4.3BSD/usr/contrib/mh/support/pop/smtpd.c
/* smtpd.c - the stub SMTP server for POP client hosts */
/* Author: Marshall T. Rose <MRose@NRTC> (MTR)
Northrop Research and Technology Center
One Research park
Palos Verdes Peninsula, CA 90274
213/377-4811
Date: Wed May 15 00:04:12 1985
*/
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <strings.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#define NOTOK (-1)
#define OK 0
/* */
extern int errno;
extern char *sys_siglist[];
int debug = 0;
static int nbits = ((sizeof (int)) * 8);
static int options = 0;
char *myname = "smtpd";
char myhost[BUFSIZ];
static char *myprotocol = "tcp";
static char *myservice = "smtp";
static struct sockaddr_in in_socket;
static struct sockaddr_in *isock = &in_socket;
static char *smtphost;
static struct sockaddr_in sm_socket;
static struct sockaddr_in *msock = &sm_socket;
void chldser ();
void adios (), advise ();
/* */
/* ARGSUSED */
main (argc, argv, envp)
int argc;
char **argv,
**envp;
{
int fd,
sd;
struct servent *sp;
struct sockaddr_in out_socket,
*osock = &out_socket;
if ((sp = getservbyname (myservice, myprotocol)) == NULL)
adios (NULL, "%s/%s: unknown service", myprotocol, myservice);
isock -> sin_family = AF_INET;
isock -> sin_port = sp -> s_port;
isock -> sin_addr.s_addr = INADDR_ANY;
arginit (argv);
envinit ();
msock -> sin_port = isock -> sin_port;
#ifdef RESTART
for (;;) {
char reason[BUFSIZ];
union wait status;
switch (fork ()) {
case NOTOK:
sleep (5);
continue;
case OK:
break;
default:
sleep (60);
(void) wait3 (&status, 0, NULL);
if (WIFEXITED (status))
(void) sprintf (reason, "exit=0%o", status.w_retcode);
else
if (WIFSIGNALED (status))
(void) sprintf (reason, "signal=%s%s",
status.w_termsig < NSIG
? sys_siglist[status.w_termsig] : "unknown",
status.w_coredump ? " (core dumped)" : NULL);
else
(void) strcpy (reason, "stopped(!!)");
advise (NULL, LOG_WARNING, "%s/%s server has terminated -- %s",
sp -> s_proto, sp -> s_name, reason);
continue;
}
break;
}
closelog ();
openlog (myname, LOG_PID);
advise (NULL, LOG_INFO, "restart");
#endif RESTART
/* */
if ((sd = socket (AF_INET, SOCK_STREAM, 0)) == NOTOK)
adios ("socket", "unable to create");
if (options & SO_DEBUG)
if (setsockopt (sd, SOL_SOCKET, SO_DEBUG, NULL, 0) == NOTOK)
advise ("SO_DEBUG", LOG_WARNING, "unable to set socket option");
if (setsockopt (sd, SOL_SOCKET, SO_KEEPALIVE, NULL, 0) == NOTOK)
advise ("SO_KEEPALIVE", LOG_WARNING, "unable to set socket option");
if (bind (sd, isock, sizeof *isock) == NOTOK)
adios ("socket", "unable to bind");
(void) signal (SIGCHLD, chldser);
(void) listen (sd, SOMAXCONN);
for (;;) {
int i = sizeof *osock;
if ((fd = accept (sd, osock, &i)) == NOTOK) {
if (errno != EINTR)
advise ("socket", LOG_WARNING,
"unable to accept connection on");
continue;
}
switch (fork ()) {
case OK:
(void) close (sd);
(void) signal (SIGCHLD, SIG_DFL);
server (fd, osock);
_exit (0);
case NOTOK:
advise ("socket", LOG_WARNING,
"no forks, so rejecting connection on");
default:
(void) close (fd);
}
}
}
/* */
static server (fd, sin)
int fd;
struct sockaddr_in *sin;
{
int sd;
u_short port;
char buffer[BUFSIZ];
struct hostent *hp;
struct in_addr *addr;
closelog ();
openlog (myname, LOG_PID);
port = ntohs (sin -> sin_port);
addr = &sin -> sin_addr;
advise (NULL, LOG_INFO, "servicing %s/%d",
(hp = gethostbyaddr (addr, sizeof *addr, sin -> sin_family))
? hp -> h_name : inet_ntoa (*addr), port);
if ((sd = socket (AF_INET, SOCK_STREAM, 0)) == NOTOK
|| connect (sd, msock, sizeof *msock) == NOTOK) {
advise (smtphost, LOG_WARNING,
sd != NOTOK ? "unable to connect to" : "socket failed for");
sprintf (buffer, "451 No %s/%s service available, try %s--%s\r\n",
myprotocol, myservice, smtphost, "you might get lucky");
write (fd, buffer, strlen (buffer));
return;
}
advise (NULL, LOG_INFO, "connected to %s", smtphost);
shuffle (fd, sd);
}
/* */
shuffle (fd, sd)
int fd,
sd;
{
int cc,
ibits,
obits,
on,
scc,
fcc;
char *sbp,
sibuf[BUFSIZ],
*fbp,
fibuf[BUFSIZ];
on = 1;
ioctl (fd, FIONBIO, &on);
ioctl (sd, FIONBIO, &on);
for (fcc = scc = 0;;) {
ibits = obits = 0;
if (fcc)
obits |= 1 << sd;
else
ibits |= 1 << fd;
if (scc)
obits |= 1 << fd;
else
ibits |= 1 << sd;
if (fcc < 0 && scc < 0)
break;
select (nbits, &ibits, &obits, NULL, NULL);
if (ibits == 0 && obits == 0) {
sleep (5);
continue;
}
if (ibits & (1 << fd)) {
fcc = read (fd, fibuf, sizeof fibuf);
if (fcc < 0 && errno == EWOULDBLOCK)
fcc = 0;
else {
if (fcc <= 0)
break;
fbp = fibuf;
}
}
if (ibits & (1 << sd)) {
scc = read (sd, sibuf, sizeof sibuf);
if (scc < 0 && errno == EWOULDBLOCK)
scc = 0;
else {
if (scc <= 0)
break;
sbp = sibuf;
}
}
if ((obits & (1 << fd)) && scc > 0) {
cc = write (fd, sbp, scc);
if (cc > 0)
scc -= cc, sbp += cc;
}
if ((obits & (1 << sd)) && fcc > 0) {
cc = write (sd, fbp, fcc);
if (cc > 0)
fcc -= cc, fbp += cc;
}
}
advise (NULL, LOG_INFO, "terminating: fcc=%d scc=%d errno=%d",
fcc, scc, errno);
}
/* */
/* set options and isock -> sin_port here... */
static arginit (vec)
char **vec;
{
struct hostent *hp;
if (myname = rindex (*vec, '/'))
myname++;
if (myname == NULL || *myname == NULL)
myname = *vec;
(void) gethostname (myhost, sizeof myhost);
if (hp = gethostbyname (myhost))
(void) strcpy (myhost, hp -> h_name);
nbits = getdtablesize ();
if ((smtphost = *++vec) == NULL)
adios (NULL, "usage: %s server-host", myname);
if ((hp = gethostbyname (smtphost)) == NULL)
adios (NULL," %s: unknown host");
bzero ((char *) msock, sizeof *msock);
msock -> sin_family = hp -> h_addrtype;
bcopy (hp -> h_addr, (char *) &msock -> sin_addr, hp -> h_length);
}
/* */
static envinit () {
int i,
sd;
if (!(debug = isatty (2))) {
for (i = 0; i < 5; i++) {
switch (fork ()) {
case NOTOK:
sleep (5);
continue;
case OK:
break;
default:
_exit (0);
}
break;
}
(void) chdir ("/");
if ((sd = open ("/dev/null", O_RDWR)) == NOTOK)
adios ("/dev/null", "unable to read");
if (sd != 0)
(void) dup2 (sd, 0), (void) close (sd);
(void) dup2 (0, 1);
(void) dup2 (0, 2);
if ((sd = open ("/dev/tty", O_RDWR)) != NOTOK) {
(void) ioctl (sd, TIOCNOTTY, NULL);
(void) close (sd);
}
}
for (sd = 3; sd < nbits; sd++)
(void) close (sd);
(void) signal (SIGPIPE, SIG_IGN);
openlog (myname, LOG_PID);
advise (NULL, LOG_INFO, "starting");
}
/* */
/* ARGSUSED */
static void chldser (sig, code, sc)
int sig;
long code;
struct sigcontext *sc;
{
union wait status;
while (wait3 (&status, WNOHANG, NULL) > 0)
continue;
}
/* */
/* VARARGS */
void adios (what, fmt, a, b, c, d)
char *what,
*fmt,
*a,
*b,
*c,
*d;
{
advise (what, LOG_SALERT, fmt, a, b, c, d);
_exit (1);
}
/* VARARGS */
void advise (what, code, fmt, a, b, c, d)
char *what,
*fmt,
*a,
*b,
*c,
*d;
int code;
{
char buffer[BUFSIZ];
if (what) {
sprintf (buffer, fmt, a, b, c, d);
syslog (code, "%s %s: %m", buffer, what);
}
else
syslog (code, fmt, a, b, c, d);
if (debug) {
fprintf (stderr, "[%d] ", code);
fprintf (stderr, fmt, a, b, c, d);
if (what)
(void) fputc (' ', stderr), perror (what);
else
(void) fputc ('\n', stderr);
(void) fflush (stderr);
}
}