| | 1 | // SPDX-License-Identifier: GPL-2.0 |
| | 2 | /* |
| | 3 | * linux/fs/isofs/namei.c |
| | 4 | * |
| | 5 | * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. |
| | 6 | * |
| | 7 | * (C) 1991 Linus Torvalds - minix filesystem |
| | 8 | */ |
| | 9 | |
| | 10 | #include <linux/gfp.h> |
| | 11 | #include "isofs.h" |
| | 12 | |
| | 13 | /* |
| | 14 | * ok, we cannot use strncmp, as the name is not in our data space. |
| | 15 | * Thus we'll have to use isofs_match. No big problem. Match also makes |
| | 16 | * some sanity tests. |
| | 17 | */ |
| | 18 | static int |
| | 19 | isofs_cmp(struct dentry *dentry, const char *compare, int dlen) |
| | 20 | { |
| | 21 | struct qstr qstr; |
| | 22 | qstr.name = compare; |
| | 23 | qstr.len = dlen; |
| | 24 | if (likely(!dentry->d_op)) |
| | 25 | return dentry->d_name.len != dlen || memcmp(dentry->d_name.name, compare, dlen); |
| | 26 | return dentry->d_op->d_compare(NULL, dentry->d_name.len, dentry->d_name.name, &qstr); |
| | 27 | } |
| | 28 | |
| | 29 | /* |
| | 30 | * isofs_find_entry() |
| | 31 | * |
| | 32 | * finds an entry in the specified directory with the wanted name. It |
| | 33 | * returns the inode number of the found entry, or 0 on error. |
| | 34 | */ |
| | 35 | static unsigned long |
| | 36 | isofs_find_entry(struct inode *dir, struct dentry *dentry, |
| | 37 | unsigned long *block_rv, unsigned long *offset_rv, |
| | 38 | char *tmpname, struct iso_directory_record *tmpde) |
| | 39 | { |
| | 40 | unsigned long bufsize = ISOFS_BUFFER_SIZE(dir); |
| | 41 | unsigned char bufbits = ISOFS_BUFFER_BITS(dir); |
| | 42 | unsigned long block, f_pos, offset, block_saved, offset_saved; |
| | 43 | struct buffer_head *bh = NULL; |
| | 44 | struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb); |
| | 45 | |
| | 46 | if (!ISOFS_I(dir)->i_first_extent) |
| | 47 | return 0; |
| | 48 | |
| | 49 | f_pos = 0; |
| | 50 | offset = 0; |
| | 51 | block = 0; |
| | 52 | |
| | 53 | while (f_pos < dir->i_size) { |
| | 54 | struct iso_directory_record *de; |
| | 55 | int de_len, match, i, dlen; |
| | 56 | char *dpnt; |
| | 57 | |
| | 58 | if (!bh) { |
| | 59 | bh = isofs_bread(dir, block); |
| | 60 | if (!bh) |
| | 61 | return 0; |
| | 62 | } |
| | 63 | |
| | 64 | de = (struct iso_directory_record *) (bh->b_data + offset); |
| | 65 | |
| | 66 | de_len = *(unsigned char *) de; |
| | 67 | if (!de_len) { |
| | 68 | brelse(bh); |
| | 69 | bh = NULL; |
| | 70 | f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); |
| | 71 | block = f_pos >> bufbits; |
| | 72 | offset = 0; |
| | 73 | continue; |
| | 74 | } |
| | 75 | |
| | 76 | block_saved = bh->b_blocknr; |
| | 77 | offset_saved = offset; |
| | 78 | offset += de_len; |
| | 79 | f_pos += de_len; |
| | 80 | |
| | 81 | /* Make sure we have a full directory entry */ |
| | 82 | if (offset >= bufsize) { |
| | 83 | int slop = bufsize - offset + de_len; |
| | 84 | memcpy(tmpde, de, slop); |
| | 85 | offset &= bufsize - 1; |
| | 86 | block++; |
| | 87 | brelse(bh); |
| | 88 | bh = NULL; |
| | 89 | if (offset) { |
| | 90 | bh = isofs_bread(dir, block); |
| | 91 | if (!bh) |
| | 92 | return 0; |
| | 93 | memcpy((void *) tmpde + slop, bh->b_data, offset); |
| | 94 | } |
| | 95 | de = tmpde; |
| | 96 | } |
| | 97 | |
| | 98 | dlen = de->name_len[0]; |
| | 99 | dpnt = de->name; |
| | 100 | /* Basic sanity check, whether name doesn't exceed dir entry */ |
| | 101 | if (de_len < dlen + sizeof(struct iso_directory_record)) { |
| | 102 | printk(KERN_NOTICE "iso9660: Corrupted directory entry" |
| | 103 | " in block %lu of inode %lu\n", block, |
| | 104 | dir->i_ino); |
| | 105 | return 0; |
| | 106 | } |
| | 107 | |
| | 108 | if (sbi->s_rock && |
| | 109 | ((i = get_rock_ridge_filename(de, tmpname, dir)))) { |
| | 110 | dlen = i; /* possibly -1 */ |
| | 111 | dpnt = tmpname; |
| | 112 | #ifdef CONFIG_JOLIET |
| | 113 | } else if (sbi->s_joliet_level) { |
| | 114 | dlen = get_joliet_filename(de, tmpname, dir); |
| | 115 | dpnt = tmpname; |
| | 116 | #endif |
| | 117 | } else if (sbi->s_mapping == 'a') { |
| | 118 | dlen = get_acorn_filename(de, tmpname, dir); |
| | 119 | dpnt = tmpname; |
| | 120 | } else if (sbi->s_mapping == 'n') { |
| | 121 | dlen = isofs_name_translate(de, tmpname, dir); |
| | 122 | dpnt = tmpname; |
| | 123 | } |
| | 124 | |
| | 125 | /* |
| | 126 | * Skip hidden or associated files unless hide or showassoc, |
| | 127 | * respectively, is set |
| | 128 | */ |
| | 129 | match = 0; |
| | 130 | if (dlen > 0 && |
| | 131 | (!sbi->s_hide || |
| | 132 | (!(de->flags[-sbi->s_high_sierra] & 1))) && |
| | 133 | (sbi->s_showassoc || |
| | 134 | (!(de->flags[-sbi->s_high_sierra] & 4)))) { |
| | 135 | if (dpnt && (dlen > 1 || dpnt[0] > 1)) |
| | 136 | match = (isofs_cmp(dentry, dpnt, dlen) == 0); |
| | 137 | } |
| | 138 | if (match) { |
| | 139 | isofs_normalize_block_and_offset(de, |
| | 140 | &block_saved, |
| | 141 | &offset_saved); |
| | 142 | *block_rv = block_saved; |
| | 143 | *offset_rv = offset_saved; |
| | 144 | brelse(bh); |
| | 145 | return 1; |
| | 146 | } |
| | 147 | } |
| | 148 | brelse(bh); |
| | 149 | return 0; |
| | 150 | } |
| | 151 | |
| | 152 | struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| | 153 | { |
| | 154 | int found; |
| | 155 | unsigned long uninitialized_var(block); |
| | 156 | unsigned long uninitialized_var(offset); |
| | 157 | struct inode *inode; |
| | 158 | struct page *page; |
| | 159 | |
| | 160 | page = alloc_page(GFP_USER); |
| | 161 | if (!page) |
| | 162 | return ERR_PTR(-ENOMEM); |
| | 163 | |
| | 164 | found = isofs_find_entry(dir, dentry, |
| | 165 | &block, &offset, |
| | 166 | page_address(page), |
| | 167 | 1024 + page_address(page)); |
| | 168 | __free_page(page); |
| | 169 | |
| | 170 | inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL; |
| | 171 | |
| | 172 | return d_splice_alias(inode, dentry); |
| | 173 | } |
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