ipop3d.c

广泛使用的邮件服务器！同时

/* ========================================================================
 * Copyright 1988-2008 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
 */

/*
 * Program:	IPOP3D - IMAP to POP3 conversion server
 *
 * Author:	Mark Crispin
 *		UW Technology
 *		University of Washington
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	1 November 1990
 * Last Edited:	19 February 2008
 */

/* Parameter files */

#include <stdio.h>
#include <ctype.h>
#include <errno.h>
extern int errno;		/* just in case */
#include <signal.h>
#include <time.h>
#include "c-client.h"


#define CRLF PSOUT ("\015\012")	/* primary output terpri */


/* Autologout timer */
#define KODTIMEOUT 60*5
#define LOGINTIMEOUT 60*3
#define TIMEOUT 60*10


/* Server states */

#define AUTHORIZATION 0
#define TRANSACTION 1
#define UPDATE 2
#define LOGOUT 3

/* Eudora food */

#define STATUS "Status: %s%s\015\012"
#define SLEN (sizeof (STATUS)-3)


/* Global storage */

char *version = "104";		/* edit number of this server */
short state = AUTHORIZATION;	/* server state */
short critical = NIL;		/* non-zero if in critical code */
MAILSTREAM *stream = NIL;	/* mailbox stream */
time_t idletime = 0;		/* time we went idle */
unsigned long nmsgs = 0;	/* current number of messages */
unsigned long ndele = 0;	/* number of deletes */
unsigned long nseen = 0;	/* number of mark-seens */
unsigned long last = 0;		/* highest message accessed */
unsigned long il = 0;		/* initial last message */
char challenge[128];		/* challenge */
char *host = NIL;		/* remote host name */
char *user = NIL;		/* user name */
char *pass = NIL;		/* password */
char *initial = NIL;		/* initial response */
long *msg = NIL;		/* message translation vector */
short *flags = NIL;		/* flags */
char *logout = "Logout";
char *goodbye = "+OK Sayonara\015\012";


/* POP3 flags */

#define DELE 0x1
#define SEEN 0x2


/* Function prototypes */

int main (int argc,char *argv[]);
void sayonara (int status);
void clkint ();
void kodint ();
void hupint ();
void trmint ();
int pass_login (char *t,int argc,char *argv[]);
char *apop_login (char *chal,char *user,char *md5,int argc,char *argv[]);
char *responder (void *challenge,unsigned long clen,unsigned long *rlen);
int mbxopen (char *mailbox);
long blat (char *text,long lines,unsigned long size,STRING *st);
void rset ();

/* Main program */

int main (int argc,char *argv[])
{
  unsigned long i,j,k;
  char *s,*t;
  char tmp[MAILTMPLEN];
  time_t autologouttime;
  char *pgmname = (argc && argv[0]) ?
    (((s = strrchr (argv[0],'/')) || (s = strrchr (argv[0],'\\'))) ?
     s+1 : argv[0]) : "ipop3d";
				/* set service name before linkage */
  mail_parameters (NIL,SET_SERVICENAME,(void *) "pop");
#include "linkage.c"
				/* initialize server */
  server_init (pgmname,"pop3","pop3s",clkint,kodint,hupint,trmint,NIL);
  mail_parameters (NIL,SET_BLOCKENVINIT,VOIDT);
  s = myusername_full (&i);	/* get user name and flags */
  mail_parameters (NIL,SET_BLOCKENVINIT,NIL);
  if (i == MU_LOGGEDIN) {	/* allow EXTERNAL if logged in already */
    mail_parameters (NIL,UNHIDE_AUTHENTICATOR,(void *) "EXTERNAL");
    mail_parameters (NIL,SET_EXTERNALAUTHID,(void *) s);
  }
  {				/* set up MD5 challenge */
    AUTHENTICATOR *auth = mail_lookup_auth (1);
    while (auth && compare_cstring (auth->name,"CRAM-MD5")) auth = auth->next;
				/* build challenge -- less than 128 chars */
    if (auth && auth->server && !(auth->flags & AU_DISABLE))
      sprintf (challenge,"<%lx.%lx@%.64s>",(unsigned long) getpid (),
	       (unsigned long) time (0),tcp_serverhost ());
    else challenge[0] = '\0';	/* no MD5 authentication */
  }
  /* There are reports of POP3 clients which get upset if anything appears
   * between the "+OK" and the "POP3" in the greeting.
   */
  PSOUT ("+OK POP3 ");
  if (!challenge[0]) {		/* if no MD5 enable, output host name */
    PSOUT (tcp_serverhost ());
    PBOUT (' ');
  }
  PSOUT (CCLIENTVERSION);
  PBOUT ('.');
  PSOUT (version);
  PSOUT (" server ready");
  if (challenge[0]) {		/* if MD5 enable, output challenge here */
    PBOUT (' ');
    PSOUT (challenge);
  }
  CRLF;
  PFLUSH ();			/* dump output buffer */
  autologouttime = time (0) + LOGINTIMEOUT;
				/* command processing loop */
  while ((state != UPDATE) && (state != LOGOUT)) {
    idletime = time (0);	/* get a command under timeout */
    alarm ((state == TRANSACTION) ? TIMEOUT : LOGINTIMEOUT);
    clearerr (stdin);		/* clear stdin errors */
				/* read command line */
    while (!PSIN (tmp,MAILTMPLEN)) {
				/* ignore if some interrupt */
      if (ferror (stdin) && (errno == EINTR)) clearerr (stdin);
      else {
	char *e = ferror (stdin) ?
	  strerror (errno) : "Unexpected client disconnect";
	alarm (0);		/* disable all interrupts */
	server_init (NIL,NIL,NIL,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN);
	sprintf (logout = tmp,"%.80s, while reading line",e);
	goodbye = NIL;
	rset ();		/* try to gracefully close the stream */
	if (state == TRANSACTION) mail_close (stream);
	stream = NIL;
	state = LOGOUT;
	sayonara (1);
      }
    }
    alarm (0);			/* make sure timeout disabled */
    idletime = 0;		/* no longer idle */

    if (!strchr (tmp,'\012'))	/* find end of line */
      PSOUT ("-ERR Command line too long\015\012");
    else if (!(s = strtok (tmp," \015\012")))
      PSOUT ("-ERR Null command\015\012");
    else {			/* dispatch based on command */
      ucase (s);		/* canonicalize case */
				/* snarf argument */
      t = strtok (NIL,"\015\012");
				/* QUIT command always valid */
      if (!strcmp (s,"QUIT")) state = UPDATE;
      else if (!strcmp (s,"CAPA")) {
	AUTHENTICATOR *auth;
	PSOUT ("+OK Capability list follows:\015\012");
	PSOUT ("TOP\015\012LOGIN-DELAY 180\015\012UIDL\015\012");
	if (s = ssl_start_tls (NIL)) fs_give ((void **) &s);
	else PSOUT ("STLS\015\012");
	if (i = !mail_parameters (NIL,GET_DISABLEPLAINTEXT,NIL))
	  PSOUT ("USER\015\012");
				/* display secure server authenticators */
	for (auth = mail_lookup_auth (1), s = "SASL"; auth; auth = auth->next)
	  if (auth->server && !(auth->flags & AU_DISABLE) &&
	      !(auth->flags & AU_HIDE) && (i || (auth->flags & AU_SECURE))) {
	    if (s) {
	      PSOUT (s);
	      s = NIL;
	    }
	    PBOUT (' ');
	    PSOUT (auth->name);
	  }
	PSOUT (s ? ".\015\012" : "\015\012.\015\012");
      }

      else switch (state) {	/* else dispatch based on state */
      case AUTHORIZATION:	/* waiting to get logged in */
	if (!strcmp (s,"AUTH")) {
	  if (t && *t) {	/* mechanism given? */
	    if (host) fs_give ((void **) &host);
	    if (user) fs_give ((void **) &user);
	    if (pass) fs_give ((void **) &pass);
	    s = strtok (t," ");	/* get mechanism name */
				/* get initial response */
	    if (initial = strtok (NIL,"\015\012")) {
	      if ((*initial == '=') && !initial[1]) ++initial;
	      else if (!*initial) initial = NIL;
	    }
	    if (!(user = cpystr (mail_auth (s,responder,argc,argv)))) {
	      PSOUT ("-ERR Bad authentication\015\012");
	      syslog (LOG_INFO,"AUTHENTICATE %s failure host=%.80s",s,
		      tcp_clienthost ());
	    }
	    else if ((state = mbxopen ("INBOX")) == TRANSACTION)
	      syslog (LOG_INFO,"Auth user=%.80s host=%.80s nmsgs=%lu/%lu",
		      user,tcp_clienthost (),nmsgs,stream->nmsgs);
	    else syslog (LOG_INFO,"Auth user=%.80s host=%.80s no mailbox",
			 user,tcp_clienthost ());
	  }
	  else {
	    AUTHENTICATOR *auth;
	    PSOUT ("+OK Supported authentication mechanisms:\015\012");
	    i = !mail_parameters (NIL,GET_DISABLEPLAINTEXT,NIL);
	    for (auth = mail_lookup_auth (1); auth; auth = auth->next)
	      if (auth->server && !(auth->flags & AU_DISABLE) &&
		  !(auth->flags & AU_HIDE) &&
		  (i || (auth->flags & AU_SECURE))) {
		PSOUT (auth->name);
		CRLF;
	      }
	    PBOUT ('.');
	    CRLF;
	  }
	}

	else if (!strcmp (s,"APOP")) {
	  if (challenge[0]) {	/* can do it if have an MD5 challenge */
	    if (host) fs_give ((void **) &host);
	    if (user) fs_give ((void **) &user);
	    if (pass) fs_give ((void **) &pass);
				/* get user name */
	    if (!(t && *t && (s = strtok (t," ")) && (t = strtok(NIL,"\012"))))
	      PSOUT ("-ERR Missing APOP argument\015\012");
	    else if (!(user = apop_login (challenge,s,t,argc,argv)))
	      PSOUT ("-ERR Bad APOP\015\012");
	    else if ((state = mbxopen ("INBOX")) == TRANSACTION)
	      syslog (LOG_INFO,"APOP user=%.80s host=%.80s nmsgs=%lu/%lu",
		      user,tcp_clienthost (),nmsgs,stream->nmsgs);
	    else syslog (LOG_INFO,"APOP user=%.80s host=%.80s no mailbox",
			 user,tcp_clienthost ());
	  }
	  else PSOUT ("-ERR Not supported\015\012");
	}
				/* (chuckle) */
	else if (!strcmp (s,"RPOP"))
	  PSOUT ("-ERR Nice try, bunkie\015\012");
	else if (!strcmp (s,"STLS")) {
	  if (t = ssl_start_tls (pgmname)) {
	    PSOUT ("-ERR STLS failed: ");
	    PSOUT (t);
	    CRLF;
	  }
	  else PSOUT ("+OK STLS completed\015\012");
	}
	else if (!mail_parameters (NIL,GET_DISABLEPLAINTEXT,NIL) &&
		 !strcmp (s,"USER")) {
	  if (host) fs_give ((void **) &host);
	  if (user) fs_give ((void **) &user);
	  if (pass) fs_give ((void **) &pass);
	  if (t && *t) {	/* if user name given */
				/* skip leading whitespace (bogus clients!) */
	    while (*t == ' ') ++t;
				/* remote user name? */
	    if (s = strchr (t,':')) {
	      *s++ = '\0';	/* tie off host name */
	      host = cpystr (t);/* copy host name */
	      user = cpystr (s);/* copy user name */
	    }
				/* local user name */
	    else user = cpystr (t);
	    PSOUT ("+OK User name accepted, password please\015\012");
	  }
	  else PSOUT ("-ERR Missing username argument\015\012");
	}
	else if (!mail_parameters (NIL,GET_DISABLEPLAINTEXT,NIL) &&
		 user && *user && !strcmp (s,"PASS"))
	  state = pass_login (t,argc,argv);
	else PSOUT ("-ERR Unknown AUTHORIZATION state command\015\012");
	break;

      case TRANSACTION:		/* logged in */
	if (!strcmp (s,"STAT")) {
	  for (i = 1,j = 0,k = 0; i <= nmsgs; i++)
				/* message still exists? */
	    if (msg[i] && !(flags[i] & DELE)) {
	      j++;		/* count one more undeleted message */
	      k += mail_elt (stream,msg[i])->rfc822_size + SLEN;
	    }
	  sprintf (tmp,"+OK %lu %lu\015\012",j,k);
	  PSOUT (tmp);
	}
	else if (!strcmp (s,"LIST")) {
	  if (t && *t) {	/* argument do single message */
	    if ((i = strtoul (t,NIL,10)) && (i <= nmsgs) && msg[i] &&
		!(flags[i] & DELE)) {
	      sprintf (tmp,"+OK %lu %lu\015\012",i,
		       mail_elt(stream,msg[i])->rfc822_size + SLEN);
	      PSOUT (tmp);
	    }
	    else PSOUT ("-ERR No such message\015\012");
	  }
	  else {		/* entire mailbox */
	    PSOUT ("+OK Mailbox scan listing follows\015\012");
	    for (i = 1,j = 0,k = 0; i <= nmsgs; i++)
	      if (msg[i] && !(flags[i] & DELE)) {
		sprintf (tmp,"%lu %lu\015\012",i,
			 mail_elt (stream,msg[i])->rfc822_size + SLEN);
		PSOUT (tmp);
	      }
	    PBOUT ('.');	/* end of list */
	    CRLF;
	  }
	}
	else if (!strcmp (s,"UIDL")) {
	  if (t && *t) {	/* argument do single message */
	    if ((i = strtoul (t,NIL,10)) && (i <= nmsgs) && msg[i] &&
		!(flags[i] & DELE)) {
	      sprintf (tmp,"+OK %lu %08lx%08lx\015\012",i,stream->uid_validity,
		       mail_uid (stream,msg[i]));
	      PSOUT (tmp);
	    }
	    else PSOUT ("-ERR No such message\015\012");
	  }
	  else {		/* entire mailbox */
	    PSOUT ("+OK Unique-ID listing follows\015\012");
	    for (i = 1,j = 0,k = 0; i <= nmsgs; i++)
	      if (msg[i] && !(flags[i] & DELE)) {
		sprintf (tmp,"%lu %08lx%08lx\015\012",i,stream->uid_validity,
			 mail_uid (stream,msg[i]));
		PSOUT (tmp);
	      }
	    PBOUT ('.');	/* end of list */
	    CRLF;
	  }