Get the actual home directory when running in the OS X sandbox

gistfile1.m

#import <unistd.h>
#import <pwd.h>

NSURL *_LLActualHomeDirectoryLocation(void) {
	static NSURL *homeDirectoryLocation = nil;
	
	static dispatch_once_t homeDirectoryLocationPredicate = 0;
	dispatch_once(&homeDirectoryLocationPredicate, ^ {
		uid_t uid = getuid();
		
		long bufferSize = sysconf(_SC_GETPW_R_SIZE_MAX);
		NSCParameterAssert(bufferSize != -1);
		
		char buffer[bufferSize];
		struct passwd pwd = {};
		struct passwd *result = NULL;
		
		int getpwError = getpwuid_r(uid, &pwd, buffer, bufferSize, &result);
		NSCParameterAssert(getpwError == 0 && result != NULL);
		
		const char *homeDirectoryPath = pwd.pw_dir;
		homeDirectoryLocation = [NSURL fileURLWithPath:@(homeDirectoryPath)];
	});
	
	return homeDirectoryLocation;
}