104 lines
3.8 KiB
C
104 lines
3.8 KiB
C
/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: uthread_close.c,v 1.5 1999/06/20 08:28:11 jb Exp $
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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int
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close(int fd)
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{
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int flags;
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int ret;
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int status;
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struct stat sb;
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struct fd_table_entry *entry;
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if ((fd == _thread_kern_pipe[0]) || (fd == _thread_kern_pipe[1])) {
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/*
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* Don't allow silly programs to close the kernel pipe.
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*/
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errno = EBADF;
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ret = -1;
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}
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/*
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* Lock the file descriptor while the file is closed and get
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* the file descriptor status:
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*/
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else if (((ret = _FD_LOCK(fd, FD_RDWR, NULL)) == 0) &&
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((ret = _thread_sys_fstat(fd, &sb)) == 0)) {
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/*
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* Check if the file should be left as blocking.
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*
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* This is so that the file descriptors shared with a parent
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* process aren't left set to non-blocking if the child
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* closes them prior to exit. An example where this causes
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* problems with /bin/sh is when a child closes stdin.
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*
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* Setting a file as blocking causes problems if a threaded
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* parent accesses the file descriptor before the child exits.
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* Once the threaded parent receives a SIGCHLD then it resets
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* all of its files to non-blocking, and so it is then safe
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* to access them.
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*
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* Pipes are not set to blocking when they are closed, as
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* the parent and child will normally close the file
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* descriptor of the end of the pipe that they are not
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* using, which would then cause any reads to block
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* indefinitely.
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*/
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if ((S_ISREG(sb.st_mode) || S_ISCHR(sb.st_mode)) && (_thread_fd_table[fd]->flags & O_NONBLOCK) == 0) {
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/* Get the current flags: */
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flags = _thread_sys_fcntl(fd, F_GETFL, NULL);
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/* Clear the nonblocking file descriptor flag: */
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_thread_sys_fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
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}
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/* XXX: Assumes well behaved threads. */
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/* XXX: Defer real close to avoid race condition */
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entry = _thread_fd_table[fd];
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_thread_fd_table[fd] = NULL;
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free(entry);
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/* Close the file descriptor: */
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ret = _thread_sys_close(fd);
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}
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return (ret);
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}
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#endif
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