Allow the script generated by "perf script -g <language>" to be a file
path and the language determined by the file extension. This is useful
in testing so that the generated script file can be written to a test
directory.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/Documentation/perf-script.txt |  6 ++++--
 tools/perf/builtin-script.c              | 24 ++++++++++++++++++++----
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index 03d112960632..ddf92f9c7821 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -98,8 +98,10 @@ OPTIONS
 
 -g::
 --gen-script=::
-        Generate perf-script.[ext] starter script for given language,
-        using current perf.data.
+	Generate a starter script. If a language is given then the
+        script is named perf-script.[ext] according to the
+        language. If a file path is given then python is used for
+        files ending '.py' and perl used for files ending '.pl'.
 
 --dlfilter=<file>::
 	Filter sample events using the given shared object file.
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 14c6f6c3c4f2..7c743a303507 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4489,6 +4489,7 @@ int cmd_script(int argc, const char **argv)
 	if (generate_script_lang) {
 		struct stat perf_stat;
 		int input;
+		char *filename = strdup("perf-script");
 
 		if (output_set_by_user()) {
 			fprintf(stderr,
@@ -4516,17 +4517,32 @@ int cmd_script(int argc, const char **argv)
 		}
 
 		scripting_ops = script_spec__lookup(generate_script_lang);
+		if (!scripting_ops && ends_with(generate_script_lang, ".py")) {
+			scripting_ops = script_spec__lookup("python");
+			free(filename);
+			filename = strdup(generate_script_lang);
+			filename[strlen(filename) - 3] = '\0';
+		} else if (!scripting_ops && ends_with(generate_script_lang, ".pl")) {
+			scripting_ops = script_spec__lookup("perl");
+			free(filename);
+			filename = strdup(generate_script_lang);
+			filename[strlen(filename) - 3] = '\0';
+		}
 		if (!scripting_ops) {
-			fprintf(stderr, "invalid language specifier");
+			fprintf(stderr, "invalid language specifier '%s'\n", generate_script_lang);
 			err = -ENOENT;
 			goto out_delete;
 		}
+		if (!filename) {
+			err = -ENOMEM;
+			goto out_delete;
+		}
 #ifdef HAVE_LIBTRACEEVENT
-		err = scripting_ops->generate_script(session->tevent.pevent,
-						     "perf-script");
+		err = scripting_ops->generate_script(session->tevent.pevent, filename);
 #else
-		err = scripting_ops->generate_script(NULL, "perf-script");
+		err = scripting_ops->generate_script(NULL, filename);
 #endif
+		free(filename);
 		goto out_delete;
 	}
 
-- 
2.53.0.rc2.204.g2597b5adb4-goog