Teach boring old mail(1) about the use of the REPLYTO environment

variable which is de-facto standard for MUAs.

Teach bomail to generate an in-reply-to header so threading MUAs and
mail->news gateways won't lose context.

While i was at it, removed two gratuitous standard violations for
functions starting with an underscore.

9 files changed, 64 insertions, 22 deletions

diff --git a/usr.bin/mail/cmd3.c b/usr.bin/mail/cmd3.c
index bb0c1e5..b4d7d44 100644
--- a/usr.bin/mail/cmd3.c
+++ b/usr.bin/mail/cmd3.c
@@ -187,9 +187,9 @@ respond(msgvec)
 	int *msgvec;
 {
 	if (value("Replyall") == NOSTR)
-		return (_respond(msgvec));
+		return (dorespond(msgvec));
 	else
-		return (_Respond(msgvec));
+		return (doRespond(msgvec));
 }
 
 /*
@@ -197,7 +197,7 @@ respond(msgvec)
  * message header and send them off to mail1()
  */
 int
-_respond(msgvec)
+dorespond(msgvec)
 	int *msgvec;
 {
 	struct message *mp;
@@ -252,6 +252,9 @@ _respond(msgvec)
 		head.h_cc = NIL;
 	head.h_bcc = NIL;
 	head.h_smopts = NIL;
+	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
+		head.h_replyto = NOSTR;
+	head.h_inreplyto = skin(hfield("message-id", mp));
 	mail1(&head, 1);
 	return(0);
 }
@@ -581,9 +584,9 @@ Respond(msgvec)
 	int *msgvec;
 {
 	if (value("Replyall") == NOSTR)
-		return (_Respond(msgvec));
+		return (doRespond(msgvec));
 	else
-		return (_respond(msgvec));
+		return (dorespond(msgvec));
 }
 
 /*
@@ -592,13 +595,14 @@ Respond(msgvec)
  * reply.
  */
 int
-_Respond(msgvec)
+doRespond(msgvec)
 	int msgvec[];
 {
 	struct header head;
 	struct message *mp;
 	register int *ap;
 	register char *cp;
+	char *mid;
 
 	head.h_to = NIL;
 	for (ap = msgvec; *ap != 0; ap++) {
@@ -608,6 +612,7 @@ _Respond(msgvec)
 		if ((cp = skin(hfield("from", mp))) == NOSTR)
 			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 == NIL)
 		return 0;
@@ -618,6 +623,9 @@ _Respond(msgvec)
 	head.h_cc = NIL;
 	head.h_bcc = NIL;
 	head.h_smopts = NIL;
+	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
+		head.h_replyto = NOSTR;
+	head.h_inreplyto = mid;
 	mail1(&head, 1);
 	return 0;
 }
diff --git a/usr.bin/mail/collect.c b/usr.bin/mail/collect.c
index ab3a9a3..97f0794 100644
--- a/usr.bin/mail/collect.c
+++ b/usr.bin/mail/collect.c
@@ -232,13 +232,22 @@ cont:
 			break;
 		case 's':
 			/*
-			 * Set the Subject list.
+			 * Set the Subject line.
 			 */
 			cp = &linebuf[2];
 			while (isspace(*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/usr.bin/mail/def.h b/usr.bin/mail/def.h
index 6ed65a4..f4f417a 100644
--- a/usr.bin/mail/def.h
+++ b/usr.bin/mail/def.h
@@ -155,12 +155,14 @@ 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
@@ -172,6 +174,8 @@ struct header {
 	char *h_subject;		/* Subject 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/usr.bin/mail/extern.h b/usr.bin/mail/extern.h
index 508e281..24b7608 100644
--- a/usr.bin/mail/extern.h
+++ b/usr.bin/mail/extern.h
@@ -77,8 +77,8 @@ int	 More __P((int *));
 int	 Pclose __P((FILE *));
 int	 Respond __P((int *));
 int	 Type __P((int *));
-int	 _Respond __P((int []));
-int	 _respond __P((int *));
+int	 doRespond __P((int []));
+int	 dorespond __P((int *));
 void	 alter __P((char *));
 int	 alternates __P((char **));
 void	 announce __P((void));
@@ -162,7 +162,7 @@ void	 load __P((char *));
 struct var *
 	 lookup __P((char []));
 int	 mail __P((struct name *,
-	    struct name *, struct name *, struct name *, char *));
+	    struct name *, struct name *, struct name *, char *, char *));
 void	 mail1 __P((struct header *, int));
 void	 makemessage __P((FILE *));
 void	 mark __P((int));
diff --git a/usr.bin/mail/mail.1 b/usr.bin/mail/mail.1
index 61c4dad..90fee5d 100644
--- a/usr.bin/mail/mail.1
+++ b/usr.bin/mail/mail.1
@@ -30,7 +30,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"	@(#)mail.1	8.2 (Berkeley) 12/30/93
-.\"	$Id: mail.1,v 1.12 1997/02/22 19:56:06 peter Exp $
+.\"	$Id: mail.1,v 1.13 1997/11/01 00:56:15 jraynard Exp $
 .\"
 .Dd December 30, 1993
 .Dt MAIL 1
@@ -752,6 +752,10 @@ in your home directory if
 is set.
 .It Ic \&~r Ns Ar filename
 Read the named file into the message.
+.It Ic \&~R Ns Ar string
+Use
+.Ar string
+as the Reply-To field.
 .It Ic \&~s Ns Ar string
 Cause the named string to become the current subject field.
 .It Ic \&~\&t Ns Ar name ...
@@ -924,6 +928,9 @@ 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 \&!
diff --git a/usr.bin/mail/main.c b/usr.bin/mail/main.c
index d6499bb..7c66fa4 100644
--- a/usr.bin/mail/main.c
+++ b/usr.bin/mail/main.c
@@ -61,8 +61,8 @@ main(argc, argv)
 {
 	register int i;
 	struct name *to, *cc, *bcc, *smopts;
-	char *subject;
-	char *ef;
+	char *subject, *replyto;
+	char *ef, *cp;
 	char nosrc = 0;
 	void hdrstop();
 	sig_t prevint;
@@ -90,6 +90,7 @@ main(argc, argv)
 	bcc = NIL;
 	smopts = NIL;
 	subject = NOSTR;
+	replyto = NOSTR;
 	while ((i = getopt(argc, argv, "INT:b:c:dfins:u:v")) != -1) {
 		switch (i) {
 		case 'T':
@@ -220,6 +221,8 @@ Usage: mail [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...\n\
 			if (*s != '\0')
 				load(s);
 	}
+	if ((cp = getenv("REPLYTO")) != NULL)
+		replyto = cp;
 		
 	/*
 	 * Expand returns a savestr, but load only uses the file name
@@ -227,7 +230,7 @@ Usage: mail [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...\n\
 	 */
 	load(expand("~/.mailrc"));
 	if (!rcvmode) {
-		mail(to, cc, bcc, smopts, subject);
+		mail(to, cc, bcc, smopts, subject, replyto);
 		/*
 		 * why wait?
 		 */
diff --git a/usr.bin/mail/misc/mail.tildehelp b/usr.bin/mail/misc/mail.tildehelp
index 0b1ab13..9c17176 100644
--- a/usr.bin/mail/misc/mail.tildehelp
+++ b/usr.bin/mail/misc/mail.tildehelp
@@ -12,6 +12,7 @@ The following ~ escapes are defined:
 ~p		Print the message buffer
 ~m messages	Read in messages, right shifted by a tab
 ~M messages	Same as ~m, but keep all header lines
+~R address	Set reply-to
 ~s subject	Set subject
 ~t users	Add users to to list
 ~v		Invoke display editor on message
diff --git a/usr.bin/mail/names.c b/usr.bin/mail/names.c
index e17e9f2..2050942 100644
--- a/usr.bin/mail/names.c
+++ b/usr.bin/mail/names.c
@@ -261,7 +261,8 @@ outof(names, fo, hp)
 			}
 			(void) fcntl(image, F_SETFD, 1);
 			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/usr.bin/mail/send.c b/usr.bin/mail/send.c
index 063e6ad..f9b7c87 100644
--- a/usr.bin/mail/send.c
+++ b/usr.bin/mail/send.c
@@ -251,9 +251,9 @@ statusput(mp, obuf, prefix)
  * which does all the dirty work.
  */
 int
-mail(to, cc, bcc, smopts, subject)
+mail(to, cc, bcc, smopts, subject, replyto)
 	struct name *to, *cc, *bcc, *smopts;
-	char *subject;
+	char *subject, *replyto;
 {
 	struct header head;
 
@@ -262,6 +262,8 @@ mail(to, cc, bcc, smopts, subject)
 	head.h_cc = cc;
 	head.h_bcc = bcc;
 	head.h_smopts = smopts;
+	head.h_replyto = replyto;
+	head.h_inreplyto = NOSTR;
 	mail1(&head, 0);
 	return(0);
 }
@@ -282,6 +284,9 @@ sendmail(str)
 	head.h_cc = NIL;
 	head.h_bcc = NIL;
 	head.h_smopts = NIL;
+	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
+		head.h_replyto = NOSTR;
+	head.h_inreplyto = NOSTR;
 	mail1(&head, 0);
 	return(0);
 }
@@ -437,7 +442,7 @@ infix(hp, fi)
 		return(fi);
 	}
 	(void) rm(tempMail);
-	(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);
@@ -483,6 +488,10 @@ puthead(hp, fo, w)
 		fmt("Cc:", hp->h_cc, fo, w&GCOMMA), gotcha++;
 	if (hp->h_bcc != NIL && w & GBCC)
 		fmt("Bcc:", hp->h_bcc, fo, w&GCOMMA), gotcha++;
+	if (hp->h_replyto != NOSTR && w && GREPLYTO)
+		fprintf(fo, "Reply-To: %s\n", hp->h_replyto), gotcha++;
+	if (hp->h_inreplyto != NOSTR && w && GINREPLYTO)
+		fprintf(fo, "In-Reply-To: <%s>\n", hp->h_inreplyto), gotcha++;
 	if (gotcha && w & GNL)
 		(void) putc('\n', fo);
 	return(0);