xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Tests for fork. |
| 2 | Copyright (C) 2000-2016 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000. |
| 5 | |
| 6 | The GNU C Library is free software; you can redistribute it and/or |
| 7 | modify it under the terms of the GNU Lesser General Public |
| 8 | License as published by the Free Software Foundation; either |
| 9 | version 2.1 of the License, or (at your option) any later version. |
| 10 | |
| 11 | The GNU C Library is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <error.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <string.h> |
| 24 | #include <unistd.h> |
| 25 | #include <wait.h> |
| 26 | |
| 27 | |
| 28 | static const char testdata[] = "This is a test"; |
| 29 | static const char testdata2[] = "And here we go again"; |
| 30 | |
| 31 | |
| 32 | int |
| 33 | main (void) |
| 34 | { |
| 35 | const char *tmpdir = getenv ("TMPDIR"); |
| 36 | char buf[100]; |
| 37 | size_t tmpdirlen; |
| 38 | char *name; |
| 39 | int fd; |
| 40 | pid_t pid; |
| 41 | pid_t ppid; |
| 42 | off_t off; |
| 43 | int status; |
| 44 | |
| 45 | if (tmpdir == NULL || *tmpdir == '\0') |
| 46 | tmpdir = "/tmp"; |
| 47 | tmpdirlen = strlen (tmpdir); |
| 48 | |
| 49 | name = (char *) malloc (tmpdirlen + strlen ("/forkXXXXXX") + 1); |
| 50 | if (name == NULL) |
| 51 | error (EXIT_FAILURE, errno, "cannot allocate file name"); |
| 52 | |
| 53 | mempcpy (mempcpy (name, tmpdir, tmpdirlen), |
| 54 | "/forkXXXXXX", sizeof ("/forkXXXXXX")); |
| 55 | |
| 56 | /* Open our test file. */ |
| 57 | fd = mkstemp (name); |
| 58 | if (fd == -1) |
| 59 | error (EXIT_FAILURE, errno, "cannot open test file `%s'", name); |
| 60 | |
| 61 | /* Make sure it gets removed. */ |
| 62 | unlink (name); |
| 63 | |
| 64 | /* Write some data. */ |
| 65 | if (write (fd, testdata, strlen (testdata)) != strlen (testdata)) |
| 66 | error (EXIT_FAILURE, errno, "cannot write test data"); |
| 67 | |
| 68 | /* Get the position in the stream. */ |
| 69 | off = lseek (fd, 0, SEEK_CUR); |
| 70 | if (off == (off_t) -1 || off != strlen (testdata)) |
| 71 | error (EXIT_FAILURE, errno, "wrong file position"); |
| 72 | |
| 73 | /* Get the parent PID. */ |
| 74 | ppid = getpid (); |
| 75 | |
| 76 | /* Now fork of the process. */ |
| 77 | pid = fork (); |
| 78 | if (pid == 0) |
| 79 | { |
| 80 | /* One little test first: the PID must have changed. */ |
| 81 | if (getpid () == ppid) |
| 82 | error (EXIT_FAILURE, 0, "child and parent have same PID"); |
| 83 | |
| 84 | /* Test the `getppid' function. */ |
| 85 | pid = getppid (); |
| 86 | if (pid == (pid_t) -1 ? errno != ENOSYS : pid != ppid) |
| 87 | error (EXIT_FAILURE, 0, |
| 88 | "getppid returned wrong PID (%ld, should be %ld)", |
| 89 | (long int) pid, (long int) ppid); |
| 90 | |
| 91 | /* This is the child. First get the position of the descriptor. */ |
| 92 | off = lseek (fd, 0, SEEK_CUR); |
| 93 | if (off == (off_t) -1 || off != strlen (testdata)) |
| 94 | error (EXIT_FAILURE, errno, "wrong file position in child"); |
| 95 | |
| 96 | /* Reset the position. */ |
| 97 | if (lseek (fd, 0, SEEK_SET) != 0) |
| 98 | error (EXIT_FAILURE, errno, "cannot reset position in child"); |
| 99 | |
| 100 | /* Read the data. */ |
| 101 | if (read (fd, buf, sizeof buf) != strlen (testdata)) |
| 102 | error (EXIT_FAILURE, errno, "cannot read data in child"); |
| 103 | |
| 104 | /* Compare the data. */ |
| 105 | if (memcmp (buf, testdata, strlen (testdata)) != 0) |
| 106 | error (EXIT_FAILURE, 0, "data comparison failed in child"); |
| 107 | |
| 108 | /* Reset position again. */ |
| 109 | if (lseek (fd, 0, SEEK_SET) != 0) |
| 110 | error (EXIT_FAILURE, errno, "cannot reset position again in child"); |
| 111 | |
| 112 | /* Write new data. */ |
| 113 | if (write (fd, testdata2, strlen (testdata2)) != strlen (testdata2)) |
| 114 | error (EXIT_FAILURE, errno, "cannot write new data in child"); |
| 115 | |
| 116 | /* Close the file. This must not remove it. */ |
| 117 | close (fd); |
| 118 | |
| 119 | _exit (0); |
| 120 | } |
| 121 | else if (pid < 0) |
| 122 | /* Something went wrong. */ |
| 123 | error (EXIT_FAILURE, errno, "cannot fork"); |
| 124 | |
| 125 | /* Wait for the child. */ |
| 126 | if (waitpid (pid, &status, 0) != pid) |
| 127 | error (EXIT_FAILURE, 0, "Oops, wrong test program terminated"); |
| 128 | |
| 129 | if (WTERMSIG (status) != 0) |
| 130 | error (EXIT_FAILURE, 0, "Child terminated incorrectly"); |
| 131 | status = WEXITSTATUS (status); |
| 132 | |
| 133 | if (status == 0) |
| 134 | { |
| 135 | /* Test whether the child wrote the right data. First test the |
| 136 | position. It must be the same as in the child. */ |
| 137 | if (lseek (fd, 0, SEEK_CUR) != strlen (testdata2)) |
| 138 | error (EXIT_FAILURE, 0, "file position not changed"); |
| 139 | |
| 140 | if (lseek (fd, 0, SEEK_SET) != 0) |
| 141 | error (EXIT_FAILURE, errno, "cannot reset file position"); |
| 142 | |
| 143 | if (read (fd, buf, sizeof buf) != strlen (testdata2)) |
| 144 | error (EXIT_FAILURE, errno, "cannot read new data"); |
| 145 | |
| 146 | if (memcmp (buf, testdata2, strlen (testdata2)) != 0) |
| 147 | error (EXIT_FAILURE, 0, "new data not read correctly"); |
| 148 | } |
| 149 | |
| 150 | return status; |
| 151 | } |