diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2023-12-13 11:08:41 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-12-13 15:47:05 -0800 |
| commit | ed54124b88056fd629c6af71664dfcd4d3b3e0b8 (patch) | |
| tree | e93d0fe0e46fd6111b15a3ea58afaf3c34df0875 /tools/lib | |
| parent | 18678cf0ee13cf19bac4ecd55665e6d1d63108b3 (diff) | |
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 neither bpf_token_path nor bpf_token_fd
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>
Link: https://lore.kernel.org/r/20231213190842.3844987-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 14 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.h | 13 |
2 files changed, 21 insertions, 6 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index db94bbe163e3..4b5ff9508e18 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7171,11 +7171,17 @@ static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, /* non-empty token path can't be combined with invalid token FD */ if (token_path && token_path[0] != '\0' && token_fd < 0) return ERR_PTR(-EINVAL); + /* empty token path can't be combined with valid token FD */ + if (token_path && token_path[0] == '\0' && token_fd > 0) + return ERR_PTR(-EINVAL); + /* if user didn't specify bpf_token_path/bpf_token_fd explicitly, + * check if LIBBPF_BPF_TOKEN_PATH envvar was set and treat it as + * bpf_token_path option + */ + if (token_fd == 0 && !token_path) + token_path = getenv("LIBBPF_BPF_TOKEN_PATH"); + /* empty token_path is equivalent to invalid token_fd */ if (token_path && token_path[0] == '\0') { - /* empty token path can't be combined with valid token FD */ - if (token_fd > 0) - return ERR_PTR(-EINVAL); - /* empty token_path is equivalent to invalid token_fd */ token_path = NULL; token_fd = -1; } diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d3de39b537f3..916904bd2a7a 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -185,8 +185,16 @@ struct bpf_object_open_opts { * attempt to create BPF token from default BPF FS mount point * (/sys/fs/bpf), in case this default behavior is undesirable. * + * If bpf_token_path and bpf_token_fd are not specified, libbpf will + * consult LIBBPF_BPF_TOKEN_PATH environment variable. If set, it will + * be taken as a value of bpf_token_path option and will force libbpf + * to either create BPF token from provided custom BPF FS path, or + * will disable implicit BPF token creation, if envvar value is an + * empty string. + * * bpf_token_path and bpf_token_fd are mutually exclusive and only one - * of those options should be set. + * of those options should be set. Either of them overrides + * LIBBPF_BPF_TOKEN_PATH envvar. */ int bpf_token_fd; /* Path to BPF FS mount point to derive BPF token from. @@ -200,7 +208,8 @@ struct bpf_object_open_opts { * point (/sys/fs/bpf), in case this default behavior is undesirable. * * bpf_token_path and bpf_token_fd are mutually exclusive and only one - * of those options should be set. + * of those options should be set. Either of them overrides + * LIBBPF_BPF_TOKEN_PATH envvar. */ const char *bpf_token_path; |