These paths translate From_ lines into Return-Path: in unix style mailboxes.
If the mailbox is in MMDF format, it does nothing (since MMDF has already
done the Return-Path: translation while writing the message out.

WARNING: Do not merge these patches in with other patch files.
	 Keep them separate (Andrey, I mean you).
						-- Paul Traina
						   17-Feb-1997

With old variant of this patch message size was counted incorrectly,
"rpath" variable can be referenced without initialization, second
Return-Path not skipped, fixed now.
						-- Andrey Chernov
						   8-Oct-1997

*** pop_dropcopy.c.orig	Fri Jul 25 21:42:07 1997
--- pop_dropcopy.c	Wed Oct  8 10:36:34 1997
***************
*** 151,156 ****
--- 151,187 ----
      return(ti != 0);
  }
  
+ char *
+ return_path (const char *unixfrom)
+ {
+     static char tmpbuf[BUFSIZ];
+     int fromlen = sizeof("From ") - 1;
+     const char *fp, *hp, *cp, *ep;
+ 
+     /* if it doesn't start with a From_, it's not */
+     if (strncmp(unixfrom, "From ", fromlen))
+ 	return NULL;
+ 
+     fp = unixfrom + fromlen;
+     hp = cp = strchr(fp, ' ');
+     while (hp = strchr(++hp, 'r'))
+ 	if (!strncmp(hp, "remote from", sizeof("remote from") - 1)) {
+ 	    hp = strrchr(hp, ' ');
+ 	    break;
+         }
+ 
+     if (hp) {
+ 	ep = strrchr(++hp, '\n');
+ 	snprintf(tmpbuf, sizeof(tmpbuf), "Return-Path: %.*s!%.*s\n",
+ 		 ep - hp, hp,
+ 		 cp - fp, fp);
+     } else
+ 	snprintf(tmpbuf, sizeof(tmpbuf), "Return-Path: %.*s\n",
+ 		 cp - fp, fp);
+ 
+     return tmpbuf;
+ }
+ 
  /* Hashing to a spool directory helps reduce the lookup time for sites
   * with thousands of mail spool files.  Unix uses a linear list to
   * save directory information and the following methods attempt to
***************
*** 275,280 ****
--- 306,312 ----
      char                    buffer[MAXLINELEN];		/*  Read buffer */
      MD5_CTX		    mdContext;
      unsigned char	    digest[16];
+     char                   *rpath = NULL;
  
  #ifdef DEBUG
      if(p->debug)
***************
*** 340,345 ****
--- 372,380 ----
  	    (p->mmdf_separator ? !strcmp(p->mmdf_separator, buffer) :
  	    isfromline(buffer))) {
  
+ 	    if (!p->mmdf_separator)
+ 		rpath = return_path(buffer);
+ 
  	    if (expecting_trailer) {
  		/* skip over the MMDF trailer */
  		expecting_trailer = 0;
***************
*** 385,390 ****
--- 420,428 ----
  	    mp->retr_flag = FALSE;
  	    mp->orig_retr_state = FALSE;
  	    mp->uidl_str = "\n";
+ 	    mp->return_path = rpath ? strdup(rpath) : NULL;
+ 	    if (rpath)
+ 		mp->length += strlen(rpath) + 1;
  #ifdef DEBUG
  	    if(p->debug)
  		pop_log(p,POP_DEBUG, "Msg %d being added to list", mp->number);
***************
*** 463,468 ****
--- 501,508 ----
  		    mp->retr_flag = TRUE;
  		    mp->orig_retr_state = TRUE;
  		}
+ 	    } else if (rpath && (strncasecmp(buffer,"Return-Path:",12) == 0)) {
+ 		continue;
  	    }
  	} else {
  	    content_nchar += nchar;
***************
*** 502,507 ****
--- 542,548 ----
      int			    content_length, content_nchar, cont_len;
      MD5_CTX		    mdContext;
      unsigned char	    digest[16];
+     char                   *rpath = NULL;
  
      FILE		    *mail_drop;		    /*  Streams for fids */
  
***************
*** 574,579 ****
--- 615,623 ----
  	    (p->mmdf_separator ? !strcmp(p->mmdf_separator, buffer) :
  	    isfromline(buffer))) {
  
+ 	    if (!p->mmdf_separator)
+ 		rpath = return_path(buffer);
+ 
  	    if (expecting_trailer) {
  		expecting_trailer = 0;
  		continue;
***************
*** 619,624 ****
--- 663,671 ----
              mp->retr_flag = FALSE;
              mp->orig_retr_state = FALSE;
  	    mp->uidl_str = "\n";
+ 	    mp->return_path = rpath ? strdup(rpath) : NULL;
+ 	    if (rpath)
+ 		mp->length += strlen(rpath) + 1;
  
  #ifdef DEBUG
              if(p->debug)
***************
*** 701,706 ****
--- 748,755 ----
  		    mp->retr_flag = TRUE;
  		    mp->orig_retr_state = TRUE;
  		}
+ 	    } else if (rpath && (strncasecmp(buffer,"Return-Path:",12) == 0)) {
+ 		continue;
  	    }
  	} else {
  	    content_nchar += nchar;
--- pop_send.c	Mon Feb 17 13:14:25 1997
+++ pop_send.c	Mon Feb 17 13:15:28 1997
@@ -84,6 +84,9 @@
     /*  Skip the first line (the sendmail "From" or MMDF line) */
     (void)fgets (buffer,MAXMSGLINELEN,p->drop);
 
+    if (mp->return_path)
+	pop_sendline(p, mp->return_path);
+
     /*  Send the header of the message followed by a blank line */
     while (fgets(buffer, MAXMSGLINELEN, p->drop)) {
 	if (!strncasecmp(buffer, "Content-Length:", 15) ||
--- popper.h	Mon Feb 17 13:15:44 1997
+++ popper.h	Mon Feb 17 13:35:48 1997
@@ -260,6 +263,8 @@
 						    Used for RSET cmd. */
     char	*uidl_str;			/*  Cache of the UIDL str for
 						    faster access */
+    char	*return_path;			/*  Cache of the rpath str for
+						    faster access */
 } MsgInfoList;
 
 typedef struct  {                               /*  POP parameter block */