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freebsd-dev/usr.sbin/lpr/lpd/lpd.c
Philippe Charnier 54ede02d10 add FBSDID
2003-07-06 12:44:11 +00:00

947 lines
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/*
* Copyright (c) 1983, 1993, 1994
* 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 const char copyright[] =
"@(#) Copyright (c) 1983, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#if 0
#ifndef lint
static char sccsid[] = "@(#)lpd.c 8.7 (Berkeley) 5/10/95";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* 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 <sys/file.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <syslog.h>
#include <signal.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <ctype.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"
#include "extern.h"
int lflag; /* log requests flag */
int sflag; /* no incoming port flag */
int from_remote; /* from remote socket */
int main(int argc, char **_argv);
static void reapchild(int _signo);
static void mcleanup(int _signo);
static void doit(void);
static void startup(void);
static void chkhost(struct sockaddr *_f, int _ch_opts);
static int ckqueue(struct printer *_pp);
static void fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg);
static int *socksetup(int _af, int _debuglvl);
static void usage(void);
/* XXX from libc/net/rcmd.c */
extern int __ivaliduser_sa __P((FILE *, struct sockaddr *, socklen_t,
const char *, const char *));
uid_t uid, euid;
#define LPD_NOPORTCHK 0001 /* skip reserved-port check */
#define LPD_LOGCONNERR 0002 /* (sys)log connection errors */
#define LPD_ADDFROMLINE 0004 /* just used for fhosterr() */
int
main(int argc, char **argv)
{
int ch_options, errs, f, funix, *finet, i, lfd, socket_debug;
fd_set defreadfds;
struct sockaddr_un un, fromunix;
struct sockaddr_storage frominet;
socklen_t fromlen;
sigset_t omask, nmask;
struct servent *sp, serv;
int inet_flag = 0, inet6_flag = 0;
euid = geteuid(); /* these shouldn't be different */
uid = getuid();
ch_options = 0;
socket_debug = 0;
gethostname(local_host, sizeof(local_host));
progname = "lpd";
if (euid != 0)
errx(EX_NOPERM,"must run as root");
errs = 0;
while ((i = getopt(argc, argv, "cdlpswW46")) != -1)
switch (i) {
case 'c':
/* log all kinds of connection-errors to syslog */
ch_options |= LPD_LOGCONNERR;
break;
case 'd':
socket_debug++;
break;
case 'l':
lflag++;
break;
case 'p': /* letter initially used for -s */
/*
* This will probably be removed with 5.0-release.
*/
/* FALLTHROUGH */
case 's': /* secure (no inet) */
sflag++;
break;
case 'w': /* netbsd uses -w for maxwait */
/*
* This will be removed after the release of 4.4, as
* it conflicts with -w in netbsd's lpd. For now it
* is just a warning, so we won't suddenly break lpd
* for anyone who is currently using the option.
*/
syslog(LOG_WARNING,
"NOTE: the -w option has been renamed -W");
syslog(LOG_WARNING,
"NOTE: please change your lpd config to use -W");
/* FALLTHROUGH */
case 'W':
/* allow connections coming from a non-reserved port */
/* (done by some lpr-implementations for MS-Windows) */
ch_options |= LPD_NOPORTCHK;
break;
case '4':
family = PF_INET;
inet_flag++;
break;
case '6':
#ifdef INET6
family = PF_INET6;
inet6_flag++;
#else
errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)");
#endif
break;
/*
* The following options are not in FreeBSD (yet?), but are
* listed here to "reserve" them, because the option-letters
* are used by either NetBSD or OpenBSD (as of July 2001).
*/
case 'b': /* set bind-addr */
case 'n': /* set max num of children */
case 'r': /* allow 'of' for remote ptrs */
/* ...[not needed in freebsd] */
/* FALLTHROUGH */
default:
errs++;
}
if (inet_flag && inet6_flag)
family = PF_UNSPEC;
argc -= optind;
argv += optind;
if (errs)
usage();
if (argc == 1) {
if ((i = atoi(argv[0])) == 0)
usage();
if (i < 0 || i > USHRT_MAX)
errx(EX_USAGE, "port # %d is invalid", i);
serv.s_port = htons(i);
sp = &serv;
argc--;
} else {
sp = getservbyname("printer", "tcp");
if (sp == NULL)
errx(EX_OSFILE, "printer/tcp: unknown service");
}
if (argc != 0)
usage();
/*
* We run chkprintcap right away to catch any errors and blat them
* to stderr while we still have it open, rather than sending them
* to syslog and leaving the user wondering why lpd started and
* then stopped. There should probably be a command-line flag to
* ignore errors from chkprintcap.
*/
{
pid_t pid;
int status;
pid = fork();
if (pid < 0) {
err(EX_OSERR, "cannot fork");
} else if (pid == 0) { /* child */
execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0);
err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP);
}
if (waitpid(pid, &status, 0) < 0) {
err(EX_OSERR, "cannot wait");
}
if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
errx(EX_OSFILE, "%d errors in printcap file, exiting",
WEXITSTATUS(status));
}
#ifndef DEBUG
/*
* Set up standard environment by detaching from the parent.
*/
daemon(0, 0);
#endif
openlog("lpd", LOG_PID, LOG_LPR);
syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag,
socket_debug ? " dbg" : "", sflag ? " net-secure" : "");
(void) umask(0);
/*
* NB: This depends on O_NONBLOCK semantics doing the right thing;
* i.e., applying only to the O_EXLOCK and not to the rest of the
* open/creation. As of 1997-12-02, this is the case for commonly-
* used filesystems. There are other places in this code which
* make the same assumption.
*/
lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK,
LOCK_FILE_MODE);
if (lfd < 0) {
if (errno == EWOULDBLOCK) /* active daemon present */
exit(0);
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
fcntl(lfd, F_SETFL, 0); /* turn off non-blocking mode */
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);
}
sigemptyset(&nmask);
sigaddset(&nmask, SIGHUP);
sigaddset(&nmask, SIGINT);
sigaddset(&nmask, SIGQUIT);
sigaddset(&nmask, SIGTERM);
sigprocmask(SIG_BLOCK, &nmask, &omask);
(void) umask(07);
signal(SIGHUP, mcleanup);
signal(SIGINT, mcleanup);
signal(SIGQUIT, mcleanup);
signal(SIGTERM, mcleanup);
memset(&un, 0, sizeof(un));
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);
}
(void) umask(0);
sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
FD_ZERO(&defreadfds);
FD_SET(funix, &defreadfds);
listen(funix, 5);
if (sflag == 0) {
finet = socksetup(family, socket_debug);
} else
finet = NULL; /* pretend we couldn't open TCP socket. */
if (finet) {
for (i = 1; i <= *finet; i++) {
FD_SET(finet[i], &defreadfds);
listen(finet[i], 5);
}
}
/*
* Main loop: accept, do a request, continue.
*/
memset(&frominet, 0, sizeof(frominet));
memset(&fromunix, 0, sizeof(fromunix));
if (lflag)
syslog(LOG_INFO, "lpd startup: ready to accept requests");
/*
* XXX - should be redone for multi-protocol
*/
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;
}
domain = -1; /* avoid compile-time warning */
s = -1; /* avoid compile-time warning */
if (FD_ISSET(funix, &readfds)) {
domain = AF_UNIX, fromlen = sizeof(fromunix);
s = accept(funix,
(struct sockaddr *)&fromunix, &fromlen);
} else {
for (i = 1; i <= *finet; i++)
if (FD_ISSET(finet[i], &readfds)) {
domain = AF_INET;
fromlen = sizeof(frominet);
s = accept(finet[i],
(struct sockaddr *)&frominet,
&fromlen);
}
}
if (s < 0) {
if (errno != EINTR)
syslog(LOG_WARNING, "accept: %m");
continue;
}
if (fork() == 0) {
/*
* Note that printjob() also plays around with
* signal-handling routines, and may need to be
* changed when making changes to signal-handling.
*/
signal(SIGCHLD, SIG_DFL);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
(void) close(funix);
if (sflag == 0 && finet) {
for (i = 1; i <= *finet; i++)
(void)close(finet[i]);
}
dup2(s, 1);
(void) close(s);
if (domain == AF_INET) {
/* for both AF_INET and AF_INET6 */
from_remote = 1;
chkhost((struct sockaddr *)&frominet,
ch_options);
} else
from_remote = 0;
doit();
exit(0);
}
(void) close(s);
}
}
static void
reapchild(int signo __unused)
{
int status;
while (wait3(&status, WNOHANG, 0) > 0)
;
}
static void
mcleanup(int signo)
{
/*
* XXX syslog(3) is not signal-safe.
*/
if (lflag) {
if (signo)
syslog(LOG_INFO, "exiting on signal %d", signo);
else
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 */
/* buffer to hold the client's machine-name */
static char frombuf[MAXHOSTNAMELEN];
char cbuf[BUFSIZ]; /* command line buffer */
const char *cmdnames[] = {
"null",
"printjob",
"recvjob",
"displayq short",
"displayq long",
"rmjob"
};
static void
doit(void)
{
char *cp, *printer;
int n;
int status;
struct printer myprinter, *pp = &myprinter;
init_printer(&myprinter);
for (;;) {
cp = cbuf;
do {
if (cp >= &cbuf[sizeof(cbuf) - 1])
fatal(0, "Command line too long");
if ((n = read(STDOUT_FILENO, cp, 1)) != 1) {
if (n < 0)
fatal(0, "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_host, cmdnames[(u_char)*cp], cp+1);
else
syslog(LOG_INFO, "bad request (%d) from %s",
*cp, from_host);
}
switch (*cp++) {
case CMD_CHECK_QUE: /* check the queue, print any jobs there */
startprinting(cp);
break;
case CMD_TAKE_THIS: /* receive files to be queued */
if (!from_remote) {
syslog(LOG_INFO, "illegal request (%d)", *cp);
exit(1);
}
recvjob(cp);
break;
case CMD_SHOWQ_SHORT: /* display the queue (short form) */
case CMD_SHOWQ_LONG: /* display the queue (long form) */
/* XXX - this all needs to be redone. */
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(0, "Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal(0, "Too many users");
user[users++] = cp;
}
}
status = getprintcap(printer, pp);
if (status < 0)
fatal(pp, "%s", pcaperr(status));
displayq(pp, cbuf[0] == CMD_SHOWQ_LONG);
exit(0);
case CMD_RMJOB: /* 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(0, "Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal(0, "Too many users");
user[users++] = cp;
}
}
rmjob(printer);
break;
}
fatal(0, "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(void)
{
int pid, status, more;
struct printer myprinter, *pp = &myprinter;
more = firstprinter(pp, &status);
if (status)
goto errloop;
while (more) {
if (ckqueue(pp) <= 0) {
goto next;
}
if (lflag)
syslog(LOG_INFO, "lpd startup: work for %s",
pp->printer);
if ((pid = fork()) < 0) {
syslog(LOG_WARNING, "lpd startup: cannot fork for %s",
pp->printer);
mcleanup(0);
}
if (pid == 0) {
lastprinter();
printjob(pp);
/* NOTREACHED */
}
do {
next:
more = nextprinter(pp, &status);
errloop:
if (status)
syslog(LOG_WARNING,
"lpd startup: printcap entry for %s has errors, skipping",
pp->printer ? pp->printer : "<noname?>");
} while (more && status);
}
}
/*
* Make sure there's some work to do before forking off a child
*/
static int
ckqueue(struct printer *pp)
{
register struct dirent *d;
DIR *dirp;
char *spooldir;
spooldir = pp->spool_dir;
if ((dirp = opendir(spooldir)) == NULL)
return (-1);
while ((d = readdir(dirp)) != NULL) {
if (d->d_name[0] != 'c' || d->d_name[1] != 'f')
continue; /* daemon control files only */
closedir(dirp);
return (1); /* found something */
}
closedir(dirp);
return (0);
}
#define DUMMY ":nobody::"
/*
* Check to see if the host connecting to this host has access to any
* lpd services on this host.
*/
static void
chkhost(struct sockaddr *f, int ch_opts)
{
struct addrinfo hints, *res, *r;
register FILE *hostf;
char hostbuf[NI_MAXHOST], ip[NI_MAXHOST];
char serv[NI_MAXSERV];
char *syserr, *usererr;
int error, errsav, fpass, good, wantsl;
wantsl = 0;
if (ch_opts & LPD_LOGCONNERR)
wantsl = 1; /* also syslog the errors */
from_host = ".na.";
/* Need real hostname for temporary filenames */
error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
NI_NAMEREQD);
if (error) {
errsav = error;
error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf),
NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID);
if (error) {
asprintf(&syserr,
"can not determine hostname for remote host (%d,%d)",
errsav, error);
asprintf(&usererr,
"Host name for your address is not known");
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
}
asprintf(&syserr,
"Host name for remote host (%s) not known (%d)",
hostbuf, errsav);
asprintf(&usererr,
"Host name for your address (%s) is not known",
hostbuf);
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
}
strlcpy(frombuf, hostbuf, sizeof(frombuf));
from_host = frombuf;
ch_opts |= LPD_ADDFROMLINE;
/* Need address in stringform for comparison (no DNS lookup here) */
error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
NI_NUMERICHOST | NI_WITHSCOPEID);
if (error) {
asprintf(&syserr, "Cannot print IP address (error %d)",
error);
asprintf(&usererr, "Cannot print IP address for your host");
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
}
from_ip = strdup(hostbuf);
/* Reject numeric addresses */
memset(&hints, 0, sizeof(hints));
hints.ai_family = family;
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
if (getaddrinfo(from_host, NULL, &hints, &res) == 0) {
freeaddrinfo(res);
/* This syslog message already includes from_host */
ch_opts &= ~LPD_ADDFROMLINE;
asprintf(&syserr, "reverse lookup results in non-FQDN %s",
from_host);
/* same message to both syslog and remote user */
fhosterr(ch_opts, syserr, syserr);
/* NOTREACHED */
}
/* Check for spoof, ala rlogind */
memset(&hints, 0, sizeof(hints));
hints.ai_family = family;
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
error = getaddrinfo(from_host, NULL, &hints, &res);
if (error) {
asprintf(&syserr, "dns lookup for address %s failed: %s",
from_ip, gai_strerror(error));
asprintf(&usererr, "hostname for your address (%s) unknown: %s",
from_ip, gai_strerror(error));
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
}
good = 0;
for (r = res; good == 0 && r; r = r->ai_next) {
error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip),
NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID);
if (!error && !strcmp(from_ip, ip))
good = 1;
}
if (res)
freeaddrinfo(res);
if (good == 0) {
asprintf(&syserr, "address for remote host (%s) not matched",
from_ip);
asprintf(&usererr,
"address for your hostname (%s) not matched", from_ip);
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
}
fpass = 1;
hostf = fopen(_PATH_HOSTSEQUIV, "r");
again:
if (hostf) {
if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) {
(void) fclose(hostf);
goto foundhost;
}
(void) fclose(hostf);
}
if (fpass == 1) {
fpass = 2;
hostf = fopen(_PATH_HOSTSLPD, "r");
goto again;
}
/* This syslog message already includes from_host */
ch_opts &= ~LPD_ADDFROMLINE;
asprintf(&syserr, "refused connection from %s, sip=%s", from_host,
from_ip);
asprintf(&usererr,
"Print-services are not available to your host (%s).", from_host);
fhosterr(ch_opts, syserr, usererr);
/* NOTREACHED */
foundhost:
if (ch_opts & LPD_NOPORTCHK)
return; /* skip the reserved-port check */
error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv),
NI_NUMERICSERV);
if (error) {
/* same message to both syslog and remote user */
asprintf(&syserr, "malformed from-address (%d)", error);
fhosterr(ch_opts, syserr, syserr);
/* NOTREACHED */
}
if (atoi(serv) >= IPPORT_RESERVED) {
/* same message to both syslog and remote user */
asprintf(&syserr, "connected from invalid port (%s)", serv);
fhosterr(ch_opts, syserr, syserr);
/* NOTREACHED */
}
}
/*
* Handle fatal errors in chkhost. The first message will optionally be
* sent to syslog, the second one is sent to the connecting host.
*
* The idea is that the syslog message is meant for an administrator of a
* print server (the host receiving connections), while the usermsg is meant
* for a remote user who may or may not be clueful, and may or may not be
* doing something nefarious. Some remote users (eg, MS-Windows...) may not
* even see whatever message is sent, which is why there's the option to
* start 'lpd' with the connection-errors also sent to syslog.
*
* Given that hostnames can theoretically be fairly long (well, over 250
* bytes), it would probably be helpful to have the 'from_host' field at
* the end of any error messages which include that info.
*
* These are Fatal host-connection errors, so this routine does not return.
*/
static void
fhosterr(int ch_opts, char *sysmsg, char *usermsg)
{
/*
* If lpd was started up to print connection errors, then write
* the syslog message before the user message.
* And for many of the syslog messages, it is helpful to first
* write the from_host (if it is known) as a separate syslog
* message, since the hostname may be so long.
*/
if (ch_opts & LPD_LOGCONNERR) {
if (ch_opts & LPD_ADDFROMLINE) {
syslog(LOG_WARNING, "for connection from %s:", from_host);
}
syslog(LOG_WARNING, "%s", sysmsg);
}
/*
* Now send the error message to the remote host which is trying
* to make the connection.
*/
printf("%s [@%s]: %s\n", progname, local_host, usermsg);
fflush(stdout);
/*
* Add a minimal delay before exiting (and disconnecting from the
* sending-host). This is just in case that machine responds by
* INSTANTLY retrying (and instantly re-failing...). This may also
* give the other side more time to read the error message.
*/
sleep(2); /* a paranoid throttling measure */
exit(1);
}
/* setup server socket for specified address family */
/* if af is PF_UNSPEC more than one socket may be returned */
/* the returned list is dynamically allocated, so caller needs to free it */
static int *
socksetup(int af, int debuglvl)
{
struct addrinfo hints, *res, *r;
int error, maxs, *s, *socks;
const int on = 1;
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_PASSIVE;
hints.ai_family = af;
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo(NULL, "printer", &hints, &res);
if (error) {
syslog(LOG_ERR, "%s", gai_strerror(error));
mcleanup(0);
}
/* Count max number of sockets we may open */
for (maxs = 0, r = res; r; r = r->ai_next, maxs++)
;
socks = malloc((maxs + 1) * sizeof(int));
if (!socks) {
syslog(LOG_ERR, "couldn't allocate memory for sockets");
mcleanup(0);
}
*socks = 0; /* num of sockets counter at start of array */
s = socks + 1;
for (r = res; r; r = r->ai_next) {
*s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
if (*s < 0) {
syslog(LOG_DEBUG, "socket(): %m");
continue;
}
if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))
< 0) {
syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
close(*s);
continue;
}
if (debuglvl)
if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl,
sizeof(debuglvl)) < 0) {
syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
close(*s);
continue;
}
if (r->ai_family == AF_INET6) {
if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY,
&on, sizeof(on)) < 0) {
syslog(LOG_ERR,
"setsockopt (IPV6_V6ONLY): %m");
close(*s);
continue;
}
}
if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) {
syslog(LOG_DEBUG, "bind(): %m");
close(*s);
continue;
}
(*socks)++;
s++;
}
if (res)
freeaddrinfo(res);
if (*socks == 0) {
syslog(LOG_ERR, "Couldn't bind to any socket");
free(socks);
mcleanup(0);
}
return(socks);
}
static void
usage(void)
{
#ifdef INET6
fprintf(stderr, "usage: lpd [-cdlsW46] [port#]\n");
#else
fprintf(stderr, "usage: lpd [-cdlsW] [port#]\n");
#endif
exit(EX_USAGE);
}
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