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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 | |
24 | #include <asm/uaccess.h> |
25 | |
26 | #include <linux/errno.h> |
27 | #include <linux/fs.h> |
28 | #include <linux/ncp_fs.h> |
29 | #include <linux/time.h> |
30 | #include <linux/slab.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 | |
44 | static 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 = 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 | |
89 | failEIO: |
90 | error = -EIO; |
91 | kfree(rawlink); |
92 | fail: |
93 | SetPageError(page); |
94 | kunmap(page); |
95 | unlock_page(page); |
96 | return error; |
97 | } |
98 | |
99 | /* |
100 | * symlinks can't do much... |
101 | */ |
102 | const struct address_space_operations ncp_symlink_aops = { |
103 | .readpage = ncp_symlink_readpage, |
104 | }; |
105 | |
106 | /* ----- create a new symbolic link -------------------------------------- */ |
107 | |
108 | int 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 = 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; |
175 | fail:; |
176 | ncp_inode_close(inode); |
177 | ncp_make_closed(inode); |
178 | failfree:; |
179 | kfree(rawlink); |
180 | return err; |
181 | } |
182 | |
183 | /* ----- EOF ----- */ |
184 |
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