1 /* Smoke test for the closefrom.
2 Copyright (C) 2021-2022 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
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <sys/resource.h>
22 #include <unistd.h>
23
24 #include <support/check.h>
25 #include <support/descriptors.h>
26 #include <support/xunistd.h>
27 #include <support/support.h>
28
29 #include <array_length.h>
30
31 #define NFDS 100
32
33 static int
closefrom_test(void)34 closefrom_test (void)
35 {
36 struct support_descriptors *descrs = support_descriptors_list ();
37
38 int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);
39
40 const int maximum_fd = lowfd + NFDS - 1;
41 const int half_fd = lowfd + NFDS / 2;
42 const int gap = lowfd + NFDS / 4;
43
44 /* Close half of the descriptors and check result. */
45 closefrom (half_fd);
46
47 for (int i = half_fd; i <= maximum_fd; i++)
48 {
49 TEST_COMPARE (fcntl (i, F_GETFL), -1);
50 TEST_COMPARE (errno, EBADF);
51 }
52 for (int i = lowfd; i < half_fd; i++)
53 TEST_VERIFY (fcntl (i, F_GETFL) > -1);
54
55 /* Create some gaps, close up to a threshold, and check result. */
56 xclose (lowfd + 35);
57 xclose (lowfd + 38);
58 xclose (lowfd + 42);
59 xclose (lowfd + 46);
60
61 /* Close half of the descriptors and check result. */
62 closefrom (gap);
63 for (int i = gap + 1; i < maximum_fd; i++)
64 {
65 TEST_COMPARE (fcntl (i, F_GETFL), -1);
66 TEST_COMPARE (errno, EBADF);
67 }
68 for (int i = lowfd; i < gap; i++)
69 TEST_VERIFY (fcntl (i, F_GETFL) > -1);
70
71 /* Close the remmaining but the last one. */
72 closefrom (lowfd + 1);
73 for (int i = lowfd + 1; i <= maximum_fd; i++)
74 {
75 TEST_COMPARE (fcntl (i, F_GETFL), -1);
76 TEST_COMPARE (errno, EBADF);
77 }
78 TEST_VERIFY (fcntl (lowfd, F_GETFL) > -1);
79
80 /* Close the last one. */
81 closefrom (lowfd);
82 TEST_COMPARE (fcntl (lowfd, F_GETFL), -1);
83 TEST_COMPARE (errno, EBADF);
84
85 /* Double check by check the /proc. */
86 support_descriptors_check (descrs);
87 support_descriptors_free (descrs);
88
89 return 0;
90 }
91
92 /* Check if closefrom works even when no new file descriptors can be
93 created. */
94 static int
closefrom_test_file_desc_limit(void)95 closefrom_test_file_desc_limit (void)
96 {
97 int max_fd = NFDS;
98 {
99 struct rlimit rl;
100 if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
101 FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
102
103 max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
104 rl.rlim_cur = max_fd;
105
106 if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
107 FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
108 }
109
110 /* Exhauste the file descriptor limit. */
111 int lowfd = xopen ("/dev/null", O_RDONLY, 0600);
112 for (;;)
113 {
114 int fd = open ("/dev/null", O_RDONLY, 0600);
115 if (fd == -1)
116 {
117 if (errno != EMFILE)
118 FAIL_EXIT1 ("open: %m");
119 break;
120 }
121 TEST_VERIFY_EXIT (fd < max_fd);
122 }
123
124 closefrom (lowfd);
125 for (int i = lowfd; i < NFDS; i++)
126 {
127 TEST_COMPARE (fcntl (i, F_GETFL), -1);
128 TEST_COMPARE (errno, EBADF);
129 }
130
131 return 0;
132 }
133
134 static int
do_test(void)135 do_test (void)
136 {
137 closefrom_test ();
138 closefrom_test_file_desc_limit ();
139
140 return 0;
141 }
142
143 #include <support/test-driver.c>
144