thr_read.c revision 71581 
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_read.c 71581 2001-01-24 13:03:38Z deischen $
33 *
34 */
35#include <sys/types.h>
36#include <sys/fcntl.h>
37#include <sys/uio.h>
38#include <errno.h>
39#include <unistd.h>
40#include <pthread.h>
41#include "pthread_private.h"
42
43#pragma weak	read=__read
44
45ssize_t
46_read(int fd, void *buf, size_t nbytes)
47{
48	struct pthread	*curthread = _get_curthread();
49	int	ret;
50	int	type;
51
52	/* POSIX says to do just this: */
53	if (nbytes == 0) {
54		return (0);
55	}
56
57	/* Lock the file descriptor for read: */
58	if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
59		/* Get the read/write mode type: */
60		type = _thread_fd_table[fd]->flags & O_ACCMODE;
61
62		/* Check if the file is not open for read: */
63		if (type != O_RDONLY && type != O_RDWR) {
64			/* File is not open for read: */
65			errno = EBADF;
66			_FD_UNLOCK(fd, FD_READ);
67			return (-1);
68		}
69
70		/* Perform a non-blocking read syscall: */
71		while ((ret = __sys_read(fd, buf, nbytes)) < 0) {
72			if ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0 &&
73			    (errno == EWOULDBLOCK || errno == EAGAIN)) {
74				curthread->data.fd.fd = fd;
75				_thread_kern_set_timeout(NULL);
76
77				/* Reset the interrupted operation flag: */
78				curthread->interrupted = 0;
79
80				_thread_kern_sched_state(PS_FDR_WAIT,
81				    __FILE__, __LINE__);
82
83				/*
84				 * Check if the operation was
85				 * interrupted by a signal
86				 */
87				if (curthread->interrupted) {
88					errno = EINTR;
89					ret = -1;
90					break;
91				}
92			} else {
93				break;
94			}
95		}
96		_FD_UNLOCK(fd, FD_READ);
97	}
98	return (ret);
99}
100
101ssize_t
102__read(int fd, void *buf, size_t nbytes)
103{
104	ssize_t	ret;
105
106	_thread_enter_cancellation_point();
107	ret = _read(fd, buf, nbytes);
108	_thread_leave_cancellation_point();
109
110	return ret;
111}
112