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 static const char * const procfs__known_mountpoints[] = {
  13         "/proc",
  14         0,
  15 };
  16
  17 struct fs {
  18         const char              *name;
  19         const char * const      *mounts;
  20         char                     path[PATH_MAX + 1];
  21         bool                     found;
  22         long                     magic;
  23 };
  24
  25 enum {
  26         FS__SYSFS  = 0,
  27         FS__PROCFS = 1,
  28 };
  29
  30 static struct fs fs__entries[] = {
  31         [FS__SYSFS] = {
  32                 .name   = "sysfs",
  33                 .mounts = sysfs__fs_known_mountpoints,
  34                 .magic  = SYSFS_MAGIC,
  35         },
  36         [FS__PROCFS] = {
  37                 .name   = "proc",
  38                 .mounts = procfs__known_mountpoints,
  39                 .magic  = PROC_SUPER_MAGIC,
  40         },
  41 };
  42
  43 static bool fs__read_mounts(struct fs *fs)
  44 {
  45         bool found = false;
  46         char type[100];
  47         FILE *fp;
  48
  49         fp = fopen("/proc/mounts", "r");
  50         if (fp == NULL)
  51                 return NULL;
  52
  53         while (!found &&
  54                fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
  55                       fs->path, type) == 2) {
  56
  57                 if (strcmp(type, fs->name) == 0)
  58                         found = true;
  59         }
  60
  61         fclose(fp);
  62         return fs->found = found;
  63 }
  64
  65 static int fs__valid_mount(const char *fs, long magic)
  66 {
  67         struct statfs st_fs;
  68
  69         if (statfs(fs, &st_fs) < 0)
  70                 return -ENOENT;
  71         else if (st_fs.f_type != magic)
  72                 return -ENOENT;
  73
  74         return 0;
  75 }
  76
  77 static bool fs__check_mounts(struct fs *fs)
  78 {
  79         const char * const *ptr;
  80
  81         ptr = fs->mounts;
  82         while (*ptr) {
  83                 if (fs__valid_mount(*ptr, fs->magic) == 0) {
  84                         fs->found = true;
  85                         strcpy(fs->path, *ptr);
  86                         return true;
  87                 }
  88                 ptr++;
  89         }
  90
  91         return false;
  92 }
  93
  94 static const char *fs__get_mountpoint(struct fs *fs)
  95 {
  96         if (fs__check_mounts(fs))
  97                 return fs->path;
  98
  99         return fs__read_mounts(fs) ? fs->path : NULL;
 100 }
 101
 102 static const char *fs__mountpoint(int idx)
 103 {
 104         struct fs *fs = &fs__entries[idx];
 105
 106         if (fs->found)
 107                 return (const char *)fs->path;
 108
 109         return fs__get_mountpoint(fs);
 110 }
 111
 112 #define FS__MOUNTPOINT(name, idx)       \
 113 const char *name##__mountpoint(void)    \
 114 {                                       \
 115         return fs__mountpoint(idx);     \
 116 }
 117
 118 FS__MOUNTPOINT(sysfs,  FS__SYSFS);
 119 FS__MOUNTPOINT(procfs, FS__PROCFS);