main.c

		c = getc();

		/*
		 * Special character handling
		 */
		switch (c) {
		case '\r':				/* Enter		*/
		case '\n':
			*p = '\0';
			puts ("\r\n");
			return (p - p_buf);

		case '\0':				/* nul			*/
			continue;

		case 0x03:				/* ^C - break		*/
			p_buf[0] = '\0';	/* discard input */
			return (-1);

		case 0x15:				/* ^U - erase line	*/
			while (col > plen) {
				puts (erase_seq);
				--col;
			}
			p = p_buf;
			n = 0;
			continue;

		case 0x17:				/* ^W - erase word	*/
			p=delete_char(p_buf, p, &col, &n, plen);
			while ((n > 0) && (*p != ' ')) {
				p=delete_char(p_buf, p, &col, &n, plen);
			}
			continue;

		case 0x08:				/* ^H  - backspace	*/
		case 0x7F:				/* DEL - backspace	*/
			p=delete_char(p_buf, p, &col, &n, plen);
			continue;

		default:
			/*
			 * Must be a normal character then
			 */
			if (n < CONFIG_SYS_CBSIZE-2) {
				if (c == '\t') {	/* expand TABs		*/
#ifdef CONFIG_AUTO_COMPLETE
					/* if auto completion triggered just continue */
					*p = '\0';
					if (cmd_auto_complete(prompt, console_buffer, &n, &col)) {
						p = p_buf + n;	/* reset */
						continue;
					}
#endif
					puts (tab_seq+(col&07));
					col += 8 - (col&07);
				} else {
					++col;		/* echo input		*/
					putc (c);
				}
				*p++ = c;
				++n;
			} else {			/* Buffer full		*/
				putc ('\a');
			}
		}
	}
#ifdef CONFIG_CMDLINE_EDITING
	}
#endif
}

/****************************************************************************/

static char * delete_char (char *buffer, char *p, int *colp, int *np, int plen)
{
	char *s;

	if (*np == 0) {
		return (p);
	}

	if (*(--p) == '\t') {			/* will retype the whole line	*/
		while (*colp > plen) {
			puts (erase_seq);
			(*colp)--;
		}
		for (s=buffer; s<p; ++s) {
			if (*s == '\t') {
				puts (tab_seq+((*colp) & 07));
				*colp += 8 - ((*colp) & 07);
			} else {
				++(*colp);
				putc (*s);
			}
		}
	} else {
		puts (erase_seq);
		(*colp)--;
	}
	(*np)--;
	return (p);
}

/****************************************************************************/

int parse_line (char *line, char *argv[])
{
	int nargs = 0;

#ifdef DEBUG_PARSER
	printf ("parse_line: \"%s\"\n", line);
#endif
	while (nargs < CONFIG_SYS_MAXARGS) {

		/* skip any white space */
		while (isblank(*line))
			++line;

		if (*line == '\0') {	/* end of line, no more args	*/
			argv[nargs] = NULL;
#ifdef DEBUG_PARSER
		printf ("parse_line: nargs=%d\n", nargs);
#endif
			return (nargs);
		}

		argv[nargs++] = line;	/* begin of argument string	*/

		/* find end of string */
		while (*line && !isblank(*line))
			++line;

		if (*line == '\0') {	/* end of line, no more args	*/
			argv[nargs] = NULL;
#ifdef DEBUG_PARSER
		printf ("parse_line: nargs=%d\n", nargs);
#endif
			return (nargs);
		}

		*line++ = '\0';		/* terminate current arg	 */
	}

	printf ("** Too many args (max. %d) **\n", CONFIG_SYS_MAXARGS);

#ifdef DEBUG_PARSER
	printf ("parse_line: nargs=%d\n", nargs);
#endif
	return (nargs);
}

/****************************************************************************/

static void process_macros (const char *input, char *output)
{
	char c, prev;
	const char *varname_start = NULL;
	int inputcnt = strlen (input);
	int outputcnt = CONFIG_SYS_CBSIZE;
	int state = 0;		/* 0 = waiting for '$'  */

	/* 1 = waiting for '(' or '{' */
	/* 2 = waiting for ')' or '}' */
	/* 3 = waiting for '''  */
#ifdef DEBUG_PARSER
	char *output_start = output;

	printf ("[PROCESS_MACROS] INPUT len %d: \"%s\"\n", strlen (input),
		input);
#endif

	prev = '\0';		/* previous character   */

	while (inputcnt && outputcnt) {
		c = *input++;
		inputcnt--;

		if (state != 3) {
			/* remove one level of escape characters */
			if ((c == '\\') && (prev != '\\')) {
				if (inputcnt-- == 0)
					break;
				prev = c;
				c = *input++;
			}
		}

		switch (state) {
		case 0:	/* Waiting for (unescaped) $    */
			if ((c == '\'') && (prev != '\\')) {
				state = 3;
				break;
			}
			if ((c == '$') && (prev != '\\')) {
				state++;
			} else {
				*(output++) = c;
				outputcnt--;
			}
			break;
		case 1:	/* Waiting for (        */
			if (c == '(' || c == '{') {
				state++;
				varname_start = input;
			} else {
				state = 0;
				*(output++) = '$';
				outputcnt--;

				if (outputcnt) {
					*(output++) = c;
					outputcnt--;
				}
			}
			break;
		case 2:	/* Waiting for )        */
			if (c == ')' || c == '}') {
				int i;
				char envname[CONFIG_SYS_CBSIZE], *envval;
				int envcnt = input - varname_start - 1;	/* Varname # of chars */

				/* Get the varname */
				for (i = 0; i < envcnt; i++) {
					envname[i] = varname_start[i];
				}
				envname[i] = 0;

				/* Get its value */
				envval = getenv (envname);

				/* Copy into the line if it exists */
				if (envval != NULL)
					while ((*envval) && outputcnt) {
						*(output++) = *(envval++);
						outputcnt--;
					}
				/* Look for another '$' */
				state = 0;
			}
			break;
		case 3:	/* Waiting for '        */
			if ((c == '\'') && (prev != '\\')) {
				state = 0;
			} else {
				*(output++) = c;
				outputcnt--;
			}
			break;
		}
		prev = c;
	}

	if (outputcnt)
		*output = 0;
	else
		*(output - 1) = 0;

#ifdef DEBUG_PARSER
	printf ("[PROCESS_MACROS] OUTPUT len %d: \"%s\"\n",
		strlen (output_start), output_start);
#endif
}

/****************************************************************************
 * returns:
 *	1  - command executed, repeatable
 *	0  - command executed but not repeatable, interrupted commands are
 *	     always considered not repeatable
 *	-1 - not executed (unrecognized, bootd recursion or too many args)
 *           (If cmd is NULL or "" or longer than CONFIG_SYS_CBSIZE-1 it is
 *           considered unrecognized)
 *
 * WARNING:
 *
 * We must create a temporary copy of the command since the command we get
 * may be the result from getenv(), which returns a pointer directly to
 * the environment data, which may change magicly when the command we run
 * creates or modifies environment variables (like "bootp" does).
 */

int builtin_run_command(const char *cmd, int flag)
{
	cmd_tbl_t *cmdtp;
	char cmdbuf[CONFIG_SYS_CBSIZE];	/* working copy of cmd		*/
	char *token;			/* start of token in cmdbuf	*/
	char *sep;			/* end of token (separator) in cmdbuf */
	char finaltoken[CONFIG_SYS_CBSIZE];
	char *str = cmdbuf;
	char *argv[CONFIG_SYS_MAXARGS + 1];	/* NULL terminated	*/
	int argc, inquotes;
	int repeatable = 1;
	int rc = 0;

#ifdef DEBUG_PARSER
	printf ("[RUN_COMMAND] cmd[%p]=\"", cmd);
	puts (cmd ? cmd : "NULL");	/* use puts - string may be loooong */
	puts ("\"\n");
#endif

	clear_ctrlc();		/* forget any previous Control C */

	if (!cmd || !*cmd) {
		return -1;	/* empty command */
	}

	if (strlen(cmd) >= CONFIG_SYS_CBSIZE) {
		puts ("## Command too long!\n");
		return -1;
	}

	strcpy (cmdbuf, cmd);

	/* Process separators and check for invalid
	 * repeatable commands
	 */

#ifdef DEBUG_PARSER
	printf ("[PROCESS_SEPARATORS] %s\n", cmd);
#endif
	while (*str) {

		/*
		 * Find separator, or string end
		 * Allow simple escape of ';' by writing "\;"
		 */
		for (inquotes = 0, sep = str; *sep; sep++) {
			if ((*sep=='\'') &&
			    (*(sep-1) != '\\'))
				inquotes=!inquotes;

			if (!inquotes &&
			    (*sep == ';') &&	/* separator		*/
			    ( sep != str) &&	/* past string start	*/
			    (*(sep-1) != '\\'))	/* and NOT escaped	*/
				break;
		}

		/*
		 * Limit the token to data between separators
		 */
		token = str;
		if (*sep) {
			str = sep + 1;	/* start of command for next pass */
			*sep = '\0';
		}
		else
			str = sep;	/* no more commands for next pass */
#ifdef DEBUG_PARSER
		printf ("token: \"%s\"\n", token);
#endif

		/* find macros in this token and replace them */
		process_macros (token, finaltoken);

		/* Extract arguments */
		if ((argc = parse_line (finaltoken, argv)) == 0) {
			rc = -1;	/* no command at all */
			continue;
		}

		/* Look up command in command table */
		if ((cmdtp = find_cmd(argv[0])) == NULL) {
			printf ("Unknown command '%s' - try 'help'\n", argv[0]);
			rc = -1;	/* give up after bad command */
			continue;
		}

		/* found - check max args */
		if (argc > cmdtp->maxargs) {
			cmd_usage(cmdtp);
			rc = -1;
			continue;
		}

#if defined(CONFIG_CMD_BOOTD)
		/* avoid "bootd" recursion */
		if (cmdtp->cmd == do_bootd) {
#ifdef DEBUG_PARSER
			printf ("[%s]\n", finaltoken);
#endif
			if (flag & CMD_FLAG_BOOTD) {
				puts ("'bootd' recursion detected\n");
				rc = -1;
				continue;
			} else {
				flag |= CMD_FLAG_BOOTD;
			}
		}
#endif

		/* OK - call function to do the command */
		if ((cmdtp->cmd) (cmdtp, flag, argc, argv) != 0) {
			rc = -1;
		}

		repeatable &= cmdtp->repeatable;

		/* Did the user stop this? */
		if (had_ctrlc ())
			return -1;	/* if stopped then not repeatable */
	}

	return rc ? rc : repeatable;
}

/****************************************************************************/

#if defined(CONFIG_CMD_RUN)
int do_run (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
	int i;

	if (argc < 2)
		return cmd_usage(cmdtp);

	for (i=1; i<argc; ++i) {
		char *arg;

		if ((arg = getenv (argv[i])) == NULL) {
			printf ("## Error: \"%s\" not defined\n", argv[i]);
			return 1;
		}

		if (run_command2(arg, flag) != 0)
			return 1;
	}
	return 0;
}
#endif