1 /* Tests for support_open_dev_null_range.
2 Copyright (C) 2021-2023 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 <dirent.h>
21 #include <fcntl.h>
22 #include <limits.h>
23 #include <support/check.h>
24 #include <support/support.h>
25 #include <support/xunistd.h>
26 #include <sys/resource.h>
27 #include <stdlib.h>
28
29 #ifndef PATH_MAX
30 # define PATH_MAX 1024
31 #endif
32
33 #include <stdio.h>
34
35 static void
36 check_path (int fd)
37 {
38 char *proc_fd_path = xasprintf ("/proc/self/fd/%d", fd);
39 char file_path[PATH_MAX];
40 ssize_t file_path_length
41 = readlink (proc_fd_path, file_path, sizeof (file_path));
42 if (file_path_length < 0)
43 FAIL_EXIT1 ("readlink (%s, %p, %zu)", proc_fd_path, file_path,
44 sizeof (file_path));
45
46 free (proc_fd_path);
47 file_path[file_path_length] = '\0';
48 TEST_COMPARE_STRING (file_path, "/dev/null");
49 }
50
51 static int
52 number_of_opened_files (void)
53 {
54 DIR *fds = opendir ("/proc/self/fd");
55 if (fds == NULL)
56 FAIL_EXIT1 ("opendir (\"/proc/self/fd\"): %m");
57
58 int r = 0;
59 while (true)
60 {
61 errno = 0;
62 struct dirent64 *e = readdir64 (fds);
63 if (e == NULL)
64 {
65 if (errno != 0)
66 FAIL_EXIT1 ("readdir: %m");
67 break;
68 }
69
70 if (e->d_name[0] == '.')
71 continue;
72
73 char *endptr;
74 long int fd = strtol (e->d_name, &endptr, 10);
75 if (*endptr != '\0' || fd < 0 || fd > INT_MAX)
76 FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s",
77 e->d_name);
78
79 /* Skip the descriptor which is used to enumerate the
80 descriptors. */
81 if (fd == dirfd (fds))
82 continue;
83
84 r = r + 1;
85 }
86
87 closedir (fds);
88
89 return r;
90 }
91
92 static int
93 do_test (void)
94 {
95 const int nfds1 = 8;
96 int lowfd = support_open_dev_null_range (nfds1, O_RDONLY, 0600);
97 for (int i = 0; i < nfds1; i++)
98 {
99 TEST_VERIFY (fcntl (lowfd + i, F_GETFL) > -1);
100 check_path (lowfd + i);
101 }
102
103 /* create some gaps. */
104 xclose (lowfd + 1);
105 xclose (lowfd + 5);
106 xclose (lowfd + 6);
107
108 const int nfds2 = 16;
109 int lowfd2 = support_open_dev_null_range (nfds2, O_RDONLY, 0600);
110 for (int i = 0; i < nfds2; i++)
111 {
112 TEST_VERIFY (fcntl (lowfd2 + i, F_GETFL) > -1);
113 check_path (lowfd2 + i);
114 }
115
116 /* Decrease the maximum number of files. */
117 {
118 struct rlimit rl;
119 if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
120 FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
121
122 rl.rlim_cur = number_of_opened_files ();
123
124 if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
125 FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
126 }
127
128 const int nfds3 = 16;
129 int lowfd3 = support_open_dev_null_range (nfds3, O_RDONLY, 0600);
130 for (int i = 0; i < nfds3; i++)
131 {
132 TEST_VERIFY (fcntl (lowfd3 + i, F_GETFL) > -1);
133 check_path (lowfd3 + i);
134 }
135
136 /* create a lot of gaps to trigger the range extension. */
137 xclose (lowfd3 + 1);
138 xclose (lowfd3 + 3);
139 xclose (lowfd3 + 5);
140 xclose (lowfd3 + 7);
141 xclose (lowfd3 + 9);
142 xclose (lowfd3 + 11);
143 xclose (lowfd3 + 13);
144
145 const int nfds4 = 16;
146 int lowfd4 = support_open_dev_null_range (nfds4, O_RDONLY, 0600);
147 for (int i = 0; i < nfds4; i++)
148 {
149 TEST_VERIFY (fcntl (lowfd4 + i, F_GETFL) > -1);
150 check_path (lowfd4 + i);
151 }
152
153 return 0;
154 }
155
156 #include <support/test-driver.c>