1 /* $OpenBSD: uthread_read.c,v 1.7 2001/08/21 19:24:53 fgsch Exp $ */
2 /*
3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by John Birrell.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: uthread_read.c,v 1.8 1999/08/28 00:03:43 peter Exp $
34 *
35 */
36 #include <sys/types.h>
37 #include <sys/fcntl.h>
38 #include <sys/uio.h>
39 #include <errno.h>
40 #include <unistd.h>
41 #ifdef _THREAD_SAFE
42 #include <pthread.h>
43 #include "pthread_private.h"
44
45 ssize_t
read(int fd,void * buf,size_t nbytes)46 read(int fd, void *buf, size_t nbytes)
47 {
48 struct pthread *curthread = _get_curthread();
49 ssize_t ret;
50 int type;
51
52 /* This is a cancellation point: */
53 _thread_enter_cancellation_point();
54
55 /* POSIX says to do just this: */
56 if (nbytes == 0)
57 ret = 0;
58
59 /* Lock the file descriptor for read: */
60 else if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
61 /* Get the read/write mode type: */
62 type = _thread_fd_table[fd]->flags & O_ACCMODE;
63
64 /* Check if the file is not open for read: */
65 if (type != O_RDONLY && type != O_RDWR) {
66 /* File is not open for read: */
67 errno = EBADF;
68 ret = -1;
69 }
70
71 /* Perform a non-blocking read syscall: */
72 else while ((ret = _thread_sys_read(fd, buf, nbytes)) < 0) {
73 if ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0 &&
74 (errno == EWOULDBLOCK || errno == EAGAIN)) {
75 curthread->data.fd.fd = fd;
76 _thread_kern_set_timeout(NULL);
77
78 /* Reset the interrupted operation flag: */
79 curthread->interrupted = 0;
80
81 _thread_kern_sched_state(PS_FDR_WAIT,
82 __FILE__, __LINE__);
83
84 /*
85 * Check if the operation was
86 * interrupted by a signal
87 */
88 if (curthread->interrupted) {
89 errno = EINTR;
90 ret = -1;
91 break;
92 }
93 } else {
94 break;
95 }
96 }
97 _FD_UNLOCK(fd, FD_READ);
98 }
99
100 /* No longer in a cancellation point: */
101 _thread_leave_cancellation_point();
102
103 return (ret);
104 }
105 #endif
106