Fix for core-dump bug.

[~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_ALLOCA_H)
#include <alloca.h>
#else
#ifdef _AIX
 #pragma alloca
#endif
#endif
#if defined(HAVE_SYS_ITIMER_H)
#include <sys/itimer.h>
#endif
#include  <sys/time.h>
#include  <signal.h>

#ifndef HAVE_STRFTIME /* For ctime prototype */
#include  <sys/types.h>
#include  <time.h>
#endif

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

#ifdef KERBEROS_V4
#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(__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__) */
#include <netinet/in.h>
#include <netdb.h>
#endif /* KERBEROS_V4 */
#include  "fetchmail.h"
#include  "socket.h"
#include  "smtp.h"

/* BSD portability hack...I know, this is an ugly place to put it */
#if !defined(SIGCHLD) && defined(SIGCLD)
#define SIGCHLD SIGCLD
#endif

#if INET6
#define SMTP_PORT       "smtp"  /* standard SMTP service port */
#else /* INET6 */
#define SMTP_PORT       25      /* standard SMTP service port */
#endif /* INET6 */

#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? */

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;    /* string to shroud in debug output, if  non-NULL */
static int mytimeout;   /* value of nonreponse timeout */
static int msglen;      /* actual message length */

/* use these to track what was happening when the nonresponse timer fired */
#define GENERAL_WAIT    0
#define SERVER_WAIT     1
#define FORWARDING_WAIT 2
static phase;

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

    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);
}

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

#define XMIT_ACCEPT             1
#define XMIT_REJECT             2
#define XMIT_ANTISPAM           3       
static int accept_count, reject_count;

#define MX_RETRIES      3

static int is_host_alias(const char *name, struct query *ctl)
/* determine whether name is a DNS alias of the hostname */
{
    struct hostent      *he;
    struct mxentry      *mxp, *mxrecords;

    struct hostdata *lead_server = 
        ctl->server.lead_server ? ctl->server.lead_server : &ctl->server;

    /*
     * The first two checks are optimizations that will catch a good
     * many cases.
     *
     * (1) check against the `true name' deduced from the poll label
     * and the via option (if present) at the beginning of the poll cycle.  
     * Odds are good this will either be the mailserver's FQDN or a suffix of
     * it with the mailserver's domain's default host name omitted.
     *
     * (2) Then check the rest of the `also known as'
     * cache accumulated by previous DNS checks.  This cache is primed
     * by the aka list option.
     *
     * Any of these on a mail address is definitive.  Only if the
     * name doesn't match any is it time to call the bind library.
     * If this happens odds are good we're looking at an MX name.
     */
    if (strcasecmp(lead_server->truename, name) == 0)
        return(TRUE);
    else if (str_in_list(&lead_server->akalist, name))
        return(TRUE);
    else if (!ctl->server.dns)
        return(FALSE);

#ifndef HAVE_RES_SEARCH
    return(FALSE);
#else
    /*
     * The only code that calls the BIND library is here and in the
     * start-of-query probe with gethostbyname(3).
     *
     * We know DNS service was up at the beginning of this poll cycle.
     * If it's down, our nameserver has crashed.  We don't want to try
     * delivering the current message or anything else from this
     * mailbox until it's back up.
     */
    else if ((he = gethostbyname(name)) != (struct hostent *)NULL)
    {
        if (strcasecmp(ctl->server.truename, he->h_name) == 0)
            goto match;
        else
            return(FALSE);
    }
    else
        switch (h_errno)
        {
        case HOST_NOT_FOUND:    /* specified host is unknown */
        case NO_ADDRESS:        /* valid, but does not have an IP address */
            break;

        case NO_RECOVERY:       /* non-recoverable name server error */
        case TRY_AGAIN:         /* temporary error on authoritative server */
        default:
            if (outlevel != O_SILENT)
                putchar('\n');  /* terminate the progress message */
            error(0, 0,
                "nameserver failure while looking for `%s' during poll of %s.",
                name, ctl->server.pollname);
            ctl->errcount++;
            break;
        }

    /*
     * We're only here if DNS was OK but the gethostbyname() failed
     * with a HOST_NOT_FOUND or NO_ADDRESS error.
     * Search for a name match on MX records pointing to the server.
     */
    h_errno = 0;
    if ((mxrecords = getmxrecords(name)) == (struct mxentry *)NULL)
    {
        switch (h_errno)
        {
        case HOST_NOT_FOUND:    /* specified host is unknown */
        case NO_ADDRESS:        /* valid, but does not have an IP address */
            return(FALSE);
            break;

        case NO_RECOVERY:       /* non-recoverable name server error */
        case TRY_AGAIN:         /* temporary error on authoritative server */
        default:
            error(0, -1,
                "nameserver failure while looking for `%s' during poll of %s.",
                name, ctl->server.pollname);
            ctl->errcount++;
            break;
        }
    }
    else
    {
        for (mxp = mxrecords; mxp->name; mxp++)
            if (strcasecmp(ctl->server.truename, mxp->name) == 0)
                goto match;
        return(FALSE);
    match:;
    }

    /* add this name to relevant server's `also known as' list */
    save_str(&lead_server->akalist, -1, name);
    return(TRUE);
#endif /* HAVE_RES_SEARCH */
}

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

    if (lname != (char *)NULL)
    {
        /* 
         * If the name of the user begins with a 
         * qmail virtual domain prefix, remove
         * the prefix
         */
        if (ctl->server.qvirtual)
        {
           sl=strlen(ctl->server.qvirtual);
           if (!strncasecmp(lname,ctl->server.qvirtual,sl)) off=sl; 
        }
        if (outlevel == O_VERBOSE)
            error(0, 0, "mapped %s to local %s", name, lname+off);
        save_str(xmit_names, XMIT_ACCEPT, lname+off);
        accept_count++;
    }
}

void find_server_names(hdr, ctl, xmit_names)
/* parse names out of a RFC822 header into an ID list */
const char *hdr;                /* RFC822 header in question */
struct query *ctl;              /* list of permissible aliases */
struct idlist **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 ((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_VERBOSE)
                            error(0, 0, "passed through %s matching %s", 
                                  cp, idp->id);
                        save_str(xmit_names, XMIT_ACCEPT, cp);
                        accept_count++;
                        break;
                    }
                }
                /* if we matched a local domain, idp != NULL */
                if (idp) continue;

                /*
                 * 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, XMIT_REJECT, cp);
                    reject_count++;
                    continue;
                }
                atsign[0] = '\0';
            }

            map_name(cp, ctl, xmit_names);
        }
    }
}

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 wich 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 *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 ((ok = strstr(bufp, "by ")) && isspace(ok[-1]))
    {
        char    *sp, *tp;

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

        /*
         * 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) &&
            (ok = strstr(sp, "for ")) && 
            isspace(ok[-1]))
        {
            tp = rbuf;
            sp = ok + 4;
            *tp++ = ':';        /* Here is the hack.  This is to be friend */
            *tp++ = ' ';        /* with nxtaddr()... */
            if (*sp == '<')
                sp++;
            while (*sp == '@')          /* skip routes */
                while (*sp && *sp++ != ':')
                    continue;
            while (*sp && *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)
        return(NULL);
    else
    {
        if (outlevel == O_VERBOSE) {
            char *lf = rbuf + strlen(rbuf)-1;
            *lf = '\0';
            error(0, 0, "found Received address `%s'", rbuf+2);
            *lf = '\n';
        }
        return(rbuf);
    }
}

static int smtp_open(struct query *ctl)
/* try to open a socket to the appropriate SMTP server for this query */ 
{
    /* maybe it's time to close the socket in order to force delivery */
    if (NUM_NONZERO(ctl->batchlimit) && (ctl->smtp_socket != -1) && batchcount++ == ctl->batchlimit)
    {
        close(ctl->smtp_socket);
        ctl->smtp_socket = -1;
        batchcount = 0;
    }

    /* if no socket to any SMTP host is already set up, try to open one */
    if (ctl->smtp_socket == -1) 
    {
        /* 
         * RFC 1123 requires that the domain name in HELO address is a
         * "valid principal domain name" for the client host. If we're
         * running in invisible mode, violate this with malice
         * aforethought in order to make the Received headers and
         * logging look right.
         *
         * In fact this code relies on the RFC1123 requirement that the
         * SMTP listener must accept messages even if verification of the
         * HELO name fails (RFC1123 section 5.2.5, paragraph 2).
         *
         * How we compute the true mailhost name to pass to the
         * listener doesn't affect behavior on RFC1123- violating
         * listener that check for name match; we're going to lose
         * on those anyway because we can never give them a name
         * that matches the local machine fetchmail is running on.
         * What it will affect is the listener's logging.
         */
        struct idlist   *idp;
        char *id_me = use_invisible ? ctl->server.truename : fetchmailhost;

        errno = 0;

        /*
         * Run down the SMTP hunt list looking for a server that's up.
         * Use both explicit hunt entries (value TRUE) and implicit 
         * (default) ones (value FALSE).
         */
        for (idp = ctl->smtphunt; idp; idp = idp->next)
        {
            char        *cp, *parsed_host = alloca(strlen(idp->id) + 1);
#ifdef INET6 
            char        *portnum = SMTP_PORT;
#else
            int         portnum = SMTP_PORT;
#endif /* INET6 */

            ctl->smtphost = idp->id;  /* remember last host tried. */

            strcpy(parsed_host, idp->id);
            if ((cp = strrchr(parsed_host, '/')))
            {
                *cp++ = 0;
#ifdef INET6 
                portnum = cp;
#else
                portnum = atoi(cp);
#endif /* INET6 */
            }

            if ((ctl->smtp_socket = SockOpen(parsed_host,portnum,NULL)) == -1)
                continue;

            /* first, probe for ESMTP */
            if (SMTP_ok(ctl->smtp_socket) == SM_OK &&
                    SMTP_ehlo(ctl->smtp_socket, id_me,
                          &ctl->server.esmtp_options) == SM_OK)
               break;  /* success */

            /*
             * RFC 1869 warns that some listeners hang up on a failed EHLO,
             * so it's safest not to assume the socket will still be good.
             */
            close(ctl->smtp_socket);
            ctl->smtp_socket = -1;

            /* if opening for ESMTP failed, try SMTP */
            if ((ctl->smtp_socket = SockOpen(parsed_host,portnum,NULL)) == -1)
                continue;

            if (SMTP_ok(ctl->smtp_socket) == SM_OK && 
                    SMTP_helo(ctl->smtp_socket, id_me) == SM_OK)
                break;  /* success */

            close(ctl->smtp_socket);
            ctl->smtp_socket = -1;
        }
    }

    if (outlevel >= O_VERBOSE && ctl->smtp_socket != -1)
        error(0, 0, "forwarding to %s", ctl->smtphost);

    return(ctl->smtp_socket);
}

/* these are shared by stuffline, readheaders and readbody */
static FILE *sinkfp;
static RETSIGTYPE (*sigchld)();
static int sizeticker;

static int stuffline(struct query *ctl, char *buf)
/* ship a line to the given control block's output sink (SMTP server or MDA) */
{
    int n, oldphase;
    char *last;

    /* The line may contain NUL characters. Find the last char to use
     * -- the real line termination is the sequence "\n\0".
     */
    last = buf;
    while ((last += strlen(last)) && (last[-1] != '\n'))
        last++;

    /* fix message lines that have only \n termination (for qmail) */
    if (ctl->forcecr)
    {
        if (last - 1 == buf || last[-2] != '\r')
        {
            last[-1] = '\r';
            *last++  = '\n';
            *last    = '\0';
        }
    }

    oldphase = phase;
    phase = FORWARDING_WAIT;

    /*
     * SMTP byte-stuffing.  We only do this if the protocol does *not*
     * use .<CR><LF> as EOM.  If it does, the server will already have
     * decorated any . lines it sends back up.
     */
    if (*buf == '.')
        if (protocol->delimited)        /* server has already byte-stuffed */
        {
            if (ctl->mda)
                ++buf;
            else
                /* writing to SMTP, leave the byte-stuffing in place */;
        }
        else /* if (!protocol->delimited)       -- not byte-stuffed already */
        {
            if (!ctl->mda)
                SockWrite(ctl->smtp_socket, buf, 1);    /* byte-stuff it */
            else
                /* leave it alone */;
        }

    /* we may need to strip carriage returns */
    if (ctl->stripcr)
    {
        char    *sp, *tp;

        for (sp = tp = buf; sp < last; sp++)
            if (*sp != '\r')
                *tp++ =  *sp;
        *tp = '\0';
        last = tp;
    }

    n = 0;
    if (ctl->mda)
        n = fwrite(buf, 1, last - buf, sinkfp);
    else if (ctl->smtp_socket != -1)
        n = SockWrite(ctl->smtp_socket, buf, last - buf);

    phase = oldphase;

    return(n);
}

static int readheaders(sock, fetchlen, reallen, ctl, num)
/* read message headers and ship to SMTP or MDA */
int sock;               /* to which the server is connected */
long fetchlen;          /* length of message according to fetch response */
long reallen;           /* length of message according to getsizes */
struct query *ctl;      /* query control record */
int 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];
    char                return_path[HOSTLEN + USERNAMELEN + 4]; 
    int                 from_offs, reply_to_offs, resent_from_offs;
    int                 app_from_offs, sender_offs, resent_sender_offs;
    int                 ctt_offs, env_offs;
    char                *headers, *received_for, *destaddr, *rcv, *cp;
    int                 n, linelen, oldlen, ch, remaining, skipcount;
    struct idlist       *idp, *xmit_names;
    flag                good_addresses, bad_addresses, has_nuls;
    flag                no_local_matches = FALSE;
    int                 olderrs;

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

    /* read message headers */
    headers = received_for = NULL;
    from_offs = reply_to_offs = resent_from_offs = app_from_offs = 
        sender_offs = resent_sender_offs = ctt_offs = env_offs = -1;
    oldlen = 0;
    msglen = 0;
    skipcount = 0;

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

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

            set_timeout(ctl->server.timeout);

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

            strcat(line, buf);
            if (line[0] == '\r' && line[1] == '\n')
                break;
        } while
            /* we may need to grab RFC822 continuations */
            ((ch = SockPeek(sock)) == ' ' || ch == '\t');

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

        if (linelen != strlen(line))
            has_nuls = TRUE;

        /* check for end of headers; don't save terminating line */
        if (line[0] == '\r' && line[1] == '\n')
        {
            free(line);
            break;
        }
     
        /*
         * 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(headers);
                return(PS_RETAINED);
            }

        /*
         * This code prevents fetchmail from becoming an accessory after
         * the fact to upstream sendmails with the `E' option on.  This
         * can result in an escaped Unix From_ 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 From_ line in headers.  These aren't RFC822
         * so our conscience is clear...
         */
        if (!strncasecmp(line, ">From ", 6))
        {
            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 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.
         */
        if (!strncasecmp("Return-Path:", line, 12))
        {
            strcpy(return_path, nxtaddr(line));
            if (!ctl->mda) {
                free(line);
                continue;
            }
        }

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

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

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

        else if (!strncasecmp("Content-Transfer-Encoding:", line, 26))
            ctt_offs = (line - headers);
        else if (!strncasecmp("Message-Id:", buf, 11 ))
        {
            if( ctl->server.uidl )
            {
                char id[IDLEN+1];
                /* prevent stack overflows */
                buf[IDLEN+12] = 0;
                sscanf( buf+12, "%s", id);
                if( !str_find( &ctl->newsaved, num ) )
                    save_str(&ctl->newsaved, num, id );
            }
        }

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

    /*
     * 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 (headers == (char *)NULL)
    {
#ifdef HAVE_SNPRINTF
        snprintf(buf, sizeof(buf),
#else
        sprintf(buf, 
#endif /* HAVE_SNPRINTF */
        "From: <FETCHMAIL-DAEMON@%s>\r\nTo: %s@localhost\r\nSubject: Headerless mail from %s's mailbox on %s\r\n",
                fetchmailhost, user, ctl->remotename, ctl->server.truename);
        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.
     */

    /*
     * 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 wich is the most probable real sender 
     * respectively.  *** 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:") wich is less anoying.  This is
     * true for most mailing list packages.
     */
    if( !return_path[0] ){
        char *ap = NULL;
        if (resent_sender_offs >= 0 && (ap = nxtaddr(headers + resent_sender_offs)));
        else if (sender_offs >= 0 && (ap = nxtaddr(headers + sender_offs)));
        else if (resent_from_offs >= 0 && (ap = nxtaddr(headers + resent_from_offs)));
        else if (from_offs >= 0 && (ap = nxtaddr(headers + from_offs)));
        else if (reply_to_offs >= 0 && (ap = nxtaddr(headers + reply_to_offs)));
        else if (app_from_offs >= 0 && (ap = nxtaddr(headers + app_from_offs)));
        if (ap) strcpy( return_path, ap );
    }

    /* cons up a list of local recipients */
    xmit_names = (struct idlist *)NULL;
    bad_addresses = good_addresses = 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(headers + env_offs, ctl, &xmit_names);
        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, &xmit_names);
        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(headers+to_addrchain->offset, ctl, &xmit_names);
                nextptr = to_addrchain->next;
                free(to_addrchain);
                to_addrchain = nextptr;
            }
        }
        if (!accept_count)
        {
            no_local_matches = TRUE;
            save_str(&xmit_names, XMIT_ACCEPT, user);
            if (outlevel == O_VERBOSE)
                error(0, 0, 
                      "no local matches, forwarding to %s",
                      user);
        }
    }
    else        /* it's a single-drop box, use first localname */
        save_str(&xmit_names, XMIT_ACCEPT, ctl->localnames->id);


    /*
     * 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_VERBOSE)
            error(0,0, "forwarding and deletion suppressed due to DNS errors");
        free(headers);
        free_str_list(&xmit_names);
        return(PS_TRANSIENT);
    }
    else if (ctl->mda)          /* we have a declared MDA */
    {
        int     length = 0;
        char    *names, *before, *after;

        for (idp = xmit_names; idp; idp = idp->next)
            if (idp->val.num == XMIT_ACCEPT)
                good_addresses++;

        destaddr = "localhost";

        length = strlen(ctl->mda) + 1;
        before = xstrdup(ctl->mda);

        /* sub user addresses for %T (or %s for backward compatibility) */
        cp = (char *)NULL;
        if (strstr(before, "%s") || (cp = strstr(before, "%T")))
        {
            char        *sp;

            if (cp && cp[1] == 'T')
                cp[1] = 's';

            /* \177 had better be out-of-band for MDA commands */
            for (sp = before; *sp; sp++)
                if (*sp == '%' && sp[1] != 's' && sp[1] != 'T')
                    *sp = '\177';

            /*
             * We go through this in order to be able to handle very
             * long lists of users and (re)implement %s.
             */
            for (idp = xmit_names; idp; idp = idp->next)
                if (idp->val.num == XMIT_ACCEPT)
                    length += (strlen(idp->id) + 1);

            names = (char *)xmalloc(++length);
            names[0] = '\0';
            for (idp = xmit_names; idp; idp = idp->next)
                if (idp->val.num == XMIT_ACCEPT)
                {
                    strcat(names, idp->id);
                    strcat(names, " ");
                }
            after = (char *)xmalloc(length);
#ifdef SNPRINTF
            snprintf(after, length, before, names);
#else
            sprintf(after, before, names);
#endif /* SNPRINTF */
            free(names);
            free(before);
            before = after;

            for (sp = before; *sp; sp++)
                if (*sp == '\177')
                    *sp = '%';
        }

        /* substitute From address for %F */
        if ((cp = strstr(before, "%F")))
        {
            char *from = return_path;
            char        *sp;

            /* \177 had better be out-of-band for MDA commands */
            for (sp = before; *sp; sp++)
                if (*sp == '%' && sp[1] != 'F')
                    *sp = '\177';

            length += strlen(from);
            after = (char *)xmalloc(length);
            cp[1] = 's';
#ifdef SNPRINTF
            snprintf(after, length, before, from);
#else
            sprintf(after, before, from);
#endif /* SNPRINTF */
            free(before);
            before = after;

            for (sp = before; *sp; sp++)
                if (*sp == '\177')
                    *sp = '%';
        }

        if (outlevel == O_VERBOSE)
            error(0, 0, "about to deliver with: %s", before);

#ifdef HAVE_SETEUID
        /*
         * Arrange to run with user's permissions if we're root.
         * This will initialize the ownership of any files the
         * MDA creates properly.  (The seteuid call is available
         * under all BSDs and Linux)
         */
        seteuid(ctl->uid);
#endif /* HAVE_SETEUID */

        sinkfp = popen(before, "w");
        free(before);

#ifdef HAVE_SETEUID
        /* this will fail quietly if we didn't start as root */
        seteuid(0);
#endif /* HAVE_SETEUID */

        if (!sinkfp)
        {
            error(0, 0, "MDA open failed");
            free(headers);
            free_str_list(&xmit_names);
            return(PS_IOERR);
        }

        sigchld = signal(SIGCHLD, SIG_DFL);
    }
    else
    {
        char    *ap, *ctt, options[MSGBUFSIZE], addr[128];

        /* build a connection to the SMTP listener */
        if ((smtp_open(ctl) == -1))
        {
            error(0, errno, "SMTP connect to %s failed",
                  ctl->smtphost ? ctl->smtphost : "localhost");
            free(headers);
            free_str_list(&xmit_names);
            return(PS_SMTP);
        }

        /*
         * Compute ESMTP options.  It's a kluge to use nxtaddr()
         * here because the contents of the Content-Transfer-Encoding
         * headers isn't semantically an address.  But it has the
         * desired tokenizing effect.
         */
        options[0] = '\0';
        if (ctl->server.esmtp_options & ESMTP_8BITMIME)
            if (ctl->pass8bits)
                strcpy(options, " BODY=8BITMIME");
            else if ((ctt_offs >= 0) && (ctt = nxtaddr(headers + ctt_offs)))
            {
                if (!strcasecmp(ctt,"7BIT"))
                    strcpy(options, " BODY=7BIT");
                else if (!strcasecmp(ctt,"8BIT"))
                    strcpy(options, " BODY=8BITMIME");
            }
        if ((ctl->server.esmtp_options & ESMTP_SIZE) && reallen > 0)
            sprintf(options + strlen(options), " SIZE=%ld", reallen);

        /*
         * Try to get the SMTP listener to take the Return-Path
         * address as MAIL FROM .  If it won't, fall back on the
         * calling-user ID.  This won't affect replies, which use the
         * header From address anyway.
         *
         * RFC 1123 requires that the domain name part of the
         * MAIL FROM address be "canonicalized", that is a
         * FQDN or MX but not a CNAME.  We'll assume the From
         * header is already in this form here (it certainly
         * is if rewrite is on).  RFC 1123 is silent on whether
         * a nonexistent hostname part is considered canonical.
         *
         * This is a potential problem if the MTAs further upstream
         * didn't pass canonicalized From/Return-Path lines, *and* the
         * local SMTP listener insists on them.
         */
        ap = (return_path[0]) ? return_path : user;
        if (SMTP_from(ctl->smtp_socket, ap, options) != SM_OK)
        {
            int smtperr = atoi(smtp_response);

            /*
             * Suppress error message only if the response specifically 
             * means `excluded for policy reasons'.  We *should* see
             * an error when the return code is less specific.
             */
            if (smtperr >= 400 && smtperr != 571)
                error(0, -1, "SMTP error: %s", smtp_response);

            switch (smtperr)
            {
            case 571:   /* sendmail's "unsolicited email refused" */
            case 501:   /* exim's old antispam response */
            case 550:   /* exim's new antispam response (temporary) */
                /*
                 * SMTP listener explicitly refuses to deliver
                 * mail coming from this address, probably due
                 * to an anti-spam domain exclusion.  Respect
                 * this.  Don't try to ship the message, and
                 * don't prevent it from being deleted.
                 */
                free(headers);
                free_str_list(&xmit_names);
                return(PS_REFUSED);

            case 452: /* insufficient system storage */
                /*
                 * Temporary out-of-queue-space condition on the
                 * ESMTP server.  Don't try to ship the message, 
                 * and suppress deletion so it can be retried on
                 * a future retrieval cycle.
                 */
                SMTP_rset(ctl->smtp_socket);    /* required by RFC1870 */
                free(headers);
                free_str_list(&xmit_names);
                return(PS_TRANSIENT);

            case 552: /* message exceeds fixed maximum message size */
                /*
                 * Permanent no-go condition on the
                 * ESMTP server.  Don't try to ship the message, 
                 * and allow it to be deleted.
                 */
                SMTP_rset(ctl->smtp_socket);    /* required by RFC1870 */
                free(headers);
                free_str_list(&xmit_names);
                return(PS_REFUSED);

            default:    /* retry with invoking user's address */
                if (SMTP_from(ctl->smtp_socket, user, options) != SM_OK)
                {
                    error(0, -1, "SMTP error: %s", smtp_response);
                    free(headers);
                    free_str_list(&xmit_names);
                    return(PS_SMTP);    /* should never happen */
                }
            }
        }

        /*
         * Now list the recipient addressees
         *
         * RFC 1123 requires that the domain name part of the
         * RCPT TO address be "canonicalized", that is a FQDN
         * or MX but not a CNAME.  Some listeners (like exim)
         * enforce this.
         */
        destaddr = ctl->smtpaddress ? ctl->smtpaddress : ( ctl->smtphost ? ctl->smtphost : "localhost");
        
        for (idp = xmit_names; idp; idp = idp->next)
            if (idp->val.num == XMIT_ACCEPT)
            {
                if (strchr(idp->id, '@'))
                    strcpy(addr, idp->id);
                else
#ifdef HAVE_SNPRINTF
                    snprintf(addr, sizeof(addr)-1, "%s@%s", idp->id, destaddr);
#else
                    sprintf(addr, "%s@%s", idp->id, destaddr);
#endif /* HAVE_SNPRINTF */

                if (SMTP_rcpt(ctl->smtp_socket, addr) == SM_OK)
                    good_addresses++;
                else
                {
                    bad_addresses++;
                    idp->val.num = XMIT_ANTISPAM;
                    error(0, 0, 
                          "SMTP listener doesn't like recipient address `%s'",
                          addr);
                }
            }
        if (!good_addresses)
        {
#ifdef HAVE_SNPRINTF
            snprintf(addr, sizeof(addr)-1, "%s@%s", user, destaddr);
#else
            sprintf(addr, "%s@%s", user, destaddr);
#endif /* HAVE_SNPRINTF */

            if (SMTP_rcpt(ctl->smtp_socket, addr) != SM_OK)
            {
                error(0, 0, "can't even send to calling user!");
                free(headers);
                free_str_list(&xmit_names);
                return(PS_SMTP);
            }
        }

        /* tell it we're ready to send data */
        SMTP_data(ctl->smtp_socket);
    }

    n = 0;
    /*
     * Some server/sendmail combinations cause problems when our
     * synthetic Received line is before the From header.  Cope
     * with this...
     */
    if ((rcv = strstr(headers, "Received:")) == (char *)NULL)
        rcv = headers;
    if (rcv > headers)
    {
        *rcv = '\0';
        n = stuffline(ctl, headers);
        *rcv = 'R';
    }
    if (!use_invisible && n != -1)
    {
        /* utter any per-message Received information we need here */
        sprintf(buf, "Received: from %s\n", ctl->server.truename);
        n = stuffline(ctl, buf);
        if (n != -1)
        {
            /*
             * 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 (fetchmail-%s %s)\n",
                    fetchmailhost, 
                    RELEASE_ID,
                    protocol->name);
            n = stuffline(ctl, buf);
            if (n != -1)
            {
                time_t  now;

                buf[0] = '\t';
                if (good_addresses == 0)
                {
                    sprintf(buf+1, 
                            "for <%s@%s> (by default); ",
                            user, destaddr);
                }
                else if (good_addresses == 1)
                {
                    for (idp = xmit_names; idp; idp = idp->next)
                        if (idp->val.num == XMIT_ACCEPT)
                            break;      /* only report first address */
                    if (strchr(idp->id, '@'))
                        sprintf(buf+1, "for <%s>", idp->id);
                    else
                        sprintf(buf+1, "for <%s/%s>", idp->id, destaddr);
                    sprintf(buf+strlen(buf), " (%s); ",
                            MULTIDROP(ctl) ? "multi-drop" : "single-drop");
                }
                else
                    buf[1] = '\0';

                time(&now);
#ifdef HAVE_STRFTIME
                /*
                 * Conform to RFC822.  This is typically going to emit
                 * a three-letter timezone for %Z, which is going to
                 * be marked "obsolete syntax" in 822bis.  Note that we
                 * generate a 4-digit year here.
                 */
                strftime(buf + strlen(buf), sizeof(buf) - strlen(buf), 
                         "%a, %d %b %Y %H:%M:%S %Z\n", localtime(&now));
#else
                /*
                 * This is really just a portability fallback, as the
                 * date format ctime(3) emits is not RFC822
                 * conformant.
                 */
                strcat(buf, ctime(&now));
#endif /* HAVE_STRFTIME */
                n = stuffline(ctl, buf);
            }
        }
    }

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

    if (n == -1)
    {
        error(0, errno, "writing RFC822 headers");
        if (ctl->mda)
        {
            if (sinkfp)
                pclose(sinkfp);
            signal(SIGCHLD, sigchld);
        }
        free(headers);
        free_str_list(&xmit_names);
        return(PS_IOERR);
    }
    else if (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 = xmit_names; idp; idp = idp->next)
                    if (idp->val.num == 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 = xmit_names; idp; idp = idp->next)
                if (idp->val.num == XMIT_ANTISPAM)
                    errlen += strlen(idp->id) + 2;

            errmsg = alloca(errlen+3);
            (void) strcpy(errmsg, errhd);
            for (idp = xmit_names; idp; idp = idp->next)
                if (idp->val.num == XMIT_ANTISPAM)
                {
                    strcat(errmsg, idp->id);
                    if (idp->next)
                        strcat(errmsg, ", ");
                }

        }

        strcat(errmsg, "\n");

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

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

    free(headers);
    free_str_list(&xmit_names);
    return(PS_SUCCESS);
}

static int readbody(sock, ctl, forward, len)
/* read and dispose of a message body presented on sock */
struct query *ctl;      /* query control record */
int sock;               /* to which the server is connected */
int len;                /* length of message */
flag forward;           /* TRUE to forward */
{
    int linelen;
    char buf[MSGBUFSIZE+1];

    /* pass through the text lines */
    while (protocol->delimited || len > 0)
    {
        if ((linelen = SockRead(sock, buf, sizeof(buf)-1)) == -1)
        {
            if (ctl->mda)
            {
                if (sinkfp)
                    pclose(sinkfp);
                signal(SIGCHLD, sigchld);
            }
            return(PS_SOCKET);
        }
        set_timeout(ctl->server.timeout);

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

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

        msglen += linelen;

        /* ship out the text line */
        if (forward)
        {
            int n = stuffline(ctl, buf);

            if (n < 0)
            {
                error(0, errno, "writing message text");
                if (ctl->mda)
                {
                    if (sinkfp)
                        pclose(sinkfp);
                    signal(SIGCHLD, sigchld);
                }
                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;
  
    ticket = ((KTEXT) (malloc (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"));
    free (ticket);
    if (rem != KSUCCESS)
    {
        error(0, -1, "kerberos error %s", (krb_get_err_text (rem)));
        return (PS_AUTHFAIL);
    }
    return (0);
}
#endif /* KERBEROS_V4 */

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, sock = -1;
    char *msg;
    void (*sigsave)();

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

    /* 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);
    }

    protocol = proto;
    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);
    set_timeout(mytimeout = ctl->server.timeout);

    if ((js = setjmp(restart)) == 1)
    {
        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
            error(0, 0, "timeout after %d seconds.", ctl->server.timeout);

        if (ctl->smtp_socket != -1)
            close(ctl->smtp_socket);
        if (sock != -1)
            close(sock);
        if (sinkfp)
            pclose(sinkfp);
        ok = PS_ERROR;
    }
    else
    {
        char buf [POPBUFSIZE+1], *realhost;
        int *msgsizes, len, num, count, new, deletions = 0;
#if INET6
        int fetches, dispatches;
#else /* INET6 */
        int port, fetches, dispatches;
#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 */
#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)
#else /* INET6 */
        if ((sock = SockOpen(realhost, port, NULL)) == -1)
#endif /* INET6 */
        {
#if !INET6
#ifndef EHOSTUNREACH
#define EHOSTUNREACH (-1)
#endif
            if (outlevel == O_VERBOSE || errno != EHOSTUNREACH)
            {
                error_build("fetchmail: %s connection to %s failed: ", 
                             protocol->name, ctl->server.pollname);
#ifdef HAVE_RES_SEARCH
                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 if (h_errno)
                    error_complete(0, 0, "unknown DNS error %d", h_errno);
                else
#endif /* HAVE_RES_SEARCH */
                    error_complete(0, errno, "local error");
            }
#endif /* INET6 */
            ok = PS_SOCKET;
            goto closeUp;
        }

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

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

        /* try to get authorized to fetch mail */
        if (protocol->getauth)
        {
            shroud = ctl->password;
            ok = (protocol->getauth)(sock, ctl, buf);
            shroud = (char *)NULL;
            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);
                }
                goto cleanUp;
            }
            set_timeout(ctl->server.timeout);
        }

        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_VERBOSE)
                    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);
                if (ok != 0)
                    goto cleanUp;
                set_timeout(ctl->server.timeout);

                /* 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(0, 0, "%d message%s (%d seen) for %s.",
                                  count, count > 1 ? "s" : "", count-new, buf);
                        else
                            error(0, 0, "%d message%s for %s.", 
                                  count, count > 1 ? "s" : "", buf);
                    }
                    else
                    {
                        /* these are pointless in normal daemon mode */
                        if (pass == 1 && (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 POP3 and
                     * IMAP2BIS you can't fetch a message without
                     * having it marked `seen'.  In IMAP4, on the
                     * other hand, you can (peek_capable is set to
                     * convey this).
                     *
                     * 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);

                    /* 
                     * 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 (proto->getsizes)
                    {
                        int     i;

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

                        ok = (proto->getsizes)(sock, count, msgsizes);
                        if (ok != 0)
                            goto cleanUp;
                        set_timeout(ctl->server.timeout);
                    }

                    /* read, forward, and delete messages */
                    for (num = 1; num <= count; num++)
                    {
                        flag toolarge = NUM_NONZERO(ctl->limit)
                            && msgsizes && (msgsizes[num-1] > ctl->limit);
                        flag fetch_it = !toolarge 
                            && (ctl->fetchall || force_retrieval || !(protocol->is_old && (protocol->is_old)(sock,ctl,num)));
                        flag suppress_delete = FALSE;
                        flag suppress_forward = 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)
                                    error_build(" (oversized, %d bytes)",
                                                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;
                            set_timeout(ctl->server.timeout);

                            /* -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 %sbytes)",
                                        len, wholesize ? "" : "header ");
                                if (outlevel == O_VERBOSE)
                                    error_complete(0, 0, "");
                                else
                                    error_build(" ");
                            }

                            /* later we'll test for this before closing */
                            sinkfp = (FILE *)NULL;

                            /* 
                             * 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)
                                goto cleanUp;
                            set_timeout(ctl->server.timeout);

                            /* 
                             * 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
                             * read_headers.
                             */
                            if (protocol->fetch_body) 
                            {
                                if (outlevel == O_VERBOSE)
                                    fputc('\n', stderr);

                                if ((ok = (protocol->trail)(sock, ctl, num)))
                                    goto cleanUp;
                                set_timeout(ctl->server.timeout);
                                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 bytes) ", len);
                                    set_timeout(ctl->server.timeout);
                                }
                            }

                            /* process the body now */
                            if (len > 0)
                            {
                                ok = readbody(sock,
                                              ctl,
                                              !suppress_forward,
                                              len);
                                if (ok == PS_TRANSIENT)
                                    suppress_delete = suppress_forward = TRUE;
                                else if (ok)
                                    goto cleanUp;
                                set_timeout(ctl->server.timeout);

                                /* 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;
                                    set_timeout(ctl->server.timeout);
                                }
                            }

                            /* 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_VERBOSE)
                                    error(0, 0,
                                          "message %d was not the expected length (%d != %d)",
                                          num, msglen, msgsizes[num-1]);
                            }

                            /* end-of-message processing starts here */

                            if (ctl->mda)
                            {
                                int rc;

                                /* close the delivery pipe, we'll reopen before next message */
                                if (sinkfp)
                                    rc = pclose(sinkfp);
                                else
                                    rc = 0;
                                signal(SIGCHLD, sigchld);
                                if (rc)
                                {
                                    error(0, -1, "MDA exited abnormally or returned nonzero status");
                                    goto cleanUp;
                                }
                            }
                            else if (!suppress_forward)
                            {
                                /* write message terminator */
                                if (SMTP_eom(ctl->smtp_socket) != SM_OK)
                                {
                                    error(0, -1, "SMTP listener refused delivery");
                                    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.num == num)
                                    MARK_SEEN(sdp->val.num);
                        }

                        /* 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;
                            set_timeout(ctl->server.timeout);
#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)
                            goto no_error;
                    }
                }
            } 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:
        set_timeout(ctl->server.timeout);
        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;
        set_timeout(0);
        close(sock);
        goto closeUp;

    cleanUp:
        set_timeout(ctl->server.timeout);
        if (ok != 0 && ok != PS_SOCKET)
            (protocol->logout_cmd)(sock, ctl);
        set_timeout(0);
        close(sock);
    }

    msg = (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, ... )
/* assemble command in printf(3) style and send to the server */
#else
void gen_send(sock, fmt, va_alist)
/* assemble command in printf(3) style and send to the server */
int sock;               /* socket to which server is connected */
const char *fmt;        /* printf-style format */
va_dcl
#endif
{
    char buf [POPBUFSIZE+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_VERBOSE)
    {
        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;
    if (SockRead(sock, buf, size) == -1)
    {
        phase = oldphase;
        return(PS_SOCKET);
    }
    else
    {
        if (buf[strlen(buf)-1] == '\n')
            buf[strlen(buf)-1] = '\0';
        if (buf[strlen(buf)-1] == '\r')
            buf[strlen(buf)-1] = '\r';
        if (outlevel == O_VERBOSE)
            error(0, 0, "%s< %s", protocol->name, buf);
        phase = oldphase;
        return(PS_SUCCESS);
    }
}

#if defined(HAVE_STDARG_H)
int gen_transact(int sock, char *fmt, ... )
/* assemble command in printf(3) style, send to server, accept a response */
#else
int gen_transact(int sock, fmt, va_alist)
/* assemble command in printf(3) style, send to server, accept a response */
int sock;               /* socket to which server is connected */
const char *fmt;        /* printf-style format */
va_dcl
#endif
{
    int ok;
    char buf [POPBUFSIZE+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_VERBOSE)
    {
        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);
    set_timeout(mytimeout);

    phase = oldphase;
    return(ok);
}

/* driver.c ends here */