thr_close.c revision 102590
1/* 2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 19 * 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 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD: head/lib/libkse/thread/thr_close.c 102590 2002-08-29 23:06:07Z deischen $ 33 */ 34#include <errno.h> 35#include <stdlib.h> 36#include <unistd.h> 37#include <fcntl.h> 38#include <sys/stat.h> 39#include <pthread.h> 40#include "pthread_private.h" 41 42__weak_reference(__close, close); 43 44int 45_close(int fd) 46{ 47 int flags; 48 int ret; 49 struct stat sb; 50 struct fd_table_entry *entry; 51 52 if ((fd == _thread_kern_pipe[0]) || (fd == _thread_kern_pipe[1])) { 53 /* 54 * Don't allow silly programs to close the kernel pipe. 55 */ 56 errno = EBADF; 57 ret = -1; 58 } 59 /* 60 * Lock the file descriptor while the file is closed and get 61 * the file descriptor status: 62 */ 63 else if (((ret = _FD_LOCK(fd, FD_RDWR, NULL)) == 0) && 64 ((ret = __sys_fstat(fd, &sb)) == 0)) { 65 /* 66 * Check if the file should be left as blocking. 67 * 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. 72 * 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 77 * to access them. 78 * 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 83 * indefinitely. 84 */ 85 if ((S_ISREG(sb.st_mode) || S_ISCHR(sb.st_mode)) 86 && (_thread_fd_getflags(fd) & O_NONBLOCK) == 0) { 87 /* Get the current flags: */ 88 flags = __sys_fcntl(fd, F_GETFL, NULL); 89 /* Clear the nonblocking file descriptor flag: */ 90 __sys_fcntl(fd, F_SETFL, flags & ~O_NONBLOCK); 91 } 92 93 /* XXX: Assumes well behaved threads. */ 94 /* XXX: Defer real close to avoid race condition */ 95 entry = _thread_fd_table[fd]; 96 _thread_fd_table[fd] = NULL; 97 free(entry); 98 99 /* Close the file descriptor: */ 100 ret = __sys_close(fd); 101 } 102 return (ret); 103} 104 105int 106__close(int fd) 107{ 108 int ret; 109 110 _thread_enter_cancellation_point(); 111 ret = _close(fd); 112 _thread_leave_cancellation_point(); 113 114 return ret; 115} 116