1 /* Check non representable OFD locks regions in non-LFS mode for compat
2    mode (BZ #20251)
3    Copyright (C) 2018-2021 Free Software Foundation, Inc.
4 
5    This program is free software; you can redistribute it and/or
6    modify it under the terms of the GNU General Public License
7    as published by the Free Software Foundation; either version 2
8    of the License, or (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 <https://www.gnu.org/licenses/>.
17 */
18 
19 #include <unistd.h>
20 #include <fcntl.h>
21 #include <stdint.h>
22 #include <errno.h>
23 
24 #include <support/temp_file.h>
25 #include <support/check.h>
26 
27 #include <shlib-compat.h>
28 compat_symbol_reference (libc, fcntl, fcntl, GLIBC_2_0);
29 
30 static char *temp_filename;
31 static int temp_fd;
32 
33 static void
do_prepare(int argc,char ** argv)34 do_prepare (int argc, char **argv)
35 {
36   temp_fd = create_temp_file ("tst-ofdlocks-compat.", &temp_filename);
37   TEST_VERIFY_EXIT (temp_fd != -1);
38 }
39 
40 #define PREPARE do_prepare
41 
42 /* Linux between 4.13 and 4.15 return EOVERFLOW for LFS OFD locks usage
43    in compat mode (non-LFS ABI running on a LFS default kernel, such as
44    i386 on a x86_64 kernel or s390-32 on a s390-64 kernel) [1].  This is
45    a kernel issue because __NR_fcntl64 is the expected way to use OFD locks
46    (used on GLIBC for both fcntl and fcntl64).
47 
48    [1] https://sourceware.org/ml/libc-alpha/2018-07/msg00243.html  */
49 
50 static int
do_test(void)51 do_test (void)
52 {
53   /* The compat fcntl version for architectures which support non-LFS
54      operations does not wrap the flock OFD argument, so the struct is passed
55      unmodified to kernel.  It means no EOVERFLOW is returned, so operations
56      with LFS should not incur in failure.  */
57 
58   struct flock64 lck64 = {
59     .l_type   = F_WRLCK,
60     .l_whence = SEEK_SET,
61     .l_start  = (off64_t)INT32_MAX + 1024,
62     .l_len    = 1024,
63   };
64   int ret = fcntl (temp_fd, F_OFD_SETLKW, &lck64);
65   if (ret == -1 && errno == EINVAL)
66     /* OFD locks are only available on Linux 3.15.  */
67     FAIL_UNSUPPORTED ("fcntl (F_OFD_SETLKW) not supported");
68 
69   TEST_VERIFY_EXIT (ret == 0);
70 
71   /* Open file description locks placed through the same open file description
72      (either by same file descriptor or a duplicated one created by fork,
73      dup, fcntl F_DUPFD, etc.) overwrites then old lock.  To force a
74      conflicting lock combination, it creates a new file descriptor.  */
75   int fd = open64 (temp_filename, O_RDWR, 0666);
76   TEST_VERIFY_EXIT (fd != -1);
77 
78   struct flock64 lck = {
79     .l_type   = F_WRLCK,
80     .l_whence = SEEK_SET,
81     .l_start  = INT32_MAX - 1024,
82     .l_len    = 4 * 1024,
83   };
84   TEST_VERIFY (fcntl (fd, F_OFD_GETLK, &lck) == 0);
85 
86   return 0;
87 }
88 
89 #include <support/test-driver.c>
90