libprint/common/network.c

	network.c revision 355b4669e025ff377602b6fc7caaf30dbc218371
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*LINTLIBRARY*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <syslog.h>
#include <sys/utsname.h>

#include <network.h>
#include <misc.h>

static int read_wait_time_sec = 60;
static int write_wait_time_sec = 10;

/*
 *	This module implements a set of functions to handle network
 *	communications.  It attempts to hide any "uglyness" that might be
 *	necessary for such communications.
 */


/*
 *  null() is to be used as a signal handler that does nothing.  It is used in
 *	place of SIG_IGN, because we want the signal to be delivered and
 *	interupt the current system call.
 */
static void
null(int i)
{
	syslog(LOG_DEBUG, "null(%d)", i);
}

/*
 *  net_open() opens a tcp connection to the printer port on the host specified
 *	in the arguments passed in.  If the connection is not made in the
 *	timeout (in seconds) passed in, an error it returned.  If the host is
 *	unknown, an error is returned.  If all is well, a file descriptor is
 *	returned to be used for future communications.
 */
int
net_open(char *host, int timeout)
{
	struct hostent *hp;
	struct servent *sp;
	struct sockaddr_in6 sin;
	void (*old_handler)();
	static struct utsname uts;

	int	s,
		lport,
		err,
		error_num;
	unsigned timo = 1;

	syslog(LOG_DEBUG, "net_open(%s, %d)", (host != NULL ? host : "NULL"),
		timeout);
	/*
	 * Get the host address and port number to connect to.
	 */
	if (host == NULL) {
		return (-1);
	}

	(void) memset((char *)&sin, NULL, sizeof (sin));
	if ((hp = getipnodebyname(host, AF_INET6, AI_DEFAULT,
		    &error_num)) == NULL) {
		syslog(LOG_DEBUG|LOG_ERR, "unknown host %s "
		    "getipnodebyname() returned %d", host, error_num);
		return (NETWORK_ERROR_HOST);
	}
	(void) memcpy((caddr_t)&sin.sin6_addr, hp->h_addr, hp->h_length);
	sin.sin6_family = hp->h_addrtype;
	freehostent(hp);

	if ((sp = getservbyname("printer", "tcp")) == NULL) {
		syslog(LOG_DEBUG|LOG_ERR, "printer/tcp: unknown service");
		return (NETWORK_ERROR_SERVICE);
	}
	sin.sin6_port = sp->s_port;

retry:
	/*
	 * Try connecting to the server.
	 *
	 * Use 0 as lport means that rresvport_af() will bind to a port in
	 * the anonymous privileged port range.
	 */
	lport = 0;
	s = rresvport_af(&lport, AF_INET6);
	if (s < 0)
		return (NETWORK_ERROR_PORT);

	old_handler = signal(SIGALRM, null);
	(void) alarm(timeout);
	if (connect(s, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
		(void) alarm(0);
		(void) signal(SIGALRM, old_handler);
		err = errno;
		(void) close(s);
		errno = err;
		if (errno == EADDRINUSE) {
			goto retry;
		}
		/*
		 * If connecting to the local system fails, try
		 * again with "localhost" address instead.
		 */
		if (uts.nodename[0] == '\0')
			(void) uname(&uts);
		if (strcmp(host, uts.nodename) == 0) {
			IN6_IPADDR_TO_V4MAPPED(htonl(INADDR_LOOPBACK),
			    &sin.sin6_addr);
			sin.sin6_family = AF_INET6;
			goto retry;
		}
		if (errno == ECONNREFUSED && timo <= 16) {
			(void) sleep(timo);
			timo *= 2;
			goto retry;
		}
		return (NETWORK_ERROR_UNKNOWN);
	}
	(void) alarm(0);
	(void) signal(SIGALRM, old_handler);
	return (s);
}


/*
 *  net_close() closes a TCP connection opened by net_open()
 */
int
net_close(int nd)
{
	syslog(LOG_DEBUG, "net_close(%d)", nd);
	return (close(nd));
}

/*
 *  net_read() reads up to the length specified into the buffer supplied from
 *	the network connection specified
 */
int
net_read(int nd, char *buf, int len)
{
	int rc;
	void (*old_handler)();

	syslog(LOG_DEBUG, "net_read(%d, 0x%x, %d)", nd, buf, len);
	old_handler = signal(SIGALRM, null);
	(void) alarm(read_wait_time_sec);
	rc = read(nd, buf, len);
	(void) alarm(0);
	(void) signal(SIGALRM, old_handler);
	return (rc);
}


/*
 *  net_write() writes the buffer specified out to the network connection
 *	supplied.
 */
int
net_write(int nd, char *buf, int len)
{
	int rc;
	void (*old_handler)();

	syslog(LOG_DEBUG, "net_write(%d, 0x%x, %d)", nd, buf, len);
	old_handler = signal(SIGALRM, null);
	(void) alarm(write_wait_time_sec);
	rc = write(nd, buf, len);
	(void) alarm(0);
	(void) signal(SIGALRM, old_handler);
	return (rc);
}


/*
 *  net_response() reads in a byte from the network connection and
 *	returns -1 if it isn't 0.
 */
int
net_response(int nd)
{
	char	c;

	syslog(LOG_DEBUG, "net_response(%d)", nd);
	if ((net_read(nd, &c, 1) != 1) || c) {
		errno = EIO;
		return (-1);
	}
	return (0);
}

/*
 *  net_printf() sends a text message out to the network connection supplied
 *	using the same semantics as printf(3C) for stdio.
 */
/*PRINTFLIKE2*/
int
net_printf(int nd, char *fmt, ...)
{
	char *buf;
	va_list	ap;
	int err;
	int size;
	int rc;

	syslog(LOG_DEBUG, "net_printf(%d, %s, ...)", nd, fmt);

	if ((buf = malloc(BUFSIZ)) == NULL) {
		err = errno;
		syslog(LOG_DEBUG, "net_printf malloc failed");
		errno = err;
		return (-1);
	}

	va_start(ap, fmt);
	size = vsnprintf(buf, BUFSIZ, fmt, ap);
	if (size >= BUFSIZ) {
		if ((buf = (char *)realloc(buf, size + 2)) == NULL) {
			err = errno;
			syslog(LOG_DEBUG, "net_printf malloc failed");
			errno = err;
			return (-1);
		}
		size = vsnprintf(buf, size + 1, fmt, ap);
	}
	va_end(ap);


	rc = net_write(nd, buf, (int)strlen(buf));
	free(buf);
	return (rc);
}

/*
 *  net_gets() read from the network connection until either a newline
 *	is encountered, or the buffer passed in is full.  This is similiar
 *	to fgets(3C)
 */
char *
net_gets(char *buf, int bufSize, int nd)
{
	char	tmp;
	int	count = 0;

	syslog(LOG_DEBUG, "net_gets(0x%x, %d, %d)",  buf, bufSize, nd);
	(void) memset(buf, NULL, bufSize);
	while ((count < bufSize) && (net_read(nd, &tmp, 1) > 0))
		if ((buf[count++] = tmp) == '\n') break;

	if (count != 0)
		return (buf);
	return (NULL);
}


/*
 *  net_send_message() sends a message out the network connection using
 *	net_printf() and returns the result from net_response()
 */
/*PRINTFLIKE2*/
int
net_send_message(int nd, char *fmt, ...)
{
	char	buf[BUFSIZ];
	va_list	ap;

	syslog(LOG_DEBUG, "net_send_message(%d, %s, ...)", nd, fmt);
	va_start(ap, fmt);
	if (vsnprintf(buf, sizeof (buf), fmt, ap) >= sizeof (buf)) {
		syslog(LOG_ERR, "libprint:net_send_message: buffer overrun");
		return (-1);
	}
	va_end(ap);

	if (net_write(nd, buf, (int)((strlen(buf) != 0) ? strlen(buf) : 1)) < 0)
		return (-1);
	return (net_response(nd));
}


/*
 *  net_send_file() sends the appropriate rfc1179 file transfer sub message
 *	to notify the remote side it is sending a file.  It then sends the
 *	file if the remote side responds that it is ready.  If the remote side
 *	can't accept the file an error is returned.  If the transfer fails,
 *	an error is returned.
 */
int
net_send_file(int nd, char *name, char *data, int data_size, int type)
{
	char	*truncated_name,
		*mptr,
		*fileBuf = NULL;
	int	count,
		retries = 0,
		size,
		tmperrno;

	syslog(LOG_DEBUG, "net_send_file(%d, %s, 0x%x, %d, %d)", nd,
		(name ? name : "NULL"), data, data_size, type);
	if ((truncated_name = (char *)strrchr(name, '/')) == NULL)
		truncated_name = name;
	else
		truncated_name++;


	if (data == NULL) {
		size = map_in_file(name, &fileBuf, 1);
		mptr = fileBuf;
	} else {
		mptr = data;
		size = data_size;
	}

	if (size < 0) {
		tmperrno = errno; /* because syslog() can change errno */
		syslog(LOG_DEBUG, "net_send_file(%d, %s, 0x%x, %d, %d): %m", nd,
			(name ? name : "NULL"), data, data_size, type);
		errno = tmperrno;
		return (NETWORK_ERROR_UNKNOWN);
	}

						/* send XFER command */
	if (net_send_message(nd, "%c%d %s\n", type, size,
				truncated_name) != 0) {
		(void) munmap(fileBuf, size);
		errno = EIO;
		return (NETWORK_ERROR_SEND_RESPONSE);
	}

						/* send DATA and ACK */
	count = size;
	while (count > 0) {
		int	rc;

		rc = net_write(nd, mptr, count);

		if (rc < 0) {
			if (retries++ < 5) {
				/*
				 * save/restore errno;
				 * will lose if syslogd down
				 */
				tmperrno = errno;
				syslog(LOG_DEBUG,
				    "net_send_file error on write: %m %d",
					retries);
				errno = tmperrno;
				continue;
			}
			/* save/restore errno; will lose if syslogd down */
			tmperrno = errno;
			syslog(LOG_DEBUG, "net_send_file error on write: %m");
			if (fileBuf != NULL)
				(void) munmap(fileBuf, size);
			errno = tmperrno;
			return (-1);

		} else {
			count -= rc;
			mptr += rc;
			retries = 0;
		}
	}

	if (fileBuf != NULL)
		(void) munmap(fileBuf, size);

	if (net_send_message(nd, "", NULL) != 0) {
		errno = EIO;
		return (NETWORK_ERROR_SEND_FAILED);
	}

	return (0);
}