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/*
* linux/fs/ufs/ufs_symlink.c
*
* Copyright (C) 1996
* Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
* Laboratory for Computer Science Research Computing Facility
* Rutgers, The State University of New Jersey
*
* $Id: ufs_symlink.c,v 1.7 1997/01/26 07:14:29 davem Exp $
*
*/
#include <linux/fs.h>
#include <linux/ufs_fs.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
static int
ufs_readlink(struct inode * inode, char * buffer, int buflen)
{
unsigned long int block;
struct buffer_head * bh = NULL;
char * link;
int i;
char c;
if (inode->i_sb->u.ufs_sb.s_flags & (UFS_DEBUG|UFS_DEBUG_LINKS)) {
printk("ufs_readlink: called on ino %lu dev %u/%u\n",
inode->i_ino, MAJOR(inode->i_dev), MINOR(inode->i_dev));
}
if (!S_ISLNK(inode->i_mode)) {
iput (inode);
return -EINVAL;
}
if (buflen > inode->i_sb->s_blocksize - 1)
buflen = inode->i_sb->s_blocksize - 1;
if (inode->i_blocks) {
/* XXX - error checking */
block = ufs_bmap(inode, 0);
if (inode->i_sb->u.ufs_sb.s_flags &(UFS_DEBUG|UFS_DEBUG_LINKS)) {
printk("ufs_readlink: bmap got %lu for ino %lu\n",
block, inode->i_ino);
}
bh = bread(inode->i_dev, block, BLOCK_SIZE);
if (!bh) {
iput (inode);
printk("ufs_readlink: can't read block 0 for ino %lu on dev %u/%u\n",
inode->i_ino, MAJOR(inode->i_dev),
MINOR(inode->i_dev));
return 0;
}
link = bh->b_data;
}
else {
link = (char *)&(inode->u.ufs_i.i_data[0]);
}
i = 0;
while (i < buflen && (c = link[i])) {
i++;
put_user (c, buffer++);
}
iput (inode);
if (bh)
brelse (bh);
return i;
}
/*
* XXX - blatantly stolen from ext2fs
*/
static int
ufs_follow_link(struct inode * dir, struct inode * inode,
int flag, int mode, struct inode ** res_inode)
{
unsigned long int block;
int error;
struct buffer_head * bh;
char * link;
bh = NULL;
if (inode->i_sb->u.ufs_sb.s_flags & (UFS_DEBUG|UFS_DEBUG_LINKS)) {
printk("ufs_follow_link: called on ino %lu dev %u/%u\n",
dir->i_ino, MAJOR(dir->i_dev), MINOR(dir->i_dev));
}
*res_inode = NULL;
if (!dir) {
dir = current->fs->root;
dir->i_count++;
}
if (!inode) {
iput (dir);
return -ENOENT;
}
if (!S_ISLNK(inode->i_mode)) {
iput (dir);
*res_inode = inode;
return 0;
}
if (current->link_count > 5) {
iput (dir);
iput (inode);
return -ELOOP;
}
if (inode->i_blocks) {
/* read the link from disk */
/* XXX - error checking */
block = ufs_bmap(inode, 0);
bh = bread(inode->i_dev, block, BLOCK_SIZE);
if (bh == NULL) {
printk("ufs_follow_link: can't read block 0 for ino %lu on dev %u/%u\n",
inode->i_ino, MAJOR(inode->i_dev),
MINOR(inode->i_dev));
iput(dir);
iput(inode);
return(-EIO);
}
link = bh->b_data;
} else {
/* fast symlink */
link = (char *)&(inode->u.ufs_i.i_data[0]);
}
current->link_count++;
error = open_namei (link, flag, mode, res_inode, dir);
current->link_count--;
iput (inode);
if (bh) {
brelse (bh);
}
return(error);
}
static struct file_operations ufs_symlink_operations = {
NULL, /* lseek */
NULL, /* read */
NULL, /* write */
NULL, /* readdir */
NULL, /* poll */
NULL, /* ioctl */
NULL, /* mmap */
NULL, /* open */
NULL, /* release */
NULL, /* fsync */ /* XXX - is this ok? */
NULL, /* fasync */
NULL, /* check_media_change */
NULL, /* revalidate */
};
struct inode_operations ufs_symlink_inode_operations = {
&ufs_symlink_operations, /* default directory file operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
&ufs_readlink, /* readlink */
&ufs_follow_link, /* follow_link */
NULL, /* readpage */
NULL, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL, /* permission */
NULL, /* smap */
};
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