libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvar

To allow external admin authority to override default BPF FS location
(/sys/fs/bpf) for implicit BPF token creation, teach libbpf to recognize
LIBBPF_BPF_TOKEN_PATH envvar. If it is specified and user application
didn't explicitly specify bpf_token_path option, it will be treated
exactly like bpf_token_path option, overriding default /sys/fs/bpf
location and making BPF token mandatory.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-29-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
2024-01-23 18:21:25 -08:00
committed by Andrii Nakryiko
parent e1a43809a9
commit a36646e2b3
2 changed files with 14 additions and 0 deletions

View File

@@ -7604,6 +7604,12 @@ static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf,
return ERR_PTR(-EINVAL);
token_path = OPTS_GET(opts, bpf_token_path, NULL);
/* if user didn't specify bpf_token_path explicitly, check if
* LIBBPF_BPF_TOKEN_PATH envvar was set and treat it as bpf_token_path
* option
*/
if (!token_path)
token_path = getenv("LIBBPF_BPF_TOKEN_PATH");
if (token_path && strlen(token_path) >= PATH_MAX)
return ERR_PTR(-ENAMETOOLONG);