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-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-prog.rst13
-rw-r--r--tools/bpf/bpftool/bash-completion/bpftool5
-rw-r--r--tools/bpf/bpftool/main.h1
-rw-r--r--tools/bpf/bpftool/prog.c4
-rw-r--r--tools/bpf/bpftool/tracelog.c157
5 files changed, 176 insertions, 4 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index ab36e920e552..5524b6dccd85 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -26,8 +26,9 @@ MAP COMMANDS
| **bpftool** **prog dump jited** *PROG* [{**file** *FILE* | **opcodes**}]
| **bpftool** **prog pin** *PROG* *FILE*
| **bpftool** **prog { load | loadall }** *OBJ* *PATH* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*]
-| **bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
-| **bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
+| **bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
+| **bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
+| **bpftool** **prog tracelog**
| **bpftool** **prog help**
|
| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
@@ -117,6 +118,14 @@ DESCRIPTION
parameter, with the exception of *flow_dissector* which is
detached from the current networking name space.
+ **bpftool prog tracelog**
+ Dump the trace pipe of the system to the console (stdout).
+ Hit <Ctrl+C> to stop printing. BPF programs can write to this
+ trace pipe at runtime with the **bpf_trace_printk()** helper.
+ This should be used only for debugging purposes. For
+ streaming data from BPF programs to user space, one can use
+ perf events (see also **bpftool-map**\ (8)).
+
**bpftool prog help**
Print short help message.
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 9a60080f085f..44c189ba072a 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -398,10 +398,13 @@ _bpftool()
;;
esac
;;
+ tracelog)
+ return 0
+ ;;
*)
[[ $prev == $object ]] && \
COMPREPLY=( $( compgen -W 'dump help pin attach detach load \
- show list' -- "$cur" ) )
+ show list tracelog' -- "$cur" ) )
;;
esac
;;
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 2761981669c8..0be0dd8f467f 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -167,6 +167,7 @@ int do_event_pipe(int argc, char **argv);
int do_cgroup(int argc, char **arg);
int do_perf(int argc, char **arg);
int do_net(int argc, char **arg);
+int do_tracelog(int argc, char **arg);
int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
int prog_parse_fd(int *argc, char ***argv);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 56db61c5a91f..54c8dbf05c9c 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1140,6 +1140,7 @@ static int do_help(int argc, char **argv)
" [pinmaps MAP_DIR]\n"
" %s %s attach PROG ATTACH_TYPE [MAP]\n"
" %s %s detach PROG ATTACH_TYPE [MAP]\n"
+ " %s %s tracelog\n"
" %s %s help\n"
"\n"
" " HELP_SPEC_MAP "\n"
@@ -1158,7 +1159,7 @@ static int do_help(int argc, char **argv)
"",
bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
- bin_name, argv[-2], bin_name, argv[-2]);
+ bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);
return 0;
}
@@ -1173,6 +1174,7 @@ static const struct cmd cmds[] = {
{ "loadall", do_loadall },
{ "attach", do_attach },
{ "detach", do_detach },
+ { "tracelog", do_tracelog },
{ 0 }
};
diff --git a/tools/bpf/bpftool/tracelog.c b/tools/bpf/bpftool/tracelog.c
new file mode 100644
index 000000000000..1fa8e513f590
--- /dev/null
+++ b/tools/bpf/bpftool/tracelog.c
@@ -0,0 +1,157 @@
+// 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 find_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))
+ 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];
+ bool found_trace_pipe;
+ size_t buff_len = 0;
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+
+ found_trace_pipe = find_tracefs_pipe(trace_pipe);
+ if (!found_trace_pipe) {
+ p_err("could not find trace pipe, tracefs not mounted?");
+ 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 16:38:11 +0000