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<
# fetchmail control file sample (remove this header comment from yours!)
#
# This file (or one of your own creation, rather) should be located 
# in your home directory with the name .fetchmailrc.  Permissions on this
# file may be no greater than -rw------- (0600), or fetchmail will refuse to
# use it.
#
# To see what effect your ~/.fetchmailrc file has, do 
#
#	fetchmail --version
#
# This will display the fetchmail version number and an explanation
# in English of what the currently set options and defaults mean.
#
# Comments begin with a '#' and extend through the end of the line.
# Blank lines between server entries are ignored.
# Keywords and identifiers are case sensitive.
# When there is a conflict between the command-line arguments and the
# arguments in this file, the command-line arguments take precedence.
#
# The run control file format is fully described (with more examples) on the
# fetchmail manual page.
#
# This is what the former developer's .fetchmailrc looks like:

set daemon 300	# Sleep 300 seconds after the poll, then poll again.

defaults
	# only poll when the sl0 interface is up (only available on some systems)
	interface "sl0/10.0.2.15"	# SLIRP standard address
	# log in with name "esr" and do multidrop fetch for the users
	# esr, fetchmail-friends, and magic-numbers
	user esr is esr fetchmail-friends magic-numbers here
	# fetch (and delete after retrieval) all messages
	fetchall

# Use this for production
poll imap.example.org protocol IMAP:
	# do not use MX lookups to check of server aliases, but pass
	# them explicitly:
	no dns, aka snark.thyrsus.com thyrsus.com locke.example.org example.org 
	password my_remote_password;

# Use this to test POP3
skip pop3.example.org with protocol APOP:
	# do not use MX lookups to check of server aliases, but pass
	# them explicitly:
	no dns, aka snark.thyrsus.com thyrsus.com locke.example.org example.org 
	password my_apop_secret;

# Use this to test against a different server - it is skipped unless
# you give its name on fetchmail's command line.
skip pop3.netaxs.com:
	password my_netaxs.password;
89' href='#n289'>289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985
/*
 * imap.c -- IMAP2bis/IMAP4 protocol methods
 *
 * Copyright 1997 by Eric S. Raymond
 * For license terms, see the file COPYING in this directory.
 */

#include  "config.h"
#include  <stdio.h>
#include  <string.h>
#include  <ctype.h>
#if defined(STDC_HEADERS)
#include  <stdlib.h>
#include  <limits.h>
#endif
#include  "fetchmail.h"
#include  "socket.h"

#include  "i18n.h"

#if OPIE_ENABLE
#endif /* OPIE_ENABLE */

#ifndef strstr		/* glibc-2.1 declares this as a macro */
extern char *strstr();	/* needed on sysV68 R3V7.1. */
#endif /* strstr */

/* imap_version values */
#define IMAP2		-1	/* IMAP2 or IMAP2BIS, RFC1176 */
#define IMAP4		0	/* IMAP4 rev 0, RFC1730 */
#define IMAP4rev1	1	/* IMAP4 rev 1, RFC2060 */

static int count = 0, recentcount = 0, unseen = 0, deletions = 0;
static int expunged, expunge_period, saved_timeout = 0;
static int imap_version, preauth;
static flag do_idle;
static char capabilities[MSGBUFSIZE+1];
static unsigned int *unseen_messages;

static int imap_ok(int sock, char *argbuf)
/* parse command response */
{
    char buf[MSGBUFSIZE+1];

    do {
	int	ok;
	char	*cp;

	if ((ok = gen_recv(sock, buf, sizeof(buf))))
	    return(ok);

	/* all tokens in responses are caseblind */
	for (cp = buf; *cp; cp++)
	    if (islower(*cp))
		*cp = toupper(*cp);

	/* interpret untagged status responses */
	if (strstr(buf, "* CAPABILITY"))
	    strncpy(capabilities, buf + 12, sizeof(capabilities));
	else if (strstr(buf, "EXISTS"))
	{
	    count = atoi(buf+2);
	    /*
	     * Don't trust the message count passed by the server.
	     * Without this check, it might be possible to do a
	     * DNS-spoofing attack that would pass back a ridiculous 
	     * count, and allocate a malloc area that would overlap
	     * a portion of the stack.
	     */
	    if (count > INT_MAX/sizeof(int))
	    {
		report(stderr, "bogus message count!");
		return(PS_PROTOCOL);
	    }

	    /*
	     * Nasty kluge to handle RFC2177 IDLE.  If we know we're idling
	     * we can't wait for the tag matching the IDLE; we have to tell the
	     * server the IDLE is finished by shipping back a DONE when we
	     * see an EXISTS.  Only after that will a tagged response be
	     * shipped.  The idling flag also gets cleared on a timeout.
	     */
	    if (stage == STAGE_IDLE)
	    {
		/* we do our own write and report here to disable tagging */
		SockWrite(sock, "DONE\r\n", 6);
		if (outlevel >= O_MONITOR)
		    report(stdout, "IMAP> DONE\n");

		mytimeout = saved_timeout;
		stage = STAGE_FETCH;
	    }
	}
	else if (strstr(buf, "RECENT"))
	{
	    recentcount = atoi(buf+2);
	}
	else if (strstr(buf, "PREAUTH"))
	    preauth = TRUE;
	/*
	 * The server may decide to make the mailbox read-only, 
	 * which causes fetchmail to go into a endless loop
	 * fetching the same message over and over again. 
	 * 
	 * However, for check_only, we use EXAMINE which will
	 * mark the mailbox read-only as per the RFC.
	 * 
	 * This checks for the condition and aborts if 
	 * the mailbox is read-only. 
	 *
	 * See RFC 2060 section 6.3.1 (SELECT).
	 * See RFC 2060 section 6.3.2 (EXAMINE).
	 */ 
	else if (!check_only && strstr(buf, "[READ-ONLY]"))
	    return(PS_LOCKBUSY);
    } while
	(tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));

    if (tag[0] == '\0')
    {
	if (argbuf)
	    strcpy(argbuf, buf);
	return(PS_SUCCESS); 
    }
    else
    {
	char	*cp;

	/* skip the tag */
	for (cp = buf; !isspace(*cp); cp++)
	    continue;
	while (isspace(*cp))
	    cp++;

        if (strncmp(cp, "OK", 2) == 0)
	{
	    if (argbuf)
		strcpy(argbuf, cp);
	    return(PS_SUCCESS);
	}
	else if (strncmp(cp, "BAD", 3) == 0)
	    return(PS_ERROR);
	else if (strncmp(cp, "NO", 2) == 0)
	{
	    if (stage == STAGE_GETAUTH) 
		return(PS_AUTHFAIL);	/* RFC2060, 6.2.2 */
	    else
		return(PS_ERROR);
	}
	else
	    return(PS_PROTOCOL);
    }
}

#if NTLM_ENABLE
#include "ntlm.h"

static tSmbNtlmAuthRequest   request;		   
static tSmbNtlmAuthChallenge challenge;
static tSmbNtlmAuthResponse  response;

/*
 * NTLM support by Grant Edwards.
 *
 * Handle MS-Exchange NTLM authentication method.  This is the same
 * as the NTLM auth used by Samba for SMB related services. We just
 * encode the packets in base64 instead of sending them out via a
 * network interface.
 * 
 * Much source (ntlm.h, smb*.c smb*.h) was borrowed from Samba.
 */

static int do_imap_ntlm(int sock, struct query *ctl)
{
    char msgbuf[2048];
    int result,len;
  
    gen_send(sock, "AUTHENTICATE NTLM");

    if ((result = gen_recv(sock, msgbuf, sizeof msgbuf)))
	return result;
  
    if (msgbuf[0] != '+')
	return PS_AUTHFAIL;
  
    buildSmbNtlmAuthRequest(&request,ctl->remotename,NULL);

    if (outlevel >= O_DEBUG)
	dumpSmbNtlmAuthRequest(stdout, &request);

    memset(msgbuf,0,sizeof msgbuf);
    to64frombits (msgbuf, (unsigned char*)&request, SmbLength(&request));
  
    if (outlevel >= O_MONITOR)
	report(stdout, "IMAP> %s\n", msgbuf);
  
    strcat(msgbuf,"\r\n");
    SockWrite (sock, msgbuf, strlen (msgbuf));

    if ((gen_recv(sock, msgbuf, sizeof msgbuf)))
	return result;
  
    len = from64tobits ((unsigned char*)&challenge, msgbuf, sizeof(msgbuf));
    
    if (outlevel >= O_DEBUG)
	dumpSmbNtlmAuthChallenge(stdout, &challenge);
    
    buildSmbNtlmAuthResponse(&challenge, &response,ctl->remotename,ctl->password);
  
    if (outlevel >= O_DEBUG)
	dumpSmbNtlmAuthResponse(stdout, &response);
  
    memset(msgbuf,0,sizeof msgbuf);
    to64frombits (msgbuf, (unsigned char*)&response, SmbLength(&response));

    if (outlevel >= O_MONITOR)
	report(stdout, "IMAP> %s\n", msgbuf);
      
    strcat(msgbuf,"\r\n");
    SockWrite (sock, msgbuf, strlen (msgbuf));
  
    if ((result = gen_recv (sock, msgbuf, sizeof msgbuf)))
	return result;
  
    if (strstr (msgbuf, "OK"))
	return PS_SUCCESS;
    else
	return PS_AUTHFAIL;
}
#endif /* NTLM */

static int imap_canonicalize(char *result, char *raw, int maxlen)
/* encode an IMAP password as per RFC1730's quoting conventions */
{
    int i, j;

    j = 0;
    for (i = 0; i < strlen(raw) && i < maxlen; i++)
    {
	if ((raw[i] == '\\') || (raw[i] == '"'))
	    result[j++] = '\\';
	result[j++] = raw[i];
    }
    result[j] = '\0';

    return(i);
}

static int imap_getauth(int sock, struct query *ctl, char *greeting)
/* apply for connection authorization */
{
    int ok = 0;

    /* probe to see if we're running IMAP4 and can use RFC822.PEEK */
    capabilities[0] = '\0';
    if ((ok = gen_transact(sock, "CAPABILITY")) == PS_SUCCESS)
    {
	char	*cp;

	/* capability checks are supposed to be caseblind */
	for (cp = capabilities; *cp; cp++)
	    *cp = toupper(*cp);

	/* UW-IMAP server 10.173 notifies in all caps, but RFC2060 says we
	   should expect a response in mixed-case */
	if (strstr(capabilities, "IMAP4REV1"))
	{
	    imap_version = IMAP4rev1;
	    if (outlevel >= O_DEBUG)
		report(stdout, GT_("Protocol identified as IMAP4 rev 1\n"));
	}
	else
	{
	    imap_version = IMAP4;
	    if (outlevel >= O_DEBUG)
		report(stdout, GT_("Protocol identified as IMAP4 rev 0\n"));
	}
    }
    else if (ok == PS_ERROR)
    {
	imap_version = IMAP2;
	if (outlevel >= O_DEBUG)
	    report(stdout, GT_("Protocol identified as IMAP2 or IMAP2BIS\n"));
    }
    else
	return(ok);

    peek_capable = (imap_version >= IMAP4);

    /* 
     * Assumption: expunges are cheap, so we want to do them
     * after every message unless user said otherwise.
     */
    if (NUM_SPECIFIED(ctl->expunge))
	expunge_period = NUM_VALUE_OUT(ctl->expunge);
    else
	expunge_period = 1;

    /* 
     * Handle idling.  We depend on coming through here on startup
     * and after each timeout (including timeouts during idles).
     */
    if (strstr(capabilities, "IDLE") && ctl->idle)
    {
	do_idle = TRUE;
	if (outlevel >= O_VERBOSE)
	    report(stdout, GT_("will idle after poll\n"));
    }

    /* 
     * If either (a) we saw a PREAUTH token in the greeting, or
     * (b) the user specified ssh preauthentication, then we're done.
     */
    if (preauth || ctl->server.authenticate == A_SSH)
    {
        preauth = FALSE;  /* reset for the next session */
        return(PS_SUCCESS);
    }

    /*
     * Time to authenticate the user.
     * Try the protocol variants that don't require passwords first.
     */
    ok = PS_AUTHFAIL;

#ifdef GSSAPI
    if ((ctl->server.authenticate == A_ANY 
	 || ctl->server.authenticate == A_GSSAPI)
	&& strstr(capabilities, "AUTH=GSSAPI"))
	if(ok = do_gssauth(sock, "AUTHENTICATE", ctl->server.truename, ctl->remotename))
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return ok;
#endif /* GSSAPI */

#ifdef KERBEROS_V4
    if ((ctl->server.authenticate == A_ANY 
	 || ctl->server.authenticate == A_KERBEROS_V4
	 || ctl->server.authenticate == A_KERBEROS_V5) 
	&& strstr(capabilities, "AUTH=KERBEROS_V4"))
    {
	if ((ok = do_rfc1731(sock, "AUTHENTICATE", ctl->server.truename)))
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return ok;
    }
#endif /* KERBEROS_V4 */

    /*
     * No such luck.  OK, now try the variants that mask your password
     * in a challenge-response.
     */

    if ((ctl->server.authenticate == A_ANY 
	 || ctl->server.authenticate == A_CRAM_MD5)
	&& strstr(capabilities, "AUTH=CRAM-MD5"))
    {
	if ((ok = do_cram_md5 (sock, "AUTHENTICATE", ctl, NULL)))
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return ok;
    }

#if OPIE_ENABLE
    if ((ctl->server.authenticate == A_ANY 
	 || ctl->server.authenticate == A_OTP)
	&& strstr(capabilities, "AUTH=X-OTP"))
	if ((ok = do_otp(sock, "AUTHENTICATE", ctl)))
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return ok;
#else
    if (ctl->server.authenticate == A_OTP)
    {
	report(stderr, 
	   GT_("Required OTP capability not compiled into fetchmail\n"));
    }
#endif /* OPIE_ENABLE */

#ifdef NTLM_ENABLE
    if ((ctl->server.authenticate == A_ANY 
	 || ctl->server.authenticate == A_NTLM) 
	&& strstr (capabilities, "AUTH=NTLM")) {
	if ((ok = do_imap_ntlm(sock, ctl)))
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return(ok);
    }
#else
    if (ctl->server.authenticate == A_NTLM)
    {
	report(stderr, 
	   GT_("Required NTLM capability not compiled into fetchmail\n"));
    }
#endif /* NTLM_ENABLE */

#ifdef __UNUSED__	/* The Cyrus IMAP4rev1 server chokes on this */
    /* this handles either AUTH=LOGIN or AUTH-LOGIN */
    if ((imap_version >= IMAP4rev1) && (!strstr(capabilities, "LOGIN")))
    {
	report(stderr, 
	       GT_("Required LOGIN capability not supported by server\n"));
    }
#endif /* __UNUSED__ */

    /* we're stuck with sending the password en clair */
    if ((ctl->server.authenticate == A_ANY 
 	 || ctl->server.authenticate == A_PASSWORD) 
 	&& !strstr (capabilities, "LOGINDISABLED"))
    {
	/* these sizes guarantee no buffer overflow */
	char	remotename[NAMELEN*2+1], password[PASSWORDLEN*2+1];

	imap_canonicalize(remotename, ctl->remotename, NAMELEN);
	imap_canonicalize(password, ctl->password, PASSWORDLEN);

	strcpy(shroud, password);
	ok = gen_transact(sock, "LOGIN \"%s\" \"%s\"", remotename, password);
	shroud[0] = '\0';
	if (ok)
	{
	    /* SASL cancellation of authentication */
	    gen_send(sock, "*");
	    if(ctl->server.authenticate != A_ANY)
                return ok;
	}
	else
	    return(ok);
    }

    return(ok);
}

static int internal_expunge(int sock)
/* ship an expunge, resetting associated counters */
{
    int	ok;

    if ((ok = gen_transact(sock, "EXPUNGE")))
	return(ok);

    expunged += deletions;
    deletions = 0;

#ifdef IMAP_UID	/* not used */
    expunge_uids(ctl);
#endif /* IMAP_UID */

    return(PS_SUCCESS);
}

static int imap_idle(int sock)
/* start an RFC2177 IDLE */
{
    stage = STAGE_IDLE;
    saved_timeout = mytimeout;
    mytimeout = 0;

    return (gen_transact(sock, "IDLE"));
}

static int imap_getrange(int sock, 
			 struct query *ctl, 
			 const char *folder, 
			 int *countp, int *newp, int *bytes)
/* get range of messages to be fetched */
{
    int ok;
    char buf[MSGBUFSIZE+1], *cp;

    /* find out how many messages are waiting */
    *bytes = -1;

    if (pass > 1)
    {
	/* 
	 * We have to have an expunge here, otherwise the re-poll will
	 * infinite-loop picking up un-expunged messages -- unless the
	 * expunge period is one and we've been nuking each message 
	 * just after deletion.
	 */
	ok = 0;
	if (deletions) {
	    ok = internal_expunge(sock);
	    if (ok)
	    {
		report(stderr, GT_("expunge failed\n"));
		return(ok);
	    }
	}

	/*
	 * recentcount is already set here by the last imap command which
	 * returned RECENT on detecting new mail. if recentcount is 0, wait
	 * for new mail.
	 */

	/* this is a while loop because imap_idle() might return on other
	 * mailbox changes also */
	while (recentcount == 0 && do_idle) {
	    smtp_close(ctl, 1);
	    ok = imap_idle(sock);
	    if (ok)
	    {
		report(stderr, GT_("re-poll failed\n"));
		return(ok);
	    }
	}
	/* if recentcount is 0, return no mail */
	if (recentcount == 0)
		count = 0;
	if (outlevel >= O_DEBUG)
	    report(stdout, GT_("%d messages waiting after re-poll\n"), count);
    }
    else
    {
	count = 0;
	ok = gen_transact(sock, 
			  check_only ? "EXAMINE \"%s\"" : "SELECT \"%s\"",
			  folder ? folder : "INBOX");
	if (ok != 0)
	{
	    report(stderr, GT_("mailbox selection failed\n"));
	    return(ok);
	}
	else if (outlevel >= O_DEBUG)
	    report(stdout, GT_("%d messages waiting after first poll\n"), count);

	/* no messages?  then we may need to idle until we get some */
	while (count == 0 && do_idle) {
	    ok = imap_idle(sock);
	    if (ok)
	    {
		report(stderr, GT_("re-poll failed\n"));
		return(ok);
	    }
	}

	/*
	 * We should have an expunge here to
	 * a) avoid fetching deleted mails during 'fetchall'
	 * b) getting a wrong count of mails during 'no fetchall'
	 */
	if (!check_only && !ctl->keep && count > 0)
	{
	    ok = internal_expunge(sock);
	    if (ok)
	    {
		report(stderr, GT_("expunge failed\n"));
		return(ok);
	    }
	    if (outlevel >= O_DEBUG)
		report(stdout, GT_("%d messages waiting after expunge\n"), count);
	}
    }

    *countp = count;
    recentcount = 0;

    /* OK, now get a count of unseen messages and their indices */
    if (!ctl->fetchall && count > 0)
    {
	if (unseen_messages)
	    free(unseen_messages);
	unseen_messages = xmalloc(count * sizeof(unsigned int));
	memset(unseen_messages, 0, count * sizeof(unsigned int));
	unseen = 0;

	gen_send(sock, "SEARCH UNSEEN");
	do {
	    ok = gen_recv(sock, buf, sizeof(buf));
	    if (ok != 0)
	    {
		report(stderr, GT_("search for unseen messages failed\n"));
		return(PS_PROTOCOL);
	    }
	    else if ((cp = strstr(buf, "* SEARCH")))
	    {
		char	*ep;

		cp += 8;	/* skip "* SEARCH" */

		while (*cp && unseen < count)
		{
		    /* skip whitespace */
		    while (*cp && isspace(*cp))
			cp++;
		    if (*cp) 
		    {
			/*
			 * Message numbers are between 1 and 2^32 inclusive,
			 * so unsigned int is large enough.
			 */
			unseen_messages[unseen]=(unsigned int)strtol(cp,&ep,10);

			if (outlevel >= O_DEBUG)
			    report(stdout, 
				   GT_("%u is unseen\n"), 
				   unseen_messages[unseen]);
		
			unseen++;
			cp = ep;
		    }
		}
	    }
	} while
	    (tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));
    } else
	unseen = -1;

    *newp = unseen;
    count = 0;
    expunged = 0;
    deletions = 0;

    return(PS_SUCCESS);
}

static int imap_getsizes(int sock, int count, int *sizes)
/* capture the sizes of all messages */
{
    char buf [MSGBUFSIZE+1];

    /*
     * Some servers (as in, PMDF5.1-9.1 under OpenVMS 6.1)
     * won't accept 1:1 as valid set syntax.  Some implementors
     * should be taken out and shot for excessive anality.
     *
     * Microsoft Exchange (brain-dead piece of crap that it is) 
     * sometimes gets its knickers in a knot about bodiless messages.
     * You may see responses like this:
     *
     *	fetchmail: IMAP> A0004 FETCH 1:9 RFC822.SIZE
     *	fetchmail: IMAP< * 2 FETCH (RFC822.SIZE 1187)
     *	fetchmail: IMAP< * 3 FETCH (RFC822.SIZE 3954)
     *	fetchmail: IMAP< * 4 FETCH (RFC822.SIZE 1944)
     *	fetchmail: IMAP< * 5 FETCH (RFC822.SIZE 2933)
     *	fetchmail: IMAP< * 6 FETCH (RFC822.SIZE 1854)
     *	fetchmail: IMAP< * 7 FETCH (RFC822.SIZE 34054)
     *	fetchmail: IMAP< * 8 FETCH (RFC822.SIZE 5561)
     *	fetchmail: IMAP< * 9 FETCH (RFC822.SIZE 1101)
     *	fetchmail: IMAP< A0004 NO The requested item could not be found.
     *
     * This means message 1 has only headers.  For kicks and grins
     * you can telnet in and look:
     *	A003 FETCH 1 FULL
     *	A003 NO The requested item could not be found.
     *	A004 fetch 1 rfc822.header
     *	A004 NO The requested item could not be found.
     *	A006 FETCH 1 BODY
     *	* 1 FETCH (BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 35 3))
     *	A006 OK FETCH completed.
     *
     * To get around this, we terminate the read loop on a NO and count
     * on the fact that the sizes array has been preinitialized with a
     * known-bad size value.
     */
    if (count == 1)
	gen_send(sock, "FETCH 1 RFC822.SIZE");
    else
	gen_send(sock, "FETCH 1:%d RFC822.SIZE", count);
    for (;;)
    {
	unsigned int num, size;
	int ok;

	if ((ok = gen_recv(sock, buf, sizeof(buf))))
	    return(ok);
	else if (strstr(buf, "OK") || strstr(buf, "NO"))
	    break;
	else if (sscanf(buf, "* %u FETCH (RFC822.SIZE %u)", &num, &size) == 2) {
	    if (num > 0 && num <= count)
	        sizes[num - 1] = size;
	    else
		report(stderr, "Warning: ignoring bogus data for message sizes returned by the server.\n");
	}
    }

    return(PS_SUCCESS);
}

static int imap_is_old(int sock, struct query *ctl, int number)
/* is the given message old? */
{
    flag seen = TRUE;
    int i;

    /* 
     * Expunges change the fetch numbers, but unseen_messages contains
     * indices from before any expungees were done.  So neither the
     * argument nor the values in message_sequence need to be decremented.
     */

    seen = TRUE;
    for (i = 0; i < unseen; i++)
	if (unseen_messages[i] == number)
	{
	    seen = FALSE;
	    break;
	}

    return(seen);
}

static char *skip_token(char *ptr)
{
    while(isspace(*ptr)) ptr++;
    while(!isspace(*ptr) && !iscntrl(*ptr)) ptr++;
    while(isspace(*ptr)) ptr++;
    return(ptr);
}

static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
/* request headers of nth message */
{
    char buf [MSGBUFSIZE+1];
    int	num;

    /* expunges change the fetch numbers */
    number -= expunged;

    /*
     * This is blessed by RFC1176, RFC1730, RFC2060.
     * According to the RFCs, it should *not* set the \Seen flag.
     */
    gen_send(sock, "FETCH %d RFC822.HEADER", number);

    /* looking for FETCH response */
    for (;;) 
    {
	int	ok;
	char	*ptr;

	if ((ok = gen_recv(sock, buf, sizeof(buf))))
	    return(ok);
 	ptr = skip_token(buf);	/* either "* " or "AXXXX " */
 	if (sscanf(ptr, "%d FETCH (%*s {%d}", &num, lenp) == 2)
  	    break;
	/* try to recover from chronically fucked-up M$ Exchange servers */
 	else if (!strncmp(ptr, "NO", 2))
 	    return(PS_TRANSIENT);
 	else if (!strncmp(ptr, "BAD", 3))
 	    return(PS_TRANSIENT);
    }

    if (num != number)
	return(PS_ERROR);
    else
	return(PS_SUCCESS);
}

static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
/* request body of nth message */
{
    char buf [MSGBUFSIZE+1], *cp;
    int	num;

    /* expunges change the fetch numbers */
    number -= expunged;

    /*
     * If we're using IMAP4, we can fetch the message without setting its
     * seen flag.  This is good!  It means that if the protocol exchange
     * craps out during the message, it will still be marked `unseen' on
     * the server.
     *
     * However...*don't* do this if we're using keep to suppress deletion!
     * In that case, marking the seen flag is the only way to prevent the
     * message from being re-fetched on subsequent runs (and according
     * to RFC2060 p.43 this fetch should set Seen as a side effect).
     *
     * According to RFC2060, and Mark Crispin the IMAP maintainer,
     * FETCH %d BODY[TEXT] and RFC822.TEXT are "functionally 
     * equivalent".  However, we know of at least one server that
     * treats them differently in the presence of MIME attachments;
     * the latter form downloads the attachment, the former does not.
     * The server is InterChange, and the fool who implemented this
     * misfeature ought to be strung up by his thumbs.  
     *
     * When I tried working around this by disabling use of the 4rev1 form,
     * I found that doing this breaks operation with M$ Exchange.
     * Annoyingly enough, Exchange's refusal to cope is technically legal
     * under RFC2062.  Trust Microsoft, the Great Enemy of interoperability
     * standards, to find a way to make standards compliance irritating....
     */
    switch (imap_version)
    {
    case IMAP4rev1:	/* RFC 2060 */
	if (!ctl->keep)
	    gen_send(sock, "FETCH %d BODY.PEEK[TEXT]", number);
	else
	    gen_send(sock, "FETCH %d BODY[TEXT]", number);
	break;

    case IMAP4:		/* RFC 1730 */
	if (!ctl->keep)
	    gen_send(sock, "FETCH %d RFC822.TEXT.PEEK", number);
	else
	    gen_send(sock, "FETCH %d RFC822.TEXT", number);
	break;

    default:		/* RFC 1176 */
	gen_send(sock, "FETCH %d RFC822.TEXT", number);
	break;
    }

    /* looking for FETCH response */
    do {
	int	ok;

	if ((ok = gen_recv(sock, buf, sizeof(buf))))
	    return(ok);
    } while
	(!strstr(buf+4, "FETCH") || sscanf(buf+2, "%d", &num) != 1);

    if (num != number)
	return(PS_ERROR);

    /*
     * Try to extract a length from the FETCH response.  RFC2060 requires
     * it to be present, but at least one IMAP server (Novell GroupWise)
     * botches this.
     */
    if ((cp = strchr(buf, '{')))
	*lenp = atoi(cp + 1);
    else
	*lenp = -1;	/* missing length part in FETCH reponse */

    return(PS_SUCCESS);
}

static int imap_trail(int sock, struct query *ctl, int number)
/* discard tail of FETCH response after reading message text */
{
    /* expunges change the fetch numbers */
    /* number -= expunged; */

    for (;;)
    {
	char buf[MSGBUFSIZE+1];
	int ok;

	if ((ok = gen_recv(sock, buf, sizeof(buf))))
	    return(ok);

	/* UW IMAP returns "OK FETCH", Cyrus returns "OK Completed" */
	if (strstr(buf, "OK"))
	    break;

#ifdef __UNUSED__
	/*
	 * Any IMAP server that fails to set Seen on a BODY[TEXT]
	 * fetch violates RFC2060 p.43 (top).  This becomes an issue
	 * when keep is on, because seen messages aren't deleted and
	 * get refetched on each poll.  As a workaround, if keep is on
	 * we can set the Seen flag explicitly.
	 *
	 * This code isn't used yet because we don't know of any IMAP
	 * servers broken in this way.
	 */
	if (ctl->keep)
	    if ((ok = gen_transact(sock,
			imap_version == IMAP4 
				? "STORE %d +FLAGS.SILENT (\\Seen)"
				: "STORE %d +FLAGS (\\Seen)", 
			number)))
		return(ok);
#endif /* __UNUSED__ */
    }

    return(PS_SUCCESS);
}

static int imap_delete(int sock, struct query *ctl, int number)
/* set delete flag for given message */
{
    int	ok;

    /* expunges change the fetch numbers */
    number -= expunged;

    /*
     * Use SILENT if possible as a minor throughput optimization.
     * Note: this has been dropped from IMAP4rev1.
     *
     * We set Seen because there are some IMAP servers (notably HP
     * OpenMail) that do message-receipt DSNs, but only when the seen
     * bit is set.  This is the appropriate time -- we get here right
     * after the local SMTP response that says delivery was
     * successful.
     */
    if ((ok = gen_transact(sock,
			imap_version == IMAP4 
				? "STORE %d +FLAGS.SILENT (\\Seen \\Deleted)"
				: "STORE %d +FLAGS (\\Seen \\Deleted)", 
			number)))
	return(ok);
    else
	deletions++;

    /*
     * We do an expunge after expunge_period messages, rather than
     * just before quit, so that a line hit during a long session
     * won't result in lots of messages being fetched again during
     * the next session.
     */
    if (NUM_NONZERO(expunge_period) && (deletions % expunge_period) == 0)
	internal_expunge(sock);

    return(PS_SUCCESS);
}

static int imap_logout(int sock, struct query *ctl)
/* send logout command */
{
    /* if any un-expunged deletions remain, ship an expunge now */
    if (deletions)
	internal_expunge(sock);

#ifdef USE_SEARCH
    /* Memory clean-up */
    if (unseen_messages)
	free(unseen_messages);
#endif /* USE_SEARCH */

    return(gen_transact(sock, "LOGOUT"));
}

const static struct method imap =
{
    "IMAP",		/* Internet Message Access Protocol */
#if INET6_ENABLE
    "imap",
    "imaps",
#else /* INET6_ENABLE */
    143,                /* standard IMAP2bis/IMAP4 port */
    993,                /* ssl IMAP2bis/IMAP4 port */
#endif /* INET6_ENABLE */
    TRUE,		/* this is a tagged protocol */
    FALSE,		/* no message delimiter */
    imap_ok,		/* parse command response */
    imap_getauth,	/* get authorization */
    imap_getrange,	/* query range of messages */
    imap_getsizes,	/* get sizes of messages (used for ESMTP SIZE option) */
    imap_is_old,	/* no UID check */
    imap_fetch_headers,	/* request given message headers */
    imap_fetch_body,	/* request given message body */
    imap_trail,		/* eat message trailer */
    imap_delete,	/* delete the message */
    imap_logout,	/* expunge and exit */
    TRUE,		/* yes, we can re-poll */
};

int doIMAP(struct query *ctl)
/* retrieve messages using IMAP Version 2bis or Version 4 */
{
    return(do_protocol(ctl, &imap));
}

/* imap.c ends here */