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/pagemap.h>
30#include <linux/smp_lock.h>
31#include <linux/buffer_head.h>
32#include "udf_i.h"
33
34static void udf_pc_to_char(struct super_block *sb, unsigned char *from,
35			   int fromlen, unsigned char *to)
36{
37	struct pathComponent *pc;
38	int elen = 0;
39	unsigned char *p = to;
40
41	while (elen < fromlen) {
42		pc = (struct pathComponent *)(from + elen);
43		switch (pc->componentType) {
44		case 1:
45			if (pc->lengthComponentIdent == 0) {
46				p = to;
47				*p++ = '/';
48			}
49			break;
50		case 3:
51			memcpy(p, "../", 3);
52			p += 3;
53			break;
54		case 4:
55			memcpy(p, "./", 2);
56			p += 2;
57			/* that would be . - just ignore */
58			break;
59		case 5:
60			p += udf_get_filename(sb, pc->componentIdent, p,
61					      pc->lengthComponentIdent);
62			*p++ = '/';
63			break;
64		}
65		elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
66	}
67	if (p > to + 1)
68		p[-1] = '\0';
69	else
70		p[0] = '\0';
71}
72
73static int udf_symlink_filler(struct file *file, struct page *page)
74{
75	struct inode *inode = page->mapping->host;
76	struct buffer_head *bh = NULL;
77	unsigned char *symlink;
78	int err = -EIO;
79	unsigned char *p = kmap(page);
80	struct udf_inode_info *iinfo;
81
82	lock_kernel();
83	iinfo = UDF_I(inode);
84	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
85		symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
86	} else {
87		bh = sb_bread(inode->i_sb, udf_block_map(inode, 0));
88
89		if (!bh)
90			goto out;
91
92		symlink = bh->b_data;
93	}
94
95	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);
96	brelse(bh);
97
98	unlock_kernel();
99	SetPageUptodate(page);
100	kunmap(page);
101	unlock_page(page);
102	return 0;
103
104out:
105	unlock_kernel();
106	SetPageError(page);
107	kunmap(page);
108	unlock_page(page);
109	return err;
110}
111
112/*
113 * symlinks can't do much...
114 */
115const struct address_space_operations udf_symlink_aops = {
116	.readpage		= udf_symlink_filler,
117};
118