source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/link.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 3.1 KB
Line 
1/*
2 * link.c --- create links in a ext2fs directory
3 *
4 * Copyright (C) 1993, 1994 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#include <string.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17
18#include "ext2_fs.h"
19#include "ext2fs.h"
20
21struct link_struct  {
22    const char  *name;
23    int     namelen;
24    ext2_ino_t  inode;
25    int     flags;
26    int     done;
27    struct ext2_super_block *sb;
28};
29
30static int link_proc(struct ext2_dir_entry *dirent,
31             int    offset,
32             int    blocksize,
33             char   *buf,
34             void   *priv_data)
35{
36    struct link_struct *ls = (struct link_struct *) priv_data;
37    struct ext2_dir_entry *next;
38    int rec_len, min_rec_len;
39    int ret = 0;
40
41    rec_len = EXT2_DIR_REC_LEN(ls->namelen);
42
43    /*
44     * See if the following directory entry (if any) is unused;
45     * if so, absorb it into this one.
46     */
47    next = (struct ext2_dir_entry *) (buf + offset + dirent->rec_len);
48    if ((offset + dirent->rec_len < blocksize - 8) &&
49        (next->inode == 0) &&
50        (offset + dirent->rec_len + next->rec_len <= blocksize)) {
51        dirent->rec_len += next->rec_len;
52        ret = DIRENT_CHANGED;
53    }
54
55    /*
56     * If the directory entry is used, see if we can split the
57     * directory entry to make room for the new name.  If so,
58     * truncate it and return.
59     */
60    if (dirent->inode) {
61        min_rec_len = EXT2_DIR_REC_LEN(dirent->name_len & 0xFF);
62        if (dirent->rec_len < (min_rec_len + rec_len))
63            return ret;
64        rec_len = dirent->rec_len - min_rec_len;
65        dirent->rec_len = min_rec_len;
66        next = (struct ext2_dir_entry *) (buf + offset +
67                          dirent->rec_len);
68        next->inode = 0;
69        next->name_len = 0;
70        next->rec_len = rec_len;
71        return DIRENT_CHANGED;
72    }
73
74    /*
75     * If we get this far, then the directory entry is not used.
76     * See if we can fit the request entry in.  If so, do it.
77     */
78    if (dirent->rec_len < rec_len)
79        return ret;
80    dirent->inode = ls->inode;
81    dirent->name_len = ls->namelen;
82    strncpy(dirent->name, ls->name, ls->namelen);
83    if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE)
84        dirent->name_len |= (ls->flags & 0x7) << 8;
85
86    ls->done++;
87    return DIRENT_ABORT|DIRENT_CHANGED;
88}
89
90/*
91 * Note: the low 3 bits of the flags field are used as the directory
92 * entry filetype.
93 */
94#ifdef __TURBOC__
95# pragma argsused
96#endif
97errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name,
98              ext2_ino_t ino, int flags)
99{
100    errcode_t       retval;
101    struct link_struct  ls;
102    struct ext2_inode   inode;
103
104    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
105
106    if (!(fs->flags & EXT2_FLAG_RW))
107        return EXT2_ET_RO_FILSYS;
108
109    ls.name = name;
110    ls.namelen = name ? strlen(name) : 0;
111    ls.inode = ino;
112    ls.flags = flags;
113    ls.done = 0;
114    ls.sb = fs->super;
115
116    retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY,
117                    0, link_proc, &ls);
118    if (retval)
119        return retval;
120
121    if (!ls.done)
122        return EXT2_ET_DIR_NO_SPACE;
123
124    if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0)
125        return retval;
126
127    if (inode.i_flags & EXT2_INDEX_FL) {
128        inode.i_flags &= ~EXT2_INDEX_FL;
129        if ((retval = ext2fs_write_inode(fs, dir, &inode)) != 0)
130            return retval;
131    }
132
133    return 0;
134}
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