perf tools: Pass a fd to perf_file_header__read_pipe()

Currently it unconditionally writes to stdout for repipe.  But perf
inject can direct its output to a regular file.  Then it needs to
write the header to the file as well.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210719223153.1618812-3-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-inject.c

@@ -992,7 +992,8 @@ int cmd_inject(int argc, const char **argv)
 	}
 
 	data.path = inject.input_name;
-	inject.session = __perf_session__new(&data, inject.output.is_pipe, &inject.tool);
+	inject.session = __perf_session__new(&data, inject.output.is_pipe,
+					     perf_data__fd(&inject.output), &inject.tool);
 	if (IS_ERR(inject.session)) {
 		ret = PTR_ERR(inject.session);
 		goto out_close_output;

tools/perf/util/header.c

@@ -3865,10 +3865,10 @@ static int perf_file_section__process(struct perf_file_section *section,
 static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
 				       struct perf_header *ph,
 				       struct perf_data* data,
-				       bool repipe)
+				       bool repipe, int repipe_fd)
 {
 	struct feat_fd ff = {
-		.fd = STDOUT_FILENO,
+		.fd = repipe_fd,
 		.ph = ph,
 	};
 	ssize_t ret;
@@ -3891,13 +3891,13 @@ static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
 	return 0;
 }
 
-static int perf_header__read_pipe(struct perf_session *session)
+static int perf_header__read_pipe(struct perf_session *session, int repipe_fd)
 {
 	struct perf_header *header = &session->header;
 	struct perf_pipe_file_header f_header;
 
 	if (perf_file_header__read_pipe(&f_header, header, session->data,
-					session->repipe) < 0) {
+					session->repipe, repipe_fd) < 0) {
 		pr_debug("incompatible file format\n");
 		return -EINVAL;
 	}
@@ -3995,7 +3995,7 @@ static int evlist__prepare_tracepoint_events(struct evlist *evlist, struct tep_h
 	return 0;
 }
 
-int perf_session__read_header(struct perf_session *session)
+int perf_session__read_header(struct perf_session *session, int repipe_fd)
 {
 	struct perf_data *data = session->data;
 	struct perf_header *header = &session->header;
@@ -4016,7 +4016,7 @@ int perf_session__read_header(struct perf_session *session)
 	 * We can read 'pipe' data event from regular file,
 	 * check for the pipe header regardless of source.
 	 */
-	err = perf_header__read_pipe(session);
+	err = perf_header__read_pipe(session, repipe_fd);
 	if (!err || perf_data__is_pipe(data)) {
 		data->is_pipe = true;
 		return err;

tools/perf/util/header.h

@@ -115,7 +115,7 @@ struct perf_session;
 struct perf_tool;
 union perf_event;
 
-int perf_session__read_header(struct perf_session *session);
+int perf_session__read_header(struct perf_session *session, int repipe_fd);
 int perf_session__write_header(struct perf_session *session,
 			       struct evlist *evlist,
 			       int fd, bool at_exit);

tools/perf/util/session.c

@@ -102,11 +102,11 @@ static int perf_session__deliver_event(struct perf_session *session,
 				       struct perf_tool *tool,
 				       u64 file_offset);
 
-static int perf_session__open(struct perf_session *session)
+static int perf_session__open(struct perf_session *session, int repipe_fd)
 {
 	struct perf_data *data = session->data;
 
-	if (perf_session__read_header(session) < 0) {
+	if (perf_session__read_header(session, repipe_fd) < 0) {
 		pr_err("incompatible file format (rerun with -v to learn more)\n");
 		return -1;
 	}
@@ -186,7 +186,7 @@ static int ordered_events__deliver_event(struct ordered_events *oe,
 }
 
 struct perf_session *__perf_session__new(struct perf_data *data,
-					 bool repipe,
+					 bool repipe, int repipe_fd,
 					 struct perf_tool *tool)
 {
 	int ret = -ENOMEM;
@@ -211,7 +211,7 @@ struct perf_session *__perf_session__new(struct perf_data *data,
 		session->data = data;
 
 		if (perf_data__is_read(data)) {
-			ret = perf_session__open(session);
+			ret = perf_session__open(session, repipe_fd);
 			if (ret < 0)
 				goto out_delete;
 

tools/perf/util/session.h

@@ -55,13 +55,13 @@ struct decomp {
 struct perf_tool;
 
 struct perf_session *__perf_session__new(struct perf_data *data,
-					 bool repipe,
+					 bool repipe, int repipe_fd,
 					 struct perf_tool *tool);
 
 static inline struct perf_session *perf_session__new(struct perf_data *data,
 						     struct perf_tool *tool)
 {
-	return __perf_session__new(data, false, tool);
+	return __perf_session__new(data, false, -1, tool);
 }
 
 void perf_session__delete(struct perf_session *session);