minix/lib/libvtreefs/link.c

   1 /* VTreeFS - link.c - support for symbolic links and device nodes */
   2
   3 #include "inc.h"
   4
   5 /*
   6  * Retrieve a symbolic link target.
   7  */
   8 ssize_t
   9 fs_rdlink(ino_t ino_nr, struct fsdriver_data * data, size_t bytes)
  10 {
  11         char path[PATH_MAX];
  12         struct inode *node;
  13         size_t len;
  14         int r;
  15
  16         if ((node = find_inode(ino_nr)) == NULL)
  17                 return EINVAL;
  18
  19         /* The hook should be provided for any FS that adds symlink inodes.. */
  20         if (vtreefs_hooks->rdlink_hook == NULL)
  21                 return ENOSYS;
  22
  23         assert(!is_inode_deleted(node));        /* symlinks cannot be opened */
  24
  25         r = vtreefs_hooks->rdlink_hook(node, path, sizeof(path),
  26             get_inode_cbdata(node));
  27         if (r != OK) return r;
  28
  29         len = strlen(path);
  30         assert(len > 0 && len < sizeof(path));
  31
  32         if (len > bytes)
  33                 len = bytes;
  34
  35         /* Copy out the result. */
  36         if ((r = fsdriver_copyout(data, 0, path, len)) != OK)
  37                 return r;
  38
  39         return len;
  40 }
  41
  42 /*
  43  * Create a symbolic link.
  44  */
  45 int
  46 fs_slink(ino_t dir_nr, char * name, uid_t uid, gid_t gid,
  47         struct fsdriver_data * data, size_t bytes)
  48 {
  49         char path[PATH_MAX];
  50         struct inode *node;
  51         struct inode_stat istat;
  52         int r;
  53
  54         if ((node = find_inode(dir_nr)) == NULL)
  55                 return EINVAL;
  56
  57         if (vtreefs_hooks->slink_hook == NULL)
  58                 return ENOSYS;
  59
  60         if (get_inode_by_name(node, name) != NULL)
  61                 return EEXIST;
  62
  63         if (bytes >= sizeof(path))
  64                 return ENAMETOOLONG;
  65
  66         if ((r = fsdriver_copyin(data, 0, path, bytes)) != OK)
  67                 return r;
  68         path[bytes] = 0;
  69
  70         memset(&istat, 0, sizeof(istat));
  71         istat.mode = S_IFLNK | RWX_MODES;
  72         istat.uid = uid;
  73         istat.gid = gid;
  74         istat.size = strlen(path);
  75         istat.dev = 0;
  76
  77         return vtreefs_hooks->slink_hook(node, name, &istat, path,
  78             get_inode_cbdata(node));
  79 }
  80
  81 /*
  82  * Create a device node.
  83  */
  84 int
  85 fs_mknod(ino_t dir_nr, char * name, mode_t mode, uid_t uid, gid_t gid,
  86         dev_t rdev)
  87 {
  88         struct inode *node;
  89         struct inode_stat istat;
  90
  91         if ((node = find_inode(dir_nr)) == NULL)
  92                 return EINVAL;
  93
  94         if (get_inode_by_name(node, name) != NULL)
  95                 return EEXIST;
  96
  97         if (vtreefs_hooks->mknod_hook == NULL)
  98                 return ENOSYS;
  99
 100         memset(&istat, 0, sizeof(istat));
 101         istat.mode = mode;
 102         istat.uid = uid;
 103         istat.gid = gid;
 104         istat.size = 0;
 105         istat.dev = rdev;
 106
 107         return vtreefs_hooks->mknod_hook(node, name, &istat,
 108             get_inode_cbdata(node));
 109 }
 110
 111 /*
 112  * Unlink a node.
 113  */
 114 int
 115 fs_unlink(ino_t dir_nr, char * name, int __unused call)
 116 {
 117         struct inode *dir_node, *node;
 118
 119         if ((dir_node = find_inode(dir_nr)) == NULL)
 120                 return EINVAL;
 121
 122         if ((node = get_inode_by_name(dir_node, name)) == NULL)
 123                 return ENOENT;
 124
 125         if (vtreefs_hooks->unlink_hook == NULL)
 126                 return ENOSYS;
 127
 128         return vtreefs_hooks->unlink_hook(node, get_inode_cbdata(node));
 129 }