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