2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * $Id: uthread_close.c,v 1.5 1999/06/20 08:28:11 jb Exp $
41 #include "pthread_private.h"
50 struct fd_table_entry *entry;
52 if ((fd == _thread_kern_pipe[0]) || (fd == _thread_kern_pipe[1])) {
54 * Don't allow silly programs to close the kernel pipe.
60 * Lock the file descriptor while the file is closed and get
61 * the file descriptor status:
63 else if (((ret = _FD_LOCK(fd, FD_RDWR, NULL)) == 0) &&
64 ((ret = _thread_sys_fstat(fd, &sb)) == 0)) {
66 * Check if the file should be left as blocking.
68 * This is so that the file descriptors shared with a parent
69 * process aren't left set to non-blocking if the child
70 * closes them prior to exit. An example where this causes
71 * problems with /bin/sh is when a child closes stdin.
73 * Setting a file as blocking causes problems if a threaded
74 * parent accesses the file descriptor before the child exits.
75 * Once the threaded parent receives a SIGCHLD then it resets
76 * all of its files to non-blocking, and so it is then safe
79 * Pipes are not set to blocking when they are closed, as
80 * the parent and child will normally close the file
81 * descriptor of the end of the pipe that they are not
82 * using, which would then cause any reads to block
85 if ((S_ISREG(sb.st_mode) || S_ISCHR(sb.st_mode)) && (_thread_fd_table[fd]->flags & O_NONBLOCK) == 0) {
86 /* Get the current flags: */
87 flags = _thread_sys_fcntl(fd, F_GETFL, NULL);
88 /* Clear the nonblocking file descriptor flag: */
89 _thread_sys_fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
92 /* XXX: Assumes well behaved threads. */
93 /* XXX: Defer real close to avoid race condition */
94 entry = _thread_fd_table[fd];
95 _thread_fd_table[fd] = NULL;
98 /* Close the file descriptor: */
99 ret = _thread_sys_close(fd);