fs/adfs/namei.c

   1 /*
   2  *  linux/fs/adfs/namei.c
   3  *
   4  * Copyright (C) 1997 Russell King
   5  */
   6
   7 #include <linux/errno.h>
   8 #include <linux/fs.h>
   9 #include <linux/adfs_fs.h>
  10 #include <linux/fcntl.h>
  11 #include <linux/sched.h>
  12 #include <linux/stat.h>
  13 #include <linux/string.h>
  14 #include <linux/locks.h>
  15
  16 /*
  17  * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure
  18  */
  19 static int adfs_match (int len, const char * const name, struct adfs_idir_entry *de)
  20 {
  21         int i;
  22
  23         if (!de || len > ADFS_NAME_LEN)
  24                 return 0;
  25         /*
  26          * "" means "." ---> so paths like "/usr/lib//libc.a" work
  27          */
  28         if (!len && de->name_len == 1 && de->name[0] == '.' &&
  29             de->name[1] == '\0')
  30                 return 1;
  31         if (len != de->name_len)
  32                 return 0;
  33
  34         for (i = 0; i < len; i++)
  35                 if ((de->name[i] ^ name[i]) & 0x5f)
  36                         return 0;
  37         return 1;
  38 }
  39
  40 static int adfs_find_entry (struct inode *dir, const char * const name, int namelen,
  41                             struct adfs_idir_entry *ide)
  42 {
  43         struct super_block *sb;
  44         struct buffer_head *bh[4];
  45         union  adfs_dirtail dt;
  46         unsigned long parent_object_id, dir_object_id;
  47         int buffers, pos;
  48
  49         sb = dir->i_sb;
  50
  51         if (adfs_inode_validate (dir)) {
  52                 adfs_error (sb, "adfs_find_entry",
  53                             "invalid inode number: %lu", dir->i_ino);
  54                 return 0;
  55         }
  56
  57         if (!(buffers = adfs_dir_read (dir, bh))) {
  58                 adfs_error (sb, "adfs_find_entry", "unable to read directory");
  59                 return 0;
  60         }
  61
  62         if (adfs_dir_check (dir, bh, buffers, &dt)) {
  63                 adfs_dir_free (bh, buffers);
  64                 return 0;
  65         }
  66
  67         parent_object_id = adfs_val (dt.new.dirparent, 3);
  68         dir_object_id = adfs_inode_objid (dir);
  69
  70         if (namelen == 2 && name[0] == '.' && name[1] == '.') {
  71                 ide->name_len = 2;
  72                 ide->name[0] = ide->name[1] = '.';
  73                 ide->name[2] = '\0';
  74                 ide->inode_no = adfs_inode_generate (parent_object_id, 0);
  75                 adfs_dir_free (bh, buffers);
  76                 return 1;
  77         }
  78
  79         pos = 5;
  80
  81         do {
  82                 if (!adfs_dir_get (sb, bh, buffers, pos, dir_object_id, ide))
  83                         break;
  84
  85                 if (adfs_match (namelen, name, ide)) {
  86                         adfs_dir_free (bh, buffers);
  87                         return pos;
  88                 }
  89                 pos += 26;
  90         } while (1);
  91         adfs_dir_free (bh, buffers);
  92         return 0;
  93 }
  94
  95 struct dentry *adfs_lookup (struct inode *dir, struct dentry *dentry)
  96 {
  97         struct inode *inode = NULL;
  98         struct adfs_idir_entry de;
  99         unsigned long ino;
 100
 101         if (dentry->d_name.len > ADFS_NAME_LEN)
 102                 return ERR_PTR(-ENAMETOOLONG);
 103
 104         if (adfs_find_entry (dir, dentry->d_name.name, dentry->d_name.len, &de)) {
 105                 ino = de.inode_no;
 106                 inode = iget (dir->i_sb, ino);
 107
 108                 if (!inode)
 109                         return ERR_PTR(-EACCES);
 110         }
 111         d_add(dentry, inode);
 112         return NULL;
 113 }