perf tools: Simplify debugfs mountpoint handling code
We don't need to have two PATH_MAX char sized arrays holding it, just
one in util/debugfs.c will do.
Also rename debugfs_path to tracing_events_path, as it is not the path
to debugfs, that is debugfs_mountpoint. Both are now accessible.
This will allow accessing this code in the perf python binding without
having to drag in perf.c and util/parse-events.c.
The defaults for these variables are the canonical "/sys/kernel/debug"
and "/sys/kernel/debug/tracing/events/", removing the need for simple
tools to call debugfs_mount(NULL).
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ug9jvtjrsqbluuhqqxpvg30f@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/debugfs.c b/tools/perf/util/debugfs.c
index 680be34..ffc35e7 100644
--- a/tools/perf/util/debugfs.c
+++ b/tools/perf/util/debugfs.c
@@ -2,10 +2,12 @@
#include "debugfs.h"
#include "cache.h"
+#include <linux/kernel.h>
#include <sys/mount.h>
static int debugfs_premounted;
-static char debugfs_mountpoint[PATH_MAX + 1];
+char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
+char tracing_events_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing/events";
static const char *debugfs_known_mountpoints[] = {
"/sys/kernel/debug/",
@@ -64,7 +66,7 @@
/* give up and parse /proc/mounts */
fp = fopen("/proc/mounts", "r");
if (fp == NULL)
- die("Can't open /proc/mounts for read");
+ return NULL;
while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
debugfs_mountpoint, type) == 2) {
@@ -106,6 +108,12 @@
return 0;
}
+static void debugfs_set_tracing_events_path(const char *mountpoint)
+{
+ snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s",
+ mountpoint, "tracing/events");
+}
+
/* mount the debugfs somewhere if it's not mounted */
char *debugfs_mount(const char *mountpoint)
@@ -113,7 +121,7 @@
/* see if it's already mounted */
if (debugfs_find_mountpoint()) {
debugfs_premounted = 1;
- return debugfs_mountpoint;
+ goto out;
}
/* if not mounted and no argument */
@@ -129,12 +137,19 @@
return NULL;
/* save the mountpoint */
- strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
debugfs_found = 1;
-
+ strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
+out:
+ debugfs_set_tracing_events_path(debugfs_mountpoint);
return debugfs_mountpoint;
}
+void debugfs_set_path(const char *mountpoint)
+{
+ snprintf(debugfs_mountpoint, sizeof(debugfs_mountpoint), "%s", mountpoint);
+ debugfs_set_tracing_events_path(mountpoint);
+}
+
/* umount the debugfs */
int debugfs_umount(void)