tools/perf/util/fs.c

   1
   2 /* TODO merge/factor into tools/lib/lk/debugfs.c */
   3
   4 #include "util.h"
   5 #include "util/fs.h"
   6
   7 static const char * const sysfs__fs_known_mountpoints[] = {
   8         "/sys",
   9         0,
  10 };
  11
  12 struct fs {
  13         const char              *name;
  14         const char * const      *mounts;
  15         char                     path[PATH_MAX + 1];
  16         bool                     found;
  17         long                     magic;
  18 };
  19
  20 enum {
  21         FS__SYSFS = 0,
  22 };
  23
  24 static struct fs fs__entries[] = {
  25         [FS__SYSFS] = {
  26                 .name   = "sysfs",
  27                 .mounts = sysfs__fs_known_mountpoints,
  28                 .magic  = SYSFS_MAGIC,
  29         },
  30 };
  31
  32 static bool fs__read_mounts(struct fs *fs)
  33 {
  34         bool found = false;
  35         char type[100];
  36         FILE *fp;
  37
  38         fp = fopen("/proc/mounts", "r");
  39         if (fp == NULL)
  40                 return NULL;
  41
  42         while (!found &&
  43                fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
  44                       fs->path, type) == 2) {
  45
  46                 if (strcmp(type, fs->name) == 0)
  47                         found = true;
  48         }
  49
  50         fclose(fp);
  51         return fs->found = found;
  52 }
  53
  54 static int fs__valid_mount(const char *fs, long magic)
  55 {
  56         struct statfs st_fs;
  57
  58         if (statfs(fs, &st_fs) < 0)
  59                 return -ENOENT;
  60         else if (st_fs.f_type != magic)
  61                 return -ENOENT;
  62
  63         return 0;
  64 }
  65
  66 static bool fs__check_mounts(struct fs *fs)
  67 {
  68         const char * const *ptr;
  69
  70         ptr = fs->mounts;
  71         while (*ptr) {
  72                 if (fs__valid_mount(*ptr, fs->magic) == 0) {
  73                         fs->found = true;
  74                         strcpy(fs->path, *ptr);
  75                         return true;
  76                 }
  77                 ptr++;
  78         }
  79
  80         return false;
  81 }
  82
  83 static const char *fs__get_mountpoint(struct fs *fs)
  84 {
  85         if (fs__check_mounts(fs))
  86                 return fs->path;
  87
  88         return fs__read_mounts(fs) ? fs->path : NULL;
  89 }
  90
  91 static const char *fs__find_mountpoint(int idx)
  92 {
  93         struct fs *fs = &fs__entries[idx];
  94
  95         if (fs->found)
  96                 return (const char *)fs->path;
  97
  98         return fs__get_mountpoint(fs);
  99 }
 100
 101 #define FIND_MOUNTPOINT(name, idx)              \
 102 const char *name##_find_mountpoint(void)        \
 103 {                                               \
 104         return fs__find_mountpoint(idx);        \
 105 }
 106
 107 FIND_MOUNTPOINT(sysfs, FS__SYSFS);