319 lines
9.5 KiB
C
319 lines
9.5 KiB
C
/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#include "config.h"
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#include "guacamole/error.h"
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#include "guacamole/parser.h"
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#include "guacamole/socket.h"
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#include "guacamole/unicode.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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static void guac_parser_reset(guac_parser* parser) {
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parser->opcode = NULL;
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parser->argc = 0;
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parser->state = GUAC_PARSE_LENGTH;
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parser->__elementc = 0;
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parser->__element_length = 0;
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}
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guac_parser* guac_parser_alloc() {
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/* Allocate space for parser */
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guac_parser* parser = malloc(sizeof(guac_parser));
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if (parser == NULL) {
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guac_error = GUAC_STATUS_NO_MEMORY;
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guac_error_message = "Insufficient memory to allocate parser";
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return NULL;
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}
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/* Init parse start/end markers */
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parser->__instructionbuf_unparsed_start = parser->__instructionbuf;
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parser->__instructionbuf_unparsed_end = parser->__instructionbuf;
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guac_parser_reset(parser);
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return parser;
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}
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int guac_parser_append(guac_parser* parser, void* buffer, int length) {
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char* char_buffer = (char*) buffer;
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int bytes_parsed = 0;
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/* Do not exceed maximum number of elements */
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if (parser->__elementc == GUAC_INSTRUCTION_MAX_ELEMENTS
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&& parser->state != GUAC_PARSE_COMPLETE) {
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parser->state = GUAC_PARSE_ERROR;
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return 0;
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}
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/* Parse element length */
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if (parser->state == GUAC_PARSE_LENGTH) {
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int parsed_length = parser->__element_length;
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while (bytes_parsed < length) {
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/* Pull next character */
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char c = *(char_buffer++);
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bytes_parsed++;
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/* If digit, add to length */
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if (c >= '0' && c <= '9')
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parsed_length = parsed_length*10 + c - '0';
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/* If period, switch to parsing content */
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else if (c == '.') {
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parser->__elementv[parser->__elementc++] = char_buffer;
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parser->state = GUAC_PARSE_CONTENT;
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break;
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}
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/* If not digit, parse error */
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else {
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parser->state = GUAC_PARSE_ERROR;
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return 0;
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}
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}
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/* If too long, parse error */
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if (parsed_length > GUAC_INSTRUCTION_MAX_LENGTH) {
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parser->state = GUAC_PARSE_ERROR;
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return 0;
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}
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/* Save length */
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parser->__element_length = parsed_length;
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} /* end parse length */
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/* Parse element content */
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if (parser->state == GUAC_PARSE_CONTENT) {
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while (bytes_parsed < length && parser->__element_length >= 0) {
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/* Get length of current character */
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char c = *char_buffer;
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int char_length = guac_utf8_charsize((unsigned char) c);
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/* If full character not present in buffer, stop now */
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if (char_length + bytes_parsed > length)
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break;
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/* Record character as parsed */
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bytes_parsed += char_length;
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/* If end of element, handle terminator */
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if (parser->__element_length == 0) {
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*char_buffer = '\0';
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/* If semicolon, store end-of-instruction */
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if (c == ';') {
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parser->state = GUAC_PARSE_COMPLETE;
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parser->opcode = parser->__elementv[0];
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parser->argv = &(parser->__elementv[1]);
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parser->argc = parser->__elementc - 1;
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break;
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}
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/* If comma, move on to next element */
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else if (c == ',') {
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parser->state = GUAC_PARSE_LENGTH;
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break;
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}
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/* Otherwise, parse error */
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else {
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parser->state = GUAC_PARSE_ERROR;
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return 0;
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}
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} /* end if end of element */
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/* Advance to next character */
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parser->__element_length--;
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char_buffer += char_length;
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}
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} /* end parse content */
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return bytes_parsed;
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}
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int guac_parser_read(guac_parser* parser, guac_socket* socket, int usec_timeout) {
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char* unparsed_end = parser->__instructionbuf_unparsed_end;
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char* unparsed_start = parser->__instructionbuf_unparsed_start;
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char* instr_start = parser->__instructionbuf_unparsed_start;
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char* buffer_end = parser->__instructionbuf + sizeof(parser->__instructionbuf);
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/* Begin next instruction if previous was ended */
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if (parser->state == GUAC_PARSE_COMPLETE)
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guac_parser_reset(parser);
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while (parser->state != GUAC_PARSE_COMPLETE
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&& parser->state != GUAC_PARSE_ERROR) {
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/* Add any available data to buffer */
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int parsed = guac_parser_append(parser, unparsed_start, unparsed_end - unparsed_start);
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/* Read more data if not enough data to parse */
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if (parsed == 0 && parser->state != GUAC_PARSE_ERROR) {
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int retval;
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/* If no space left to read, fail */
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if (unparsed_end == buffer_end) {
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/* Shift backward if possible */
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if (instr_start != parser->__instructionbuf) {
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int i;
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/* Shift buffer */
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int offset = instr_start - parser->__instructionbuf;
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memmove(parser->__instructionbuf, instr_start,
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unparsed_end - instr_start);
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/* Update tracking pointers */
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unparsed_end -= offset;
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unparsed_start -= offset;
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instr_start = parser->__instructionbuf;
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/* Update parsed elements, if any */
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for (i=0; i < parser->__elementc; i++)
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parser->__elementv[i] -= offset;
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}
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/* Otherwise, no memory to read */
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else {
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guac_error = GUAC_STATUS_NO_MEMORY;
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guac_error_message = "Instruction too long";
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return -1;
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}
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}
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/* No instruction yet? Get more data ... */
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retval = guac_socket_select(socket, usec_timeout);
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if (retval <= 0)
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return -1;
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/* Attempt to fill buffer */
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retval = guac_socket_read(socket, unparsed_end,
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buffer_end - unparsed_end);
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/* Set guac_error if read unsuccessful */
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if (retval < 0) {
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guac_error = GUAC_STATUS_SEE_ERRNO;
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guac_error_message = "Error filling instruction buffer";
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return -1;
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}
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/* EOF */
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if (retval == 0) {
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guac_error = GUAC_STATUS_CLOSED;
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guac_error_message = "End of stream reached while "
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"reading instruction";
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return -1;
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}
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/* Update internal buffer */
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unparsed_end += retval;
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}
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/* If data was parsed, advance buffer */
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else
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unparsed_start += parsed;
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} /* end while parsing data */
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/* Fail on error */
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if (parser->state == GUAC_PARSE_ERROR) {
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guac_error = GUAC_STATUS_PROTOCOL_ERROR;
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guac_error_message = "Instruction parse error";
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return -1;
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}
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parser->__instructionbuf_unparsed_start = unparsed_start;
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parser->__instructionbuf_unparsed_end = unparsed_end;
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return 0;
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}
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int guac_parser_expect(guac_parser* parser, guac_socket* socket, int usec_timeout, const char* opcode) {
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/* Read next instruction */
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if (guac_parser_read(parser, socket, usec_timeout) != 0)
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return -1;
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/* Validate instruction */
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if (strcmp(parser->opcode, opcode) != 0) {
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guac_error = GUAC_STATUS_PROTOCOL_ERROR;
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guac_error_message = "Instruction read did not have expected opcode";
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return -1;
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}
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/* Return non-zero only if valid instruction read */
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return parser->state != GUAC_PARSE_COMPLETE;
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}
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int guac_parser_length(guac_parser* parser) {
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char* unparsed_end = parser->__instructionbuf_unparsed_end;
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char* unparsed_start = parser->__instructionbuf_unparsed_start;
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return unparsed_end - unparsed_start;
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}
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int guac_parser_shift(guac_parser* parser, void* buffer, int length) {
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char* copy_end = parser->__instructionbuf_unparsed_end;
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char* copy_start = parser->__instructionbuf_unparsed_start;
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/* Contain copy region within length */
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if (copy_end - copy_start > length)
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copy_end = copy_start + length;
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/* Copy buffer */
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length = copy_end - copy_start;
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memcpy(buffer, copy_start, length);
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parser->__instructionbuf_unparsed_start = copy_end;
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return length;
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}
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void guac_parser_free(guac_parser* parser) {
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free(parser);
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}
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