/*      $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;
}