From ad042959a56bba8478499f78dfce1ae876e092c4 Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jkk@ung.org>
Date: Sun, 23 Apr 2023 09:49:34 -0400
Subject: properly set COLUMNS and LINES

---
 interactive.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/interactive.c b/interactive.c
index 239c001..cad6867 100644
--- a/interactive.c
+++ b/interactive.c
@@ -19,13 +19,57 @@
 
 #define _XOPEN_SOURCE 700
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <signal.h>
+#include <unistd.h>
+
+#ifdef SIGWINCH
+#include <sys/ioctl.h>
+#endif
 
 #include "sh.h"
 #include "shed.h"
 
+sig_atomic_t got_sigwinch = 0;
+static char sh_columns[8] = "80";
+static char sh_lines[8] = "25";
+
+#ifdef SIGWINCH
+static void sh_sigwinch(int sig)
+{
+	got_sigwinch = 1;
+	signal(sig, sh_sigwinch);
+}
+#endif
+
+void sh_getwinsize(void)
+{
+	#ifdef TIOCGWINSZ
+		struct winsize ws = { 0 };
+		ioctl(STDIN_FILENO, TIOCGWINSZ, &ws);
+		snprintf(sh_columns, sizeof(sh_columns), "%hhu", ws.ws_col);
+		snprintf(sh_lines, sizeof(sh_lines), "%hhu", ws.ws_row);
+	#else
+		FILE *cols = popen("tput cols", "r");
+		if (cols) {
+			fread(cols, 1, sizeof(sh_columns), sh_columns);
+			fclose(cols);
+		}
+
+		FILE *lines = popen("tput lines", "r");
+		if (lines) {
+			fread(lines, 1, sizeof(sh_lines), sh_lines);
+			fclose(lines);
+		}
+	#endif
+
+	setenv("COLUMNS", sh_columns, 1);
+	setenv("LINES", sh_lines, 1);
+}
+
 int sh_interactive(void)
 {
 	struct shed ed = {
@@ -33,6 +77,11 @@ int sh_interactive(void)
 		.handle = shed_handle_non_vi,
 	};
 
+	sh_getwinsize();
+	#ifdef SIGWINCH
+	signal(SIGWINCH, sh_sigwinch);
+	#endif
+
 	while (shed(&ed) != NULL) {
 		if (ed.cur->nread == 1 && ed.cur->buf[0] == CTRL_D) {
 			printf("\n");
@@ -44,6 +93,12 @@ int sh_interactive(void)
 		}
 
 		struct command *command = sh_parse(ed.cur->buf);
+		if (errno == SIGINT) {
+			if (got_sigwinch) {
+				sh_getwinsize();
+			}
+		}
+
 		if (command) {
 			sh_execute(command);
 			sh_freecmd(command);
-- 
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