linux-stable/tools/lib/bpf/libbpf.h

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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
bpf tools: Introduce 'bpf' library and add bpf feature check This is the first patch of libbpf. The goal of libbpf is to create a standard way for accessing eBPF object files. This patch creates 'Makefile' and 'Build' for it, allows 'make' to build libbpf.a and libbpf.so, 'make install' to put them into proper directories. Most part of Makefile is borrowed from traceevent. Before building, it checks the existence of libelf in Makefile, and deny to build if not found. Instead of throwing an error if libelf not found, the error raises in a phony target "elfdep". This design is to ensure 'make clean' still workable even if libelf is not found. Because libbpf requires 'kern_version' field set for 'union bpf_attr' (bpfdep" is used for that dependency), Kernel BPF API is also checked by intruducing a new feature check 'bpf' into tools/build/feature, which checks the existence and version of linux/bpf.h. When building libbpf, it searches that file from include/uapi/linux in kernel source tree (controlled by FEATURE_CHECK_CFLAGS-bpf). Since it searches kernel source tree it reside, installing of newest kernel headers is not required, except we are trying to port these files to an old kernel. To avoid checking that file when perf building, the newly introduced 'bpf' feature check doesn't added into FEATURE_TESTS and FEATURE_DISPLAY by default in tools/build/Makefile.feature, but added into libbpf's specific. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Bcc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-4-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-07-01 02:13:51 +00:00
/*
* 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.
*/
#ifndef __LIBBPF_LIBBPF_H
#define __LIBBPF_LIBBPF_H
bpf tools: Introduce 'bpf' library and add bpf feature check This is the first patch of libbpf. The goal of libbpf is to create a standard way for accessing eBPF object files. This patch creates 'Makefile' and 'Build' for it, allows 'make' to build libbpf.a and libbpf.so, 'make install' to put them into proper directories. Most part of Makefile is borrowed from traceevent. Before building, it checks the existence of libelf in Makefile, and deny to build if not found. Instead of throwing an error if libelf not found, the error raises in a phony target "elfdep". This design is to ensure 'make clean' still workable even if libelf is not found. Because libbpf requires 'kern_version' field set for 'union bpf_attr' (bpfdep" is used for that dependency), Kernel BPF API is also checked by intruducing a new feature check 'bpf' into tools/build/feature, which checks the existence and version of linux/bpf.h. When building libbpf, it searches that file from include/uapi/linux in kernel source tree (controlled by FEATURE_CHECK_CFLAGS-bpf). Since it searches kernel source tree it reside, installing of newest kernel headers is not required, except we are trying to port these files to an old kernel. To avoid checking that file when perf building, the newly introduced 'bpf' feature check doesn't added into FEATURE_TESTS and FEATURE_DISPLAY by default in tools/build/Makefile.feature, but added into libbpf's specific. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Bcc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-4-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-07-01 02:13:51 +00:00
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <sys/types.h> // for size_t
#include <linux/bpf.h>
bpf tools: Improve libbpf error reporting In this patch, a series of libbpf specific error numbers and libbpf_strerror() are introduced to help reporting errors. Functions are updated to pass correct the error number through the CHECK_ERR() macro. All users of bpf_object__open{_buffer}() and bpf_program__title() in perf are modified accordingly. In addition, due to the error codes changing, bpf__strerror_load() is also modified to use them. bpf__strerror_head() is also changed accordingly so it can parse libbpf errors. bpf_loader_strerror() is introduced for that purpose, and will be improved by the following patch. load_program() is improved not to dump log buffer if it is empty. log buffer is also used to deduce whether the error was caused by an invalid program or other problem. v1 -> v2: - Using macro for error code. - Fetch error message based on array index, eliminate for-loop. - Use log buffer to detect the reason of failure. 3 new error code are introduced to replace LIBBPF_ERRNO__LOAD. In v1: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_big_program.o ls event syntax error: './test_big_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP In v2: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Kernel verifier blocks program loading SKIP # perf record -e ./test_kversion_nomatch_program.o event syntax error: './test_kversion_nomatch_program.o' \___ Incorrect kernel version SKIP (Will be further improved by following patches) # perf record -e ./test_big_program.o event syntax error: './test_big_program.o' \___ Program too big SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-06 13:49:37 +00:00
#include "libbpf_common.h"
#ifdef __cplusplus
extern "C" {
#endif
bpf tools: Improve libbpf error reporting In this patch, a series of libbpf specific error numbers and libbpf_strerror() are introduced to help reporting errors. Functions are updated to pass correct the error number through the CHECK_ERR() macro. All users of bpf_object__open{_buffer}() and bpf_program__title() in perf are modified accordingly. In addition, due to the error codes changing, bpf__strerror_load() is also modified to use them. bpf__strerror_head() is also changed accordingly so it can parse libbpf errors. bpf_loader_strerror() is introduced for that purpose, and will be improved by the following patch. load_program() is improved not to dump log buffer if it is empty. log buffer is also used to deduce whether the error was caused by an invalid program or other problem. v1 -> v2: - Using macro for error code. - Fetch error message based on array index, eliminate for-loop. - Use log buffer to detect the reason of failure. 3 new error code are introduced to replace LIBBPF_ERRNO__LOAD. In v1: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_big_program.o ls event syntax error: './test_big_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP In v2: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Kernel verifier blocks program loading SKIP # perf record -e ./test_kversion_nomatch_program.o event syntax error: './test_kversion_nomatch_program.o' \___ Incorrect kernel version SKIP (Will be further improved by following patches) # perf record -e ./test_big_program.o event syntax error: './test_big_program.o' \___ Program too big SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-06 13:49:37 +00:00
enum libbpf_errno {
__LIBBPF_ERRNO__START = 4000,
/* Something wrong in libelf */
LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */
LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */
LIBBPF_ERRNO__ENDIAN, /* Endian mismatch */
bpf tools: Improve libbpf error reporting In this patch, a series of libbpf specific error numbers and libbpf_strerror() are introduced to help reporting errors. Functions are updated to pass correct the error number through the CHECK_ERR() macro. All users of bpf_object__open{_buffer}() and bpf_program__title() in perf are modified accordingly. In addition, due to the error codes changing, bpf__strerror_load() is also modified to use them. bpf__strerror_head() is also changed accordingly so it can parse libbpf errors. bpf_loader_strerror() is introduced for that purpose, and will be improved by the following patch. load_program() is improved not to dump log buffer if it is empty. log buffer is also used to deduce whether the error was caused by an invalid program or other problem. v1 -> v2: - Using macro for error code. - Fetch error message based on array index, eliminate for-loop. - Use log buffer to detect the reason of failure. 3 new error code are introduced to replace LIBBPF_ERRNO__LOAD. In v1: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_big_program.o ls event syntax error: './test_big_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP In v2: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Kernel verifier blocks program loading SKIP # perf record -e ./test_kversion_nomatch_program.o event syntax error: './test_kversion_nomatch_program.o' \___ Incorrect kernel version SKIP (Will be further improved by following patches) # perf record -e ./test_big_program.o event syntax error: './test_big_program.o' \___ Program too big SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-06 13:49:37 +00:00
LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */
LIBBPF_ERRNO__RELOC, /* Relocation failed */
LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */
LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */
LIBBPF_ERRNO__PROG2BIG, /* Program too big */
LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
LIBBPF_ERRNO__PROGTYPE, /* Kernel doesn't support this program type */
LIBBPF_ERRNO__WRNGPID, /* Wrong pid in netlink message */
LIBBPF_ERRNO__INVSEQ, /* Invalid netlink sequence */
LIBBPF_ERRNO__NLPARSE, /* netlink parsing error */
bpf tools: Improve libbpf error reporting In this patch, a series of libbpf specific error numbers and libbpf_strerror() are introduced to help reporting errors. Functions are updated to pass correct the error number through the CHECK_ERR() macro. All users of bpf_object__open{_buffer}() and bpf_program__title() in perf are modified accordingly. In addition, due to the error codes changing, bpf__strerror_load() is also modified to use them. bpf__strerror_head() is also changed accordingly so it can parse libbpf errors. bpf_loader_strerror() is introduced for that purpose, and will be improved by the following patch. load_program() is improved not to dump log buffer if it is empty. log buffer is also used to deduce whether the error was caused by an invalid program or other problem. v1 -> v2: - Using macro for error code. - Fetch error message based on array index, eliminate for-loop. - Use log buffer to detect the reason of failure. 3 new error code are introduced to replace LIBBPF_ERRNO__LOAD. In v1: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_big_program.o ls event syntax error: './test_big_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP In v2: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Kernel verifier blocks program loading SKIP # perf record -e ./test_kversion_nomatch_program.o event syntax error: './test_kversion_nomatch_program.o' \___ Incorrect kernel version SKIP (Will be further improved by following patches) # perf record -e ./test_big_program.o event syntax error: './test_big_program.o' \___ Program too big SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-06 13:49:37 +00:00
__LIBBPF_ERRNO__END,
};
LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
enum libbpf_print_level {
LIBBPF_WARN,
LIBBPF_INFO,
LIBBPF_DEBUG,
};
typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level,
const char *, va_list ap);
LIBBPF_API libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn);
/* Hide internal to user */
struct bpf_object;
struct bpf_object_open_attr {
const char *file;
enum bpf_prog_type prog_type;
};
struct bpf_object_open_opts {
/* size of this struct, for forward/backward compatiblity */
size_t sz;
/* object name override, if provided:
* - for object open from file, this will override setting object
* name from file path's base name;
* - for object open from memory buffer, this will specify an object
* name and will override default "<addr>-<buf-size>" name;
*/
const char *object_name;
/* parse map definitions non-strictly, allowing extra attributes/data */
bool relaxed_maps;
/* DEPRECATED: handle CO-RE relocations non-strictly, allowing failures.
* Value is ignored. Relocations always are processed non-strictly.
* Non-relocatable instructions are replaced with invalid ones to
* prevent accidental errors.
* */
bool relaxed_core_relocs;
/* maps that set the 'pinning' attribute in their definition will have
* their pin_path attribute set to a file in this directory, and be
* auto-pinned to that path on load; defaults to "/sys/fs/bpf".
*/
const char *pin_root_path;
__u32 attach_prog_fd;
/* Additional kernel config content that augments and overrides
* system Kconfig for CONFIG_xxx externs.
libbpf: Support libbpf-provided extern variables Add support for extern variables, provided to BPF program by libbpf. Currently the following extern variables are supported: - LINUX_KERNEL_VERSION; version of a kernel in which BPF program is executing, follows KERNEL_VERSION() macro convention, can be 4- and 8-byte long; - CONFIG_xxx values; a set of values of actual kernel config. Tristate, boolean, strings, and integer values are supported. Set of possible values is determined by declared type of extern variable. Supported types of variables are: - Tristate values. Are represented as `enum libbpf_tristate`. Accepted values are **strictly** 'y', 'n', or 'm', which are represented as TRI_YES, TRI_NO, or TRI_MODULE, respectively. - Boolean values. Are represented as bool (_Bool) types. Accepted values are 'y' and 'n' only, turning into true/false values, respectively. - Single-character values. Can be used both as a substritute for bool/tristate, or as a small-range integer: - 'y'/'n'/'m' are represented as is, as characters 'y', 'n', or 'm'; - integers in a range [-128, 127] or [0, 255] (depending on signedness of char in target architecture) are recognized and represented with respective values of char type. - Strings. String values are declared as fixed-length char arrays. String of up to that length will be accepted and put in first N bytes of char array, with the rest of bytes zeroed out. If config string value is longer than space alloted, it will be truncated and warning message emitted. Char array is always zero terminated. String literals in config have to be enclosed in double quotes, just like C-style string literals. - Integers. 8-, 16-, 32-, and 64-bit integers are supported, both signed and unsigned variants. Libbpf enforces parsed config value to be in the supported range of corresponding integer type. Integers values in config can be: - decimal integers, with optional + and - signs; - hexadecimal integers, prefixed with 0x or 0X; - octal integers, starting with 0. Config file itself is searched in /boot/config-$(uname -r) location with fallback to /proc/config.gz, unless config path is specified explicitly through bpf_object_open_opts' kernel_config_path option. Both gzipped and plain text formats are supported. Libbpf adds explicit dependency on zlib because of this, but this shouldn't be a problem, given libelf already depends on zlib. All detected extern variables, are put into a separate .extern internal map. It, similarly to .rodata map, is marked as read-only from BPF program side, as well as is frozen on load. This allows BPF verifier to track extern values as constants and perform enhanced branch prediction and dead code elimination. This can be relied upon for doing kernel version/feature detection and using potentially unsupported field relocations or BPF helpers in a CO-RE-based BPF program, while still having a single version of BPF program running on old and new kernels. Selftests are validating this explicitly for unexisting BPF helper. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014710.3449601-3-andriin@fb.com
2019-12-14 01:47:08 +00:00
*/
const char *kconfig;
};
#define bpf_object_open_opts__last_field kconfig
LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
LIBBPF_API struct bpf_object *
bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts);
LIBBPF_API struct bpf_object *
bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
const struct bpf_object_open_opts *opts);
/* deprecated bpf_object__open variants */
LIBBPF_API struct bpf_object *
bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
const char *name);
LIBBPF_API struct bpf_object *
bpf_object__open_xattr(struct bpf_object_open_attr *attr);
enum libbpf_pin_type {
LIBBPF_PIN_NONE,
/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
LIBBPF_PIN_BY_NAME,
};
/* pin_maps and unpin_maps can both be called with a NULL path, in which case
* they will use the pin_path attribute of each map (and ignore all maps that
* don't have a pin_path set).
*/
LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
LIBBPF_API void bpf_object__close(struct bpf_object *object);
struct bpf_object_load_attr {
struct bpf_object *obj;
int log_level;
const char *target_btf_path;
};
/* Load/unload object into/from kernel */
LIBBPF_API int bpf_object__load(struct bpf_object *obj);
LIBBPF_API int bpf_object__load_xattr(struct bpf_object_load_attr *attr);
LIBBPF_API int bpf_object__unload(struct bpf_object *obj);
LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
struct btf;
LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
LIBBPF_API struct bpf_program *
bpf_object__find_program_by_title(const struct bpf_object *obj,
const char *title);
LIBBPF_API struct bpf_program *
bpf_object__find_program_by_name(const struct bpf_object *obj,
const char *name);
LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);
#define bpf_object__for_each_safe(pos, tmp) \
for ((pos) = bpf_object__next(NULL), \
(tmp) = bpf_object__next(pos); \
(pos) != NULL; \
(pos) = (tmp), (tmp) = bpf_object__next(tmp))
typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *);
LIBBPF_API int bpf_object__set_priv(struct bpf_object *obj, void *priv,
bpf_object_clear_priv_t clear_priv);
LIBBPF_API void *bpf_object__priv(const struct bpf_object *prog);
LIBBPF_API int
libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type);
LIBBPF_API int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type);
LIBBPF_API int libbpf_find_vmlinux_btf_id(const char *name,
enum bpf_attach_type attach_type);
/* Accessors of bpf_program */
struct bpf_program;
LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog,
const struct bpf_object *obj);
#define bpf_object__for_each_program(pos, obj) \
for ((pos) = bpf_program__next(NULL, (obj)); \
(pos) != NULL; \
(pos) = bpf_program__next((pos), (obj)))
LIBBPF_API struct bpf_program *bpf_program__prev(struct bpf_program *prog,
const struct bpf_object *obj);
typedef void (*bpf_program_clear_priv_t)(struct bpf_program *, void *);
LIBBPF_API int bpf_program__set_priv(struct bpf_program *prog, void *priv,
bpf_program_clear_priv_t clear_priv);
LIBBPF_API void *bpf_program__priv(const struct bpf_program *prog);
LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
__u32 ifindex);
LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog);
LIBBPF_API const char *bpf_program__title(const struct bpf_program *prog,
bool needs_copy);
/* returns program size in bytes */
LIBBPF_API size_t bpf_program__size(const struct bpf_program *prog);
LIBBPF_API int bpf_program__load(struct bpf_program *prog, char *license,
__u32 kern_version);
LIBBPF_API int bpf_program__fd(const struct bpf_program *prog);
LIBBPF_API int bpf_program__pin_instance(struct bpf_program *prog,
const char *path,
int instance);
LIBBPF_API int bpf_program__unpin_instance(struct bpf_program *prog,
const char *path,
int instance);
LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path);
LIBBPF_API int bpf_program__unpin(struct bpf_program *prog, const char *path);
LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
struct bpf_link;
LIBBPF_API struct bpf_link *bpf_link__open(const char *path);
LIBBPF_API int bpf_link__fd(const struct bpf_link *link);
LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link);
LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path);
LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
LIBBPF_API int bpf_link__update_program(struct bpf_link *link,
struct bpf_program *prog);
libbpf: Add bpf_link__disconnect() API to preserve underlying BPF resource There are cases in which BPF resource (program, map, etc) has to outlive userspace program that "installed" it in the system in the first place. When BPF program is attached, libbpf returns bpf_link object, which is supposed to be destroyed after no longer necessary through bpf_link__destroy() API. Currently, bpf_link destruction causes both automatic detachment and frees up any resources allocated to for bpf_link in-memory representation. This is inconvenient for the case described above because of coupling of detachment and resource freeing. This patch introduces bpf_link__disconnect() API call, which marks bpf_link as disconnected from its underlying BPF resouces. This means that when bpf_link is destroyed later, all its memory resources will be freed, but BPF resource itself won't be detached. This design allows to follow strict and resource-leak-free design by default, while giving easy and straightforward way for user code to opt for keeping BPF resource attached beyond lifetime of a bpf_link. For some BPF programs (i.e., FS-based tracepoints, kprobes, raw tracepoint, etc), user has to make sure to pin BPF program to prevent kernel to automatically detach it on process exit. This should typically be achived by pinning BPF program (or map in some cases) in BPF FS. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20191218225039.2668205-1-andriin@fb.com
2019-12-18 22:50:39 +00:00
LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
LIBBPF_API struct bpf_link *
bpf_program__attach(struct bpf_program *prog);
LIBBPF_API struct bpf_link *
bpf_program__attach_perf_event(struct bpf_program *prog, int pfd);
LIBBPF_API struct bpf_link *
bpf_program__attach_kprobe(struct bpf_program *prog, bool retprobe,
const char *func_name);
LIBBPF_API struct bpf_link *
bpf_program__attach_uprobe(struct bpf_program *prog, bool retprobe,
pid_t pid, const char *binary_path,
size_t func_offset);
LIBBPF_API struct bpf_link *
bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name);
LIBBPF_API struct bpf_link *
bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name);
LIBBPF_API struct bpf_link *
bpf_program__attach_trace(struct bpf_program *prog);
LIBBPF_API struct bpf_link *
bpf_program__attach_lsm(struct bpf_program *prog);
LIBBPF_API struct bpf_link *
bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd);
LIBBPF_API struct bpf_link *
bpf_program__attach_netns(struct bpf_program *prog, int netns_fd);
bpf: libbpf: Add STRUCT_OPS support This patch adds BPF STRUCT_OPS support to libbpf. The only sec_name convention is SEC(".struct_ops") to identify the struct_ops implemented in BPF, e.g. To implement a tcp_congestion_ops: SEC(".struct_ops") struct tcp_congestion_ops dctcp = { .init = (void *)dctcp_init, /* <-- a bpf_prog */ /* ... some more func prts ... */ .name = "bpf_dctcp", }; Each struct_ops is defined as a global variable under SEC(".struct_ops") as above. libbpf creates a map for each variable and the variable name is the map's name. Multiple struct_ops is supported under SEC(".struct_ops"). In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops") section and find out what is the btf-type the struct_ops is implementing. Note that the btf-type here is referring to a type in the bpf_prog.o's btf. A "struct bpf_map" is added by bpf_object__add_map() as other maps do. It will then collect (through SHT_REL) where are the bpf progs that the func ptrs are referring to. No btf_vmlinux is needed in the open phase. In the bpf_object__load phase, the map-fields, which depend on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()). It will also set the prog->type, prog->attach_btf_id, and prog->expected_attach_type. Thus, the prog's properties do not rely on its section name. [ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching process is as simple as: member-name match + btf-kind match + size match. If these matching conditions fail, libbpf will reject. The current targeting support is "struct tcp_congestion_ops" which most of its members are function pointers. The member ordering of the bpf_prog's btf-type can be different from the btf_vmlinux's btf-type. ] Then, all obj->maps are created as usual (in bpf_object__create_maps()). Once the maps are created and prog's properties are all set, the libbpf will proceed to load all the progs. bpf_map__attach_struct_ops() is added to register a struct_ops map to a kernel subsystem. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200109003514.3856730-1-kafai@fb.com
2020-01-09 00:35:14 +00:00
struct bpf_map;
bpf: libbpf: Add STRUCT_OPS support This patch adds BPF STRUCT_OPS support to libbpf. The only sec_name convention is SEC(".struct_ops") to identify the struct_ops implemented in BPF, e.g. To implement a tcp_congestion_ops: SEC(".struct_ops") struct tcp_congestion_ops dctcp = { .init = (void *)dctcp_init, /* <-- a bpf_prog */ /* ... some more func prts ... */ .name = "bpf_dctcp", }; Each struct_ops is defined as a global variable under SEC(".struct_ops") as above. libbpf creates a map for each variable and the variable name is the map's name. Multiple struct_ops is supported under SEC(".struct_ops"). In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops") section and find out what is the btf-type the struct_ops is implementing. Note that the btf-type here is referring to a type in the bpf_prog.o's btf. A "struct bpf_map" is added by bpf_object__add_map() as other maps do. It will then collect (through SHT_REL) where are the bpf progs that the func ptrs are referring to. No btf_vmlinux is needed in the open phase. In the bpf_object__load phase, the map-fields, which depend on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()). It will also set the prog->type, prog->attach_btf_id, and prog->expected_attach_type. Thus, the prog's properties do not rely on its section name. [ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching process is as simple as: member-name match + btf-kind match + size match. If these matching conditions fail, libbpf will reject. The current targeting support is "struct tcp_congestion_ops" which most of its members are function pointers. The member ordering of the bpf_prog's btf-type can be different from the btf_vmlinux's btf-type. ] Then, all obj->maps are created as usual (in bpf_object__create_maps()). Once the maps are created and prog's properties are all set, the libbpf will proceed to load all the progs. bpf_map__attach_struct_ops() is added to register a struct_ops map to a kernel subsystem. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200109003514.3856730-1-kafai@fb.com
2020-01-09 00:35:14 +00:00
LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map);
struct bpf_iter_attach_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
};
#define bpf_iter_attach_opts__last_field sz
LIBBPF_API struct bpf_link *
bpf_program__attach_iter(struct bpf_program *prog,
const struct bpf_iter_attach_opts *opts);
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
struct bpf_insn;
/*
* Libbpf allows callers to adjust BPF programs before being loaded
* into kernel. One program in an object file can be transformed into
* multiple variants to be attached to different hooks.
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
*
* bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
* form an API for this purpose.
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
*
* - bpf_program_prep_t:
* Defines a 'preprocessor', which is a caller defined function
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
* passed to libbpf through bpf_program__set_prep(), and will be
* called before program is loaded. The processor should adjust
* the program one time for each instance according to the instance id
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
* passed to it.
*
* - bpf_program__set_prep:
* Attaches a preprocessor to a BPF program. The number of instances
* that should be created is also passed through this function.
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
*
* - bpf_program__nth_fd:
* After the program is loaded, get resulting FD of a given instance
* of the BPF program.
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
*
* If bpf_program__set_prep() is not used, the program would be loaded
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
* without adjustment during bpf_object__load(). The program has only
* one instance. In this case bpf_program__fd(prog) is equal to
* bpf_program__nth_fd(prog, 0).
*/
struct bpf_prog_prep_result {
/*
* If not NULL, load new instruction array.
* If set to NULL, don't load this instance.
*/
struct bpf_insn *new_insn_ptr;
int new_insn_cnt;
/* If not NULL, result FD is written to it. */
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
int *pfd;
};
/*
* Parameters of bpf_program_prep_t:
* - prog: The bpf_program being loaded.
* - n: Index of instance being generated.
* - insns: BPF instructions array.
* - insns_cnt:Number of instructions in insns.
* - res: Output parameter, result of transformation.
*
* Return value:
* - Zero: pre-processing success.
* - Non-zero: pre-processing error, stop loading.
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
*/
typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
struct bpf_insn *insns, int insns_cnt,
struct bpf_prog_prep_result *res);
LIBBPF_API int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
bpf_program_prep_t prep);
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
LIBBPF_API int bpf_program__nth_fd(const struct bpf_program *prog, int n);
bpf tools: Load a program with different instances using preprocessor This patch is a preparation for BPF prologue support which allows generating a series of BPF bytecode for fetching kernel data before calling program code. With the newly introduced multiple instances support, perf is able to create different prologues for different kprobe points. Before this patch, a bpf_program can be loaded into kernel only once, and get the only resulting fd. What this patch does is to allow creating and loading different variants of one bpf_program, then fetching their fds. Here we describe the basic idea in this patch. The detailed description of the newly introduced APIs can be found in comments in the patch body. The key of this patch is the new mechanism in bpf_program__load(). Instead of loading BPF program into kernel directly, it calls a 'pre-processor' to generate program instances which would be finally loaded into the kernel based on the original code. To enable the generation of multiple instances, libbpf passes an index to the pre-processor so it know which instance is being loaded. Pre-processor should be called from libbpf's user (perf) using bpf_program__set_prep(). The number of instances and the relationship between indices and the target instance should be clear when calling bpf_program__set_prep(). To retrieve a fd for a specific instance of a program, bpf_program__nth_fd() is introduced. It returns the resulting fd according to index. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> [ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-16 12:10:09 +00:00
/*
* Adjust type of BPF program. Default is kprobe.
*/
LIBBPF_API int bpf_program__set_socket_filter(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_tracepoint(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_raw_tracepoint(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_kprobe(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_lsm(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_tracing(struct bpf_program *prog);
bpf: libbpf: Add STRUCT_OPS support This patch adds BPF STRUCT_OPS support to libbpf. The only sec_name convention is SEC(".struct_ops") to identify the struct_ops implemented in BPF, e.g. To implement a tcp_congestion_ops: SEC(".struct_ops") struct tcp_congestion_ops dctcp = { .init = (void *)dctcp_init, /* <-- a bpf_prog */ /* ... some more func prts ... */ .name = "bpf_dctcp", }; Each struct_ops is defined as a global variable under SEC(".struct_ops") as above. libbpf creates a map for each variable and the variable name is the map's name. Multiple struct_ops is supported under SEC(".struct_ops"). In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops") section and find out what is the btf-type the struct_ops is implementing. Note that the btf-type here is referring to a type in the bpf_prog.o's btf. A "struct bpf_map" is added by bpf_object__add_map() as other maps do. It will then collect (through SHT_REL) where are the bpf progs that the func ptrs are referring to. No btf_vmlinux is needed in the open phase. In the bpf_object__load phase, the map-fields, which depend on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()). It will also set the prog->type, prog->attach_btf_id, and prog->expected_attach_type. Thus, the prog's properties do not rely on its section name. [ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching process is as simple as: member-name match + btf-kind match + size match. If these matching conditions fail, libbpf will reject. The current targeting support is "struct tcp_congestion_ops" which most of its members are function pointers. The member ordering of the bpf_prog's btf-type can be different from the btf_vmlinux's btf-type. ] Then, all obj->maps are created as usual (in bpf_object__create_maps()). Once the maps are created and prog's properties are all set, the libbpf will proceed to load all the progs. bpf_map__attach_struct_ops() is added to register a struct_ops map to a kernel subsystem. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200109003514.3856730-1-kafai@fb.com
2020-01-09 00:35:14 +00:00
LIBBPF_API int bpf_program__set_struct_ops(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_extension(struct bpf_program *prog);
LIBBPF_API enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog);
LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
enum bpf_prog_type type);
LIBBPF_API enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog);
LIBBPF_API void
bpf_program__set_expected_attach_type(struct bpf_program *prog,
enum bpf_attach_type type);
LIBBPF_API int
bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
const char *attach_func_name);
LIBBPF_API bool bpf_program__is_socket_filter(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_tracepoint(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_raw_tracepoint(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_kprobe(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_lsm(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_perf_event(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_tracing(const struct bpf_program *prog);
bpf: libbpf: Add STRUCT_OPS support This patch adds BPF STRUCT_OPS support to libbpf. The only sec_name convention is SEC(".struct_ops") to identify the struct_ops implemented in BPF, e.g. To implement a tcp_congestion_ops: SEC(".struct_ops") struct tcp_congestion_ops dctcp = { .init = (void *)dctcp_init, /* <-- a bpf_prog */ /* ... some more func prts ... */ .name = "bpf_dctcp", }; Each struct_ops is defined as a global variable under SEC(".struct_ops") as above. libbpf creates a map for each variable and the variable name is the map's name. Multiple struct_ops is supported under SEC(".struct_ops"). In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops") section and find out what is the btf-type the struct_ops is implementing. Note that the btf-type here is referring to a type in the bpf_prog.o's btf. A "struct bpf_map" is added by bpf_object__add_map() as other maps do. It will then collect (through SHT_REL) where are the bpf progs that the func ptrs are referring to. No btf_vmlinux is needed in the open phase. In the bpf_object__load phase, the map-fields, which depend on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()). It will also set the prog->type, prog->attach_btf_id, and prog->expected_attach_type. Thus, the prog's properties do not rely on its section name. [ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching process is as simple as: member-name match + btf-kind match + size match. If these matching conditions fail, libbpf will reject. The current targeting support is "struct tcp_congestion_ops" which most of its members are function pointers. The member ordering of the bpf_prog's btf-type can be different from the btf_vmlinux's btf-type. ] Then, all obj->maps are created as usual (in bpf_object__create_maps()). Once the maps are created and prog's properties are all set, the libbpf will proceed to load all the progs. bpf_map__attach_struct_ops() is added to register a struct_ops map to a kernel subsystem. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200109003514.3856730-1-kafai@fb.com
2020-01-09 00:35:14 +00:00
LIBBPF_API bool bpf_program__is_struct_ops(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_extension(const struct bpf_program *prog);
bpf tools: Record map accessing instructions for each program This patch records the indices of instructions which are needed to be relocated. That information is saved in the 'reloc_desc' field in 'struct bpf_program'. In the loading phase (this patch takes effect in the opening phase), the collected instructions will be replaced by map loading instructions. Since we are going to close the ELF file and clear all data at the end of the 'opening' phase, the ELF information will no longer be valid in the 'loading' phase. We have to locate the instructions before maps are loaded, instead of directly modifying the instruction. 'struct bpf_map_def' is introduced in this patch to let us know how many maps are defined in the object. This is the third part of map relocation. The principle of map relocation is described in commit message of 'bpf tools: Collect symbol table from SHT_SYMTAB section'. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-15-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-07-01 02:14:02 +00:00
/*
* No need for __attribute__((packed)), all members of 'bpf_map_def'
* are all aligned. In addition, using __attribute__((packed))
* would trigger a -Wpacked warning message, and lead to an error
* if -Werror is set.
bpf tools: Record map accessing instructions for each program This patch records the indices of instructions which are needed to be relocated. That information is saved in the 'reloc_desc' field in 'struct bpf_program'. In the loading phase (this patch takes effect in the opening phase), the collected instructions will be replaced by map loading instructions. Since we are going to close the ELF file and clear all data at the end of the 'opening' phase, the ELF information will no longer be valid in the 'loading' phase. We have to locate the instructions before maps are loaded, instead of directly modifying the instruction. 'struct bpf_map_def' is introduced in this patch to let us know how many maps are defined in the object. This is the third part of map relocation. The principle of map relocation is described in commit message of 'bpf tools: Collect symbol table from SHT_SYMTAB section'. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-15-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-07-01 02:14:02 +00:00
*/
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
unsigned int map_flags;
bpf tools: Record map accessing instructions for each program This patch records the indices of instructions which are needed to be relocated. That information is saved in the 'reloc_desc' field in 'struct bpf_program'. In the loading phase (this patch takes effect in the opening phase), the collected instructions will be replaced by map loading instructions. Since we are going to close the ELF file and clear all data at the end of the 'opening' phase, the ELF information will no longer be valid in the 'loading' phase. We have to locate the instructions before maps are loaded, instead of directly modifying the instruction. 'struct bpf_map_def' is introduced in this patch to let us know how many maps are defined in the object. This is the third part of map relocation. The principle of map relocation is described in commit message of 'bpf tools: Collect symbol table from SHT_SYMTAB section'. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-15-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-07-01 02:14:02 +00:00
};
/*
* The 'struct bpf_map' in include/linux/bpf.h is internal to the kernel,
* so no need to worry about a name clash.
*/
LIBBPF_API struct bpf_map *
bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name);
LIBBPF_API int
bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name);
/*
* Get bpf_map through the offset of corresponding struct bpf_map_def
* in the BPF object file.
*/
LIBBPF_API struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);
LIBBPF_API struct bpf_map *
bpf_map__next(const struct bpf_map *map, const struct bpf_object *obj);
#define bpf_object__for_each_map(pos, obj) \
for ((pos) = bpf_map__next(NULL, (obj)); \
(pos) != NULL; \
(pos) = bpf_map__next((pos), (obj)))
#define bpf_map__for_each bpf_object__for_each_map
LIBBPF_API struct bpf_map *
bpf_map__prev(const struct bpf_map *map, const struct bpf_object *obj);
LIBBPF_API int bpf_map__fd(const struct bpf_map *map);
LIBBPF_API const struct bpf_map_def *bpf_map__def(const struct bpf_map *map);
LIBBPF_API const char *bpf_map__name(const struct bpf_map *map);
LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv,
bpf_map_clear_priv_t clear_priv);
LIBBPF_API void *bpf_map__priv(const struct bpf_map *map);
LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
const void *data, size_t size);
LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
LIBBPF_API int bpf_map__resize(struct bpf_map *map, __u32 max_entries);
LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map);
LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
LIBBPF_API const char *bpf_map__get_pin_path(const struct bpf_map *map);
LIBBPF_API bool bpf_map__is_pinned(const struct bpf_map *map);
LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
LIBBPF_API long libbpf_get_error(const void *ptr);
struct bpf_prog_load_attr {
const char *file;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
int ifindex;
int log_level;
int prog_flags;
};
LIBBPF_API int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_object **pobj, int *prog_fd);
LIBBPF_API int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd);
struct xdp_link_info {
__u32 prog_id;
__u32 drv_prog_id;
__u32 hw_prog_id;
__u32 skb_prog_id;
__u8 attach_mode;
};
struct bpf_xdp_set_link_opts {
size_t sz;
int old_fd;
};
#define bpf_xdp_set_link_opts__last_field old_fd
LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
LIBBPF_API int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
const struct bpf_xdp_set_link_opts *opts);
LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags);
LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
size_t info_size, __u32 flags);
libbpf: Add BPF ring buffer support Declaring and instantiating BPF ring buffer doesn't require any changes to libbpf, as it's just another type of maps. So using existing BTF-defined maps syntax with __uint(type, BPF_MAP_TYPE_RINGBUF) and __uint(max_elements, <size-of-ring-buf>) is all that's necessary to create and use BPF ring buffer. This patch adds BPF ring buffer consumer to libbpf. It is very similar to perf_buffer implementation in terms of API, but also attempts to fix some minor problems and inconveniences with existing perf_buffer API. ring_buffer support both single ring buffer use case (with just using ring_buffer__new()), as well as allows to add more ring buffers, each with its own callback and context. This allows to efficiently poll and consume multiple, potentially completely independent, ring buffers, using single epoll instance. The latter is actually a problem in practice for applications that are using multiple sets of perf buffers. They have to create multiple instances for struct perf_buffer and poll them independently or in a loop, each approach having its own problems (e.g., inability to use a common poll timeout). struct ring_buffer eliminates this problem by aggregating many independent ring buffer instances under the single "ring buffer manager". Second, perf_buffer's callback can't return error, so applications that need to stop polling due to error in data or data signalling the end, have to use extra mechanisms to signal that polling has to stop. ring_buffer's callback can return error, which will be passed through back to user code and can be acted upon appropariately. Two APIs allow to consume ring buffer data: - ring_buffer__poll(), which will wait for data availability notification and will consume data only from reported ring buffer(s); this API allows to efficiently use resources by reading data only when it becomes available; - ring_buffer__consume(), will attempt to read new records regardless of data availablity notification sub-system. This API is useful for cases when lowest latency is required, in expense of burning CPU resources. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200529075424.3139988-3-andriin@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-05-29 07:54:21 +00:00
/* Ring buffer APIs */
struct ring_buffer;
typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
struct ring_buffer_opts {
size_t sz; /* size of this struct, for forward/backward compatiblity */
};
#define ring_buffer_opts__last_field sz
LIBBPF_API struct ring_buffer *
ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
const struct ring_buffer_opts *opts);
LIBBPF_API void ring_buffer__free(struct ring_buffer *rb);
LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
ring_buffer_sample_fn sample_cb, void *ctx);
LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
/* Perf buffer APIs */
libbpf: add perf buffer API BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program to user space for additional processing. libbpf already has very low-level API to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to use and requires a lot of code to set everything up. This patch adds perf_buffer abstraction on top of it, abstracting setting up and polling per-CPU logic into simple and convenient API, similar to what BCC provides. perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF map entries. It accepts two user-provided callbacks: one for handling raw samples and one for get notifications of lost samples due to buffer overflow. perf_buffer__new_raw() is similar, but provides more control over how perf events are set up (by accepting user-provided perf_event_attr), how they are handled (perf_event_header pointer is passed directly to user-provided callback), and on which CPUs ring buffers are created (it's possible to provide a list of CPUs and corresponding map keys to update). This API allows advanced users fuller control. perf_buffer__poll() is used to fetch ring buffer data across all CPUs, utilizing epoll instance. perf_buffer__free() does corresponding clean up and unsets FDs from BPF map. All APIs are not thread-safe. User should ensure proper locking/coordination if used in multi-threaded set up. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-06 18:06:24 +00:00
struct perf_buffer;
typedef void (*perf_buffer_sample_fn)(void *ctx, int cpu,
void *data, __u32 size);
typedef void (*perf_buffer_lost_fn)(void *ctx, int cpu, __u64 cnt);
/* common use perf buffer options */
struct perf_buffer_opts {
/* if specified, sample_cb is called for each sample */
perf_buffer_sample_fn sample_cb;
/* if specified, lost_cb is called for each batch of lost samples */
perf_buffer_lost_fn lost_cb;
/* ctx is provided to sample_cb and lost_cb */
void *ctx;
};
LIBBPF_API struct perf_buffer *
perf_buffer__new(int map_fd, size_t page_cnt,
const struct perf_buffer_opts *opts);
enum bpf_perf_event_ret {
LIBBPF_PERF_EVENT_DONE = 0,
LIBBPF_PERF_EVENT_ERROR = -1,
LIBBPF_PERF_EVENT_CONT = -2,
};
struct perf_event_header;
libbpf: add perf buffer API BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program to user space for additional processing. libbpf already has very low-level API to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to use and requires a lot of code to set everything up. This patch adds perf_buffer abstraction on top of it, abstracting setting up and polling per-CPU logic into simple and convenient API, similar to what BCC provides. perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF map entries. It accepts two user-provided callbacks: one for handling raw samples and one for get notifications of lost samples due to buffer overflow. perf_buffer__new_raw() is similar, but provides more control over how perf events are set up (by accepting user-provided perf_event_attr), how they are handled (perf_event_header pointer is passed directly to user-provided callback), and on which CPUs ring buffers are created (it's possible to provide a list of CPUs and corresponding map keys to update). This API allows advanced users fuller control. perf_buffer__poll() is used to fetch ring buffer data across all CPUs, utilizing epoll instance. perf_buffer__free() does corresponding clean up and unsets FDs from BPF map. All APIs are not thread-safe. User should ensure proper locking/coordination if used in multi-threaded set up. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-06 18:06:24 +00:00
typedef enum bpf_perf_event_ret
(*perf_buffer_event_fn)(void *ctx, int cpu, struct perf_event_header *event);
/* raw perf buffer options, giving most power and control */
struct perf_buffer_raw_opts {
/* perf event attrs passed directly into perf_event_open() */
struct perf_event_attr *attr;
/* raw event callback */
perf_buffer_event_fn event_cb;
/* ctx is provided to event_cb */
void *ctx;
/* if cpu_cnt == 0, open all on all possible CPUs (up to the number of
* max_entries of given PERF_EVENT_ARRAY map)
*/
int cpu_cnt;
/* if cpu_cnt > 0, cpus is an array of CPUs to open ring buffers on */
int *cpus;
/* if cpu_cnt > 0, map_keys specify map keys to set per-CPU FDs for */
int *map_keys;
};
LIBBPF_API struct perf_buffer *
perf_buffer__new_raw(int map_fd, size_t page_cnt,
const struct perf_buffer_raw_opts *opts);
LIBBPF_API void perf_buffer__free(struct perf_buffer *pb);
LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms);
LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
libbpf: add perf buffer API BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program to user space for additional processing. libbpf already has very low-level API to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to use and requires a lot of code to set everything up. This patch adds perf_buffer abstraction on top of it, abstracting setting up and polling per-CPU logic into simple and convenient API, similar to what BCC provides. perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF map entries. It accepts two user-provided callbacks: one for handling raw samples and one for get notifications of lost samples due to buffer overflow. perf_buffer__new_raw() is similar, but provides more control over how perf events are set up (by accepting user-provided perf_event_attr), how they are handled (perf_event_header pointer is passed directly to user-provided callback), and on which CPUs ring buffers are created (it's possible to provide a list of CPUs and corresponding map keys to update). This API allows advanced users fuller control. perf_buffer__poll() is used to fetch ring buffer data across all CPUs, utilizing epoll instance. perf_buffer__free() does corresponding clean up and unsets FDs from BPF map. All APIs are not thread-safe. User should ensure proper locking/coordination if used in multi-threaded set up. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-06 18:06:24 +00:00
typedef enum bpf_perf_event_ret
(*bpf_perf_event_print_t)(struct perf_event_header *hdr,
void *private_data);
LIBBPF_API 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);
bpf: libbpf: bpftool: Print bpf_line_info during prog dump This patch adds print bpf_line_info function in 'prog dump jitted' and 'prog dump xlated': [root@arch-fb-vm1 bpf]# ~/devshare/fb-kernel/linux/tools/bpf/bpftool/bpftool prog dump jited pinned /sys/fs/bpf/test_btf_haskv [...] int test_long_fname_2(struct dummy_tracepoint_args * arg): bpf_prog_44a040bf25481309_test_long_fname_2: ; static int test_long_fname_2(struct dummy_tracepoint_args *arg) 0: push %rbp 1: mov %rsp,%rbp 4: sub $0x30,%rsp b: sub $0x28,%rbp f: mov %rbx,0x0(%rbp) 13: mov %r13,0x8(%rbp) 17: mov %r14,0x10(%rbp) 1b: mov %r15,0x18(%rbp) 1f: xor %eax,%eax 21: mov %rax,0x20(%rbp) 25: xor %esi,%esi ; int key = 0; 27: mov %esi,-0x4(%rbp) ; if (!arg->sock) 2a: mov 0x8(%rdi),%rdi ; if (!arg->sock) 2e: cmp $0x0,%rdi 32: je 0x0000000000000070 34: mov %rbp,%rsi ; counts = bpf_map_lookup_elem(&btf_map, &key); 37: add $0xfffffffffffffffc,%rsi 3b: movabs $0xffff8881139d7480,%rdi 45: add $0x110,%rdi 4c: mov 0x0(%rsi),%eax 4f: cmp $0x4,%rax 53: jae 0x000000000000005e 55: shl $0x3,%rax 59: add %rdi,%rax 5c: jmp 0x0000000000000060 5e: xor %eax,%eax ; if (!counts) 60: cmp $0x0,%rax 64: je 0x0000000000000070 ; counts->v6++; 66: mov 0x4(%rax),%edi 69: add $0x1,%rdi 6d: mov %edi,0x4(%rax) 70: mov 0x0(%rbp),%rbx 74: mov 0x8(%rbp),%r13 78: mov 0x10(%rbp),%r14 7c: mov 0x18(%rbp),%r15 80: add $0x28,%rbp 84: leaveq 85: retq [...] With linum: [root@arch-fb-vm1 bpf]# ~/devshare/fb-kernel/linux/tools/bpf/bpftool/bpftool prog dump jited pinned /sys/fs/bpf/test_btf_haskv linum int _dummy_tracepoint(struct dummy_tracepoint_args * arg): bpf_prog_b07ccb89267cf242__dummy_tracepoint: ; return test_long_fname_1(arg); [file:/data/users/kafai/fb-kernel/linux/tools/testing/selftests/bpf/test_btf_haskv.c line_num:54 line_col:9] 0: push %rbp 1: mov %rsp,%rbp 4: sub $0x28,%rsp b: sub $0x28,%rbp f: mov %rbx,0x0(%rbp) 13: mov %r13,0x8(%rbp) 17: mov %r14,0x10(%rbp) 1b: mov %r15,0x18(%rbp) 1f: xor %eax,%eax 21: mov %rax,0x20(%rbp) 25: callq 0x000000000000851e ; return test_long_fname_1(arg); [file:/data/users/kafai/fb-kernel/linux/tools/testing/selftests/bpf/test_btf_haskv.c line_num:54 line_col:2] 2a: xor %eax,%eax 2c: mov 0x0(%rbp),%rbx 30: mov 0x8(%rbp),%r13 34: mov 0x10(%rbp),%r14 38: mov 0x18(%rbp),%r15 3c: add $0x28,%rbp 40: leaveq 41: retq [...] Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-08 00:42:32 +00:00
struct bpf_prog_linfo;
struct bpf_prog_info;
LIBBPF_API void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo);
LIBBPF_API struct bpf_prog_linfo *
bpf_prog_linfo__new(const struct bpf_prog_info *info);
LIBBPF_API const struct bpf_line_info *
bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo,
__u64 addr, __u32 func_idx, __u32 nr_skip);
LIBBPF_API const struct bpf_line_info *
bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
__u32 insn_off, __u32 nr_skip);
tools: bpftool: add probes for eBPF program types Introduce probes for supported BPF program types in libbpf, and call it from bpftool to test what types are available on the system. The probe simply consists in loading a very basic program of that type and see if the verifier complains or not. Sample output: # bpftool feature probe kernel ... Scanning eBPF program types... eBPF program_type socket_filter is available eBPF program_type kprobe is available eBPF program_type sched_cls is available ... # bpftool --json --pretty feature probe kernel { ... "program_types": { "have_socket_filter_prog_type": true, "have_kprobe_prog_type": true, "have_sched_cls_prog_type": true, ... } } v5: - In libbpf.map, move global symbol to a new LIBBPF_0.0.2 section. - Rename (non-API function) prog_load() as probe_load(). v3: - Get kernel version for checking kprobes availability from libbpf instead of from bpftool. Do not pass kernel_version as an argument when calling libbpf probes. - Use a switch with all enum values for setting specific program parameters just before probing, so that gcc complains at compile time (-Wswitch-enum) if new prog types were added to the kernel but libbpf was not updated. - Add a comment in libbpf.h about setrlimit() usage to allow many consecutive probe attempts. v2: - Move probes from bpftool to libbpf. - Remove C-style macros output from this patch. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:53 +00:00
/*
* Probe for supported system features
*
* Note that running many of these probes in a short amount of time can cause
* the kernel to reach the maximal size of lockable memory allowed for the
* user, causing subsequent probes to fail. In this case, the caller may want
* to adjust that limit with setrlimit().
*/
LIBBPF_API bool bpf_probe_prog_type(enum bpf_prog_type prog_type,
__u32 ifindex);
LIBBPF_API bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex);
tools: bpftool: add probes for eBPF helper functions Similarly to what was done for program types and map types, add a set of probes to test the availability of the different eBPF helper functions on the current system. For each known program type, all known helpers are tested, in order to establish a compatibility matrix. Output is provided as a set of lists of available helpers, one per program type. Sample output: # bpftool feature probe kernel ... Scanning eBPF helper functions... eBPF helpers supported for program type socket_filter: - bpf_map_lookup_elem - bpf_map_update_elem - bpf_map_delete_elem ... eBPF helpers supported for program type kprobe: - bpf_map_lookup_elem - bpf_map_update_elem - bpf_map_delete_elem ... # bpftool --json --pretty feature probe kernel { ... "helpers": { "socket_filter_available_helpers": ["bpf_map_lookup_elem", \ "bpf_map_update_elem","bpf_map_delete_elem", ... ], "kprobe_available_helpers": ["bpf_map_lookup_elem", \ "bpf_map_update_elem","bpf_map_delete_elem", ... ], ... } } v5: - In libbpf.map, move global symbol to the new LIBBPF_0.0.2 section. v4: - Use "enum bpf_func_id" instead of "__u32" in bpf_probe_helper() declaration for the type of the argument used to pass the id of the helper to probe. - Undef BPF_HELPER_MAKE_ENTRY after using it. v3: - Do not pass kernel version from bpftool to libbpf probes (kernel version for testing program with kprobes is retrieved directly from libbpf). - Dump one list of available helpers per program type (instead of one list of compatible program types per helper). v2: - Move probes from bpftool to libbpf. - Test all program types for each helper, print a list of working prog types for each helper. - Fall back on include/uapi/linux/bpf.h for names and ids of helpers. - Remove C-style macros output from this patch. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:55 +00:00
LIBBPF_API bool bpf_probe_helper(enum bpf_func_id id,
enum bpf_prog_type prog_type, __u32 ifindex);
LIBBPF_API bool bpf_probe_large_insn_limit(__u32 ifindex);
tools: bpftool: add probes for eBPF program types Introduce probes for supported BPF program types in libbpf, and call it from bpftool to test what types are available on the system. The probe simply consists in loading a very basic program of that type and see if the verifier complains or not. Sample output: # bpftool feature probe kernel ... Scanning eBPF program types... eBPF program_type socket_filter is available eBPF program_type kprobe is available eBPF program_type sched_cls is available ... # bpftool --json --pretty feature probe kernel { ... "program_types": { "have_socket_filter_prog_type": true, "have_kprobe_prog_type": true, "have_sched_cls_prog_type": true, ... } } v5: - In libbpf.map, move global symbol to a new LIBBPF_0.0.2 section. - Rename (non-API function) prog_load() as probe_load(). v3: - Get kernel version for checking kprobes availability from libbpf instead of from bpftool. Do not pass kernel_version as an argument when calling libbpf probes. - Use a switch with all enum values for setting specific program parameters just before probing, so that gcc complains at compile time (-Wswitch-enum) if new prog types were added to the kernel but libbpf was not updated. - Add a comment in libbpf.h about setrlimit() usage to allow many consecutive probe attempts. v2: - Move probes from bpftool to libbpf. - Remove C-style macros output from this patch. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:53 +00:00
/*
* Get bpf_prog_info in continuous memory
*
* struct bpf_prog_info has multiple arrays. The user has option to choose
* arrays to fetch from kernel. The following APIs provide an uniform way to
* fetch these data. All arrays in bpf_prog_info are stored in a single
* continuous memory region. This makes it easy to store the info in a
* file.
*
* Before writing bpf_prog_info_linear to files, it is necessary to
* translate pointers in bpf_prog_info to offsets. Helper functions
* bpf_program__bpil_addr_to_offs() and bpf_program__bpil_offs_to_addr()
* are introduced to switch between pointers and offsets.
*
* Examples:
* # To fetch map_ids and prog_tags:
* __u64 arrays = (1UL << BPF_PROG_INFO_MAP_IDS) |
* (1UL << BPF_PROG_INFO_PROG_TAGS);
* struct bpf_prog_info_linear *info_linear =
* bpf_program__get_prog_info_linear(fd, arrays);
*
* # To save data in file
* bpf_program__bpil_addr_to_offs(info_linear);
* write(f, info_linear, sizeof(*info_linear) + info_linear->data_len);
*
* # To read data from file
* read(f, info_linear, <proper_size>);
* bpf_program__bpil_offs_to_addr(info_linear);
*/
enum bpf_prog_info_array {
BPF_PROG_INFO_FIRST_ARRAY = 0,
BPF_PROG_INFO_JITED_INSNS = 0,
BPF_PROG_INFO_XLATED_INSNS,
BPF_PROG_INFO_MAP_IDS,
BPF_PROG_INFO_JITED_KSYMS,
BPF_PROG_INFO_JITED_FUNC_LENS,
BPF_PROG_INFO_FUNC_INFO,
BPF_PROG_INFO_LINE_INFO,
BPF_PROG_INFO_JITED_LINE_INFO,
BPF_PROG_INFO_PROG_TAGS,
BPF_PROG_INFO_LAST_ARRAY,
};
struct bpf_prog_info_linear {
/* size of struct bpf_prog_info, when the tool is compiled */
__u32 info_len;
/* total bytes allocated for data, round up to 8 bytes */
__u32 data_len;
/* which arrays are included in data */
__u64 arrays;
struct bpf_prog_info info;
__u8 data[];
};
LIBBPF_API struct bpf_prog_info_linear *
bpf_program__get_prog_info_linear(int fd, __u64 arrays);
LIBBPF_API void
bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear);
LIBBPF_API void
bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);
/*
* A helper function to get the number of possible CPUs before looking up
* per-CPU maps. Negative errno is returned on failure.
*
* Example usage:
*
* int ncpus = libbpf_num_possible_cpus();
* if (ncpus < 0) {
* // error handling
* }
* long values[ncpus];
* bpf_map_lookup_elem(per_cpu_map_fd, key, values);
*
*/
LIBBPF_API int libbpf_num_possible_cpus(void);
struct bpf_map_skeleton {
const char *name;
struct bpf_map **map;
void **mmaped;
};
struct bpf_prog_skeleton {
const char *name;
struct bpf_program **prog;
struct bpf_link **link;
};
struct bpf_object_skeleton {
size_t sz; /* size of this struct, for forward/backward compatibility */
const char *name;
void *data;
size_t data_sz;
struct bpf_object **obj;
int map_cnt;
int map_skel_sz; /* sizeof(struct bpf_skeleton_map) */
struct bpf_map_skeleton *maps;
int prog_cnt;
int prog_skel_sz; /* sizeof(struct bpf_skeleton_prog) */
struct bpf_prog_skeleton *progs;
};
LIBBPF_API int
bpf_object__open_skeleton(struct bpf_object_skeleton *s,
const struct bpf_object_open_opts *opts);
LIBBPF_API int bpf_object__load_skeleton(struct bpf_object_skeleton *s);
LIBBPF_API int bpf_object__attach_skeleton(struct bpf_object_skeleton *s);
LIBBPF_API void bpf_object__detach_skeleton(struct bpf_object_skeleton *s);
LIBBPF_API void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s);
libbpf: Support libbpf-provided extern variables Add support for extern variables, provided to BPF program by libbpf. Currently the following extern variables are supported: - LINUX_KERNEL_VERSION; version of a kernel in which BPF program is executing, follows KERNEL_VERSION() macro convention, can be 4- and 8-byte long; - CONFIG_xxx values; a set of values of actual kernel config. Tristate, boolean, strings, and integer values are supported. Set of possible values is determined by declared type of extern variable. Supported types of variables are: - Tristate values. Are represented as `enum libbpf_tristate`. Accepted values are **strictly** 'y', 'n', or 'm', which are represented as TRI_YES, TRI_NO, or TRI_MODULE, respectively. - Boolean values. Are represented as bool (_Bool) types. Accepted values are 'y' and 'n' only, turning into true/false values, respectively. - Single-character values. Can be used both as a substritute for bool/tristate, or as a small-range integer: - 'y'/'n'/'m' are represented as is, as characters 'y', 'n', or 'm'; - integers in a range [-128, 127] or [0, 255] (depending on signedness of char in target architecture) are recognized and represented with respective values of char type. - Strings. String values are declared as fixed-length char arrays. String of up to that length will be accepted and put in first N bytes of char array, with the rest of bytes zeroed out. If config string value is longer than space alloted, it will be truncated and warning message emitted. Char array is always zero terminated. String literals in config have to be enclosed in double quotes, just like C-style string literals. - Integers. 8-, 16-, 32-, and 64-bit integers are supported, both signed and unsigned variants. Libbpf enforces parsed config value to be in the supported range of corresponding integer type. Integers values in config can be: - decimal integers, with optional + and - signs; - hexadecimal integers, prefixed with 0x or 0X; - octal integers, starting with 0. Config file itself is searched in /boot/config-$(uname -r) location with fallback to /proc/config.gz, unless config path is specified explicitly through bpf_object_open_opts' kernel_config_path option. Both gzipped and plain text formats are supported. Libbpf adds explicit dependency on zlib because of this, but this shouldn't be a problem, given libelf already depends on zlib. All detected extern variables, are put into a separate .extern internal map. It, similarly to .rodata map, is marked as read-only from BPF program side, as well as is frozen on load. This allows BPF verifier to track extern values as constants and perform enhanced branch prediction and dead code elimination. This can be relied upon for doing kernel version/feature detection and using potentially unsupported field relocations or BPF helpers in a CO-RE-based BPF program, while still having a single version of BPF program running on old and new kernels. Selftests are validating this explicitly for unexisting BPF helper. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014710.3449601-3-andriin@fb.com
2019-12-14 01:47:08 +00:00
enum libbpf_tristate {
TRI_NO = 0,
TRI_YES = 1,
TRI_MODULE = 2,
};
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LIBBPF_LIBBPF_H */