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172 lines
4.1 KiB
C
172 lines
4.1 KiB
C
/*
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* linux/fs/isofs/namei.c
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*
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* (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
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*
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* (C) 1991 Linus Torvalds - minix filesystem
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*/
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#include <linux/gfp.h>
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#include "isofs.h"
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/*
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* ok, we cannot use strncmp, as the name is not in our data space.
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* Thus we'll have to use isofs_match. No big problem. Match also makes
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* some sanity tests.
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*/
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static int
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isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
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{
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struct qstr qstr;
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qstr.name = compare;
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qstr.len = dlen;
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if (likely(!dentry->d_op))
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return dentry->d_name.len != dlen || memcmp(dentry->d_name.name, compare, dlen);
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return dentry->d_op->d_compare(NULL, dentry->d_name.len, dentry->d_name.name, &qstr);
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}
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/*
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* isofs_find_entry()
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*
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* finds an entry in the specified directory with the wanted name. It
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* returns the inode number of the found entry, or 0 on error.
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*/
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static unsigned long
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isofs_find_entry(struct inode *dir, struct dentry *dentry,
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unsigned long *block_rv, unsigned long *offset_rv,
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char *tmpname, struct iso_directory_record *tmpde)
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{
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unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
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unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
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unsigned long block, f_pos, offset, block_saved, offset_saved;
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struct buffer_head *bh = NULL;
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struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
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if (!ISOFS_I(dir)->i_first_extent)
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return 0;
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f_pos = 0;
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offset = 0;
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block = 0;
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while (f_pos < dir->i_size) {
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struct iso_directory_record *de;
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int de_len, match, i, dlen;
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char *dpnt;
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if (!bh) {
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bh = isofs_bread(dir, block);
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if (!bh)
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return 0;
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}
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de = (struct iso_directory_record *) (bh->b_data + offset);
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de_len = *(unsigned char *) de;
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if (!de_len) {
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brelse(bh);
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bh = NULL;
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f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
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block = f_pos >> bufbits;
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offset = 0;
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continue;
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}
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block_saved = bh->b_blocknr;
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offset_saved = offset;
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offset += de_len;
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f_pos += de_len;
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/* Make sure we have a full directory entry */
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if (offset >= bufsize) {
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int slop = bufsize - offset + de_len;
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memcpy(tmpde, de, slop);
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offset &= bufsize - 1;
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block++;
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brelse(bh);
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bh = NULL;
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if (offset) {
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bh = isofs_bread(dir, block);
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if (!bh)
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return 0;
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memcpy((void *) tmpde + slop, bh->b_data, offset);
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}
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de = tmpde;
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}
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dlen = de->name_len[0];
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dpnt = de->name;
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/* Basic sanity check, whether name doesn't exceed dir entry */
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if (de_len < dlen + sizeof(struct iso_directory_record)) {
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printk(KERN_NOTICE "iso9660: Corrupted directory entry"
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" in block %lu of inode %lu\n", block,
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dir->i_ino);
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return 0;
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}
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if (sbi->s_rock &&
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((i = get_rock_ridge_filename(de, tmpname, dir)))) {
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dlen = i; /* possibly -1 */
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dpnt = tmpname;
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#ifdef CONFIG_JOLIET
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} else if (sbi->s_joliet_level) {
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dlen = get_joliet_filename(de, tmpname, dir);
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dpnt = tmpname;
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#endif
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} else if (sbi->s_mapping == 'a') {
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dlen = get_acorn_filename(de, tmpname, dir);
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dpnt = tmpname;
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} else if (sbi->s_mapping == 'n') {
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dlen = isofs_name_translate(de, tmpname, dir);
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dpnt = tmpname;
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}
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/*
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* Skip hidden or associated files unless hide or showassoc,
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* respectively, is set
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*/
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match = 0;
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if (dlen > 0 &&
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(!sbi->s_hide ||
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(!(de->flags[-sbi->s_high_sierra] & 1))) &&
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(sbi->s_showassoc ||
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(!(de->flags[-sbi->s_high_sierra] & 4)))) {
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if (dpnt && (dlen > 1 || dpnt[0] > 1))
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match = (isofs_cmp(dentry, dpnt, dlen) == 0);
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}
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if (match) {
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isofs_normalize_block_and_offset(de,
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&block_saved,
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&offset_saved);
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*block_rv = block_saved;
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*offset_rv = offset_saved;
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brelse(bh);
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return 1;
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}
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}
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brelse(bh);
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return 0;
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}
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struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
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{
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int found;
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unsigned long uninitialized_var(block);
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unsigned long uninitialized_var(offset);
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struct inode *inode;
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struct page *page;
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page = alloc_page(GFP_USER);
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if (!page)
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return ERR_PTR(-ENOMEM);
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found = isofs_find_entry(dir, dentry,
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&block, &offset,
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page_address(page),
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1024 + page_address(page));
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__free_page(page);
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inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL;
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return d_splice_alias(inode, dentry);
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}
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