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xNBA/contrib/p910nd-0.8/p910nd.c
2005-05-17 16:44:57 +00:00

421 lines
9.8 KiB
C

/*
* Port 9100+n daemon
* Accepts a connection from port 9100+n and copy stream to
* /dev/lpn, where n = 0,1,2.
*
* Run standalone as: p910nd [0|1|2]
*
* Run under inetd as:
* p910n stream tcp nowait root /usr/sbin/tcpd p910nd [0|1|2]
* where p910n is an /etc/services entry for
* port 9100, 9101 or 9102 as the case may be.
* root can be replaced by any uid with rw permission on /dev/lpn
*
* Port 9100+n will then be passively opened
* n defaults to 0
*
* Version 0.8
* Allow specifying address to bind to
*
* Version 0.7
* Bidirectional data transfer
*
* Version 0.6
* Arne Bernin fixed some cast warnings, corrected the version number
* and added a -v option to print the version.
*
* Version 0.5
* -DUSE_LIBWRAP and -lwrap enables hosts_access (tcpwrappers) checking.
*
* Version 0.4
* Ken Yap (ken_yap@users.sourceforge.net), April 2001
* Placed under GPL.
*
* Added -f switch to specify device which overrides /dev/lpn.
* But number is still required get distinct ports and locks.
*
* Added locking so that two invocations of the daemon under inetd
* don't try to open the printer at the same time. This can happen
* even if there is one host running clients because the previous
* client can exit after it has sent all data but the printer has not
* finished printing and inetd starts up a new daemon when the next
* request comes in too soon.
*
* Various things could be Linux specific. I don't
* think there is much demand for this program outside of PCs,
* but if you port it to other distributions or platforms,
* I'd be happy to receive your patches.
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <ctype.h>
#include <string.h>
#include <fcntl.h>
#include <netdb.h>
#include <syslog.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef USE_LIBWRAP
#include "tcpd.h"
int allow_severity, deny_severity;
extern int hosts_ctl(char *daemon, char *client_name,
char *client_addr, char *client_user);
#endif
#define BASEPORT 9100
#define PIDFILE "/var/run/p910%cd.pid"
#ifdef LOCKFILE_DIR
#define LOCKFILE LOCKFILE_DIR "/p910%cd"
#else
#define LOCKFILE "/var/lock/subsys/p910%cd"
#endif
#define PRINTERFILE "/dev/lp%c"
#define LOGOPTS LOG_ERR
static char *progname;
static char version[] = "p910nd Version 0.8";
static int lockfd = -1;
static char *device = 0;
static int bidir = 0;
static char *bindaddr = 0;
void usage(void)
{
fprintf(stderr, "Usage: %s [-f device] [-i bindaddr] [-bv] [0|1|2]\n", progname);
exit(1);
}
void show_version (void)
{
fprintf(stdout, "%s \n", version);
}
FILE *open_printer(int lpnumber)
{
FILE *f;
char lpname[sizeof(PRINTERFILE)];
#ifdef TESTING
(void)snprintf(lpname, sizeof(lpname), "/dev/tty");
#else
(void)snprintf(lpname, sizeof(lpname), PRINTERFILE, lpnumber);
#endif
if (device == 0)
device = lpname;
if ((f = fopen(device, bidir ? "w+" : "w")) == NULL)
{
syslog(LOGOPTS, "%s: %m\n", device);
exit(1);
}
return (f);
}
int get_lock(int lpnumber)
{
char lockname[sizeof(LOCKFILE)];
struct flock lplock;
(void)snprintf(lockname, sizeof(lockname), LOCKFILE, lpnumber);
if ((lockfd = open(lockname, O_CREAT|O_RDWR)) < 0)
{
syslog(LOGOPTS, "%s: %m\n", lockname);
return (0);
}
memset(&lplock, 0, sizeof(lplock));
lplock.l_type = F_WRLCK;
lplock.l_pid = getpid();
if (fcntl(lockfd, F_SETLKW, &lplock) < 0)
{
syslog(LOGOPTS, "%s: %m\n", lockname);
return (0);
}
return (1);
}
void free_lock(void)
{
if (lockfd >= 0)
(void)close(lockfd);
}
/* Copy network socket to FILE f until EOS */
int copy_stream(int fd, FILE *f)
{
int nread;
char buffer[8192];
if (bidir) {
FILE *nf;
if ((nf = fdopen(fd, "w")) == NULL) {
syslog(LOGOPTS, "fdopen: %m\n");
}
for (;;) {
fd_set readfds;
int result;
int maxfd = fileno(f) > fd ? fileno(f) : fd;
FD_ZERO(&readfds);
FD_SET(fileno(f), &readfds);
FD_SET(fd, &readfds);
result = select(maxfd + 1, &readfds, 0, 0, 0);
if (result < 0)
return (result);
if (result == 0)
continue;
if (FD_ISSET(fd, &readfds)) {
nread = read(fd, buffer, sizeof(buffer));
if (nread <= 0)
break;
(void)fwrite(buffer, sizeof(char), nread, f);
}
if (FD_ISSET(fileno(f), &readfds)) {
nread = read(fileno(f), buffer, sizeof(buffer));
if (nread > 0 && nf != NULL) {
(void)fwrite(buffer, sizeof(char), nread, nf);
(void)fflush(nf);
}
}
}
(void)fflush(f);
(void)fclose(nf);
return (0);
} else {
while ((nread = read(fd, buffer, sizeof(buffer))) > 0)
(void)fwrite(buffer, sizeof(char), nread, f);
(void)fflush(f);
return (nread);
}
}
void one_job(int lpnumber)
{
FILE *f;
struct sockaddr_in client;
socklen_t clientlen = sizeof(client);
if (getpeername(0, (struct sockaddr*) &client, &clientlen) >= 0)
syslog(LOGOPTS, "Connection from %s port %hu\n",
inet_ntoa(client.sin_addr),
ntohs(client.sin_port));
if (get_lock(lpnumber) == 0)
return;
f = open_printer(lpnumber);
if (copy_stream(0, f) < 0)
syslog(LOGOPTS, "copy_stream: %m\n");
fclose(f);
free_lock();
}
void server(int lpnumber)
{
struct rlimit resourcelimit;
#ifdef USE_GETPROTOBYNAME
struct protoent *proto;
#endif
int netfd, fd, one = 1;
socklen_t clientlen;
struct sockaddr_in netaddr, client;
char pidfilename[sizeof(PIDFILE)];
FILE *f;
int ipret;
#ifndef TESTING
switch (fork())
{
case -1:
syslog(LOGOPTS, "fork: %m\n");
exit (1);
case 0: /* child */
break;
default: /* parent */
exit(0);
}
/* Now in child process */
resourcelimit.rlim_max = 0;
if (getrlimit(RLIMIT_NOFILE, &resourcelimit) < 0)
{
syslog(LOGOPTS, "getrlimit: %m\n");
exit(1);
}
for (fd = 0; fd < resourcelimit.rlim_max; ++fd)
(void)close(fd);
if (setsid() < 0)
{
syslog(LOGOPTS, "setsid: %m\n");
exit(1);
}
(void)chdir("/");
(void)umask(022);
fd = open("/dev/null", O_RDWR); /* stdin */
(void)dup(fd); /* stdout */
(void)dup(fd); /* stderr */
(void)snprintf(pidfilename, sizeof(pidfilename), PIDFILE, lpnumber);
if ((f = fopen(pidfilename, "w")) == NULL)
{
syslog(LOGOPTS, "%s: %m\n", pidfilename);
exit(1);
}
(void)fprintf(f, "%d\n", getpid());
(void)fclose(f);
if (get_lock(lpnumber) == 0)
exit(1);
#endif
f = open_printer(lpnumber);
#ifdef USE_GETPROTOBYNAME
if ((proto = getprotobyname("tcp")) == NULL)
{
syslog(LOGOPTS, "Cannot find protocol for TCP!\n");
exit(1);
}
if ((netfd = socket(AF_INET, SOCK_STREAM, proto->p_proto)) < 0)
#else
if ((netfd = socket(AF_INET, SOCK_STREAM, IPPROTO_IP)) < 0)
#endif
{
syslog(LOGOPTS, "socket: %m\n");
exit(1);
}
if (setsockopt(netfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
{
syslog(LOGOPTS, "setsocketopt: %m\n");
exit(1);
}
netaddr.sin_port = htons(BASEPORT + lpnumber - '0');
if (bindaddr == 0) {
netaddr.sin_addr.s_addr = htonl(INADDR_ANY);
} else {
ipret = inet_pton(AF_INET, bindaddr, &netaddr.sin_addr.s_addr);
if (ipret < 0) {
syslog(LOGOPTS, "inet_pton: %m\n");
exit(1);
} else if (ipret == 0) {
syslog(LOGOPTS, "inet_pton: invalid bind IP address\n");
exit(1);
}
}
memset(netaddr.sin_zero, 0, sizeof(netaddr.sin_zero));
if (bind(netfd, (struct sockaddr*) &netaddr, sizeof(netaddr)) < 0)
{
syslog(LOGOPTS, "bind: %m\n");
exit(1);
}
if (listen(netfd, 5) < 0)
{
syslog(LOGOPTS, "listen: %m\n");
exit(1);
}
clientlen = sizeof(client);
memset(&client, 0, sizeof(client));
while ((fd = accept(netfd, (struct sockaddr*) &client, &clientlen)) >= 0)
{
#ifdef USE_LIBWRAP
if (hosts_ctl("p910nd", STRING_UNKNOWN,
inet_ntoa(client.sin_addr), STRING_UNKNOWN) == 0) {
syslog(LOGOPTS, "Connection from %s port %hd rejected\n",
inet_ntoa(client.sin_addr),
ntohs(client.sin_port));
close(fd);
continue;
}
#endif
syslog(LOGOPTS, "Connection from %s port %hd accepted\n",
inet_ntoa(client.sin_addr),
ntohs(client.sin_port));
/*write(fd, "Printing", 8);*/
if (copy_stream(fd, f) < 0)
syslog(LOGOPTS, "copy_stream: %m\n");
(void)close(fd);
}
syslog(LOGOPTS, "accept: %m\n");
free_lock();
exit(1);
}
int is_standalone(void)
{
struct sockaddr_in bind_addr;
socklen_t ba_len;
/*
* Check to see if a socket was passed to us from inetd.
*
* Use getsockname() to determine if descriptor 0 is indeed a socket
* (and thus we are probably a child of inetd) or if it is instead
* something else and we are running standalone.
*/
ba_len = sizeof(bind_addr);
if (getsockname(0, (struct sockaddr*) &bind_addr, &ba_len) == 0)
return (0); /* under inetd */
if (errno != ENOTSOCK) /* strange... */
syslog(LOGOPTS, "getsockname: %m\n");
return (1);
}
int main(int argc, char *argv[])
{
int c, lpnumber;
char *p;
if (argc <= 0) /* in case not provided in inetd.conf */
progname = "p910nd";
else
{
progname = argv[0];
if ((p = strrchr(progname, '/')) != 0)
progname = p + 1;
}
lpnumber = '0';
while ((c = getopt(argc, argv, "bi:f:v")) != EOF)
{
switch (c)
{
case 'b':
bidir = 1;
break;
case 'f':
device = optarg;
break;
case 'i':
bindaddr = optarg;
break;
case 'v':
show_version();
break;
default:
usage();
break;
}
}
argc -= optind;
argv += optind;
if (argc > 0)
{
if (isdigit(argv[0][0]))
lpnumber = argv[0][0];
}
/* change the n in argv[0] to match the port so ps will show that */
if ((p = strstr(progname, "p910n")) != NULL)
p[4] = lpnumber;
/* We used to pass (LOG_PERROR|LOG_PID|LOG_LPR|LOG_ERR) to syslog, but
* syslog ignored the LOG_PID and LOG_PERROR option. I.e. the intention
* was to add both options but the effect was to have neither.
* I disagree with the intention to add PERROR. --Stef */
openlog (p, LOG_PID, LOG_LPR);
if (is_standalone())
server(lpnumber);
else
one_job(lpnumber);
return (0);
}