101 lines
2.1 KiB
C
101 lines
2.1 KiB
C
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <stdbool.h>
|
|
#include <sys/vfs.h>
|
|
#include <sys/mount.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#include "debugfs.h"
|
|
|
|
char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
|
|
|
|
static const char * const debugfs_known_mountpoints[] = {
|
|
"/sys/kernel/debug",
|
|
"/debug",
|
|
0,
|
|
};
|
|
|
|
static bool debugfs_found;
|
|
|
|
/* find the path to the mounted debugfs */
|
|
const char *debugfs_find_mountpoint(void)
|
|
{
|
|
const char * const *ptr;
|
|
char type[100];
|
|
FILE *fp;
|
|
|
|
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++;
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
/* verify that a mountpoint is actually a debugfs instance */
|
|
|
|
int debugfs_valid_mountpoint(const char *debugfs)
|
|
{
|
|
struct statfs st_fs;
|
|
|
|
if (statfs(debugfs, &st_fs) < 0)
|
|
return -ENOENT;
|
|
else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
|
|
return -ENOENT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* 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 = "/sys/kernel/debug";
|
|
}
|
|
|
|
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;
|
|
}
|