fs/qnx4/symlinks.c

   1 /*
   2  * QNX4 file system, Linux implementation.
   3  *
   4  * Version : 0.1
   5  *
   6  * Using parts of the xiafs filesystem.
   7  *
   8  * History :
   9  *
  10  * 28-05-1998 by Richard Frowijn : first release.
  11  * 21-06-1998 by Frank Denis : ugly changes to make it compile on Linux 2.1.99+
  12  */
  13
  14 /* THIS FILE HAS TO BE REWRITTEN */
  15
  16 #include <linux/errno.h>
  17 #include <linux/sched.h>
  18 #include <linux/fs.h>
  19 #include <linux/qnx4_fs.h>
  20 #include <linux/stat.h>
  21
  22 #include <asm/segment.h>
  23 #include <asm/uaccess.h>
  24
  25 static int qnx4_readlink(struct dentry *, char *, int);
  26 static struct dentry *qnx4_follow_link(struct dentry *, struct dentry *, unsigned int follow);
  27
  28 /*
  29  * symlinks can't do much...
  30  */
  31 struct inode_operations qnx4_symlink_inode_operations =
  32 {
  33         NULL,                   /* no file-operations */
  34         NULL,                   /* create */
  35         NULL,                   /* lookup */
  36         NULL,                   /* link */
  37         NULL,                   /* unlink */
  38         NULL,                   /* symlink */
  39         NULL,                   /* mkdir */
  40         NULL,                   /* rmdir */
  41         NULL,                   /* mknod */
  42         NULL,                   /* rename */
  43         qnx4_readlink,          /* readlink */
  44         qnx4_follow_link,       /* follow_link */
  45         NULL,                   /* readpage */
  46         NULL,                   /* writepage */
  47         NULL,                   /* bmap */
  48         NULL,                   /* truncate */
  49         NULL                    /* permission */
  50 };
  51
  52 static struct dentry *qnx4_follow_link(struct dentry *dentry,
  53                                        struct dentry *base, unsigned int follow)
  54 {
  55 #if 0
  56         struct inode *inode = dentry->d_inode;
  57         struct buffer_head *bh;
  58
  59         if (!inode) {
  60                 return ERR_PTR(-ENOENT);
  61         }
  62         if (current->link_count > 5) {
  63                 return ERR_PTR(-ELOOP);
  64         }
  65         if (!(bh = qnx4_bread(inode, 0, 0))) {
  66                 return ERR_PTR(-EIO);
  67         }
  68         current->link_count++;
  69         current->link_count--;
  70         brelse(bh);
  71         return 0;
  72 #else
  73         printk("qnx4: qnx4_follow_link needs to be fixed.\n");
  74         return ERR_PTR(-EIO);
  75 #endif
  76 }
  77
  78 static int qnx4_readlink(struct dentry *dentry, char *buffer, int buflen)
  79 {
  80         struct inode *inode = dentry->d_inode;
  81         struct buffer_head *bh;
  82         int i;
  83         char c;
  84         struct qnx4_inode_info *qnx4_ino;
  85
  86         QNX4DEBUG(("qnx4: qnx4_readlink() called\n"));
  87
  88         if (buffer == NULL || inode == NULL || !S_ISLNK(inode->i_mode)) {
  89                 return -EINVAL;
  90         }
  91         qnx4_ino = &inode->u.qnx4_i;
  92         if (buflen > 1023) {
  93                 buflen = 1023;
  94         }
  95         bh = bread(inode->i_dev, qnx4_ino->i_first_xtnt.xtnt_blk,
  96                    QNX4_BLOCK_SIZE);
  97         QNX4DEBUG(("qnx4: qnx4_bread sym called -> [%s]\n",
  98                    bh->b_data));
  99         if (bh == NULL) {
 100                 QNX4DEBUG(("qnx4: NULL symlink bh\n"));
 101                 return 0;
 102         }
 103         if (bh->b_data[0] != 0) {
 104                 i = 0;
 105                 while (i < buflen && (c = bh->b_data[i])) {
 106                         i++;
 107                         put_user(c, buffer++);
 108                 }
 109                 brelse(bh);
 110                 return i;
 111         } else {
 112                 brelse(bh);
 113                 memcpy(buffer, "fixme", 5);
 114                 return 5;
 115         }
 116 }