1 /* Work around unlink bugs.
3 Copyright (C) 2009-2017 Free Software Foundation, Inc.
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; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
32 Return 0 if successful, -1 if not. */
35 rpl_unlink (char const *name
)
37 /* Work around Solaris 9 bug where unlink("file/") succeeds. */
38 size_t len
= strlen (name
);
40 if (len
&& ISSLASH (name
[len
- 1]))
42 /* We can't unlink(2) something if it doesn't exist. If it does
43 exist, then it resolved to a directory, due to the trailing
44 slash, and POSIX requires that the unlink attempt to remove
45 that directory (which would leave the symlink dangling).
46 Unfortunately, Solaris 9 is one of the platforms where the
47 root user can unlink directories, and we don't want to
48 cripple this behavior on real directories, even if it is
49 seldom needed (at any rate, it's nicer to let coreutils'
50 unlink(1) give the correct errno for non-root users). But we
51 don't know whether name was an actual directory, or a symlink
52 to a directory; and due to the bug of ignoring trailing
53 slash, Solaris 9 would end up successfully unlinking the
54 symlink instead of the directory. Technically, we could use
55 realpath to find the canonical directory name to attempt
56 deletion on. But that is a lot of work for a corner case; so
57 we instead just use an lstat on the shortened name, and
58 reject symlinks with trailing slashes. The root user of
59 unlink(1) will just have to live with the rule that they
60 can't delete a directory via a symlink. */
62 result
= lstat (name
, &st
);
65 /* Trailing NUL will overwrite the trailing slash. */
66 char *short_name
= malloc (len
);
72 memcpy (short_name
, name
, len
);
73 while (len
&& ISSLASH (short_name
[len
- 1]))
74 short_name
[--len
] = '\0';
75 if (len
&& (lstat (short_name
, &st
) || S_ISLNK (st
.st_mode
)))
87 if (len
>= 2 && name
[len
- 1] == '.' && name
[len
- 2] == '.'
88 && (len
== 2 || ISSLASH (name
[len
- 3])))
90 errno
= EISDIR
; /* could also use EPERM */
94 result
= unlink (name
);