From 2090981be3d3e5ca1083c004a08f54aced2d0720 Mon Sep 17 00:00:00 2001
From: bakkeby <bakkeby@gmail.com>
Date: Mon, 20 Apr 2020 10:24:34 +0200
Subject: [PATCH] Add support for scroll(1)

Scroll is a program that stores all the lines of its child and be used in st as
a way of implementing scrollback.

This solution is much better than implementing the scrollback in st itself
because having a different program allows to use it in any other program
without doing modifications to those programs.
---
 config.def.h |  3 ++-
 st.1         |  3 ++-
 st.c         | 16 ++++++++++------
 st.h         |  3 ++-
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/config.def.h b/config.def.h
index 959a90c..52059ab 100644
--- a/config.def.h
+++ b/config.def.h
@@ -25,13 +25,14 @@ static int borderpx = 2;
 /*
  * What program is execed by st depends of these precedence rules:
  * 1: program passed with -e
- * 2: utmp option
+ * 2: scroll and/or utmp
  * 3: SHELL environment variable
  * 4: value of shell in /etc/passwd
  * 5: value of shell in config.h
  */
 static char *shell = "/bin/sh";
 char *utmp = NULL;
+char *scroll = NULL;
 char *stty_args = "stty raw pass8 nl -echo -iexten -cstopb 38400";
 
 /* identification sequence returned in DA and DECID */
diff --git a/st.1 b/st.1
index e8d6059..39120b4 100644
--- a/st.1
+++ b/st.1
@@ -170,7 +170,8 @@ See the LICENSE file for the terms of redistribution.
 .SH SEE ALSO
 .BR tabbed (1),
 .BR utmp (1),
-.BR stty (1)
+.BR stty (1),
+.BR scroll (1)
 .SH BUGS
 See the TODO file in the distribution.
 
diff --git a/st.c b/st.c
index 51a6835..9d8a9ba 100644
--- a/st.c
+++ b/st.c
@@ -726,7 +726,7 @@ die(const char *errstr, ...)
 void
 execsh(char *cmd, char **args)
 {
-	char *sh, *prog;
+	char *sh, *prog, *arg;
 	const struct passwd *pw;
 
 	errno = 0;
@@ -740,12 +740,16 @@ execsh(char *cmd, char **args)
 	if ((sh = getenv("SHELL")) == NULL)
 		sh = (pw->pw_shell[0]) ? pw->pw_shell : cmd;
 
-	if (args)
+	if (args) {
 		prog = args[0];
-	else if (utmp)
-		prog = utmp;
-	else
+		arg = NULL;
+	} else if (scroll || utmp) {
+		prog = scroll ? scroll : utmp;
+		arg = scroll ? utmp : NULL;
+	} else {
 		prog = sh;
+		arg = NULL;
+	}
 	DEFAULT(args, ((char *[]) {prog, NULL}));
 
 	unsetenv("COLUMNS");
@@ -2768,4 +2772,4 @@ redraw(void)
 	draw();
 }
 
-#include "patch/st_include.c"
\ No newline at end of file
+#include "patch/st_include.c"
diff --git a/st.h b/st.h
index f8fa2be..030de38 100644
--- a/st.h
+++ b/st.h
@@ -132,6 +132,7 @@ int borderpx;
 
 /* config.h globals */
 extern char *utmp;
+extern char *scroll;
 extern char *stty_args;
 extern char *vtiden;
 extern wchar_t *worddelimiters;
@@ -145,4 +146,4 @@ extern const int boxdraw, boxdraw_bold, boxdraw_braille;
 #endif // BOXDRAW_PATCH
 #if ALPHA_PATCH
 extern float alpha;
-#endif // ALPHA_PATCH
\ No newline at end of file
+#endif // ALPHA_PATCH