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@hootie.lvld.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) 1998-2000 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/sched.h>
33 #include <linux/mm.h>
34 #include <linux/stat.h>
35 #include <linux/malloc.h>
36 #include <linux/pagemap.h>
37 #include <linux/smp_lock.h>
38 #include "udf_i.h"
39
40 static void udf_pc_to_char(char *from, int fromlen, char *to)
41 {
42 struct PathComponent *pc;
43 int elen = 0;
44 char *p = to;
45
46 while (elen < fromlen)
47 {
48 pc = (struct PathComponent *)(from + elen);
49 switch (pc->componentType)
50 {
51 case 1:
52 if (pc->lengthComponentIdent == 0)
53 {
54 p = to;
55 *p++ = '/';
56 }
57 break;
58 case 3:
59 memcpy(p, "../", 3);
60 p += 3;
61 break;
62 case 4:
63 memcpy(p, "./", 2);
64 p += 2;
65 /* that would be . - just ignore */
66 break;
67 case 5:
68 memcpy(p, pc->componentIdent, pc->lengthComponentIdent);
69 p += pc->lengthComponentIdent;
70 *p++ = '/';
71 }
72 elen += sizeof(struct PathComponent) + pc->lengthComponentIdent;
73 }
74 if (p > to+1)
75 p[-1] = '\0';
76 else
77 p[0] = '\0';
78 }
79
80 static int udf_symlink_filler(struct file *file, struct page *page)
81 {
82 struct inode *inode = page->mapping->host;
83 struct buffer_head *bh = NULL;
84 char *symlink;
85 int err = -EIO;
86 char *p = kmap(page);
87
88 lock_kernel();
89 if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
90 {
91 bh = udf_tread(inode->i_sb, inode->i_ino, inode->i_sb->s_blocksize);
92
93 if (!bh)
94 goto out;
95
96 symlink = bh->b_data + udf_file_entry_alloc_offset(inode);
97 }
98 else
99 {
100 bh = bread(inode->i_dev, udf_block_map(inode, 0),
101 inode->i_sb->s_blocksize);
102
103 if (!bh)
104 goto out;
105
106 symlink = bh->b_data;
107 }
108
109 udf_pc_to_char(symlink, inode->i_size, p);
110 udf_release_data(bh);
111
112 unlock_kernel();
113 SetPageUptodate(page);
114 kunmap(page);
115 UnlockPage(page);
116 return 0;
117 out:
118 unlock_kernel();
119 SetPageError(page);
120 kunmap(page);
121 UnlockPage(page);
122 return err;
123 }
124
125 /*
126 * symlinks can't do much...
127 */
128 struct address_space_operations udf_symlink_aops = {
129 readpage: udf_symlink_filler,
130 };
131
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