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gerrit-public.fairphone.software / kernel / msm-4.9 / d38fde84f7521973fdfa5c3d03d62f014b42cd03 / . / fs / ncpfs / symlink.c
blob: e935f1b34bc2935e589979ee69c32a2fada36863 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]1/*
2 * linux/fs/ncpfs/symlink.c
3 *
4 * Code for allowing symbolic links on NCPFS (i.e. NetWare)
5 * Symbolic links are not supported on native NetWare, so we use an
6 * infrequently-used flag (Sh) and store a two-word magic header in
7 * the file to make sure we don't accidentally use a non-link file
8 * as a link.
9 *
10 * When using the NFS namespace, we set the mode to indicate a symlink and
11 * don't bother with the magic numbers.
12 *
13 * from linux/fs/ext2/symlink.c
14 *
15 * Copyright (C) 1998-99, Frank A. Vorstenbosch
16 *
17 * ncpfs symlink handling code
18 * NLS support (c) 1999 Petr Vandrovec
19 * Modified 2000 Ben Harris, University of Cambridge for NFS NS meta-info
20 *
21 */
22
23#include <linux/config.h>
24
25#include <asm/uaccess.h>
26
27#include <linux/errno.h>
28#include <linux/fs.h>
29#include <linux/ncp_fs.h>
30#include <linux/time.h>
31#include <linux/mm.h>
32#include <linux/stat.h>
33#include "ncplib_kernel.h"
34
35
36/* these magic numbers must appear in the symlink file -- this makes it a bit
37 more resilient against the magic attributes being set on random files. */
38
39#define NCP_SYMLINK_MAGIC0 cpu_to_le32(0x6c6d7973) /* "symlnk->" */
40#define NCP_SYMLINK_MAGIC1 cpu_to_le32(0x3e2d6b6e)
41
42/* ----- read a symbolic link ------------------------------------------ */
43
44static int ncp_symlink_readpage(struct file *file, struct page *page)
45{
46 struct inode *inode = page->mapping->host;
47 int error, length, len;
48 char *link, *rawlink;
49 char *buf = kmap(page);
50
51 error = -ENOMEM;
52 rawlink=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL);
53 if (!rawlink)
54 goto fail;
55
56 if (ncp_make_open(inode,O_RDONLY))
57 goto failEIO;
58
59 error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle,
60 0,NCP_MAX_SYMLINK_SIZE,rawlink,&length);
61
62 ncp_inode_close(inode);
63 /* Close file handle if no other users... */
64 ncp_make_closed(inode);
65 if (error)
66 goto failEIO;
67
68 if (NCP_FINFO(inode)->flags & NCPI_KLUDGE_SYMLINK) {
69 if (length<NCP_MIN_SYMLINK_SIZE ||
70 ((__le32 *)rawlink)[0]!=NCP_SYMLINK_MAGIC0 ||
71 ((__le32 *)rawlink)[1]!=NCP_SYMLINK_MAGIC1)
72 goto failEIO;
73 link = rawlink + 8;
74 length -= 8;
75 } else {
76 link = rawlink;
77 }
78
79 len = NCP_MAX_SYMLINK_SIZE;
80 error = ncp_vol2io(NCP_SERVER(inode), buf, &len, link, length, 0);
81 kfree(rawlink);
82 if (error)
83 goto fail;
84 SetPageUptodate(page);
85 kunmap(page);
86 unlock_page(page);
87 return 0;
88
89failEIO:
90 error = -EIO;
91 kfree(rawlink);
92fail:
93 SetPageError(page);
94 kunmap(page);
95 unlock_page(page);
96 return error;
97}
98
99/*
100 * symlinks can't do much...
101 */
102struct address_space_operations ncp_symlink_aops = {
103 .readpage = ncp_symlink_readpage,
104};
105
106/* ----- create a new symbolic link -------------------------------------- */
107
108int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) {
109 struct inode *inode;
110 char *rawlink;
111 int length, err, i, outlen;
112 int kludge;
113 int mode;
114 __le32 attr;
115 unsigned int hdr;
116
117 DPRINTK("ncp_symlink(dir=%p,dentry=%p,symname=%s)\n",dir,dentry,symname);
118
119 if (ncp_is_nfs_extras(NCP_SERVER(dir), NCP_FINFO(dir)->volNumber))
120 kludge = 0;
121 else
122#ifdef CONFIG_NCPFS_EXTRAS
123 if (NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS)
124 kludge = 1;
125 else
126#endif
127 /* EPERM is returned by VFS if symlink procedure does not exist */
128 return -EPERM;
129
130 rawlink=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL);
131 if (!rawlink)
132 return -ENOMEM;
133
134 if (kludge) {
135 mode = 0;
136 attr = aSHARED | aHIDDEN;
137 ((__le32 *)rawlink)[0]=NCP_SYMLINK_MAGIC0;
138 ((__le32 *)rawlink)[1]=NCP_SYMLINK_MAGIC1;
139 hdr = 8;
140 } else {
141 mode = S_IFLNK | S_IRWXUGO;
142 attr = 0;
143 hdr = 0;
144 }
145
146 length = strlen(symname);
147 /* map to/from server charset, do not touch upper/lower case as
148 symlink can point out of ncp filesystem */
149 outlen = NCP_MAX_SYMLINK_SIZE - hdr;
150 err = ncp_io2vol(NCP_SERVER(dir), rawlink + hdr, &outlen, symname, length, 0);
151 if (err)
152 goto failfree;
153
154 outlen += hdr;
155
156 err = -EIO;
157 if (ncp_create_new(dir,dentry,mode,0,attr)) {
158 goto failfree;
159 }
160
161 inode=dentry->d_inode;
162
163 if (ncp_make_open(inode, O_WRONLY))
164 goto failfree;
165
166 if (ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle,
167 0, outlen, rawlink, &i) || i!=outlen) {
168 goto fail;
169 }
170
171 ncp_inode_close(inode);
172 ncp_make_closed(inode);
173 kfree(rawlink);
174 return 0;
175fail:;
176 ncp_inode_close(inode);
177 ncp_make_closed(inode);
178failfree:;
179 kfree(rawlink);
180 return err;
181}
182
183/* ----- EOF ----- */