43f3051ef756484c58d14b959d42bb26f103b83a
[linux-2.6.git] / fs / udf / symlink.c
1 /*
2  * symlink.c
3  *
4  * PURPOSE
5  *      Symlink handling routines for the OSTA-UDF(tm) filesystem.
6  *
7  * CONTACTS
8  *      E-mail regarding any portion of the Linux UDF file system should be
9  *      directed to the development team mailing list (run by majordomo):
10  *              linux_udf@hpesjro.fc.hp.com
11  *
12  * COPYRIGHT
13  *      This file is distributed under the terms of the GNU General Public
14  *      License (GPL). Copies of the GPL can be obtained from:
15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
16  *      Each contributing author retains all rights to their own work.
17  *
18  *  (C) 1998-2001 Ben Fennema
19  *  (C) 1999 Stelias Computing Inc 
20  *
21  * HISTORY
22  *
23  *  04/16/99 blf  Created.
24  *
25  */
26
27 #include "udfdecl.h"
28 #include <asm/uaccess.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/udf_fs.h>
32 #include <linux/time.h>
33 #include <linux/mm.h>
34 #include <linux/stat.h>
35 #include <linux/slab.h>
36 #include <linux/pagemap.h>
37 #include <linux/smp_lock.h>
38 #include <linux/buffer_head.h>
39 #include "udf_i.h"
40
41 static void udf_pc_to_char(struct super_block *sb, char *from, int fromlen, char *to)
42 {
43         struct pathComponent *pc;
44         int elen = 0;
45         char *p = to;
46
47         while (elen < fromlen)
48         {
49                 pc = (struct pathComponent *)(from + elen);
50                 switch (pc->componentType)
51                 {
52                         case 1:
53                                 if (pc->lengthComponentIdent == 0)
54                                 {
55                                         p = to;
56                                         *p++ = '/';
57                                 }
58                                 break;
59                         case 3:
60                                 memcpy(p, "../", 3);
61                                 p += 3;
62                                 break;
63                         case 4:
64                                 memcpy(p, "./", 2);
65                                 p += 2;
66                                 /* that would be . - just ignore */
67                                 break;
68                         case 5:
69                                 p += udf_get_filename(sb, pc->componentIdent, p, pc->lengthComponentIdent);
70                                 *p++ = '/';
71                                 break;
72                 }
73                 elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
74         }
75         if (p > to+1)
76                 p[-1] = '\0';
77         else
78                 p[0] = '\0';
79 }
80
81 static int udf_symlink_filler(struct file *file, struct page *page)
82 {
83         struct inode *inode = page->mapping->host;
84         struct buffer_head *bh = NULL;
85         char *symlink;
86         int err = -EIO;
87         char *p = kmap(page);
88
89         lock_kernel();
90         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
91                 symlink = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
92         else
93         {
94                 bh = sb_bread(inode->i_sb, udf_block_map(inode, 0));
95
96                 if (!bh)
97                         goto out;
98
99                 symlink = bh->b_data;
100         }
101
102         udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);
103         udf_release_data(bh);
104
105         unlock_kernel();
106         SetPageUptodate(page);
107         kunmap(page);
108         unlock_page(page);
109         return 0;
110 out:
111         unlock_kernel();
112         SetPageError(page);
113         kunmap(page);
114         unlock_page(page);
115         return err;
116 }
117
118 /*
119  * symlinks can't do much...
120  */
121 struct address_space_operations udf_symlink_aops = {
122         .readpage               = udf_symlink_filler,
123 };