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bertos/mware/parser.c

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+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2003, 2006 Develer S.r.l. (http://www.develer.com/)
+ * All Rights Reserved.
+ * -->
+ *
+ * \brief Channel protocol parser and commands.
+ *
+ * This file contains the channel protocol parser and
+ * the definition of the protocol commands. Commands are defined
+ * in a "CmdTemplate" type array, containing:
+ * - the name of the command,
+ * - the arguments it expects to receive,
+ * - the output values,
+ * - the name of the function implementing the command.
+ *
+ * The arguments and results are passed to command function
+ * using an union: the element of the union to use for each
+ * argument is determined by format strings present in the
+ * CmdTemplate table.
+ *
+ * \author Bernie Innocenti <bernie@codewiz.org>
+ * \author Stefano Fedrigo <aleph@develer.com>
+ * \author Giovanni Bajo <rasky@develer.com>
+ *
+ *
+ */
+
+
+#include "parser.h"
+
+#include "cfg/cfg_parser.h"
+
+#include <io/kfile.h>
+#include <struct/hashtable.h>
+
+#include <stdlib.h> // atol(), NULL
+#include <string.h> // strchr(), strcmp()
+
+/// Hashtable hook to extract the key from a command
+static const void* get_key_from_command(const void* cmd, uint8_t* length);
+
+/// Hashtable that handles the commands that can be executed
+DECLARE_HASHTABLE_STATIC(commands, CONFIG_MAX_COMMANDS_NUMBER, get_key_from_command);
+
+
+/**
+ * \brief Tokenize one word at a time from a text.
+ *
+ * This function is similar to strtok, but does not use any implicit
+ * context, nor it does modify the input buffer in any form.
+ * The word is returned as a STL-like [begin,end) range.
+ *
+ * To extract the first word, make both begin and end point at the
+ * start of the text, and call the function. Then, subsequent
+ * calls will return the following words (assuming the begin/end
+ * variable are not modified between calls).
+ *
+ * \param begin Will contain the index of the first character of the word
+ * \param end Will contain the index of the character after the last
+ *     character of the word
+ *
+ * \return True if a word was extracted, false if we got to the end
+ * of the string without extracting any word.
+ */
+static bool get_word(const char **begin, const char **end)
+{
+	const char *cur = *end;
+
+	while ((*cur == ' ' || *cur == '\t') && *cur)
+		++cur;
+
+	*begin = cur;
+
+	while ((*cur != ' ' && *cur != '\t') && *cur)
+		++cur;
+
+	*end = cur;
+
+	return (*end != *begin);
+}
+
+
+/**
+ * \brief Command arguments parser.
+ *
+ * Using the format pointed by the argument fmt
+ * parses the input string filling the array argv
+ * with input parameters of the correct type.
+ *
+ * \param fmt   Parameters format string.
+ * \param input Input string.
+ * \param argv  Array filled with parameters.
+ *
+ * \return False in case of errors, otherwise true.
+ */
+static bool parseArgs(const char *fmt, const char *input, parms argv[])
+{
+	const char *begin = input, *end = input;
+
+	while (*fmt)
+	{
+		// Extract the argument
+		if (!get_word(&begin, &end))
+			return false;
+
+		switch (*fmt)
+		{
+			case 'd':
+				(*argv++).l = atol(begin);
+				break;
+
+			case 's':
+				(*argv++).s = begin;
+				break;
+
+			default:
+				ASSERT2(0, "Unknown format for argument");
+				return false;
+		}
+
+		++fmt;
+	}
+
+	/* check if there are remaining args */
+	if (get_word(&begin, &end))
+		return false;
+
+	return true;
+}
+
+/// Hook provided by the parser for matching of command names (TAB completion) for readline
+const char* parser_rl_match(UNUSED_ARG(void *,dummy), const char *word, int word_len)
+{
+	HashIterator cur;
+	HashIterator end = ht_iter_end(&commands);
+	const char *found = NULL;
+
+	for (cur = ht_iter_begin(&commands);
+	     !ht_iter_cmp(cur, end);
+	     cur = ht_iter_next(cur))
+	{
+		const struct CmdTemplate* cmdp = (const struct CmdTemplate*)ht_iter_get(cur);
+		if (strncmp(cmdp->name, word, word_len) == 0)
+		{
+			// If there was another matching word, it means that we have a multiple
+			//  match: then return NULL.
+			if (found)
+				return NULL;
+
+			found = cmdp->name;
+		}
+	}
+
+	return found;
+}
+
+#if CONFIG_ENABLE_COMPAT_BEHAVIOUR
+bool parser_get_cmd_id(const char* line, unsigned long* ID)
+{
+	const char *begin = line, *end = line;
+	char *end2;
+
+	// The first word is the ID
+	if (!get_word(&begin, &end))
+		return false;
+
+	*ID = strtoul(begin, &end2, 10);
+	if (end2 != end)
+		return false;
+
+	return true;
+}
+#endif
+
+/**
+ * Find the template for the command contained in the text line.
+ * The template can be used to tokenize the command and interpret
+ * it.
+ *
+ * This function can be used to find out which command is contained
+ * in a given text line without parsing all the parameters and
+ * executing it.
+ *
+ * \param input Text line to be processed (ASCIIZ)
+ *
+ * \return The command template associated with the command contained
+ * in the line, or NULL if the command is invalid.
+ */
+const struct CmdTemplate* parser_get_cmd_template(const char *input)
+{
+	const char *begin = input, *end = input;
+
+#if CONFIG_ENABLE_COMPAT_BEHAVIOUR
+	// Skip the ID, and get the command
+	if (!get_word(&begin, &end))
+		return NULL;
+#endif
+	if (!get_word(&begin, &end))
+		return NULL;
+
+	return (const struct CmdTemplate*)ht_find(&commands, begin, end-begin);
+}
+
+static const char *skip_to_params(const char *input, const struct CmdTemplate *cmdp)
+{
+	const char *begin = input, *end = input;
+
+#if CONFIG_ENABLE_COMPAT_BEHAVIOUR
+	// Skip the ID, and get the command
+	if (!get_word(&begin, &end))
+		return NULL;
+#endif
+	if (!get_word(&begin, &end))
+		return NULL;
+
+	ASSERT2(strlen(cmdp->name) == (size_t)(end-begin), "Invalid command template specified");
+	ASSERT2(!strncmp(begin, cmdp->name, end-begin), "Invalid command template specified");
+
+	return end;
+}
+
+/**
+ * Extract the arguments for the command contained in the text line.
+ *
+ * The first argument will always be the command name, so the actual arguments
+ * will start at index 1.
+ *
+ * \param input Text line to be processed (ASCIIZ)
+ * \param cmdp Command template for this line
+ * \param args Will contain the extracted parameters
+ *
+ * \return True if everything OK, false in case of parsing error.
+ */
+bool parser_get_cmd_arguments(const char* input, const struct CmdTemplate* cmdp, parms args[CONFIG_PARSER_MAX_ARGS])
+{
+	input = skip_to_params(input, cmdp);
+	if (!input)
+		return false;
+
+	args[0].s = cmdp->name;
+	if (!parseArgs(cmdp->arg_fmt, input, args + 1))
+		return false;
+
+	return true;
+}
+
+static const void* get_key_from_command(const void* cmd, uint8_t* length)
+{
+	const struct CmdTemplate* c = cmd;
+	*length = strlen(c->name);
+	return c->name;
+}
+
+/**
+ * \brief Command input handler.
+ *
+ * Process the input, calling the requested command (if found).
+ *
+ * \param input Text line to be processed (ASCIIZ)
+ *
+ * \return true if everything is OK, false in case of errors
+ */
+bool parser_process_line(const char* input)
+{
+	const struct CmdTemplate *cmdp;
+	parms args[CONFIG_PARSER_MAX_ARGS];
+
+	cmdp = parser_get_cmd_template(input);
+	if (!cmdp)
+		return false;
+
+	if (!parser_get_cmd_arguments(input, cmdp, args))
+		return false;
+
+	if (!parser_execute_cmd(cmdp, args))
+		return false;
+
+	return true;
+}
+
+/**
+ * Register a new command into the parser
+ *
+ * \param cmd Command template describing the command
+ * \return true if registration was successful, false otherwise
+ */
+bool parser_register_cmd(const struct CmdTemplate* cmd)
+{
+	return ht_insert(&commands, cmd);
+}
+
+void parser_init(void)
+{
+	// Initialize the hashtable used to store the command description
+	ht_init(&commands);
+}