perf trace/scripting: Add 'record' and 'report' options

Allow scripts to be recorded/executed by simply specifying the
script root name (the script name minus extension) along with
'record' or 'report' to 'perf trace'.

The script names shown by 'perf trace -l' can be directly used
to run the command-line contained within the corresponding
'-record' and '-report' versions of scripts in the scripts/*/bin
directories.

For example, to record the trace data needed to run the
wakeup-latency.pl script, the user can easily find the name of
the corresponding script from the script list and invoke it
using 'perf trace record', without having to remember the
details of how to do the same thing using the lower-level perf
trace command-line options:

root@tropicana:~# perf trace -l
List of available trace scripts:
  workqueue-stats                      workqueue stats (ins/exe/create/destroy)
  wakeup-latency                       system-wide min/max/avg wakeup latency
  rw-by-file <comm>                    r/w activity for a program, by file
  check-perf-trace                     useless but exhaustive test script
  rw-by-pid                            system-wide r/w activity

root@tropicana:~# perf trace record wakeup-latency
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.296 MB perf.data (~12931
samples) ]

To run the wakeup-latency.pl script using the captured data,
change 'record' to 'report' in the command-line:

root@tropicana:~# perf trace report wakeup-latency

wakeup_latency stats:

total_wakeups: 65
avg_wakeup_latency (ns): 22417
min_wakeup_latency (ns): 3470
max_wakeup_latency (ns): 223311

perf trace Perl script stopped

If the script takes options, thay can be simply added to the end
of the 'report' invocation:

root@tropicana:~# perf trace record rw-by-file
^C[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 0.782 MB perf.data (~34171
samples) ]

root@tropicana:~# perf trace report rw-by-file perf

file read counts for perf:

    fd     # reads  bytes_requested
------  ----------  -----------
   122        1934     1980416
   120           1          32

file write counts for perf:

    fd    # writes  bytes_written
------  ----------  -----------
     3        4006      280568

perf trace Perl script stopped

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
LKML-Reference: <1260867220-15699-6-git-send-email-tzanussi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-trace.c

@@ -469,6 +469,49 @@ static int list_available_scripts(const struct option *opt __used,
 	exit(0);
 }
 
+static char *get_script_path(const char *script_root, const char *suffix)
+{
+	struct dirent *script_next, *lang_next, script_dirent, lang_dirent;
+	char scripts_path[MAXPATHLEN];
+	char script_path[MAXPATHLEN];
+	DIR *scripts_dir, *lang_dir;
+	char lang_path[MAXPATHLEN];
+	char *str, *__script_root;
+	char *path = NULL;
+
+	snprintf(scripts_path, MAXPATHLEN, "%s/scripts", perf_exec_path());
+
+	scripts_dir = opendir(scripts_path);
+	if (!scripts_dir)
+		return NULL;
+
+	for_each_lang(scripts_dir, lang_dirent, lang_next) {
+		snprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
+			 lang_dirent.d_name);
+		lang_dir = opendir(lang_path);
+		if (!lang_dir)
+			continue;
+
+		for_each_script(lang_dir, script_dirent, script_next) {
+			__script_root = strdup(script_dirent.d_name);
+			str = ends_with(__script_root, suffix);
+			if (str) {
+				*str = '\0';
+				if (strcmp(__script_root, script_root))
+					continue;
+				snprintf(script_path, MAXPATHLEN, "%s/%s",
+					 lang_path, script_dirent.d_name);
+				path = strdup(script_path);
+				free(__script_root);
+				break;
+			}
+			free(__script_root);
+		}
+	}
+
+	return path;
+}
+
 static const char * const annotate_usage[] = {
 	"perf trace [<options>] <command>",
 	NULL
@@ -494,8 +537,47 @@ static const struct option options[] = {
 
 int cmd_trace(int argc, const char **argv, const char *prefix __used)
 {
-	int err;
 	struct perf_session *session;
+	const char *suffix = NULL;
+	const char **__argv;
+	char *script_path;
+	int i, err;
+
+	if (argc >= 2 && strncmp(argv[1], "rec", strlen("rec")) == 0) {
+		if (argc < 3) {
+			fprintf(stderr,
+				"Please specify a record script\n");
+			return -1;
+		}
+		suffix = RECORD_SUFFIX;
+	}
+
+	if (argc >= 2 && strncmp(argv[1], "rep", strlen("rep")) == 0) {
+		if (argc < 3) {
+			fprintf(stderr,
+				"Please specify a report script\n");
+			return -1;
+		}
+		suffix = REPORT_SUFFIX;
+	}
+
+	if (suffix) {
+		script_path = get_script_path(argv[2], suffix);
+		if (!script_path) {
+			fprintf(stderr, "script not found\n");
+			return -1;
+		}
+
+		__argv = malloc((argc + 1) * sizeof(const char *));
+		__argv[0] = "/bin/sh";
+		__argv[1] = script_path;
+		for (i = 3; i < argc; i++)
+			__argv[i - 1] = argv[i];
+		__argv[argc - 1] = NULL;
+
+		execvp("/bin/sh", (char **)__argv);
+		exit(-1);
+	}
 
 	symbol__init(0);