dd6dda27a8
Add tracefs_configured() to return true if tracefs is configured in the kernel (succeeds to find tracefs), and debugfs_configured() if debugfs is configured in the kernel (succeeds to find debugfs). 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/20150202193553.190606690@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <stdbool.h>
|
|
#include <sys/vfs.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/mount.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#include "tracefs.h"
|
|
|
|
#ifndef TRACEFS_DEFAULT_PATH
|
|
#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
|
|
#endif
|
|
|
|
char tracefs_mountpoint[PATH_MAX + 1] = TRACEFS_DEFAULT_PATH;
|
|
|
|
static const char * const tracefs_known_mountpoints[] = {
|
|
TRACEFS_DEFAULT_PATH,
|
|
"/sys/kernel/debug/tracing",
|
|
"/tracing",
|
|
"/trace",
|
|
0,
|
|
};
|
|
|
|
static bool tracefs_found;
|
|
|
|
bool tracefs_configured(void)
|
|
{
|
|
return tracefs_find_mountpoint() != NULL;
|
|
}
|
|
|
|
/* find the path to the mounted tracefs */
|
|
const char *tracefs_find_mountpoint(void)
|
|
{
|
|
const char *ret;
|
|
|
|
if (tracefs_found)
|
|
return (const char *)tracefs_mountpoint;
|
|
|
|
ret = find_mountpoint("tracefs", (long) TRACEFS_MAGIC,
|
|
tracefs_mountpoint, PATH_MAX + 1,
|
|
tracefs_known_mountpoints);
|
|
|
|
if (ret)
|
|
tracefs_found = true;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* mount the tracefs somewhere if it's not mounted */
|
|
char *tracefs_mount(const char *mountpoint)
|
|
{
|
|
/* see if it's already mounted */
|
|
if (tracefs_find_mountpoint())
|
|
goto out;
|
|
|
|
/* if not mounted and no argument */
|
|
if (mountpoint == NULL) {
|
|
/* see if environment variable set */
|
|
mountpoint = getenv(PERF_TRACEFS_ENVIRONMENT);
|
|
/* if no environment variable, use default */
|
|
if (mountpoint == NULL)
|
|
mountpoint = TRACEFS_DEFAULT_PATH;
|
|
}
|
|
|
|
if (mount(NULL, mountpoint, "tracefs", 0, NULL) < 0)
|
|
return NULL;
|
|
|
|
/* save the mountpoint */
|
|
tracefs_found = true;
|
|
strncpy(tracefs_mountpoint, mountpoint, sizeof(tracefs_mountpoint));
|
|
out:
|
|
return tracefs_mountpoint;
|
|
}
|