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/*
* link.c --- create links in a ext2fs directory
*
* Copyright (C) 1993, 1994 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if EXT2_FLAT_INCLUDES
#include "ext2_fs.h"
#else
#include <linux/ext2_fs.h>
#endif
#include "ext2fs.h"
struct link_struct {
const char *name;
int namelen;
ino_t inode;
int flags;
int done;
};
static int link_proc(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *priv_data)
{
struct link_struct *ls = (struct link_struct *) priv_data;
struct ext2_dir_entry *next;
int rec_len;
int ret = 0;
rec_len = EXT2_DIR_REC_LEN(ls->namelen);
/*
* See if the following directory entry (if any) is unused;
* if so, absorb it into this one.
*/
next = (struct ext2_dir_entry *) (buf + offset + dirent->rec_len);
if ((offset + dirent->rec_len < blocksize - 8) &&
(next->inode == 0) &&
(offset + dirent->rec_len + next->rec_len <= blocksize)) {
dirent->rec_len += next->rec_len;
ret = DIRENT_CHANGED;
}
/*
* If the directory entry is used, see if we can split the
* directory entry to make room for the new name. If so,
* truncate it and return.
*/
if (dirent->inode) {
if (dirent->rec_len < (EXT2_DIR_REC_LEN(dirent->name_len) +
rec_len))
return ret;
rec_len = dirent->rec_len - EXT2_DIR_REC_LEN(dirent->name_len);
dirent->rec_len = EXT2_DIR_REC_LEN(dirent->name_len);
next = (struct ext2_dir_entry *) (buf + offset +
dirent->rec_len);
next->inode = 0;
next->name_len = 0;
next->rec_len = rec_len;
return DIRENT_CHANGED;
}
/*
* If we get this far, then the directory entry is not used.
* See if we can fit the request entry in. If so, do it.
*/
if (dirent->rec_len < rec_len)
return ret;
dirent->inode = ls->inode;
dirent->name_len = ls->namelen;
strncpy(dirent->name, ls->name, ls->namelen);
ls->done++;
return DIRENT_ABORT|DIRENT_CHANGED;
}
#ifdef __TURBOC__
#pragma argsused
#endif
errcode_t ext2fs_link(ext2_filsys fs, ino_t dir, const char *name, ino_t ino,
int flags)
{
errcode_t retval;
struct link_struct ls;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (!(fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
ls.name = name;
ls.namelen = name ? strlen(name) : 0;
ls.inode = ino;
ls.flags = 0;
ls.done = 0;
retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY,
0, link_proc, &ls);
if (retval)
return retval;
return (ls.done) ? 0 : EXT2_ET_DIR_NO_SPACE;
}
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