view rvinterf/libasync/interf.c @ 465:003e48f8ebe1

rvinterf/etmsync/fsnew.c: cast 0 to (char *) for execl sentinel I generally don't use NULL and use plain 0 instead, based on a "NULL considered harmful" discussion on the classiccmp mailing list many aeons ago (I couldn't find it, and I reason that it must have been 2005 or earlier), but a recent complaint by a packager sent me searching, and I found this: https://ewontfix.com/11/ While I don't give a @#$% about "modern" systems and code-nazi tools, I realized that passing a plain 0 as a pointer sentinel in execl is wrong because it will break on systems where pointers are longer than the plain int type. Again, I don't give a @#$% about the abomination of x86_64 and the like, but if anyone ever manages to port my code to something like a PDP-11 (16-bit int, 32-bit long and pointers), then passing a plain 0 as a function argument where a pointer is expected most definitely won't work: if the most natural stack slot and SP alignment unit is 16 bits, fitting an int, with longs and pointers taking up two such slots, then the call stack will be totally wrong with a plain 0 passed for a pointer. Casting the 0 to (char *) ought to be the most kosher solution for the most retro systems possible.
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 11 Feb 2019 00:00:19 +0000
parents 09b4fd9b3827
children
line wrap: on
line source

/*
 * This module implements the link to rvinterf.
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "localsock.h"
#include "exitcodes.h"

extern int sock;

u_char rvi_msg[LOCALSOCK_MAX_MSG];
int rvi_msg_len;

static int rx_state, rx_left;
static u_char *rx_ptr;

void
localsock_prep_for_length_rx()
{
	rx_state = 0;
	rx_ptr = rvi_msg;
	rx_left = 2;
}

static void
prep_for_message_rx()
{
	rx_state = 1;
	rx_ptr = rvi_msg;
	rx_left = rvi_msg_len;
}

void
process_msg_from_rvinterf()
{
	switch (rvi_msg[0]) {
	case RVI2CLI_PKT_FROM_TARGET:
		process_pkt_from_target();
		return;
	case RVI2CLI_LOCAL_CMD_RESP:
		if (rvi_msg_len < 2)
			goto bad;
		if (rvi_msg[1] == '+')
			return;
		tty_cleanup();
		fprintf(stderr, "Error from rvinterf: %.*s\n", rvi_msg_len - 1,
			rvi_msg + 1);
		exit(ERROR_RVINTERF);
	default:
	bad:
		tty_cleanup();
		fprintf(stderr,
			"Error: unexpected message type %02X from rvinterf\n",
			rvi_msg[0]);
		exit(ERROR_RVINTERF);
	}
}

void
handle_rvinterf_input()
{
	int cc;

	cc = read(sock, rx_ptr, rx_left);
	if (cc <= 0) {
		tty_cleanup();
		perror("read from rvinterf socket");
		exit(ERROR_RVINTERF);
	}
	rx_ptr += cc;
	rx_left -= cc;
	if (rx_left)
		return;
	/* got the thing, process it */
	if (rx_state) {
		process_msg_from_rvinterf();
		localsock_prep_for_length_rx();
	} else {
		rvi_msg_len = rvi_msg[0] << 8 | rvi_msg[1];
		if (rvi_msg_len < 1 || rvi_msg_len > LOCALSOCK_MAX_MSG) {
			tty_cleanup();
			fprintf(stderr,
				"Invalid length from rvinterf: %02X%02X\n",
				rvi_msg[0], rvi_msg[1]);
			exit(ERROR_RVINTERF);
		}
		prep_for_message_rx();
	}
}

void
send_pkt_to_target(pkt, pktlen)
	u_char *pkt;
{
	u_char hdrbuf[3];
	int len1;

	len1 = pktlen + 1;
	hdrbuf[0] = len1 >> 8;
	hdrbuf[1] = len1 & 0xFF;
	hdrbuf[2] = CLI2RVI_PKT_TO_TARGET;
	write(sock, hdrbuf, 3);
	write(sock, pkt, pktlen);
}