Source

MYUtilities / ExceptionUtils.m

//
//  ExceptionUtils.m
//  MYUtilities
//
//  Created by Jens Alfke on 1/5/08.
//  Copyright 2008 Jens Alfke. All rights reserved.
//  See BSD license at bottom of file.
//

#import "ExceptionUtils.h"

#import "Logging.h"
#import "Test.h"

#include <sys/sysctl.h>
#include <unistd.h>


#ifndef Warn
#define Warn NSLog
#endif


static void (*sExceptionReporter)(NSException*);

void MYSetExceptionReporter( void (*reporter)(NSException*) )
{
    sExceptionReporter = reporter;
}

void MYReportException( NSException *x, NSString *where, ... )
{
    va_list args;
    va_start(args,where);
    where = [[NSString alloc] initWithFormat: where arguments: args];
    va_end(args);
    Warn(@"Exception caught in %@:\n\t%@\n%@",where,x,x.my_callStack);
    if( sExceptionReporter )
        sExceptionReporter(x);
    [where release];
}


@implementation NSException (MYUtilities)


- (NSArray*) my_callStackReturnAddresses
{
    // On 10.5 or later, can get the backtrace:
    if( [self respondsToSelector: @selector(callStackReturnAddresses)] )
        return [self valueForKey: @"callStackReturnAddresses"];
    else
        return nil;
}

- (NSArray*) my_callStackReturnAddressesSkipping: (unsigned)skip limit: (unsigned)limit
{
    NSArray *addresses = [self my_callStackReturnAddresses];
    if( addresses ) {
        unsigned n = (unsigned) [addresses count];
        skip = MIN(skip,n);
        limit = MIN(limit,n-skip);
        addresses = [addresses subarrayWithRange: NSMakeRange(skip,limit)];
    }
    return addresses;
}


- (NSString*) my_callStack
{
    NSArray *addresses = [self my_callStackReturnAddressesSkipping: 1 limit: 15];
    if (!addresses)
        return nil;
    
    FILE *file = NULL;
#if !TARGET_OS_IPHONE
    // We pipe the hex return addresses through the 'atos' tool to get symbolic names:
    // Adapted from <http://paste.lisp.org/display/47196>:
    NSMutableString *cmd = [NSMutableString stringWithFormat: @"/usr/bin/atos -p %d", getpid()];
    NSValue *addr;
    foreach(addr,addresses) {
        [cmd appendFormat: @" %p", [addr pointerValue]];
    }
    file = popen( [cmd UTF8String], "r" );
#endif
    
    NSMutableString *result = [NSMutableString string];
    if( file ) {
        NSMutableData *output = [NSMutableData data];
        char buffer[512];
        size_t length;
        while ((length = fread( buffer, 1, sizeof( buffer ), file ) ))
            [output appendBytes: buffer length: length];
        pclose( file );
        NSString *outStr = [[[NSString alloc] initWithData: output encoding: NSUTF8StringEncoding] autorelease];
        
        NSString *line;
        foreach( line, [outStr componentsSeparatedByString: @"\n"] ) {
            // Skip  frames that are part of the exception/assertion handling itself:
            if( [line hasPrefix: @"-[NSAssertionHandler"] || [line hasPrefix: @"+[NSException"] 
                    || [line hasPrefix: @"-[NSException"] || [line hasPrefix: @"_AssertFailed"]
                    || [line hasPrefix: @"objc_"] )
                continue;
            if( result.length )
                [result appendString: @"\n"];
            [result appendString: @"\t"];
            [result appendString: line];
            // Don't show the "__start" frame below "main":
            if( [line hasPrefix: @"main "] )
                break;
        }
    } else {
        NSValue *addr;
        foreach(addr,addresses) {
            if( result.length )
                [result appendString: @" <- "];
            [result appendFormat: @"%p", [addr pointerValue]];
        }
    }
    return result;
}

@end




#ifdef NSAppKitVersionNumber10_4 // only enable this in a project that uses AppKit

@implementation MYExceptionReportingApplication


static void report( NSException *x ) {
    [NSApp reportException: x];
}

- (id) init
{
    self = [super init];
    if (self != nil) {
        MYSetExceptionReporter(&report);
    }
    return self;
}


- (void)reportException:(NSException *)x
{
    [super reportException: x];
    [self performSelector: @selector(_showExceptionAlert:) withObject: x afterDelay: 0.0];
    MYSetExceptionReporter(NULL);     // ignore further exceptions till alert is dismissed
}

- (void) _showExceptionAlert: (NSException*)x
{
    NSString *stack = [x my_callStack] ?:@"";
    NSInteger r = NSRunCriticalAlertPanel( @"Internal Error!",
                            [NSString stringWithFormat: @"Uncaught exception: %@\n%@\n\n%@\n\n"
                             "Please report this bug (you can copy & paste the text).",
                             [x name], [x reason], stack],
                            @"Continue",@"Quit",nil);
    if( r == NSAlertAlternateReturn )
        exit(1);
    MYSetExceptionReporter(&report);
}

@end

#endif



BOOL IsGDBAttached( void )
{
    // From: <http://lists.apple.com/archives/Xcode-users/2004/Feb/msg00241.html>
    int mib[4];
    size_t bufSize = 0;
    struct kinfo_proc kp;
    
    mib[0] = CTL_KERN;
    mib[1] = KERN_PROC;
    mib[2] = KERN_PROC_PID;
    mib[3] = getpid();
    
    bufSize = sizeof (kp);
    if (sysctl(mib, 4, &kp, &bufSize, NULL, 0) < 0) {
        Warn(@"Error %i calling sysctl",errno);
        return NO;
    }
    return (kp.kp_proc.p_flag & P_TRACED) != 0;
}



/*
 Copyright (c) 2008, Jens Alfke <jens@mooseyard.com>. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted
 provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright notice, this list of conditions
 and the following disclaimer.
 * 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.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRI-
 BUTORS 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.
 */
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