Parsing iOS watchdog 0x8badfood hang reports

During beta testing of [Loopy Pro](https://loopypro.com), a tester had the misfortune to come across a hang-on-launch bug of the “exhausted real (wall clock) time allowance” kind that I couldn’t reproduce at all.

Annoyingly, when that happens, iOS often produces an unusable “ips” crash log which doesn’t at all resemble the normal, symbolicate-able kind – it’s pretty much just bunch of JSON with very little helpful content.

I got desperate, and wrote a parser to convert that JSON log into the normal kind, which can be symbolicated by the tool provided by Apple (which lives at /Applications/Xcode.app/Contents/SharedFrameworks/DVTFoundation.framework/Versions/A/Resources/symbolicatecrash, by the way).

It’s just a quick-and-dirty PHP script, but it does the job, and I was finally able to see what was happening during the hang.

Here it is:

8badfood.php

#!/usr/local/bin/php
<?php
$file = file_get_contents("php://stdin");
$file = strstr($file, "\n");
$data = json_decode($file);
 
$images = $data->usedImages;
 
$header=<<<EOF
Incident Identifier: $data->incident
CrashReporter Key:   $data->incident
Hardware Model:      $data->modelCode
Process:             $data->procName [$data->pid]
Path:                $data->procPath
Identifier:          {$data->bundleInfo->CFBundleIdentifier}
Version:             {$data->bundleInfo->CFBundleShortVersionString} ({$data->bundleInfo->CFBundleVersion})
Code Type:           $data->cpuType (Native)
Role:                $data->procRole
Parent Process:      $data->parentProc [$data->parentPid]
Coalition:           $data->coalitionName [$data->pid]
 
Date/Time:           $data->captureTime
Launch Time:         $data->procLaunch
OS Version:          {$data->osVersion->train} ({$data->osVersion->build})
Release Type:        {$data->osVersion->releaseType}
Report Version:      104
 
EOF;
echo $header;
 
echo "\n" . join("\n", $data->termination->reasons) . "\n\n";
 
foreach ( $data->threads as $index => $thread ) {
	if ( isset($thread->queue) ) printf("Thread %d name:  %s\n", $index, "Dispatch Queue: ".$thread->queue);
	printf("Thread %d:\n", $index);
	foreach ( $thread->frames as $index => $frame ) {
		$image = $images[$frame->imageIndex];
		$symbol = isset($frame->symbol) ? $frame->symbol." + ".$frame->symbolLocation : sprintf("0x%08x + %d", $image->base, $frame->imageOffset);
		printf("%-4d %-38s0x%08x %s\n", $index, $image->name, $image->base+$frame->imageOffset, $symbol);
	}
	echo "\n";
}
 
 
echo "Binary Images:\n";
foreach ( $images as $image ) {
	printf("       0x%08x -        0x%08x %s %s  <%s> %s\n", $image->base, $image->base+$image->size-1, $image->name, $image->arch, str_replace("-", "", $image->uuid), $image->path);
}
echo "\nEOF\n\n";
?>