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/*
* linux/fs/sysv/symlink.c
*
* minix/symlink.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* coh/symlink.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/symlink.c
* Copyright (C) 1993 Bruno Haible
*
* SystemV/Coherent symlink handling code
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sysv_fs.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
static int sysv_readlink(struct inode *, char *, int);
static int sysv_follow_link(struct inode *, struct inode *, int, int, struct inode **);
/*
* symlinks can't do much...
*/
struct inode_operations sysv_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 */
sysv_readlink, /* readlink */
sysv_follow_link, /* follow_link */
NULL, /* readpage */
NULL, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL /* permission */
};
static int sysv_follow_link(struct inode * dir, struct inode * inode,
int flag, int mode, struct inode ** res_inode)
{
int error;
struct buffer_head * bh;
*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(inode);
iput(dir);
return -ELOOP;
}
if (!(bh = sysv_file_bread(inode, 0, 0))) { /* is reading 1 block enough ?? */
iput(inode);
iput(dir);
return -EIO;
}
iput(inode);
current->link_count++;
error = open_namei(bh->b_data,flag,mode,res_inode,dir);
current->link_count--;
brelse(bh);
return error;
}
static int sysv_readlink(struct inode * inode, char * buffer, int buflen)
{
struct buffer_head * bh;
char * bh_data;
int i;
char c;
if (!S_ISLNK(inode->i_mode)) {
iput(inode);
return -EINVAL;
}
if (buflen > inode->i_sb->sv_block_size_1)
buflen = inode->i_sb->sv_block_size_1;
bh = sysv_file_bread(inode, 0, 0);
iput(inode);
if (!bh)
return 0;
bh_data = bh->b_data;
i = 0;
while (i<buflen && (c = bh_data[i])) {
i++;
put_user(c,buffer++);
}
brelse(bh);
return i;
}
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