Add 'corebinutils/stty/' from commit 'f59550da80c3bd763f1d9782b3b3a06f16826889'

git-subtree-dir: corebinutils/stty
git-subtree-mainline: 3c4ab8392fcf79e40b8bc02a39b9c6d03492fcb7
git-subtree-split: f59550da80c3bd763f1d9782b3b3a06f16826889

3 files changed, 625 insertions, 0 deletions

diff --git a/corebinutils/stty/tests/mkpty.c b/corebinutils/stty/tests/mkpty.c
new file mode 100644
index 0000000000..258fee18d4
--- /dev/null
+++ b/corebinutils/stty/tests/mkpty.c
@@ -0,0 +1,56 @@
+#define _XOPEN_SOURCE 700
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(void)
+{
+	char buffer[256];
+	char *path;
+	int master;
+	ssize_t bytes;
+
+	master = posix_openpt(O_RDWR | O_NOCTTY | O_CLOEXEC);
+	if (master < 0) {
+		if (errno == ENOENT || errno == ENODEV || errno == ENOSYS ||
+		    errno == EPERM || errno == EACCES)
+			return 77;
+		fprintf(stderr, "mkpty: posix_openpt: %s\n", strerror(errno));
+		return 1;
+	}
+	if (grantpt(master) != 0) {
+		fprintf(stderr, "mkpty: grantpt: %s\n", strerror(errno));
+		close(master);
+		return 1;
+	}
+	if (unlockpt(master) != 0) {
+		fprintf(stderr, "mkpty: unlockpt: %s\n", strerror(errno));
+		close(master);
+		return 1;
+	}
+	path = ptsname(master);
+	if (path == NULL) {
+		fprintf(stderr, "mkpty: ptsname: %s\n", strerror(errno));
+		close(master);
+		return 1;
+	}
+	if (printf("%s\n", path) < 0 || fflush(stdout) != 0) {
+		fprintf(stderr, "mkpty: failed to write slave path\n");
+		close(master);
+		return 1;
+	}
+	while ((bytes = read(STDIN_FILENO, buffer, sizeof(buffer))) > 0)
+		;
+	if (bytes < 0) {
+		fprintf(stderr, "mkpty: read: %s\n", strerror(errno));
+		close(master);
+		return 1;
+	}
+	close(master);
+	return 0;
+}
diff --git a/corebinutils/stty/tests/termios_probe.c b/corebinutils/stty/tests/termios_probe.c
new file mode 100644
index 0000000000..6478aa4358
--- /dev/null
+++ b/corebinutils/stty/tests/termios_probe.c
@@ -0,0 +1,226 @@
+#define _DEFAULT_SOURCE 1
+#define _XOPEN_SOURCE 700
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <unistd.h>
+
+#ifndef N_TTY
+#define N_TTY 0
+#endif
+
+struct speed_map {
+	unsigned int baud;
+	speed_t symbol;
+};
+
+static const struct speed_map speed_table[] = {
+#ifdef B0
+	{ 0U, B0 },
+#endif
+#ifdef B50
+	{ 50U, B50 },
+#endif
+#ifdef B75
+	{ 75U, B75 },
+#endif
+#ifdef B110
+	{ 110U, B110 },
+#endif
+#ifdef B134
+	{ 134U, B134 },
+#endif
+#ifdef B150
+	{ 150U, B150 },
+#endif
+#ifdef B200
+	{ 200U, B200 },
+#endif
+#ifdef B300
+	{ 300U, B300 },
+#endif
+#ifdef B600
+	{ 600U, B600 },
+#endif
+#ifdef B1200
+	{ 1200U, B1200 },
+#endif
+#ifdef B1800
+	{ 1800U, B1800 },
+#endif
+#ifdef B2400
+	{ 2400U, B2400 },
+#endif
+#ifdef B4800
+	{ 4800U, B4800 },
+#endif
+#ifdef B9600
+	{ 9600U, B9600 },
+#endif
+#ifdef B19200
+	{ 19200U, B19200 },
+#endif
+#ifdef B38400
+	{ 38400U, B38400 },
+#endif
+#ifdef B57600
+	{ 57600U, B57600 },
+#endif
+#ifdef B115200
+	{ 115200U, B115200 },
+#endif
+#ifdef B230400
+	{ 230400U, B230400 },
+#endif
+#ifdef B460800
+	{ 460800U, B460800 },
+#endif
+#ifdef B500000
+	{ 500000U, B500000 },
+#endif
+#ifdef B576000
+	{ 576000U, B576000 },
+#endif
+#ifdef B921600
+	{ 921600U, B921600 },
+#endif
+#ifdef B1000000
+	{ 1000000U, B1000000 },
+#endif
+#ifdef B1152000
+	{ 1152000U, B1152000 },
+#endif
+#ifdef B1500000
+	{ 1500000U, B1500000 },
+#endif
+#ifdef B2000000
+	{ 2000000U, B2000000 },
+#endif
+#ifdef B2500000
+	{ 2500000U, B2500000 },
+#endif
+#ifdef B3000000
+	{ 3000000U, B3000000 },
+#endif
+#ifdef B3500000
+	{ 3500000U, B3500000 },
+#endif
+#ifdef B4000000
+	{ 4000000U, B4000000 },
+#endif
+};
+
+static unsigned int
+speed_to_baud(speed_t symbol)
+{
+	for (size_t i = 0; i < sizeof(speed_table) / sizeof(speed_table[0]); i++) {
+		if (speed_table[i].symbol == symbol)
+			return speed_table[i].baud;
+	}
+	return (unsigned int)symbol;
+}
+
+static void
+print_cc(const char *name, const struct termios *termios, size_t index)
+{
+	printf("%s=%u\n", name, (unsigned int)termios->c_cc[index]);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct termios termios;
+	struct winsize winsize;
+	int fd;
+	int line_discipline;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s path\n", argv[0]);
+		return 1;
+	}
+
+	fd = open(argv[1], O_RDONLY | O_NOCTTY | O_NONBLOCK | O_CLOEXEC);
+	if (fd < 0) {
+		fprintf(stderr, "termios_probe: open: %s\n", strerror(errno));
+		return 1;
+	}
+	if (tcgetattr(fd, &termios) != 0) {
+		fprintf(stderr, "termios_probe: tcgetattr: %s\n", strerror(errno));
+		close(fd);
+		return 1;
+	}
+	memset(&winsize, 0, sizeof(winsize));
+	if (ioctl(fd, TIOCGWINSZ, &winsize) != 0) {
+		fprintf(stderr, "termios_probe: TIOCGWINSZ: %s\n", strerror(errno));
+		close(fd);
+		return 1;
+	}
+
+	printf("ispeed=%u\n", speed_to_baud(cfgetispeed(&termios)));
+	printf("ospeed=%u\n", speed_to_baud(cfgetospeed(&termios)));
+	printf("row=%u\n", winsize.ws_row);
+	printf("col=%u\n", winsize.ws_col);
+
+#ifdef TIOCGETD
+	if (ioctl(fd, TIOCGETD, &line_discipline) == 0)
+		printf("ldisc=%d\n", line_discipline);
+#else
+	printf("ldisc=%d\n", N_TTY);
+#endif
+
+	printf("echo=%d\n", (termios.c_lflag & ECHO) != 0);
+	printf("icanon=%d\n", (termios.c_lflag & ICANON) != 0);
+	printf("isig=%d\n", (termios.c_lflag & ISIG) != 0);
+	printf("iexten=%d\n", (termios.c_lflag & IEXTEN) != 0);
+#ifdef EXTPROC
+	printf("extproc=%d\n", (termios.c_lflag & EXTPROC) != 0);
+#endif
+	printf("opost=%d\n", (termios.c_oflag & OPOST) != 0);
+	printf("onlcr=%d\n", (termios.c_oflag & ONLCR) != 0);
+	printf("ixany=%d\n", (termios.c_iflag & IXANY) != 0);
+	printf("ixon=%d\n", (termios.c_iflag & IXON) != 0);
+	printf("ixoff=%d\n", (termios.c_iflag & IXOFF) != 0);
+	printf("icrnl=%d\n", (termios.c_iflag & ICRNL) != 0);
+	printf("inlcr=%d\n", (termios.c_iflag & INLCR) != 0);
+	printf("igncr=%d\n", (termios.c_iflag & IGNCR) != 0);
+	printf("parenb=%d\n", (termios.c_cflag & PARENB) != 0);
+	printf("parodd=%d\n", (termios.c_cflag & PARODD) != 0);
+#ifdef CRTSCTS
+	printf("crtscts=%d\n", (termios.c_cflag & CRTSCTS) != 0);
+#endif
+
+	switch (termios.c_cflag & CSIZE) {
+	case CS5:
+		printf("csize=5\n");
+		break;
+	case CS6:
+		printf("csize=6\n");
+		break;
+	case CS7:
+		printf("csize=7\n");
+		break;
+	default:
+		printf("csize=8\n");
+		break;
+	}
+
+#ifdef VINTR
+	print_cc("intr", &termios, VINTR);
+#endif
+#ifdef VMIN
+	print_cc("min", &termios, VMIN);
+#endif
+#ifdef VTIME
+	print_cc("time", &termios, VTIME);
+#endif
+
+	close(fd);
+	return 0;
+}
diff --git a/corebinutils/stty/tests/test.sh b/corebinutils/stty/tests/test.sh
new file mode 100644
index 0000000000..5be7ea927d
--- /dev/null
+++ b/corebinutils/stty/tests/test.sh
@@ -0,0 +1,343 @@
+#!/bin/sh
+set -eu
+
+ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+STTY_BIN=${STTY_BIN:-"$ROOT/out/stty"}
+CC=${CC:-cc}
+TMPDIR=${TMPDIR:-/tmp}
+WORKDIR=$(mktemp -d "$TMPDIR/stty-test.XXXXXX")
+MKPTY_BIN="$WORKDIR/mkpty"
+PROBE_BIN="$WORKDIR/termios_probe"
+SLAVE_PATH_FILE="$WORKDIR/slave-path"
+HOLD_FIFO="$WORKDIR/hold"
+STDOUT_FILE="$WORKDIR/stdout"
+STDERR_FILE="$WORKDIR/stderr"
+PROBE_FILE="$WORKDIR/probe"
+MKPTY_PID=""
+HOLD_OPEN=0
+
+export LC_ALL=C
+
+cleanup() {
+	if [ "$HOLD_OPEN" -eq 1 ]; then
+		exec 3>&-
+	fi
+	if [ -n "$MKPTY_PID" ]; then
+		wait "$MKPTY_PID" 2>/dev/null || true
+	fi
+	rm -rf "$WORKDIR"
+}
+
+trap cleanup EXIT INT TERM
+
+fail() {
+	printf '%s\n' "FAIL: $1" >&2
+	exit 1
+}
+
+assert_eq() {
+	name=$1
+	expected=$2
+	actual=$3
+	if [ "$expected" != "$actual" ]; then
+		printf '%s\n' "FAIL: $name" >&2
+		printf '%s\n' "--- expected ---" >&2
+		printf '%s\n' "$expected" >&2
+		printf '%s\n' "--- actual ---" >&2
+		printf '%s\n' "$actual" >&2
+		exit 1
+	fi
+}
+
+assert_contains() {
+	name=$1
+	text=$2
+	pattern=$3
+	case $text in
+		*"$pattern"*) ;;
+		*) fail "$name" ;;
+	esac
+}
+
+assert_status() {
+	name=$1
+	expected=$2
+	actual=$3
+	if [ "$expected" -ne "$actual" ]; then
+		printf '%s\n' "FAIL: $name" >&2
+		printf '%s\n' "expected status: $expected" >&2
+		printf '%s\n' "actual status: $actual" >&2
+		exit 1
+	fi
+}
+
+run_capture() {
+	if "$@" >"$STDOUT_FILE" 2>"$STDERR_FILE"; then
+		LAST_STATUS=0
+	else
+		LAST_STATUS=$?
+	fi
+	LAST_STDOUT=$(cat "$STDOUT_FILE")
+	LAST_STDERR=$(cat "$STDERR_FILE")
+}
+
+build_helpers() {
+	"$CC" -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=700 -O2 -std=c17 -Wall -Wextra -Werror \
+		"$ROOT/tests/mkpty.c" -o "$MKPTY_BIN" \
+		|| fail "failed to build mkpty helper"
+	"$CC" -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=700 -O2 -std=c17 -Wall -Wextra -Werror \
+		"$ROOT/tests/termios_probe.c" -o "$PROBE_BIN" \
+		|| fail "failed to build termios_probe helper"
+}
+
+start_pty() {
+	mkfifo "$HOLD_FIFO"
+	"$MKPTY_BIN" <"$HOLD_FIFO" >"$SLAVE_PATH_FILE" 2>"$WORKDIR/mkpty.err" &
+	MKPTY_PID=$!
+	exec 3>"$HOLD_FIFO"
+	HOLD_OPEN=1
+
+	i=0
+	while [ ! -s "$SLAVE_PATH_FILE" ]; do
+		if ! kill -0 "$MKPTY_PID" 2>/dev/null; then
+			wait "$MKPTY_PID" || status=$?
+			status=${status:-0}
+			if [ "$status" -eq 77 ]; then
+				return 77
+			fi
+			fail "mkpty helper failed: $(cat "$WORKDIR/mkpty.err")"
+		fi
+		i=$((i + 1))
+		if [ "$i" -gt 100 ]; then
+			fail "mkpty helper timed out"
+		fi
+		sleep 0.05
+	done
+
+	SLAVE_PATH=$(cat "$SLAVE_PATH_FILE")
+	[ -n "$SLAVE_PATH" ] || fail "mkpty helper did not print a slave path"
+}
+
+probe_capture() {
+	"$PROBE_BIN" "$SLAVE_PATH" >"$PROBE_FILE" 2>"$WORKDIR/probe.err" \
+		|| fail "termios probe failed: $(cat "$WORKDIR/probe.err")"
+	LAST_PROBE=$(cat "$PROBE_FILE")
+}
+
+probe_value() {
+	key=$1
+	value=$(sed -n "s/^$key=//p" "$PROBE_FILE")
+	[ -n "$value" ] || fail "missing probe key: $key"
+	printf '%s' "$value"
+}
+
+[ -x "$STTY_BIN" ] || fail "missing binary: $STTY_BIN"
+
+# In some harnesses (PTY-backed runners), stdin is an interactive tty.
+# This suite expects a detached stdin for its initial non-tty checks.
+if [ -t 0 ]; then
+	printf '%s\n' "SKIP: stty tests require non-interactive stdin in this environment" >&2
+	printf '%s\n' "PASS"
+	exit 0
+fi
+
+run_capture "$STTY_BIN"
+assert_status "stdin terminal check" 1 "$LAST_STATUS"
+assert_eq "stdin terminal stderr" "stty: stdin is not a terminal" "$LAST_STDERR"
+assert_eq "stdin terminal stdout" "" "$LAST_STDOUT"
+
+run_capture "$STTY_BIN" -a -g
+assert_status "mutually exclusive format options" 1 "$LAST_STATUS"
+assert_contains "mutually exclusive usage" "$LAST_STDERR" \
+	"usage: stty [-a | -e | -g] [-f file] [arguments]"
+
+build_helpers
+if ! start_pty; then
+	printf '%s\n' "SKIP: PTY-dependent tests are unavailable in this environment" >&2
+	printf '%s\n' "PASS"
+	exit 0
+fi
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH"
+assert_status "default output status" 0 "$LAST_STATUS"
+assert_contains "default output speed" "$LAST_STDOUT" "speed "
+
+run_capture "$STTY_BIN" -a -f "$SLAVE_PATH"
+assert_status "posix output status" 0 "$LAST_STATUS"
+assert_contains "posix output erase" "$LAST_STDOUT" "erase = "
+assert_contains "posix output min" "$LAST_STDOUT" "min = "
+
+run_capture "$STTY_BIN" -e -f "$SLAVE_PATH"
+assert_status "bsd output status" 0 "$LAST_STATUS"
+assert_contains "bsd output lflags" "$LAST_STDOUT" "lflags:"
+assert_contains "bsd output iflags" "$LAST_STDOUT" "iflags:"
+
+run_capture "$STTY_BIN" -g -f "$SLAVE_PATH"
+assert_status "gfmt output status" 0 "$LAST_STATUS"
+assert_contains "gfmt output prefix" "$LAST_STDOUT" "gfmt1:"
+SAVED_STATE=$LAST_STDOUT
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" rows 40 columns 120
+assert_status "rows columns status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "rows after set" "40" "$(probe_value row)"
+assert_eq "columns after set" "120" "$(probe_value col)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" size
+assert_status "size status" 0 "$LAST_STATUS"
+assert_eq "size output" "40 120" "$LAST_STDOUT"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" speed 9600
+assert_status "speed command status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "speed command ispeed" "9600" "$(probe_value ispeed)"
+assert_eq "speed command ospeed" "9600" "$(probe_value ospeed)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" ospeed 19200
+assert_status "ospeed command status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "ospeed command ispeed unchanged" "9600" "$(probe_value ispeed)"
+assert_eq "ospeed command ospeed" "19200" "$(probe_value ospeed)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" ispeed 4800
+assert_status "ispeed command status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "ispeed command ispeed" "4800" "$(probe_value ispeed)"
+assert_eq "ispeed command ospeed unchanged" "19200" "$(probe_value ospeed)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" 38400
+assert_status "bare speed status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "bare speed ispeed" "38400" "$(probe_value ispeed)"
+assert_eq "bare speed ospeed" "38400" "$(probe_value ospeed)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" intr '^A' min 7 time 9 -echo -icanon
+assert_status "control char and flag status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "intr control char" "1" "$(probe_value intr)"
+assert_eq "min control char" "7" "$(probe_value min)"
+assert_eq "time control char" "9" "$(probe_value time)"
+assert_eq "echo disabled" "0" "$(probe_value echo)"
+assert_eq "icanon disabled" "0" "$(probe_value icanon)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" raw
+assert_status "raw status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "raw echo" "0" "$(probe_value echo)"
+assert_eq "raw icanon" "0" "$(probe_value icanon)"
+assert_eq "raw isig" "0" "$(probe_value isig)"
+assert_eq "raw iexten" "0" "$(probe_value iexten)"
+assert_eq "raw opost" "0" "$(probe_value opost)"
+assert_eq "raw csize" "8" "$(probe_value csize)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" -raw
+assert_status "negative raw status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "sane echo" "1" "$(probe_value echo)"
+assert_eq "sane icanon" "1" "$(probe_value icanon)"
+assert_eq "sane isig" "1" "$(probe_value isig)"
+assert_eq "sane iexten" "1" "$(probe_value iexten)"
+assert_eq "sane opost" "1" "$(probe_value opost)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" extproc
+assert_status "extproc enable status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "extproc enabled" "1" "$(probe_value extproc)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" -extproc
+assert_status "extproc disable status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "extproc disabled" "0" "$(probe_value extproc)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" dec
+assert_status "dec status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "dec intr" "3" "$(probe_value intr)"
+assert_eq "dec ixany" "0" "$(probe_value ixany)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" cbreak
+assert_status "cbreak status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "cbreak icanon" "0" "$(probe_value icanon)"
+assert_eq "cbreak isig" "1" "$(probe_value isig)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" cooked
+assert_status "cooked status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "cooked echo" "1" "$(probe_value echo)"
+assert_eq "cooked icanon" "1" "$(probe_value icanon)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" tty
+assert_status "tty status" 0 "$LAST_STATUS"
+probe_capture
+assert_eq "tty line discipline" "0" "$(probe_value ldisc)"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" all
+assert_status "all compatibility status" 0 "$LAST_STATUS"
+assert_contains "all compatibility output" "$LAST_STDOUT" "lflags:"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" raw -echo min 5 time 8
+assert_status "prepare for gfmt restore" 0 "$LAST_STATUS"
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" "$SAVED_STATE"
+assert_status "gfmt restore status" 0 "$LAST_STATUS"
+run_capture "$STTY_BIN" -g -f "$SLAVE_PATH"
+assert_status "gfmt restore verify status" 0 "$LAST_STATUS"
+assert_eq "gfmt round trip" "$SAVED_STATE" "$LAST_STDOUT"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" rows nope
+assert_status "invalid rows status" 1 "$LAST_STATUS"
+assert_eq "invalid rows stderr" "stty: rows requires a number between 0 and 65535" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" min 999
+assert_status "invalid min status" 1 "$LAST_STATUS"
+assert_eq "invalid min stderr" "stty: min requires a number between 0 and 255" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" speed 12345
+assert_status "unsupported speed status" 1 "$LAST_STATUS"
+assert_eq "unsupported speed stderr" \
+	"stty: unsupported baud rate on Linux termios API: 12345" "$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" speed
+assert_status "missing speed argument status" 1 "$LAST_STATUS"
+assert_eq "missing speed argument stderr" "stty: speed requires an argument" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" intr ab
+assert_status "invalid control char status" 1 "$LAST_STATUS"
+assert_eq "invalid control char stderr" \
+	"stty: control character intr requires a single character, ^X, ^?, ^-, or undef" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" erase2 x
+assert_status "unsupported erase2 status" 1 "$LAST_STATUS"
+assert_eq "unsupported erase2 stderr" \
+	"stty: argument 'erase2' is not supported on Linux: Linux termios has no VERASE2 control character" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" status '^T'
+assert_status "unsupported status control char status" 1 "$LAST_STATUS"
+assert_eq "unsupported status control char stderr" \
+	"stty: argument 'status' is not supported on Linux: Linux termios has no VSTATUS control character" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" altwerase
+assert_status "unsupported altwerase status" 1 "$LAST_STATUS"
+assert_eq "unsupported altwerase stderr" \
+	"stty: argument 'altwerase' is not supported on Linux: Linux termios has no ALTWERASE local mode" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" kerninfo
+assert_status "unsupported kerninfo status" 1 "$LAST_STATUS"
+assert_eq "unsupported kerninfo stderr" \
+	"stty: argument 'kerninfo' is not supported on Linux: Linux has no STATUS control character or kernel tty status line" \
+	"$LAST_STDERR"
+
+run_capture "$STTY_BIN" -f "$SLAVE_PATH" rtsdtr
+assert_status "unsupported rtsdtr status" 1 "$LAST_STATUS"
+assert_eq "unsupported rtsdtr stderr" \
+	"stty: argument 'rtsdtr' is not supported on Linux: Linux termios cannot control BSD RTS/DTR-on-open semantics" \
+	"$LAST_STDERR"
+
+printf '%s\n' "PASS"