[apple/xnu.git] / libsa / bootstrap.cpp

/*
 * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
extern "C" {
#include <mach/kmod.h>
#include <libkern/kernel_mach_header.h>
#include <libkern/prelink.h>
}

#include <libkern/version.h>
#include <libkern/c++/OSContainers.h>
#include <libkern/OSKextLibPrivate.h>
#include <libkern/c++/OSKext.h>
#include <IOKit/IOLib.h>
#include <IOKit/IOService.h>
#include <IOKit/IODeviceTreeSupport.h>
#include <IOKit/IOCatalogue.h>

#if __x86_64__
#define KASLR_KEXT_DEBUG 0
#endif

#if PRAGMA_MARK
#pragma mark Bootstrap Declarations
#endif
/*********************************************************************
* Bootstrap Declarations
*
* The ENTIRE point of the libsa/KLD segment is to isolate bootstrap
* code from other parts of the kernel, so function symbols are not
* exported; rather pointers to those functions are exported.
*
* xxx - need to think about locking for handling the 'weak' refs.
* xxx - do export a non-KLD function that says you've called a
* xxx - bootstrap function that has been removed.
*
* ALL call-ins to this segment of the kernel must be done through
* exported pointers. The symbols themselves are private and not to
* be linked against.
*********************************************************************/
extern "C" {
    extern void (*record_startup_extensions_function)(void);
    extern void (*load_security_extensions_function)(void);
};

static void bootstrapRecordStartupExtensions(void);
static void bootstrapLoadSecurityExtensions(void);


#if NO_KEXTD
extern "C" bool IORamDiskBSDRoot(void);
#endif

#if PRAGMA_MARK
#pragma mark Macros
#endif
/*********************************************************************
* Macros
*********************************************************************/
#define CONST_STRLEN(str) (sizeof(str) - 1)

#if PRAGMA_MARK
#pragma mark Kernel Component Kext Identifiers
#endif
/*********************************************************************
* Kernel Component Kext Identifiers
*
* We could have each kernel resource kext automatically "load" as
* it's created, but it's nicer to have them listed in kextstat in
* the order of this list. We'll walk through this after setting up
* all the boot kexts and have them load up.
*********************************************************************/
static const char * sKernelComponentNames[] = {
   // The kexts for these IDs must have a version matching 'osrelease'.
   "com.apple.kernel",
   "com.apple.kpi.bsd",
   "com.apple.kpi.dsep",
   "com.apple.kpi.iokit",
   "com.apple.kpi.libkern",
   "com.apple.kpi.mach",
   "com.apple.kpi.private",
   "com.apple.kpi.unsupported",
   "com.apple.iokit.IONVRAMFamily",
   "com.apple.driver.AppleNMI",
   "com.apple.iokit.IOSystemManagementFamily",
   "com.apple.iokit.ApplePlatformFamily",
   NULL
};

#if PRAGMA_MARK
#pragma mark KLDBootstrap Class
#endif
/*********************************************************************
* KLDBootstrap Class
*
* We use a C++ class here so that it can be a friend of OSKext and
* get at private stuff. We can't hide the class itself, but we can
* hide the instance through which we invoke the functions.
*********************************************************************/
class KLDBootstrap {
    friend void bootstrapRecordStartupExtensions(void);
    friend void bootstrapLoadSecurityExtensions(void);

private:
    void readStartupExtensions(void);

    void readPrelinkedExtensions(
        kernel_section_t * prelinkInfoSect);
    void readBooterExtensions(void);
    
    OSReturn loadKernelComponentKexts(void);
    void     loadKernelExternalComponents(void);
    void     readBuiltinPersonalities(void);

    void     loadSecurityExtensions(void);
    
public:
    KLDBootstrap(void);
    ~KLDBootstrap(void);
};

static KLDBootstrap sBootstrapObject;

/*********************************************************************
* Set the function pointers for the entry points into the bootstrap
* segment upon C++ static constructor invocation.
*********************************************************************/
KLDBootstrap::KLDBootstrap(void)
{
    if (this != &sBootstrapObject) {
        panic("Attempt to access bootstrap segment.");
    }
    record_startup_extensions_function = &bootstrapRecordStartupExtensions;
    load_security_extensions_function = &bootstrapLoadSecurityExtensions;
}

/*********************************************************************
* Clear the function pointers for the entry points into the bootstrap
* segment upon C++ static destructor invocation.
*********************************************************************/
KLDBootstrap::~KLDBootstrap(void)
{
    if (this != &sBootstrapObject) {
        panic("Attempt to access bootstrap segment.");
    }


    record_startup_extensions_function = 0;
    load_security_extensions_function = 0;
}

/*********************************************************************
*********************************************************************/
void
KLDBootstrap::readStartupExtensions(void)
{
    kernel_section_t * prelinkInfoSect = NULL;  // do not free

    OSKextLog(/* kext */ NULL,
        kOSKextLogProgressLevel |
        kOSKextLogGeneralFlag | kOSKextLogDirectoryScanFlag |
        kOSKextLogKextBookkeepingFlag,
        "Reading startup extensions.");
    
   /* If the prelink info segment has a nonzero size, we are prelinked
    * and won't have any individual kexts or mkexts to read.
    * Otherwise, we need to read kexts or the mkext from what the booter
    * has handed us.
    */
    prelinkInfoSect = getsectbyname(kPrelinkInfoSegment, kPrelinkInfoSection);
    if (prelinkInfoSect->size) {
        readPrelinkedExtensions(prelinkInfoSect);
    } else {
        readBooterExtensions();
    }

    loadKernelComponentKexts();
    loadKernelExternalComponents();
    readBuiltinPersonalities();
    OSKext::sendAllKextPersonalitiesToCatalog();

    return;
}

/*********************************************************************
*********************************************************************/
void
KLDBootstrap::readPrelinkedExtensions(
    kernel_section_t * prelinkInfoSect)
{
    OSArray                   * infoDictArray           = NULL;  // do not release
    OSObject                  * parsedXML       = NULL;  // must release
    OSDictionary              * prelinkInfoDict         = NULL;  // do not release
    OSString                  * errorString             = NULL;  // must release
    OSKext                    * theKernel               = NULL;  // must release

    kernel_segment_command_t  * prelinkTextSegment      = NULL;  // see code
    kernel_segment_command_t  * prelinkInfoSegment      = NULL;  // see code

   /* We make some copies of data, but if anything fails we're basically
    * going to fail the boot, so these won't be cleaned up on error.
    */
    void                      * prelinkData             = NULL;  // see code
    vm_size_t                   prelinkLength           = 0;


    OSDictionary              * infoDict                = NULL;  // do not release

    IORegistryEntry           * registryRoot            = NULL;  // do not release
    OSNumber                  * prelinkCountObj         = NULL;  // must release

    u_int                       i = 0;
#if NO_KEXTD
    bool                        ramDiskBoot;
    bool                        developerDevice;
    bool                        dontLoad;
#endif

    OSKextLog(/* kext */ NULL,
        kOSKextLogProgressLevel |
        kOSKextLogDirectoryScanFlag | kOSKextLogArchiveFlag,
        "Starting from prelinked kernel.");

    prelinkTextSegment = getsegbyname(kPrelinkTextSegment);
    if (!prelinkTextSegment) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogDirectoryScanFlag | kOSKextLogArchiveFlag,
            "Can't find prelinked kexts' text segment.");
        goto finish;
    }

#if KASLR_KEXT_DEBUG
    unsigned long   scratchSize;
    vm_offset_t     scratchAddr;
    
    IOLog("kaslr: prelinked kernel address info: \n");
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__TEXT", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __TEXT \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__DATA", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __DATA \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__LINKEDIT", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __LINKEDIT \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__KLD", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __KLD \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__PRELINK_TEXT", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __PRELINK_TEXT \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
    
    scratchAddr = (vm_offset_t) getsegdatafromheader(&_mh_execute_header, "__PRELINK_INFO", &scratchSize);
    IOLog("kaslr: start 0x%lx end 0x%lx length %lu for __PRELINK_INFO \n", 
          (unsigned long)scratchAddr, 
          (unsigned long)(scratchAddr + scratchSize),
          scratchSize);
#endif

    prelinkData = (void *) prelinkTextSegment->vmaddr;
    prelinkLength = prelinkTextSegment->vmsize;


   /* Unserialize the info dictionary from the prelink info section.
    */
    parsedXML = OSUnserializeXML((const char *)prelinkInfoSect->addr,
        &errorString);
    if (parsedXML) {
        prelinkInfoDict = OSDynamicCast(OSDictionary, parsedXML);
    }
    if (!prelinkInfoDict) {
        const char * errorCString = "(unknown error)";
        
        if (errorString && errorString->getCStringNoCopy()) {
            errorCString = errorString->getCStringNoCopy();
        } else if (parsedXML) {
            errorCString = "not a dictionary";
        }
        OSKextLog(/* kext */ NULL, kOSKextLogErrorLevel | kOSKextLogArchiveFlag,
            "Error unserializing prelink plist: %s.", errorCString);
        goto finish;
    }

#if NO_KEXTD
    /* Check if we should keep developer kexts around.
     * TODO: Check DeviceTree instead of a boot-arg <rdar://problem/10604201>
     */
    developerDevice = true;
    PE_parse_boot_argn("developer", &developerDevice, sizeof(developerDevice));

    ramDiskBoot = IORamDiskBSDRoot();
#endif /* NO_KEXTD */

    infoDictArray = OSDynamicCast(OSArray, 
        prelinkInfoDict->getObject(kPrelinkInfoDictionaryKey));
    if (!infoDictArray) {
        OSKextLog(/* kext */ NULL, kOSKextLogErrorLevel | kOSKextLogArchiveFlag,
            "The prelinked kernel has no kext info dictionaries");
        goto finish;
    }
    
    /* Create dictionary of excluded kexts
     */
    OSKext::createExcludeListFromPrelinkInfo(infoDictArray);

    /* Create OSKext objects for each info dictionary. 
     */
    for (i = 0; i < infoDictArray->getCount(); ++i) {
        infoDict = OSDynamicCast(OSDictionary, infoDictArray->getObject(i));
        if (!infoDict) {
            OSKextLog(/* kext */ NULL,
                kOSKextLogErrorLevel |
                kOSKextLogDirectoryScanFlag | kOSKextLogArchiveFlag,
                "Can't find info dictionary for prelinked kext #%d.", i);
            continue;
        }

#if NO_KEXTD
        dontLoad = false;

        /* If we're not on a developer device, skip and free developer kexts.
         */
        if (developerDevice == false) {
            OSBoolean *devOnlyBool = OSDynamicCast(OSBoolean,
                infoDict->getObject(kOSBundleDeveloperOnlyKey));
            if (devOnlyBool == kOSBooleanTrue) {
                dontLoad = true;
            }
        }

        /* Skip and free kexts that are only needed when booted from a ram disk.
         */
        if (ramDiskBoot == false) {
            OSBoolean *ramDiskOnlyBool = OSDynamicCast(OSBoolean,
                infoDict->getObject(kOSBundleRamDiskOnlyKey));
            if (ramDiskOnlyBool == kOSBooleanTrue) {
                dontLoad = true;
            }
	}

        if (dontLoad == true) {
            OSString *bundleID = OSDynamicCast(OSString,
                infoDict->getObject(kCFBundleIdentifierKey));
            if (bundleID) {
                OSKextLog(NULL, kOSKextLogWarningLevel | kOSKextLogGeneralFlag,
                    "Kext %s not loading.", bundleID->getCStringNoCopy());
            }
            
            OSNumber *addressNum = OSDynamicCast(OSNumber,
                infoDict->getObject(kPrelinkExecutableLoadKey));
            OSNumber *lengthNum = OSDynamicCast(OSNumber,
                infoDict->getObject(kPrelinkExecutableSizeKey));
            if (addressNum && lengthNum) {
#error Pick the right way to free prelinked data on this arch
            }

            infoDictArray->removeObject(i--);
            continue;
        }
#endif /* NO_KEXTD */

       /* Create the kext for the entry, then release it, because the
        * kext system keeps them around until explicitly removed.
        * Any creation/registration failures are already logged for us.
        */
        OSKext * newKext = OSKext::withPrelinkedInfoDict(infoDict);
        OSSafeReleaseNULL(newKext);
    }
    
   /* Store the number of prelinked kexts in the registry so we can tell
    * when the system has been started from a prelinked kernel.
    */
    registryRoot = IORegistryEntry::getRegistryRoot();
    assert(registryRoot);

    prelinkCountObj = OSNumber::withNumber(
        (unsigned long long)infoDictArray->getCount(),
        8 * sizeof(uint32_t));
    assert(prelinkCountObj);
    if (prelinkCountObj) {
        registryRoot->setProperty(kOSPrelinkKextCountKey, prelinkCountObj);
    }

    OSKextLog(/* kext */ NULL,
        kOSKextLogProgressLevel |
        kOSKextLogGeneralFlag | kOSKextLogKextBookkeepingFlag |
        kOSKextLogDirectoryScanFlag | kOSKextLogArchiveFlag,
        "%u prelinked kexts", 
        infoDictArray->getCount());

#if CONFIG_KEXT_BASEMENT
        /* On CONFIG_KEXT_BASEMENT systems, kexts are copied to their own 
         * special VM region during OSKext init time, so we can free the whole 
         * segment now.
         */
        ml_static_mfree((vm_offset_t) prelinkData, prelinkLength);
#endif /* __x86_64__ */

   /* Free the prelink info segment, we're done with it.
    */
    prelinkInfoSegment = getsegbyname(kPrelinkInfoSegment);
    if (prelinkInfoSegment) {
        ml_static_mfree((vm_offset_t)prelinkInfoSegment->vmaddr,
            (vm_size_t)prelinkInfoSegment->vmsize);
    }

finish:
    OSSafeRelease(errorString);
    OSSafeRelease(parsedXML);
    OSSafeRelease(theKernel);
    OSSafeRelease(prelinkCountObj);
    return;
}

/*********************************************************************
*********************************************************************/
#define BOOTER_KEXT_PREFIX   "Driver-"

typedef struct _DeviceTreeBuffer {
    uint32_t paddr;
    uint32_t length;
} _DeviceTreeBuffer;

void
KLDBootstrap::readBooterExtensions(void)
{
    IORegistryEntry           * booterMemoryMap         = NULL;  // must release
    OSDictionary              * propertyDict            = NULL;  // must release
    OSCollectionIterator      * keyIterator             = NULL;  // must release
    OSString                  * deviceTreeName          = NULL;  // do not release
    
    const _DeviceTreeBuffer   * deviceTreeBuffer        = NULL;  // do not free
    char                      * booterDataPtr           = NULL;  // do not free
    OSData                    * booterData              = NULL;  // must release

    OSKext                    * aKext                   = NULL;  // must release

    OSKextLog(/* kext */ NULL,
        kOSKextLogProgressLevel |
        kOSKextLogDirectoryScanFlag | kOSKextLogKextBookkeepingFlag,
        "Reading startup extensions from booter memory.");
    
    booterMemoryMap = IORegistryEntry::fromPath( "/chosen/memory-map", gIODTPlane);

    if (!booterMemoryMap) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogGeneralFlag | kOSKextLogDirectoryScanFlag,
            "Can't read booter memory map.");
        goto finish;
    }

    propertyDict = booterMemoryMap->dictionaryWithProperties();
    if (!propertyDict) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogDirectoryScanFlag,
            "Can't get property dictionary from memory map.");
        goto finish;
    }

    keyIterator = OSCollectionIterator::withCollection(propertyDict);
    if (!keyIterator) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogGeneralFlag,
            "Can't allocate iterator for driver images.");
        goto finish;
    }

    /* Create dictionary of excluded kexts
     */
    OSKext::createExcludeListFromBooterData(propertyDict, keyIterator);
    keyIterator->reset();

    while ( ( deviceTreeName =
        OSDynamicCast(OSString, keyIterator->getNextObject() ))) {

        const char * devTreeNameCString = deviceTreeName->getCStringNoCopy();
        OSData * deviceTreeEntry = OSDynamicCast(OSData,
            propertyDict->getObject(deviceTreeName));

       /* Clear out the booterData from the prior iteration.
        */
        OSSafeReleaseNULL(booterData);

        /* If there is no entry for the name, we can't do much with it. */
        if (!deviceTreeEntry) {
            continue;
        }

        /* Make sure it is a kext */
        if (strncmp(devTreeNameCString,
                    BOOTER_KEXT_PREFIX,
                    CONST_STRLEN(BOOTER_KEXT_PREFIX))) {
            continue;
        }

        deviceTreeBuffer = (const _DeviceTreeBuffer *)
            deviceTreeEntry->getBytesNoCopy(0, sizeof(deviceTreeBuffer));
        if (!deviceTreeBuffer) {
           /* We can't get to the data, so we can't do anything,
            * not even free it from physical memory (if it's there).
            */
            OSKextLog(/* kext */ NULL,
                kOSKextLogErrorLevel |
                kOSKextLogDirectoryScanFlag,
                "Device tree entry %s has NULL pointer.",
                devTreeNameCString);
            goto finish;  // xxx - continue, panic?
        }

        booterDataPtr = (char *)ml_static_ptovirt(deviceTreeBuffer->paddr);
        if (!booterDataPtr) {
            OSKextLog(/* kext */ NULL,
                kOSKextLogErrorLevel |
                kOSKextLogDirectoryScanFlag,
                "Can't get virtual address for device tree entry %s.",
                devTreeNameCString);
            goto finish;
        }

       /* Wrap the booter data buffer in an OSData and set a dealloc function
        * so it will take care of the physical memory when freed. Kexts will
        * retain the booterData for as long as they need it. Remove the entry
        * from the booter memory map after this is done.
        */
        booterData = OSData::withBytesNoCopy(booterDataPtr,
            deviceTreeBuffer->length);
        if (!booterData) {
            OSKextLog(/* kext */ NULL,
                kOSKextLogErrorLevel |
                kOSKextLogGeneralFlag,
                "Error - Can't allocate OSData wrapper for device tree entry %s.",
                devTreeNameCString);
            goto finish;
        }
        booterData->setDeallocFunction(osdata_phys_free);

        /* Create the kext for the entry, then release it, because the
         * kext system keeps them around until explicitly removed.
         * Any creation/registration failures are already logged for us.
         */
        OSKext * newKext = OSKext::withBooterData(deviceTreeName, booterData);
        OSSafeRelease(newKext);

        booterMemoryMap->removeProperty(deviceTreeName);

    } /* while ( (deviceTreeName = OSDynamicCast(OSString, ...) ) ) */

finish:

    OSSafeRelease(booterMemoryMap);
    OSSafeRelease(propertyDict);
    OSSafeRelease(keyIterator);
    OSSafeRelease(booterData);
    OSSafeRelease(aKext);
    return;
}

/*********************************************************************
*********************************************************************/
#define COM_APPLE  "com.apple."

void
KLDBootstrap::loadSecurityExtensions(void)
{
    OSDictionary         * extensionsDict = NULL;  // must release
    OSCollectionIterator * keyIterator    = NULL;  // must release
    OSString             * bundleID       = NULL;  // don't release
    OSKext               * theKext        = NULL;  // don't release
    OSBoolean            * isSecurityKext = NULL;  // don't release

    OSKextLog(/* kext */ NULL,
        kOSKextLogStepLevel |
        kOSKextLogLoadFlag,
        "Loading security extensions.");

    extensionsDict = OSKext::copyKexts();
    if (!extensionsDict) {
        return;
    }

    keyIterator = OSCollectionIterator::withCollection(extensionsDict);
    if (!keyIterator) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogGeneralFlag,
            "Failed to allocate iterator for security extensions.");
        goto finish;
    }

    while ((bundleID = OSDynamicCast(OSString, keyIterator->getNextObject()))) {

        const char * bundle_id = bundleID->getCStringNoCopy();
        
       /* Skip extensions whose bundle IDs don't start with "com.apple.".
        */
        if (!bundle_id ||
            (strncmp(bundle_id, COM_APPLE, CONST_STRLEN(COM_APPLE)) != 0)) {

            continue;
        }

        theKext = OSDynamicCast(OSKext, extensionsDict->getObject(bundleID));
        if (!theKext) {
            continue;
        }

        isSecurityKext = OSDynamicCast(OSBoolean,
            theKext->getPropertyForHostArch(kAppleSecurityExtensionKey));
        if (isSecurityKext && isSecurityKext->isTrue()) {
            OSKextLog(/* kext */ NULL,
                kOSKextLogStepLevel |
                kOSKextLogLoadFlag,
                "Loading security extension %s.", bundleID->getCStringNoCopy());
            OSKext::loadKextWithIdentifier(bundleID->getCStringNoCopy(),
                /* allowDefer */ false);
        }
    }

finish:
    OSSafeRelease(keyIterator);
    OSSafeRelease(extensionsDict);

    return;
}

/*********************************************************************
* We used to require that all listed kernel components load, but
* nowadays we can get them from userland so we only try to load the
* ones we have. If an error occurs later, such is life.
*
* Note that we look the kexts up first, so we can avoid spurious
* (in this context, anyhow) log messages about kexts not being found.
*
* xxx - do we even need to do this any more? Check if the kernel
* xxx - compoonents just load in the regular paths
*********************************************************************/
OSReturn
KLDBootstrap::loadKernelComponentKexts(void)
{
    OSReturn      result      = kOSReturnSuccess;  // optimistic
    OSKext      * theKext     = NULL;              // must release
    const char ** kextIDPtr   = NULL;              // do not release

    for (kextIDPtr = &sKernelComponentNames[0]; *kextIDPtr; kextIDPtr++) {
        
        OSSafeReleaseNULL(theKext);
        theKext = OSKext::lookupKextWithIdentifier(*kextIDPtr);

        if (theKext) {
            if (kOSReturnSuccess != OSKext::loadKextWithIdentifier(
                *kextIDPtr, /* allowDefer */ false)) {

                // xxx - check KextBookkeeping, might be redundant
                OSKextLog(/* kext */ NULL,
                    kOSKextLogErrorLevel |
                    kOSKextLogDirectoryScanFlag | kOSKextLogKextBookkeepingFlag,
                    "Failed to initialize kernel component %s.", *kextIDPtr);
                result = kOSReturnError;
            }
        }
    }

    OSSafeRelease(theKext);
    return result;
}

/*********************************************************************
* Ensure that Kernel External Components are loaded early in boot,
* before other kext personalities get sent to the IOCatalogue. These
* kexts are treated specially because they may provide the implementation
* for kernel-vended KPI, so they must register themselves before
* general purpose IOKit probing begins.
*********************************************************************/

#define COM_APPLE_KEC  "com.apple.kec."

void
KLDBootstrap::loadKernelExternalComponents(void)
{
    OSDictionary         * extensionsDict = NULL;  // must release
    OSCollectionIterator * keyIterator    = NULL;  // must release
    OSString             * bundleID       = NULL;  // don't release
    OSKext               * theKext        = NULL;  // don't release
    OSBoolean            * isKernelExternalComponent = NULL;  // don't release

    OSKextLog(/* kext */ NULL,
        kOSKextLogStepLevel |
        kOSKextLogLoadFlag,
        "Loading Kernel External Components.");

    extensionsDict = OSKext::copyKexts();
    if (!extensionsDict) {
        return;
    }

    keyIterator = OSCollectionIterator::withCollection(extensionsDict);
    if (!keyIterator) {
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogGeneralFlag,
            "Failed to allocate iterator for Kernel External Components.");
        goto finish;
    }

    while ((bundleID = OSDynamicCast(OSString, keyIterator->getNextObject()))) {

        const char * bundle_id = bundleID->getCStringNoCopy();
        
       /* Skip extensions whose bundle IDs don't start with "com.apple.kec.".
        */
        if (!bundle_id ||
            (strncmp(bundle_id, COM_APPLE_KEC, CONST_STRLEN(COM_APPLE_KEC)) != 0)) {

            continue;
        }

        theKext = OSDynamicCast(OSKext, extensionsDict->getObject(bundleID));
        if (!theKext) {
            continue;
        }

        isKernelExternalComponent = OSDynamicCast(OSBoolean,
            theKext->getPropertyForHostArch(kAppleKernelExternalComponentKey));
        if (isKernelExternalComponent && isKernelExternalComponent->isTrue()) {
            OSKextLog(/* kext */ NULL,
                kOSKextLogStepLevel |
                kOSKextLogLoadFlag,
                "Loading kernel external component %s.", bundleID->getCStringNoCopy());
            OSKext::loadKextWithIdentifier(bundleID->getCStringNoCopy(),
                /* allowDefer */ false);
        }
    }

finish:
    OSSafeRelease(keyIterator);
    OSSafeRelease(extensionsDict);

    return;
}

/*********************************************************************
 *********************************************************************/
void
KLDBootstrap::readBuiltinPersonalities(void)
{
    OSObject              * parsedXML             = NULL;  // must release
    OSArray               * builtinExtensions     = NULL;  // do not release
    OSArray               * allPersonalities      = NULL;  // must release
    OSString              * errorString           = NULL;  // must release
    kernel_section_t      * infosect              = NULL;  // do not free
    OSCollectionIterator  * personalitiesIterator = NULL;  // must release
    unsigned int            count, i;
    
    OSKextLog(/* kext */ NULL,
        kOSKextLogStepLevel |
        kOSKextLogLoadFlag,
        "Reading built-in kernel personalities for I/O Kit drivers.");

   /* Look in the __BUILTIN __info segment for an array of Info.plist
    * entries. For each one, extract the personalities dictionary, add
    * it to our array, then push them all (without matching) to
    * the IOCatalogue. This can be used to augment the personalities
    * in gIOKernelConfigTables, especially when linking entire kexts into
    * the mach_kernel image.
    */
    infosect   = getsectbyname("__BUILTIN", "__info");
    if (!infosect) {
        // this isn't fatal
        goto finish;
    }
        
    parsedXML = OSUnserializeXML((const char *) (uintptr_t)infosect->addr,
        &errorString);
    if (parsedXML) {
        builtinExtensions = OSDynamicCast(OSArray, parsedXML);
    }
    if (!builtinExtensions) {
        const char * errorCString = "(unknown error)";
        
        if (errorString && errorString->getCStringNoCopy()) {
            errorCString = errorString->getCStringNoCopy();
        } else if (parsedXML) {
            errorCString = "not an array";
        }
        OSKextLog(/* kext */ NULL,
            kOSKextLogErrorLevel |
            kOSKextLogLoadFlag,
            "Error unserializing built-in personalities: %s.", errorCString);
        goto finish;
    }
            
    // estimate 3 personalities per Info.plist/kext
    count = builtinExtensions->getCount();
    allPersonalities = OSArray::withCapacity(count * 3);
            
    for (i = 0; i < count; i++) {
        OSDictionary            * infoDict = NULL;      // do not release
        OSString                * moduleName = NULL;    // do not release
        OSDictionary            * personalities;        // do not release
        OSString                * personalityName;      // do not release    
        
        OSSafeReleaseNULL(personalitiesIterator);

        infoDict = OSDynamicCast(OSDictionary,
            builtinExtensions->getObject(i));
        if (!infoDict) {
            continue;
        }
        
        moduleName = OSDynamicCast(OSString,
            infoDict->getObject(kCFBundleIdentifierKey));
        if (!moduleName) {
            continue;
        }
        
        OSKextLog(/* kext */ NULL,
            kOSKextLogStepLevel |
            kOSKextLogLoadFlag,
            "Adding personalities for built-in driver %s:",
            moduleName->getCStringNoCopy());
        
        personalities = OSDynamicCast(OSDictionary,
            infoDict->getObject("IOKitPersonalities"));
        if (!personalities) {
            continue;
        }
        
        personalitiesIterator = OSCollectionIterator::withCollection(personalities);
        if (!personalitiesIterator) {
            continue;  // xxx - well really, what can we do? should we panic?
        }
        
        while ((personalityName = OSDynamicCast(OSString,
            personalitiesIterator->getNextObject()))) {
            
            OSDictionary * personality = OSDynamicCast(OSDictionary,
                personalities->getObject(personalityName));

            OSKextLog(/* kext */ NULL,
                kOSKextLogDetailLevel |
                kOSKextLogLoadFlag,
                "Adding built-in driver personality %s.",
                personalityName->getCStringNoCopy());
        
			if (personality && !personality->getObject(kCFBundleIdentifierKey)) {
				personality->setObject(kCFBundleIdentifierKey, moduleName);
			}
            allPersonalities->setObject(personality);
        }
    }
    
    gIOCatalogue->addDrivers(allPersonalities, false);

finish:
    OSSafeRelease(parsedXML);
    OSSafeRelease(allPersonalities);
    OSSafeRelease(errorString);
    OSSafeRelease(personalitiesIterator);
    return;
}

#if PRAGMA_MARK
#pragma mark Bootstrap Functions
#endif
/*********************************************************************
* Bootstrap Functions
*********************************************************************/
static void bootstrapRecordStartupExtensions(void)
{
    sBootstrapObject.readStartupExtensions();
    return;
}

static void bootstrapLoadSecurityExtensions(void)
{
    sBootstrapObject.loadSecurityExtensions();
    return;
}