perf data: Support using -f to override perf.data file ownership for 'convert'

Enable perf data convert 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 17:35 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

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

  usage: perf data convert [<options>]

     -v, --verbose         be more verbose
     -i, --input <file>    input file name
         --to-ctf ...      Convert to CTF format

After this patch:

 # perf data convert --to-ctf=./ctf-data/
 File perf.data not owned by current user or root (use -f to override)
 # perf data convert --to-ctf=./ctf-data/ -f
 # ls ctf-data/
 metadata  perf_stream_0

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

Signed-off-by: Yunlong Song <yunlong.song@huawei.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/1427982439-27388-11-git-send-email-yunlong.song@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-data.c

@@ -53,12 +53,14 @@ static int cmd_data_convert(int argc, const char **argv,
 			    const char *prefix __maybe_unused)
 {
 	const char *to_ctf     = NULL;
+	bool force = false;
 	const struct option options[] = {
 		OPT_INCR('v', "verbose", &verbose, "be more verbose"),
 		OPT_STRING('i', "input", &input_name, "file", "input file name"),
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
 		OPT_STRING(0, "to-ctf", &to_ctf, NULL, "Convert to CTF format"),
 #endif
+		OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
 		OPT_END()
 	};
 
@@ -76,7 +78,7 @@ static int cmd_data_convert(int argc, const char **argv,
 
 	if (to_ctf) {
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
-		return bt_convert__perf2ctf(input_name, to_ctf);
+		return bt_convert__perf2ctf(input_name, to_ctf, force);
 #else
 		pr_err("The libbabeltrace support is not compiled in.\n");
 		return -1;

tools/perf/util/data-convert-bt.c

@@ -791,12 +791,13 @@ err:
 	return -1;
 }
 
-int bt_convert__perf2ctf(const char *input, const char *path)
+int bt_convert__perf2ctf(const char *input, const char *path, bool force)
 {
 	struct perf_session *session;
 	struct perf_data_file file = {
 		.path = input,
 		.mode = PERF_DATA_MODE_READ,
+		.force = force,
 	};
 	struct convert c = {
 		.tool = {

tools/perf/util/data-convert-bt.h

@@ -2,7 +2,7 @@
 #define __DATA_CONVERT_BT_H
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
 
-int bt_convert__perf2ctf(const char *input_name, const char *to_ctf);
+int bt_convert__perf2ctf(const char *input_name, const char *to_ctf, bool force);
 
 #endif /* HAVE_LIBBABELTRACE_SUPPORT */
 #endif /* __DATA_CONVERT_BT_H */