4.3BSD/usr/src/usr.lib/lpr/lpd.c
/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1983 Regents of the University of California.\n\
All rights reserved.\n";
#endif not lint
#ifndef lint
static char sccsid[] = "@(#)lpd.c 5.4 (Berkeley) 5/6/86";
#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 "lp.h"
int lflag; /* log requests flag */
int reapchild();
int mcleanup();
main(argc, argv)
int argc;
char **argv;
{
int f, funix, finet, options, defreadfds, fromlen;
struct sockaddr_un sun, fromunix;
struct sockaddr_in sin, frominet;
int omask, lfd;
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.
*/
if (fork())
exit(0);
for (f = 0; f < 5; f++)
(void) close(f);
(void) open("/dev/null", O_RDONLY);
(void) open("/dev/null", O_WRONLY);
(void) dup(1);
f = open("/dev/tty", O_RDWR);
if (f > 0) {
ioctl(f, TIOCNOTTY, 0);
(void) close(f);
}
#endif
openlog("lpd", LOG_PID, LOG_LPR);
(void) umask(0);
lfd = open(MASTERLOCK, O_WRONLY|O_CREAT, 0644);
if (lfd < 0) {
syslog(LOG_ERR, "%s: %m", MASTERLOCK);
exit(1);
}
if (flock(lfd, LOCK_EX|LOCK_NB) < 0) {
if (errno == EWOULDBLOCK) /* active deamon present */
exit(0);
syslog(LOG_ERR, "%s: %m", 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", MASTERLOCK);
exit(1);
}
signal(SIGCHLD, reapchild);
/*
* Restart all the printers.
*/
startup();
(void) unlink(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);
sun.sun_family = AF_UNIX;
strcpy(sun.sun_path, SOCKETNAME);
if (bind(funix, &sun, strlen(sun.sun_path) + 2) < 0) {
syslog(LOG_ERR, "ubind: %m");
exit(1);
}
sigsetmask(omask);
defreadfds = 1 << funix;
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();
}
sp = getservbyname("printer", "tcp");
if (sp == NULL) {
syslog(LOG_ERR, "printer/tcp: unknown service");
mcleanup();
}
sin.sin_family = AF_INET;
sin.sin_port = sp->s_port;
if (bind(finet, &sin, sizeof(sin), 0) < 0) {
syslog(LOG_ERR, "bind: %m");
mcleanup();
}
defreadfds |= 1 << finet;
listen(finet, 5);
}
/*
* Main loop: accept, do a request, continue.
*/
for (;;) {
int domain, nfds, s, readfds = defreadfds;
nfds = select(20, &readfds, 0, 0, 0);
if (nfds <= 0) {
if (nfds < 0 && errno != EINTR)
syslog(LOG_WARNING, "select: %m");
continue;
}
if (readfds & (1 << funix)) {
domain = AF_UNIX, fromlen = sizeof(fromunix);
s = accept(funix, &fromunix, &fromlen);
} else if (readfds & (1 << finet)) {
domain = AF_INET, fromlen = sizeof(frominet);
s = accept(finet, &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)
chkhost(&frominet);
doit();
exit(0);
}
(void) close(s);
}
}
reapchild()
{
union wait status;
while (wait3(&status, WNOHANG, 0) > 0)
;
}
mcleanup()
{
if (lflag)
syslog(LOG_INFO, "exiting");
unlink(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[32]; /* buffer for client's machine name */
char cbuf[BUFSIZ]; /* command line buffer */
char *cmdnames[] = {
"null",
"printjob",
"recvjob",
"displayq short",
"displayq long",
"rmjob"
};
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 */
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 */
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.
*/
startup()
{
char buf[BUFSIZ];
register char *cp;
int pid;
printer = buf;
/*
* Restart the daemons.
*/
while (getprent(buf) > 0) {
for (cp = buf; *cp; cp++)
if (*cp == '|' || *cp == ':') {
*cp = '\0';
break;
}
if ((pid = fork()) < 0) {
syslog(LOG_WARNING, "startup: cannot fork");
mcleanup();
}
if (!pid) {
endprent();
printjob();
}
}
}
#define DUMMY ":nobody::"
/*
* Check to see if the from host has access to the line printer.
*/
chkhost(f)
struct sockaddr_in *f;
{
register struct hostent *hp;
register FILE *hostf;
register char *cp, *sp;
char ahost[50];
int first = 1;
extern char *inet_ntoa();
int baselen = -1;
f->sin_port = ntohs(f->sin_port);
if (f->sin_family != AF_INET || f->sin_port >= IPPORT_RESERVED)
fatal("Malformed from address");
hp = gethostbyaddr(&f->sin_addr, sizeof(struct in_addr), f->sin_family);
if (hp == 0)
fatal("Host name for your address (%s) unknown",
inet_ntoa(f->sin_addr));
strcpy(fromb, hp->h_name);
from = fromb;
if (!strcmp(from, host))
return;
sp = fromb;
cp = ahost;
while (*sp) {
if (*sp == '.') {
if (baselen == -1)
baselen = sp - fromb;
*cp++ = *sp++;
} else {
*cp++ = isupper(*sp) ? tolower(*sp++) : *sp++;
}
}
*cp = '\0';
hostf = fopen("/etc/hosts.equiv", "r");
again:
if (hostf) {
if (!_validuser(hostf, ahost, DUMMY, DUMMY, baselen)) {
(void) fclose(hostf);
return;
}
(void) fclose(hostf);
}
if (first == 1) {
first = 0;
hostf = fopen("/etc/hosts.lpd", "r");
goto again;
}
fatal("Your host does not have line printer access");
}