ipop3d.c

Vovida 社区开源的 SIP 协议源码

/*
 * Program:	IPOP3D - IMAP to POP3 conversion server
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	1 November 1990
 * Last Edited:	3 August 2000
 *
 * Copyright 2000 by the University of Washington
 *
 *  Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appears in all copies and that both the
 * above copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the University of Washington not be
 * used in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  This software is made
 * available "as is", and
 * THE UNIVERSITY OF WASHINGTON DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
 * WITH REGARD TO THIS SOFTWARE, INCLUDING WITHOUT LIMITATION ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, AND IN
 * NO EVENT SHALL THE UNIVERSITY OF WASHINGTON BE LIABLE FOR ANY SPECIAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, TORT
 * (INCLUDING NEGLIGENCE) OR STRICT LIABILITY, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#define PBIN getchar
#define PSIN(s,n) fgets (s,n,stdin)
#define PBOUT(c) putchar (c)
#define PSOUT(s) fputs (s,stdout)
#define PFLUSH fflush (stdout)
#define CRLF PSOUT ("\015\012")

/* 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"


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


/* Size of temporary buffers */
#define TMPLEN 1024


/* 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 = "2000.68";	/* server version */
short state = AUTHORIZATION;	/* server state */
short critical = NIL;		/* non-zero if in critical code */
MAILSTREAM *stream = NIL;	/* mailbox stream */
long idletime = 0;		/* time we went idle */
unsigned long nmsgs = 0;	/* current number of messages */
unsigned long ndele = 0;	/* number of deletes */
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 */
char *sayonara = "+OK Sayonara\015\012";


/* Function prototypes */

int main (int argc,char *argv[]);
void clkint ();
void kodint ();
void hupint ();
void trmint ();
int 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);
void rset ();

/* Main program */

int main (int argc,char *argv[])
{
  unsigned long i,j,k;
  char *s,*t;
  char tmp[TMPLEN];
  time_t autologouttime;
#include "linkage.c"
				/* initialize server */
  server_init (argv[0],"pop3","pop3s","pop",clkint,kodint,hupint,trmint);
  challenge[0] = '\0';		/* find the CRAM-MD5 authenticator */
  if (i = mail_lookup_auth_name ("CRAM-MD5",NIL)) {
    AUTHENTICATOR *a = mail_lookup_auth (i);
    if (a->server) {		/* have an MD5 enable file? */
				/* build challenge -- less than 128 chars */
      sprintf (challenge,"<%lx.%lx@%.64s>",(unsigned long) getpid (),
	       (unsigned long) time (0),tcp_serverhost ());
    }
  }
  /* 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 */
    PBOUT (' ');
    PSOUT (tcp_serverhost ());
  }
  PSOUT (" v");
  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 */
    while (!PSIN (tmp,TMPLEN)){	/* read command line */
				/* ignore if some interrupt */
      if (ferror (stdin) && (errno == EINTR)) clearerr (stdin);
      else {
	char *e = ferror (stdin) ?
	  strerror (errno) : "Command stream end of file";
	alarm (0);		/* disable all interrupts */
	syslog (LOG_INFO,"%s while reading line user=%.80s host=%.80s",
		e,user ? user : "???",tcp_clienthost ());
	rset ();		/* try to gracefully close the stream */
	if (state == TRANSACTION) mail_close (stream);
	stream = NIL;
	state = LOGOUT;
	_exit (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 = mail_lookup_auth (1);
	PSOUT ("+OK Capability list follows:\015\012");
	PSOUT ("TOP\015\012LOGIN-DELAY 180\015\012UIDL\015\012");
#ifdef POP3SPECIALCAP
	PSOUT (POP3SPECIALCAP);
	CRLF;
#endif
#ifndef PLAINTEXT_DISABLED
	PSOUT ("USER\015\012");
#endif
	PSOUT ("SASL");
	while (auth) {
#ifdef PLAINTEXT_DISABLED
				/* disable insecure authenticators */
	  if (!auth->secflag) auth->server = NIL;
#endif
	  if (auth->server) {
	    PBOUT (' ');
	    PSOUT (auth->name);
	  }
	  auth = auth->next;
	}
	CRLF;
	PSOUT (".\015\012");
      }

      else switch (state) {	/* else dispatch based on state */
      case AUTHORIZATION:	/* waiting to get logged in */
	if (!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 (user && *user && !strcmp (s,"PASS"))
	  state = login (t,argc,argv);
	else 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 */
	    initial = strtok (NIL,"\015\012");
	    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=%ld/%ld",
		      user,tcp_clienthost (),nmsgs,stream->nmsgs);
	    else syslog (LOG_INFO,"Auth user=%.80s host=%.80s no mailbox",
			 user,tcp_clienthost ());
	  }
	  else {
	    AUTHENTICATOR *auth = mail_lookup_auth (1);
	    PSOUT ("+OK Supported authentication mechanisms:\015\012");
	    while (auth) {
#ifdef PLAINTEXT_DISABLED
				/* disable insecure authenticators */
	      if (!auth_secflag) auth->server = NIL;
#endif
	      if (auth->server) {
		PSOUT (auth->name);
		CRLF;
	      }
	      auth = auth->next;
	    }
	    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=%ld/%ld",
		      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");
#ifdef IMAPSPECIALCAP
	else if (!strcmp (s,POP3SPECIALCAP)) {
	  char rsp[TMPLEN];
	  if (t = SPECIALCAP (argv[0]))
	    sprintf (rsp,"-ERR %s failed: %.100s\015\012",POP3SPECIALCAP,t);
	  else sprintf (rsp,"+OK %s completed\015\012",POP3SPECIALCAP);
	  PSOUT (rsp);
	}
#endif
	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++)
	    if (msg[i] > 0) {	/* message still exists? */
	      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] > 0)) {
	      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] > 0) {
	      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] > 0)) {
	      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] > 0) {
	      sprintf (tmp,"%lu %08lx%08lx\015\012",i,stream->uid_validity,
		       mail_uid (stream,msg[i]));
	      PSOUT (tmp);
	    }
	    PBOUT ('.');	/* end of list */
	    CRLF;
	  }
	}

	else if (!strcmp (s,"RETR")) {
	  if (t && *t) {	/* must have an argument */
	    if ((i = strtoul (t,NIL,10)) && (i <= nmsgs) && (msg[i] > 0)) {
	      MESSAGECACHE *elt;
				/* update highest message accessed */
	      if (i > last) last = i;
	      sprintf (tmp,"+OK %lu octets\015\012",
		       (elt = mail_elt (stream,msg[i]))->rfc822_size + SLEN);
	      PSOUT (tmp);
				/* output header */
	      t = mail_fetch_header (stream,msg[i],NIL,NIL,&k,FT_PEEK);
	      blat (t,-1,k);
				/* output status */
	      sprintf (tmp,STATUS,elt->seen ? "R" : " ",
		       elt->recent ? " " : "O");
	      PSOUT (tmp);
	      CRLF;		/* delimit header and text */
				/* output text */
	      t = mail_fetch_text (stream,msg[i],NIL,&k,NIL);
	      blat (t,-1,k);
	      CRLF;		/* end of list */
	      PBOUT ('.');
	      CRLF;
	    }
	    else PSOUT ("-ERR No such message\015\012");
	  }
	  else PSOUT ("-ERR Missing message number argument\015\012");
	}
	else if (!strcmp (s,"DELE")) {
	  if (t && *t) {	/* must have an argument */
	    if ((i = strtoul (t,NIL,10)) && (i <= nmsgs) && (msg[i] > 0)) {
				/* update highest message accessed */
	      if (i > last) last = i;
				/* delete message */
	      sprintf (tmp,"%ld",msg[i]);
	      mail_setflag (stream,tmp,"\\Deleted");
	      msg[i] = -msg[i];	/* note that we deleted this message */
	      PSOUT ("+OK Message deleted\015\012");
	      ndele++;		/* one more message deleted */
	    }
	    else PSOUT ("-ERR No such message\015\012");
	  }
	  else PSOUT ("-ERR Missing message number argument\015\012");
	}

	else if (!strcmp (s,"NOOP"))
	  PSOUT ("+OK No-op to you too!\015\012");
	else if (!strcmp (s,"LAST")) {
	  sprintf (tmp,"+OK %lu\015\012",last);
	  PSOUT (tmp);
	}
	else if (!strcmp (s,"RSET")) {
	  rset ();		/* reset the mailbox */
	  PSOUT ("+OK Reset state\015\012");
	}
	else if (!strcmp (s,"TOP")) {
	  if (t && *t && (i =strtoul (t,&s,10)) && (i <= nmsgs) &&
	      (msg[i] > 0)) {
				/* skip whitespace */
	    while (isspace (*s)) s++;
	    if (isdigit (*s)) {	/* make sure line count argument good */
	      MESSAGECACHE *elt = mail_elt (stream,msg[i]);
	      j = strtoul (s,NIL,10);
				/* update highest message accessed */
	      if (i > last) last = i;
	      PSOUT ("+OK Top of message follows\015\012");
				/* output header */
	      t = mail_fetch_header (stream,msg[i],NIL,NIL,&k,FT_PEEK);
	      blat (t,-1,k);
				/* output status */
	      sprintf (tmp,STATUS,elt->seen ? "R" : " ",
		       elt->recent ? " " : "O");
	      PSOUT (tmp);
	      CRLF;		/* delimit header and text */
	      if (j) {		/* want any text lines? */
				/* output text */
		t = mail_fetch_text (stream,msg[i],NIL,&k,FT_PEEK);
				/* tie off final line if full text output */
		if (j -= blat (t,j,k)) CRLF;
	      }
	      PBOUT ('.');	/* end of list */
	      CRLF;
	    }
	    else PSOUT ("-ERR Bad line count argument\015\012");
	  }
	  else PSOUT ("-ERR Bad message number argument\015\012");
	}
	else if (!strcmp (s,"XTND"))
	  PSOUT ("-ERR Sorry I can't do that\015\012");
	else PSOUT ("-ERR Unknown TRANSACTION state command\015\012");
	break;
      default:
        PSOUT ("-ERR Server in unknown state\015\012");
	break;
      }
    }
    PFLUSH;			/* make sure output finished */
    if (autologouttime) {	/* have an autologout in effect? */
				/* cancel if no longer waiting for login */
      if (state != AUTHORIZATION) autologouttime = 0;
				/* took too long to login */
      else if (autologouttime < time (0)) {
	PSOUT ("-ERR Autologout\015\012");
	syslog (LOG_INFO,"Autologout host=%.80s",tcp_clienthost ());
	PFLUSH;			/* make sure output blatted */
	state = LOGOUT;		/* sayonara */
      }
    }
  }
  if (stream && (state == UPDATE)) {
    mail_expunge (stream);
    syslog (LOG_INFO,"Logout user=%.80s host=%.80s nmsgs=%ld ndele=%ld",
	    user,tcp_clienthost (),stream->nmsgs,ndele);
    mail_close (stream);
  }
  else syslog (LOG_INFO,"Logout user=%.80s host=%.80s",user ? user : "???",
	       tcp_clienthost ());
  PSOUT (sayonara);		/* "now it's time to say sayonara..." */
  PFLUSH;			/* make sure output finished */
  return 0;			/* all done */
}

/* Clock interrupt
 */

void clkint ()
{
  PSOUT ("-ERR Autologout; idle for too long\015\012");
  syslog (LOG_INFO,"Autologout user=%.80s host=%.80s",user ? user : "???",
	  tcp_clienthost ());
  PFLUSH;			/* make sure output blatted */
  if (critical) state = LOGOUT;	/* badly hosed if in critical code */
  else {			/* try to gracefully close the stream */
    if ((state == TRANSACTION) && !stream->lock) {
      rset ();
      mail_close (stream);