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[~andy/fetchmail] / driver.c

/*
 * driver.c -- generic driver for mail fetch method protocols
 *
 * Copyright 1997 by Eric S. Raymond
 * For license terms, see the file COPYING in this directory.
 */

#include  "config.h"
#include  <stdio.h>
#include  <setjmp.h>
#include  <errno.h>
#include  <ctype.h>
#include  <string.h>
#ifdef HAVE_MEMORY_H
#include  <memory.h>
#endif /* HAVE_MEMORY_H */
#if defined(STDC_HEADERS)
#include  <stdlib.h>
#endif
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if defined(HAVE_STDARG_H)
#include  <stdarg.h>
#else
#include  <varargs.h>
#endif
#if defined(HAVE_SYS_ITIMER_H)
#include <sys/itimer.h>
#endif
#include  <sys/time.h>
#include  <signal.h>

#ifdef HAVE_RES_SEARCH
#include <netdb.h>
#include "mx.h"
#endif /* HAVE_RES_SEARCH */

#ifdef KERBEROS_V4
#ifdef KERBEROS_V5
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
#else
#if defined (__bsdi__)
#include <des.h> /* order of includes matters */
#include <krb.h>
#define krb_get_err_text(e) (krb_err_txt[e])
#else
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__)
#define krb_get_err_text(e) (krb_err_txt[e])
#include <krb.h>
#include <des.h>
#else
#include <krb.h>
#include <des.h>
#endif /* ! defined (__FreeBSD__) */
#endif /* ! defined (__bsdi__) */
#endif /* KERBEROS_V5 */
#include <netinet/in.h>
#include <netdb.h>
#endif /* KERBEROS_V4 */
#ifdef KERBEROS_V5
#include <krb5.h>
#include <com_err.h>
#endif /* KERBEROS_V5 */
#include "i18n.h"

#include "socket.h"
#include "fetchmail.h"
#include "tunable.h"

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

int fetchlimit;         /* how often to tear down the server connection */
int batchcount;         /* count of messages sent in current batch */
flag peek_capable;      /* can we peek for better error recovery? */
int pass;               /* how many times have we re-polled? */
int phase;              /* where are we, for error-logging purposes? */

static const struct method *protocol;
static jmp_buf  restart;

char tag[TAGLEN];
static int tagnum;
#define GENSYM  (sprintf(tag, "A%04d", ++tagnum % TAGMOD), tag)

static char shroud[PASSWORDLEN];        /* string to shroud in debug output */
static int mytimeout;                   /* value of nonreponse timeout */
static int timeoutcount;                /* count consecutive timeouts */
static int msglen;                      /* actual message length */

void set_timeout(int timeleft)
/* reset the nonresponse-timeout */
{
#ifndef __EMX__
    struct itimerval ntimeout;

    if (timeleft == 0)
        timeoutcount = 0;

    ntimeout.it_interval.tv_sec = ntimeout.it_interval.tv_usec = 0;
    ntimeout.it_value.tv_sec  = timeleft;
    ntimeout.it_value.tv_usec = 0;
    setitimer(ITIMER_REAL, &ntimeout, (struct itimerval *)NULL);
#endif
}

static void timeout_handler (int signal)
/* handle server-timeout SIGALRM signal */
{
    timeoutcount++;
    longjmp(restart, 1);
}

static int accept_count, reject_count;

static void map_name(const char *name, struct query *ctl, struct idlist **xmit_names)
/* add given name to xmit_names if it matches declared localnames */
/*   name:       name to map */
/*   ctl:        list of permissible aliases */
/*   xmit_names: list of recipient names parsed out */
{
    const char  *lname;
    int off = 0;
    
    lname = idpair_find(&ctl->localnames, name+off);
    if (!lname && ctl->wildcard)
        lname = name+off;

    if (lname != (char *)NULL)
    {
        if (outlevel >= O_DEBUG)
            error(0, 0, _("mapped %s to local %s"), name, lname);
        save_str(xmit_names, lname, XMIT_ACCEPT);
        accept_count++;
    }
}

static void find_server_names(const char *hdr,
                              struct query *ctl,
                              struct idlist **xmit_names)
/* parse names out of a RFC822 header into an ID list */
/*   hdr:               RFC822 header in question */
/*   ctl:               list of permissible aliases */
/*   xmit_names:        list of recipient names parsed out */
{
    if (hdr == (char *)NULL)
        return;
    else
    {
        char    *cp;

        for (cp = nxtaddr(hdr);
             cp != NULL;
             cp = nxtaddr(NULL))
        {
            char        *atsign;

            /*
             * If the name of the user begins with a qmail virtual
             * domain prefix, ignore the prefix.  Doing this here
             * means qvirtual will work either with ordinary name
             * mapping or with a localdomains option.
             */
            if (ctl->server.qvirtual)
            {
                int sl = strlen(ctl->server.qvirtual);
 
                if (!strncasecmp(cp, ctl->server.qvirtual, sl))
                    cp += sl;
            }

            if ((atsign = strchr(cp, '@'))) {
                struct idlist   *idp;

                /*
                 * Does a trailing segment of the hostname match something
                 * on the localdomains list?  If so, save the whole name
                 * and keep going.
                 */
                for (idp = ctl->server.localdomains; idp; idp = idp->next) {
                    char        *rhs;

                    rhs = atsign + (strlen(atsign) - strlen(idp->id));
                    if (rhs > atsign &&
                        (rhs[-1] == '.' || rhs[-1] == '@') &&
                        strcasecmp(rhs, idp->id) == 0)
                    {
                        if (outlevel >= O_DEBUG)
                            error(0, 0, _("passed through %s matching %s"), 
                                  cp, idp->id);
                        save_str(xmit_names, cp, XMIT_ACCEPT);
                        accept_count++;
                        goto nomap;
                    }
                }

                /* if we matched a local domain, idp != NULL */
                if (!idp)
                {
                    /*
                     * Check to see if the right-hand part is an alias
                     * or MX equivalent of the mailserver.  If it's
                     * not, skip this name.  If it is, we'll keep
                     * going and try to find a mapping to a client name.
                     */
                    if (!is_host_alias(atsign+1, ctl))
                    {
                        save_str(xmit_names, cp, XMIT_REJECT);
                        reject_count++;
                        continue;
                    }
                }
                atsign[0] = '\0';
                map_name(cp, ctl, xmit_names);
            nomap:;
            }
        }
    }
}

static char *parse_received(struct query *ctl, char *bufp)
/* try to extract real address from the Received line */
/* If a valid Received: line is found, we return the full address in
 * a buffer which can be parsed from nxtaddr().  This is to ansure that
 * the local domain part of the address can be passed along in 
 * find_server_names() if it contains one.
 * Note: We should return a dummy header containing the address 
 * which makes nxtaddr() behave correctly. 
 */
{
    char *base, *ok = (char *)NULL;
    static char rbuf[HOSTLEN + USERNAMELEN + 4]; 

    /*
     * Try to extract the real envelope addressee.  We look here
     * specifically for the mailserver's Received line.
     * Note: this will only work for sendmail, or an MTA that
     * shares sendmail's convention for embedding the envelope
     * address in the Received line.  Sendmail itself only
     * does this when the mail has a single recipient.
     */
    if (outlevel >= O_DEBUG)
        error(0, 0, _("analyzing Received line:\n%s"), bufp);

    /* search for whitepace-surrounded "by" followed by xxxx.yyyy */
    for (base = bufp;  ; base = ok + 2)
    {
        if (!(ok = strstr(base, "by")))
            break;
        else if (!isspace(ok[-1]) || !isspace(ok[2]))
            continue;
        else
        {
            char        *sp, *tp;

            /* extract space-delimited token after "by" */
            for (sp = ok + 2; isspace(*sp); sp++)
                continue;
            tp = rbuf;
            for (; !isspace(*sp); sp++)
                *tp++ = *sp;
            *tp = '\0';

            /* look for embedded periods */
            if (strchr(rbuf, '.'))
                break;
            else
                ok = sp - 1;    /* arrange to skip this token */
        }
    }
    if (ok)
    {
        /*
         * If it's a DNS name of the mail server, look for the
         * recipient name after a following "for".  Otherwise
         * punt.
         */
        if (is_host_alias(rbuf, ctl))
        {
            if (outlevel >= O_DEBUG)
                error(0, 0, 
                      _("line accepted, %s is an alias of the mailserver"), rbuf);
        }
        else
        {
            if (outlevel >= O_DEBUG)
                error(0, 0, 
                      _("line rejected, %s is not an alias of the mailserver"), 
                      rbuf);
            return(NULL);
        }

        /* search for whitepace-surrounded "for" followed by xxxx@yyyy */
        for (base = ok + 4 + strlen(rbuf);  ; base = ok + 2)
        {
            if (!(ok = strstr(base, "for")))
                break;
            else if (!isspace(ok[-1]) || !isspace(ok[3]))
                continue;
            else
            {
                char    *sp, *tp;

                /* extract space-delimited token after "for" */
                for (sp = ok + 3; isspace(*sp); sp++)
                    continue;
                tp = rbuf;
                for (; !isspace(*sp); sp++)
                    *tp++ = *sp;
                *tp = '\0';

                if (strchr(rbuf, '@'))
                    break;
                else
                    ok = sp - 1;        /* arrange to skip this token */
            }
        }
        if (ok)
        {
            flag        want_gt = FALSE;
            char        *sp, *tp;

            /* char after "for" could be space or a continuation newline */
            for (sp = ok + 4; isspace(*sp); sp++)
                continue;
            tp = rbuf;
            *tp++ = ':';        /* Here is the hack.  This is to be friends */
            *tp++ = ' ';        /* with nxtaddr()... */
            if (*sp == '<')
            {
                want_gt = TRUE;
                sp++;
            }
            while (*sp == '@')          /* skip routes */
                while (*sp && *sp++ != ':')
                    continue;
            while (*sp
                   && (want_gt ? (*sp != '>') : !isspace(*sp))
                   && *sp != ';')
                if (!isspace(*sp))
                    *tp++ = *sp++;
                else
                {
                    /* uh oh -- whitespace here can't be right! */
                    ok = (char *)NULL;
                    break;
                }
            *tp++ = '\n';
            *tp = '\0';
            if (strlen(rbuf) <= 3)      /* apparently nothing has been found */
                ok = NULL;
        } else
            ok = (char *)NULL;
    }

    if (!ok)
    {
        if (outlevel >= O_DEBUG)
            error(0, 0, _("no Received address found"));
        return(NULL);
    }
    else
    {
        if (outlevel >= O_DEBUG) {
            char *lf = rbuf + strlen(rbuf)-1;
            *lf = '\0';
            if (outlevel >= O_DEBUG)
                error(0, 0, _("found Received address `%s'"), rbuf+2);
            *lf = '\n';
        }
        return(rbuf);
    }
}

/* shared by readheaders and readbody */
static int sizeticker;
static struct msgblk msgblk;

#define EMPTYLINE(s)    ((s)[0] == '\r' && (s)[1] == '\n' && (s)[2] == '\0')

static int readheaders(int sock,
                       long fetchlen,
                       long reallen,
                       struct query *ctl,
                       int num)
/* read message headers and ship to SMTP or MDA */
/*   sock:              to which the server is connected */
/*   fetchlen:          length of message according to fetch response */
/*   reallen:           length of message according to getsizes */
/*   ctl:               query control record */
/*   num:               index of message */
{
    struct addrblk
    {
        int             offset;
        struct addrblk  *next;
    };
    struct addrblk      *to_addrchain = NULL;
    struct addrblk      **to_chainptr = &to_addrchain;
    struct addrblk      *resent_to_addrchain = NULL;
    struct addrblk      **resent_to_chainptr = &resent_to_addrchain;

    char                buf[MSGBUFSIZE+1];
    int                 from_offs, reply_to_offs, resent_from_offs;
    int                 app_from_offs, sender_offs, resent_sender_offs;
    int                 env_offs;
    char                *received_for, *rcv, *cp;
    int                 n, linelen, oldlen, ch, remaining, skipcount;
    struct idlist       *idp;
    flag                no_local_matches = FALSE;
    flag                headers_ok, has_nuls;
    int                 olderrs, good_addresses, bad_addresses;

    sizeticker = 0;
    has_nuls = headers_ok = FALSE;
    msgblk.return_path[0] = '\0';
    olderrs = ctl->errcount;

    /* read message headers */
    msgblk.reallen = reallen;
    msgblk.headers = received_for = NULL;
    from_offs = reply_to_offs = resent_from_offs = app_from_offs = 
        sender_offs = resent_sender_offs = env_offs = -1;
    oldlen = 0;
    msglen = 0;
    skipcount = 0;
    ctl->mimemsg = 0;

    for (remaining = fetchlen; remaining > 0 || protocol->delimited; remaining -= linelen)
    {
        char *line;

        line = xmalloc(sizeof(buf));
        linelen = 0;
        line[0] = '\0';
        do {
            set_timeout(mytimeout);
            if ((n = SockRead(sock, buf, sizeof(buf)-1)) == -1) {
                set_timeout(0);
                free(line);
                free(msgblk.headers);
                return(PS_SOCKET);
            }
            set_timeout(0);
            linelen += n;
            msglen += n;

            /* lines may not be properly CRLF terminated; fix this for qmail */
            if (ctl->forcecr)
            {
                cp = buf + strlen(buf) - 1;
                if (*cp == '\n' && (cp == buf || cp[-1] != '\r'))
                {
                    *cp++ = '\r';
                    *cp++ = '\n';
                    *cp++ = '\0';
                }
            }


            line = (char *) realloc(line, strlen(line) + strlen(buf) +1);

            strcat(line, buf);

            /* check for end of headers */
            if (EMPTYLINE(line))
            {
                headers_ok = TRUE;
                has_nuls = (linelen != strlen(line));
                free(line);
                goto process_headers;
            }

            /*
             * Check for end of message immediately.  If one of your folders
             * has been mangled, the delimiter may occur directly after the
             * header.
             */
            if (protocol->delimited && line[0] == '.' && EMPTYLINE(line+1))
            {
                free(line);
                has_nuls = (linelen != strlen(line));
                goto process_headers;
            }

            /* check for RFC822 continuations */
            set_timeout(mytimeout);
            ch = SockPeek(sock);
            set_timeout(0);
        } while
            (ch == ' ' || ch == '\t');  /* continuation to next line? */

        /* write the message size dots */
        if ((outlevel > O_SILENT && outlevel < O_VERBOSE) && linelen > 0)
        {
            sizeticker += linelen;
            while (sizeticker >= SIZETICKER)
            {
                error_build(".");
                sizeticker -= SIZETICKER;
            }
        }

        /* we see an ordinary (non-header, non-message-delimiter line */
        has_nuls = (linelen != strlen(line));

        /*
         * The University of Washington IMAP server (the reference
         * implementation of IMAP4 written by Mark Crispin) relies
         * on being able to keep base-UID information in a special
         * message at the head of the mailbox.  This message should
         * neither be deleted nor forwarded.
         */
#ifdef POP2_ENABLE
        /*
         * We disable this check under POP2 because there's no way to
         * prevent deletion of the message.  So at least we ought to 
         * forward it to the user so he or she will have some clue
         * that things have gone awry.
         */
        if (protocol->port != 109)
#endif /* POP2_ENABLE */
            if (num == 1 && !strncasecmp(line, "X-IMAP:", 7)) {
                free(line);
                free(msgblk.headers);
                return(PS_RETAINED);
            }

        /*
         * This code prevents fetchmail from becoming an accessory after
         * the fact to upstream sendmails with the `E' option on.  It also
         * copes with certain brain-dead POP servers (like NT's) that pass
         * through Unix from_ lines.
         *
         * Either of these bugs can result in a non-RFC822 line at the
         * beginning of the headers.  If fetchmail just passes it
         * through, the client listener may think the message has *no*
         * headers (since the first) line it sees doesn't look
         * RFC822-conformant) and fake up a set.
         *
         * What the user would see in this case is bogus (synthesized)
         * headers, followed by a blank line, followed by the >From, 
         * followed by the real headers, followed by a blank line,
         * followed by text.
         *
         * We forestall this lossage by tossing anything that looks
         * like an escaped or passed-through From_ line in headers.
         * These aren't RFC822 so our conscience is clear...
         */
        if (!strncasecmp(line, ">From ", 6) || !strncasecmp(line, "From ", 5))
        {
            free(line);
            continue;
        }

        /*
         * If we see a Status line, it may have been inserted by an MUA
         * on the mail host, or it may have been inserted by the server
         * program after the headers in the transaction stream.  This
         * can actually hose some new-mail notifiers such as xbuffy,
         * which assumes any Status line came from a *local* MDA and
         * therefore indicates that the message has been seen.
         *
         * Some buggy POP servers (including at least the 3.3(20)
         * version of the one distributed with IMAP) insert empty
         * Status lines in the transaction stream; we'll chuck those
         * unconditionally.  Nonempty ones get chucked if the user
         * turns on the dropstatus flag.
         */
        {
            char        *cp;

            if (!strncasecmp(line, "Status:", 7))
                cp = line + 7;
            else if (!strncasecmp(line, "X-Mozilla-Status:", 17))
                cp = line + 17;
            else
                cp = NULL;
            if (cp) {
                while (*cp && isspace(*cp)) cp++;
                if (!*cp || ctl->dropstatus)
                {
                    free(line);
                    continue;
                }
            }
        }

        if (ctl->rewrite)
            line = reply_hack(line, ctl->server.truename);

        /*
         * OK, this is messy.  If we're forwarding by SMTP, it's the
         * SMTP-receiver's job (according to RFC821, page 22, section
         * 4.1.1) to generate a Return-Path line on final delivery.
         * The trouble is, we've already got one because the
         * mailserver's SMTP thought *it* was responsible for final
         * delivery.
         *
         * Stash away the contents of Return-Path (as modified by reply_hack)
         * for use in generating MAIL FROM later on, then prevent the header
         * from being saved with the others.  In effect, we strip it off here.
         *
         * If the SMTP server conforms to the standards, and fetchmail gets the
         * envelope sender from the Return-Path, the new Return-Path should be
         * exactly the same as the original one.
         *
         * We do *not* want to ignore empty Return-Path headers.  These should
         * be passed through as a way of indicating that a message should
         * not trigger bounces if delivery fails.  What we *do* need to do is
         * make sure we never try to rewrite such a blank Return-Path.  We
         * handle this with a check for <> in the rewrite logic above.
         */
        if (!strncasecmp("Return-Path:", line, 12) && (cp = nxtaddr(line)))
        {
            strcpy(msgblk.return_path, cp);
            if (!ctl->mda) {
                free(line);
                continue;
            }
        }

        if (!msgblk.headers)
        {
            oldlen = strlen(line);
            msgblk.headers = xmalloc(oldlen + 1);
            (void) strcpy(msgblk.headers, line);
            free(line);
            line = msgblk.headers;
        }
        else
        {
            int newlen;

            newlen = oldlen + strlen(line);
            msgblk.headers = (char *) realloc(msgblk.headers, newlen + 1);
            if (msgblk.headers == NULL) {
                free(line);
                return(PS_IOERR);
            }
            strcpy(msgblk.headers + oldlen, line);
            free(line);
            line = msgblk.headers + oldlen;
            oldlen = newlen;
        }

        if (!strncasecmp("From:", line, 5))
            from_offs = (line - msgblk.headers);
        else if (!strncasecmp("Reply-To:", line, 9))
            reply_to_offs = (line - msgblk.headers);
        else if (!strncasecmp("Resent-From:", line, 12))
            resent_from_offs = (line - msgblk.headers);
        else if (!strncasecmp("Apparently-From:", line, 16))
            app_from_offs = (line - msgblk.headers);
        else if (!strncasecmp("Sender:", line, 7))
            sender_offs = (line - msgblk.headers);
        else if (!strncasecmp("Resent-Sender:", line, 14))
            resent_sender_offs = (line - msgblk.headers);

        else if (!strncasecmp("Message-Id:", buf, 11))
        {
            if (ctl->server.uidl)
            {
                char id[IDLEN+1];

                buf[IDLEN+12] = 0;              /* prevent stack overflow */
                sscanf(buf+12, "%s", id);
                if (!str_find( &ctl->newsaved, num))
                {
                    struct idlist *new = save_str(&ctl->newsaved,id,UID_SEEN);
                    new->val.status.num = num;
                }
            }
        }

        else if (!MULTIDROP(ctl))
            continue;

        else if (!strncasecmp("To:", line, 3)
                        || !strncasecmp("Cc:", line, 3)
                        || !strncasecmp("Bcc:", line, 4)
                        || !strncasecmp("Apparently-To:", line, 14))
        {
            *to_chainptr = xmalloc(sizeof(struct addrblk));
            (*to_chainptr)->offset = (line - msgblk.headers);
            to_chainptr = &(*to_chainptr)->next; 
            *to_chainptr = NULL;
        }

        else if (!strncasecmp("Resent-To:", line, 10)
                        || !strncasecmp("Resent-Cc:", line, 10)
                        || !strncasecmp("Resent-Bcc:", line, 11))
        {
            *resent_to_chainptr = xmalloc(sizeof(struct addrblk));
            (*resent_to_chainptr)->offset = (line - msgblk.headers);
            resent_to_chainptr = &(*resent_to_chainptr)->next; 
            *resent_to_chainptr = NULL;
        }

        else if (ctl->server.envelope != STRING_DISABLED)
        {
            if (ctl->server.envelope 
                        && strcasecmp(ctl->server.envelope, "Received"))
            {
                if (env_offs == -1 && !strncasecmp(ctl->server.envelope,
                                                line,
                                                strlen(ctl->server.envelope)))
                {                               
                    if (skipcount++ != ctl->server.envskip)
                        continue;
                    env_offs = (line - msgblk.headers);
                }    
            }
            else if (!received_for && !strncasecmp("Received:", line, 9))
            {
                if (skipcount++ != ctl->server.envskip)
                    continue;
                received_for = parse_received(ctl, line);
            }
        }
    }

 process_headers:
    /*
     * We want to detect this early in case there are so few headers that the
     * dispatch logic barfs.
     */
    if (!headers_ok)
    {
        if (outlevel > O_SILENT)
            error(0,0,_("message delimiter found while scanning headers"));
    }

    /*
     * Hack time.  If the first line of the message was blank, with no headers
     * (this happens occasionally due to bad gatewaying software) cons up
     * a set of fake headers.  
     *
     * If you modify the fake header template below, be sure you don't
     * make either From or To address @-less, otherwise the reply_hack
     * logic will do bad things.
     */
    if (msgblk.headers == (char *)NULL)
    {
#ifdef HAVE_SNPRINTF
        snprintf(buf, sizeof(buf),
#else
        sprintf(buf, 
#endif /* HAVE_SNPRINTF */
        "From: FETCHMAIL-DAEMON\r\nTo: %s@%s\r\nSubject: Headerless mail from %s's mailbox on %s\r\n",
                user, fetchmailhost, ctl->remotename, ctl->server.truename);
        msgblk.headers = xstrdup(buf);
    }

    /*
     * We can now process message headers before reading the text.
     * In fact we have to, as this will tell us where to forward to.
     */

    /* Decode MIME encoded headers. We MUST do this before
     * looking at the Content-Type / Content-Transfer-Encoding
     * headers (RFC 2046).
     */
    if (ctl->mimedecode) {
        UnMimeHeader(msgblk.headers);
    }
    /* Check for MIME headers indicating possible 8-bit data */
    ctl->mimemsg = MimeBodyType(msgblk.headers, ctl->mimedecode);

    /*
     * If there is a Return-Path address on the message, this was
     * almost certainly the MAIL FROM address given the originating
     * sendmail.  This is the best thing to use for logging the
     * message origin (it sets up the right behavior for bounces and
     * mailing lists).  Otherwise, fall down to the next available 
     * envelope address (which is the most probable real sender).
     * *** The order is important! ***
     * This is especially useful when receiving mailing list
     * messages in multidrop mode.  if a local address doesn't
     * exist, the bounce message won't be returned blindly to the 
     * author or to the list itself but rather to the list manager
     * (ex: specified by "Sender:") which is much less annoying.  This 
     * is true for most mailing list packages.
     */
    if( !msgblk.return_path[0] ){
        char *ap = NULL;
        if (resent_sender_offs >= 0 && (ap = nxtaddr(msgblk.headers + resent_sender_offs)));
        else if (sender_offs >= 0 && (ap = nxtaddr(msgblk.headers + sender_offs)));
        else if (resent_from_offs >= 0 && (ap = nxtaddr(msgblk.headers + resent_from_offs)));
        else if (from_offs >= 0 && (ap = nxtaddr(msgblk.headers + from_offs)));
        else if (reply_to_offs >= 0 && (ap = nxtaddr(msgblk.headers + reply_to_offs)));
        else if (app_from_offs >= 0 && (ap = nxtaddr(msgblk.headers + app_from_offs)));
        if (ap) strcpy( msgblk.return_path, ap );
    }

    /* cons up a list of local recipients */
    msgblk.recipients = (struct idlist *)NULL;
    accept_count = reject_count = 0;
    /* is this a multidrop box? */
    if (MULTIDROP(ctl))
    {
        if (env_offs > -1)          /* We have the actual envelope addressee */
            find_server_names(msgblk.headers + env_offs, ctl, &msgblk.recipients);
        else if (received_for)
            /*
             * We have the Received for addressee.  
             * It has to be a mailserver address, or we
             * wouldn't have got here.
             * We use find_server_names() to let local 
             * hostnames go through.
             */
            find_server_names(received_for, ctl, &msgblk.recipients);
#ifdef SDPS_ENABLE
        else if (sdps_envto)
        {
            find_server_names(sdps_envto, ctl, &msgblk.recipients);
            free(sdps_envto);
        }
#endif /* SDPS_ENABLE */ 
        else
        {
            /*
             * We haven't extracted the envelope address.
             * So check all the "Resent-To" header addresses if 
             * they exist.  If and only if they don't, consider
             * the "To" adresses.
             */
            register struct addrblk *nextptr;
            if (resent_to_addrchain) {
                /* delete the "To" chain and substitute it 
                 * with the "Resent-To" list 
                 */
                while (to_addrchain) {
                    nextptr = to_addrchain->next;
                    free(to_addrchain);
                    to_addrchain = nextptr;
                }
                to_addrchain = resent_to_addrchain;
                resent_to_addrchain = NULL;
            }
            /* now look for remaining adresses */
            while (to_addrchain) {
                find_server_names(msgblk.headers+to_addrchain->offset, ctl, &msgblk.recipients);
                nextptr = to_addrchain->next;
                free(to_addrchain);
                to_addrchain = nextptr;
            }
        }
        if (!accept_count)
        {
            no_local_matches = TRUE;
            save_str(&msgblk.recipients, run.postmaster, XMIT_ACCEPT);
            if (outlevel >= O_DEBUG)
                error(0, 0, 
                      _("no local matches, forwarding to %s"),
                      run.postmaster);
        }
    }
    else        /* it's a single-drop box, use first localname */
        save_str(&msgblk.recipients, ctl->localnames->id, XMIT_ACCEPT);


    /*
     * Time to either address the message or decide we can't deliver it yet.
     */
    if (ctl->errcount > olderrs)        /* there were DNS errors above */
    {
        if (outlevel >= O_DEBUG)
            error(0,0, _("forwarding and deletion suppressed due to DNS errors"));
        free(msgblk.headers);
        free_str_list(&msgblk.recipients);
        return(PS_TRANSIENT);
    }
    else
    {
        /* set up stuffline() so we can deliver the message body through it */ 
        if ((n = open_sink(ctl, &msgblk,
                           &good_addresses, &bad_addresses)) != PS_SUCCESS)
        {
            free(msgblk.headers);
            free_str_list(&msgblk.recipients);
            return(n);
        }
    }

    n = 0;
    /*
     * Some server/sendmail combinations cause problems when our
     * synthetic Received line is before the From header.  Cope
     * with this...
     */
    if ((rcv = strstr(msgblk.headers, "Received:")) == (char *)NULL)
        rcv = msgblk.headers;
    /* handle ">Received:" lines too */
    while (rcv > msgblk.headers && rcv[-1] != '\n')
        rcv--;
    if (rcv > msgblk.headers)
    {
        char    c = *rcv;

        *rcv = '\0';
        n = stuffline(ctl, msgblk.headers);
        *rcv = c;
    }
    if (!run.invisible && n != -1)
    {
        /* utter any per-message Received information we need here */
        sprintf(buf, "Received: from %s\r\n", ctl->server.truename);
        n = stuffline(ctl, buf);
        if (n != -1)
        {
            /*
             * This header is technically invalid under RFC822.
             * POP3, IMAP, etc. are not legal mail-parameter values.
             *
             * We used to include ctl->remotename in this log line,
             * but this can be secure information that would be bad
             * to reveal.
             */
            sprintf(buf, "\tby %s with %s (fetchmail-%s)\r\n",
                    fetchmailhost,
                    protocol->name,
                    VERSION);
            n = stuffline(ctl, buf);
            if (n != -1)
            {
                buf[0] = '\t';
                if (good_addresses == 0)
                {
                    sprintf(buf+1, 
                            "for %s@%s (by default); ",
                            user, ctl->destaddr);
                }
                else if (good_addresses == 1)
                {
                    for (idp = msgblk.recipients; idp; idp = idp->next)
                        if (idp->val.status.mark == XMIT_ACCEPT)
                            break;      /* only report first address */
                    if (strchr(idp->id, '@'))
                        sprintf(buf+1, "for %s", idp->id);
                    else
                        /*
                         * This could be a bit misleading, as destaddr is
                         * the forwarding host rather than the actual 
                         * destination.  Most of the time they coincide.
                         */
                        sprintf(buf+1, "for %s@%s", idp->id, ctl->destaddr);
                    sprintf(buf+strlen(buf), " (%s); ",
                            MULTIDROP(ctl) ? "multi-drop" : "single-drop");
                }
                else
                    buf[1] = '\0';

                strcat(buf, rfc822timestamp());
                strcat(buf, "\r\n");
                n = stuffline(ctl, buf);
            }
        }
    }

    if (n != -1)
        n = stuffline(ctl, rcv);        /* ship out rest of msgblk.headers */

    if (n == -1)
    {
        error(0, errno, _("writing RFC822 msgblk.headers"));
        release_sink(ctl);
        free(msgblk.headers);
        free_str_list(&msgblk.recipients);
        return(PS_IOERR);
    }
    else if (!run.use_syslog && outlevel >= O_VERBOSE)
        fputs("#", stderr);

    /* write error notifications */
    if (no_local_matches || has_nuls || bad_addresses)
    {
        int     errlen = 0;
        char    errhd[USERNAMELEN + POPBUFSIZE], *errmsg;

        errmsg = errhd;
        (void) strcpy(errhd, "X-Fetchmail-Warning: ");
        if (no_local_matches)
        {
            if (reject_count != 1)
                strcat(errhd, _("no recipient addresses matched declared local names"));
            else
            {
                for (idp = msgblk.recipients; idp; idp = idp->next)
                    if (idp->val.status.mark == XMIT_REJECT)
                        break;
                sprintf(errhd+strlen(errhd), _("recipient address %s didn't match any local name"), idp->id);
            }
        }

        if (has_nuls)
        {
            if (errhd[sizeof("X-Fetchmail-Warning: ")])
                strcat(errhd, "; ");
            strcat(errhd, _("message has embedded NULs"));
        }

        if (bad_addresses)
        {
            if (errhd[sizeof("X-Fetchmail-Warning: ")])
                strcat(errhd, "; ");
            strcat(errhd, _("SMTP listener rejected local recipient addresses: "));
            errlen = strlen(errhd);
            for (idp = msgblk.recipients; idp; idp = idp->next)
                if (idp->val.status.mark == XMIT_RCPTBAD)
                    errlen += strlen(idp->id) + 2;

            xalloca(errmsg, char *, errlen+3);
            (void) strcpy(errmsg, errhd);
            for (idp = msgblk.recipients; idp; idp = idp->next)
                if (idp->val.status.mark == XMIT_RCPTBAD)
                {
                    strcat(errmsg, idp->id);
                    if (idp->next)
                        strcat(errmsg, ", ");
                }

        }

        strcat(errmsg, "\r\n");

        /* ship out the error line */
        stuffline(ctl, errmsg);
    }

    /* issue the delimiter line */
    cp = buf;
    *cp++ = '\r';
    *cp++ = '\n';
    *cp++ = '\0';
    stuffline(ctl, buf);

    free(msgblk.headers);
    free_str_list(&msgblk.recipients);
    return(headers_ok ? PS_SUCCESS : PS_TRUNCATED);
}

static int readbody(int sock, struct query *ctl, flag forward, int len)
/* read and dispose of a message body presented on sock */
/*   ctl:               query control record */
/*   sock:              to which the server is connected */
/*   len:               length of message */
/*   forward:           TRUE to forward */
{
    int linelen;
    unsigned char buf[MSGBUFSIZE+4];
    unsigned char *inbufp = buf;
    flag issoftline = FALSE;

    /* pass through the text lines */
    while (protocol->delimited || len > 0)
    {
        set_timeout(mytimeout);
        if ((linelen = SockRead(sock, inbufp, sizeof(buf)-4-(inbufp-buf)))==-1)
        {
            set_timeout(0);
            release_sink(ctl);
            return(PS_SOCKET);
        }
        set_timeout(0);

        /* write the message size dots */
        if (linelen > 0)
        {
            sizeticker += linelen;
            while (sizeticker >= SIZETICKER)
            {
                if (!run.use_syslog && outlevel > O_SILENT)
                    error_build(".");
                sizeticker -= SIZETICKER;
            }
        }
        len -= linelen;

        /* check for end of message */
        if (protocol->delimited && *inbufp == '.')
            if (inbufp[1] == '\r' && inbufp[2] == '\n' && inbufp[3] == '\0')
                break;
            else if (inbufp[1] == '\n' && inbufp[2] == '\0')
                break;
            else
                msglen--;       /* subtract the size of the dot escape */

        msglen += linelen;

        if (ctl->mimedecode && (ctl->mimemsg & MSG_NEEDS_DECODE)) {
            issoftline = UnMimeBodyline(&inbufp, (protocol->delimited && issoftline));
            if (issoftline && (sizeof(buf)-1-(inbufp-buf) < 200))
            {
                /*
                 * Soft linebreak, but less than 200 bytes left in
                 * input buffer. Rather than doing a buffer overrun,
                 * ignore the soft linebreak, NL-terminate data and
                 * deliver what we have now.
                 * (Who writes lines longer than 2K anyway?)
                 */
                *inbufp = '\n'; *(inbufp+1) = '\0';
                issoftline = 0;
            }
        }

        /* ship out the text line */
        if (forward && (!issoftline))
        {
            int n;
            inbufp = buf;

            /* guard against very long lines */
            buf[MSGBUFSIZE+1] = '\r';
            buf[MSGBUFSIZE+2] = '\n';
            buf[MSGBUFSIZE+3] = '\0';

            n = stuffline(ctl, buf);

            if (n < 0)
            {
                error(0, errno, _("writing message text"));
                release_sink(ctl);
                return(PS_IOERR);
            }
            else if (outlevel >= O_VERBOSE)
                fputc('*', stderr);
        }
    }

    return(PS_SUCCESS);
}

#ifdef KERBEROS_V4
int
kerberos_auth (socket, canonical) 
/* authenticate to the server host using Kerberos V4 */
int socket;             /* socket to server host */
#ifdef __FreeBSD__
char *canonical;        /* server name */
#else
const char *canonical;  /* server name */
#endif
{
    char * host_primary;
    KTEXT ticket;
    MSG_DAT msg_data;
    CREDENTIALS cred;
    Key_schedule schedule;
    int rem;
  
    xalloca(ticket, KTEXT, sizeof (KTEXT_ST));
    rem = (krb_sendauth (0L, socket, ticket, "pop",
                         canonical,
                         ((char *) (krb_realmofhost (canonical))),
                         ((unsigned long) 0),
                         (&msg_data),
                         (&cred),
                         (schedule),
                         ((struct sockaddr_in *) 0),
                         ((struct sockaddr_in *) 0),
                         "KPOPV0.1"));
    if (rem != KSUCCESS)
    {
        error(0, -1, _("kerberos error %s"), (krb_get_err_text (rem)));
        return (PS_AUTHFAIL);
    }
    return (0);
}
#endif /* KERBEROS_V4 */

#ifdef KERBEROS_V5
static int kerberos5_auth(socket, canonical)
/* authenticate to the server host using Kerberos V5 */
int socket;             /* socket to server host */
const char *canonical;  /* server name */
{
    krb5_error_code retval;
    krb5_context context;
    krb5_ccache ccdef;
    krb5_principal client = NULL, server = NULL;
    krb5_error *err_ret = NULL;

    krb5_auth_context auth_context = NULL;

    krb5_init_context(&context);
    krb5_init_ets(context);
    krb5_auth_con_init(context, &auth_context);

    if (retval = krb5_cc_default(context, &ccdef)) {
        error(0, 0, "krb5_cc_default: %s", error_message(retval));
        return(PS_ERROR);
    }

    if (retval = krb5_cc_get_principal(context, ccdef, &client)) {
        error(0, 0, "krb5_cc_get_principal: %s", error_message(retval));
        return(PS_ERROR);
    }

    if (retval = krb5_sname_to_principal(context, canonical, "pop",
           KRB5_NT_UNKNOWN,
           &server)) {
        error(0, 0, "krb5_sname_to_principal: %s", error_message(retval));
        return(PS_ERROR);
    }

    retval = krb5_sendauth(context, &auth_context, (krb5_pointer) &socket,
         "KPOPV1.0", client, server,
         AP_OPTS_MUTUAL_REQUIRED,
         NULL,  /* no data to checksum */
         0,   /* no creds, use ccache instead */
         ccdef,
         &err_ret, 0,

         NULL); /* don't need reply */

    krb5_free_principal(context, server);
    krb5_free_principal(context, client);
    krb5_auth_con_free(context, auth_context);

    if (retval) {
      if (err_ret && err_ret->text.length) {
          error(0, 0, _("krb5_sendauth: %s [server says '%*s'] "),
            error_message(retval),
            err_ret->text.length,
            err_ret->text.data);
          krb5_free_error(context, err_ret);
      } else
          error(0, 0, "krb5_sendauth: %s", error_message(retval));
      return(PS_ERROR);
    }

    return 0;
}
#endif /* KERBEROS_V5 */

static void clean_skipped_list(struct idlist **skipped_list)
/* struct "idlist" contains no "prev" ptr; we must remove unused items first */
{
    struct idlist *current=NULL, *prev=NULL, *tmp=NULL, *head=NULL;
    prev = current = head = *skipped_list;

    if (!head)
        return;
    do
    {
        /* if item has no reference, remove it */
        if (current && current->val.status.mark == 0)
        {
            if (current == head) /* remove first item (head) */
            {
                head = current->next;
                if (current->id) free(current->id);
                free(current);
                prev = current = head;
            }
            else /* remove middle/last item */
            {
                tmp = current->next;
                prev->next = tmp;
                if (current->id) free(current->id);
                free(current);
                current = tmp;
            }
        }
        else /* skip this item */
        {
            prev = current;
            current = current->next;
        }
    } while(current);

    *skipped_list = head;
}

static void send_size_warnings(struct query *ctl)
/* send warning mail with skipped msg; reset msg count when user notified */
{
    int size, nbr;
    int msg_to_send = FALSE;
    struct idlist *head=NULL, *current=NULL;
    int max_warning_poll_count, good, bad;
#define OVERHD  "Subject: Fetchmail oversized-messages warning.\r\n\r\nThe following oversized messages remain on the mail server:"

    head = ctl->skipped;
    if (!head)
        return;

    /* don't start a notification message unless we need to */
    for (current = head; current; current = current->next)
        if (current->val.status.num == 0 && current->val.status.mark)
            msg_to_send = TRUE;
    if (!msg_to_send)
        return;

    /*
     * There's no good way to recover if we can't send notification mail, 
     * but it's not a disaster, either, since the skipped mail will not
     * be deleted.
     */
    if (open_warning_by_mail(ctl, (struct msgblk *)NULL))
        return;
    stuff_warning(ctl, OVERHD);
 
    if (run.poll_interval == 0)
        max_warning_poll_count = 0;
    else
        max_warning_poll_count = ctl->warnings/run.poll_interval;

    /* parse list of skipped msg, adding items to the mail */
    for (current = head; current; current = current->next)
    {
        if (current->val.status.num == 0 && current->val.status.mark)
        {
            nbr = current->val.status.mark;
            size = atoi(current->id);
            stuff_warning(ctl, 
                    _("\t%d msg %d octets long skipped by fetchmail."),
                    nbr, size);
        }
        current->val.status.num++;
        current->val.status.mark = 0;

        if (current->val.status.num >= max_warning_poll_count)
            current->val.status.num = 0;
    }

    close_warning_by_mail(ctl, (struct msgblk *)NULL);
#undef OVERHD
}

int do_protocol(ctl, proto)
/* retrieve messages from server using given protocol method table */
struct query *ctl;              /* parsed options with merged-in defaults */
const struct method *proto;     /* protocol method table */
{
    int ok, js;
#ifdef HAVE_VOLATILE
    volatile int sock = -1;     /* pacifies -Wall */
#else
    int sock = -1;
#endif /* HAVE_VOLATILE */
    const char *msg;
    void (*sigsave)(int);
    struct idlist *current=NULL, *tmp=NULL;

    protocol = proto;
    ctl->server.base_protocol = protocol;

#ifndef KERBEROS_V4
    if (ctl->server.preauthenticate == A_KERBEROS_V4)
    {
        error(0, -1, _("Kerberos V4 support not linked."));
        return(PS_ERROR);
    }
#endif /* KERBEROS_V4 */

#ifndef KERBEROS_V5
    if (ctl->server.preauthenticate == A_KERBEROS_V5)
    {
        error(0, -1, _("Kerberos V5 support not linked."));
        return(PS_ERROR);
    }
#endif /* KERBEROS_V5 */

    /* lacking methods, there are some options that may fail */
    if (!proto->is_old)
    {
        /* check for unsupported options */
        if (ctl->flush) {
            error(0, 0,
                    _("Option --flush is not supported with %s"),
                    proto->name);
            return(PS_SYNTAX);
        }
        else if (ctl->fetchall) {
            error(0, 0,
                    _("Option --all is not supported with %s"),
                    proto->name);
            return(PS_SYNTAX);
        }
    }
    if (!proto->getsizes && NUM_SPECIFIED(ctl->limit))
    {
        error(0, 0,
                _("Option --limit is not supported with %s"),
                proto->name);
        return(PS_SYNTAX);
    }

    pass = 0;
    tagnum = 0;
    tag[0] = '\0';      /* nuke any tag hanging out from previous query */
    ok = 0;

    /* set up the server-nonresponse timeout */
    sigsave = signal(SIGALRM, timeout_handler);
    mytimeout = ctl->server.timeout;

    if ((js = setjmp(restart)) == 1)
    {
        if (phase == OPEN_WAIT)
            error(0, 0,
                  _("timeout after %d seconds waiting to connect to server %s."),
                  ctl->server.timeout, ctl->server.pollname);
        else if (phase == SERVER_WAIT)
            error(0, 0,
                  _("timeout after %d seconds waiting for server %s."),
                  ctl->server.timeout, ctl->server.pollname);
        else if (phase == FORWARDING_WAIT)
            error(0, 0,
                  _("timeout after %d seconds waiting for %s."),
                  ctl->server.timeout,
                  ctl->mda ? "MDA" : "SMTP");
        else if (phase == LISTENER_WAIT)
            error(0, 0,
                  _("timeout after %d seconds waiting for listener to respond."));
        else
            error(0, 0, _("timeout after %d seconds."), ctl->server.timeout);

        release_sink(ctl);
        if (ctl->smtp_socket != -1)
            close(ctl->smtp_socket);
        if (sock != -1)
            SockClose(sock);

        /*
         * If we've exceeded our threshold for consecutive timeouts, 
         * try to notify the user, then mark the connection wedged.
         */
        if (timeoutcount > MAX_TIMEOUTS 
                        && !open_warning_by_mail(ctl, (struct msgblk *)NULL))
        {
            stuff_warning(ctl,
                          _("Subject: fetchmail sees repeated timeouts\r\n"));
            stuff_warning(ctl,
                          _("Fetchmail saw more than %d timouts while attempting to get mail from %s@%s."), 
                          MAX_TIMEOUTS,
                          ctl->remotename,
                          ctl->server.truename);
            stuff_warning(ctl, 
                          _("This could mean that your mailserver is stuck, or that your SMTP listener"));
            stuff_warning(ctl, 
                          _("is wedged, or that your mailbox file on the server has been corrupted by"));
            stuff_warning(ctl, 
                          _("a server error.  You can run `fetchmail -v -v' to diagnose the problem."));
            stuff_warning(ctl,
                          _("Fetchmail won't poll this mailbox again until you restart it."));
            close_warning_by_mail(ctl, (struct msgblk *)NULL);
            ctl->wedged = TRUE;
        }

        ok = PS_ERROR;
    }
    else
    {
        char buf[POPBUFSIZE+1], *realhost;
        int len, num, count, new, bytes, deletions = 0, *msgsizes = NULL;
#if INET6
        int fetches, dispatches;
#else /* INET6 */
        int port, fetches, dispatches, oldphase;
#endif /* INET6 */
        struct idlist *idp;

        /* execute pre-initialization command, if any */
        if (ctl->preconnect && (ok = system(ctl->preconnect)))
        {
            sprintf(buf, _("pre-connection command failed with status %d"), ok);
            error(0, 0, buf);
            ok = PS_SYNTAX;
            goto closeUp;
        }

        /* open a socket to the mail server */
        oldphase = phase;
        phase = OPEN_WAIT;
        set_timeout(mytimeout);
#if !INET6
        port = ctl->server.port ? ctl->server.port : protocol->port;
#endif /* !INET6 */
        realhost = ctl->server.via ? ctl->server.via : ctl->server.pollname;
#if INET6
        if ((sock = SockOpen(realhost, 
                             ctl->server.service ? ctl->server.service : protocol->service,
                             ctl->server.netsec)) == -1, ctl->server.plugin
            )
#else /* INET6 */
        if ((sock = SockOpen(realhost, port, NULL, ctl->server.plugin)) == -1)
#endif /* INET6 */
        {
#if !INET6
            int err_no = errno;
#ifdef HAVE_RES_SEARCH
            if (err_no != 0 && h_errno != 0)
                error(0, 0, _("fetchmail: internal inconsistency"));
#endif
            /*
             * Avoid generating a bogus error every poll cycle when we're
             * in daemon mode but the connection to the outside world
             * is down.
             */
            if (err_no == EHOSTUNREACH && run.poll_interval)
                goto ehostunreach;

            error_build(_("fetchmail: %s connection to %s failed"), 
                         protocol->name, ctl->server.pollname);
#ifdef HAVE_RES_SEARCH
            if (h_errno != 0)
            {
                if (h_errno == HOST_NOT_FOUND)
                    error_complete(0, 0, _(": host is unknown"));
                else if (h_errno == NO_ADDRESS)
                    error_complete(0, 0, _(": name is valid but has no IP address"));
                else if (h_errno == NO_RECOVERY)
                    error_complete(0, 0, _(": unrecoverable name server error"));
                else if (h_errno == TRY_AGAIN)
                    error_complete(0, 0, _(": temporary name server error"));
                else
                    error_complete(0, 0, _(": unknown DNS error %d"), h_errno);
            }
            else
#endif /* HAVE_RES_SEARCH */

                error_complete(0, err_no, "");

        ehostunreach:
#endif /* INET6 */
            ok = PS_SOCKET;
            set_timeout(0);
            phase = oldphase;
            goto closeUp;
        }
        set_timeout(0);
        phase = oldphase;

#ifdef KERBEROS_V4
        if (ctl->server.preauthenticate == A_KERBEROS_V4)
        {
            set_timeout(mytimeout);
            ok = kerberos_auth(sock, ctl->server.truename);
            set_timeout(0);
            if (ok != 0)
                goto cleanUp;
        }
#endif /* KERBEROS_V4 */

#ifdef KERBEROS_V5
        if (ctl->server.preauthenticate == A_KERBEROS_V5)
        {
            set_timeout(mytimeout);
            ok = kerberos5_auth(sock, ctl->server.truename);
            set_timeout(0);
            if (ok != 0)
                goto cleanUp;
        }
#endif /* KERBEROS_V5 */

        /* accept greeting message from mail server */
        ok = (protocol->parse_response)(sock, buf);
        if (ok != 0)
            goto cleanUp;

        /* try to get authorized to fetch mail */
        if (protocol->getauth)
        {
            if (protocol->password_canonify)
                (protocol->password_canonify)(shroud, ctl->password);
            else
                strcpy(shroud, ctl->password);

            ok = (protocol->getauth)(sock, ctl, buf);
            if (ok != 0)
            {
                if (ok == PS_LOCKBUSY)
                    error(0, -1, _("Lock-busy error on %s@%s"),
                          ctl->remotename,
                          ctl->server.truename);
                else
                {
                    if (ok == PS_ERROR)
                        ok = PS_AUTHFAIL;
                    error(0, -1, _("Authorization failure on %s@%s"), 
                          ctl->remotename,
                          ctl->server.truename);

                    /*
                     * If we're running in background, try to mail the
                     * calling user a heads-up about the authentication 
                     * failure the first time it happens.
                     */
                    if (run.poll_interval
                        && !ctl->wedged 
                        && !open_warning_by_mail(ctl, (struct msgblk *)NULL))
                    {
                        stuff_warning(ctl,
                               _("Subject: fetchmail authentication failed\r\n"));
                        stuff_warning(ctl,
                                _("Fetchmail could not get mail from %s@%s."), 
                                ctl->remotename,
                                ctl->server.truename);
                        stuff_warning(ctl, 
                               _("The attempt to get authorization failed."));
                        stuff_warning(ctl, 
                               _("This probably means your password is invalid."));
                        close_warning_by_mail(ctl, (struct msgblk *)NULL);
                        ctl->wedged = TRUE;
                    }
                }
                goto cleanUp;
            }
        }

        ctl->errcount = fetches = 0;

        /* now iterate over each folder selected */
        for (idp = ctl->mailboxes; idp; idp = idp->next)
        {
            pass = 0;
            do {
                dispatches = 0;
                ++pass;

                if (outlevel >= O_DEBUG)
                    if (idp->id)
                        error(0, 0, _("selecting or re-polling folder %s"), idp->id);
                    else
                        error(0, 0, _("selecting or re-polling default folder"));

                /* compute # of messages and number of new messages waiting */
                ok = (protocol->getrange)(sock, ctl, idp->id, &count, &new, &bytes);
                if (ok != 0)
                    goto cleanUp;

                /* 
                 * We need the size of each message before it's
                 * loaded in order to pass via the ESMTP SIZE
                 * option.  If the protocol has a getsizes method,
                 * we presume this means it doesn't get reliable
                 * sizes from message fetch responses.
                 */
                if (count > 0 && proto->getsizes)
                {
                    int i;

                    xalloca(msgsizes, int *, sizeof(int) * count);
                    for (i = 0; i < count; i++)
                        msgsizes[i] = -1;

                    ok = (proto->getsizes)(sock, count, msgsizes);
                    if (ok != 0)
                        goto cleanUp;

                    if (bytes == -1)
                    {
                        bytes = 0;
                        for (i = 0; i < count; i++)
                            bytes += msgsizes[i];
                    }
                }

                /* show user how many messages we downloaded */
                if (idp->id)
                    (void) sprintf(buf, _("%s at %s (folder %s)"),
                                   ctl->remotename, ctl->server.truename, idp->id);
                else
                    (void) sprintf(buf, _("%s at %s"),
                                   ctl->remotename, ctl->server.truename);
                if (outlevel > O_SILENT)
                    if (count == -1)            /* only used for ETRN */
                        error(0, 0, _("Polling %s"), ctl->server.truename);
                    else if (count != 0)
                    {
                        if (new != -1 && (count - new) > 0)
                            error_build(_("%d %s (%d seen) for %s"),
                                  count, count > 1 ? _("messages") :
                                                     _("message"),
                                  count-new, buf);
                        else
                            error_build(_("%d %s for %s"), 
                                  count, count > 1 ? _("messages") :
                                                     _("message"), buf);
                        if (bytes == -1)
                            error_complete(0, 0, ".");
                        else
                            error_complete(0, 0, _(" (%d octets)."), bytes);
                    }
                    else
                    {
                        /* these are pointless in normal daemon mode */
                        if (pass == 1 && (run.poll_interval == 0 || outlevel >= O_VERBOSE))
                            error(0, 0, _("No mail for %s"), buf); 
                    }

                /* very important, this is where we leave the do loop */ 
                if (count == 0)
                    break;

                if (check_only)
                {
                    if (new == -1 || ctl->fetchall)
                        new = count;
                    ok = ((new > 0) ? PS_SUCCESS : PS_NOMAIL);
                    goto cleanUp;
                }
                else if (count > 0)
                {    
                    flag        force_retrieval;

                    /*
                     * What forces this code is that in POP2 and
                     * IMAP2bis you can't fetch a message without
                     * having it marked `seen'.  In POP3 and IMAP4, on the
                     * other hand, you can (peek_capable is set by 
                     * each driver module to convey this; it's not a
                     * method constant because of the difference between
                     * IMAP2bis and IMAP4, and because POP3 doesn't  peek
                     * if fetchall is on).
                     *
                     * The result of being unable to peek is that if there's
                     * any kind of transient error (DNS lookup failure, or
                     * sendmail refusing delivery due to process-table limits)
                     * the message will be marked "seen" on the server without
                     * having been delivered.  This is not a big problem if
                     * fetchmail is running in foreground, because the user
                     * will see a "skipped" message when it next runs and get
                     * clued in.
                     *
                     * But in daemon mode this leads to the message
                     * being silently ignored forever.  This is not
                     * acceptable.
                     *
                     * We compensate for this by checking the error
                     * count from the previous pass and forcing all
                     * messages to be considered new if it's nonzero.
                     */
                    force_retrieval = !peek_capable && (ctl->errcount > 0);

                    /* read, forward, and delete messages */
                    for (num = 1; num <= count; num++)
                    {
                        flag toolarge = NUM_NONZERO(ctl->limit)
                            && msgsizes && (msgsizes[num-1] > ctl->limit);
                        flag oldmsg = (!new) || (protocol->is_old && (protocol->is_old)(sock,ctl,num));
                        flag fetch_it = !toolarge 
                            && (ctl->fetchall || force_retrieval || !oldmsg);
                        flag suppress_delete = FALSE;
                        flag suppress_forward = FALSE;
                        flag suppress_readbody = FALSE;
                        flag retained = FALSE;

                        /*
                         * This check copes with Post Office/NT's
                         * annoying habit of randomly prepending bogus
                         * LIST items of length -1.  Patrick Audley
                         * <paudley@pobox.com> tells us: LIST shows a
                         * size of -1, RETR and TOP return "-ERR
                         * System error - couldn't open message", and
                         * DELE succeeds but doesn't actually delete
                         * the message.
                         */
                        if (msgsizes && msgsizes[num-1] == -1)
                        {
                            if (outlevel >= O_VERBOSE)
                                error(0, 0, 
                                      _("Skipping message %d, length -1"),
                                      num - 1);
                            continue;
                        }

                        /* we may want to reject this message if it's old */
                        if (!fetch_it)
                        {
                            if (outlevel > O_SILENT)
                            {
                                error_build(_("skipping message %d"), num);
                                if (toolarge && !check_only) 
                                {
                                    char size[32];
                                    int cnt;

                                    /* convert sz to string */
                                    sprintf(size, "%d", msgsizes[num-1]);

                                    /* build a list of skipped messages
                                     * val.id = size of msg (string cnvt)
                                     * val.status.num = warning_poll_count
                                     * val.status.mask = nbr of msg this size
                                     */

                                    current = ctl->skipped;

                                    /* initialise warning_poll_count to the
                                     * current value so that all new msg will
                                     * be included in the next mail
                                     */
                                    cnt = current? current->val.status.num : 0;

                                    /* if entry exists, increment the count */
                                    if (current && 
                                        str_in_list(&current, size, FALSE))
                                    {
                                        for ( ; current; 
                                                current = current->next)
                                        {
                                            if (strcmp(current->id, size) == 0)
                                            {
                                                current->val.status.mark++;
                                                break;
                                            }
                                        }
                                    }
                                    /* otherwise, create a new entry */
                                    /* initialise with current poll count */
                                    else
                                    {
                                        tmp = save_str(&ctl->skipped, size, 1);
                                        tmp->val.status.num = cnt;
                                    }

                                    error_build(_(" (oversized, %d octets)"),
                                                msgsizes[num-1]);
                                }
                            }
                        }
                        else
                        {
                            flag wholesize = !protocol->fetch_body;

                            /* request a message */
                            ok = (protocol->fetch_headers)(sock,ctl,num, &len);
                            if (ok != 0)
                                goto cleanUp;

                            /* -1 means we didn't see a size in the response */
                            if (len == -1 && msgsizes)
                            {
                                len = msgsizes[num - 1];
                                wholesize = TRUE;
                            }

                            if (outlevel > O_SILENT)
                            {
                                error_build(_("reading message %d of %d"),
                                            num,count);

                                if (len > 0)
                                    error_build(_(" (%d %soctets)"),
                                        len, wholesize ? "" : _("header "));
                                if (outlevel >= O_VERBOSE)
                                    error_complete(0, 0, "");
                                else
                                    error_build(" ");
                            }

                            /* 
                             * Read the message headers and ship them to the
                             * output sink.  
                             */
                            ok = readheaders(sock, len, msgsizes[num-1],
                                             ctl, num);
                            if (ok == PS_RETAINED)
                                suppress_forward = retained = TRUE;
                            else if (ok == PS_TRANSIENT)
                                suppress_delete = suppress_forward = TRUE;
                            else if (ok == PS_REFUSED)
                                suppress_forward = TRUE;
                            else if (ok == PS_TRUNCATED)
                                suppress_readbody = TRUE;
                            else if (ok)
                                goto cleanUp;

                            /* 
                             * If we're using IMAP4 or something else that
                             * can fetch headers separately from bodies,
                             * it's time to request the body now.  This
                             * fetch may be skipped if we got an anti-spam
                             * or other PS_REFUSED error response during
                             * readheaders.
                             */
                            if (protocol->fetch_body && !suppress_readbody) 
                            {
                                if (outlevel >= O_VERBOSE)
                                    fputc('\n', stderr);

                                if ((ok = (protocol->trail)(sock, ctl, num)))
                                    goto cleanUp;
                                len = 0;
                                if (!suppress_forward)
                                {
                                    if ((ok=(protocol->fetch_body)(sock,ctl,num,&len)))
                                        goto cleanUp;
                                    if (outlevel > O_SILENT && !wholesize)
                                        error_build(_(" (%d body octets) "), len);
                                }
                            }

                            /* process the body now */
                            if (len > 0)
                            {
                                if (suppress_readbody)
                                {
                                  /* When readheaders returns PS_TRUNCATED,
                                     the body (which has no content
                                     has already been read by readheaders,
                                     so we say readbody returned PS_SUCCESS */
                                  ok = PS_SUCCESS;
                                }
                                else
                                {
                                  ok = readbody(sock,
                                                ctl,
                                                !suppress_forward,
                                                len);
                                }
                                if (ok == PS_TRANSIENT)
                                    suppress_delete = suppress_forward = TRUE;
                                else if (ok)
                                    goto cleanUp;

                                /* tell server we got it OK and resynchronize */
                                if (protocol->trail)
                                {
                                    if (outlevel >= O_VERBOSE)
                                        fputc('\n', stderr);

                                    ok = (protocol->trail)(sock, ctl, num);
                                    if (ok != 0)
                                        goto cleanUp;
                                }
                            }

                            /* count # messages forwarded on this pass */
                            if (!suppress_forward)
                                dispatches++;

                            /*
                             * Check to see if the numbers matched?
                             *
                             * Yes, some servers foo this up horribly.
                             * All IMAP servers seem to get it right, and
                             * so does Eudora QPOP at least in 2.xx
                             * versions.
                             *
                             * Microsoft Exchange gets it completely
                             * wrong, reporting compressed rather than
                             * actual sizes (so the actual length of
                             * message is longer than the reported size).
                             * Another fine example of Microsoft brain death!
                             *
                             * Some older POP servers, like the old UCB
                             * POP server and the pre-QPOP QUALCOMM
                             * versions, report a longer size in the LIST
                             * response than actually gets shipped up.
                             * It's unclear what is going on here, as the
                             * QUALCOMM server (at least) seems to be
                             * reporting the on-disk size correctly.
                             */
                            if (msgsizes && msglen != msgsizes[num-1])
                            {
                                if (outlevel >= O_DEBUG)
                                    error(0, 0,
                                          _("message %d was not the expected length (%d actual != %d expected)"),
                                          num, msglen, msgsizes[num-1]);
                            }

                            /* end-of-message processing starts here */
                            if (!close_sink(ctl, &msgblk, !suppress_forward))
                            {
                                ctl->errcount++;
                                suppress_delete = TRUE;
                            }
                            fetches++;
                        }

                        /*
                         * At this point in flow of control, either
                         * we've bombed on a protocol error or had
                         * delivery refused by the SMTP server
                         * (unlikely -- I've never seen it) or we've
                         * seen `accepted for delivery' and the
                         * message is shipped.  It's safe to mark the
                         * message seen and delete it on the server
                         * now.
                         */

                        /* tell the UID code we've seen this */
                        if (ctl->newsaved)
                        {
                            struct idlist       *sdp;

                            for (sdp = ctl->newsaved; sdp; sdp = sdp->next)
                                if (sdp->val.status.num == num)
                                    sdp->val.status.mark = UID_SEEN;
                        }

                        /* maybe we delete this message now? */
                        if (retained)
                        {
                            if (outlevel > O_SILENT) 
                                error_complete(0, 0, _(" retained"));
                        }
                        else if (protocol->delete
                                 && !suppress_delete
                                 && (fetch_it ? !ctl->keep : ctl->flush))
                        {
                            deletions++;
                            if (outlevel > O_SILENT) 
                                error_complete(0, 0, _(" flushed"));
                            ok = (protocol->delete)(sock, ctl, num);
                            if (ok != 0)
                                goto cleanUp;
#ifdef POP3_ENABLE
                            delete_str(&ctl->newsaved, num);
#endif /* POP3_ENABLE */
                        }
                        else if (outlevel > O_SILENT) 
                            error_complete(0, 0, _(" not flushed"));

                        /* perhaps this as many as we're ready to handle */
                        if (NUM_NONZERO(ctl->fetchlimit)
                                        && ctl->fetchlimit <= fetches)
                        {
                            error(0, 0, _("fetchlimit reached; %d messages left on server"),
                                  count - fetches);
                            goto no_error;
                        }
                    }

                    if (!check_only && ctl->skipped)
                    {
                        clean_skipped_list(&ctl->skipped);
                        send_size_warnings(ctl);
                    }
                }
            } while
                  /*
                   * Only re-poll if we had some actual forwards, allowed
                   * deletions and had no errors.
                   * Otherwise it is far too easy to get into infinite loops.
                   */
                  (dispatches && protocol->retry && !ctl->keep && !ctl->errcount);
        }

   no_error:
        /* ordinary termination with no errors -- officially log out */
        ok = (protocol->logout_cmd)(sock, ctl);
        /*
         * Hmmmm...arguably this would be incorrect if we had fetches but
         * no dispatches (due to oversized messages, etc.)
         */
        if (ok == 0)
            ok = (fetches > 0) ? PS_SUCCESS : PS_NOMAIL;
        SockClose(sock);
        goto closeUp;

    cleanUp:
        /* we only get here on error */
        if (ok != 0 && ok != PS_SOCKET)
            (protocol->logout_cmd)(sock, ctl);
        SockClose(sock);
    }

    msg = (const char *)NULL;   /* sacrifice to -Wall */
    switch (ok)
    {
    case PS_SOCKET:
        msg = _("socket");
        break;
    case PS_AUTHFAIL:
        msg = _("authorization");
        break;
    case PS_SYNTAX:
        msg = _("missing or bad RFC822 header");
        break;
    case PS_IOERR:
        msg = _("MDA");
        break;
    case PS_ERROR:
        msg = _("client/server synchronization");
        break;
    case PS_PROTOCOL:
        msg = _("client/server protocol");
        break;
    case PS_LOCKBUSY:
        msg = _("lock busy on server");
        break;
    case PS_SMTP:
        msg = _("SMTP transaction");
        break;
    case PS_DNS:
        msg = _("DNS lookup");
        break;
    case PS_UNDEFINED:
        error(0, 0, _("undefined"));
        break;
    }
    if (ok==PS_SOCKET || ok==PS_AUTHFAIL || ok==PS_SYNTAX 
                || ok==PS_IOERR || ok==PS_ERROR || ok==PS_PROTOCOL 
                || ok==PS_LOCKBUSY || ok==PS_SMTP)
        error(0,-1, _("%s error while fetching from %s"), msg, ctl->server.pollname);

closeUp:
    /* execute post-initialization command, if any */
    if (ctl->postconnect && (ok = system(ctl->postconnect)))
    {
        char buf[80];

        sprintf(buf, _("post-connection command failed with status %d"), ok);
        error(0, 0, buf);
        if (ok == PS_SUCCESS)
            ok = PS_SYNTAX;
    }

    signal(SIGALRM, sigsave);
    return(ok);
}

#if defined(HAVE_STDARG_H)
void gen_send(int sock, const char *fmt, ... )
#else
void gen_send(sock, fmt, va_alist)
int sock;               /* socket to which server is connected */
const char *fmt;        /* printf-style format */
va_dcl
#endif
/* assemble command in printf(3) style and send to the server */
{
    char buf [MSGBUFSIZE+1];
    va_list ap;

    if (protocol->tagged)
        (void) sprintf(buf, "%s ", GENSYM);
    else
        buf[0] = '\0';

#if defined(HAVE_STDARG_H)
    va_start(ap, fmt) ;
#else
    va_start(ap);
#endif
#ifdef HAVE_VSNPRINTF
    vsnprintf(buf + strlen(buf), sizeof(buf), fmt, ap);
#else
    vsprintf(buf + strlen(buf), fmt, ap);
#endif
    va_end(ap);

    strcat(buf, "\r\n");
    SockWrite(sock, buf, strlen(buf));

    if (outlevel >= O_MONITOR)
    {
        char *cp;

        if (shroud && shroud[0] && (cp = strstr(buf, shroud)))
        {
            char        *sp;

            sp = cp + strlen(shroud);
            *cp++ = '*';
            while (*sp)
                *cp++ = *sp++;
            *cp = '\0';
        }
        buf[strlen(buf)-2] = '\0';
        error(0, 0, "%s> %s", protocol->name, buf);
    }
}

int gen_recv(sock, buf, size)
/* get one line of input from the server */
int sock;       /* socket to which server is connected */
char *buf;      /* buffer to receive input */
int size;       /* length of buffer */
{
    int oldphase = phase;       /* we don't have to be re-entrant */

    phase = SERVER_WAIT;
    set_timeout(mytimeout);
    if (SockRead(sock, buf, size) == -1)
    {
        set_timeout(0);
        phase = oldphase;
        return(PS_SOCKET);
    }
    else
    {
        set_timeout(0);
        if (buf[strlen(buf)-1] == '\n')
            buf[strlen(buf)-1] = '\0';
        if (buf[strlen(buf)-1] == '\r')
            buf[strlen(buf)-1] = '\0';
        if (outlevel >= O_MONITOR)
            error(0, 0, "%s< %s", protocol->name, buf);
        phase = oldphase;
        return(PS_SUCCESS);
    }
}

#if defined(HAVE_STDARG_H)
int gen_transact(int sock, const char *fmt, ... )
#else
int gen_transact(int sock, fmt, va_alist)
int sock;               /* socket to which server is connected */
const char *fmt;        /* printf-style format */
va_dcl
#endif
/* assemble command in printf(3) style, send to server, accept a response */
{
    int ok;
    char buf [MSGBUFSIZE+1];
    va_list ap;
    int oldphase = phase;       /* we don't have to be re-entrant */

    phase = SERVER_WAIT;

    if (protocol->tagged)
        (void) sprintf(buf, "%s ", GENSYM);
    else
        buf[0] = '\0';

#if defined(HAVE_STDARG_H)
    va_start(ap, fmt) ;
#else
    va_start(ap);
#endif
#ifdef HAVE_VSNPRINTF
    vsnprintf(buf + strlen(buf), sizeof(buf), fmt, ap);
#else
    vsprintf(buf + strlen(buf), fmt, ap);
#endif
    va_end(ap);

    strcat(buf, "\r\n");
    SockWrite(sock, buf, strlen(buf));

    if (outlevel >= O_MONITOR)
    {
        char *cp;

        if (shroud && shroud[0] && (cp = strstr(buf, shroud)))
        {
            char        *sp;

            sp = cp + strlen(shroud);
            *cp++ = '*';
            while (*sp)
                *cp++ = *sp++;
            *cp = '\0';
        }
        buf[strlen(buf)-1] = '\0';
        error(0, 0, "%s> %s", protocol->name, buf);
    }

    /* we presume this does its own response echoing */
    ok = (protocol->parse_response)(sock, buf);

    phase = oldphase;
    return(ok);
}

/* driver.c ends here */