command.c

/*	$NetBSD: command.c,v 1.3 1997/09/15 01:29:30 lukem Exp $	*/

/*
 * Copyright (c) 1994 Philip A. Nelson.
 * All rights reserved.
 *
 * 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. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Philip A. Nelson.
 * 4. The name of Philip A. Nelson may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY PHILIP NELSON ``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 PHILIP NELSON 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 <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: command.c,v 1.3 1997/09/15 01:29:30 lukem Exp $");
#endif /* not lint */

/*
 * command.c - The routines to implement the command processor.
 *
 *   The user must add to "cmdtable.h" all commands that are  available.
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>

#include "command.h"
#include "cmdtable.h"
#include "extern.h"


/* This allows the user to define the prompt in cmdtable.h */
#ifndef PROMPT
#define PROMPT "Command (? for help): "
#endif


/* Other procedure prototypes. */
const struct command *find_entry __P((char *));
void	help_cmds __P((void));
int	parse __P((char *, char **));
int	StrCmp __P((char *, char *));

/* A pointer to a function to be called after every command.
   A NULL pointer says no function is to be executed.
   The int parameter is the "done" flag.. TRUE => last command */

void (*after_cmd) __P((int)) = NULL;

/* This is the command processor loop. */
void
command_loop()
{
	char    cmdline[LINELEN];
	char   *args[MAXARGS];
	int     numargs;
	const struct command *cmd;
	int     done = FALSE;

	while (!done) {
		prompt(cmdline, LINELEN, PROMPT);
		numargs = parse(cmdline, args);
		if (numargs == BLANK_LINE)
			continue;
		cmd = find_entry(args[0]);
		if (cmd != NULL) {
			done = (*(cmd->fn)) (numargs, args, cmd->syntax);
			if (after_cmd != NULL)
				(*(after_cmd)) (done);
		} else
			printf("Unknown command\n");
	}
}

/* This is the command processor for a single command. */
int
one_command(cmdline)
	char   *cmdline;
{
	char   *args[MAXARGS];
	int     numargs;
	const struct command *cmd;
	int     done;

	numargs = parse(cmdline, args);
	if (numargs == BLANK_LINE)
		return 0;
	cmd = find_entry(args[0]);
	if (cmd != NULL) {
		done = (*(cmd->fn)) (numargs, args, cmd->syntax);
		if (after_cmd != NULL)
			(*(after_cmd)) (done);
		return done;
	} else
		return 0;
}

/* prompt procedure....  Write out the prompt and then read a response. */
void 
prompt(cmdline, linelen, promptstr)
	char   *cmdline;
	int     linelen;
	const char   *promptstr;
{
	int     incount = 0;
	int     inchar;

	/* Give the prompt. */
	printf("%s", promptstr);
	fflush(stdout);

	/* Read chars until newline or EOF, toss chars that won't fit in the
	 * array. */
	while (TRUE) {
		inchar = getchar();
		if (inchar == '\n' || inchar == EOF)
			break;
		if (++incount < linelen)
			*cmdline++ = inchar;
	}
	*cmdline = 0;
}

/*
 * parse the arguments on an input line.  It returns an array of
 * pointers to substrings in the original string.  It puts the string
 * terminator in the original line.
 */
int 
parse(cmdline, args)
	char   *cmdline;
	char  **args;
{
	int     index;
	int     argcnt = BLANK_LINE;

	/* Initialize the args. */
	for (index = 0; index < MAXARGS; index++)
		args[index] = NULL;

	/* Start looking for the commands */
	while (*cmdline != 0) {
		while (isspace(*cmdline))
			cmdline++;	/* skip blanks. */
		if (*cmdline != 0) {
			/* Start of new argument. */
			if (argcnt < MAXARGS)
				args[argcnt] = cmdline;
			while (!isspace(*cmdline) && *cmdline != 0)
				cmdline++;
			if (*cmdline != 0)
				*cmdline++ = 0;
			argcnt++;
		}
	}
	return (argcnt < MAXARGS ? argcnt : MAXARGS - 1);
}

/* Search cmd_tbl for 1) a command matching what the user typed or 2)
 * a unique command which is a superstring of what the user typed.
 */
const struct command *
find_entry(name)
	char   *name;
{
	const struct command *item, *save;
	int     subcount = 0;

	save = NULL;
	for (item = cmd_table; item < cmd_table + CMDLEN; item++)
		switch (StrCmp(name, item->name)) {
		case CMP_MATCH:
			return item;
		case CMP_SUBSTR:
			subcount++;
			save = item;
			break;
		case CMP_NOMATCH:
			break;
		}
	return (subcount == 1) ? save : NULL;
}

/*
 * Returns CMP_MATCH if strings are the same, CMP_SUBSTR if p1 is a
 * proper substring of p2, and CMP_NOMATCH if neither.
 */
int
StrCmp(p1, p2)
	char   *p1, *p2;
{
	while (*p1 == *p2 && *p1 != '\0') {
		++p1;
		++p2;
	}
	if (*p1 == '\0')
		return (*p2 == '\0') ? CMP_MATCH : CMP_SUBSTR;
	return CMP_NOMATCH;
}


/* Other routines that may be helpful in evaluating arguments....  */
int
Str2Int(str, num)
	char   *str;
	int    *num;
{
	if (!isdigit(*str) && *str != '-')
		return FALSE;
	*num = atoi(str);
	return TRUE;
}


#ifndef NO_HELP
/* "?" command handler.  Print help and list of commands. */

void
help_cmds()
{
	const struct command *q;

	printf("\nFor additional help, type HELP <command>.  Commands are:\n");
	for (q = cmd_table; q < cmd_table + CMDLEN; ++q)
		if ((q - cmd_table) % 5 == 4)
			printf("%s\n", q->name);
		else
			printf("%-15s", q->name) ;
	if ((q - cmd_table) % 5 != 0)
		printf("\n");
	printf("\n");
}

/* The default help routine.  This may be redefined by the user. */
int 
help(num, args, syntax)
	int     num;
	char  **args;
	char   *syntax;
{
	const struct command *item;
	int     index;
	int     show_cmds = FALSE;
	char    dummy[2];

	if (args[0][0] == '?')
		num = 1;	/* Force "no args" for ?. */

	/* Print help for each argument. */
	if (num > 1)
		for (index = 1; index < num; index++) {
			item = find_entry(args[index]);
			if (item != NULL) {
				printf("\n");
				if (item->syntax[0] != 0)
					printf("Syntax: %s\n", item->syntax);
				printf("%s\n\n", item->help);
				if (index < num - 1)
					prompt(dummy, 1, "cr to continue:");
			} else {
				printf("unknow command %s.\n", args[index]);
				show_cmds = TRUE;
			}
		}

	if (show_cmds || num == 1)
		help_cmds();

	return FALSE;
}
#endif