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>
118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
#define _GNU_SOURCE
|
|
#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 "debugfs.h"
|
|
|
|
#ifndef DEBUGFS_DEFAULT_PATH
|
|
#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
|
|
#endif
|
|
|
|
char debugfs_mountpoint[PATH_MAX + 1] = DEBUGFS_DEFAULT_PATH;
|
|
|
|
static const char * const debugfs_known_mountpoints[] = {
|
|
DEBUGFS_DEFAULT_PATH,
|
|
"/debug",
|
|
0,
|
|
};
|
|
|
|
static bool debugfs_found;
|
|
|
|
bool debugfs_configured(void)
|
|
{
|
|
return debugfs_find_mountpoint() != NULL;
|
|
}
|
|
|
|
/* find the path to the mounted debugfs */
|
|
const char *debugfs_find_mountpoint(void)
|
|
{
|
|
const char *ret;
|
|
|
|
if (debugfs_found)
|
|
return (const char *)debugfs_mountpoint;
|
|
|
|
ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC,
|
|
debugfs_mountpoint, PATH_MAX + 1,
|
|
debugfs_known_mountpoints);
|
|
if (ret)
|
|
debugfs_found = true;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* mount the debugfs somewhere if it's not mounted */
|
|
char *debugfs_mount(const char *mountpoint)
|
|
{
|
|
/* see if it's already mounted */
|
|
if (debugfs_find_mountpoint())
|
|
goto out;
|
|
|
|
/* if not mounted and no argument */
|
|
if (mountpoint == NULL) {
|
|
/* see if environment variable set */
|
|
mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);
|
|
/* if no environment variable, use default */
|
|
if (mountpoint == NULL)
|
|
mountpoint = DEBUGFS_DEFAULT_PATH;
|
|
}
|
|
|
|
if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
|
|
return NULL;
|
|
|
|
/* save the mountpoint */
|
|
debugfs_found = true;
|
|
strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
|
|
out:
|
|
return debugfs_mountpoint;
|
|
}
|
|
|
|
int debugfs__strerror_open(int err, char *buf, size_t size, const char *filename)
|
|
{
|
|
char sbuf[128];
|
|
|
|
switch (err) {
|
|
case ENOENT:
|
|
if (debugfs_found) {
|
|
snprintf(buf, size,
|
|
"Error:\tFile %s/%s not found.\n"
|
|
"Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
|
|
debugfs_mountpoint, filename);
|
|
break;
|
|
}
|
|
snprintf(buf, size, "%s",
|
|
"Error:\tUnable to find debugfs\n"
|
|
"Hint:\tWas your kernel compiled with debugfs support?\n"
|
|
"Hint:\tIs the debugfs filesystem mounted?\n"
|
|
"Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
|
|
break;
|
|
case EACCES:
|
|
snprintf(buf, size,
|
|
"Error:\tNo permissions to read %s/%s\n"
|
|
"Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
|
|
debugfs_mountpoint, filename, debugfs_mountpoint);
|
|
break;
|
|
default:
|
|
snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int debugfs__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name)
|
|
{
|
|
char path[PATH_MAX];
|
|
|
|
snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*");
|
|
|
|
return debugfs__strerror_open(err, buf, size, path);
|
|
}
|