2 Copyright (C) 2000-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
27 static const char testdata
[] = "This is a test";
28 static const char testdata2
[] = "And here we go again";
34 const char *tmpdir
= getenv ("TMPDIR");
44 if (tmpdir
== NULL
|| *tmpdir
== '\0')
46 tmpdirlen
= strlen (tmpdir
);
48 name
= (char *) malloc (tmpdirlen
+ strlen ("/forkXXXXXX") + 1);
50 error (EXIT_FAILURE
, errno
, "cannot allocate file name");
52 mempcpy (mempcpy (name
, tmpdir
, tmpdirlen
),
53 "/forkXXXXXX", sizeof ("/forkXXXXXX"));
55 /* Open our test file. */
58 error (EXIT_FAILURE
, errno
, "cannot open test file `%s'", name
);
60 /* Make sure it gets removed. */
63 /* Write some data. */
64 if (write (fd
, testdata
, strlen (testdata
)) != strlen (testdata
))
65 error (EXIT_FAILURE
, errno
, "cannot write test data");
67 /* Get the position in the stream. */
68 off
= lseek (fd
, 0, SEEK_CUR
);
69 if (off
== (off_t
) -1 || off
!= strlen (testdata
))
70 error (EXIT_FAILURE
, errno
, "wrong file position");
72 /* Get the parent PID. */
75 /* Now fork of the process. */
79 /* One little test first: the PID must have changed. */
80 if (getpid () == ppid
)
81 error (EXIT_FAILURE
, 0, "child and parent have same PID");
83 /* Test the `getppid' function. */
85 if (pid
== (pid_t
) -1 ? errno
!= ENOSYS
: pid
!= ppid
)
86 error (EXIT_FAILURE
, 0,
87 "getppid returned wrong PID (%ld, should be %ld)",
88 (long int) pid
, (long int) ppid
);
90 /* This is the child. First get the position of the descriptor. */
91 off
= lseek (fd
, 0, SEEK_CUR
);
92 if (off
== (off_t
) -1 || off
!= strlen (testdata
))
93 error (EXIT_FAILURE
, errno
, "wrong file position in child");
95 /* Reset the position. */
96 if (lseek (fd
, 0, SEEK_SET
) != 0)
97 error (EXIT_FAILURE
, errno
, "cannot reset position in child");
100 if (read (fd
, buf
, sizeof buf
) != strlen (testdata
))
101 error (EXIT_FAILURE
, errno
, "cannot read data in child");
103 /* Compare the data. */
104 if (memcmp (buf
, testdata
, strlen (testdata
)) != 0)
105 error (EXIT_FAILURE
, 0, "data comparison failed in child");
107 /* Reset position again. */
108 if (lseek (fd
, 0, SEEK_SET
) != 0)
109 error (EXIT_FAILURE
, errno
, "cannot reset position again in child");
111 /* Write new data. */
112 if (write (fd
, testdata2
, strlen (testdata2
)) != strlen (testdata2
))
113 error (EXIT_FAILURE
, errno
, "cannot write new data in child");
115 /* Close the file. This must not remove it. */
121 /* Something went wrong. */
122 error (EXIT_FAILURE
, errno
, "cannot fork");
124 /* Wait for the child. */
125 if (waitpid (pid
, &status
, 0) != pid
)
126 error (EXIT_FAILURE
, 0, "Oops, wrong test program terminated");
128 if (WTERMSIG (status
) != 0)
129 error (EXIT_FAILURE
, 0, "Child terminated incorrectly");
130 status
= WEXITSTATUS (status
);
134 /* Test whether the child wrote the right data. First test the
135 position. It must be the same as in the child. */
136 if (lseek (fd
, 0, SEEK_CUR
) != strlen (testdata2
))
137 error (EXIT_FAILURE
, 0, "file position not changed");
139 if (lseek (fd
, 0, SEEK_SET
) != 0)
140 error (EXIT_FAILURE
, errno
, "cannot reset file position");
142 if (read (fd
, buf
, sizeof buf
) != strlen (testdata2
))
143 error (EXIT_FAILURE
, errno
, "cannot read new data");
145 if (memcmp (buf
, testdata2
, strlen (testdata2
)) != 0)
146 error (EXIT_FAILURE
, 0, "new data not read correctly");