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bpf: Append prog->aux->name in bpf_get_prog_name()

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This patch makes the bpf_prog's name available
in kallsyms.

The new format is bpf_prog_tag[_name].

Sample kallsyms from running selftests/bpf/test_progs:
[root@arch-fb-vm1 ~]# egrep ' bpf_prog_[0-9a-fA-F]{16}' /proc/kallsyms
ffffffffa0048000 t bpf_prog_dabf0207d1992486_test_obj_id
ffffffffa0038000 t bpf_prog_a04f5eef06a7f555__123456789ABCDE
ffffffffa0050000 t bpf_prog_a04f5eef06a7f555

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2017-10-05 21:52:13 -07:00 committed by David S. Miller
parent 067cae4777
commit 368211fb92
1 changed files with 15 additions and 2 deletions
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17
kernel/bpf/core.c
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@ -309,12 +309,25 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog,
static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
{
const char *end = sym + KSYM_NAME_LEN;
BUILD_BUG_ON(sizeof("bpf_prog_") +
sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
sizeof(prog->tag) * 2 +
/* name has been null terminated.
* We should need +1 for the '_' preceding
* the name. However, the null character
* is double counted between the name and the
* sizeof("bpf_prog_") above, so we omit
* the +1 here.
*/
sizeof(prog->aux->name) > KSYM_NAME_LEN);
sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
*sym = 0;
if (prog->aux->name[0])
snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
else
*sym = 0;
}
static __always_inline unsigned long