diff options
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 79 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.h | 4 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 1 |
3 files changed, 84 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b5b49ddb152f..85174fcd99e0 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4190,6 +4190,85 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, return link; } +static int determine_tracepoint_id(const char *tp_category, + const char *tp_name) +{ + char file[PATH_MAX]; + int ret; + + ret = snprintf(file, sizeof(file), + "/sys/kernel/debug/tracing/events/%s/%s/id", + tp_category, tp_name); + if (ret < 0) + return -errno; + if (ret >= sizeof(file)) { + pr_debug("tracepoint %s/%s path is too long\n", + tp_category, tp_name); + return -E2BIG; + } + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_open_tracepoint(const char *tp_category, + const char *tp_name) +{ + struct perf_event_attr attr = {}; + char errmsg[STRERR_BUFSIZE]; + int tp_id, pfd, err; + + tp_id = determine_tracepoint_id(tp_category, tp_name); + if (tp_id < 0) { + pr_warning("failed to determine tracepoint '%s/%s' perf event ID: %s\n", + tp_category, tp_name, + libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg))); + return tp_id; + } + + attr.type = PERF_TYPE_TRACEPOINT; + attr.size = sizeof(attr); + attr.config = tp_id; + + pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */, + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (pfd < 0) { + err = -errno; + pr_warning("tracepoint '%s/%s' perf_event_open() failed: %s\n", + tp_category, tp_name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return err; + } + return pfd; +} + +struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, + const char *tp_category, + const char *tp_name) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int pfd, err; + + pfd = perf_event_open_tracepoint(tp_category, tp_name); + if (pfd < 0) { + pr_warning("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n", + bpf_program__title(prog, false), + tp_category, tp_name, + libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link = bpf_program__attach_perf_event(prog, pfd); + if (IS_ERR(link)) { + close(pfd); + err = PTR_ERR(link); + pr_warning("program '%s': failed to attach to tracepoint '%s/%s': %s\n", + bpf_program__title(prog, false), + tp_category, tp_name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return link; + } + return link; +} + enum bpf_perf_event_ret bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, void **copy_mem, size_t *copy_size, diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index bd767cc11967..60611f4b4e1d 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -178,6 +178,10 @@ LIBBPF_API struct bpf_link * bpf_program__attach_uprobe(struct bpf_program *prog, bool retprobe, pid_t pid, const char *binary_path, size_t func_offset); +LIBBPF_API struct bpf_link * +bpf_program__attach_tracepoint(struct bpf_program *prog, + const char *tp_category, + const char *tp_name); struct bpf_insn; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 57a40fb60718..3c618b75ef65 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -171,6 +171,7 @@ LIBBPF_0.0.4 { bpf_object__load_xattr; bpf_program__attach_kprobe; bpf_program__attach_perf_event; + bpf_program__attach_tracepoint; bpf_program__attach_uprobe; btf_dump__dump_type; btf_dump__free; |