xref: /openbmc/linux/fs/efs/namei.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * namei.c
3  *
4  * Copyright (c) 1999 Al Smith
5  *
6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
7  */
8 
9 #include <linux/buffer_head.h>
10 #include <linux/string.h>
11 #include <linux/efs_fs.h>
12 #include <linux/smp_lock.h>
13 
14 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
15 	struct buffer_head *bh;
16 
17 	int			slot, namelen;
18 	char			*nameptr;
19 	struct efs_dir		*dirblock;
20 	struct efs_dentry	*dirslot;
21 	efs_ino_t		inodenum;
22 	efs_block_t		block;
23 
24 	if (inode->i_size & (EFS_DIRBSIZE-1))
25 		printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");
26 
27 	for(block = 0; block < inode->i_blocks; block++) {
28 
29 		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
30 		if (!bh) {
31 			printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
32 			return 0;
33 		}
34 
35 		dirblock = (struct efs_dir *) bh->b_data;
36 
37 		if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
38 			printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
39 			brelse(bh);
40 			return(0);
41 		}
42 
43 		for(slot = 0; slot < dirblock->slots; slot++) {
44 			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
45 
46 			namelen  = dirslot->namelen;
47 			nameptr  = dirslot->name;
48 
49 			if ((namelen == len) && (!memcmp(name, nameptr, len))) {
50 				inodenum = be32_to_cpu(dirslot->inode);
51 				brelse(bh);
52 				return(inodenum);
53 			}
54 		}
55 		brelse(bh);
56 	}
57 	return(0);
58 }
59 
60 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
61 	efs_ino_t inodenum;
62 	struct inode * inode = NULL;
63 
64 	lock_kernel();
65 	inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
66 	if (inodenum) {
67 		if (!(inode = iget(dir->i_sb, inodenum))) {
68 			unlock_kernel();
69 			return ERR_PTR(-EACCES);
70 		}
71 	}
72 	unlock_kernel();
73 
74 	d_add(dentry, inode);
75 	return NULL;
76 }
77 
78 struct dentry *efs_get_parent(struct dentry *child)
79 {
80 	struct dentry *parent;
81 	struct inode *inode;
82 	efs_ino_t ino;
83 	int error;
84 
85 	lock_kernel();
86 
87 	error = -ENOENT;
88 	ino = efs_find_entry(child->d_inode, "..", 2);
89 	if (!ino)
90 		goto fail;
91 
92 	error = -EACCES;
93 	inode = iget(child->d_inode->i_sb, ino);
94 	if (!inode)
95 		goto fail;
96 
97 	error = -ENOMEM;
98 	parent = d_alloc_anon(inode);
99 	if (!parent)
100 		goto fail_iput;
101 
102 	unlock_kernel();
103 	return parent;
104 
105  fail_iput:
106 	iput(inode);
107  fail:
108 	unlock_kernel();
109 	return ERR_PTR(error);
110 }
111