perf tools: Add sysfs mountpoint interface
Adding sysfs object to provide sysfs mount information in the same way
as debugfs object does.
The object provides following function:
sysfs_find_mountpoint
which returns the sysfs mount mount.
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1327674868-10486-4-git-send-email-jolsa@redhat.com
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/sysfs.c b/tools/perf/util/sysfs.c
new file mode 100644
index 0000000..48c6902
--- /dev/null
+++ b/tools/perf/util/sysfs.c
@@ -0,0 +1,60 @@
+
+#include "util.h"
+#include "sysfs.h"
+
+static const char * const sysfs_known_mountpoints[] = {
+ "/sys",
+ 0,
+};
+
+static int sysfs_found;
+char sysfs_mountpoint[PATH_MAX];
+
+static int sysfs_valid_mountpoint(const char *sysfs)
+{
+ struct statfs st_fs;
+
+ if (statfs(sysfs, &st_fs) < 0)
+ return -ENOENT;
+ else if (st_fs.f_type != (long) SYSFS_MAGIC)
+ return -ENOENT;
+
+ return 0;
+}
+
+const char *sysfs_find_mountpoint(void)
+{
+ const char * const *ptr;
+ char type[100];
+ FILE *fp;
+
+ if (sysfs_found)
+ return (const char *) sysfs_mountpoint;
+
+ ptr = sysfs_known_mountpoints;
+ while (*ptr) {
+ if (sysfs_valid_mountpoint(*ptr) == 0) {
+ sysfs_found = 1;
+ strcpy(sysfs_mountpoint, *ptr);
+ return sysfs_mountpoint;
+ }
+ ptr++;
+ }
+
+ /* give up and parse /proc/mounts */
+ fp = fopen("/proc/mounts", "r");
+ if (fp == NULL)
+ return NULL;
+
+ while (!sysfs_found &&
+ fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
+ sysfs_mountpoint, type) == 2) {
+
+ if (strcmp(type, "sysfs") == 0)
+ sysfs_found = 1;
+ }
+
+ fclose(fp);
+
+ return sysfs_found ? sysfs_mountpoint : NULL;
+}