diff options
| -rw-r--r-- | tools/lib/bpf/bpf.c | 34 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 3 |
2 files changed, 34 insertions, 3 deletions
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index cf27251adb92..a9d292c106c2 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -817,7 +817,7 @@ int bpf_link_create(int prog_fd, int target_fd, { __u32 target_btf_id, iter_info_len; union bpf_attr attr; - int fd; + int fd, err; if (!OPTS_VALID(opts, bpf_link_create_opts)) return libbpf_err(-EINVAL); @@ -870,7 +870,37 @@ int bpf_link_create(int prog_fd, int target_fd, } proceed: fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, sizeof(attr)); - return libbpf_err_errno(fd); + if (fd >= 0) + return fd; + /* we'll get EINVAL if LINK_CREATE doesn't support attaching fentry + * and other similar programs + */ + err = -errno; + if (err != -EINVAL) + return libbpf_err(err); + + /* if user used features not supported by + * BPF_RAW_TRACEPOINT_OPEN command, then just give up immediately + */ + if (attr.link_create.target_fd || attr.link_create.target_btf_id) + return libbpf_err(err); + if (!OPTS_ZEROED(opts, sz)) + return libbpf_err(err); + + /* otherwise, for few select kinds of programs that can be + * attached using BPF_RAW_TRACEPOINT_OPEN command, try that as + * a fallback for older kernels + */ + switch (attach_type) { + case BPF_TRACE_RAW_TP: + case BPF_LSM_MAC: + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + case BPF_MODIFY_RETURN: + return bpf_raw_tracepoint_open(NULL, prog_fd); + default: + return libbpf_err(err); + } } int bpf_link_detach(int link_fd) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 873a29ce7781..9a213aaaac8a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11260,7 +11260,8 @@ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *pro return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; - pfd = bpf_raw_tracepoint_open(NULL, prog_fd); + /* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */ + pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), NULL); if (pfd < 0) { pfd = -errno; free(link); |