Support leading, trailing and double colons in MANPATH to prepend,

append or insert the man.conf(5) default path; compatible with GNU
manpath(1), implementation by kristaps@, heavily tweaked by schwarze@.

Updates to MANPATH documentation applied to whatis.1, apropos.1, and
catman.8 also.

4 files changed, 81 insertions, 9 deletions

diff --git a/apropos.1 b/apropos.1
index a390d8a3..efbf216f 100644
--- a/apropos.1
+++ b/apropos.1
@@ -239,11 +239,22 @@ Text production:
 .Sh ENVIRONMENT
 .Bl -tag -width Ds
 .It Ev MANPATH
-Colon-separated paths overriding the default list of paths searched for
+Colon-separated paths modifying the default list of paths searched for
 manual databases.
 Invalid paths, or paths without manual databases, are ignored.
 Overridden by
 .Fl M .
+If
+.Ev MANPATH
+begins with a
+.Sq \&: ,
+it is appended to the default list;
+else if it ends with
+.Sq \&: ,
+it is prepended to the default list; else if it contains
+.Sq \&:: ,
+the default list is inserted between the colons.
+If none of these conditions are met, it overrides the default list.
 .El
 .Sh FILES
 .Bl -tag -width "/etc/man.conf" -compact
diff --git a/catman.8 b/catman.8
index 333d13be..a57716e7 100644
--- a/catman.8
+++ b/catman.8
@@ -80,11 +80,22 @@ is specified, all files are updated.
 .Sh ENVIRONMENT
 .Bl -tag -width Ds
 .It Ev MANPATH
-Colon-separated paths overriding the default list of paths searched for
+Colon-separated paths modifying the default list of paths searched for
 manual databases.
 Invalid paths, or paths without manual databases, are ignored.
 Overridden by
 .Fl M .
+If
+.Ev MANPATH
+begins with a
+.Sq \&: ,
+it is appended to the default list;
+else if it ends with
+.Sq \&: ,
+it is prepended to the default list; else if it contains
+.Sq \&:: ,
+the default list is inserted between the colons.
+If none of these conditions are met, it overrides the default list.
 .El
 .Sh EXIT STATUS
 .Ex -std
diff --git a/manpath.c b/manpath.c
index 9c4d254c..561911cb 100644
--- a/manpath.c
+++ b/manpath.c
@@ -87,15 +87,54 @@ manpath_parse(struct manpaths *dirs, const char *file,
 	free(buf);
 	pclose(stream);
 #else
-	manpath_parseline(dirs, auxp);
+	char		*insert;
 
-	if (NULL == defp)
-		defp = getenv("MANPATH");
+	/* Always prepend -m. */
+ 	manpath_parseline(dirs, auxp);
+ 
+	/* If -M is given, it overrides everything else. */
+	if (NULL != defp) {
+		manpath_parseline(dirs, defp);
+		return;
+	}
+
+	/* MANPATH and man.conf(5) cooperate. */
+	defp = getenv("MANPATH");
+	if (NULL == file)
+		file = MAN_CONF_FILE;
+
+	/* No MANPATH; use man.conf(5) only. */
+	if (NULL == defp || '\0' == defp[0]) {
+		manpath_manconf(dirs, file);
+		return;
+	}
+
+	/* Prepend man.conf(5) to MANPATH. */
+	if (':' == defp[0]) {
+		manpath_manconf(dirs, file);
+		manpath_parseline(dirs, defp);
+		return;
+	}
 
-	if (NULL == defp)
-		manpath_manconf(dirs, file ? file : MAN_CONF_FILE);
-	else
+	/* Append man.conf(5) to MANPATH. */
+	if (':' == defp[(int)strlen(defp) - 1]) {
 		manpath_parseline(dirs, defp);
+		manpath_manconf(dirs, file);
+		return;
+	}
+
+	/* Insert man.conf(5) into MANPATH. */
+	insert = strstr(defp, "::");
+	if (NULL != insert) {
+		*insert++ = '\0';
+		manpath_parseline(dirs, defp);
+		manpath_manconf(dirs, file);
+		manpath_parseline(dirs, insert + 1);
+		return;
+	}
+
+	/* MANPATH overrides man.conf(5) completely. */
+	manpath_parseline(dirs, defp);
 #endif
 }
 
diff --git a/whatis.1 b/whatis.1
index 0537bbaf..09dcb9ce 100644
--- a/whatis.1
+++ b/whatis.1
@@ -111,11 +111,22 @@ as follows:
 .Sh ENVIRONMENT
 .Bl -tag -width Ds
 .It Ev MANPATH
-Colon-separated paths overriding the default list of paths searched for
+Colon-separated paths modifying the default list of paths searched for
 manual databases.
 Invalid paths, or paths without manual databases, are ignored.
 Overridden by
 .Fl M .
+If
+.Ev MANPATH
+begins with a
+.Sq \&: ,
+it is appended to the default list;
+else if it ends with
+.Sq \&: ,
+it is prepended to the default list; else if it contains
+.Sq \&:: ,
+the default list is inserted between the colons.
+If none of these conditions are met, it overrides the default list.
 .El
 .Sh FILES
 .Bl -tag -width "/etc/man.conf" -compact