161 lines
3.3 KiB
C
161 lines
3.3 KiB
C
/*
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* symlink.c
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*
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* PURPOSE
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* Symlink handling routines for the OSTA-UDF(tm) filesystem.
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*
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* COPYRIGHT
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* This file is distributed under the terms of the GNU General Public
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* License (GPL). Copies of the GPL can be obtained from:
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* ftp://prep.ai.mit.edu/pub/gnu/GPL
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* Each contributing author retains all rights to their own work.
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*
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* (C) 1998-2001 Ben Fennema
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* (C) 1999 Stelias Computing Inc
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*
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* HISTORY
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*
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* 04/16/99 blf Created.
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*
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*/
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#include "udfdecl.h"
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#include <linux/uaccess.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/time.h>
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#include <linux/mm.h>
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#include <linux/stat.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include "udf_i.h"
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static int udf_pc_to_char(struct super_block *sb, unsigned char *from,
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int fromlen, unsigned char *to, int tolen)
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{
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struct pathComponent *pc;
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int elen = 0;
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int comp_len;
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unsigned char *p = to;
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/* Reserve one byte for terminating \0 */
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tolen--;
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while (elen < fromlen) {
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pc = (struct pathComponent *)(from + elen);
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elen += sizeof(struct pathComponent);
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switch (pc->componentType) {
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case 1:
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/*
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* Symlink points to some place which should be agreed
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* upon between originator and receiver of the media. Ignore.
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*/
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if (pc->lengthComponentIdent > 0) {
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elen += pc->lengthComponentIdent;
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break;
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}
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/* Fall through */
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case 2:
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if (tolen == 0)
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return -ENAMETOOLONG;
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p = to;
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*p++ = '/';
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tolen--;
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break;
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case 3:
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if (tolen < 3)
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return -ENAMETOOLONG;
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memcpy(p, "../", 3);
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p += 3;
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tolen -= 3;
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break;
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case 4:
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if (tolen < 2)
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return -ENAMETOOLONG;
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memcpy(p, "./", 2);
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p += 2;
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tolen -= 2;
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/* that would be . - just ignore */
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break;
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case 5:
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elen += pc->lengthComponentIdent;
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if (elen > fromlen)
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return -EIO;
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comp_len = udf_get_filename(sb, pc->componentIdent,
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pc->lengthComponentIdent,
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p, tolen);
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p += comp_len;
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tolen -= comp_len;
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if (tolen == 0)
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return -ENAMETOOLONG;
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*p++ = '/';
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tolen--;
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break;
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}
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}
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if (p > to + 1)
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p[-1] = '\0';
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else
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p[0] = '\0';
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return 0;
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}
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static int udf_symlink_filler(struct file *file, struct page *page)
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{
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struct inode *inode = page->mapping->host;
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struct buffer_head *bh = NULL;
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unsigned char *symlink;
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int err;
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unsigned char *p = kmap(page);
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struct udf_inode_info *iinfo;
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uint32_t pos;
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/* We don't support symlinks longer than one block */
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if (inode->i_size > inode->i_sb->s_blocksize) {
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err = -ENAMETOOLONG;
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goto out_unmap;
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}
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iinfo = UDF_I(inode);
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pos = udf_block_map(inode, 0);
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down_read(&iinfo->i_data_sem);
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if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
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symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
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} else {
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bh = sb_bread(inode->i_sb, pos);
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if (!bh) {
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err = -EIO;
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goto out_unlock_inode;
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}
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symlink = bh->b_data;
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}
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err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE);
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brelse(bh);
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if (err)
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goto out_unlock_inode;
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up_read(&iinfo->i_data_sem);
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SetPageUptodate(page);
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kunmap(page);
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unlock_page(page);
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return 0;
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out_unlock_inode:
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up_read(&iinfo->i_data_sem);
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SetPageError(page);
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out_unmap:
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kunmap(page);
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unlock_page(page);
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return err;
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}
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/*
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* symlinks can't do much...
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*/
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const struct address_space_operations udf_symlink_aops = {
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.readpage = udf_symlink_filler,
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};
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