perf trace: Read_tracing_data should die() another day

It better propagate errors, also if we do a simple:

[root@doppio linux-2.6-tip]# perf record -R -a -f sleep 3s ;
perf trace [ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.182 MB perf.data (~7972 samples) ]
Fatal: not an trace data file
[root@doppio linux-2.6-tip]#

That is what is expected, right? I.e. as we didn't specify any
tracepoint event via -e, it should gracefully bail out and not
SEGFAULT.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258821086-11521-3-git-send-email-acme@infradead.org>
[ Fixed the error messages some more ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/perf/util/trace-event-read.c b/tools/perf/util/trace-event-read.c
index 44292e06cca4..342dfdd43f87 100644
--- a/tools/perf/util/trace-event-read.c
+++ b/tools/perf/util/trace-event-read.c
@@ -471,11 +471,11 @@ void trace_report(int fd)
 
         read_or_die(buf, 3);
         if (memcmp(buf, test, 3) != 0)
-                die("not an trace data file");
+                die("no trace data in the file");
 
         read_or_die(buf, 7);
         if (memcmp(buf, "tracing", 7) != 0)
-                die("not a trace file (missing tracing)");
+                die("not a trace file (missing 'tracing' tag)");
 
         version = read_string();
         if (show_version)