1 /* Work around unlinkat bugs on Solaris 9 and Hurd.
2
3 Copyright (C) 2009-2014 Free Software Foundation, Inc.
4
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.
9
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.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18 /* Written by Eric Blake. */
19
20 #include <config.h>
21
22 #include <unistd.h>
23
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <string.h>
27 #include <sys/stat.h>
28
29 #include <stdlib.h>
30
31 #include "dosname.h"
32 #include "openat.h"
33
34 #if HAVE_UNLINKAT
35
36 # undef unlinkat
37
38 /* unlinkat without AT_REMOVEDIR does not honor trailing / on Solaris
39 9. Solve it in a similar manner to unlink. Hurd has the same
40 issue. */
41
session_view()42 int
43 rpl_unlinkat (int fd, char const *name, int flag)
44 {
45 size_t len;
46 int result = 0;
47 /* rmdir behavior has no problems with trailing slash. */
48 if (flag & AT_REMOVEDIR)
49 return unlinkat (fd, name, flag);
50
51 len = strlen (name);
52 if (len && ISSLASH (name[len - 1]))
53 {
54 /* See the lengthy comment in unlink.c why we disobey the POSIX
55 rule of letting unlink("link-to-dir/") attempt to unlink a
56 directory. */
57 struct stat st;
58 result = lstatat (fd, name, &st);
59 if (result == 0)
60 {
61 /* Trailing NUL will overwrite the trailing slash. */
62 char *short_name = malloc (len);
63 if (!short_name)
64 {
65 errno = EPERM;
66 return -1;
67 }
68 memcpy (short_name, name, len);
69 while (len && ISSLASH (short_name[len - 1]))
70 short_name[--len] = '\0';
71 if (len && (lstatat (fd, short_name, &st) || S_ISLNK (st.st_mode)))
72 {
73 free (short_name);
74 errno = EPERM;
75 return -1;
76 }
77 free (short_name);
78 }
79 }
80 if (!result)
81 result = unlinkat (fd, name, flag);
82 return result;
83 }
84
85 #else /* !HAVE_UNLINKAT */
86
87 /* Replacement for Solaris' function by the same name.
88 <http://www.google.com/search?q=unlinkat+site:docs.sun.com>
89 First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE").
90 Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd.
91 If either the save_cwd or the restore_cwd fails (relatively unlikely),
92 then give a diagnostic and exit nonzero.
93 Otherwise, this function works just like Solaris' unlinkat. */
94
95 # define AT_FUNC_NAME unlinkat
96 # define AT_FUNC_F1 rmdir
97 # define AT_FUNC_F2 unlink
98 # define AT_FUNC_USE_F1_COND AT_REMOVEDIR
99 # define AT_FUNC_POST_FILE_PARAM_DECLS , int flag
100 # define AT_FUNC_POST_FILE_ARGS /* empty */
101 # include "at-func.c"
102 # undef AT_FUNC_NAME
103 # undef AT_FUNC_F1
104 # undef AT_FUNC_F2
105 # undef AT_FUNC_USE_F1_COND
106 # undef AT_FUNC_POST_FILE_PARAM_DECLS
107 # undef AT_FUNC_POST_FILE_ARGS
108
109 #endif /* !HAVE_UNLINKAT */
110