4.4BSD/usr/src/usr.sbin/lpr/lpd/lpd.c
/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
*
* 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.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1983, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)lpd.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
/*
* lpd -- line printer daemon.
*
* Listen for a connection and perform the requested operation.
* Operations are:
* \1printer\n
* check the queue for jobs and print any found.
* \2printer\n
* receive a job from another machine and queue it.
* \3printer [users ...] [jobs ...]\n
* return the current state of the queue (short form).
* \4printer [users ...] [jobs ...]\n
* return the current state of the queue (long form).
* \5printer person [users ...] [jobs ...]\n
* remove jobs from the queue.
*
* Strategy to maintain protected spooling area:
* 1. Spooling area is writable only by daemon and spooling group
* 2. lpr runs setuid root and setgrp spooling group; it uses
* root to access any file it wants (verifying things before
* with an access call) and group id to know how it should
* set up ownership of files in the spooling area.
* 3. Files in spooling area are owned by root, group spooling
* group, with mode 660.
* 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to
* access files and printer. Users can't get to anything
* w/o help of lpq and lprm programs.
*/
#include <sys/param.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <netdb.h>
#include <unistd.h>
#include <syslog.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"
#include "extern.h"
int lflag; /* log requests flag */
int from_remote; /* from remote socket */
static void reapchild __P((int));
static void mcleanup __P((int));
static void doit __P((void));
static void startup __P((void));
static void chkhost __P((struct sockaddr_in *));
int
main(argc, argv)
int argc;
char **argv;
{
int f, funix, finet, options, fromlen;
fd_set defreadfds;
struct sockaddr_un un, fromunix;
struct sockaddr_in sin, frominet;
int omask, lfd;
options = 0;
gethostname(host, sizeof(host));
name = argv[0];
while (--argc > 0) {
argv++;
if (argv[0][0] == '-')
switch (argv[0][1]) {
case 'd':
options |= SO_DEBUG;
break;
case 'l':
lflag++;
break;
}
}
#ifndef DEBUG
/*
* Set up standard environment by detaching from the parent.
*/
daemon(0, 0);
#endif
openlog("lpd", LOG_PID, LOG_LPR);
syslog(LOG_INFO, "restarted");
(void) umask(0);
lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT, 0644);
if (lfd < 0) {
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
if (flock(lfd, LOCK_EX|LOCK_NB) < 0) {
if (errno == EWOULDBLOCK) /* active deamon present */
exit(0);
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
ftruncate(lfd, 0);
/*
* write process id for others to know
*/
sprintf(line, "%u\n", getpid());
f = strlen(line);
if (write(lfd, line, f) != f) {
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
signal(SIGCHLD, reapchild);
/*
* Restart all the printers.
*/
startup();
(void) unlink(_PATH_SOCKETNAME);
funix = socket(AF_UNIX, SOCK_STREAM, 0);
if (funix < 0) {
syslog(LOG_ERR, "socket: %m");
exit(1);
}
#define mask(s) (1 << ((s) - 1))
omask = sigblock(mask(SIGHUP)|mask(SIGINT)|mask(SIGQUIT)|mask(SIGTERM));
signal(SIGHUP, mcleanup);
signal(SIGINT, mcleanup);
signal(SIGQUIT, mcleanup);
signal(SIGTERM, mcleanup);
un.sun_family = AF_UNIX;
strcpy(un.sun_path, _PATH_SOCKETNAME);
#ifndef SUN_LEN
#define SUN_LEN(unp) (strlen((unp)->sun_path) + 2)
#endif
if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) {
syslog(LOG_ERR, "ubind: %m");
exit(1);
}
sigsetmask(omask);
FD_ZERO(&defreadfds);
FD_SET(funix, &defreadfds);
listen(funix, 5);
finet = socket(AF_INET, SOCK_STREAM, 0);
if (finet >= 0) {
struct servent *sp;
if (options & SO_DEBUG)
if (setsockopt(finet, SOL_SOCKET, SO_DEBUG, 0, 0) < 0) {
syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
mcleanup(0);
}
sp = getservbyname("printer", "tcp");
if (sp == NULL) {
syslog(LOG_ERR, "printer/tcp: unknown service");
mcleanup(0);
}
sin.sin_family = AF_INET;
sin.sin_port = sp->s_port;
if (bind(finet, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
syslog(LOG_ERR, "bind: %m");
mcleanup(0);
}
FD_SET(finet, &defreadfds);
listen(finet, 5);
}
/*
* Main loop: accept, do a request, continue.
*/
for (;;) {
int domain, nfds, s;
fd_set readfds;
FD_COPY(&defreadfds, &readfds);
nfds = select(20, &readfds, 0, 0, 0);
if (nfds <= 0) {
if (nfds < 0 && errno != EINTR)
syslog(LOG_WARNING, "select: %m");
continue;
}
if (FD_ISSET(funix, &readfds)) {
domain = AF_UNIX, fromlen = sizeof(fromunix);
s = accept(funix,
(struct sockaddr *)&fromunix, &fromlen);
} else /* if (FD_ISSET(finet, &readfds)) */ {
domain = AF_INET, fromlen = sizeof(frominet);
s = accept(finet,
(struct sockaddr *)&frominet, &fromlen);
}
if (s < 0) {
if (errno != EINTR)
syslog(LOG_WARNING, "accept: %m");
continue;
}
if (fork() == 0) {
signal(SIGCHLD, SIG_IGN);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
(void) close(funix);
(void) close(finet);
dup2(s, 1);
(void) close(s);
if (domain == AF_INET) {
from_remote = 1;
chkhost(&frominet);
} else
from_remote = 0;
doit();
exit(0);
}
(void) close(s);
}
}
static void
reapchild(signo)
int signo;
{
union wait status;
while (wait3((int *)&status, WNOHANG, 0) > 0)
;
}
static void
mcleanup(signo)
int signo;
{
if (lflag)
syslog(LOG_INFO, "exiting");
unlink(_PATH_SOCKETNAME);
exit(0);
}
/*
* Stuff for handling job specifications
*/
char *user[MAXUSERS]; /* users to process */
int users; /* # of users in user array */
int requ[MAXREQUESTS]; /* job number of spool entries */
int requests; /* # of spool requests */
char *person; /* name of person doing lprm */
char fromb[MAXHOSTNAMELEN]; /* buffer for client's machine name */
char cbuf[BUFSIZ]; /* command line buffer */
char *cmdnames[] = {
"null",
"printjob",
"recvjob",
"displayq short",
"displayq long",
"rmjob"
};
static void
doit()
{
register char *cp;
register int n;
for (;;) {
cp = cbuf;
do {
if (cp >= &cbuf[sizeof(cbuf) - 1])
fatal("Command line too long");
if ((n = read(1, cp, 1)) != 1) {
if (n < 0)
fatal("Lost connection");
return;
}
} while (*cp++ != '\n');
*--cp = '\0';
cp = cbuf;
if (lflag) {
if (*cp >= '\1' && *cp <= '\5')
syslog(LOG_INFO, "%s requests %s %s",
from, cmdnames[*cp], cp+1);
else
syslog(LOG_INFO, "bad request (%d) from %s",
*cp, from);
}
switch (*cp++) {
case '\1': /* check the queue and print any jobs there */
printer = cp;
printjob();
break;
case '\2': /* receive files to be queued */
if (!from_remote) {
syslog(LOG_INFO, "illegal request (%d)", *cp);
exit(1);
}
printer = cp;
recvjob();
break;
case '\3': /* display the queue (short form) */
case '\4': /* display the queue (long form) */
printer = cp;
while (*cp) {
if (*cp != ' ') {
cp++;
continue;
}
*cp++ = '\0';
while (isspace(*cp))
cp++;
if (*cp == '\0')
break;
if (isdigit(*cp)) {
if (requests >= MAXREQUESTS)
fatal("Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal("Too many users");
user[users++] = cp;
}
}
displayq(cbuf[0] - '\3');
exit(0);
case '\5': /* remove a job from the queue */
if (!from_remote) {
syslog(LOG_INFO, "illegal request (%d)", *cp);
exit(1);
}
printer = cp;
while (*cp && *cp != ' ')
cp++;
if (!*cp)
break;
*cp++ = '\0';
person = cp;
while (*cp) {
if (*cp != ' ') {
cp++;
continue;
}
*cp++ = '\0';
while (isspace(*cp))
cp++;
if (*cp == '\0')
break;
if (isdigit(*cp)) {
if (requests >= MAXREQUESTS)
fatal("Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal("Too many users");
user[users++] = cp;
}
}
rmjob();
break;
}
fatal("Illegal service request");
}
}
/*
* Make a pass through the printcap database and start printing any
* files left from the last time the machine went down.
*/
static void
startup()
{
char *buf;
register char *cp;
int pid;
/*
* Restart the daemons.
*/
while (cgetnext(&buf, printcapdb) > 0) {
printer = buf;
for (cp = buf; *cp; cp++)
if (*cp == '|' || *cp == ':') {
*cp = '\0';
break;
}
if ((pid = fork()) < 0) {
syslog(LOG_WARNING, "startup: cannot fork");
mcleanup(0);
}
if (!pid) {
cgetclose();
printjob();
}
}
}
#define DUMMY ":nobody::"
/*
* Check to see if the from host has access to the line printer.
*/
static void
chkhost(f)
struct sockaddr_in *f;
{
register struct hostent *hp;
register FILE *hostf;
int first = 1;
extern char *inet_ntoa();
f->sin_port = ntohs(f->sin_port);
if (f->sin_family != AF_INET || f->sin_port >= IPPORT_RESERVED)
fatal("Malformed from address");
/* Need real hostname for temporary filenames */
hp = gethostbyaddr((char *)&f->sin_addr,
sizeof(struct in_addr), f->sin_family);
if (hp == NULL)
fatal("Host name for your address (%s) unknown",
inet_ntoa(f->sin_addr));
(void) strncpy(fromb, hp->h_name, sizeof(fromb));
from[sizeof(fromb) - 1] = '\0';
from = fromb;
hostf = fopen(_PATH_HOSTSEQUIV, "r");
again:
if (hostf) {
if (__ivaliduser(hostf, f->sin_addr.s_addr,
DUMMY, DUMMY) == 0) {
(void) fclose(hostf);
return;
}
(void) fclose(hostf);
}
if (first == 1) {
first = 0;
hostf = fopen(_PATH_HOSTSLPD, "r");
goto again;
}
fatal("Your host does not have line printer access");
/*NOTREACHED*/
}