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