fs/xiafs/symlink.c

/* */
This source file includes following definitions.
xiafs_readlink
xiafs_follow_link
   1 /*
   2  *  linux/fs/xiafs/symlink.c
   3  *
   4  *  Copyright (C) Q. Frank Xia, 1993.
   5  *  
   6  *  Based on Linus' minix/symlink.c
   7  *  Copyright (C) Linus Torvalds, 1991, 1992.
   8  *
   9  *  This software may be redistributed per Linux Copyright.
  10  */
  11 
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/fs.h>
  15 #include <linux/xia_fs.h>
  16 #include <linux/stat.h>
  17 
  18 #include <asm/segment.h>
  19 
  20 static int 
  21 xiafs_readlink(struct inode *, char *, int);
  22 
  23 static int 
  24 xiafs_follow_link(struct inode *, struct inode *, int, int, struct inode **);
  25 
  26 /*
  27  * symlinks can't do much...
  28  */
  29 struct inode_operations xiafs_symlink_inode_operations = {
  30         NULL,                   /* no file-operations */
  31         NULL,                   /* create */
  32         NULL,                   /* lookup */
  33         NULL,                   /* link */
  34         NULL,                   /* unlink */
  35         NULL,                   /* symlink */
  36         NULL,                   /* mkdir */
  37         NULL,                   /* rmdir */
  38         NULL,                   /* mknod */
  39         NULL,                   /* rename */
  40         xiafs_readlink,         /* readlink */
  41         xiafs_follow_link,      /* follow_link */
  42         NULL,                   /* readpage */
  43         NULL,                   /* writepage */
  44         NULL,                   /* bmap */
  45         NULL,                   /* truncate */
  46         NULL                    /* permission */
  47 };
  48 
  49 static int xiafs_readlink(struct inode * inode, char * buffer, int buflen)
     /*  */
  50 {
  51     struct buffer_head * bh;
  52     int i;
  53     char c;
  54 
  55     if (!S_ISLNK(inode->i_mode)) {
  56         iput(inode);
  57         return -EINVAL;
  58     }
  59     if (buflen > BLOCK_SIZE)
  60         buflen = BLOCK_SIZE;
  61     bh = xiafs_bread(inode, 0, 0);
  62     if (!IS_RDONLY (inode)) {
  63         inode->i_atime=CURRENT_TIME;
  64         inode->i_dirt=1;
  65     }
  66     iput(inode);
  67     if (!bh)
  68         return 0;
  69     for (i=0; i < buflen && (c=bh->b_data[i]); i++)
  70       put_user(c, buffer++);
  71     if (i < buflen-1)
  72       put_user('\0', buffer);
  73     brelse(bh);
  74     return i;
  75 }
  76 
  77 static int xiafs_follow_link(struct inode * dir, struct inode * inode,
     /*  */
  78         int flag, int mode, struct inode ** res_inode)
  79 {
  80     int error;
  81     struct buffer_head * bh;
  82 
  83     *res_inode = NULL;
  84     if (!dir) {
  85         dir = current->fs->root;
  86         dir->i_count++;
  87     }
  88     if (!inode) {
  89         iput(dir);
  90         return -ENOENT;
  91     }
  92     if (!S_ISLNK(inode->i_mode)) {
  93         iput(dir);
  94         *res_inode = inode;
  95         return 0;
  96     }
  97     if (!IS_RDONLY (inode)) {
  98         inode->i_atime=CURRENT_TIME;
  99         inode->i_dirt=1;
 100     }
 101     if (current->link_count > 5) {
 102         iput(inode);
 103         iput(dir);
 104         return -ELOOP;
 105     }
 106     if (!(bh = xiafs_bread(inode, 0, 0))) {
 107         iput(inode);
 108         iput(dir);
 109         return -EIO;
 110     }
 111     iput(inode);
 112     current->link_count++;
 113     error = open_namei(bh->b_data,flag,mode,res_inode,dir);
 114     current->link_count--;
 115     brelse(bh);
 116     return error;
 117 }
 118 
 119 
 120
/* */
root/fs/xiafs/symlink.c

DEFINITIONS
