perf header: Recognize version number for perf data file

Keep the recognized data file version within 'struct perf_header'.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1374083403-14591-8-git-send-email-jolsa@redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/header.c

@@ -2480,6 +2480,7 @@ static int check_magic_endian(u64 magic, uint64_t hdr_sz,
 	/* check for legacy format */
 	ret = memcmp(&magic, __perf_magic1, sizeof(magic));
 	if (ret == 0) {
+		ph->version = PERF_HEADER_VERSION_1;
 		pr_debug("legacy perf.data format\n");
 		if (is_pipe)
 			return try_all_pipe_abis(hdr_sz, ph);
@@ -2501,6 +2502,7 @@ static int check_magic_endian(u64 magic, uint64_t hdr_sz,
 		return -1;
 
 	ph->needs_swap = true;
+	ph->version = PERF_HEADER_VERSION_2;
 
 	return 0;
 }

tools/perf/util/header.h

@@ -34,6 +34,11 @@ enum {
 	HEADER_FEAT_BITS	= 256,
 };
 
+enum perf_header_version {
+	PERF_HEADER_VERSION_1,
+	PERF_HEADER_VERSION_2,
+};
+
 struct perf_file_section {
 	u64 offset;
 	u64 size;
@@ -85,6 +90,7 @@ struct perf_session_env {
 };
 
 struct perf_header {
+	enum perf_header_version	version;
 	bool				needs_swap;
 	u64				data_offset;
 	u64				data_size;