Add getty(8).

utils/.gitignore

@@ -21,6 +21,7 @@ expr
 false
 find
 getaddrinfo
+getty
 halt
 head
 help

utils/Makefile

@@ -93,6 +93,7 @@ uname.1 \
 
 SBINS=\
 chroot \
+getty \
 unmount \
 
 MANPAGES8=\

utils/getty.c

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2023 Jonas 'Sortie' Termansen.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF7
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * getty.c
+ * Initialize a terminal session.
+ */
+
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+
+#include <brand.h>
+#include <err.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char* argv[])
+{
+	bool logo = true;
+	struct winsize ws;
+	ws.ws_row = 24;
+	ws.ws_col = 80;
+	int opt;
+	while ( (opt = getopt(argc, argv, "h:lw:")) != -1 )
+	{
+		switch ( opt )
+		{
+		case 'l': logo = true; break;
+		case 'h': ws.ws_row = atoi(optarg); break;
+		case 'w': ws.ws_col = atoi(optarg); break;
+		default: return 1;
+		}
+	}
+	if ( argc - optind < 1 )
+		errx(1, "Expected terminal path");
+	if ( argc - optind < 2 )
+		errx(1, "Expected program");
+	const char* path = argv[optind + 0];
+	int tty = open(path, O_RDWR);
+	if ( tty < 0 )
+		err(1, "%s", path);
+	if ( !isatty(tty) )
+		err(1, "%s", path);
+	struct termios tio;
+	if ( tcgetattr(tty, &tio) < 0 )
+		err(1, "tcgetattr: %s", path);
+	pid_t child_pid = fork();
+	if ( child_pid < 0 )
+		err(1, "fork");
+	if ( child_pid )
+	{
+		int status;
+		waitpid(child_pid, &status, 0);
+		return WEXITSTATUS(status);
+	}
+	if ( setsid() < 0 )
+		err(1, "setsid");
+	if ( ioctl(tty, TIOCSCTTY) < 0 )
+		err(1, "ioctl: TIOCSCTTY");
+	if ( close(0) < 0 || close(1) < 0 || close(2) < 0 )
+		err(1, "close");
+	if ( dup2(tty, 0) != 0 ||
+	     dup2(tty, 1) != 1 ||
+	     dup2(tty, 2) != 2 )
+		err(1, "dup");
+	if ( closefrom(3) < 0 )
+		err(1, "closefrom");
+	tty = 0;
+	if ( ioctl(tty, TIOCSWINSZ, &ws) < 0 )
+		err(1, "TIOCSWINSZ");
+	tio.c_cflag |= CREAD;
+	if ( tcsetattr(tty, TCSANOW, &tio) < 0 )
+		err(1, "tcsetattr: %s", path);
+	if ( logo )
+	{
+		printf("\e[37;41m\e[J");
+		const char* string = BRAND_LOGO;
+		while ( *string )
+		{
+			size_t string_width = strcspn(string, "\n");
+			size_t leading = string_width <= ws.ws_col ?
+				             (ws.ws_col - string_width) / 2 : 0;
+			for ( size_t i = 0; i < leading; i++ )
+				putchar(' ');
+			fwrite(string, string_width, 1, stdout);
+			string += string_width;
+			if ( *string == '\n' )
+			{
+				string++;
+				if ( !*string )
+					printf("\e[m");
+				putchar('\n');
+			}
+		}
+	}
+	execvp(argv[optind + 1], argv + optind + 1);
+	err(1, "%s", argv[optind + 1]);
+}