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/*
* linux/fs/ext2/symlink.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/symlink.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext2 symlink handling code
*/
#include <asm/segment.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/sched.h>
#include <linux/stat.h>
static int ext2_readlink (struct inode *, char *, int);
static int ext2_follow_link (struct inode *, struct inode *, int, int,
struct inode **);
/*
* symlinks can't do much...
*/
struct inode_operations ext2_symlink_inode_operations = {
NULL, /* no file-operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
ext2_readlink, /* readlink */
ext2_follow_link, /* follow_link */
NULL, /* readpage */
NULL, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL, /* permission */
NULL /* smap */
};
static int ext2_follow_link(struct inode * dir, struct inode * inode,
int flag, int mode, struct inode ** res_inode)
{
int error;
struct buffer_head * bh = NULL;
char * link;
*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) {
if (!(bh = ext2_bread (inode, 0, 0, &error))) {
iput (dir);
iput (inode);
return -EIO;
}
link = bh->b_data;
} else
link = (char *) inode->u.ext2_i.i_data;
UPDATE_ATIME(inode);
current->link_count++;
error = open_namei (link, flag, mode, res_inode, dir);
current->link_count--;
iput (inode);
if (bh)
brelse (bh);
return error;
}
static int ext2_readlink (struct inode * inode, char * buffer, int buflen)
{
struct buffer_head * bh = NULL;
char * link;
int i, err;
char c;
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) {
bh = ext2_bread (inode, 0, 0, &err);
if (!bh) {
iput (inode);
return 0;
}
link = bh->b_data;
}
else
link = (char *) inode->u.ext2_i.i_data;
i = 0;
while (i < buflen && (c = link[i])) {
i++;
put_user (c, buffer++);
}
UPDATE_ATIME(inode);
iput (inode);
if (bh)
brelse (bh);
return i;
}
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