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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/bpf/bpftool/tracelog.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | tools/bpf/bpftool/tracelog.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/tracelog.c b/tools/bpf/bpftool/tracelog.c new file mode 100644 index 000000000..e80a5c79b --- /dev/null +++ b/tools/bpf/bpftool/tracelog.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (c) 2015-2017 Daniel Borkmann */ +/* Copyright (c) 2018 Netronome Systems, Inc. */ + +#include <errno.h> +#include <limits.h> +#include <signal.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <linux/magic.h> +#include <sys/fcntl.h> +#include <sys/vfs.h> + +#include "main.h" + +#ifndef TRACEFS_MAGIC +# define TRACEFS_MAGIC 0x74726163 +#endif + +#define _textify(x) #x +#define textify(x) _textify(x) + +FILE *trace_pipe_fd; +char *buff; + +static int validate_tracefs_mnt(const char *mnt, unsigned long magic) +{ + struct statfs st_fs; + + if (statfs(mnt, &st_fs) < 0) + return -ENOENT; + if ((unsigned long)st_fs.f_type != magic) + return -ENOENT; + + return 0; +} + +static bool +find_tracefs_mnt_single(unsigned long magic, char *mnt, const char *mntpt) +{ + size_t src_len; + + if (validate_tracefs_mnt(mntpt, magic)) + return false; + + src_len = strlen(mntpt); + if (src_len + 1 >= PATH_MAX) { + p_err("tracefs mount point name too long"); + return false; + } + + strcpy(mnt, mntpt); + return true; +} + +static bool get_tracefs_pipe(char *mnt) +{ + static const char * const known_mnts[] = { + "/sys/kernel/debug/tracing", + "/sys/kernel/tracing", + "/tracing", + "/trace", + }; + const char *pipe_name = "/trace_pipe"; + const char *fstype = "tracefs"; + char type[100], format[32]; + const char * const *ptr; + bool found = false; + FILE *fp; + + for (ptr = known_mnts; ptr < known_mnts + ARRAY_SIZE(known_mnts); ptr++) + if (find_tracefs_mnt_single(TRACEFS_MAGIC, mnt, *ptr)) + goto exit_found; + + fp = fopen("/proc/mounts", "r"); + if (!fp) + return false; + + /* Allow room for NULL terminating byte and pipe file name */ + snprintf(format, sizeof(format), "%%*s %%%zds %%99s %%*s %%*d %%*d\\n", + PATH_MAX - strlen(pipe_name) - 1); + while (fscanf(fp, format, mnt, type) == 2) + if (strcmp(type, fstype) == 0) { + found = true; + break; + } + fclose(fp); + + /* The string from fscanf() might be truncated, check mnt is valid */ + if (found && validate_tracefs_mnt(mnt, TRACEFS_MAGIC)) + goto exit_found; + + if (block_mount) + return false; + + p_info("could not find tracefs, attempting to mount it now"); + /* Most of the time, tracefs is automatically mounted by debugfs at + * /sys/kernel/debug/tracing when we try to access it. If we could not + * find it, it is likely that debugfs is not mounted. Let's give one + * attempt at mounting just tracefs at /sys/kernel/tracing. + */ + strcpy(mnt, known_mnts[1]); + if (mount_tracefs(mnt)) + return false; + +exit_found: + strcat(mnt, pipe_name); + return true; +} + +static void exit_tracelog(int signum) +{ + fclose(trace_pipe_fd); + free(buff); + + if (json_output) { + jsonw_end_array(json_wtr); + jsonw_destroy(&json_wtr); + } + + exit(0); +} + +int do_tracelog(int argc, char **argv) +{ + const struct sigaction act = { + .sa_handler = exit_tracelog + }; + char trace_pipe[PATH_MAX]; + size_t buff_len = 0; + + if (json_output) + jsonw_start_array(json_wtr); + + if (!get_tracefs_pipe(trace_pipe)) + return -1; + + trace_pipe_fd = fopen(trace_pipe, "r"); + if (!trace_pipe_fd) { + p_err("could not open trace pipe: %s", strerror(errno)); + return -1; + } + + sigaction(SIGHUP, &act, NULL); + sigaction(SIGINT, &act, NULL); + sigaction(SIGTERM, &act, NULL); + while (1) { + ssize_t ret; + + ret = getline(&buff, &buff_len, trace_pipe_fd); + if (ret <= 0) { + p_err("failed to read content from trace pipe: %s", + strerror(errno)); + break; + } + if (json_output) + jsonw_string(json_wtr, buff); + else + printf("%s", buff); + } + + fclose(trace_pipe_fd); + free(buff); + return -1; +} |