thr_read.c revision 53812 
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 53812 1999-11-28 05:38:13Z alfred $
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#ifdef _THREAD_SAFE
41#include <pthread.h>
42#include "pthread_private.h"
43
44ssize_t
45read(int fd, void *buf, size_t nbytes)
46{
47	int	ret;
48	int	type;
49
50	_thread_enter_cancellation_point();
51
52	/* POSIX says to do just this: */
53	if (nbytes == 0) {
54		_thread_leave_cancellation_point();
55		return (0);
56	}
57
58	/* Lock the file descriptor for read: */
59	if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
60		/* Get the read/write mode type: */
61		type = _thread_fd_table[fd]->flags & O_ACCMODE;
62
63		/* Check if the file is not open for read: */
64		if (type != O_RDONLY && type != O_RDWR) {
65			/* File is not open for read: */
66			errno = EBADF;
67			_FD_UNLOCK(fd, FD_READ);
68			_thread_leave_cancellation_point();
69			return (-1);
70		}
71
72		/* Perform a non-blocking read syscall: */
73		while ((ret = _thread_sys_read(fd, buf, nbytes)) < 0) {
74			if ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0 &&
75			    (errno == EWOULDBLOCK || errno == EAGAIN)) {
76				_thread_run->data.fd.fd = fd;
77				_thread_kern_set_timeout(NULL);
78
79				/* Reset the interrupted operation flag: */
80				_thread_run->interrupted = 0;
81
82				_thread_kern_sched_state(PS_FDR_WAIT,
83				    __FILE__, __LINE__);
84
85				/*
86				 * Check if the operation was
87				 * interrupted by a signal
88				 */
89				if (_thread_run->interrupted) {
90					errno = EINTR;
91					ret = -1;
92					break;
93				}
94			} else {
95				break;
96			}
97		}
98		_FD_UNLOCK(fd, FD_READ);
99	}
100	_thread_leave_cancellation_point();
101	return (ret);
102}
103#endif
104