linux/tools/perf/util/sysfs.c

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#include "util.h"
#include "sysfs.h"
static const char * const sysfs_known_mountpoints[] = {
"/sys",
0,
};
static int sysfs_found;
char sysfs_mountpoint[PATH_MAX + 1];
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;
}