argument indexing to avoid having multiple occurrences of
  bin_name and argv[-2] in the fprintf() for the help message, for
  "bpftool gen" and "bpftool link". Let's reuse this for all other help
  functions. We can remove up to thirty arguments for the "bpftool map"
  help message.

- Harmonise all functions, e.g. use ending quotes-comma on a separate
  line.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200523010751.23465-1-quentin@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-06-01 14:38:18 -07:00

603 lines
13 KiB
C

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2020 Facebook */
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <linux/err.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include "json_writer.h"
#include "main.h"
#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
static const struct btf_type *map_info_type;
static __u32 map_info_alloc_len;
static struct btf *btf_vmlinux;
static __s32 map_info_type_id;
struct res {
unsigned int nr_maps;
unsigned int nr_errs;
};
static const struct btf *get_btf_vmlinux(void)
{
if (btf_vmlinux)
return btf_vmlinux;
btf_vmlinux = libbpf_find_kernel_btf();
if (IS_ERR(btf_vmlinux))
p_err("struct_ops requires kernel CONFIG_DEBUG_INFO_BTF=y");
return btf_vmlinux;
}
static const char *get_kern_struct_ops_name(const struct bpf_map_info *info)
{
const struct btf *kern_btf;
const struct btf_type *t;
const char *st_ops_name;
kern_btf = get_btf_vmlinux();
if (IS_ERR(kern_btf))
return "<btf_vmlinux_not_found>";
t = btf__type_by_id(kern_btf, info->btf_vmlinux_value_type_id);
st_ops_name = btf__name_by_offset(kern_btf, t->name_off);
st_ops_name += strlen(STRUCT_OPS_VALUE_PREFIX);
return st_ops_name;
}
static __s32 get_map_info_type_id(void)
{
const struct btf *kern_btf;
if (map_info_type_id)
return map_info_type_id;
kern_btf = get_btf_vmlinux();
if (IS_ERR(kern_btf)) {
map_info_type_id = PTR_ERR(kern_btf);
return map_info_type_id;
}
map_info_type_id = btf__find_by_name_kind(kern_btf, "bpf_map_info",
BTF_KIND_STRUCT);
if (map_info_type_id < 0) {
p_err("can't find bpf_map_info from btf_vmlinux");
return map_info_type_id;
}
map_info_type = btf__type_by_id(kern_btf, map_info_type_id);
/* Ensure map_info_alloc() has at least what the bpftool needs */
map_info_alloc_len = map_info_type->size;
if (map_info_alloc_len < sizeof(struct bpf_map_info))
map_info_alloc_len = sizeof(struct bpf_map_info);
return map_info_type_id;
}
/* If the subcmd needs to print out the bpf_map_info,
* it should always call map_info_alloc to allocate
* a bpf_map_info object instead of allocating it
* on the stack.
*
* map_info_alloc() will take the running kernel's btf
* into account. i.e. it will consider the
* sizeof(struct bpf_map_info) of the running kernel.
*
* It will enable the "struct_ops" cmd to print the latest
* "struct bpf_map_info".
*
* [ Recall that "struct_ops" requires the kernel's btf to
* be available ]
*/
static struct bpf_map_info *map_info_alloc(__u32 *alloc_len)
{
struct bpf_map_info *info;
if (get_map_info_type_id() < 0)
return NULL;
info = calloc(1, map_info_alloc_len);
if (!info)
p_err("mem alloc failed");
else
*alloc_len = map_info_alloc_len;
return info;
}
/* It iterates all struct_ops maps of the system.
* It returns the fd in "*res_fd" and map_info in "*info".
* In the very first iteration, info->id should be 0.
* An optional map "*name" filter can be specified.
* The filter can be made more flexible in the future.
* e.g. filter by kernel-struct-ops-name, regex-name, glob-name, ...etc.
*
* Return value:
* 1: A struct_ops map found. It is returned in "*res_fd" and "*info".
* The caller can continue to call get_next in the future.
* 0: No struct_ops map is returned.
* All struct_ops map has been found.
* -1: Error and the caller should abort the iteration.
*/
static int get_next_struct_ops_map(const char *name, int *res_fd,
struct bpf_map_info *info, __u32 info_len)
{
__u32 id = info->id;
int err, fd;
while (true) {
err = bpf_map_get_next_id(id, &id);
if (err) {
if (errno == ENOENT)
return 0;
p_err("can't get next map: %s", strerror(errno));
return -1;
}
fd = bpf_map_get_fd_by_id(id);
if (fd < 0) {
if (errno == ENOENT)
continue;
p_err("can't get map by id (%u): %s",
id, strerror(errno));
return -1;
}
err = bpf_obj_get_info_by_fd(fd, info, &info_len);
if (err) {
p_err("can't get map info: %s", strerror(errno));
close(fd);
return -1;
}
if (info->type == BPF_MAP_TYPE_STRUCT_OPS &&
(!name || !strcmp(name, info->name))) {
*res_fd = fd;
return 1;
}
close(fd);
}
}
static int cmd_retval(const struct res *res, bool must_have_one_map)
{
if (res->nr_errs || (!res->nr_maps && must_have_one_map))
return -1;
return 0;
}
/* "data" is the work_func private storage */
typedef int (*work_func)(int fd, const struct bpf_map_info *info, void *data,
struct json_writer *wtr);
/* Find all struct_ops map in the system.
* Filter out by "name" (if specified).
* Then call "func(fd, info, data, wtr)" on each struct_ops map found.
*/
static struct res do_search(const char *name, work_func func, void *data,
struct json_writer *wtr)
{
struct bpf_map_info *info;
struct res res = {};
__u32 info_len;
int fd, err;
info = map_info_alloc(&info_len);
if (!info) {
res.nr_errs++;
return res;
}
if (wtr)
jsonw_start_array(wtr);
while ((err = get_next_struct_ops_map(name, &fd, info, info_len)) == 1) {
res.nr_maps++;
err = func(fd, info, data, wtr);
if (err)
res.nr_errs++;
close(fd);
}
if (wtr)
jsonw_end_array(wtr);
if (err)
res.nr_errs++;
if (!wtr && name && !res.nr_errs && !res.nr_maps)
/* It is not printing empty [].
* Thus, needs to specifically say nothing found
* for "name" here.
*/
p_err("no struct_ops found for %s", name);
else if (!wtr && json_output && !res.nr_errs)
/* The "func()" above is not writing any json (i.e. !wtr
* test here).
*
* However, "-j" is enabled and there is no errs here,
* so call json_null() as the current convention of
* other cmds.
*/
jsonw_null(json_wtr);
free(info);
return res;
}
static struct res do_one_id(const char *id_str, work_func func, void *data,
struct json_writer *wtr)
{
struct bpf_map_info *info;
struct res res = {};
unsigned long id;
__u32 info_len;
char *endptr;
int fd;
id = strtoul(id_str, &endptr, 0);
if (*endptr || !id || id > UINT32_MAX) {
p_err("invalid id %s", id_str);
res.nr_errs++;
return res;
}
fd = bpf_map_get_fd_by_id(id);
if (fd == -1) {
p_err("can't get map by id (%lu): %s", id, strerror(errno));
res.nr_errs++;
return res;
}
info = map_info_alloc(&info_len);
if (!info) {
res.nr_errs++;
goto done;
}
if (bpf_obj_get_info_by_fd(fd, info, &info_len)) {
p_err("can't get map info: %s", strerror(errno));
res.nr_errs++;
goto done;
}
if (info->type != BPF_MAP_TYPE_STRUCT_OPS) {
p_err("%s id %u is not a struct_ops map", info->name, info->id);
res.nr_errs++;
goto done;
}
res.nr_maps++;
if (func(fd, info, data, wtr))
res.nr_errs++;
else if (!wtr && json_output)
/* The "func()" above is not writing any json (i.e. !wtr
* test here).
*
* However, "-j" is enabled and there is no errs here,
* so call json_null() as the current convention of
* other cmds.
*/
jsonw_null(json_wtr);
done:
free(info);
close(fd);
return res;
}
static struct res do_work_on_struct_ops(const char *search_type,
const char *search_term,
work_func func, void *data,
struct json_writer *wtr)
{
if (search_type) {
if (is_prefix(search_type, "id"))
return do_one_id(search_term, func, data, wtr);
else if (!is_prefix(search_type, "name"))
usage();
}
return do_search(search_term, func, data, wtr);
}
static int __do_show(int fd, const struct bpf_map_info *info, void *data,
struct json_writer *wtr)
{
if (wtr) {
jsonw_start_object(wtr);
jsonw_uint_field(wtr, "id", info->id);
jsonw_string_field(wtr, "name", info->name);
jsonw_string_field(wtr, "kernel_struct_ops",
get_kern_struct_ops_name(info));
jsonw_end_object(wtr);
} else {
printf("%u: %-15s %-32s\n", info->id, info->name,
get_kern_struct_ops_name(info));
}
return 0;
}
static int do_show(int argc, char **argv)
{
const char *search_type = NULL, *search_term = NULL;
struct res res;
if (argc && argc != 2)
usage();
if (argc == 2) {
search_type = GET_ARG();
search_term = GET_ARG();
}
res = do_work_on_struct_ops(search_type, search_term, __do_show,
NULL, json_wtr);
return cmd_retval(&res, !!search_term);
}
static int __do_dump(int fd, const struct bpf_map_info *info, void *data,
struct json_writer *wtr)
{
struct btf_dumper *d = (struct btf_dumper *)data;
const struct btf_type *struct_ops_type;
const struct btf *kern_btf = d->btf;
const char *struct_ops_name;
int zero = 0;
void *value;
/* note: d->jw == wtr */
kern_btf = d->btf;
/* The kernel supporting BPF_MAP_TYPE_STRUCT_OPS must have
* btf_vmlinux_value_type_id.
*/
struct_ops_type = btf__type_by_id(kern_btf,
info->btf_vmlinux_value_type_id);
struct_ops_name = btf__name_by_offset(kern_btf,
struct_ops_type->name_off);
value = calloc(1, info->value_size);
if (!value) {
p_err("mem alloc failed");
return -1;
}
if (bpf_map_lookup_elem(fd, &zero, value)) {
p_err("can't lookup struct_ops map %s id %u",
info->name, info->id);
free(value);
return -1;
}
jsonw_start_object(wtr);
jsonw_name(wtr, "bpf_map_info");
btf_dumper_type(d, map_info_type_id, (void *)info);
jsonw_end_object(wtr);
jsonw_start_object(wtr);
jsonw_name(wtr, struct_ops_name);
btf_dumper_type(d, info->btf_vmlinux_value_type_id, value);
jsonw_end_object(wtr);
free(value);
return 0;
}
static int do_dump(int argc, char **argv)
{
const char *search_type = NULL, *search_term = NULL;
json_writer_t *wtr = json_wtr;
const struct btf *kern_btf;
struct btf_dumper d = {};
struct res res;
if (argc && argc != 2)
usage();
if (argc == 2) {
search_type = GET_ARG();
search_term = GET_ARG();
}
kern_btf = get_btf_vmlinux();
if (IS_ERR(kern_btf))
return -1;
if (!json_output) {
wtr = jsonw_new(stdout);
if (!wtr) {
p_err("can't create json writer");
return -1;
}
jsonw_pretty(wtr, true);
}
d.btf = kern_btf;
d.jw = wtr;
d.is_plain_text = !json_output;
d.prog_id_as_func_ptr = true;
res = do_work_on_struct_ops(search_type, search_term, __do_dump, &d,
wtr);
if (!json_output)
jsonw_destroy(&wtr);
return cmd_retval(&res, !!search_term);
}
static int __do_unregister(int fd, const struct bpf_map_info *info, void *data,
struct json_writer *wtr)
{
int zero = 0;
if (bpf_map_delete_elem(fd, &zero)) {
p_err("can't unload %s %s id %u: %s",
get_kern_struct_ops_name(info), info->name,
info->id, strerror(errno));
return -1;
}
p_info("Unregistered %s %s id %u",
get_kern_struct_ops_name(info), info->name,
info->id);
return 0;
}
static int do_unregister(int argc, char **argv)
{
const char *search_type, *search_term;
struct res res;
if (argc != 2)
usage();
search_type = GET_ARG();
search_term = GET_ARG();
res = do_work_on_struct_ops(search_type, search_term,
__do_unregister, NULL, NULL);
return cmd_retval(&res, true);
}
static int do_register(int argc, char **argv)
{
struct bpf_object_load_attr load_attr = {};
const struct bpf_map_def *def;
struct bpf_map_info info = {};
__u32 info_len = sizeof(info);
int nr_errs = 0, nr_maps = 0;
struct bpf_object *obj;
struct bpf_link *link;
struct bpf_map *map;
const char *file;
if (argc != 1)
usage();
file = GET_ARG();
obj = bpf_object__open(file);
if (IS_ERR_OR_NULL(obj))
return -1;
set_max_rlimit();
load_attr.obj = obj;
if (verifier_logs)
/* log_level1 + log_level2 + stats, but not stable UAPI */
load_attr.log_level = 1 + 2 + 4;
if (bpf_object__load_xattr(&load_attr)) {
bpf_object__close(obj);
return -1;
}
bpf_object__for_each_map(map, obj) {
def = bpf_map__def(map);
if (def->type != BPF_MAP_TYPE_STRUCT_OPS)
continue;
link = bpf_map__attach_struct_ops(map);
if (IS_ERR(link)) {
p_err("can't register struct_ops %s: %s",
bpf_map__name(map),
strerror(-PTR_ERR(link)));
nr_errs++;
continue;
}
nr_maps++;
bpf_link__disconnect(link);
bpf_link__destroy(link);
if (!bpf_obj_get_info_by_fd(bpf_map__fd(map), &info,
&info_len))
p_info("Registered %s %s id %u",
get_kern_struct_ops_name(&info),
bpf_map__name(map),
info.id);
else
/* Not p_err. The struct_ops was attached
* successfully.
*/
p_info("Registered %s but can't find id: %s",
bpf_map__name(map), strerror(errno));
}
bpf_object__close(obj);
if (nr_errs)
return -1;
if (!nr_maps) {
p_err("no struct_ops found in %s", file);
return -1;
}
if (json_output)
jsonw_null(json_wtr);
return 0;
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [STRUCT_OPS_MAP]\n"
" %1$s %2$s dump [STRUCT_OPS_MAP]\n"
" %1$s %2$s register OBJ\n"
" %1$s %2$s unregister STRUCT_OPS_MAP\n"
" %1$s %2$s help\n"
"\n"
" OPTIONS := { {-j|--json} [{-p|--pretty}] }\n"
" STRUCT_OPS_MAP := [ id STRUCT_OPS_MAP_ID | name STRUCT_OPS_MAP_NAME ]\n"
"",
bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "register", do_register },
{ "unregister", do_unregister },
{ "dump", do_dump },
{ "help", do_help },
{ 0 }
};
int do_struct_ops(int argc, char **argv)
{
int err;
err = cmd_select(cmds, argc, argv, do_help);
if (!IS_ERR(btf_vmlinux))
btf__free(btf_vmlinux);
return err;
}