freebsd-dev/usr.sbin/lpr/common_source/net.c
1999-08-28 01:35:59 +00:00

266 lines
7.3 KiB
C

/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* From: @(#)common.c 8.5 (Berkeley) 4/28/95
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <dirent.h> /* required for lp.h, not used here */
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"
/* host machine name */
char host[MAXHOSTNAMELEN];
char *from = host; /* client's machine name */
extern uid_t uid, euid;
/*
* Create a TCP connection to host "rhost" at port "rport".
* If rport == 0, then use the printer service port.
* Most of this code comes from rcmd.c.
*/
int
getport(const struct printer *pp, const char *rhost, int rport)
{
struct hostent *hp;
struct servent *sp;
struct sockaddr_in sin;
int s, timo = 1, lport = IPPORT_RESERVED - 1;
int err;
/*
* Get the host address and port number to connect to.
*/
if (rhost == NULL)
fatal(pp, "no remote host to connect to");
bzero((char *)&sin, sizeof(sin));
sin.sin_len = sizeof sin;
sin.sin_family = AF_INET;
if (inet_aton(rhost, &sin.sin_addr) == 0) {
hp = gethostbyname2(rhost, AF_INET);
if (hp == NULL)
fatal(pp, "cannot resolve %s: %s", rhost,
hstrerror(h_errno));
/* XXX - should deal with more addresses */
sin.sin_addr = *(struct in_addr *)hp->h_addr_list[0];
}
if (rport == 0) {
sp = getservbyname("printer", "tcp");
if (sp == NULL)
fatal(pp, "printer/tcp: unknown service");
sin.sin_port = sp->s_port;
} else
sin.sin_port = htons(rport);
/*
* Try connecting to the server.
*/
retry:
seteuid(euid);
s = rresvport(&lport);
seteuid(uid);
if (s < 0)
return(-1);
if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
err = errno;
(void) close(s);
errno = err;
/*
* This used to decrement lport, but the current semantics
* of rresvport do not provide such a function (in fact,
* rresvport should guarantee that the chosen port will
* never result in an EADDRINUSE).
*/
if (errno == EADDRINUSE)
goto retry;
if (errno == ECONNREFUSED && timo <= 16) {
sleep(timo);
timo *= 2;
goto retry;
}
return(-1);
}
return(s);
}
/*
* Figure out whether the local machine is the same
* as the remote machine (RM) entry (if it exists).
* We do this by counting the intersection of our
* address list and theirs. This is better than the
* old method (comparing the canonical names), as it
* allows load-sharing between multiple print servers.
* The return value is an error message which must be
* free()d.
*/
char *
checkremote(struct printer *pp)
{
char name[MAXHOSTNAMELEN];
register struct hostent *hp;
char *err;
struct in_addr *localaddrs;
int i, j, nlocaladdrs, ncommonaddrs;
if (!pp->rp_matches_local) { /* Remote printer doesn't match local */
pp->remote = 1;
return NULL;
}
pp->remote = 0; /* assume printer is local */
if (pp->remote_host != NULL) {
/* get the addresses of the local host */
gethostname(name, sizeof(name));
name[sizeof(name) - 1] = '\0';
hp = gethostbyname2(name, AF_INET);
if (hp == (struct hostent *) NULL) {
asprintf(&err, "unable to get official name "
"for local machine %s: %s",
name, hstrerror(h_errno));
return err;
}
for (i = 0; hp->h_addr_list[i]; i++)
;
nlocaladdrs = i;
localaddrs = malloc(i * sizeof(struct in_addr));
if (localaddrs == 0) {
asprintf(&err, "malloc %lu bytes failed",
(u_long)i * sizeof(struct in_addr));
return err;
}
for (i = 0; hp->h_addr_list[i]; i++)
localaddrs[i] = *(struct in_addr *)hp->h_addr_list[i];
/* get the official name of RM */
hp = gethostbyname2(pp->remote_host, AF_INET);
if (hp == (struct hostent *) NULL) {
asprintf(&err, "unable to get address list for "
"remote machine %s: %s",
pp->remote_host, hstrerror(h_errno));
free(localaddrs);
return err;
}
ncommonaddrs = 0;
for (i = 0; i < nlocaladdrs; i++) {
for (j = 0; hp->h_addr_list[j]; j++) {
char *them = hp->h_addr_list[j];
if (localaddrs[i].s_addr ==
(*(struct in_addr *)them).s_addr)
ncommonaddrs++;
}
}
/*
* if the two hosts do not share at least one IP address
* then the printer must be remote.
*/
if (ncommonaddrs == 0)
pp->remote = 1;
free(localaddrs);
}
return NULL;
}
/*
* This isn't really network-related, but it's used here to write
* multi-part strings onto sockets without using stdio. Return
* values are as for writev(2).
*/
ssize_t
writel(int s, ...)
{
va_list ap;
int i, n;
const char *cp;
#define NIOV 12
struct iovec iov[NIOV], *iovp = iov;
ssize_t retval;
/* first count them */
va_start(ap, s);
n = 0;
do {
cp = va_arg(ap, char *);
n++;
} while (cp);
va_end(ap);
n--; /* correct for count of trailing null */
if (n > NIOV) {
iovp = malloc(n * sizeof *iovp);
if (iovp == 0)
return -1;
}
/* now make up iovec and send */
va_start(ap, s);
for (i = 0; i < n; i++) {
iovp[i].iov_base = va_arg(ap, char *);
iovp[i].iov_len = strlen(iovp[i].iov_base);
}
va_end(ap);
retval = writev(s, iovp, n);
if (iovp != iov)
free(iovp);
return retval;
}