1 /* $OpenBSD: uthread_close.c,v 1.11 2003/12/23 20:03:54 marc Exp $ */
2 /*
3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by John Birrell.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: uthread_close.c,v 1.7 1999/08/28 00:03:26 peter Exp $
34 */
35 #include <errno.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 #include <fcntl.h>
39 #include <sys/stat.h>
40 #ifdef _THREAD_SAFE
41 #include <pthread.h>
42 #include "pthread_private.h"
43
44 int
close(int fd)45 close(int fd)
46 {
47 int flags;
48 int ret;
49 struct stat sb;
50
51 /* This is a cancelation point: */
52 _thread_enter_cancellation_point();
53
54 if ((fd < 0) || (fd >= _thread_dtablesize) ||
55 (fd == _thread_kern_pipe[0]) || (fd == _thread_kern_pipe[1])) {
56 errno = EBADF;
57 ret = -1;
58 } else if (_thread_fd_table[fd] == NULL)
59 /* unknown to thread kernel, let system handle the close */
60 ret = _thread_sys_close(fd);
61 else if ((ret = _FD_LOCK(fd, FD_RDWR, NULL)) == 0) {
62 /*
63 * Check if the file should be left as blocking.
64 *
65 * This is so that the file descriptors shared with a parent
66 * process aren't left set to non-blocking if the child
67 * closes them prior to exit. An example where this causes
68 * problems with /bin/sh is when a child closes stdin.
69 *
70 * Setting a file as blocking causes problems if a threaded
71 * parent accesses the file descriptor before the child exits.
72 * Once the threaded parent receives a SIGCHLD then it resets
73 * all of its files to non-blocking, and so it is then safe
74 * to access them.
75 *
76 * Pipes are not set to blocking when they are closed, as
77 * the parent and child will normally close the file
78 * descriptor of the end of the pipe that they are not
79 * using, which would then cause any reads to block
80 * indefinitely.
81 *
82 * Files that we cannot fstat are probably not regular
83 * so we don't bother with them.
84 */
85
86 if ((_thread_sys_fstat(fd, &sb) == 0) &&
87 ((S_ISREG(sb.st_mode) || S_ISCHR(sb.st_mode)) &&
88 (_thread_fd_table[fd]->flags & O_NONBLOCK) == 0))
89 {
90 /* Get the current flags: */
91 flags = _thread_sys_fcntl(fd, F_GETFL, NULL);
92 /* Clear the nonblocking file descriptor flag: */
93 _thread_sys_fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
94 }
95
96 /* XXX: Assumes well behaved threads. */
97 /* XXX: Defer real close to avoid race condition */
98 _thread_fd_table_remove(fd);
99 /* Close the file descriptor: */
100 ret = _thread_sys_close(fd);
101 }
102
103 /* No longer in a cancellation point: */
104 _thread_leave_cancellation_point();
105
106 return (ret);
107 }
108 #endif
109