[PATCH 04/30] perf tools: Add comm string into struct thread_map

[Jiri Olsa <jolsa@kernel.org>]

Adding support to hold comm name together with pids in
'struct thread_map'. It will be useful for --per-task
option to display task pid together with task name.

Getting the task name from /proc/$pid/comm.

Link: http://lkml.kernel.org/n/tip-pf6bgmbujukce0sgliuhj2f4@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/python-ext-sources |  1 +
 tools/perf/util/thread_map.c       | 63 +++++++++++++++++++++++++++++++++++---
 tools/perf/util/thread_map.h       |  2 ++
 3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/python-ext-sources b/tools/perf/util/python-ext-sources
index 4d28624a1eca..55ba8968a263 100644
--- a/tools/perf/util/python-ext-sources
+++ b/tools/perf/util/python-ext-sources
@@ -19,3 +19,4 @@ util/rblist.c
 util/strlist.c
 util/trace-event.c
 ../../lib/rbtree.c
+util/string.c
diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index 7f03f9facfdd..f7a49a693d27 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -8,8 +8,10 @@
 #include <unistd.h>
 #include "strlist.h"
 #include <string.h>
+#include <api/fs/fs.h>
 #include "thread_map.h"
 #include "util.h"
+#include "debug.h"
 
 /* Skip "." and ".." directories */
 static int filter(const struct dirent *dir)
@@ -29,6 +31,44 @@ static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
 
 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
 
+static int get_comm(char **comm, pid_t pid)
+{
+	char *path;
+	size_t size;
+	int err;
+
+	if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
+		return -ENOMEM;
+
+	err = filename__read_str(path, comm, &size);
+	if (!err)
+		rtrim(*comm);
+
+	free(path);
+	return err;
+}
+
+static void comm_init(struct thread_map *map, int i)
+{
+	struct thread_map_data *data = &map->map[i];
+
+	/*
+	 * The comm name is like extra bonus ;-),
+	 * so just warn if we fail for any reason.
+	 */
+	data->comm = NULL;
+
+	/* dummy pid comm initialization */
+	if (data->pid == -1) {
+		data->comm = strdup("dummy");
+		return;
+	}
+
+	/* try to get pid's comm string */
+	if (get_comm(&data->comm, data->pid))
+		pr_warning("Couldn't resolve comm name for pid %d\n", data->pid);
+}
+
 struct thread_map *thread_map__new_by_pid(pid_t pid)
 {
 	struct thread_map *threads;
@@ -44,8 +84,10 @@ struct thread_map *thread_map__new_by_pid(pid_t pid)
 
 	threads = thread_map__alloc(items);
 	if (threads != NULL) {
-		for (i = 0; i < items; i++)
+		for (i = 0; i < items; i++) {
 			thread_map__pid(threads, i) = atoi(namelist[i]->d_name);
+			comm_init(threads, i);
+		}
 		threads->nr = items;
 	}
 
@@ -63,6 +105,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
 	if (threads != NULL) {
 		thread_map__pid(threads, 0) = tid;
 		threads->nr		    = 1;
+		comm_init(threads, 0);
 	}
 
 	return threads;
@@ -123,8 +166,10 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
 			threads = tmp;
 		}
 
-		for (i = 0; i < items; i++)
+		for (i = 0; i < items; i++) {
 			thread_map__pid(threads, threads->nr + i) = atoi(namelist[i]->d_name);
+			comm_init(threads, threads->nr + i);
+		}
 
 		for (i = 0; i < items; i++)
 			zfree(&namelist[i]);
@@ -200,8 +245,9 @@ static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
 
 		threads = nt;
 
-		for (i = 0; i < items; i++) {
-			thread_map__pid(threads, j++) = atoi(namelist[i]->d_name);
+		for (i = 0; i < items; i++, j++) {
+			thread_map__pid(threads, j) = atoi(namelist[i]->d_name);
+			comm_init(threads, j);
 			zfree(&namelist[i]);
 		}
 		threads->nr = total_tasks;
@@ -229,6 +275,7 @@ struct thread_map *thread_map__new_dummy(void)
 	if (threads != NULL) {
 		thread_map__pid(threads, 0) = -1;
 		threads->nr		    = 1;
+		comm_init(threads, 0);
 	}
 	return threads;
 }
@@ -269,6 +316,7 @@ static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
 		threads = nt;
 		thread_map__pid(threads, ntasks - 1) = tid;
 		threads->nr			     = ntasks;
+		comm_init(threads, ntasks - 1);
 	}
 out:
 	return threads;
@@ -292,6 +340,13 @@ struct thread_map *thread_map__new_str(const char *pid, const char *tid,
 
 void thread_map__delete(struct thread_map *threads)
 {
+	int i;
+
+	if (threads) {
+		for (i = 0; i < threads->nr; i++)
+			free(thread_map__comm(threads, i));
+	}
+
 	free(threads);
 }
 
diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
index 9377850c7b71..6933f9d316d9 100644
--- a/tools/perf/util/thread_map.h
+++ b/tools/perf/util/thread_map.h
@@ -6,6 +6,7 @@
 
 struct thread_map_data {
 	pid_t    pid;
+	char	*comm;
 };
 
 struct thread_map {
@@ -14,6 +15,7 @@ struct thread_map {
 };
 
 #define thread_map__pid(__m, __t)  __m->map[__t].pid
+#define thread_map__comm(__m, __t) __m->map[__t].comm
 
 struct thread_map *thread_map__new_dummy(void);
 struct thread_map *thread_map__new_by_pid(pid_t pid);
-- 
1.9.3