Mac OS X Internals: A Systems Approach

bsd/

The BSD kernel

config/

Lists of per-subsystem exported functions, property list files for pseudo-extensions

iokit/

The I/O Kit kernel runtime

libkern/

The kernel library

libsa/

The stand-alone library

osfmk/

The Mach kernel

pexpert/

The Platform Expert

bsd/bsm/

Basic Security Module (BSM) headers used by the kernel's auditing mechanism. BSM is both a security audit format and an API used to track security-related events in the operating system.

bsd/crypto/

Various cipher and hash implementations: AES (Rijndael), Blowfish, CAST-128, DES, MD5, RC4, SHA-1, and SHA-2.

bsd/dev/memdev.c

A RAM disk driver (for /dev/mdX devices).

bsd/dev/ppc/

BSD drivers for entities such as /dev/console, /dev/mem, /dev/kmem, /dev/null, /dev/zero, and a BSD driver wrapper for the NVRAM. The latter calls Platform Expert functions to perform the actual work. The BSD device switch tables for block and character devices are also initialized here. Also present are some machine-dependent functions used in the BSD subsystem, such as unix_syscall(), unix_syscall_return(), ppc_gettimeofday(), and signal-handling functions.

bsd/dev/random/

An implementation of the Yarrow^[a] pseudorandom number generator (PRNG) and the /dev/random device.

bsd/dev/unix_startup.c

Functions that initialize various BSD-related data structures during system startup.

bsd/dev/vn/

The vnode disk driver, which provides block and character interfaces to a vnode, allowing files to be treated as disks. The /usr/libexec/vndevice utility is used to control the driver.

bsd/hfs/

The HFS and HFS Plus file systems.

bsd/isofs/

The ISO 9660 file system for read-only optical discs.

bsd/kern/

The core of xnu's BSD component. It contains implementations of asynchronous I/O calls, the kauth mechanism, the audit mechanism, process-related system calls, sysctl calls, POSIX IPC, System V IPC, the unified buffer cache, sockets, mbufs, and various other system calls.

bsd/libkern/

Utility routines such as bcd(), bcmp(), inet_ntoa(), rindex(), and strtol().

bsd/miscfs/

Miscellaneous file systems: the dead file system for vnodes whose underlying file system has been dissociated (deadfs), the device file system (devfs), the file descriptor file system (fdesc), the fifo file system (fifofs), the null mount file system (nullfs), the file system for device-special files (specfs), the in-memory synthfs used for synthesizing mount points, the union mount file system (union), and the volume ID file system (volfs).

bsd/net/

Networking: the Berkeley packet filter (BPF), bridging, data link interface layer (DLIL), Ethernet, ARP, PPP, routing, IEEE 802.1q (VLAN), IEEE 802.3ad (Link Aggregation), etc.

bsd/netat/

AppleTalk Networking.

bsd/netinet/

IPv4 Networking: BOOTP, DHCP, ICMP, TCP, UDP, IP, the "dummynet" bandwidth limiter, and divert sockets.

bsd/netinet6/

IPv6 Networking.

bsd/netkey/

PF_KEY Key Management API (RFC 2367).

bsd/nfs/

NFS client and the kernel portion of the NFS server.

bsd/ufs/

An implementation of UFS based on the fast file system (ffs).

bsd/uxkern/

A Mach exception handler that translates Mach exceptions into Unix signals.

bsd/vfs/

The BSD virtual file system layer.

bsd/vm/

Vnode pager (swap to/from vnodes, demand paging from files), shared memory server calls.

iokit/Drivers/platform/

Implementations of I/O Kit classes listed in the KernelConfigTables arraye.g., AppleCPU, AppleNMI, and AppleNVRAM. As we will see in Chapter 10, the I/O Catalog is initialized with the contents of this array.

iokit/Families/IONVRAM/

Subclass of the NVRAM controller classsimply calls the Platform Expert to register the NVRAM controller, which publishes the "IONVRAM" resource in the I/O Kit.

iokit/Families/IOSystemManagement/

Watchdog timer.

iokit/IOKit/

I/O Kit header files.

iokit/Kernel/

Implementations of core I/O Kit classes and utility functions.

iokit/KernelConfigTables.cpp

Declarations of the list of "fake" kernel extensions and the KernelConfigTables array.

iokit/bsddev/

Support functions for BSDe.g., the di_root_image() netboot hook called by BSD to mount a disk image as the root device, and several other functions used by BSD while searching for a root device.

libkern/c++/

Implementations of various libkern classes (see Table 65).

libkern/gen/

High-level-language wrappers around assembly functions for atomic operations, miscellaneous debugging functions.

libkern/kmod/

Start and stop routines for the kernel's C++ and C language runtime environments.

libkern/libkern/

libkern header files.

libkern/mach-o/

A header describing the format of Mach-O files (loader.h), and another header containing definitions for accessing Mach-O headers (mach_header.h).

libkern/ppc/

Implementations of PowerPC-specific bcmp(), memcmp(), strlen(), and atomic increment/decrement functions.

libkern/stdio/

An implementation of scanf().

libkern/uuid/

Routines for parsing and generating universally unique identifiers (UUIDs) based on the first Ethernet device's hardware address and the current time.

Base and Abstract Classes

OSObject

The abstract base class for the Mac OS X kernel. It derives from the true root class OSMetaClassBase. It implements basic functionality such as allocation primitives, reference counting, and type-safe object casting.

OSMetaClass

A peer class to OSObject. It derives from the true root class OSMetaClassBase. An instance of this class represents one class that is known by the I/O Kit's RTTI system.

OSCollection

The abstract superclass for all collections.

OSIterator

The abstract superclass for iterator classes.

Collection Classes

OSArray

A class for maintaining lists of object references.

OSDictionary

A class for maintaining dictionaries of object references.

OSOrderedSet

A class for maintaining and sorting sets of OSMetaClassBase-derived objects.

OSSet

A class for storing OSMetaClassBase-derived objects.

OSCollectionIterator

A class that provides a mechanism to iterate over OSCollection-derived collections.

Container Classes

OSBoolean

A class for Boolean values.

OSData

A class for managing byte arrays.

OSNumber

A class for numeric values.

OSString

A class for managing strings.

OSSymbol

A class for representing unique string values.

OSSerialize

A class used by the container classes to serialize their instance data.

OSUnserializeXML

A class that recreates a container object from its serialized instance data in an XML buffer.

libsa/bootstrap.cpp

Constructor and destructor functions for libsa.

libsa/bsearch.c, libsa/dgraph.c, libsa/sort.c

Functions for binary searching, directed graphs, and heap sortused for supporting kernel extension loading.

libsa/c++rem3.c

Symbol remangler for code compiled with version 2.95 of the GNU C++ compilerinvoked during symbol table parsing when a Mach-O object file (typically a kernel extension) is mapped.

libsa/catalogue.cpp

I/O Catalog routines, such as those for accessing and manipulating kernel extension dictionaries, accessing mkext caches, and recording boot-time kernel extensions into dictionaries.

libsa/kext.cpp, libsa/kld_patch.c, libsa/kmod.cpp, libsa/load.c

The core of libsa's functionality: routines for resolving kernel extension dependencies, retrieving kernel extension versions, loading kernel extensions, patching vtables, etc.

libsa/malloc.c

Simple implementations of malloc() and realloc().

libsa/mkext.c

Routines for LZSS compression/decompression, and for computing 32-bit Adler checksums.

libsa/strrchr.c, libsa/strstr.c

String functions.

libsa/vers_rsrc.c

Routines for parsing and generating version strings.

osfmk/UserNotification/

Kernel portion of the Kernel User Notification Center (KUNC) mechanism, which can be used by software running in the kernel to execute user-space programs and to display notices or alert messages. The /usr/libexec/kuncd daemon is the user-space agent that processes such requests from the kernel.

osfmk/console/i386/

VGA text console, x86 serial console.

osfmk/console/iso_font.c

Data for the ISO Latin-1 font.

osfmk/console/panic_dialog.c

Panic user-interface routines, including routines for drawing, managing, and testing the panic dialog.

osfmk/console/panic_image.c

Pixel data for the default panic imagean 8-bit, 472x255 image.

osfmk/console/panic_ui/

Panic image files and utilities to convert them into a kernel-usable format.

osfmk/console/ppc/

Fast video scrolling, PowerPC serial console.

osfmk/console/rendered_numbers.c

Pixel data for hexadecimal digits 0 through F and the colon character.

osfmk/console/video_console.c

Hardware-independent portion of the video console.

osfmk/ddb/

Built-in kernel debugger.

osfmk/default_pager/

Default pager, including the back-end for managing swap files.

osfmk/device/

Mach support for the I/O Kit, including device representation through Mach ports. The I/O Kit master port is also set here.

osfmk/ipc/

The core of Mach's IPC facility implementation.

osfmk/kdp/

A kernel debugging protocol called KDP that uses a TFTP-like UDP-based transfer mechanism.

osfmk/kern/

The core Mach kernel: implementations of abstractions such as processors, processor sets, tasks, threads, memory allocation, and timers. IPC interfaces are also implemented here.

osfmk/mach/

Mach headers and MIG definition files.

osfmk/mach-o/

Functions for accessing Mach-O headers.

osfmk/mach_debug/

Mach debugging headers and MIG definition files.

osfmk/machine/

Headers that are wrappers for machine-dependent headers.

osfmk/ppc/

PowerPC-specific code: machine startup, exception vectors, trap handling, low-level context-switching code, low-level memory management, diagnostic calls, Classic support functions, machine-dependent debugger components, virtual machine monitor, kernel components for Apple's CHUD Tools, etc.

osfmk/profiling/

Kernel profiling support, which must be explicitly compiled in. The kgmon utility is used to control the profiling mechanism: It can stop or start the collection of kernel profiling data, dump the contents of the profile buffers, reset all the profile buffers, and retrieve specific named values from the kernel.

osfmk/sys/

Miscellaneous headers.

osfmk/vm/

Mach virtual memory subsystem, including the in-kernel shared memory server.

pexpert/gen/bootargs.c

Boot-argument parsing routines.

pexpert/gen/device_tree.c

Routines for accessing device tree entries and their properties.

pexpert/gen/pe_gen.c

Miscellaneous functions, including an 8-bit color lookup table used during bootstrapping.

pexpert/i386/

Machine identification, debugging output support, keyboard driver, generic interrupt handler, polled-mode serial port driver, and other platform-dependent routines such as for reading the timestamp counter, setting and clearing interrupts, generating a fake device tree, etc.

pexpert/pexpert/

Miscellaneous platform headers, including those containing image data for the rotating gearwheel image shown at startup to indicate boot progress.

pexpert/ppc/

Machine identification, debugging output support, clock speed determination by running timed loops, timebase value retrieval, and other platform functions.