From: Robert Luberda <robert@debian.org>
Date: Mon, 2 Apr 2001 00:24:00 +0200
Subject: 10 Reply-To header

Applied some patches from FreeBSD:
 + Add Relpy-To header if REPLYTO environment variable is set.
 + Add In-Reply-To header for replies (closes: #23115).
---
 cmd3.c    |  9 +++++++++
 collect.c | 11 ++++++++++-
 def.h     | 12 ++++++++----
 extern.h  |  2 +-
 mail.1    | 10 +++++++++-
 main.c    |  9 +++++++--
 names.c   |  3 ++-
 send.c    | 15 ++++++++++++---
 8 files changed, 58 insertions(+), 13 deletions(-)

diff --git a/cmd3.c b/cmd3.c
index 172a432..255d968 100644
--- a/cmd3.c
+++ b/cmd3.c
@@ -243,6 +243,9 @@ _respond(msgvec)
 		head.h_cc = NULL;
 	head.h_bcc = NULL;
 	head.h_smopts = NULL;
+	head.h_replyto = getenv("REPLYTO");
+	head.h_inreplyto = skin(hfield("message-id", mp));
+
 	mail1(&head, 1);
 	return(0);
 }
@@ -605,8 +608,10 @@ _Respond(int *msgvec)
 	struct message *mp;
 	int *ap;
 	char *cp;
+	char *mid;
 	memset(&head, 0, sizeof(head));
 
+	mid = NULL;
 	head.h_to = NULL;
 	for (ap = msgvec; *ap != 0; ap++) {
 		mp = &message[*ap - 1];
@@ -615,6 +620,7 @@ _Respond(int *msgvec)
 		if ((cp = skin(hfield("from", mp))) == NULL)
 			cp = skin(nameof(mp, 2));
 		head.h_to = cat(head.h_to, extract(cp, GTO));
+		mid = skin(hfield("message-id", mp));
 	}
 	if (head.h_to == NULL)
 		return(0);
@@ -626,6 +632,9 @@ _Respond(int *msgvec)
 	head.h_cc = NULL;
 	head.h_bcc = NULL;
 	head.h_smopts = NULL;
+	head.h_replyto = getenv("REPLYTO");
+	head.h_inreplyto = mid;
+
 	mail1(&head, 1);
 	return(0);
 }
diff --git a/collect.c b/collect.c
index 3bc16c3..708f257 100644
--- a/collect.c
+++ b/collect.c
@@ -218,13 +218,22 @@ cont:
 			break;
 		case 's':
 			/*
-			 * Set the Subject list.
+			 * Set the Subject line.
 			 */
 			cp = &linebuf[2];
 			while (isspace((unsigned char)*cp))
 				cp++;
 			hp->h_subject = savestr(cp);
 			break;
+               case 'R':
+                       /*
+                        * Set the Reply-To line.
+                        */
+                       cp = &linebuf[2];
+                       while (isspace(*cp))
+                               cp++;
+                       hp->h_replyto = savestr(cp);
+                       break;
 		case 'c':
 			/*
 			 * Add to the CC list.
diff --git a/def.h b/def.h
index 69cd210..1c71c63 100644
--- a/def.h
+++ b/def.h
@@ -164,12 +164,14 @@ struct headline {
 #define	GSUBJECT 2		/* Likewise, Subject: line */
 #define	GCC	4		/* And the Cc: line */
 #define	GBCC	8		/* And also the Bcc: line */
-#define	GMASK	(GTO|GSUBJECT|GCC|GBCC)
+#define	GREPLYTO 0x10           /* And the Reply-To: line */
+#define	GINREPLYTO 0x20         /* The In-Reply-To: line */
+#define	GMASK   (GTO|GSUBJECT|GCC|GBCC|GREPLYTO|GINREPLYTO)
 				/* Mask of places from whence */
 
-#define	GNL	16		/* Print blank line after */
-#define	GDEL	32		/* Entity removed from list */
-#define	GCOMMA	64		/* detract puts in commas */
+#define	GNL	0x40		/* Print blank line after */
+#define	GDEL	0x80		/* Entity removed from list */
+#define	GCOMMA	0x100		/* detract puts in commas */
 
 /*
  * Structure used to pass about the current
@@ -182,6 +184,8 @@ struct header {
 	char *h_header;			/* Additional header string */
 	struct name *h_cc;		/* Carbon copies string */
 	struct name *h_bcc;		/* Blind carbon copies */
+	char *h_replyto;                /* Reply address */
+	char *h_inreplyto;              /* Reference */
 	struct name *h_smopts;		/* Sendmail options */
 };
 
diff --git a/extern.h b/extern.h
index 02cea6b..a093a9f 100644
--- a/extern.h
+++ b/extern.h
@@ -164,7 +164,7 @@ void	 load(char *);
 struct var *
 	 lookup(char *);
 int	 mail(struct name *, struct name *, struct name *, struct name *,
-	       char *, char *);
+	       char *, char *, char *);
 void	 mail1(struct header *, int);
 void	 makemessage(FILE *, int);
 void	 mark(int);
diff --git a/mail.1 b/mail.1
index f05fac4..738b215 100644
--- a/mail.1
+++ b/mail.1
@@ -838,6 +838,10 @@ Abort the message being sent, copying the message to
 in your home directory if
 .Ic save
 is set.
+.It Ic ~R Ns Ar string
+Use
+.Ar string
+as the Reply-To field.
 .Pp
 .It Ic ~r Ns Ar filename
 .It Ic ~< Ns Ar filename
@@ -1126,6 +1130,9 @@ variable is set.
 The default paginator
 .Xr more 1
 is used if this option is not defined.
+.It Ev REPLYTO
+If set, will be used to initialize the Reply-To field for outgoing
+messages.
 .It Ev SHELL
 Pathname of the shell to use in the
 .Ic !\&
@@ -1200,7 +1207,8 @@ utilizes the
 .Ev PAGER ,
 .Ev LISTER ,
 .Ev EDITOR ,
-.Ev VISUAL
+.Ev VISUAL ,
+.Ev REPLYTO ,
 .Ev MAIL ,
 .Ev MAILRC ,
 and
diff --git a/main.c b/main.c
index f8f48ae..3f75042 100644
--- a/main.c
+++ b/main.c
@@ -51,7 +51,8 @@ main(int argc, char **argv)
 	struct name *to, *cc, *bcc, *smopts;
 	char *fromaddr;
 	char *subject;
-	char *header = NULL;
+	char *replyto;
+	char *header;
 	char *ef;
 	char* cmd;
 	char nosrc = 0;
@@ -116,7 +117,10 @@ main(int argc, char **argv)
 	smopts = NULL;
 	fromaddr = NULL;
 	subject = NULL;
+	header = NULL;
+	replyto = NULL;
 	while ((i = getopt(argc, argv, "EINa:b:c:dfeinr:s:u:v")) != -1) {
+
 		switch (i) {
 		case 'u':
 			/*
@@ -260,6 +264,7 @@ main(int argc, char **argv)
 	spreserve();
 	if (!nosrc)
 		load(_PATH_MASTER_RC);
+	replyto = getenv("REPLYTO");
 	/*
 	 * Expand returns a savestr, but load only uses the file name
 	 * for fopen, so it's safe to do this.
@@ -268,7 +273,7 @@ main(int argc, char **argv)
 		rc = "~/.mailrc";
 	load(expand(rc));
 	if (!rcvmode) {
-		mail(to, cc, bcc, smopts, fromaddr, subject, header);
+		mail(to, cc, bcc, smopts, fromaddr, subject, header, replyto);
 		/*
 		 * why wait?
 		 */
diff --git a/names.c b/names.c
index 55d51df..96a1a1f 100644
--- a/names.c
+++ b/names.c
@@ -256,7 +256,8 @@ outof(struct name *names, FILE *fo, struct header *hp)
 				goto cant;
 			}
 			fprintf(fout, "From %s %s", myname, date);
-			puthead(hp, fout, GTO|GSUBJECT|GCC|GNL);
+			puthead(hp, fout,
+				GTO|GSUBJECT|GCC|GREPLYTO|GINREPLYTO|GNL);
 			while ((c = getc(fo)) != EOF)
 				(void)putc(c, fout);
 			rewind(fo);
diff --git a/send.c b/send.c
index 39524bc..015971f 100644
--- a/send.c
+++ b/send.c
@@ -280,7 +280,7 @@ statusput(struct message *mp, FILE *obuf, char *prefix)
  */
 int
 mail(struct name *to, struct name *cc, struct name *bcc, struct name *smopts,
-     char *fromaddr, char *subject, char *header)
+     char *fromaddr, char *subject, char *header, char *replyto)
 {
 	struct header head;
 
@@ -290,6 +290,8 @@ mail(struct name *to, struct name *cc, struct name *bcc, struct name *smopts,
 	head.h_header = header;
 	head.h_cc = cc;
 	head.h_bcc = bcc;
+	head.h_replyto = replyto;
+	head.h_inreplyto = NULL;
 	head.h_smopts = smopts;
 	mail1(&head, 0);
 	return(0);
@@ -311,6 +313,8 @@ sendmail(void *v)
 	head.h_header = NULL;
 	head.h_cc = NULL;
 	head.h_bcc = NULL;
+	head.h_replyto = getenv("REPLYTO");
+	head.h_inreplyto = NULL;
 	head.h_smopts = NULL;
 	mail1(&head, 0);
 	return(0);
@@ -379,7 +383,7 @@ mail1(struct header *hp, int printheaders)
         *ap++ = "-t";
 	cp = hp->h_from ? hp->h_from : value("from");
 	if (cp != NULL) {
-		envfrom = skin(cp);
+		envfrom = skin(cp, 1);
 		*ap++ = "-f";
 		*ap++ = envfrom;
 		if (envfrom == cp)
@@ -485,7 +489,8 @@ infix(struct header *hp, FILE *fi)
 		return(fi);
 	}
 	(void)rm(tempname);
-	(void)puthead(hp, nfo, GTO|GSUBJECT|GCC|GBCC|GNL|GCOMMA);
+	(void)puthead(hp, nfo,
+		      GTO|GSUBJECT|GCC|GBCC|GREPLYTO|GINREPLYTO|GNL|GCOMMA);
 	c = getc(fi);
 	while (c != EOF) {
 		(void)putc(c, nfo);
@@ -534,6 +539,10 @@ puthead(struct header *hp, FILE *fo, int w)
 		fmt("Bcc:", hp->h_bcc, fo, w&GCOMMA), gotcha++;
 	if (hp->h_header != NULL && w)
 		fprintf(fo, "%s\n", hp->h_header), gotcha++;
+        if (hp->h_replyto != NULL && w & GREPLYTO)
+                fprintf(fo, "Reply-To: %s\n", hp->h_replyto), gotcha++;
+        if (hp->h_inreplyto != NULL && w & GINREPLYTO)
+                fprintf(fo, "In-Reply-To: <%s>\n", hp->h_inreplyto), gotcha++;
 	if (gotcha && w & GNL)
 		(void)putc('\n', fo);
 	return(0);