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 10:13:51 +08:00
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/*
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* Common eBPF ELF object loading operations.
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*
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* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
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* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
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* Copyright (C) 2015 Huawei Inc.
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*/
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#ifndef __BPF_LIBBPF_H
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#define __BPF_LIBBPF_H
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2015-07-01 10:13:53 +08:00
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#include <stdio.h>
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2015-07-01 10:14:08 +08:00
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#include <stdbool.h>
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2015-11-06 21:49:37 +08:00
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#include <linux/err.h>
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enum libbpf_errno {
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__LIBBPF_ERRNO__START = 4000,
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/* Something wrong in libelf */
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LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
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LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */
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LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */
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LIBBPF_ERRNO__ENDIAN, /* Endian missmatch */
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LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */
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LIBBPF_ERRNO__RELOC, /* Relocation failed */
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LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */
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LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */
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LIBBPF_ERRNO__PROG2BIG, /* Program too big */
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LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
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__LIBBPF_ERRNO__END,
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};
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int libbpf_strerror(int err, char *buf, size_t size);
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2015-07-01 10:13:53 +08:00
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2015-07-01 10:13:52 +08:00
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/*
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* In include/linux/compiler-gcc.h, __printf is defined. However
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* it should be better if libbpf.h doesn't depend on Linux header file.
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* So instead of __printf, here we use gcc attribute directly.
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*/
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typedef int (*libbpf_print_fn_t)(const char *, ...)
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__attribute__((format(printf, 1, 2)));
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void libbpf_set_print(libbpf_print_fn_t warn,
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libbpf_print_fn_t info,
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libbpf_print_fn_t debug);
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2015-07-01 10:13:53 +08:00
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/* Hide internal to user */
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struct bpf_object;
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struct bpf_object *bpf_object__open(const char *path);
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2015-07-01 10:13:54 +08:00
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struct bpf_object *bpf_object__open_buffer(void *obj_buf,
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2015-08-27 10:30:55 +08:00
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size_t obj_buf_sz,
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const char *name);
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2015-07-01 10:13:53 +08:00
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void bpf_object__close(struct bpf_object *object);
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2015-07-01 10:14:04 +08:00
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/* Load/unload object into/from kernel */
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int bpf_object__load(struct bpf_object *obj);
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int bpf_object__unload(struct bpf_object *obj);
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2016-06-03 23:22:51 +08:00
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const char *bpf_object__name(struct bpf_object *obj);
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unsigned int bpf_object__kversion(struct bpf_object *obj);
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2015-07-01 10:14:04 +08:00
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2015-07-01 10:14:10 +08:00
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struct bpf_object *bpf_object__next(struct bpf_object *prev);
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#define bpf_object__for_each_safe(pos, tmp) \
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for ((pos) = bpf_object__next(NULL), \
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(tmp) = bpf_object__next(pos); \
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(pos) != NULL; \
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(pos) = (tmp), (tmp) = bpf_object__next(tmp))
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2015-07-01 10:14:08 +08:00
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/* Accessors of bpf_program. */
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struct bpf_program;
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struct bpf_program *bpf_program__next(struct bpf_program *prog,
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struct bpf_object *obj);
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#define bpf_object__for_each_program(pos, obj) \
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for ((pos) = bpf_program__next(NULL, (obj)); \
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(pos) != NULL; \
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(pos) = bpf_program__next((pos), (obj)))
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typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
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void *);
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2016-06-03 23:38:21 +08:00
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int bpf_program__set_priv(struct bpf_program *prog, void *priv,
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bpf_program_clear_priv_t clear_priv);
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2015-07-01 10:14:08 +08:00
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2016-06-03 23:36:39 +08:00
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void *bpf_program__priv(struct bpf_program *prog);
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2015-07-01 10:14:08 +08:00
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2015-11-03 19:21:05 +08:00
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const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
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2015-07-01 10:14:08 +08:00
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int bpf_program__fd(struct bpf_program *prog);
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2015-11-16 20:10:09 +08:00
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struct bpf_insn;
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/*
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* Libbpf allows callers to adjust BPF programs before being loaded
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* into kernel. One program in an object file can be transform into
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* multiple variants to be attached to different code.
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*
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* bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
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* are APIs for this propose.
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*
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* - bpf_program_prep_t:
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* It defines 'preprocessor', which is a caller defined function
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* passed to libbpf through bpf_program__set_prep(), and will be
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* called before program is loaded. The processor should adjust
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* the program one time for each instances according to the number
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* passed to it.
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*
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* - bpf_program__set_prep:
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* Attachs a preprocessor to a BPF program. The number of instances
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* whould be created is also passed through this function.
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*
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* - bpf_program__nth_fd:
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* After the program is loaded, get resuling fds from bpf program for
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* each instances.
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*
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* If bpf_program__set_prep() is not used, the program whould be loaded
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* without adjustment during bpf_object__load(). The program has only
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* one instance. In this case bpf_program__fd(prog) is equal to
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* bpf_program__nth_fd(prog, 0).
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*/
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struct bpf_prog_prep_result {
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/*
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* If not NULL, load new instruction array.
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* If set to NULL, don't load this instance.
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*/
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struct bpf_insn *new_insn_ptr;
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int new_insn_cnt;
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/* If not NULL, result fd is set to it */
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int *pfd;
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};
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/*
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* Parameters of bpf_program_prep_t:
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* - prog: The bpf_program being loaded.
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* - n: Index of instance being generated.
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* - insns: BPF instructions array.
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* - insns_cnt:Number of instructions in insns.
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* - res: Output parameter, result of transformation.
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*
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* Return value:
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* - Zero: pre-processing success.
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* - Non-zero: pre-processing, stop loading.
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*/
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typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
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struct bpf_insn *insns, int insns_cnt,
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struct bpf_prog_prep_result *res);
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int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
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bpf_program_prep_t prep);
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int bpf_program__nth_fd(struct bpf_program *prog, int n);
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2015-07-01 10:14:02 +08:00
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/*
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* We don't need __attribute__((packed)) now since it is
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* unnecessary for 'bpf_map_def' because they are all aligned.
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* In addition, using it will trigger -Wpacked warning message,
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* and will be treated as an error due to -Werror.
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*/
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struct bpf_map_def {
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unsigned int type;
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unsigned int key_size;
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unsigned int value_size;
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unsigned int max_entries;
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};
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2015-11-27 16:47:35 +08:00
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/*
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* There is another 'struct bpf_map' in include/linux/map.h. However,
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* it is not a uapi header so no need to consider name clash.
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*/
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struct bpf_map;
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2015-11-27 16:47:36 +08:00
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struct bpf_map *
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2016-06-03 23:22:51 +08:00
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bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
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2015-11-27 16:47:35 +08:00
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struct bpf_map *
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bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
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#define bpf_map__for_each(pos, obj) \
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for ((pos) = bpf_map__next(NULL, (obj)); \
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(pos) != NULL; \
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(pos) = bpf_map__next((pos), (obj)))
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2016-06-03 23:15:52 +08:00
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int bpf_map__fd(struct bpf_map *map);
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2016-06-03 01:21:06 +08:00
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const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
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2016-06-02 22:02:05 +08:00
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const char *bpf_map__name(struct bpf_map *map);
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2015-11-27 16:47:35 +08:00
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typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
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2016-06-03 23:38:21 +08:00
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int bpf_map__set_priv(struct bpf_map *map, void *priv,
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bpf_map_clear_priv_t clear_priv);
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2016-06-02 21:51:59 +08:00
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void *bpf_map__priv(struct bpf_map *map);
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2015-11-27 16:47:35 +08:00
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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 10:13:51 +08:00
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#endif
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