fs/affs/symlink.c

   1 /*
   2  *  linux/fs/affs/symlink.c
   3  *
   4  *  1995  Hans-Joachim Widmaier - Modified for affs.
   5  *
   6  *  Copyright (C) 1991, 1992  Linus Torvalds
   7  *
   8  *  affs symlink handling code
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/sched.h>
  13 #include <linux/malloc.h>
  14 #include <linux/fs.h>
  15 #include <linux/stat.h>
  16 #include <linux/affs_fs.h>
  17 #include <linux/amigaffs.h>
  18 #include <asm/uaccess.h>
  19
  20 #define MIN(a,b) (((a) < (b)) ? (a) : (b))
  21
  22 static int               affs_readlink(struct dentry *, char *, int);
  23 static struct dentry    *affs_follow_link(struct dentry *dentry, struct dentry *base, unsigned int);
  24
  25 struct inode_operations affs_symlink_inode_operations = {
  26         NULL,                   /* no file-operations */
  27         NULL,                   /* create */
  28         NULL,                   /* lookup */
  29         NULL,                   /* link */
  30         NULL,                   /* unlink */
  31         NULL,                   /* symlink */
  32         NULL,                   /* mkdir */
  33         NULL,                   /* rmdir */
  34         NULL,                   /* mknod */
  35         NULL,                   /* rename */
  36         affs_readlink,          /* readlink */
  37         affs_follow_link,       /* follow_link */
  38         NULL,                   /* get_block */
  39         NULL,                   /* readpage */
  40         NULL,                   /* writepage */
  41         NULL,                   /* flushpage */
  42         NULL,                   /* truncate */
  43         NULL,                   /* permission */
  44         NULL,                   /* smap */
  45         NULL                    /* revalidate */
  46 };
  47
  48 static int
  49 affs_readlink(struct dentry *dentry, char *buffer, int buflen)
  50 {
  51         struct inode *inode = dentry->d_inode;
  52         struct buffer_head      *bh;
  53         struct slink_front      *lf;
  54         int                      i, j;
  55         char                     c;
  56         char                     lc;
  57         char                    *pf;
  58
  59         pr_debug("AFFS: readlink(ino=%lu,buflen=%d)\n",inode->i_ino,buflen);
  60
  61         bh = affs_bread(inode->i_dev,inode->i_ino,AFFS_I2BSIZE(inode));
  62         if (!bh) {
  63                 affs_warning(inode->i_sb,"follow_link","Unable to read i-node block %lu\n",
  64                                 inode->i_ino);
  65                 return -EIO;
  66         }
  67         lf = (struct slink_front *)bh->b_data;
  68         lc = 0;
  69         i  = 0;
  70         j  = 0;
  71         pf = inode->i_sb->u.affs_sb.s_prefix ? inode->i_sb->u.affs_sb.s_prefix : "/";
  72
  73         if (strchr(lf->symname,':')) {          /* Handle assign or volume name */
  74                 while (i < buflen && (c = pf[i])) {
  75                         put_user(c,buffer++);
  76                         i++;
  77                 }
  78                 while (i < buflen && (c = lf->symname[j]) != ':') {
  79                         put_user(c,buffer++);
  80                         i++, j++;
  81                 }
  82                 if (i < buflen) {
  83                         put_user('/',buffer++);
  84                         i++, j++;
  85                 }
  86                 lc = '/';
  87         }
  88         while (i < buflen && (c = lf->symname[j])) {
  89                 if (c == '/' && lc == '/' && (i + 3 < buflen)) {        /* parent dir */
  90                         put_user('.',buffer++);
  91                         put_user('.',buffer++);
  92                         i += 2;
  93                 }
  94                 put_user(c,buffer++);
  95                 lc = c;
  96                 i++, j++;
  97         }
  98         affs_brelse(bh);
  99         return i;
 100 }
 101
 102 static struct dentry *
 103 affs_follow_link(struct dentry *dentry, struct dentry *base, unsigned int follow)
 104 {
 105         struct inode *inode = dentry->d_inode;
 106         struct buffer_head      *bh;
 107         struct slink_front      *lf;
 108         char                    *buffer;
 109         int                      i, j;
 110         char                     c;
 111         char                     lc;
 112         char                    *pf;
 113
 114         pr_debug("AFFS: follow_link(ino=%lu)\n",inode->i_ino);
 115
 116         if (!(buffer = kmalloc(1024,GFP_KERNEL))) {
 117                 dput(base);
 118                 return ERR_PTR(-ENOSPC);
 119         }
 120         bh = affs_bread(inode->i_dev,inode->i_ino,AFFS_I2BSIZE(inode));
 121         if (!bh) {
 122                 affs_warning(inode->i_sb,"follow_link","Unable to read i-node block %lu\n",
 123                                 inode->i_ino);
 124                 kfree(buffer);
 125                 dput(base);
 126                 return ERR_PTR(-EIO);
 127         }
 128         i  = 0;
 129         j  = 0;
 130         lf = (struct slink_front *)bh->b_data;
 131         lc = 0;
 132         pf = inode->i_sb->u.affs_sb.s_prefix ? inode->i_sb->u.affs_sb.s_prefix : "/";
 133
 134         if (strchr(lf->symname,':')) {          /* Handle assign or volume name */
 135                 while (i < 1023 && (c = pf[i]))
 136                         buffer[i++] = c;
 137                 while (i < 1023 && lf->symname[j] != ':')
 138                         buffer[i++] = lf->symname[j++];
 139                 if (i < 1023)
 140                          buffer[i++] = '/';
 141                 j++;
 142                 lc = '/';
 143         }
 144         while (i < 1023 && (c = lf->symname[j])) {
 145                 if (c == '/' && lc == '/' && i < 1020) {        /* parent dir */
 146                         buffer[i++] = '.';
 147                         buffer[i++] = '.';
 148                 }
 149                 buffer[i++] = c;
 150                 lc = c;
 151                 j++;
 152         }
 153         buffer[i] = '\0';
 154         affs_brelse(bh);
 155         base = lookup_dentry(buffer,base,follow);
 156         kfree(buffer);
 157         return base;
 158 }
 159