3 // Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
5 // This program is free software; you can redistribute it and/or modify
6 // it under the terms of the GNU General Public License as published by
7 // the Free Software Foundation; version 2 of the License.
9 // This program is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License
15 // along with this program; if not, write to the Free Software
16 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
33 Unify_unify(char const *src, struct stat const UNUSED *src_stat,
36 size_t l = strlen(dst);
37 char tmpfile[l + sizeof(";XXXXXX")];
42 // at first, set the ILI flags on 'src'
45 VC_IATTR_IUNLINK|VC_IATTR_IMMUTABLE,
46 VC_IATTR_IUNLINK|VC_IATTR_IMMUTABLE)==-1)
49 // check if 'dst' already exists
50 if (lstat(dst, &st)==0) {
51 // now, create a temporary filename
52 memcpy(tmpfile, dst, l);
53 memcpy(tmpfile+l, ";XXXXXX", 8);
54 fd = mkstemp(tmpfile);
62 // and rename the old file to this name
64 // NOTE: this rename() is race-free; when an attacker makes 'tmpfile' a
65 // directory, the operation would fail; when making it a symlink to a file
66 // or directory, the symlink but not the file/directory would be overridden
67 if (rename(dst, tmpfile)==-1) {
75 // now, link the src-file to dst
76 if (link(src, dst)==-1) {
80 if (tmpfile[0]!='\0' &&
81 rename(tmpfile, dst)==-1) {
82 perror("FATAL error in rename()");