1 files changed, 48 insertions, 1 deletions

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index deeaa5c1ed7d..9722d841abc0 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1113,6 +1113,52 @@ static int do_detach(int argc, char **argv)
 	return 0;
 }
 
+enum prog_tracelog_mode {
+	TRACE_STDOUT,
+	TRACE_STDERR,
+};
+
+static int
+prog_tracelog_stream(int prog_fd, enum prog_tracelog_mode mode)
+{
+	FILE *file = mode == TRACE_STDOUT ? stdout : stderr;
+	int stream_id = mode == TRACE_STDOUT ? 1 : 2;
+	char buf[512];
+	int ret;
+
+	ret = 0;
+	do {
+		ret = bpf_prog_stream_read(prog_fd, stream_id, buf, sizeof(buf), NULL);
+		if (ret > 0)
+			fwrite(buf, sizeof(buf[0]), ret, file);
+	} while (ret > 0);
+
+	fflush(file);
+	return ret ? -1 : 0;
+}
+
+static int do_tracelog_any(int argc, char **argv)
+{
+	enum prog_tracelog_mode mode;
+	int fd;
+
+	if (argc == 0)
+		return do_tracelog(argc, argv);
+	if (!is_prefix(*argv, "stdout") && !is_prefix(*argv, "stderr"))
+		usage();
+	mode = is_prefix(*argv, "stdout") ? TRACE_STDOUT : TRACE_STDERR;
+	NEXT_ARG();
+
+	if (!REQ_ARGS(2))
+		return -1;
+
+	fd = prog_parse_fd(&argc, &argv);
+	if (fd < 0)
+		return -1;
+
+	return prog_tracelog_stream(fd, mode);
+}
+
 static int check_single_stdin(char *file_data_in, char *file_ctx_in)
 {
 	if (file_data_in && file_ctx_in &&
@@ -2493,6 +2539,7 @@ static int do_help(int argc, char **argv)
 		"                         [repeat N]\n"
 		"       %1$s %2$s profile PROG [duration DURATION] METRICs\n"
 		"       %1$s %2$s tracelog\n"
+		"       %1$s %2$s tracelog { stdout | stderr } PROG\n"
 		"       %1$s %2$s help\n"
 		"\n"
 		"       " HELP_SPEC_MAP "\n"
@@ -2532,7 +2579,7 @@ static const struct cmd cmds[] = {
 	{ "loadall",	do_loadall },
 	{ "attach",	do_attach },
 	{ "detach",	do_detach },
-	{ "tracelog",	do_tracelog },
+	{ "tracelog",	do_tracelog_any },
 	{ "run",	do_run },
 	{ "profile",	do_profile },
 	{ 0 }