perf inject: Fix output from a file to a pipe

When the input is a regular file but the output is a pipe, it should
write a pipe header.  But just repiping would write a portion of the
existing header which is different in 'size' value.  So we need to
prevent it and write a new pipe header along with other information
like event attributes and features.

This can handle something like this:

  # perf record -a -B sleep 1

  # perf inject -b -i perf.data | perf report -i -

Factor out perf_event__synthesize_for_pipe() to be shared between perf
record and inject.

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/20210719223153.1618812-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 4 insertions, 34 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 472cd12f10c6..548c1dbde6c5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1387,7 +1387,6 @@ static int record__synthesize(struct record *rec, bool tail)
 	struct perf_data *data = &rec->data;
 	struct record_opts *opts = &rec->opts;
 	struct perf_tool *tool = &rec->tool;
-	int fd = perf_data__fd(data);
 	int err = 0;
 	event_op f = process_synthesized_event;
 
@@ -1395,41 +1394,12 @@ static int record__synthesize(struct record *rec, bool tail)
 		return 0;
 
 	if (data->is_pipe) {
-		/*
-		 * We need to synthesize events first, because some
-		 * features works on top of them (on report side).
-		 */
-		err = perf_event__synthesize_attrs(tool, rec->evlist,
-						   process_synthesized_event);
-		if (err < 0) {
-			pr_err("Couldn't synthesize attrs.\n");
-			goto out;
-		}
-
-		err = perf_event__synthesize_features(tool, session, rec->evlist,
+		err = perf_event__synthesize_for_pipe(tool, session, data,
 						      process_synthesized_event);
-		if (err < 0) {
-			pr_err("Couldn't synthesize features.\n");
-			return err;
-		}
+		if (err < 0)
+			goto out;
 
-		if (have_tracepoints(&rec->evlist->core.entries)) {
-			/*
-			 * FIXME err <= 0 here actually means that
-			 * there were no tracepoints so its not really
-			 * an error, just that we don't need to
-			 * synthesize anything.  We really have to
-			 * return this more properly and also
-			 * propagate errors that now are calling die()
-			 */
-			err = perf_event__synthesize_tracing_data(tool,	fd, rec->evlist,
-								  process_synthesized_event);
-			if (err <= 0) {
-				pr_err("Couldn't record tracing data.\n");
-				goto out;
-			}
-			rec->bytes_written += err;
-		}
+		rec->bytes_written += err;
 	}
 
 	err = perf_event__synth_time_conv(record__pick_pc(rec), tool,