/*

    File:       main.c

    Contains:   Main program for a Carbon pre-login launchd agent.

    Written by: DTS

    Copyright:  Copyright (c) 2007 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.

                ("Apple") in consideration of your agreement to the following

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                non-exclusive license, under Apple's copyrights in this

                original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or

                without modifications, in source and/or binary forms; provided

                that if you redistribute the Apple Software in its entirety and

                without modifications, you must retain this notice and the

                following text and disclaimers in all such redistributions of

                the Apple Software. Neither the name, trademarks, service marks

                or logos of Apple Inc. may be used to endorse or promote

                products derived from the Apple Software without specific prior

                written permission from Apple.  Except as expressly stated in

                this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any

                patent rights that may be infringed by your derivative works or

                by other works in which the Apple Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

                WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,

                MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING

                THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

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                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT,

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    Change History (most recent first):

$Log$

*/

#include <Carbon/Carbon.h>

#include <asl.h>

#include <sys/event.h>

/////////////////////////////////////////////////////////////////////

#pragma mark ***** Common Code

static aslclient    gASLClient;

static aslmsg       gASLMessage;

static void WaitForWindowServerSession(void)

    // This routine waits for the window server to register its per-session 

    // services in our session.  This code was necessary in various pre-release 

    // versions of Mac OS X 10.5, but it is not necessary on the final version. 

    // However, I've left it in, and the option to enable it, to give me the 

    // flexibility to test this edge case.

{

    CFDictionaryRef dict;

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "WaitForWindowServerSession begin");

    do {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Checking CGSessionCopyCurrentDictionary");

        dict = CGSessionCopyCurrentDictionary();

        if (dict == NULL) {

            (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "No session, sleeping");

            sleep(1);

        }

    } while (dict == NULL);

    if (dict != NULL) {

        CFRelease(dict);

    }

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "WaitForWindowServerSession end");

}

static void HandleSIGTERMFromRunLoop(CFFileDescriptorRef f, CFOptionFlags callBackTypes, void *info);

    // forward declaration

static void InstallHandleSIGTERMFromRunLoop(void)

    // This routine installs HandleSIGTERMFromRunLoop as a SIGTERM handler. 

    // The wrinkle is, HandleSIGTERMFromRunLoop is called from the runloop rather 

    // than as a signal handler.  This means that HandleSIGTERMFromRunLoop is not 

    // limited to calling just the miniscule set of system calls that are safe 

    // from a signal handler.

    // 

    // This routine leaks lots of stuff.  You're only expected to call it once, 

    // from the main thread of your program.

{

    static const CFFileDescriptorContext    kContext = { 0, NULL, NULL, NULL, NULL };

    sig_t                   sigErr;

    int                     kq;

    CFFileDescriptorRef     kqRef;

    CFRunLoopSourceRef      kqSource;

    struct kevent           changes;

    int                     changeCount;

    // Ignore SIGTERM.  Even though we've ignored the signal, the kqueue will 

    // still see it.

    sigErr = signal(SIGTERM, SIG_IGN);

    assert(sigErr != SIG_ERR);

    // Create a kqueue and configure it to listen for the SIGTERM signal.

    kq = kqueue();

    assert(kq >= 0);

    // Use the new-in-10.5 EV_RECEIPT flag to ensure that we get what we expect.

    EV_SET(&changes, SIGTERM, EVFILT_SIGNAL, EV_ADD | EV_RECEIPT, 0, 0, NULL);

    changeCount = kevent(kq, &changes, 1, &changes, 1, NULL);

    assert(changeCount == 1);           // check that we get an event back

    assert(changes.flags & EV_ERROR);   // and that it contains error information

    assert(changes.data == 0);          // with no error

    // Wrap the kqueue in a CFFileDescriptor (new in Mac OS X 10.5!).  Then 

    // create a run-loop source from the CFFileDescriptor and add that to the 

    // runloop.

    kqRef = CFFileDescriptorCreate(NULL, kq, true, HandleSIGTERMFromRunLoop, &kContext);

    assert(kqRef != NULL);

    kqSource = CFFileDescriptorCreateRunLoopSource(NULL, kqRef, 0);

    assert(kqSource != NULL);

    CFRunLoopAddSource(CFRunLoopGetCurrent(), kqSource, kCFRunLoopDefaultMode);

    CFFileDescriptorEnableCallBacks(kqRef, kCFFileDescriptorReadCallBack);

    // Clean up.  We can release kqSource and kqRef because they're all being 

    // kept live by the fact that the kqSource is added to the runloop.  We 

    // must not close kq because file descriptors are not reference counted 

    // and kqRef now 'owns' this descriptor.

    CFRelease(kqSource);

    CFRelease(kqRef);

}

/////////////////////////////////////////////////////////////////////

#pragma mark ***** Carbon-Specific Code

static void HandleSIGTERMFromRunLoop(CFFileDescriptorRef f, CFOptionFlags callBackTypes, void *info)

    // Called from the runloop when the process receives a SIGTERM.  We log 

    // this occurence (which is safe to do because we're not in an actual signal 

    // handler, courtesy of the 'magic' in InstallHandleSIGTERMFromRunLoop) 

    // and then tell the app to quit.

{

    #pragma unused(f)

    #pragma unused(callBackTypes)

    #pragma unused(info)

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Got SIGTERM");

    QuitApplicationEventLoop();

}

int main(int argc, char *argv[])

{

    OSStatus            err;

    int                 argIndex;

    Boolean             delay;

    Boolean             waitForWindowServerSession;

    Boolean             forceShow;

    Boolean             cleanExit;

    IBNibRef            nibRef;

    WindowRef           window;

    // Initialise our ASL state.

    gASLClient = asl_open(NULL, "PreLoginAgents", 0);

    assert(gASLClient != NULL);

    (void) asl_set_filter(gASLClient, ASL_FILTER_MASK_UPTO(ASL_LEVEL_INFO));

    gASLMessage = asl_new(ASL_TYPE_MSG);

    assert(gASLMessage != NULL);

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Start");

    // Parse our arguments.  We support arguments that allow you to turn off 

    // various special cases within the code.  This makes it easy to test whether 

    // the special cases are still required.

    delay = false;

    waitForWindowServerSession = false;

    forceShow = true;

    cleanExit = true;

    for (argIndex = 1; argIndex < argc; argIndex++) {

        if ( strcasecmp(argv[argIndex], "--nodelay") == 0 ) {

            delay = false;

        } else if ( strcasecmp(argv[argIndex], "--delay") == 0 ) {

            delay = true;

        } else if ( strcasecmp(argv[argIndex], "--nowait") == 0 ) {

            waitForWindowServerSession = false;

        } else if ( strcasecmp(argv[argIndex], "--wait") == 0 ) {

            waitForWindowServerSession = true;

        } else if ( strcasecmp(argv[argIndex], "--noforce") == 0 ) {

            forceShow = false;

        } else if ( strcasecmp(argv[argIndex], "--force") == 0 ) {

            forceShow = true;

        } else if ( strcasecmp(argv[argIndex], "--nocleanexit") == 0 ) {

            cleanExit = false;

        } else if ( strcasecmp(argv[argIndex], "--cleanexit") == 0 ) {

            cleanExit = true;

        } else {

            (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Unrecognised argument '%s'", argv[argIndex]);

        }

    }

    // Handle various options.

    if (waitForWindowServerSession) {

        WaitForWindowServerSession();

    } else {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Not waiting for CGSessionCopyCurrentDictionary");

    }

    if (delay) {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Delaying");

        sleep(3);

    } else {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Not delaying");

    }

    // Set up our UI.

    err = CreateNibReference(CFSTR("main"), &nibRef);

    assert(err == noErr);

    err = CreateWindowFromNib(nibRef, CFSTR("MainWindow"), &window);

    assert(err == noErr);

    DisposeNibReference(nibRef);

    // We have to set kHIWindowBitCanBeVisibleWithoutLogin to let the 

    // system know that we're not accidentally trying to display a window 

    // pre-login.

    //

    // Also, window is a utility window and, by default, these have the 

    // kWindowHideOnSuspendAttribute attribute set.  As our application is a 

    // UI element which never activates, and we want our panel to show regardless, 

    // we must clear kWindowHideOnSuspendAttribute.

    static const int    kAttributesToSet[] = {

        kHIWindowBitCanBeVisibleWithoutLogin, 

        0

    };

    static const int    kAttributesToClear[] = {

        kHIWindowBitHideOnSuspend, 

        0

    };

    err = HIWindowChangeAttributes(

        window,

        kAttributesToSet,

        kAttributesToClear

    );

    assert(err == noErr);

    // Due to a problem with the relationship between the UI frameworks and the 

    // window server <rdar://problem/5136400>, ShowWindow is not sufficient to 

    // show the window.  We also have to use BringToFront.

    ShowWindow(window);

    if (forceShow) {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Showing window with extreme prejudice");

        BringToFront(window);

    } else {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Showing window normally");

    }

    // Set up our SIGTERM handler.

    if (cleanExit) {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Installing SIGTERM handler");

        InstallHandleSIGTERMFromRunLoop();

    } else {

        (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Not installing SIGTERM handler");

    }

    // Go go gadget Carbon!

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "RunApplicationEventLoop");

    RunApplicationEventLoop();

    (void) asl_log(gASLClient, gASLMessage, ASL_LEVEL_INFO, "Stop");

    return EXIT_SUCCESS;

}