1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * QNX4 file system, Linux implementation. |
4 | * |
5 | * Version : 0.2.1 |
6 | * |
7 | * Using parts of the xiafs filesystem. |
8 | * |
9 | * History : |
10 | * |
11 | * 01-06-1998 by Richard Frowijn : first release. |
12 | * 21-06-1998 by Frank Denis : dcache support, fixed error codes. |
13 | * 04-07-1998 by Frank Denis : first step for rmdir/unlink. |
14 | */ |
15 | |
16 | #include <linux/buffer_head.h> |
17 | #include "qnx4.h" |
18 | |
19 | |
20 | /* |
21 | * check if the filename is correct. For some obscure reason, qnx writes a |
22 | * new file twice in the directory entry, first with all possible options at 0 |
23 | * and for a second time the way it is, they want us not to access the qnx |
24 | * filesystem when whe are using linux. |
25 | */ |
26 | static int qnx4_match(int len, const char *name, |
27 | struct buffer_head *bh, unsigned long *offset) |
28 | { |
29 | struct qnx4_inode_entry *de; |
30 | int namelen, thislen; |
31 | |
32 | if (bh == NULL) { |
33 | printk(KERN_WARNING "qnx4: matching unassigned buffer !\n" ); |
34 | return 0; |
35 | } |
36 | de = (struct qnx4_inode_entry *) (bh->b_data + *offset); |
37 | *offset += QNX4_DIR_ENTRY_SIZE; |
38 | if ((de->di_status & QNX4_FILE_LINK) != 0) { |
39 | namelen = QNX4_NAME_MAX; |
40 | } else { |
41 | namelen = QNX4_SHORT_NAME_MAX; |
42 | } |
43 | thislen = strlen( de->di_fname ); |
44 | if ( thislen > namelen ) |
45 | thislen = namelen; |
46 | if (len != thislen) { |
47 | return 0; |
48 | } |
49 | if (strncmp(name, de->di_fname, len) == 0) { |
50 | if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) { |
51 | return 1; |
52 | } |
53 | } |
54 | return 0; |
55 | } |
56 | |
57 | static struct buffer_head *qnx4_find_entry(int len, struct inode *dir, |
58 | const char *name, struct qnx4_inode_entry **res_dir, int *ino) |
59 | { |
60 | unsigned long block, offset, blkofs; |
61 | struct buffer_head *bh; |
62 | |
63 | *res_dir = NULL; |
64 | bh = NULL; |
65 | block = offset = blkofs = 0; |
66 | while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) { |
67 | if (!bh) { |
68 | block = qnx4_block_map(inode: dir, iblock: blkofs); |
69 | if (block) |
70 | bh = sb_bread(sb: dir->i_sb, block); |
71 | if (!bh) { |
72 | blkofs++; |
73 | continue; |
74 | } |
75 | } |
76 | *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset); |
77 | if (qnx4_match(len, name, bh, offset: &offset)) { |
78 | *ino = block * QNX4_INODES_PER_BLOCK + |
79 | (offset / QNX4_DIR_ENTRY_SIZE) - 1; |
80 | return bh; |
81 | } |
82 | if (offset < bh->b_size) { |
83 | continue; |
84 | } |
85 | brelse(bh); |
86 | bh = NULL; |
87 | offset = 0; |
88 | blkofs++; |
89 | } |
90 | brelse(bh); |
91 | *res_dir = NULL; |
92 | return NULL; |
93 | } |
94 | |
95 | struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
96 | { |
97 | int ino; |
98 | struct qnx4_inode_entry *de; |
99 | struct qnx4_link_info *lnk; |
100 | struct buffer_head *bh; |
101 | const char *name = dentry->d_name.name; |
102 | int len = dentry->d_name.len; |
103 | struct inode *foundinode = NULL; |
104 | |
105 | if (!(bh = qnx4_find_entry(len, dir, name, res_dir: &de, ino: &ino))) |
106 | goto out; |
107 | /* The entry is linked, let's get the real info */ |
108 | if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) { |
109 | lnk = (struct qnx4_link_info *) de; |
110 | ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) * |
111 | QNX4_INODES_PER_BLOCK + |
112 | lnk->dl_inode_ndx; |
113 | } |
114 | brelse(bh); |
115 | |
116 | foundinode = qnx4_iget(dir->i_sb, ino); |
117 | if (IS_ERR(ptr: foundinode)) |
118 | QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n" , |
119 | PTR_ERR(foundinode))); |
120 | out: |
121 | return d_splice_alias(foundinode, dentry); |
122 | } |
123 | |