[PATCH 02/27] 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-thread
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       | 67 ++++++++++++++++++++++++++++++++++++--
 tools/perf/util/thread_map.h       | 12 +++++++
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/python-ext-sources b/tools/perf/util/python-ext-sources
index 5925fec90562..e23ded40c79e 100644
--- a/tools/perf/util/python-ext-sources
+++ b/tools/perf/util/python-ext-sources
@@ -20,3 +20,4 @@ util/stat.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 7a4be3754d05..5b2f2495af26 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 +31,51 @@ 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) {
+		/*
+		 * We're reading 16 bytes, while filename__read_str
+		 * allocates data per BUFSIZ bytes, so we can safely
+		 * mark the end of the string.
+		 */
+		(*comm)[size] = 0;
+		rtrim(*comm);
+	}
+
+	free(path);
+	return err;
+}
+
+static void comm_init(struct thread_map *map, int i)
+{
+	pid_t pid = thread_map__pid(map, i);
+	char *comm = NULL;
+
+	/* dummy pid comm initialization */
+	if (pid == -1) {
+		thread_map__set_comm(map, i, strdup("dummy"));
+		return;
+	}
+
+	/*
+	 * The comm name is like extra bonus ;-),
+	 * so just warn if we fail for any reason.
+	 */
+	if (get_comm(&comm, pid))
+		pr_warning("Couldn't resolve comm name for pid %d\n", pid);
+
+	thread_map__set_comm(map, i, comm);
+}
+
 struct thread_map *thread_map__new_by_pid(pid_t pid)
 {
 	struct thread_map *threads;
@@ -44,8 +91,10 @@ 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__set_pid(threads, i, atoi(namelist[i]->d_name));
+			comm_init(threads, i);
+		}
 		threads->nr = items;
 	}
 
@@ -63,6 +112,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
 	if (threads != NULL) {
 		thread_map__set_pid(threads, 0, tid);
 		threads->nr = 1;
+		comm_init(threads, 0);
 	}
 
 	return threads;
@@ -126,6 +176,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
 		for (i = 0; i < items; i++) {
 			thread_map__set_pid(threads, threads->nr + i,
 					    atoi(namelist[i]->d_name));
+			comm_init(threads, threads->nr + i);
 		}
 
 		for (i = 0; i < items; i++)
@@ -202,8 +253,9 @@ static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
 
 		threads = nt;
 
-		for (i = 0; i < items; i++) {
-			thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
+		for (i = 0; i < items; i++, j++) {
+			thread_map__set_pid(threads, j, atoi(namelist[i]->d_name));
+			comm_init(threads, j);
 			zfree(&namelist[i]);
 		}
 		threads->nr = total_tasks;
@@ -231,6 +283,7 @@ struct thread_map *thread_map__new_dummy(void)
 	if (threads != NULL) {
 		thread_map__set_pid(threads, 0, -1);
 		threads->nr = 1;
+		comm_init(threads, 0);
 	}
 	return threads;
 }
@@ -271,6 +324,7 @@ static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
 		threads = nt;
 		thread_map__set_pid(threads, ntasks - 1, tid);
 		threads->nr = ntasks;
+		comm_init(threads, ntasks - 1);
 	}
 out:
 	return threads;
@@ -294,6 +348,13 @@ 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 b9f40679f589..0f67843475e6 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 {
@@ -41,4 +42,15 @@ thread_map__set_pid(struct thread_map *map, int thread, pid_t pid)
 {
 	map->map[thread].pid = pid;
 }
+
+static inline char *thread_map__comm(struct thread_map *map, int thread)
+{
+	return map->map[thread].comm;
+}
+
+static inline void
+thread_map__set_comm(struct thread_map *map, int thread, char *comm)
+{
+	map->map[thread].comm = comm;
+}
 #endif	/* __PERF_THREAD_MAP_H */
-- 
1.9.3

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