1 /* Basic test coverage for updwtmpx.
2    Copyright (C) 2019-2021 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public License as
7    published by the Free Software Foundation; either version 2.1 of the
8    License, or (at your option) any later version.
9 
10    The GNU C Library 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 GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; see the file COPYING.LIB.  If
17    not, see <https://www.gnu.org/licenses/>.  */
18 
19 /* This program runs a series of tests.  Each one calls updwtmpx
20    twice, to write two records, optionally with misalignment in the
21    file, and reads back the results.  */
22 
23 #include <errno.h>
24 #include <stdlib.h>
25 #include <support/check.h>
26 #include <support/descriptors.h>
27 #include <support/support.h>
28 #include <support/temp_file.h>
29 #include <support/test-driver.h>
30 #include <support/xunistd.h>
31 #include <unistd.h>
32 #include <utmpx.h>
33 
34 static int
do_test(void)35 do_test (void)
36 {
37   /* Two entries filled with an arbitrary bit pattern.  */
38   struct utmpx entries[2];
39   unsigned char pad;
40   {
41     unsigned char *p = (unsigned char *) &entries[0];
42     for (size_t i = 0; i < sizeof (entries); ++i)
43       {
44         p[i] = i;
45       }
46     /* Make sure that the first and second entry and the padding are
47        different.  */
48     p[sizeof (struct utmpx)] = p[0] + 1;
49     pad = p[0] + 2;
50   }
51 
52   char *path;
53   int fd = create_temp_file ("tst-updwtmpx-", &path);
54 
55   /* Used to check that updwtmpx does not leave an open file
56      descriptor around.  */
57   struct support_descriptors *descriptors = support_descriptors_list ();
58 
59   /* updwtmpx is expected to remove misalignment.  Optionally insert
60      one byte of misalignment at the start and in the middle (after
61      the first entry).  */
62   for (int misaligned_start = 0; misaligned_start < 2; ++misaligned_start)
63     for (int misaligned_middle = 0; misaligned_middle < 2; ++misaligned_middle)
64       {
65         if (test_verbose > 0)
66           printf ("info: misaligned_start=%d misaligned_middle=%d\n",
67                   misaligned_start, misaligned_middle);
68 
69         xftruncate (fd, 0);
70         TEST_COMPARE (pwrite64 (fd, &pad, misaligned_start, 0),
71                       misaligned_start);
72 
73         /* Write first entry and check it.  */
74         errno = 0;
75         updwtmpx (path, &entries[0]);
76         TEST_COMPARE (errno, 0);
77         support_descriptors_check (descriptors);
78         TEST_COMPARE (xlseek (fd, 0, SEEK_END), sizeof (struct utmpx));
79         struct utmpx buffer;
80         TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), 0),
81                       sizeof (buffer));
82         TEST_COMPARE_BLOB (&entries[0], sizeof (entries[0]),
83                            &buffer, sizeof (buffer));
84 
85         /* Middle mis-alignmet.  */
86         TEST_COMPARE (pwrite64 (fd, &pad, misaligned_middle,
87                                 sizeof (struct utmpx)), misaligned_middle);
88 
89         /* Write second entry and check both entries.  */
90         errno = 0;
91         updwtmpx (path, &entries[1]);
92         TEST_COMPARE (errno, 0);
93         support_descriptors_check (descriptors);
94         TEST_COMPARE (xlseek (fd, 0, SEEK_END), 2 * sizeof (struct utmpx));
95         TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), 0),
96                       sizeof (buffer));
97         TEST_COMPARE_BLOB (&entries[0], sizeof (entries[0]),
98                            &buffer, sizeof (buffer));
99         TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), sizeof (buffer)),
100                       sizeof (buffer));
101         TEST_COMPARE_BLOB (&entries[1], sizeof (entries[1]),
102                            &buffer, sizeof (buffer));
103       }
104 
105   support_descriptors_free (descriptors);
106   free (path);
107   xclose (fd);
108 
109   return 0;
110 }
111 
112 #include <support/test-driver.c>
113