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174 lines
4.2 KiB
174 lines
4.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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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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brelse(bh); |
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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 block; |
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unsigned long 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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