perf evlist: Support using -f to override perf.data file ownership

Enable perf evlist to use perf.data when it is not owned by current user
or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 10:18 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
   Error: unknown switch `f'

  usage: perf evlist [<options>]

     -i, --input <file>    Input file name
     -F, --freq            Show the sample frequency
     -v, --verbose         Show all event attr details
     -g, --group           Show event group information

As shown above, the -f option does not work at all.

After this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
 cycles

As shown above, the -f option really works now.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-2-git-send-email-yunlong.song@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-evlist.c

@@ -24,6 +24,7 @@ static int __cmd_evlist(const char *file_name, struct perf_attr_details *details
 	struct perf_data_file file = {
 		.path = file_name,
 		.mode = PERF_DATA_MODE_READ,
+		.force = details->force,
 	};
 
 	session = perf_session__new(&file, 0, NULL);
@@ -47,6 +48,7 @@ int cmd_evlist(int argc, const char **argv, const char *prefix __maybe_unused)
 		    "Show all event attr details"),
 	OPT_BOOLEAN('g', "group", &details.event_group,
 		    "Show event group information"),
+	OPT_BOOLEAN('f', "force", &details.force, "don't complain, do it"),
 	OPT_END()
 	};
 	const char * const evlist_usage[] = {

tools/perf/util/evsel.h

@@ -335,6 +335,7 @@ struct perf_attr_details {
 	bool freq;
 	bool verbose;
 	bool event_group;
+	bool force;
 };
 
 int perf_evsel__fprintf(struct perf_evsel *evsel,