lib/libc_r/uthread/uthread_read.c

   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: src/lib/libc_r/uthread/uthread_read.c,v 1.11.2.4 2002/10/22 14:44:03 fjoe Exp $
  33  * $DragonFly: src/lib/libc_r/uthread/uthread_read.c,v 1.4 2007/01/08 21:41:53 dillon 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 #include <pthread.h>
  42 #include "pthread_private.h"
  43
  44 ssize_t
  45 _read(int fd, void *buf, size_t nbytes)
  46 {
  47         struct pthread  *curthread = _get_curthread();
  48         int     ret;
  49         int     type;
  50
  51         /* POSIX says to do just this: */
  52         if (nbytes == 0) {
  53                 return (0);
  54         }
  55
  56         /* Lock the file descriptor for read: */
  57         if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
  58                 /* Get the read/write mode type: */
  59                 type = _thread_fd_getflags(fd) & O_ACCMODE;
  60
  61                 /* Check if the file is not open for read: */
  62                 if (type != O_RDONLY && type != O_RDWR) {
  63                         /* File is not open for read: */
  64                         errno = EBADF;
  65                         _FD_UNLOCK(fd, FD_READ);
  66                         return (-1);
  67                 }
  68
  69                 /* Perform a non-blocking read syscall: */
  70                 while ((ret = __sys_extpread(fd, buf, nbytes, O_FNONBLOCKING, -1)) < 0) {
  71                         if ((_thread_fd_getflags(fd) & O_NONBLOCK) == 0 &&
  72                             (errno == EWOULDBLOCK || errno == EAGAIN)) {
  73                                 curthread->data.fd.fd = fd;
  74                                 _thread_kern_set_timeout(NULL);
  75
  76                                 /* Reset the interrupted operation flag: */
  77                                 curthread->interrupted = 0;
  78
  79                                 _thread_kern_sched_state(PS_FDR_WAIT,
  80                                     __FILE__, __LINE__);
  81
  82                                 /*
  83                                  * Check if the operation was
  84                                  * interrupted by a signal
  85                                  */
  86                                 if (curthread->interrupted) {
  87                                         errno = EINTR;
  88                                         ret = -1;
  89                                         break;
  90                                 }
  91                         } else {
  92                                 break;
  93                         }
  94                 }
  95                 _FD_UNLOCK(fd, FD_READ);
  96         }
  97         return (ret);
  98 }
  99
 100 ssize_t
 101 read(int fd, void *buf, size_t nbytes)
 102 {
 103         ssize_t ret;
 104
 105         _thread_enter_cancellation_point();
 106         ret = _read(fd, buf, nbytes);
 107         _thread_leave_cancellation_point();
 108
 109         return ret;
 110 }