215 lines
7 KiB
C
215 lines
7 KiB
C
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License (not later!)
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, see <http://www.gnu.org/licenses>
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*/
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#ifndef __BPF_LIBBPF_H
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#define __BPF_LIBBPF_H
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#include <stdio.h>
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#include <stdbool.h>
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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 mismatch */
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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__PROGTYPE, /* Kernel doesn't support this program type */
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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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/*
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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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/* 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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struct bpf_object *bpf_object__open_buffer(void *obj_buf,
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size_t obj_buf_sz,
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const char *name);
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void bpf_object__close(struct bpf_object *object);
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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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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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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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/* 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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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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void *bpf_program__priv(struct bpf_program *prog);
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const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
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int bpf_program__fd(struct bpf_program *prog);
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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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/*
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* Adjust type of bpf program. Default is kprobe.
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*/
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int bpf_program__set_tracepoint(struct bpf_program *prog);
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int bpf_program__set_kprobe(struct bpf_program *prog);
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bool bpf_program__is_tracepoint(struct bpf_program *prog);
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bool bpf_program__is_kprobe(struct bpf_program *prog);
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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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/*
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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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struct bpf_map *
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bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
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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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int bpf_map__fd(struct bpf_map *map);
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const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
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const char *bpf_map__name(struct bpf_map *map);
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typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
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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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void *bpf_map__priv(struct bpf_map *map);
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#endif
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