ipop3d.c

广泛使用的邮件服务器！同时

	}

	else if (!strcmp (s,"RETR")) {
	  if (t && *t) {	/* must have an argument */
	    if ((i = strtoul (t,NIL,10)) && (i <= nmsgs) && msg[i] &&
		!(flags[i] & DELE)) {
	      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);
				/* if not marked seen or noted to be marked */
	      if (!(elt->seen || (flags[i] & SEEN))) {
		++nseen;	/* note that we need to mark it seen */
		flags[i] |= SEEN;
	      }
				/* get header */
	      t = mail_fetch_header (stream,msg[i],NIL,NIL,&k,FT_PEEK);
	      blat (t,-1,k,NIL);/* write up to trailing CRLF */
				/* build status */
	      sprintf (tmp,STATUS,elt->seen ? "R" : " ",
		       elt->recent ? " " : "O");
	      if (k < 4) CRLF;	/* don't write Status: if no header */
				/* normal header ending with CRLF CRLF? */
	      else if (t[k-3] == '\012') {
		PSOUT (tmp);	/* write status */
		CRLF;		/* then write second CRLF */
	      }
	      else {		/* abnormal - no blank line at end of header */
		CRLF;		/* write CRLF first then */
		PSOUT (tmp);
	      }
				/* output text */
	      t = mail_fetch_text (stream,msg[i],NIL,&k,
				   FT_RETURNSTRINGSTRUCT | FT_PEEK);
	      if (k) {		/* only if there is a text body */
		blat (t,-1,k,&stream->private.string);
		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] &&
		!(flags[i] & DELE)) {
				/* update highest message accessed */
	      if (i > last) last = i;
	      flags[i] |= DELE;	/* note that deletion is requested */
	      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] &&
	      !(flags[i] & DELE)) {
				/* skip whitespace */
	    while (*s == ' ') s++;
				/* make sure line count argument good */
	    if ((*s >= '0') && (*s <= '9')) {
	      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");
				/* get header */
	      t = mail_fetch_header (stream,msg[i],NIL,NIL,&k,FT_PEEK);
	      blat (t,-1,k,NIL);/* write up to trailing CRLF */
				/* build status */
	      sprintf (tmp,STATUS,elt->seen ? "R" : " ",
		       elt->recent ? " " : "O");
	      if (k < 4) CRLF;	/* don't write Status: if no header */
				/* normal header ending with CRLF CRLF? */
	      else if (t[k-3] == '\012') {
		PSOUT (tmp);	/* write status */
		CRLF;		/* then write second CRLF */
	      }
	      else {		/* abnormal - no blank line at end of header */
		CRLF;		/* write CRLF first then */
		PSOUT (tmp);
	      }
	      if (j) {		/* want any text lines? */
				/* output text */
		t = mail_fetch_text (stream,msg[i],NIL,&k,
				     FT_PEEK | FT_RETURNSTRINGSTRUCT);
				/* tie off final line if full text output */
		if (k && (j -= blat (t,j,k,&stream->private.string))) 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)) {
	goodbye = "-ERR Autologout\015\012";
	logout = "Autologout";
	state = LOGOUT;		/* sayonara */
      }
    }
  }

				/* open and need to update? */
  if (stream && (state == UPDATE)) {
    if (nseen) {		/* only bother if messages need marking seen */
      *(s = tmp) = '\0';	/* clear sequence */
      for (i = 1; i <= nmsgs; ++i) if (flags[i] & SEEN) {
	for (j = i + 1, k = 0; (j <= nmsgs) && (flags[j] & SEEN); ++j) k = j;
	if (k) sprintf (s,",%lu:%lu",i,k);
	else sprintf (s,",%lu",i);
	s += strlen (s);		/* point to end of string */
	if ((s - tmp) > (MAILTMPLEN - 30)) {
	  mail_setflag (stream,tmp + 1,"\\Seen");
	  *(s = tmp) = '\0';	/* restart sequence */
	}
	i = j;			/* continue after the range */
      }
      if (tmp[0]) mail_setflag (stream,tmp + 1,"\\Seen");
    }
    if (ndele) {		/* any messages to delete? */
      *(s = tmp) = '\0';	/* clear sequence */
      for (i = 1; i <= nmsgs; ++i) if (flags[i] & DELE) {
	for (j = i + 1, k = 0; (j <= nmsgs) && (flags[j] & DELE); ++j) k = j;
	if (k) sprintf (s,",%lu:%lu",i,k);
	else sprintf (s,",%lu",i);
	s += strlen (s);	/* point to end of string */
	if ((s - tmp) > (MAILTMPLEN - 30)) {
	  mail_setflag (stream,tmp + 1,"\\Deleted");
	  *(s = tmp) = '\0';	/* restart sequence */
	}
	i = j;			/* continue after the range */
      }
      if (tmp[0]) mail_setflag (stream,tmp + 1,"\\Deleted");
      mail_expunge (stream);
    }
    syslog (LOG_INFO,"Update user=%.80s host=%.80s nmsgs=%lu ndele=%lu nseen=%lu",
	    user,tcp_clienthost (),stream->nmsgs,ndele,nseen);
    mail_close (stream);
  }
  sayonara (0);
  return 0;			/* stupid compilers */
}


/* Say goodbye
 * Accepts: exit status
 *
 * Does not return
 */

void sayonara (int status)
{
  logouthook_t lgoh = (logouthook_t) mail_parameters (NIL,GET_LOGOUTHOOK,NIL);
  if (goodbye) {		/* have a goodbye message? */
    PSOUT (goodbye);
    PFLUSH ();			/* make sure blatted */
  }
  syslog (LOG_INFO,"%s user=%.80s host=%.80s",logout,
	  user ? (char *) user : "???",tcp_clienthost ());
				/* do logout hook if needed */
  if (lgoh) (*lgoh) (mail_parameters (NIL,GET_LOGOUTDATA,NIL));
  _exit (status);		/* all done */
}

/* Clock interrupt
 */

void clkint ()
{
  alarm (0);			/* disable all interrupts */
  server_init (NIL,NIL,NIL,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN);
  goodbye = "-ERR Autologout; idle for too long\015\012";
  logout = "Autologout";
  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);
    }
    state = LOGOUT;
    stream = NIL;
    sayonara (1);
  }
}


/* Kiss Of Death interrupt
 */

void kodint ()
{
				/* only if idle */
  if (idletime && ((time (0) - idletime) > KODTIMEOUT)) {
    alarm (0);			/* disable all interrupts */
    server_init (NIL,NIL,NIL,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN);
    goodbye = "-ERR Received Kiss of Death\015\012";
    logout = "Killed (lost mailbox lock)";
    if (critical) state =LOGOUT;/* must defer if in critical code */
    else {			/* try to gracefully close the stream */
      if ((state == TRANSACTION) && !stream->lock) {
	rset ();
	mail_close (stream);
      }
      state = LOGOUT;
      stream = NIL;
      sayonara (1);		/* die die die */
    }
  }
}


/* Hangup interrupt
 */

void hupint ()
{
  alarm (0);			/* disable all interrupts */
  server_init (NIL,NIL,NIL,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN);
  goodbye = NIL;		/* nobody left to talk to */
  logout = "Hangup";
  if (critical) state = LOGOUT;	/* must defer if in critical code */
  else {			/* try to gracefully close the stream */
    if ((state == TRANSACTION) && !stream->lock) {
      rset ();
      mail_close (stream);
    }
    state = LOGOUT;
    stream = NIL;
    sayonara (1);		/* die die die */
  }
}


/* Termination interrupt
 */

void trmint ()
{
  alarm (0);			/* disable all interrupts */
  server_init (NIL,NIL,NIL,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN,SIG_IGN);
  goodbye = "-ERR Killed\015\012";
  logout = "Killed";
  if (critical) state = LOGOUT;	/* must defer if in critical code */
  /* Make no attempt at graceful closure since a shutdown may be in
   * progress, and we won't have any time to do mail_close() actions.
   */
  else sayonara (1);		/* die die die */
}

/* Parse PASS command
 * Accepts: pointer to command argument
 * Returns: new state
 */

int pass_login (char *t,int argc,char *argv[])
{
  char tmp[MAILTMPLEN];
				/* flush old passowrd */
  if (pass) fs_give ((void **) &pass);
  if (!(t && *t)) {		/* if no password given */
    PSOUT ("-ERR Missing password argument\015\012");
    return AUTHORIZATION;
  }
  pass = cpystr (t);		/* copy password argument */
  if (!host) {			/* want remote mailbox? */
				/* no, delimit user from possible admin */
    if (t = strchr (user,'*')) *t++ ='\0';
				/* attempt the login */
    if (server_login (user,pass,t,argc,argv)) {
      int ret = mbxopen ("INBOX");
      if (ret == TRANSACTION)	/* mailbox opened OK? */
	syslog (LOG_INFO,"%sLogin user=%.80s host=%.80s nmsgs=%lu/%lu",
		t ? "Admin " : "",user,tcp_clienthost (),nmsgs,stream->nmsgs);
      else syslog (LOG_INFO,"%sLogin user=%.80s host=%.80s no mailbox",
		   t ? "Admin " : "",user,tcp_clienthost ());
      return ret;
    }
  }
#ifndef DISABLE_POP_PROXY
				/* remote; build remote INBOX */
  else if (anonymous_login (argc,argv)) {
    syslog (LOG_INFO,"IMAP login to host=%.80s user=%.80s host=%.80s",host,
	    user,tcp_clienthost ());
    sprintf (tmp,"{%.128s/user=%.128s}INBOX",host,user);
				/* disable rimap just in case */
    mail_parameters (NIL,SET_RSHTIMEOUT,0);
    return mbxopen (tmp);
  }
#endif
				/* vague error message to confuse crackers */
  PSOUT ("-ERR Bad login\015\012");
  return AUTHORIZATION;
}

/* Authentication responder
 * Accepts: challenge
 *	    length of challenge
 *	    pointer to response length return location if non-NIL
 * Returns: response
 */

#define RESPBUFLEN 8*MAILTMPLEN

char *responder (void *challenge,unsigned long clen,unsigned long *rlen)
{
  unsigned long i,j;
  unsigned char *t,resp[RESPBUFLEN];
  char tmp[MAILTMPLEN];
  if (initial) {		/* initial response given? */
    if (clen) return NIL;	/* not permitted */
				/* set up response */
    t = (unsigned char *) initial;
    initial = NIL;		/* no more initial response */
    return (char *) rfc822_base64 (t,strlen ((char *) t),rlen ? rlen : &i);
  }
  PSOUT ("+ ");
  for (t = rfc822_binary (challenge,clen,&i),j = 0; j < i; j++)
    if (t[j] > ' ') PBOUT (t[j]);
  fs_give ((void **) &t);
  CRLF;
  PFLUSH ();			/* dump output buffer */
  resp[RESPBUFLEN-1] = '\0';	/* last buffer character is guaranteed NUL */
  alarm (LOGINTIMEOUT);		/* get a response under timeout */
  clearerr (stdin);		/* clear stdin errors */
				/* read buffer */