Initial revision

svn path=/trunk/; revision=3347

1 files changed, 1405 insertions, 0 deletions

diff --git a/transact.c b/transact.c
new file mode 100644
index 00000000..42145978
--- /dev/null
+++ b/transact.c
@@ -0,0 +1,1405 @@
+/*
+ * transact.c -- transaction primitives for the fetchmail driver loop
+ *
+ * Copyright 2001 by Eric S. Raymond
+ * For license terms, see the file COPYING in this directory.
+ *
+ * 
+ */
+
+#include  "config.h"
+#include  <stdio.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
+
+#ifdef HAVE_NET_SOCKET_H
+#include <net/socket.h>
+#endif
+
+#include "i18n.h"
+#include "socket.h"
+#include "fetchmail.h"
+
+#ifndef strstr		/* glibc-2.1 declares this as a macro */
+extern char *strstr();	/* needed on sysV68 R3V7.1. */
+#endif /* strstr */
+
+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 stage;		/* where are we? */
+int phase;		/* where are we, for error-logging purposes? */
+int mytimeout;		/* value of nonreponse timeout */
+int suppress_tags;	/* emit tags? */
+char shroud[PASSWORDLEN];	/* string to shroud in debug output */
+struct msgblk msgblk;
+
+char tag[TAGLEN];
+static int tagnum;
+#define GENSYM	(sprintf(tag, "A%04d", ++tagnum % TAGMOD), tag)
+
+static int accept_count, reject_count;
+static struct method *protocol;
+
+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)
+	    report(stdout, _("mapped %s to local %s\n"), 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)
+			    report(stdout, _("passed through %s matching %s\n"), 
+				  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:;
+	    }
+	}
+    }
+}
+
+/*
+ * Return zero on a syntactically invalid address, nz on a valid one.
+ *
+ * This used to be strchr(a, '.'), but it turns out that lines like this
+ *
+ * Received: from punt-1.mail.demon.net by mailstore for markb@ordern.com
+ *          id 938765929:10:27223:2; Fri, 01 Oct 99 08:18:49 GMT
+ *
+ * are not uncommon.  So now we just check that the following token is
+ * not itself an email address.
+ */
+#define VALID_ADDRESS(a)	!strchr(a, '@')
+
+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)
+	report(stdout, _("analyzing Received line:\n%s"), bufp);
+
+    /* search for whitepace-surrounded "by" followed by valid address */
+    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 valid address */
+	    if (VALID_ADDRESS(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)
+		report(stdout, 
+		      _("line accepted, %s is an alias of the mailserver\n"), rbuf);
+	}
+	else
+	{
+	    if (outlevel >= O_DEBUG)
+		report(stdout, 
+		      _("line rejected, %s is not an alias of the mailserver\n"), 
+		      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)
+	    report(stdout, _("no Received address found\n"));
+	return(NULL);
+    }
+    else
+    {
+	if (outlevel >= O_DEBUG) {
+	    char *lf = rbuf + strlen(rbuf)-1;
+	    *lf = '\0';
+	    if (outlevel >= O_DEBUG)
+		report(stdout, _("found Received address `%s'\n"), rbuf+2);
+	    *lf = '\n';
+	}
+	return(rbuf);
+    }
+}
+
+/* shared by readheaders and readbody */
+static int sizeticker;
+
+#define EMPTYLINE(s)	((s)[0] == '\r' && (s)[1] == '\n' && (s)[2] == '\0')
+
+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, *delivered_to;
+    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;
+
+    /*
+     * We used to free the header block unconditionally at the end of 
+     * readheaders, but it turns out that if close_sink() hits an error
+     * condition the code for sending bouncemail will actually look
+     * at the freed storage and coredump...
+     */
+    if (msgblk.headers)
+       free(msgblk.headers);
+
+    msgblk.headers = received_for = delivered_to = NULL;
+    from_offs = reply_to_offs = resent_from_offs = app_from_offs = 
+	sender_offs = resent_sender_offs = env_offs = -1;
+    oldlen = 0;
+    msgblk.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);
+		msgblk.headers = NULL;
+		return(PS_SOCKET);
+	    }
+	    set_timeout(0);
+	    linelen += n;
+	    msgblk.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';
+		}
+	    }
+
+	    /*
+	     * Decode MIME encoded headers. We MUST do this before
+	     * looking at the Content-Type / Content-Transfer-Encoding
+	     * headers (RFC 2046).
+	     */
+	    if (ctl->mimedecode)
+		UnMimeHeader(buf);
+
+	    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;
+	    }
+
+	    /*
+	     * At least one brain-dead website (netmind.com) is known to
+	     * send out robotmail that's missing the RFC822 delimiter blank
+	     * line before the body! Without this check fetchmail segfaults.
+	     * With it, we treat such messages as though they had the missing
+	     * blank line.
+	     */
+	    if (!isspace(line[0]) && !strchr(line, ':'))
+	    {
+		headers_ok = TRUE;
+		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)
+	    {
+		if ((!run.use_syslog && !isafile(1)) || run.showdots)
+		{
+		    fputc('.', stdout);
+		    fflush(stdout);
+		}
+		sizeticker -= SIZETICKER;
+	    }
+	}
+
+	/* we see an ordinary (non-header, non-message-delimiter line */
+	has_nuls = (linelen != strlen(line));
+
+	/*
+	 * When mail delivered to a multidrop mailbox on the server is
+	 * addressed to multiple people on the client machine, there
+	 * will be one copy left in the box for each recipient.  Thus,
+	 * if the mail is addressed to N people, each recipient will
+	 * get N copies.  This is bad when N > 1.
+	 *
+	 * Foil this by suppressing all but one copy of a message with
+	 * a given Message-ID.  The accept_count test ensures that
+	 * multiple pieces of email with the same Message-ID, each
+	 * with a *single* addressee (the N == 1 case), won't be 
+	 * suppressed.
+	 *
+	 * Note: This implementation only catches runs of successive
+	 * messages with the same ID, but that should be good
+	 * enough. A more general implementation would have to store
+	 * ever-growing lists of seen message-IDs; in a long-running
+	 * daemon this would turn into a memory leak even if the 
+	 * implementation were perfect.
+	 * 
+	 * Don't mess with this code casually.  It would be way too easy
+	 * to break it in a way that blackholed mail.  Better to pass
+	 * the occasional duplicate than to do that...
+	 */
+	if (MULTIDROP(ctl) && !strncasecmp(line, "Message-ID:", 11))
+	{
+	    if (ctl->lastid && !strcasecmp(ctl->lastid, line))
+	    {
+		if (accept_count > 1)
+		    return(PS_REFUSED);
+	    }
+	    else
+	    {
+		if (ctl->lastid)
+		    free(ctl->lastid);
+		ctl->lastid = strdup(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 INET6_ENABLE
+	if (strncmp(protocol->service, "pop2", 4))
+#else /* INET6_ENABLE */
+	if (protocol->port != 109)
+#endif /* INET6_ENABLE */
+#endif /* POP2_ENABLE */
+	    if (num == 1 && !strncasecmp(line, "X-IMAP:", 7)) {
+		free(line);
+		free(msgblk.headers);
+		msgblk.headers = NULL;
+		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;
+	}
+
+	/*
+	 * We remove all Delivered-To: headers.
+	 * 
+	 * This is to avoid false mail loops messages when delivering
+	 * local messages to and from a Postfix/qmail mailserver. 
+	 */
+	if (ctl->dropdelivered && !strncasecmp(line, "Delivered-To:", 13)) 
+	{
+	    if (delivered_to)
+		free(line);
+	    else 
+		delivered_to = 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
+	{
+	    char *newhdrs;
+	    int	newlen;
+
+	    newlen = oldlen + strlen(line);
+	    newhdrs = (char *) realloc(msgblk.headers, newlen + 1);
+	    if (newhdrs == NULL) {
+		free(line);
+		return(PS_IOERR);
+	    }
+	    msgblk.headers = newhdrs;
+	    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);
+	/*
+	 * Netscape 4.7 puts "Sender: zap" in mail headers.  Perverse...
+	 *
+	 * But a literal reading of RFC822 sec. 4.4.2 supports the idea
+	 * that Sender: *doesn't* have to be a working email address.
+	 *
+	 * The definition of the Sender header in RFC822 says, in
+	 * part, "The Sender mailbox specification includes a word
+	 * sequence which must correspond to a specific agent (i.e., a
+	 * human user or a computer program) rather than a standard
+	 * address."  That implies that the contents of the Sender
+	 * field don't need to be a legal email address at all So
+	 * ignore any Sender or Resent-Semnder lines unless they
+	 * contain @.
+	 *
+	 * (RFC2822 says the condents of Sender must be a valid mailbox
+	 * address, which is also what RFC822 4.4.4 implies.)
+	 */
+	else if (!strncasecmp("Sender:", line, 7) && strchr(line, '@'))
+	    sender_offs = (line - msgblk.headers);
+	else if (!strncasecmp("Resent-Sender:", line, 14) && strchr(line, '@'))
+	    resent_sender_offs = (line - msgblk.headers);
+
+#ifdef __UNUSED__
+ 	else if (!strncasecmp("Message-Id:", line, 11))
+	{
+	    if (ctl->server.uidl)
+ 	    {
+	        char id[IDLEN+1];
+
+		line[IDLEN+12] = 0;		/* prevent stack overflow */
+ 		sscanf(line+12, "%s", id);
+ 	        if (!str_find( &ctl->newsaved, num))
+		{
+ 		    struct idlist *new = save_str(&ctl->newsaved,id,UID_SEEN);
+		    new->val.status.num = num;
+		}
+ 	    }
+ 	}
+#endif /* __UNUSED__ */
+
+	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)
+	    report(stdout,
+		   _("message delimiter found while scanning headers\n"));
+    }
+
+    /*
+     * 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.
+     */
+
+    /* Check for MIME headers indicating possible 8-bit data */
+    ctl->mimemsg = MimeBodyType(msgblk.headers, ctl->mimedecode);
+
+#ifdef SDPS_ENABLE
+    if (ctl->server.sdps && sdps_envfrom)
+    {
+	/* We have the real envelope return-path, stored out of band by
+	 * SDPS - that's more accurate than any header is going to be.
+	 */
+	strcpy(msgblk.return_path, sdps_envfrom);
+	free(sdps_envfrom);
+    } else
+#endif /* SDPS_ENABLE */
+    /*
+     * 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)));
+	/* multi-line MAIL FROM addresses confuse SMTP terribly */
+	if (ap && !strchr(ap, '\n')) 
+	    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))
+    {
+#ifdef SDPS_ENABLE
+	if (ctl->server.sdps && sdps_envto)
+	{
+	    /* We have the real envelope recipient, stored out of band by
+	     * SDPS - that's more accurate than any header is going to be.
+	     */
+	    find_server_names(sdps_envto, ctl, &msgblk.recipients);
+	    free(sdps_envto);
+	} else
+#endif /* SDPS_ENABLE */ 
+	if (env_offs > -1)	    /* We have the actual envelope addressee */
+	    find_server_names(msgblk.headers + env_offs, ctl, &msgblk.recipients);
+	else if (delivered_to && ctl->server.envelope != STRING_DISABLED &&
+      ctl->server.envelope && !strcasecmp(ctl->server.envelope, "Delivered-To"))
+   {
+	    find_server_names(delivered_to, ctl, &msgblk.recipients);
+       free(delivered_to);
+   }
+	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);
+	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" addresses.
+	     */
+	    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)
+		report(stdout,
+		      _("no local matches, forwarding to %s\n"),
+		      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)
+	    report(stdout,
+		   _("forwarding and deletion suppressed due to DNS errors\n"));
+	free(msgblk.headers);
+	msgblk.headers = NULL;
+	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);
+	    msgblk.headers = NULL;
+	    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 */
+        if (ctl->server.trueaddr) {
+	    sprintf(buf, "Received: from %s [%u.%u.%u.%u]\r\n", 
+		    ctl->server.truename,
+		    (unsigned char)ctl->server.trueaddr[0],
+		    (unsigned char)ctl->server.trueaddr[1],
+		    (unsigned char)ctl->server.trueaddr[2],
+		    (unsigned char)ctl->server.trueaddr[3]);
+	} else {
+	  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.
+	     */
+	    sprintf(buf, "\tby %s with %s (fetchmail-%s)",
+		    fetchmailhost,
+		    protocol->name,
+		    VERSION);
+	    if (ctl->tracepolls)
+	    {
+		sprintf(buf + strlen(buf), " polling %s account %s",
+			ctl->server.pollname, 
+			ctl->remotename);
+	    }
+	    strcat(buf, "\r\n");
+	    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)
+    {
+	report(stdout, _("writing RFC822 msgblk.headers\n"));
+	release_sink(ctl);
+	free(msgblk.headers);
+	msgblk.headers = NULL;
+	free_str_list(&msgblk.recipients);
+	return(PS_IOERR);
+    }
+    else if ((run.poll_interval == 0 || nodetach) && outlevel >= O_VERBOSE && !isafile(2))
+	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);
+}
+
+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 in the body.
+     *
+     * Yes, this wants to be ||, not &&.  The problem is that in the most
+     * important delimited protocol, POP3, the length is not reliable.
+     * As usual, the problem is Microsoft brain damage; see FAQ item S2.
+     * So, for delimited protocols we need to ignore the length here and
+     * instead drop out of the loop with a break statement when we see
+     * the message delimiter.
+     */
+    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 (outlevel > O_SILENT && (((run.poll_interval == 0 || nodetach) && !isafile(1)) || run.showdots))
+		{
+		    fputc('.', stdout);
+		    fflush(stdout);
+		}
+		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
+		msgblk.msglen--;	/* subtract the size of the dot escape */
+	}
+
+	msgblk.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)
+	    {
+		report(stdout, _("writing message text\n"));
+		release_sink(ctl);
+		return(PS_IOERR);
+	    }
+	    else if (outlevel >= O_VERBOSE && !isafile(1))
+	    {
+		fputc('*', stdout);
+		fflush(stdout);
+	    }
+	}
+    }
+
+    return(PS_SUCCESS);
+}
+
+void init_transact(const struct method *proto)
+/* initialize state for the send and receive functions */
+{
+    tagnum = 0;
+    tag[0] = '\0';	/* nuke any tag hanging out from previous query */
+    protocol = (struct method *)proto;
+}
+
+#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 && !suppress_tags)
+	(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[0] && (cp = strstr(buf, shroud)))
+	{
+	    char	*sp;
+
+	    sp = cp + strlen(shroud);
+	    *cp++ = '*';
+	    while (*sp)
+		*cp++ = *sp++;
+	    *cp = '\0';
+	}
+	buf[strlen(buf)-2] = '\0';
+	report(stdout, "%s> %s\n", 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)
+	    report(stdout, "%s< %s\n", 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 && !suppress_tags)
+	(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';
+	report(stdout, "%s> %s\n", protocol->name, buf);
+    }
+
+    /* we presume this does its own response echoing */
+    ok = (protocol->parse_response)(sock, buf);
+
+    phase = oldphase;
+    return(ok);
+}
+
+/* transact.c ends here */