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author | Wang Nan <wangnan0@huawei.com> | 2015-07-01 02:14:00 (GMT) |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-08-07 13:16:57 (GMT) |
commit | a5b8bd47dcc574cd3a71357b3a0f586969e4b887 (patch) | |
tree | 074dd50dc1e87d168180a224d220411af32ec570 /tools/lib | |
parent | bec7d68cb561e94f8a44c2b73c468b534c05f20d (diff) | |
download | linux-a5b8bd47dcc574cd3a71357b3a0f586969e4b887.tar.xz |
bpf tools: Collect eBPF programs from their own sections
This patch collects all programs in an object file into an array of
'struct bpf_program' for further processing. That structure is for
representing each eBPF program. 'bpf_prog' should be a better name, but
it has been used by linux/filter.h. Although it is a kernel space name,
I still prefer to call it 'bpf_program' to prevent possible confusion.
bpf_object__add_program() creates a new 'struct bpf_program' object.
It first init a variable in stack using bpf_program__init(), then if
success, enlarges obj->programs array and copy the new object in.
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/1435716878-189507-13-git-send-email-wangnan0@huawei.com
[ Made bpf_object__add_program() propagate the error (-EINVAL or -ENOMEM) ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/lib')
-rw-r--r-- | tools/lib/bpf/libbpf.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9b016c0..102156f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -78,12 +78,27 @@ void libbpf_set_print(libbpf_print_fn_t warn, # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ #endif +/* + * bpf_prog should be a better name but it has been used in + * linux/filter.h. + */ +struct bpf_program { + /* Index in elf obj file, for relocation use. */ + int idx; + char *section_name; + struct bpf_insn *insns; + size_t insns_cnt; +}; + struct bpf_object { char license[64]; u32 kern_version; void *maps_buf; size_t maps_buf_sz; + struct bpf_program *programs; + size_t nr_programs; + /* * Information when doing elf related work. Only valid if fd * is valid. @@ -100,6 +115,85 @@ struct bpf_object { }; #define obj_elf_valid(o) ((o)->efile.elf) +static void bpf_program__exit(struct bpf_program *prog) +{ + if (!prog) + return; + + zfree(&prog->section_name); + zfree(&prog->insns); + prog->insns_cnt = 0; + prog->idx = -1; +} + +static int +bpf_program__init(void *data, size_t size, char *name, int idx, + struct bpf_program *prog) +{ + if (size < sizeof(struct bpf_insn)) { + pr_warning("corrupted section '%s'\n", name); + return -EINVAL; + } + + bzero(prog, sizeof(*prog)); + + prog->section_name = strdup(name); + if (!prog->section_name) { + pr_warning("failed to alloc name for prog %s\n", + name); + goto errout; + } + + prog->insns = malloc(size); + if (!prog->insns) { + pr_warning("failed to alloc insns for %s\n", name); + goto errout; + } + prog->insns_cnt = size / sizeof(struct bpf_insn); + memcpy(prog->insns, data, + prog->insns_cnt * sizeof(struct bpf_insn)); + prog->idx = idx; + + return 0; +errout: + bpf_program__exit(prog); + return -ENOMEM; +} + +static int +bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, + char *name, int idx) +{ + struct bpf_program prog, *progs; + int nr_progs, err; + + err = bpf_program__init(data, size, name, idx, &prog); + if (err) + return err; + + progs = obj->programs; + nr_progs = obj->nr_programs; + + progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1)); + if (!progs) { + /* + * In this case the original obj->programs + * is still valid, so don't need special treat for + * bpf_close_object(). + */ + pr_warning("failed to alloc a new program '%s'\n", + name); + bpf_program__exit(&prog); + return -ENOMEM; + } + + pr_debug("found program %s\n", prog.section_name); + obj->programs = progs; + obj->nr_programs = nr_progs + 1; + progs[nr_progs] = prog; + return 0; +} + static struct bpf_object *bpf_object__new(const char *path, void *obj_buf, size_t obj_buf_sz) @@ -342,6 +436,17 @@ static int bpf_object__elf_collect(struct bpf_object *obj) err = -EEXIST; } else obj->efile.symbols = data; + } else if ((sh.sh_type == SHT_PROGBITS) && + (sh.sh_flags & SHF_EXECINSTR) && + (data->d_size > 0)) { + err = bpf_object__add_program(obj, data->d_buf, + data->d_size, name, idx); + if (err) { + char errmsg[128]; + strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warning("failed to alloc program %s (%s): %s", + name, obj->path, errmsg); + } } if (err) goto out; @@ -415,11 +520,20 @@ struct bpf_object *bpf_object__open_buffer(void *obj_buf, void bpf_object__close(struct bpf_object *obj) { + size_t i; + if (!obj) return; bpf_object__elf_finish(obj); zfree(&obj->maps_buf); + + if (obj->programs && obj->nr_programs) { + for (i = 0; i < obj->nr_programs; i++) + bpf_program__exit(&obj->programs[i]); + } + zfree(&obj->programs); + free(obj); } |