path: root/camel/camel-io.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Authors: Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2003 Ximian, Inc. (www.ximian.com)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#include "camel-io.h"
#include "camel-operation.h"


#ifndef MAX
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#endif

/* FIXME: should we trade out select() for a poll() instead? */

ssize_t
camel_read (int fd, char *buf, size_t n)
{
    ssize_t nread;
    int cancel_fd;
    
    if (camel_operation_cancel_check (NULL)) {
        errno = EINTR;
        return -1;
    }
    
    cancel_fd = camel_operation_cancel_fd (NULL);
    if (cancel_fd == -1) {
        do {
            nread = read (fd, buf, n);
        } while (nread == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
    } else {
        int errnosav, flags, fdmax;
        fd_set rdset;
        
        flags = fcntl (fd, F_GETFL);
        fcntl (fd, F_SETFL, flags | O_NONBLOCK);
        
        do {
            FD_ZERO (&rdset);
            FD_SET (fd, &rdset);
            FD_SET (cancel_fd, &rdset);
            fdmax = MAX (fd, cancel_fd) + 1;
            
            nread = -1;
            if (select (fdmax, &rdset, 0, 0, NULL) != -1) {
                if (FD_ISSET (cancel_fd, &rdset)) {
                    fcntl (fd, F_SETFL, flags);
                    errno = EINTR;
                    return -1;
                }
                
                do {
                    nread = read (fd, buf, n);
                } while (nread == -1 && errno == EINTR);
            } else if (errno == EINTR) {
                errno = EAGAIN;
            }
        } while (nread == -1 && (errno == EAGAIN || errno == EWOULDBLOCK));
        
        errnosav = errno;
        fcntl (fd, F_SETFL, flags);
        errno = errnosav;
    }
    
    return nread;
}


ssize_t
camel_write (int fd, const char *buf, size_t n)
{
    ssize_t w, written = 0;
    int cancel_fd;
    
    if (camel_operation_cancel_check (NULL)) {
        errno = EINTR;
        return -1;
    }
    
    cancel_fd = camel_operation_cancel_fd (NULL);
    if (cancel_fd == -1) {
        do {
            do {
                w = write (fd, buf + written, n - written);
            } while (w == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
            
            if (w > 0)
                written += w;
        } while (w != -1 && written < n);
    } else {
        int errnosav, flags, fdmax;
        fd_set rdset, wrset;
        
        flags = fcntl (fd, F_GETFL);
        fcntl (fd, F_SETFL, flags | O_NONBLOCK);
        
        fdmax = MAX (fd, cancel_fd) + 1;
        do {
            FD_ZERO (&rdset);
            FD_ZERO (&wrset);
            FD_SET (fd, &wrset);
            FD_SET (cancel_fd, &rdset);
            
            w = -1;
            if (select (fdmax, &rdset, &wrset, 0, NULL) != -1) {
                if (FD_ISSET (cancel_fd, &rdset)) {
                    fcntl (fd, F_SETFL, flags);
                    errno = EINTR;
                    return -1;
                }
                
                do {
                    w = write (fd, buf + written, n - written);
                } while (w == -1 && errno == EINTR);
                
                if (w == -1) {
                    if (errno == EAGAIN || errno == EWOULDBLOCK) {
                        w = 0;
                    } else {
                        errnosav = errno;
                        fcntl (fd, F_SETFL, flags);
                        errno = errnosav;
                        return -1;
                    }
                } else
                    written += w;
            } else if (errno == EINTR) {
                w = 0;
            }
        } while (w != -1 && written < n);
        
        errnosav = errno;
        fcntl (fd, F_SETFL, flags);
        errno = errnosav;
    }
    
    if (w == -1)
        return -1;
    
    return written;
}