view rvinterf/asyncshell/oneshot.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 10f4062e049b
children b55a81ce7497
line wrap: on
line source

/*
 * This module implements the one-shot command mode of fc-shell.
 */

#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include "limits.h"
#include "exitcodes.h"

extern int cmd_key_oneshot();
extern int cmd_keydown_oneshot();
extern int cmd_keyup_oneshot();
extern int cmd_poweroff();
extern int cmd_send_oneshot();
extern int cmd_sp_oneshot();
extern int cmd_str_oneshot();
extern int cmd_tchdl_oneshot();
extern int cmd_tgtreset();
extern int cmd_unterm_oneshot();

static struct cmdtab {
	char *cmd;
	int minargs;
	int maxargs;
	int (*func)();
} cmdtab[] = {
	{"key", 1, 1, cmd_key_oneshot},
	{"keydown", 1, 1, cmd_keydown_oneshot},
	{"keyup", 1, 1, cmd_keyup_oneshot},
	{"poweroff", 0, 0, cmd_poweroff},
	{"send", 1, MAX_PKT_TO_TARGET, cmd_send_oneshot},
	{"sp", 2, 2, cmd_sp_oneshot},
	{"str", 1, 1, cmd_str_oneshot},
	{"tch-dl", 1, 1, cmd_tchdl_oneshot},
	{"tgtreset", 0, 0, cmd_tgtreset},
	{"unterm", 1, 1, cmd_unterm_oneshot},
	{0, 0, 0, 0}
};

oneshot_command(argc, argv)
	char **argv;
{
	struct cmdtab *tp;

	if (!strncmp(argv[0], "AT", 2) || !strncmp(argv[0], "at", 2)) {
		if (argc != 1) {
			fprintf(stderr,
			"error: AT command must be a single argument\n");
			exit(ERROR_USAGE);
		}
		return oneshot_at_command(argv[0]);
	}
	for (tp = cmdtab; tp->cmd; tp++)
		if (!strcmp(tp->cmd, argv[0]))
			break;
	if (!tp->func) {
		fprintf(stderr,
			"error: \"%s\" is not a valid one-shot command\n",
			argv[0]);
		exit(ERROR_USAGE);
	}
	if (argc - 1 > tp->maxargs) {
		fprintf(stderr, "%s: too many arguments\n", tp->cmd);
		exit(ERROR_USAGE);
	}
	if (argc - 1 < tp->minargs) {
		fprintf(stderr, "%s: too few arguments\n", tp->cmd);
		exit(ERROR_USAGE);
	}
	return tp->func(argc, argv);
}