]> git.saurik.com Git - apple/xnu.git/blobdiff - libsa/bootstrap.cpp
xnu-3248.50.21.tar.gz
[apple/xnu.git] / libsa / bootstrap.cpp
index d32532f563b0969c2b4103189c2e7bab8a7b4990..02e5694d06241f4ddc42ad5f6f4dbd0f5bf9638f 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-#include <IOKit/IOLib.h>
+extern "C" {
 #include <mach/kmod.h>
-#include <libkern/c++/OSDictionary.h>
-
-#include <libsa/kext.h>
-#include <libsa/catalogue.h>
-#include <libsa/malloc.h>
-
-#include "kld_patch.h"
-
-/*****
- * This function is used by IOCatalogue to load a kernel
- * extension. libsa initially sets it to be a function
- * that uses libkld to load and link the extension from
- * within the kernel. Once the root filesystem is up,
- * this gets switch to the kmod_load_extension() function,
- * which merely queues the extension for loading by the
- * kmodload utility.
- */
-extern kern_return_t (*kmod_load_function)(char *extension_name);
-extern bool (*record_startup_extensions_function)(void);
-extern bool (*add_from_mkext_function)(OSData * mkext);
-extern void (*remove_startup_extension_function)(const char * name);
-
-/****
- * IOCatalogue uses this variable to make a few decisions
- * about loading and matching drivers.
- */
-extern int kernelLinkerPresent;
+#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();
-    ~KLDBootstrap();
+    KLDBootstrap(void);
+    ~KLDBootstrap(void);
 };
 
+static KLDBootstrap sBootstrapObject;
 
-static KLDBootstrap bootstrap_obj;
+/*********************************************************************
+* 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.");
+    }
 
-/* The constructor creates a lock and puts entries into a dispatch
- * table for functions used to record and load kmods.
- */
-KLDBootstrap::KLDBootstrap() {
 
-    malloc_init();
+    record_startup_extensions_function = 0;
+    load_security_extensions_function = 0;
+}
+
+/*********************************************************************
+*********************************************************************/
+void
+KLDBootstrap::readStartupExtensions(void)
+{
+    kernel_section_t * prelinkInfoSect = NULL;  // do not free
 
-    kmod_load_function = &load_kernel_extension;
+    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();
+    }
 
-    record_startup_extensions_function = &recordStartupExtensions;
-    add_from_mkext_function = &addExtensionsFromArchive;
-    remove_startup_extension_function = &removeStartupExtension;
+    loadKernelComponentKexts();
+    loadKernelExternalComponents();
+    readBuiltinPersonalities();
+    OSKext::sendAllKextPersonalitiesToCatalog();
 
-    kernelLinkerPresent = 1;
+    return;
 }
 
-/* The destructor frees all wired memory regions held
- * by libsa's malloc package and disposes of the lock.
- */
-KLDBootstrap::~KLDBootstrap() {
+/*********************************************************************
+*********************************************************************/
+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
 
-    kld_file_cleanup_all_resources();
+    kernel_segment_command_t  * prelinkTextSegment      = NULL;  // see code
+    kernel_segment_command_t  * prelinkInfoSegment      = NULL;  // see code
 
-   /* Dump all device-tree entries for boot drivers, and all
-    * info on startup extensions. The IOCatalogue will now
-    * get personalities from kextd.
+   /* 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.
     */
-    clearStartupExtensionsAndLoaderInfo();
+    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
 
-   /* Free all temporary malloc memory.
+    prelinkData = (void *) prelinkTextSegment->vmaddr;
+    prelinkLength = prelinkTextSegment->vmsize;
+
+
+   /* Unserialize the info dictionary from the prelink info section.
     */
-    malloc_reset();
+    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;
+}
+