98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
|
/* Work around unlink bugs.
|
||
|
|
|
||
|
|
Copyright (C) 2009-2020 Free Software Foundation, Inc.
|
||
|
|
|
||
|
|
This program is free software: you can redistribute it and/or modify
|
||
|
|
it under the terms of the GNU General Public License as published by
|
||
|
|
the Free Software Foundation; either version 3 of the License, or
|
||
|
|
(at your option) any later version.
|
||
|
|
|
||
|
|
This program is distributed in the hope that it will be useful,
|
||
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
GNU General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License
|
||
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
||
|
|
|
||
|
|
#include <config.h>
|
||
|
|
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
#include <errno.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <sys/stat.h>
|
||
|
|
|
||
|
|
#include "dosname.h"
|
||
|
|
|
||
|
|
#undef unlink
|
||
|
|
|
||
|
|
/* Remove file NAME.
|
||
|
|
Return 0 if successful, -1 if not. */
|
||
|
|
|
||
|
|
int
|
||
|
|
rpl_unlink (char const *name)
|
||
|
|
{
|
||
|
|
/* Work around Solaris 9 bug where unlink("file/") succeeds. */
|
||
|
|
size_t len = strlen (name);
|
||
|
|
int result = 0;
|
||
|
|
if (len && ISSLASH (name[len - 1]))
|
||
|
|
{
|
||
|
|
/* We can't unlink(2) something if it doesn't exist. If it does
|
||
|
|
exist, then it resolved to a directory, due to the trailing
|
||
|
|
slash, and POSIX requires that the unlink attempt to remove
|
||
|
|
that directory (which would leave the symlink dangling).
|
||
|
|
Unfortunately, Solaris 9 is one of the platforms where the
|
||
|
|
root user can unlink directories, and we don't want to
|
||
|
|
cripple this behavior on real directories, even if it is
|
||
|
|
seldom needed (at any rate, it's nicer to let coreutils'
|
||
|
|
unlink(1) give the correct errno for non-root users). But we
|
||
|
|
don't know whether name was an actual directory, or a symlink
|
||
|
|
to a directory; and due to the bug of ignoring trailing
|
||
|
|
slash, Solaris 9 would end up successfully unlinking the
|
||
|
|
symlink instead of the directory. Technically, we could use
|
||
|
|
realpath to find the canonical directory name to attempt
|
||
|
|
deletion on. But that is a lot of work for a corner case; so
|
||
|
|
we instead just use an lstat on the shortened name, and
|
||
|
|
reject symlinks with trailing slashes. The root user of
|
||
|
|
unlink(1) will just have to live with the rule that they
|
||
|
|
can't delete a directory via a symlink. */
|
||
|
|
struct stat st;
|
||
|
|
result = lstat (name, &st);
|
||
|
|
if (result == 0)
|
||
|
|
{
|
||
|
|
/* Trailing NUL will overwrite the trailing slash. */
|
||
|
|
char *short_name = malloc (len);
|
||
|
|
if (!short_name)
|
||
|
|
{
|
||
|
|
errno = EPERM;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
memcpy (short_name, name, len);
|
||
|
|
while (len && ISSLASH (short_name[len - 1]))
|
||
|
|
short_name[--len] = '\0';
|
||
|
|
if (len && (lstat (short_name, &st) || S_ISLNK (st.st_mode)))
|
||
|
|
{
|
||
|
|
free (short_name);
|
||
|
|
errno = EPERM;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
free (short_name);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (!result)
|
||
|
|
{
|
||
|
|
#if UNLINK_PARENT_BUG
|
||
|
|
if (len >= 2 && name[len - 1] == '.' && name[len - 2] == '.'
|
||
|
|
&& (len == 2 || ISSLASH (name[len - 3])))
|
||
|
|
{
|
||
|
|
errno = EISDIR; /* could also use EPERM */
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
result = unlink (name);
|
||
|
|
}
|
||
|
|
return result;
|
||
|
|
}
|