App/AppDelegate.m

/*
     File: AppDelegate.m
 Abstract: Main app controller.
  Version: 1.0
 
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 */
 
#import "AppDelegate.h"
 
#import "Common.h"
#import "HelperTool.h"
 
#include <ServiceManagement/ServiceManagement.h>
 
@interface AppDelegate () {
    AuthorizationRef    _authRef;
}
 
// for IB
 
@property (nonatomic, assign, readwrite) IBOutlet NSWindow *    window;
@property (nonatomic, assign, readwrite) IBOutlet NSTextView *  textView;
 
- (IBAction)installAction:(id)sender;
- (IBAction)getVersionAction:(id)sender;
- (IBAction)readLicenseAction:(id)sender;
- (IBAction)writeLicenseAction:(id)sender;
- (IBAction)bindAction:(id)sender;
 
// private stuff
 
@property (atomic, copy,   readwrite) NSData *                  authorization;
@property (atomic, strong, readwrite) NSXPCConnection *         helperToolConnection;
 
@end
 
@implementation AppDelegate
 
- (void)applicationDidFinishLaunching:(NSNotification *)note
{
    #pragma unused(note)
    OSStatus                    err;
    AuthorizationExternalForm   extForm;
    
    assert(self.window != nil);
 
    // Create our connection to the authorization system.
    //
    // If we can't create an authorization reference then the app is not going to be able
    // to do anything requiring authorization.  Generally this only happens when you launch
    // the app in some wacky, and typically unsupported, way.  In the debug build we flag that 
    // with an assert.  In the release build we continue with self->_authRef as NULL, which will 
    // cause all authorized operations to fail.
    
    err = AuthorizationCreate(NULL, NULL, 0, &self->_authRef);
    if (err == errAuthorizationSuccess) {
        err = AuthorizationMakeExternalForm(self->_authRef, &extForm);
    }
    if (err == errAuthorizationSuccess) {
        self.authorization = [[NSData alloc] initWithBytes:&extForm length:sizeof(extForm)];
    }
    assert(err == errAuthorizationSuccess);
    
    // If we successfully connected to Authorization Services, add definitions for our default 
    // rights (unless they're already in the database).
    
    if (self->_authRef) {
        [Common setupAuthorizationRights:self->_authRef];
    }
    
    [self.window makeKeyAndOrderFront:self];
}
 
- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)sender
{
    #pragma unused(sender)
    return YES;
}
 
- (void)logText:(NSString *)text
    // Logs the specified text to the text view.
{
    // any thread
    assert(text != nil);
    [[NSOperationQueue mainQueue] addOperationWithBlock:^{
        [[self.textView textStorage] appendAttributedString:[[NSAttributedString alloc] initWithString:text]];
    }];
}
 
- (void)logWithFormat:(NSString *)format, ...
    // Logs the formatted text to the text view.
{
    va_list ap;
 
    // any thread
    assert(format != nil);
 
    va_start(ap, format);
    [self logText:[[NSString alloc] initWithFormat:format arguments:ap]];
    va_end(ap);
}
 
- (void)logError:(NSError *)error
    // Logs the error to the text view.
{
    // any thread
    assert(error != nil);
    [self logWithFormat:@"error %@ / %d\n", [error domain], (int) [error code]];
}
 
- (void)connectToHelperTool
    // Ensures that we're connected to our helper tool.
{
    assert([NSThread isMainThread]);
    if (self.helperToolConnection == nil) {
        self.helperToolConnection = [[NSXPCConnection alloc] initWithMachServiceName:kHelperToolMachServiceName options:NSXPCConnectionPrivileged];
        self.helperToolConnection.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(HelperToolProtocol)];
        #pragma clang diagnostic push
        #pragma clang diagnostic ignored "-Warc-retain-cycles"
        // We can ignore the retain cycle warning because a) the retain taken by the
        // invalidation handler block is released by us setting it to nil when the block 
        // actually runs, and b) the retain taken by the block passed to -addOperationWithBlock: 
        // will be released when that operation completes and the operation itself is deallocated 
        // (notably self does not have a reference to the NSBlockOperation).
        self.helperToolConnection.invalidationHandler = ^{
            // If the connection gets invalidated then, on the main thread, nil out our
            // reference to it.  This ensures that we attempt to rebuild it the next time around.
            self.helperToolConnection.invalidationHandler = nil;
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                self.helperToolConnection = nil;
                [self logText:@"connection invalidated\n"];
            }];
        };
        #pragma clang diagnostic pop
        [self.helperToolConnection resume];
    }
}
 
- (void)connectAndExecuteCommandBlock:(void(^)(NSError *))commandBlock
    // Connects to the helper tool and then executes the supplied command block on the 
    // main thread, passing it an error indicating if the connection was successful.
{
    assert([NSThread isMainThread]);
    
    // Ensure that there's a helper tool connection in place.
    
    [self connectToHelperTool];
 
    // Run the command block.  Note that we never error in this case because, if there is 
    // an error connecting to the helper tool, it will be delivered to the error handler 
    // passed to -remoteObjectProxyWithErrorHandler:.  However, I maintain the possibility 
    // of an error here to allow for future expansion.
 
    commandBlock(nil);
}
 
#pragma mark * IB Actions
 
- (IBAction)installAction:(id)sender
    // Called when the user clicks the Install button.  This uses SMJobBless to install 
    // the helper tool.
{
    #pragma unused(sender)
 
    Boolean             success;
    CFErrorRef          error;
    
    success = SMJobBless(
        kSMDomainSystemLaunchd,
        CFSTR("com.example.apple-samplecode.EBAS.HelperTool"),
        self->_authRef,
        &error
    );
 
    if (success) {
        [self logWithFormat:@"success\n"];
    } else {
        [self logError:(__bridge NSError *) error];
        CFRelease(error);
    }
}
 
- (IBAction)getVersionAction:(id)sender
    // Called when the user clicks the Get Version button.  This is the simplest form of
    // NSXPCConnection request because it doesn't require any authorization.
{
    #pragma unused(sender)
    [self connectAndExecuteCommandBlock:^(NSError * connectError) {
        if (connectError != nil) {
            [self logError:connectError];
        } else {
            [[self.helperToolConnection remoteObjectProxyWithErrorHandler:^(NSError * proxyError) {
                [self logError:proxyError];
            }] getVersionWithReply:^(NSString *version) {
                [self logWithFormat:@"version = %@\n", version];
            }];
        }
    }];
}
 
- (IBAction)readLicenseAction:(id)sender
    // Called when the user clicks the Read License button.  This is an example of an
    // authorized command that, by default, can be done by anyone.
{
    #pragma unused(sender)
    [self connectAndExecuteCommandBlock:^(NSError * connectError) {
        if (connectError != nil) {
            [self logError:connectError];
        } else {
            [[self.helperToolConnection remoteObjectProxyWithErrorHandler:^(NSError * proxyError) {
                [self logError:proxyError];
            }] readLicenseKeyAuthorization:self.authorization withReply:^(NSError * commandError, NSString * licenseKey) {
                if (commandError != nil) {
                    [self logError:commandError];
                } else {
                    [self logWithFormat:@"license = %@\n", licenseKey];
                }
            }];
        }
    }];
}
 
- (IBAction)writeLicenseAction:(id)sender
    // Called when the user clicks the Write License button.  This is an example of an
    // authorized command that, by default, can only be done by administrators.
{
    #pragma unused(sender)
    NSString *  licenseKey;
    
    // Generate a new random license key so that we can see things change.
    
    licenseKey = [[NSUUID UUID] UUIDString];
 
    [self connectAndExecuteCommandBlock:^(NSError * connectError) {
        if (connectError != nil) {
            [self logError:connectError];
        } else {
            [[self.helperToolConnection remoteObjectProxyWithErrorHandler:^(NSError * proxyError) {
                [self logError:proxyError];
            }] writeLicenseKey:licenseKey authorization:self.authorization withReply:^(NSError *error) {
                if (error != nil) {
                    [self logError:error];
                } else {
                    [self logWithFormat:@"success\n"];
                }
            }];
        }
    }];
}
 
- (IBAction)bindAction:(id)sender
    // Called when the user clicks the Bind button.  This is an example of an authorized
    // command that returns file descriptors.
{
    #pragma unused(sender)
    [self connectAndExecuteCommandBlock:^(NSError * connectError) {
        if (connectError != nil) {
            [self logError:connectError];
        } else {
            [[self.helperToolConnection remoteObjectProxyWithErrorHandler:^(NSError * proxyError) {
                [self logError:proxyError];
            }] bindToLowNumberPortAuthorization:self.authorization withReply:^(NSError *error, NSFileHandle *ipv4Handle, NSFileHandle *ipv6Handle) {
                if (error != nil) {
                    [self logError:error];
                } else {
                    // Each of these NSFileHandles has the close-on-dealloc flag set.  If we wanted to hold
                    // on to the underlying descriptor for a long time, we need to call <x-man-page://dup2>
                    // on that descriptor to get our our descriptor that persists beyond the lifetime of
                    // the NSFileHandle.  In this example app, however, we just print the descriptors, which
                    // we can do without any complications.
                    [self logWithFormat:@"IPv4 = %d, IPv6 = %u\n",
                        [ipv4Handle fileDescriptor],
                        [ipv6Handle fileDescriptor]
                    ];
                }
            }];
        }
    }];
}
 
@end