/*	$NetBSD: slave.c,v 1.17 2021/06/13 12:46:01 rillig Exp $	*/

/*-
 * Copyright 2009 Brett Lymn <blymn@NetBSD.org>
 * Copyright 2021 Roland Illig <rillig@NetBSD.org>
 *
 * All rights reserved.
 *
 * This code has been donated to The NetBSD Foundation by the Author.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <err.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curses.h>
#include "returns.h"
#include "slave.h"

int from_director;
int to_director;
int initdone = 0;

#if 0
static const char *returns_enum_names[] = {
	"unused", "numeric", "string", "byte", "ERR", "OK", "NULL", "not NULL",
	"variable"
};
#endif

static bool
try_read_from_director(void *data, size_t n)
{
	ssize_t nread = read(from_director, data, n);
	if (nread < 0)
		err(2, "error reading from command pipe");
	if (nread == 0)
		return false;
	if ((size_t)nread != n)
		errx(2, "short read from command pipe: expected %zu, got %zu",
		    n, (size_t)nread);
	return true;
}

static void
read_from_director(void *data, size_t n)
{
	ssize_t nread = read(from_director, data, n);
	if (nread < 0)
		err(2, "error reading from command pipe");
	if ((size_t)nread != n)
		errx(2, "short read from command pipe: expected %zu, got %zu",
		    n, (size_t)nread);
}

static bool
read_command_argument(char ***pargs, int argslen)
{
	int type, len;
	char **args = *pargs;

	read_from_director(&type, sizeof(type));
	read_from_director(&len, sizeof(len));
	if (len < 0)
		return false;

	args = realloc(args, (argslen + 1) * sizeof(args[0]));
	if (args == NULL)
		err(1, "slave realloc of args array failed");
	*pargs = args;

	if (type != data_null) {
		args[argslen] = malloc(len + 1);

		if (args[argslen] == NULL)
			err(1, "slave alloc of %d bytes for args failed", len);
	}

	if (len == 0) {
		if (type == data_null)
			args[argslen] = NULL;
		else
			args[argslen][0] = '\0';
	} else {
		read_from_director(args[argslen], len);
		if (type != data_byte)
			args[argslen][len] = '\0';

		if (len == 6 && strcmp(args[argslen], "STDSCR") == 0) {
			char *stdscr_buf;
			if (asprintf(&stdscr_buf, "%p", stdscr) < 0)
				err(2, "asprintf of stdscr failed");
			free(args[argslen]);
			args[argslen] = stdscr_buf;
		}
	}
	return true;
}

/*
 * Read the command pipe for the function to execute, gather the args
 * and then process the command.
 */
static void
process_commands(void)
{
	int len, maxlen, argslen, i, type;
	char *cmdbuf, *tmpbuf, **args;

	len = maxlen = 30;
	if ((cmdbuf = malloc(maxlen)) == NULL)
		err(1, "slave cmdbuf malloc failed");

	while (try_read_from_director(&type, sizeof(type))) {
		if (type != data_string)
			errx(1, "Unexpected type for command, got %d", type);

		read_from_director(&len, sizeof(len));

		if ((len + 1) > maxlen) {
			maxlen = len + 1;
			if ((tmpbuf = realloc(cmdbuf, maxlen)) == NULL)
				err(1, "slave cmdbuf realloc to %d "
				    "bytes failed", maxlen);
			cmdbuf = tmpbuf;
		}

		read_from_director(cmdbuf, len);
		cmdbuf[len] = '\0';
		argslen = 0;
		args = NULL;

		while (read_command_argument(&args, argslen))
			argslen++;

		command_execute(cmdbuf, argslen, args);

		if (args != NULL) {
			for (i = 0; i < argslen; i++)
				free(args[i]);

			free(args);
		}
	}
}

int
main(int argc, char *argv[])
{
	if (argc != 3) {
		fprintf(stderr, "usage: %s <in_fd> <out_fd>\n", getprogname());
		return 0;
	}
	sscanf(argv[1], "%d", &from_director);
	sscanf(argv[2], "%d", &to_director);

	process_commands();

	return 0;
}