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/udf_fs.h>
27#include <linux/time.h>
28#include <linux/mm.h>
29#include <linux/stat.h>
30#include <linux/slab.h>
31#include <linux/pagemap.h>
32#include <linux/smp_lock.h>
33#include <linux/buffer_head.h>
34#include "udf_i.h"
35
36static void udf_pc_to_char(struct super_block *sb, char *from, int fromlen, char *to)
37{
38	struct pathComponent *pc;
39	int elen = 0;
40	char *p = to;
41
42	while (elen < fromlen)
43	{
44		pc = (struct pathComponent *)(from + elen);
45		switch (pc->componentType)
46		{
47			case 1:
48				if (pc->lengthComponentIdent == 0)
49				{
50					p = to;
51					*p++ = '/';
52				}
53				break;
54			case 3:
55				memcpy(p, "../", 3);
56				p += 3;
57				break;
58			case 4:
59				memcpy(p, "./", 2);
60				p += 2;
61				/* that would be . - just ignore */
62				break;
63			case 5:
64				p += udf_get_filename(sb, pc->componentIdent, p, pc->lengthComponentIdent);
65				*p++ = '/';
66				break;
67		}
68		elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
69	}
70	if (p > to+1)
71		p[-1] = '\0';
72	else
73		p[0] = '\0';
74}
75
76static int udf_symlink_filler(struct file *file, struct page *page)
77{
78	struct inode *inode = page->mapping->host;
79	struct buffer_head *bh = NULL;
80	char *symlink;
81	int err = -EIO;
82	char *p = kmap(page);
83
84	lock_kernel();
85	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
86		symlink = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
87	else
88	{
89		bh = sb_bread(inode->i_sb, udf_block_map(inode, 0));
90
91		if (!bh)
92			goto out;
93
94		symlink = bh->b_data;
95	}
96
97	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);
98	brelse(bh);
99
100	unlock_kernel();
101	SetPageUptodate(page);
102	kunmap(page);
103	unlock_page(page);
104	return 0;
105out:
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 */
116const struct address_space_operations udf_symlink_aops = {
117	.readpage		= udf_symlink_filler,
118};
119