[linux.git] / fs / udf / symlink.c

/*
 * symlink.c
 *
 * PURPOSE
 *	Symlink handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 *
 *  (C) 1998-2001 Ben Fennema
 *  (C) 1999 Stelias Computing Inc
 *
 * HISTORY
 *
 *  04/16/99 blf  Created.
 *
 */

#include "udfdecl.h"
#include <linux/uaccess.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include "udf_i.h"

static void udf_pc_to_char(struct super_block *sb, unsigned char *from,
			   int fromlen, unsigned char *to)
{
	struct pathComponent *pc;
	int elen = 0;
	unsigned char *p = to;

	while (elen < fromlen) {
		pc = (struct pathComponent *)(from + elen);
		switch (pc->componentType) {
		case 1:
			/*
			 * Symlink points to some place which should be agreed
 			 * upon between originator and receiver of the media. Ignore.
			 */
			if (pc->lengthComponentIdent > 0)
				break;
			/* Fall through */
		case 2:
			p = to;
			*p++ = '/';
			break;
		case 3:
			memcpy(p, "../", 3);
			p += 3;
			break;
		case 4:
			memcpy(p, "./", 2);
			p += 2;
			/* that would be . - just ignore */
			break;
		case 5:
			p += udf_get_filename(sb, pc->componentIdent, p,
					      pc->lengthComponentIdent);
			*p++ = '/';
			break;
		}
		elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
	}
	if (p > to + 1)
		p[-1] = '\0';
	else
		p[0] = '\0';
}

static int udf_symlink_filler(struct file *file, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct buffer_head *bh = NULL;
	unsigned char *symlink;
	int err = -EIO;
	unsigned char *p = kmap(page);
	struct udf_inode_info *iinfo;
	uint32_t pos;

	iinfo = UDF_I(inode);
	pos = udf_block_map(inode, 0);

	down_read(&iinfo->i_data_sem);
	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
		symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
	} else {
		bh = sb_bread(inode->i_sb, pos);

		if (!bh)
			goto out;

		symlink = bh->b_data;
	}

	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);
	brelse(bh);

	up_read(&iinfo->i_data_sem);
	SetPageUptodate(page);
	kunmap(page);
	unlock_page(page);
	return 0;

out:
	up_read(&iinfo->i_data_sem);
	SetPageError(page);
	kunmap(page);
	unlock_page(page);
	return err;
}

/*
 * symlinks can't do much...
 */
const struct address_space_operations udf_symlink_aops = {
	.readpage		= udf_symlink_filler,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* symlink.c
	3	*
	4	* PURPOSE
	5	* Symlink handling routines for the OSTA-UDF(tm) filesystem.
	6	*
1da177e4 LT	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
28de7948	14	* (C) 1999 Stelias Computing Inc
1da177e4 LT	15	*
	16	* HISTORY
	17	*
	18	* 04/16/99 blf Created.
	19	*
	20	*/
	21
	22	#include "udfdecl.h"
e973606c	23	#include <linux/uaccess.h>
1da177e4 LT	24	#include <linux/errno.h>
1da177e4 LT	25	#include <linux/fs.h>
1da177e4 LT	26	#include <linux/time.h>
	27	#include <linux/mm.h>
	28	#include <linux/stat.h>
1da177e4	29	#include <linux/pagemap.h>
1da177e4 LT	30	#include <linux/buffer_head.h>
	31	#include "udf_i.h"
	32
391e8bbd AV	33	static void udf_pc_to_char(struct super_block sb, unsigned char from,
391e8bbd AV	34	int fromlen, unsigned char *to)
1da177e4 LT	35	{
	36	struct pathComponent *pc;
	37	int elen = 0;
391e8bbd	38	unsigned char *p = to;
1da177e4	39
cb00ea35	40	while (elen < fromlen) {
1da177e4	41	pc = (struct pathComponent *)(from + elen);
cb00ea35 CG	42	switch (pc->componentType) {
cb00ea35 CG	43	case 1:
fef2e9f3 JK	44	/*
	45	* Symlink points to some place which should be agreed
	46	* upon between originator and receiver of the media. Ignore.
	47	*/
	48	if (pc->lengthComponentIdent > 0)
	49	break;
	50	/* Fall through */
	51	case 2:
	52	p = to;
	53	*p++ = '/';
cb00ea35 CG	54	break;
	55	case 3:
	56	memcpy(p, "../", 3);
	57	p += 3;
	58	break;
	59	case 4:
	60	memcpy(p, "./", 2);
	61	p += 2;
	62	/* that would be . - just ignore */
	63	break;
	64	case 5:
	65	p += udf_get_filename(sb, pc->componentIdent, p,
	66	pc->lengthComponentIdent);
	67	*p++ = '/';
	68	break;
1da177e4 LT	69	}
	70	elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
	71	}
cb00ea35	72	if (p > to + 1)
1da177e4 LT	73	p[-1] = '\0';
	74	else
	75	p[0] = '\0';
	76	}
	77
	78	static int udf_symlink_filler(struct file file, struct page page)
	79	{
	80	struct inode *inode = page->mapping->host;
	81	struct buffer_head *bh = NULL;
391e8bbd	82	unsigned char *symlink;
1da177e4	83	int err = -EIO;
391e8bbd	84	unsigned char *p = kmap(page);
48d6d8ff	85	struct udf_inode_info *iinfo;
4d0fb621	86	uint32_t pos;
1da177e4	87
48d6d8ff	88	iinfo = UDF_I(inode);
4d0fb621 AIB	89	pos = udf_block_map(inode, 0);
	90
	91	down_read(&iinfo->i_data_sem);
48d6d8ff MS	92	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
48d6d8ff MS	93	symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
28de7948	94	} else {
4d0fb621	95	bh = sb_bread(inode->i_sb, pos);
1da177e4 LT	96
	97	if (!bh)
	98	goto out;
	99
	100	symlink = bh->b_data;
	101	}
	102
	103	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);
3bf25cb4	104	brelse(bh);
1da177e4	105
4d0fb621	106	up_read(&iinfo->i_data_sem);
1da177e4 LT	107	SetPageUptodate(page);
	108	kunmap(page);
	109	unlock_page(page);
	110	return 0;
28de7948 CG	111
28de7948 CG	112	out:
4d0fb621	113	up_read(&iinfo->i_data_sem);
1da177e4 LT	114	SetPageError(page);
	115	kunmap(page);
	116	unlock_page(page);
	117	return err;
	118	}
	119
	120	/*
	121	* symlinks can't do much...
	122	*/
f5e54d6e	123	const struct address_space_operations udf_symlink_aops = {
28de7948	124	.readpage = udf_symlink_filler,
1da177e4	125	};