1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
/*
* linux/fs/nfs/symlink.c
*
* Copyright (C) 1992 Rick Sladkey
*
* nfs symlink handling code
*/
#include <asm/segment.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/nfs_fs.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/malloc.h>
static int nfs_readlink(struct inode *, char *, int);
static int nfs_follow_link(struct inode *, struct inode *, int, int,
struct inode **);
/*
* symlinks can't do much...
*/
struct inode_operations nfs_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 */
nfs_readlink, /* readlink */
nfs_follow_link, /* follow_link */
NULL, /* bmap */
NULL, /* truncate */
NULL /* permission */
};
static int nfs_follow_link(struct inode *dir, struct inode *inode,
int flag, int mode, struct inode **res_inode)
{
int error;
char *res;
*res_inode = NULL;
if (!dir) {
dir = current->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;
}
res = (char *) kmalloc(NFS_MAXPATHLEN + 1, GFP_KERNEL);
error = nfs_proc_readlink(NFS_SERVER(inode), NFS_FH(inode), res);
if (error) {
iput(inode);
iput(dir);
kfree_s(res, NFS_MAXPATHLEN + 1);
return error;
}
iput(inode);
current->link_count++;
error = open_namei(res, flag, mode, res_inode, dir);
current->link_count--;
kfree_s(res, NFS_MAXPATHLEN + 1);
return error;
}
static int nfs_readlink(struct inode *inode, char *buffer, int buflen)
{
int i;
char c;
int error;
char *res;
if (!S_ISLNK(inode->i_mode)) {
iput(inode);
return -EINVAL;
}
if (buflen > NFS_MAXPATHLEN)
buflen = NFS_MAXPATHLEN;
res = (char *) kmalloc(buflen + 1, GFP_KERNEL);
error = nfs_proc_readlink(NFS_SERVER(inode), NFS_FH(inode), res);
iput(inode);
if (error) {
kfree_s(res, buflen + 1);
return error;
}
for (i = 0; i < buflen && (c = res[i]); i++)
put_fs_byte(c,buffer++);
kfree_s(res, buflen + 1);
return i;
}