error_api.php

<?php
# MantisBT - A PHP based bugtracking system

# MantisBT 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.
#
# MantisBT 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 MantisBT.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Error API
 *
 * @package CoreAPI
 * @subpackage ErrorAPI
 * @copyright Copyright 2000 - 2002  Kenzaburo Ito - kenito@300baud.org
 * @copyright Copyright 2002  MantisBT Team - mantisbt-dev@lists.sourceforge.net
 * @link http://www.mantisbt.org
 *
 * @uses compress_api.php
 * @uses config_api.php
 * @uses constant_api.php
 * @uses database_api.php
 * @uses html_api.php
 * @uses lang_api.php
 */

require_api( 'compress_api.php' );
require_api( 'config_api.php' );
require_api( 'constant_inc.php' );
require_api( 'database_api.php' );
require_api( 'html_api.php' );
require_api( 'lang_api.php' );

$g_error_parameters = array();
$g_errors_delayed = array();
$g_error_handled = false;
$g_error_proceed_url = null;
$g_error_send_page_header = true;

# Make sure we always capture User-defined errors regardless of ini settings
# These can be disabled in config_inc.php, see $g_display_errors
error_reporting( error_reporting() | E_USER_ERROR | E_USER_WARNING | E_USER_NOTICE | E_USER_DEPRECATED );

global $g_bypass_error_handler;
if( !$g_bypass_error_handler ) {
	set_error_handler( 'error_handler' );
	set_exception_handler( 'error_exception_handler' );
}

$g_exception = null;

/**
 * Unhandled exception handler
 *
 * @param Exception|Error $p_exception The exception to handle
 * @return void
 */
function error_exception_handler( $p_exception ) {
	global $g_exception;

	# As per PHP documentation, null may be received to reset handler to default state.
	if( $p_exception === null ) {
		$g_exception = null;
		return;
	}

	$g_exception = $p_exception;

	if( is_a( $p_exception, 'MantisException' ) ) {
		$t_params = $p_exception->getParams();
		if( !empty( $t_params ) ) {
			call_user_func_array( 'error_parameters', $t_params );
		}

		trigger_error( $p_exception->getCode(), ERROR );

		# It is not expected to get here, but just in case!
		return;
	}

	# trigger a generic error
	# TODO: we may want to log such errors
	trigger_error( ERROR_PHP, ERROR );
}

/**
 * Get error stack based on last exception
 * @return array The stack trace as an array
 */
function error_stack_trace() {
	global $g_exception;

	if ( $g_exception === null ) {
		$t_stack = debug_backtrace();

		# remove this function and its caller from the stack trace.
		array_shift( $t_stack );
		array_shift( $t_stack );
	} else {
		$t_stack = $g_exception->getTrace();
	}

	return $t_stack;
}

/**
 * Default error handler
 *
 * This handler will not receive E_ERROR, E_PARSE, E_CORE_*, or E_COMPILE_*
 *  errors.
 *
 * E_USER_* are triggered by us and will contain an error constant in $p_error
 * The others, being system errors, will come with a string in $p_error
 *
 * @access private
 * @param integer $p_type    Contains the level of the error raised, as an integer.
 * @param string  $p_error   Contains the error message, as a string.
 * @param string  $p_file    Contains the filename that the error was raised in, as a string.
 * @param integer $p_line    Contains the line number the error was raised at, as an integer.
 * @param array   $p_context To the active symbol table at the point the error occurred (optional).
 * @return void
 * @uses lang_api.php
 * @uses config_api.php
 * @uses compress_api.php
 * @uses database_api.php (optional)
 * @uses html_api.php (optional)
 */
function error_handler( $p_type, $p_error, $p_file, $p_line, array $p_context ) {
	global $g_error_parameters, $g_error_handled, $g_error_proceed_url;
	global $g_error_send_page_header;

	# check if errors were disabled with @ somewhere in this call chain
	if( 0 == error_reporting() ) {
		return;
	}

	$t_lang_pushed = false;

	$t_db_connected = false;
	if( function_exists( 'db_is_connected' ) ) {
		if( db_is_connected() ) {
			$t_db_connected = true;
		}
	}
	$t_html_api = false;
	if( function_exists( 'html_end' ) ) {
		$t_html_api = true;
	}

	# flush any language overrides to return to user's natural default
	if( $t_db_connected ) {
		lang_push( lang_get_default() );
		$t_lang_pushed = true;
	}

	$t_method_array = config_get_global( 'display_errors' );
	if( isset( $t_method_array[$p_type] ) ) {
		$t_method = $t_method_array[$p_type];
	} else {
		if( isset( $t_method_array[E_ALL] ) ) {
			$t_method = $t_method_array[E_ALL];
		} else {
			$t_method = 'none';
		}
	}

	# Force errors to use HALT method.
	if( $p_type == E_USER_ERROR || $p_type == E_ERROR || $p_type == E_RECOVERABLE_ERROR ) {
		$t_method = DISPLAY_ERROR_HALT;
	}

	# build an appropriate error string
	$t_error_location = 'in \'' . $p_file .'\' line ' . $p_line;
	$t_error_description = '\'' . $p_error . '\' ' . $t_error_location;
	switch( $p_type ) {
		case E_WARNING:
			$t_error_type = 'SYSTEM WARNING';
			break;
		case E_NOTICE:
			$t_error_type = 'SYSTEM NOTICE';
			break;
		case E_STRICT:
			$t_error_type = 'STRICT NOTICE';
			break;
		case E_RECOVERABLE_ERROR:
			# This should generally be considered fatal (like E_ERROR)
			$t_error_type = 'SYSTEM ERROR';
			break;
		case E_DEPRECATED:
			$t_error_type = 'DEPRECATED';
			break;
		case E_USER_ERROR:
			if( $p_error == ERROR_PHP ) {
				global $g_exception;
				$t_error_type = 'APPLICATION ERROR';
				$t_error_description = $g_exception->getMessage();
			} else {
				$t_error_type = 'APPLICATION ERROR #' . $p_error;
				$t_error_description = error_string( $p_error );
			}
			break;
		case E_USER_WARNING:
			$t_error_type = 'APPLICATION WARNING #' . $p_error;
			$t_error_description = error_string( $p_error ) . ' (' . $t_error_location . ')';
			break;
		case E_USER_NOTICE:
			# used for debugging
			$t_error_type = 'DEBUG';
			break;
		case E_USER_DEPRECATED:
			# Get the parent of the call that triggered the error to facilitate
			# debugging with a more useful filename and line number
			$t_stack = error_stack_trace();
			if( isset( $t_stack[2] ) ) {
				$t_caller = $t_stack[2];
			} else {
				# If called from main page body, there is no stack block for the funcion, use the page block instead
				$t_caller = $t_stack[1];
			}

			$t_error_type = 'WARNING';
			$t_error_description =  error_string( $p_error )
				. ' (in ' . $t_caller['file']
				. ' line ' . $t_caller['line'] . ')';

			if( $t_method == DISPLAY_ERROR_INLINE && php_sapi_name() != 'cli') {
				# Enqueue messages for later display with error_print_delayed()
				global $g_errors_delayed;
				$g_errors_delayed[] = $t_error_description;
				$g_error_handled = true;
				return;
			}
			break;
		default:
			# shouldn't happen, just display the error just in case
			$t_error_type = 'UNHANDLED ERROR TYPE (' .
				'<a href="http://php.net/errorfunc.constants">' . $p_type. '</a>)';
			$t_error_description = $p_error . ' (' . $t_error_location . ')';
	}

	$t_error_description = nl2br( $t_error_description );

	if( php_sapi_name() == 'cli' ) {
		if( DISPLAY_ERROR_NONE != $t_method ) {
			echo $t_error_type . ': ' . $t_error_description . "\n";

			if( ON == config_get_global( 'show_detailed_errors' ) ) {
				echo "\n";
				error_print_stack_trace();
			}
		}
		if( DISPLAY_ERROR_HALT == $t_method ) {
			exit(1);
		}
	} else {
		switch( $t_method ) {
			case DISPLAY_ERROR_HALT:
				# disable any further event callbacks
				if( function_exists( 'event_clear_callbacks' ) ) {
					event_clear_callbacks();
				}

				$t_oblen = ob_get_length();
				if( $t_oblen > 0 ) {
					$t_old_contents = ob_get_contents();
					if( !error_handled() ) {
						# Retrieve the previously output header
						if( false !== preg_match_all( '|^(.*)(</head>.*$)|is', $t_old_contents, $t_result ) &&
							isset( $t_result[1] ) && isset( $t_result[1][0] ) ) {
							$t_old_headers = $t_result[1][0];
							unset( $t_old_contents );
						}
					}
				}

				# We need to ensure compression is off - otherwise the compression headers are output.
				compress_disable();

				# then clean the buffer, leaving output buffering on.
				if( $t_oblen > 0 ) {
					ob_clean();
				}

				# If HTML error output was disabled, set an error header and stop
				if( defined( 'DISABLE_INLINE_ERROR_REPORTING' ) ) {
					# @TODO Have a mapping for mantis error codes to appropriate HTTP error codes
					header( ' ', true, 400 );
					exit(1);
				}

				# don't send the page header information if it has already been sent
				if( $g_error_send_page_header ) {
					if( $t_html_api ) {
						layout_page_header();
						if( $p_error != ERROR_DB_QUERY_FAILED && $t_db_connected == true ) {
							if( auth_is_user_authenticated() ) {
								layout_page_begin();
							} else {
								layout_navbar();
								layout_main_container_begin();
							}
						}
					} else {
                        layout_page_header( $t_error_type );
                    }
				} else {
					# Output the previously sent headers, if defined
					if( isset( $t_old_headers ) ) {
						echo $t_old_headers, "\n";
                        layout_page_header_end();
                        layout_page_begin();
					}
				}

				echo '<div class="col-md-12 col-xs-12">';
				echo '<div class="space-20"></div>';
				echo '<div class="alert alert-danger">';

				echo '<p class="bold">' . $t_error_type . '</p>';
				echo '<p>', $t_error_description, '</p>';

				echo '<div class="error-info">';
				if( null === $g_error_proceed_url ) {
					echo lang_get( 'error_no_proceed' );
				} else {
					echo '<a href="', $g_error_proceed_url, '">', lang_get( 'proceed' ), '</a>';
				}
				echo '</div>';

				if( ON == config_get_global( 'show_detailed_errors' ) ) {
					echo '<p>';
					error_print_details( $p_file, $p_line, $p_context );
					echo '</p>';
					echo '<p>';
					error_print_stack_trace();
					echo '</p>';
				}
				echo '</div></div>';

				if( isset( $t_old_contents ) ) {
					echo '<div class="col-md-12 col-xs-12">';
					echo '<div class="space-20"></div>';
					echo '<div class="alert alert-warning">';
					echo '<div class="warning">Previous non-fatal errors occurred.  Page contents follow.</div>';
					echo '<p>';
					echo $t_old_contents;
					echo '</p></div></div>';
				}

				if( $t_html_api ) {
					if( $p_error != ERROR_DB_QUERY_FAILED && $t_db_connected == true ) {
						if( auth_is_user_authenticated() ) {
							layout_page_end();
						} else {
							layout_main_container_end();
							layout_footer();
						}
					} else {
						layout_body_javascript();
						html_body_end();
						html_end();
					}
				} else {
					echo '</body></html>', "\n";
				}
				exit(1);

			case DISPLAY_ERROR_INLINE:
				if( !defined( 'DISABLE_INLINE_ERROR_REPORTING' ) ) {
					echo '<div class="alert alert-warning">', $t_error_type, ': ', $t_error_description, '</div>';
				}
				$g_error_handled = true;
				break;

			default:
				# do nothing - note we treat this as we've not handled an error, so any redirects go through.
		}
	}

	if( $t_lang_pushed ) {
		lang_pop();
	}

	$g_error_parameters = array();
	$g_error_proceed_url = null;
}

/**
 * Prints messages from the delayed errors queue
 * The error handler enqueues deprecation warnings that would be printed inline,
 * to avoid display issues when they are triggered within html tags.
 * @return void
 */
function error_print_delayed() {
	global $g_errors_delayed;

	if( !empty( $g_errors_delayed ) ) {
		echo '<div id="delayed-errors">';
		foreach( $g_errors_delayed as $t_error ) {
			echo "\n" . '<div class="error-inline">', $t_error, '</div>';
		}
		echo "\n" . '</div>';

		$g_errors_delayed = array();
	}
}

/**
 * Print out the error details including context
 * @param string  $p_file    File error occurred in.
 * @param integer $p_line    Line number error occurred on.
 * @param array   $p_context Error context.
 * @return void
 */
function error_print_details( $p_file, $p_line, array $p_context ) {
	?>
		<table class="width-100">
			<tr>
				<td>Full path: <?php echo htmlentities( $p_file, ENT_COMPAT, 'UTF-8' );?></td>
			</tr>
			<tr>
				<td>Line: <?php echo $p_line?></td>
			</tr>
			<tr>
				<td>
					<?php error_print_context( $p_context )?>
				</td>
			</tr>
		</table>
<?php
}

/**
 * Print out the variable context given
 * @param array $p_context Error context.
 * @return void
 */
function error_print_context( array $p_context ) {
	if( !is_array( $p_context ) ) {
		return;
	}

	echo '<table class="width100" style="table-layout:fixed;"><tr><th>Variable</th><th>Value</th><th>Type</th></tr>';

	# print normal variables
	foreach( $p_context as $t_var => $t_val ) {
		if( !is_array( $t_val ) && !is_object( $t_val ) ) {
			$t_type = gettype( $t_val );
			$t_val = htmlentities( (string)$t_val, ENT_COMPAT, 'UTF-8' );

			# Mask Passwords
			if( strpos( $t_var, 'password' ) !== false ) {
				$t_val = '**********';
			}

			echo '<tr><td style="width=20%; word-wrap:break-word; overflow:auto;">', $t_var,
				'</td><td style="width=70%; word-wrap:break-word; overflow:auto;">', $t_val,
				'</td><td style="width=10%;">', $t_type, '</td></tr>', "\n";
		}
	}

	# print arrays
	foreach( $p_context as $t_var => $t_val ) {
		if( is_array( $t_val ) && ( $t_var != 'GLOBALS' ) ) {
			echo '<tr><td colspan="3" style="word-wrap:break-word"><br /><strong>', $t_var, '</strong></td></tr>';
			echo '<tr><td colspan="3">';
			error_print_context( $t_val );
			echo '</td></tr>';
		}
	}

	echo '</table>';
}

/**
 * Print out a stack trace
 */
function error_print_stack_trace() {
	$t_stack = error_stack_trace();

	if( php_sapi_name() == 'cli' ) {
		foreach( $t_stack as $t_frame ) {
			echo ( isset( $t_frame['file'] ) ? $t_frame['file'] : '-' ), ': ' ,
				( isset( $t_frame['line'] ) ? $t_frame['line'] : '-' ), ': ',
				( isset( $t_frame['class'] ) ? $t_frame['class'] : '-' ), ' - ',
				( isset( $t_frame['type'] ) ? $t_frame['type'] : '-' ), ' - ',
				( isset( $t_frame['function'] ) ? $t_frame['function'] : '-' );
	
			$t_args = array();
			if( isset( $t_frame['args'] ) && !empty( $t_frame['args'] ) ) {
				foreach( $t_frame['args'] as $t_value ) {
					$t_args[] = error_build_parameter_string( $t_value );
				}
				echo '(', implode( $t_args, ', ' ), ' )', "\n";
			} else {
				echo "()\n";
			}
		}
	
		return;
	}

	echo '<div class="table-responsive">';
	echo '<table class="table table-bordered table-striped table-condensed">';
	echo '<tr><th>Filename</th><th>Line</th><th></th><th></th><th>Function</th><th>Args</th></tr>';

	# remove the call to the error handler from the stack trace

	foreach( $t_stack as $t_frame ) {
		echo '<tr>';
		echo '<td>', ( isset( $t_frame['file'] ) ? htmlentities( $t_frame['file'], ENT_COMPAT, 'UTF-8' ) : '-' ), '</td><td>', ( isset( $t_frame['line'] ) ? $t_frame['line'] : '-' ), '</td><td>', ( isset( $t_frame['class'] ) ? $t_frame['class'] : '-' ), '</td><td>', ( isset( $t_frame['type'] ) ? $t_frame['type'] : '-' ), '</td><td>', ( isset( $t_frame['function'] ) ? $t_frame['function'] : '-' ), '</td>';

		$t_args = array();
		if( isset( $t_frame['args'] ) && !empty( $t_frame['args'] ) ) {
			foreach( $t_frame['args'] as $t_value ) {
				$t_args[] = error_build_parameter_string( $t_value );
			}
			echo '<td>( ', htmlentities( implode( $t_args, ', ' ), ENT_COMPAT, 'UTF-8' ), ' )</td></tr>';
		} else {
			echo '<td>-</td></tr>';
		}
	}
	echo '</table>';
}

/**
 * Build a string describing the parameters to a function
 * @param string|array|object $p_param    Parameter.
 * @param boolean             $p_showtype Default true.
 * @param integer             $p_depth    Default 0.
 * @return string
 */
function error_build_parameter_string( $p_param, $p_showtype = true, $p_depth = 0 ) {
	if( $p_depth++ > 10 ) {
		return '<strong>***Nesting Level Too Deep***</strong>';
	}

	if( is_array( $p_param ) ) {
		$t_results = array();

		foreach( $p_param as $t_key => $t_value ) {
			$t_results[] = '[' . error_build_parameter_string( $t_key, false, $p_depth ) . '] => ' . error_build_parameter_string( $t_value, false, $p_depth );
		}

		return '<array> { ' . implode( $t_results, ', ' ) . ' }';
	} else if( is_object( $p_param ) ) {
		$t_results = array();

		$t_class_name = get_class( $p_param );
		$t_inst_vars = get_object_vars( $p_param );

		foreach( $t_inst_vars as $t_name => $t_value ) {
			$t_results[] = '[' . $t_name . '] => ' . error_build_parameter_string( $t_value, false, $p_depth );
		}

		return '<Object><' . $t_class_name . '> ( ' . implode( $t_results, ', ' ) . ' )';
	} else {
		if( $p_showtype ) {
			return '<' . gettype( $p_param ) . '>' . var_export( $p_param, true );
		} else {
			return var_export( $p_param, true );
		}
	}
}

/**
 * Return an error string (in the current language) for the given error.
 * @param integer $p_error Error string to localize.
 * @return string
 * @access public
 */
function error_string( $p_error ) {
	global $g_error_parameters;

	$t_lang = null;
	while( true ) {
		$t_err_msg = lang_get( 'MANTIS_ERROR', $t_lang );
		if( array_key_exists( $p_error, $t_err_msg ) ) {
			$t_error = $t_err_msg[$p_error];
			break;
		} elseif( is_null( $t_lang ) ) {
			# Error string not found, fall back to English
			$t_lang = 'english';
		} else {
			# Error string not found
			$t_error = lang_get( 'missing_error_string' );
			# Prepend the error number
			array_unshift( $g_error_parameters, $p_error );
			break;
		}
	}

	# We pad the parameter array to make sure that we don't get errors if
	#  the caller didn't give enough parameters for the error string
	$t_padding = array_pad( array(), 10, '' );

	# ripped from string_api
	$t_string = vsprintf( $t_error, array_merge( $g_error_parameters, $t_padding ) );
	return preg_replace( '/&amp;(#[0-9]+|[a-z]+);/i', '&$1;', @htmlspecialchars( $t_string, ENT_COMPAT, 'UTF-8' ) );
}

/**
 * Check if we have handled an error during this page
 * Return true if an error has been handled, false otherwise
 * @return boolean
 */
function error_handled() {
	global $g_error_handled;

	return( true == $g_error_handled );
}

/**
 * Set additional info parameters to be used when displaying the next error
 * This function takes a variable number of parameters
 *
 * When writing internationalized error strings, note that you can change the
 *  order of parameters in the string.  See the PHP manual page for the
 *  sprintf() function for more details.
 * @access public
 * @return void
 */
function error_parameters() {
	global $g_error_parameters;

	$g_error_parameters = func_get_args();
}

/**
 * Set a URL to give to the user to proceed after viewing the error
 * @access public
 * @param string $p_url URL given to user after viewing the error.
 * @return void
 */
function error_proceed_url( $p_url ) {
	global $g_error_proceed_url;

	$g_error_proceed_url = $p_url;
}