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      1 /*	$NetBSD: slave.c,v 1.17 2021/06/13 12:46:01 rillig Exp $	*/
      2 
      3 /*-
      4  * Copyright 2009 Brett Lymn <blymn (at) NetBSD.org>
      5  * Copyright 2021 Roland Illig <rillig (at) NetBSD.org>
      6  *
      7  * All rights reserved.
      8  *
      9  * This code has been donated to The NetBSD Foundation by the Author.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. The name of the author may not be used to endorse or promote products
     17  *    derived from this software without specific prior written permission
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include <fcntl.h>
     32 #include <sys/ioctl.h>
     33 #include <unistd.h>
     34 #include <err.h>
     35 #include <stdbool.h>
     36 #include <stdio.h>
     37 #include <stdlib.h>
     38 #include <string.h>
     39 #include <curses.h>
     40 #include "returns.h"
     41 #include "slave.h"
     42 
     43 int from_director;
     44 int to_director;
     45 int initdone = 0;
     46 
     47 #if 0
     48 static const char *returns_enum_names[] = {
     49 	"unused", "numeric", "string", "byte", "ERR", "OK", "NULL", "not NULL",
     50 	"variable"
     51 };
     52 #endif
     53 
     54 static bool
     55 try_read_from_director(void *data, size_t n)
     56 {
     57 	ssize_t nread = read(from_director, data, n);
     58 	if (nread < 0)
     59 		err(2, "error reading from command pipe");
     60 	if (nread == 0)
     61 		return false;
     62 	if ((size_t)nread != n)
     63 		errx(2, "short read from command pipe: expected %zu, got %zu",
     64 		    n, (size_t)nread);
     65 	return true;
     66 }
     67 
     68 static void
     69 read_from_director(void *data, size_t n)
     70 {
     71 	ssize_t nread = read(from_director, data, n);
     72 	if (nread < 0)
     73 		err(2, "error reading from command pipe");
     74 	if ((size_t)nread != n)
     75 		errx(2, "short read from command pipe: expected %zu, got %zu",
     76 		    n, (size_t)nread);
     77 }
     78 
     79 static bool
     80 read_command_argument(char ***pargs, int argslen)
     81 {
     82 	int type, len;
     83 	char **args = *pargs;
     84 
     85 	read_from_director(&type, sizeof(type));
     86 	read_from_director(&len, sizeof(len));
     87 	if (len < 0)
     88 		return false;
     89 
     90 	args = realloc(args, (argslen + 1) * sizeof(args[0]));
     91 	if (args == NULL)
     92 		err(1, "slave realloc of args array failed");
     93 	*pargs = args;
     94 
     95 	if (type != data_null) {
     96 		args[argslen] = malloc(len + 1);
     97 
     98 		if (args[argslen] == NULL)
     99 			err(1, "slave alloc of %d bytes for args failed", len);
    100 	}
    101 
    102 	if (len == 0) {
    103 		if (type == data_null)
    104 			args[argslen] = NULL;
    105 		else
    106 			args[argslen][0] = '\0';
    107 	} else {
    108 		read_from_director(args[argslen], len);
    109 		if (type != data_byte)
    110 			args[argslen][len] = '\0';
    111 
    112 		if (len == 6 && strcmp(args[argslen], "STDSCR") == 0) {
    113 			char *stdscr_buf;
    114 			if (asprintf(&stdscr_buf, "%p", stdscr) < 0)
    115 				err(2, "asprintf of stdscr failed");
    116 			free(args[argslen]);
    117 			args[argslen] = stdscr_buf;
    118 		}
    119 	}
    120 	return true;
    121 }
    122 
    123 /*
    124  * Read the command pipe for the function to execute, gather the args
    125  * and then process the command.
    126  */
    127 static void
    128 process_commands(void)
    129 {
    130 	int len, maxlen, argslen, i, type;
    131 	char *cmdbuf, *tmpbuf, **args;
    132 
    133 	len = maxlen = 30;
    134 	if ((cmdbuf = malloc(maxlen)) == NULL)
    135 		err(1, "slave cmdbuf malloc failed");
    136 
    137 	while (try_read_from_director(&type, sizeof(type))) {
    138 		if (type != data_string)
    139 			errx(1, "Unexpected type for command, got %d", type);
    140 
    141 		read_from_director(&len, sizeof(len));
    142 
    143 		if ((len + 1) > maxlen) {
    144 			maxlen = len + 1;
    145 			if ((tmpbuf = realloc(cmdbuf, maxlen)) == NULL)
    146 				err(1, "slave cmdbuf realloc to %d "
    147 				    "bytes failed", maxlen);
    148 			cmdbuf = tmpbuf;
    149 		}
    150 
    151 		read_from_director(cmdbuf, len);
    152 		cmdbuf[len] = '\0';
    153 		argslen = 0;
    154 		args = NULL;
    155 
    156 		while (read_command_argument(&args, argslen))
    157 			argslen++;
    158 
    159 		command_execute(cmdbuf, argslen, args);
    160 
    161 		if (args != NULL) {
    162 			for (i = 0; i < argslen; i++)
    163 				free(args[i]);
    164 
    165 			free(args);
    166 		}
    167 	}
    168 }
    169 
    170 int
    171 main(int argc, char *argv[])
    172 {
    173 	if (argc != 3) {
    174 		fprintf(stderr, "usage: %s <in_fd> <out_fd>\n", getprogname());
    175 		return 0;
    176 	}
    177 	sscanf(argv[1], "%d", &from_director);
    178 	sscanf(argv[2], "%d", &to_director);
    179 
    180 	process_commands();
    181 
    182 	return 0;
    183 }
    184