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tools lib fs: Add helper to find mounted file systems

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In preparation for adding tracefs for perf to use, create a findfs
helper utility that find_debugfs uses instead of hard coding the search
in the code. This will allow for a find_tracefs to be used as well.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150202193552.735023362@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Steven Rostedt (Red Hat)
2015-02-02 14:35:03 -05:00
committed by Arnaldo Carvalho de Melo
parent 5693c92660
commit cde164aee9
5 changed files with 94 additions and 54 deletions
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51
tools/lib/api/fs/debugfs.c
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@@ -20,58 +20,21 @@ static const char * const debugfs_known_mountpoints[] = {
static bool debugfs_found;
/* verify that a mountpoint is actually a debugfs instance */
static int debugfs_valid_mountpoint(const char *debugfs)
{
struct statfs st_fs;
if (statfs(debugfs, &st_fs) < 0)
return -ENOENT;
else if ((long)st_fs.f_type != (long)DEBUGFS_MAGIC)
return -ENOENT;
return 0;
}
/* find the path to the mounted debugfs */
const char *debugfs_find_mountpoint(void)
{
const char * const *ptr;
char type[100];
FILE *fp;
const char *ret;
if (debugfs_found)
return (const char *)debugfs_mountpoint;
ptr = debugfs_known_mountpoints;
while (*ptr) {
if (debugfs_valid_mountpoint(*ptr) == 0) {
debugfs_found = true;
strcpy(debugfs_mountpoint, *ptr);
return debugfs_mountpoint;
}
ptr++;
}
ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC,
debugfs_mountpoint, PATH_MAX + 1,
debugfs_known_mountpoints);
if (ret)
debugfs_found = true;
/* give up and parse /proc/mounts */
fp = fopen("/proc/mounts", "r");
if (fp == NULL)
return NULL;
while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
debugfs_mountpoint, type) == 2) {
if (strcmp(type, "debugfs") == 0)
break;
}
fclose(fp);
if (strcmp(type, "debugfs") != 0)
return NULL;
debugfs_found = true;
return debugfs_mountpoint;
return ret;
}
/* mount the debugfs somewhere if it's not mounted */