lib: add terminal resize capabilities

This adds a new size() global, which actually lives on the process.term for
each process.  One or both dimensions can be changed at a time, or both
arguments can be omitted to return the current size.

lib/core/porch_lua.c

@@ -663,6 +663,7 @@ porchlua_process_term_set(porch_ipc_t ipc __unused, struct porch_ipc_msg *msg,
 
 	memcpy(parent_termios, child_termios, sizeof(*child_termios));
 	term->initialized = true;
+	term->winsz_valid = false;
 
 	return (0);
 }

lib/core/porch_tty.c

@@ -319,10 +319,76 @@ porchlua_term_update(lua_State *L)
 	return (2);
 }
 
+static int
+porchlua_term_size(lua_State *L)
+{
+	struct porch_term *self;
+	lua_Number val;
+	bool fetching;
+
+	self = luaL_checkudata(L, 1, ORCHLUA_TERMHANDLE);
+	if (!self->winsz_valid) {
+		if (ioctl(self->proc->termctl, TIOCGWINSZ, &self->winsz) != 0) {
+			int error = errno;
+
+			luaL_pushfail(L);
+			lua_pushstring(L, strerror(error));
+			return (2);
+		}
+
+		self->winsz_valid = true;
+	}
+
+	/*
+	 * If size doesn't have both width and height arguments, it simply
+	 * return the current size.
+	 */
+	fetching = lua_isnoneornil(L, 2) && lua_isnoneornil(L, 3);
+	if (!fetching) {
+			if (!lua_isnoneornil(L, 2)) {
+				val = luaL_checknumber(L, 2);
+				if (val < 0 || val > USHRT_MAX) {
+					luaL_pushfail(L);
+					lua_pushfstring(L, "width out of bounds: %llu\n",
+					    (uint64_t)val);
+					return (2);
+				}
+
+				self->winsz.ws_col = val;
+			}
+
+			if (!lua_isnoneornil(L, 3)) {
+				val = luaL_checknumber(L, 3);
+				if (val < 0 || val > USHRT_MAX) {
+					luaL_pushfail(L);
+					lua_pushfstring(L, "height out of bounds: %llu\n",
+					    (uint64_t)val);
+					return (2);
+				}
+
+				self->winsz.ws_row = val;
+			}
+
+			if (ioctl(self->proc->termctl, TIOCSWINSZ, &self->winsz) != 0) {
+				int error = errno;
+
+				luaL_pushfail(L);
+				lua_pushstring(L, strerror(error));
+				return (2);
+			}
+	}
+
+	lua_pushnumber(L, self->winsz.ws_col);
+	lua_pushnumber(L, self->winsz.ws_row);
+
+	return (2);
+}
+
 #define	ORCHTERM_SIMPLE(n) { #n, porchlua_term_ ## n }
 static const luaL_Reg porchlua_term[] = {
 	ORCHTERM_SIMPLE(fetch),
 	ORCHTERM_SIMPLE(update),
+	ORCHTERM_SIMPLE(size),
 	{ NULL, NULL },
 };
 

lib/porch/scripter.lua

@@ -376,6 +376,12 @@ function scripter.env.matcher(val)
 	return true
 end
 
+function scripter.env.size(w, h)
+	local current_process = current_ctx.process
+
+	return current_process.term:size(w, h)
+end
+
 function scripter.env.timeout(val)
 	if val == nil or val < 0 then
 		error("Timeout must be >= 0")

lib/porch_lib.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <sys/types.h>
+#include <sys/ioctl.h>
 
 #include <stdbool.h>
 #include <termios.h>
@@ -53,8 +54,10 @@ struct porch_process {
 
 struct porch_term {
 	struct termios		term;
+	struct winsize		winsz;
 	struct porch_process	*proc;
 	bool			initialized;
+	bool			winsz_valid;
 };
 
 struct porchlua_tty_cntrl {

man/orch.5

@@ -3,7 +3,7 @@
 .\"
 .\" SPDX-License-Identifier: BSD-2-Clause
 .\"
-.Dd February 10, 2024
+.Dd September 19, 2024
 .Dt ORCH 5
 .Os
 .Sh NAME
@@ -236,6 +236,25 @@ table's keys correspond to supported characters, e.g.,
 and the associated values are all truthy to indicate that they are supported.
 .Pp
 This directive is enqueued, not processed immediately.
+.It Fn size "width" "height"
+Set or get the size of the terminal associated with the process.
+If at least one of
+.Fa width
+or
+.Fa height
+are not nil, then
+.Fn size
+will resize that dimension of the window.
+The new current size of the window is always returned.
+.Pp
+The window will start off on a fresh spawn with a width and height of 0.
+The size of the window is never persisted across processes.
+.Pp
+This directive is always processed immediately, and thus should always be used
+in either an
+.Fn enqueue
+or
+fail context.
 .It Fn raw "boolean"
 Changes the raw
 .Fn write

tests/resize_basic.orch

@@ -0,0 +1,30 @@
+spawn("resized.sh")
+match "ready"
+
+enqueue(function()
+	local w, h = assert(size())
+
+	-- pty sizes start at 0 when we spawn off.
+	assert(w == 0, "width is wrong, expected 0 got " .. w)
+	assert(h == 0, "height is wrong, expected 0 got " .. h)
+
+	w, h = size(w + 25, h + 80)
+
+	-- Make sure that it's returning the *new* width and height when we set
+	-- them.
+	assert(w == 25, "width is wrong, expected 25 got " .. w)
+	assert(h == 80, "height is wrong, expected 80 got " .. h)
+
+	-- And not setting anything should still return the current dimensions.
+	w, h = size()
+	assert(w == 25, "width is wrong, expected 25 got " .. w)
+	assert(h == 80, "height is wrong, expected 80 got " .. h)
+	w, h = size(nil, nil)
+	assert(w == 25, "width is wrong, expected 25 got " .. w)
+	assert(h == 80, "height is wrong, expected 80 got " .. h)
+end)
+
+match "resized"
+write "^C"
+
+match "1"

tests/resize_optional.orch

@@ -0,0 +1,25 @@
+spawn("resized.sh")
+match "ready"
+
+enqueue(function()
+	local w, h = assert(size())
+
+	assert(w == 0, "width is wrong, expected 0 got " .. w)
+	assert(h == 0, "height is wrong, expected 0 got " .. h)
+
+	w, h = size(nil, h + 80)
+
+	assert(w == 0, "width is wrong, expected 0 got " .. w)
+	assert(h == 80, "height is wrong, expected 80 got " .. h)
+end)
+
+match "resized"
+
+enqueue(function()
+	local w, h = size(25)
+	assert(w == 25, "width is wrong, expected 25 got " .. w)
+	assert(h == 80, "height is wrong, expected 80 got " .. h)
+end)
+
+write "^C"
+match "2"

tests/resized.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+loop=1
+
+trap 'echo resized; caught=$((caught + 1))' WINCH
+trap 'loop=0' INT
+
+# Release the hounds now that the signal handler is setup.
+echo "ready"
+
+caught=0
+
+while [ "$loop" -ne 0 ]; do
+	sleep 1
+done
+
+if [ "$caught" -eq 0 ]; then
+	1>&2 echo "Did not observe SIGWINCH"
+	exit 1
+fi
+
+echo "$caught"