libkern/libkern/OSKextLib.h

   1 /*
   2  * Copyright (c) 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #ifndef _LIBKERN_OSKEXTLIB_H
  30 #define _LIBKERN_OSKEXTLIB_H
  31
  32 #include <sys/cdefs.h>
  33 __BEGIN_DECLS
  34
  35 #include <stdint.h>
  36 #include <mach/kmod.h>
  37 #include <mach/vm_types.h>
  38
  39 #ifdef KERNEL
  40 #include <libkern/OSTypes.h>
  41 #include <libkern/OSReturn.h>
  42 #else
  43 #include <CoreFoundation/CoreFoundation.h>
  44 #include <System/libkern/OSReturn.h>
  45 #endif /* KERNEL */
  46
  47 /*!
  48  * @header
  49  *
  50  * Declares functions, basic return values, and other constants
  51  * related to kernel extensions (kexts).
  52  */
  53
  54 #if PRAGMA_MARK
  55 #pragma mark -
  56 /********************************************************************/
  57 #pragma mark OSReturn Values for Kernel Extensions
  58 /********************************************************************/
  59 #endif
  60 /*!
  61  * @group OSReturn Values for Kernel Extensions
  62  * Many kext-related functions return these values,
  63  * as well as those defined under
  64  * <code>@link //apple_ref/c/tdef/OSReturn OSReturn@/link</code>
  65  * and other variants of <code>kern_return_t</code>.
  66  */
  67
  68 #ifdef XNU_KERNEL_PRIVATE
  69 /*********************************************************************
  70 * Check libsyscall/mach/err_libkern.sub when editing or adding
  71 * result codes!
  72 *********************************************************************/
  73 #endif /* XNU_KERNEL_PRIVATE */
  74
  75 #define sub_libkern_kext           err_sub(2)
  76 #define libkern_kext_err(code)     (sys_libkern|sub_libkern_kext|(code))
  77
  78
  79 /*!
  80  * @define   kOSKextReturnInternalError
  81  * @abstract An internal error in the kext library.
  82  *           Contrast with <code>@link //apple_ref/c/econst/OSReturnError
  83  *           OSReturnError@/link</code>.
  84  */
  85 #define kOSKextReturnInternalError                   libkern_kext_err(0x1)
  86
  87 /*!
  88  * @define   kOSKextReturnNoMemory
  89  * @abstract Memory allocation failed.
  90  */
  91 #define kOSKextReturnNoMemory                        libkern_kext_err(0x2)
  92
  93 /*!
  94  * @define   kOSKextReturnNoResources
  95  * @abstract Some resource other than memory (such as available load tags)
  96  *           is exhausted.
  97  */
  98 #define kOSKextReturnNoResources                     libkern_kext_err(0x3)
  99
 100 /*!
 101  * @define   kOSKextReturnNotPrivileged
 102  * @abstract The caller lacks privileges to perform the requested operation.
 103  */
 104 #define kOSKextReturnNotPrivileged                   libkern_kext_err(0x4)
 105
 106 /*!
 107  * @define   kOSKextReturnInvalidArgument
 108  * @abstract Invalid argument.
 109  */
 110 #define kOSKextReturnInvalidArgument                 libkern_kext_err(0x5)
 111
 112 /*!
 113  * @define   kOSKextReturnNotFound
 114  * @abstract Search item not found.
 115  */
 116 #define kOSKextReturnNotFound                        libkern_kext_err(0x6)
 117
 118 /*!
 119  * @define   kOSKextReturnBadData
 120  * @abstract Malformed data (not used for XML).
 121  */
 122 #define kOSKextReturnBadData                         libkern_kext_err(0x7)
 123
 124 /*!
 125  * @define   kOSKextReturnSerialization
 126  * @abstract Error converting or (un)serializing URL, string, or XML.
 127  */
 128 #define kOSKextReturnSerialization                   libkern_kext_err(0x8)
 129
 130 /*!
 131  * @define   kOSKextReturnUnsupported
 132  * @abstract Operation is no longer or not yet supported.
 133  */
 134 #define kOSKextReturnUnsupported                     libkern_kext_err(0x9)
 135
 136 /*!
 137  * @define   kOSKextReturnDisabled
 138  * @abstract Operation is currently disabled.
 139  */
 140 #define kOSKextReturnDisabled                        libkern_kext_err(0xa)
 141
 142 /*!
 143  * @define   kOSKextReturnNotAKext
 144  * @abstract Bundle is not a kernel extension.
 145  */
 146 #define kOSKextReturnNotAKext                        libkern_kext_err(0xb)
 147
 148 /*!
 149  * @define   kOSKextReturnValidation
 150  * @abstract Validation failures encountered; check diagnostics for details.
 151  */
 152 #define kOSKextReturnValidation                      libkern_kext_err(0xc)
 153
 154 /*!
 155  * @define   kOSKextReturnAuthentication
 156  * @abstract Authetication failures encountered; check diagnostics for details.
 157  */
 158 #define kOSKextReturnAuthentication                  libkern_kext_err(0xd)
 159
 160 /*!
 161  * @define   kOSKextReturnDependencies
 162  * @abstract Dependency resolution failures encountered; check diagnostics for details.
 163  */
 164 #define kOSKextReturnDependencies                    libkern_kext_err(0xe)
 165
 166 /*!
 167  * @define   kOSKextReturnArchNotFound
 168  * @abstract Kext does not contain code for the requested architecture.
 169  */
 170 #define kOSKextReturnArchNotFound                    libkern_kext_err(0xf)
 171
 172 /*!
 173  * @define   kOSKextReturnCache
 174  * @abstract An error occurred processing a system kext cache.
 175  */
 176 #define kOSKextReturnCache                           libkern_kext_err(0x10)
 177
 178 /*!
 179  * @define   kOSKextReturnDeferred
 180  * @abstract Operation has been posted asynchronously to user space (kernel only).
 181  */
 182 #define kOSKextReturnDeferred                        libkern_kext_err(0x11)
 183
 184 /*!
 185  * @define   kOSKextReturnBootLevel
 186  * @abstract Kext not loadable or operation not allowed at current boot level.
 187  */
 188 #define kOSKextReturnBootLevel                       libkern_kext_err(0x12)
 189
 190 /*!
 191  * @define   kOSKextReturnNotLoadable
 192  * @abstract Kext cannot be loaded; check diagnostics for details.
 193  */
 194 #define kOSKextReturnNotLoadable                     libkern_kext_err(0x13)
 195
 196 /*!
 197  * @define   kOSKextReturnLoadedVersionDiffers
 198  * @abstract A different version (or executable UUID, or executable by checksum)
 199  *           of the requested kext is already loaded.
 200  */
 201 #define kOSKextReturnLoadedVersionDiffers            libkern_kext_err(0x14)
 202
 203 /*!
 204  * @define   kOSKextReturnDependencyLoadError
 205  * @abstract A load error occurred on a dependency of the kext being loaded.
 206  */
 207 #define kOSKextReturnDependencyLoadError             libkern_kext_err(0x15)
 208
 209 /*!
 210  * @define   kOSKextReturnLinkError
 211  * @abstract A link failure occured with this kext or a dependency.
 212  */
 213 #define kOSKextReturnLinkError                       libkern_kext_err(0x16)
 214
 215 /*!
 216  * @define   kOSKextReturnStartStopError
 217  * @abstract The kext start or stop routine returned an error.
 218  */
 219 #define kOSKextReturnStartStopError                  libkern_kext_err(0x17)
 220
 221 /*!
 222  * @define   kOSKextReturnInUse
 223  * @abstract The kext is currently in use or has outstanding references,
 224  *           and cannot be unloaded.
 225  */
 226 #define kOSKextReturnInUse                           libkern_kext_err(0x18)
 227
 228 /*!
 229  * @define   kOSKextReturnTimeout
 230  * @abstract A kext request has timed out.
 231  */
 232 #define kOSKextReturnTimeout                         libkern_kext_err(0x19)
 233
 234 /*!
 235  * @define   kOSKextReturnStopping
 236  * @abstract The kext is in the process of stopping; requests cannot be made.
 237  */
 238 #define kOSKextReturnStopping                        libkern_kext_err(0x1a)
 239
 240 #if PRAGMA_MARK
 241 #pragma mark -
 242 /********************************************************************/
 243 #pragma mark Kext/OSBundle Property List Keys
 244 /********************************************************************/
 245 #endif
 246 /*!
 247  * @group Kext Property List Keys
 248  * These constants cover CFBundle properties defined for kernel extensions.
 249  * Because they are used in the kernel, if you want to use one with
 250  * CFBundle APIs you'll need to wrap it in a <code>CFSTR()</code> macro.
 251  */
 252
 253 #ifdef KERNEL
 254 /* Define C-string versions of the CFBundle keys for use in the kernel.
 255  */
 256 #define kCFBundleIdentifierKey                  "CFBundleIdentifier"
 257 #define kCFBundleVersionKey                     "CFBundleVersion"
 258 #define kCFBundleNameKey                        "CFBundleName"
 259 #define kCFBundleExecutableKey                  "CFBundleExecutable"
 260 #endif /* KERNEL */
 261
 262 /*!
 263  * @define   kOSBundleCompatibleVersionKey
 264  * @abstract A string giving the backwards-compatible version of a library kext
 265  *           in extended Mac OS 'vers' format (####.##.##s{1-255} where 's'
 266  *           is a build stage 'd', 'a', 'b', 'f' or 'fc').
 267  */
 268 #define kOSBundleCompatibleVersionKey           "OSBundleCompatibleVersion"
 269
 270 /*!
 271  * @define   kOSBundleEnableKextLoggingKey
 272  * @abstract Set to true to have the kernel kext logging spec applied
 273  *           to the kext.
 274  *           See <code>@link //apple_ref/c/econst/OSKextLogSpec
 275  *           OSKextLogSpec@/link</code>.
 276  */
 277 #define kOSBundleEnableKextLoggingKey           "OSBundleEnableKextLogging"
 278
 279 /*!
 280  * @define   kOSBundleIsInterfaceKey
 281  * @abstract A boolean value indicating whether the kext executable
 282  *           contains only symbol references.
 283  */
 284 #define kOSBundleIsInterfaceKey                 "OSBundleIsInterface"
 285
 286 /*!
 287  * @define   kOSBundleLibrariesKey
 288  * @abstract A dictionary listing link dependencies for this kext.
 289  *           Keys are bundle identifiers, values are version strings.
 290  */
 291 #define kOSBundleLibrariesKey                   "OSBundleLibraries"
 292
 293 /*!
 294  * @define   kOSBundleRequiredKey
 295  * @abstract A string indicating in which kinds of startup this kext
 296  *           may need to load during early startup (before
 297  *           <code>@link //apple_ref/doc/man/8/kextd kextcache(8)@/link</code>).
 298  * @discussion
 299  * The value is one of:
 300  * <ul>
 301  * <li>@link kOSBundleRequiredRoot "OSBundleRequiredRoot"@/link</li>
 302  * <li>@link kOSBundleRequiredLocalRoot "OSBundleRequiredLocalRoot"@/link</li>
 303  * <li>@link kOSBundleRequiredNetworkRoot "OSBundleRequiredNetworkRoot"@/link</li>
 304  * <li>@link kOSBundleRequiredSafeBoot "OSBundleRequiredSafeBoot"@/link</li>
 305  * <li>@link kOSBundleRequiredConsole "OSBundleRequiredConsole"@/link</li>
 306  * </ul>
 307  *
 308  * Use this property judiciously.
 309  * Every kext that declares a value other than "OSBundleRequiredSafeBoot"
 310  * increases startup time, as the booter must read it into memory,
 311  * or startup kext caches must include it.
 312  */
 313 #define kOSBundleRequiredKey                    "OSBundleRequired"
 314
 315 /*!
 316  * @define   kOSBundleAllowUserLoadKey
 317  * @abstract A boolean value indicating whether
 318  *           <code>@link //apple_ref/doc/man/8/kextd kextcache(8)@/link</code>
 319  *           will honor a non-root process's request to load a kext.
 320  * @discussion
 321  * See <code>@link //apple_ref/doc/compositePage/c/func/KextManagerLoadKextWithURL
 322  * KextManagerLoadKextWithURL@/link</code>
 323  * and <code>@link //apple_ref/doc/compositePage/c/func/KextManagerLoadKextWithIdentifier
 324  * KextManagerLoadKextWithIdentifier@/link</code>.
 325  */
 326 #define kOSBundleAllowUserLoadKey               "OSBundleAllowUserLoad"
 327
 328 /*!
 329  * @define   kOSKernelResourceKey
 330  * @abstract A boolean value indicating whether the kext represents a built-in
 331  *           component of the kernel.
 332  */
 333 #define kOSKernelResourceKey                    "OSKernelResource"
 334
 335 /*!
 336  * @define   kIOKitPersonalitiesKey
 337  * @abstract A dictionary of dictionaries used in matching for I/O Kit drivers.
 338  */
 339 #define kIOKitPersonalitiesKey                  "IOKitPersonalities"
 340
 341 /*
 342  * @define   kIOPersonalityPublisherKey
 343  * @abstract Used in personalities sent to the I/O Kit,
 344  *           contains the CFBundleIdentifier of the kext
 345  *           that the personality originated in.
 346  */
 347 #define kIOPersonalityPublisherKey              "IOPersonalityPublisher"
 348
 349
 350 #if PRAGMA_MARK
 351 /********************************************************************/
 352 #pragma mark Kext/OSBundle Property Deprecated Keys
 353 /********************************************************************/
 354 #endif
 355 /*
 356  * @define   kOSBundleDebugLevelKey
 357  * @abstract
 358  * Deprecated (used on some releases of Mac OS X prior to 10.6 Snow Leopard).
 359  * Value is an integer from 1-6, corresponding to the verbose levels
 360  * of kext tools on those releases.
 361  * On 10.6 Snow Leopard, use <code>@link OSKextEnableKextLogging
 362  * OSKextEnableKextLogging@/link</code>.
 363  */
 364 #define kOSBundleDebugLevelKey                  "OSBundleDebugLevel"
 365
 366 /*!
 367  * @define   kOSBundleSharedExecutableIdentifierKey
 368  * @abstract Deprecated (used on some releases of Mac OS X
 369  *           prior to 10.6 Snow Leopard).
 370  *           Value is the bundle identifier of the pseudokext
 371  *           that contains an executable shared by this kext.
 372  */
 373 #define kOSBundleSharedExecutableIdentifierKey  "OSBundleSharedExecutableIdentifier"
 374
 375
 376 #if PRAGMA_MARK
 377 /********************************************************************/
 378 #pragma mark Kext/OSBundle Property List Values
 379 /********************************************************************/
 380 #endif
 381
 382 /*!
 383  * @group Kext Property List Values
 384  * These constants encompass established values
 385  * for kernel extension bundle properties.
 386  */
 387
 388 /*!
 389 * @define   kOSKextKernelIdentifier
 390 * @abstract
 391 * This is the CFBundleIdentifier user for the kernel itself.
 392 */
 393 #define kOSKextKernelIdentifier                 "__kernel__"
 394
 395 /*!
 396 * @define   kOSBundleRequiredRoot
 397 * @abstract
 398 * This <code>@link kOSBundleRequiredKey OSBundleRequired@/link</code>
 399 * value indicates that the kext may be needed to mount the root filesystem
 400 * whether starting from a local or a network volume.
 401 */
 402 #define kOSBundleRequiredRoot                   "Root"
 403
 404 /*!
 405 * @define   kOSBundleRequiredLocalRoot
 406 * @abstract
 407 * This <code>@link kOSBundleRequiredKey OSBundleRequired@/link</code>
 408 * value indicates that the kext may be needed to mount the root filesystem
 409 * when starting from a local disk.
 410 */
 411 #define kOSBundleRequiredLocalRoot              "Local-Root"
 412
 413 /*!
 414 * @define   kOSBundleRequiredNetworkRoot
 415 * @abstract
 416 * This <code>@link kOSBundleRequiredKey OSBundleRequired@/link</code>
 417 * value indicates that the kext may be needed to mount the root filesystem
 418 * when starting over a network connection.
 419 */
 420 #define kOSBundleRequiredNetworkRoot            "Network-Root"
 421
 422 /*!
 423 * @define   kOSBundleRequiredSafeBoot
 424 * @abstract
 425 * This <code>@link kOSBundleRequiredKey OSBundleRequired@/link</code>
 426 * value indicates that the kext can be loaded during a safe startup.
 427 * This value does not normally cause the kext to be read by the booter
 428 * or included in startup kext caches.
 429 */
 430 #define kOSBundleRequiredSafeBoot               "Safe Boot"
 431
 432 /*!
 433 * @define   kOSBundleRequiredConsole
 434 * @abstract
 435 * This <code>@link kOSBundleRequiredKey OSBundleRequired@/link</code>
 436 * value indicates that the kext may be needed for console access
 437 * (specifically in a single-user startup when
 438 * <code>@link //apple_ref/doc/man/8/kextd kextd(8)@/link</code>.
 439 * does not run)
 440 * and should be loaded during early startup.
 441 */
 442 #define kOSBundleRequiredConsole                "Console"
 443
 444
 445 #if PRAGMA_MARK
 446 #pragma mark -
 447 /********************************************************************/
 448 #pragma mark Kext Information
 449 /********************************************************************/
 450 #endif
 451 /*!
 452  * @group Kext Information
 453  * Types, constants, and macros providing a kext with information
 454  * about itself.
 455  */
 456
 457 /*!
 458  * @typedef OSKextLoadTag
 459  *
 460  * @abstract
 461  * A unique identifier assigned to a loaded instanace of a kext.
 462  *
 463  * @discussion
 464  * If a kext is unloaded and later reloaded, the new instance
 465  * has a different load tag.
 466  *
 467  * A kext can get its own load tag in the <code>kmod_info_t</code>
 468  * structure passed into its module start routine, as the
 469  * <code>id</code> field (cast to this type).
 470  * You can use the load tag with the functions
 471  * <code>@link OSKextRetainKextWithLoadTag
 472  * OSKextRetainKextWithLoadTag@/link</code> and
 473  * <code>@link OSKextReleaseKextWithLoadTag
 474  * OSKextReleaseKextWithLoadTag@/link</code>.
 475  */
 476 typedef uint32_t  OSKextLoadTag;
 477
 478 /*!
 479  * @define kOSKextInvalidLoadTag
 480  *
 481  * @abstract
 482  * A load tag value that will never be used for a loaded kext;
 483  * indicates kext not found.
 484  */
 485 #define  kOSKextInvalidLoadTag  ((OSKextLoadTag)(-1))
 486
 487
 488 #ifdef KERNEL
 489
 490 /* Make these visible to kexts only and *not* the kernel.
 491  */
 492 #if !XNU_KERNEL_PRIVATE
 493
 494 /*!
 495  * @function OSKextGetCurrentLoadTag
 496  *
 497  * @abstract
 498  * Returns the run-time load tag for the calling kext as an
 499  * <code>@link OSKextLoadTag OSKextLoadTag@/link</code>.
 500  *
 501  * @result
 502  * The run-time load tag for the calling kext as an
 503  * <code>@link OSKextLoadTag@/link</code>.
 504  *
 505  * @discussion
 506  * The load tag identifies this loaded instance of the kext to the kernel
 507  * and to kernel functions that operate on kexts.
 508  */
 509 OSKextLoadTag OSKextGetCurrentLoadTag(void);
 510
 511 /*!
 512  * @function OSKextGetCurrentIdentifier
 513  *
 514  * @abstract
 515  * Returns the CFBundleIdentifier for the calling kext as a C string.
 516  *
 517  * @result
 518  * The CFBundleIdentifier for the calling kext as a C string.
 519  */
 520 const char * OSKextGetCurrentIdentifier(void);
 521
 522 /*!
 523  * @function OSKextGetCurrentVersionString
 524  *
 525  * @abstract
 526  * Returns the CFBundleVersion for the calling kext as a C string.
 527  *
 528  * @result
 529  * The CFBundleVersion for the calling kext as a C string.
 530  */
 531 const char * OSKextGetCurrentVersionString(void);
 532
 533 #endif /* !XNU_KERNEL_PRIVATE */
 534
 535 #if PRAGMA_MARK
 536 #pragma mark -
 537 /********************************************************************/
 538 #pragma mark Kext Loading C Functions
 539 /********************************************************************/
 540 #endif
 541 /*!
 542  * @group Kext Loading C Functions
 543  * Functions for loading and tracking kexts in the kernel.
 544  */
 545
 546 /*!
 547  * @function OSKextLoadKextWithIdentifier
 548  *
 549  * @abstract
 550  * Request that a kext be loaded.
 551  *
 552  * @param  kextIdentifier  The bundle identifier of the kext to be loaded.
 553  *
 554  * @result
 555  * <code>@link //apple_ref/c/macro/kOSReturnSuccess kOSReturnSuccess@/link</code>
 556  * if the kext was loaded (or was already loaded).
 557  * <code>@link //apple_ref/c/macro/kOSKextReturnDeferred kOSKextReturnDeferred@/link</code>
 558  * if the kext was not found and a request
 559  * was queued to <code>@link //apple_ref/doc/man/8/kextd kextd(8)@/link</code>.
 560  * Other return values indicate a failure to load the kext.
 561  *
 562  * @discussion
 563  * If a kext is already in the kernel but not loaded, it is loaded immediately.
 564  * If it isn't found, an asynchronous load request is
 565  * made to <code>@link //apple_ref/doc/man/8/kextd kextd(8)@/link</code>
 566  * and  <code>@link //apple_ref/c/macro/kOSKextReturnDeferred kOSKextReturnDeferred@/link</code> is returned.
 567  * There is no general notification or callback mechanism for load requests.
 568  */
 569 OSReturn OSKextLoadKextWithIdentifier(const char * kextIdentifier);
 570
 571
 572 /*!
 573  * @function OSKextRetainKextWithLoadTag
 574  *
 575  * @abstract
 576  * Retain a loaded kext based on its load tag,
 577  * and enable autounload for that kext.
 578  *
 579  * @param  loadTag   The load tag of the kext to be retained.
 580  *                   See <code>@link OSKextGetCurrentLoadTag@/link</code>.
 581  *
 582  * @result
 583  * <code>@link //apple_ref/c/macro/kOSReturnSuccess kOSReturnSuccess@/link</code>
 584  * if the kext was retained.
 585  * <code>@link //apple_ref/c/macro/kOSKextReturnNotFound kOSKextReturnNotFound@/link</code>
 586  * if the kext was not found.
 587  * <code>@link //apple_ref/c/macro/kOSKextReturnInvalidArgument
 588  * kOSKextReturnInvalidArgument@/link</code>
 589  * if <code>loadTag</code> is
 590  * <code>@link kOSKextInvalidLoadTag kOSKextInvalidLoadTag@/link</code>.
 591  *
 592  * @discussion
 593  * Retaining a kext prevents it from being unloaded,
 594  * either explicitly or automatically, and enables autounload for the kext.
 595  * When autounload is enabled, then shortly after the kext's last reference
 596  * is dropped, it will be unloaded if there are no outstanding references to it
 597  * and there are no instances of its Libkern C++ subclasses (if any).
 598  *
 599  * Kexts that define subclasses of
 600  * <code>@link //apple_ref/doc/class/IOService IOService@/link</code>
 601  * have autounload enabled automatically.
 602  * Other kexts can use the reference count to manage automatic unload
 603  * without having to define and create Libkern C++ objects.
 604  * For example, a filesystem kext can retain itself whenever a new mount
 605  * is created, and release itself when a mount is removed.
 606  * When the last mount is removed, the kext will be unloaded after a brief delay.
 607  *
 608  * A kext can get its own load tag using the
 609  * <code>@link OSKextGetCurrentLoadTag@/link</code>.
 610  *
 611  * Kexts should not retain and release other kexts; linkage references
 612  * are accounted for internally.
 613  */
 614 OSReturn OSKextRetainKextWithLoadTag(OSKextLoadTag loadTag);
 615
 616
 617 /*!
 618  * @function OSKextReleaseKextWithLoadTag
 619  *
 620  * @abstract
 621  * Release a loaded kext based on its load tag.
 622  *
 623  * @param  loadTag   The load tag of the kext to be released.
 624  *                   See <code>@link OSKextGetCurrentLoadTag@/link</code>.
 625  *
 626  * @result
 627  * <code>@link //apple_ref/c/macro/kOSReturnSuccess kOSReturnSuccess@/link</code>
 628  * if the kext was released.
 629  * <code>@link //apple_ref/c/macro/kOSKextReturnNotFound
 630  * kOSKextReturnNotFound@/link</code>
 631  * if the kext was not found.
 632  * <code>@link //apple_ref/c/macro/kOSKextReturnInvalidArgument
 633  * kOSKextReturnInvalidArgument@/link</code>
 634  * if <code>loadTag</code> is
 635  * <code>@link kOSKextInvalidLoadTag kOSKextInvalidLoadTag@/link</code>.
 636  *
 637  * @discussion
 638  * The kext should have been retained previously via
 639  * <code>@link OSKextRetainKextWithLoadTag@/link</code>.
 640  *
 641  * This function schedules an autounload scan for all kexts.
 642  * When that scan occurs, if a kext has autounload enabled,
 643  * it will be unloaded if there are no outstanding references to it
 644  * and there are no instances of its Libkern C++ classes (if any).
 645  *
 646  * Kexts that define subclasses of
 647  * <code>@link //apple_ref/doc/class/IOService IOService@/link</code>
 648  * have autounload enabled automatically.
 649  * Other kexts can use the reference count to manage automatic unload
 650  * without having to define and create Libkern C++ objects.
 651  * For example, a filesystem kext can be retained whenever a new mount
 652  * is created, and released when a mount is removed.
 653  * When the last mount is removed, the kext will be unloaded after a brief delay.
 654  *
 655  * While the autounload scan takes place after a delay of at least a minute,
 656  * a kext that manages its own reference counts for autounload should
 657  * be prepared to have its module stop function called even while the function
 658  * calling this function is still running.
 659  *
 660  * A kext can get its own load tag using the
 661  * <code>@link OSKextGetCurrentLoadTag@/link</code>.
 662  *
 663  * Kexts should not retain and release other kexts; linkage references
 664  * are accounted for internally.
 665  */
 666 OSReturn OSKextReleaseKextWithLoadTag(OSKextLoadTag loadTag);
 667
 668 #if PRAGMA_MARK
 669 /********************************************************************/
 670 #pragma mark -
 671 #pragma mark Kext Requests
 672 /********************************************************************/
 673 #endif
 674 /*!
 675  * @group Kext Requests to User Space
 676  * Functions for making requests to kextd in user space.
 677  */
 678
 679 /*!
 680  * @typedef OSKextRequestTag
 681  *
 682  * @abstract
 683  * Identifies a kext request made to user space.
 684  */
 685 typedef uint32_t OSKextRequestTag;
 686
 687 /*!
 688  * @define kOSKextRequestTagInvalid
 689  *
 690  * @abstract
 691  * A request tag value that will never be used for a kext request;
 692  * indicates failure to create/queue the request.
 693  */
 694 #define kOSKextRequestTagInvalid  ((OSKextRequestTag)-1)
 695
 696 /*!
 697  * @typedef OSKextRequestResourceCallback
 698  *
 699  * @abstract
 700  * Invoked to provide results for a kext resource request.
 701  *
 702  * @param  requestTag          The tag of the request that the callback pertains to.
 703  * @param  result              The result of the request:
 704  *                             <code>@link kOSReturnSuccess
 705  *                             kOSReturnSuccess@/link</code>
 706  *                             if the request was fulfilled;
 707  *                             <code>@link kOSKextReturnTimeout
 708  *                             kOSKextReturnTimeout@/link</code>
 709  *                             if the request has timed out;
 710  *                             <code>@link kOSKextReturnStopping
 711  *                             kOSKextReturnStopping@/link</code>
 712  *                             if the kext containing the callback
 713  *                             address for the kext is being unloaded;
 714  *                             or other values on error.
 715  * @param  resourceData        A pointer to the requested resource data.
 716  *                             Owned by the system; the kext should make a copy
 717  *                             if it needs to keep the data past the callback.
 718  * @param  resourceDataLength  The length of <code>resourceData</code>.
 719  * @param  context             The context pointer originally passed to
 720  *                             <code>@link OSKextRequestResource
 721  *                             OSKextRequestResource@/link</code>.
 722  */
 723 typedef void (* OSKextRequestResourceCallback)(
 724     OSKextRequestTag                requestTag,
 725     OSReturn                        result,
 726     const void                    * resourceData,
 727     uint32_t                        resourceDataLength,
 728     void                          * context);
 729
 730 /*!
 731  * @function OSKextRequestResource
 732  *
 733  * @abstract
 734  * Requests data from a nonlocalized resource file in a kext bundle on disk.
 735  *
 736  * @param  kextIdentifier  The CFBundleIdentifier of the kext
 737  *                         from which to read the file.
 738  * @param  resourceName    The name of the resource file to read.
 739  * @param  callback        A pointer to a callback function; the address
 740  *                         must be within a currently-loaded kext.
 741  * @param  context         A pointer to arbitrary run-time data
 742  *                         that will be passed to the callback
 743  *                         when it is invoked. May be <code>NULL</code>.
 744  * @param  requestTagOut   If non-<code>NULL</code>,
 745  *                         filled on success with a tag identifying the
 746  *                         pending request
 747  *                         (or on failure with <code>@link kOSKextRequestTagInvalid
 748  *                         kOSKextRequestTagInvalid@/link</code>;
 749  *                         can be used with
 750  *                         <code>@link OSKextCancelRequest
 751  *                         OSKextCancelRequest@/link</code>.
 752  *
 753  * @result
 754  * <code>@link kOSReturnSuccess kOSReturnSuccess@/link</code>
 755  * if the request is successfully queued.
 756  * <code>@link kOSKextReturnInvalidArgument kOSKextReturnInvalidArgument@/link</code>
 757  * if <code>kextIdentifier</code> or <code>resourceName</code> or if
 758  * <code>callback</code> is not an address within a loaded kext executable.
 759  * <code>@link kOSKextReturnStopping kOSKextReturnStopping@/link</code>
 760  * if an unload attempt is being made
 761  * on the kext containing <code>callback</code>.
 762  * Other <code>OSKextReturn...</code> errors are possible.
 763  *
 764  * @discussion
 765  * This function queues an asynchronous request to the user-space kext daemon
 766  * <code>@link //apple_ref/doc/man/8/kextd kextd(8)@/link</code>;
 767  * requests for resources early in system startup
 768  * will not be fulfilled until that daemon starts.
 769  * Requests made by a kext while that kext is loading
 770  * (specifically in the kext's module start routine)
 771  * will not be fulfilled until after the start routine returns and
 772  * the kext is completely loaded.
 773  * Kexts requesting resources should be sure to perform appropriate locking
 774  * in the callback function.
 775  *
 776  * Kext resources are stored in the kext's on-disk bundle under the
 777  * Resources subdirectory.
 778  * See {@linkdoc //apple_ref/doc/uid/10000123i Bundle Programming Guide}
 779  * for an overview of bundle structure.
 780  * The localization context of the kext daemon
 781  * (namely that of the superuser)
 782  * will be used in retrieving resources;
 783  * kext resources intended for use in the kernel
 784  * should generally not be localized.
 785  *
 786  * <code>callback</code> is guaranteed to be invoked except when:
 787  * <ul>
 788  * <li>@link OSKextCancelRequest <code>OSKextCancelRequest</code>@/link
 789  *     is used to cancel the request.
 790  *     In this case the kext gets the <code>context</code> pointer
 791  *     and can clean it up.</li>
 792  * <li>The request is made during a kext's module start routine
 793  *     and the start routine returns an error.
 794  *     In this case, callbacks cannot be safely invoked, so
 795  *     the kext should clean up all request contexts
 796  *     when returning the error from the start routine.</li>
 797  * </ul>
 798  *
 799  * Kexts with pending requests are not subject to autounload,
 800  * but requests are subject to timeout after a few minutes.
 801  * If that amount of time passes with no response from user space,
 802  * <code>callback</code> is invoked with a result of.
 803  * <code>@link kOSKextReturnTimeout kOSKextReturnTimeout@/link</code>.
 804  *
 805  * Kexts that are explicitly unloaded have all pending request callbacks
 806  * invoked with a result of
 807  * <code>@link kOSKextReturnStopping kOSKextReturnStopping@/link</code>.
 808  * The kext must handle these callbacks,
 809  * even if its stop routine will prevent unloading.
 810  * If the kext does prevent unloading, it can reissue resource requests
 811  * outside of the stop function.
 812  */
 813 OSReturn OSKextRequestResource(
 814     const char                    * kextIdentifier,
 815     const char                    * resourceName,
 816     OSKextRequestResourceCallback   callback,
 817     void                          * context,
 818     OSKextRequestTag              * requestTagOut);
 819
 820 /*!
 821  * @function OSKextCancelRequest
 822  *
 823  * @abstract
 824  * Cancels a pending user-space kext request without invoking the callback.
 825  *
 826  * @param  requestTag  A tag identifying a pending request.
 827  * @param  contextOut  If non-<code>NULL</code>, filled with the context pointer
 828  *                     originally passed with the request.
 829  *
 830  * @result
 831  * <code>@link kOSReturnSuccess kOSReturnSuccess@/link</code>
 832  * if the request is successfully canceled.
 833  * <code>@link kOSKextReturnNotFound kOSKextReturnNotFound@/link</code>
 834  * if <code>requestTag</code> does not identify any pending request.
 835  * Other <code>OSKextReturn...</code> errors are possible.
 836  *
 837  * @discussion
 838  * This function cancels a pending request if it exists,
 839  * so that its callback will not be invoked.
 840  * It returns in <code>contextOut</code>
 841  * the context pointer used to create the request
 842  * so that any resources allocated for the request can be cleaned up.
 843  *
 844  * Kexts do not need to cancel outstanding requests
 845  * in their module stop functions;
 846  * when a kext is unloaded, all pending request callbacks
 847  * are invoked with a result of
 848  * <code>@link kOSKextReturnTimeout kOSKextReturnTimeout@/link</code>
 849  * before the stop function is called.
 850  */
 851 OSReturn OSKextCancelRequest(
 852     OSKextRequestTag    requestTag,
 853     void             ** contextOut);
 854
 855
 856 #if PRAGMA_MARK
 857 #pragma mark -
 858 /********************************************************************/
 859 #pragma mark Weak linking
 860 /********************************************************************/
 861 #endif
 862 /*!
 863  * @group Weak Linking
 864  * Support for weak references to symbols in kexts.
 865  */
 866
 867 /*!
 868  * @var gOSKextUnresolved
 869  *
 870  * @abstract
 871  * The value to which a kext's unresolved, weakly-referenced symbols are bound.
 872  *
 873  * @discussion
 874  * A kext must test a weak symbol before using it.  A weak symbol
 875  * is only safe to use if it is not equal to <code>gOSKextUnresolved</code>.
 876  *
 877  * Example for a weak symbol named <code>foo</code>:
 878  * <pre>
 879  * @textblock
 880  *      if (&foo != gOSKextUnresolved) {
 881  *          foo();
 882  *      } else {
 883  *          printf("foo() is not supported\n");
 884  *      }
 885  * @/textblock
 886  * </pre>
 887  */
 888 extern const void * gOSKextUnresolved;
 889
 890 /*!
 891  * @define OSKextSymbolIsResolved
 892  *
 893  * @abstract
 894  * Checks whether a weakly-referenced symbol has been resolved.
 895  *
 896  * @param weak_sym   The weak symbol to be tested for resolution.
 897  *
 898  * @result
 899  * <code>TRUE</code> if weak_sym is resolved, or <code>FALSE</code>
 900  * if weak_sym is unresolved.
 901  *
 902  * @discussion
 903  * This is a convenience macro for testing if weak symbols are resolved.
 904  *
 905  * Example for a weak symbol named <code>foo</code>:
 906  * <pre>
 907  * @textblock
 908  *      if (OSKextSymbolIsResolved(foo)) {
 909  *          foo();
 910  *      } else {
 911  *          printf("foo() is not resolved\n");
 912  *      }
 913  * @/textblock
 914  * </pre>
 915  */
 916 #define OSKextSymbolIsResolved(weak_sym)        \
 917     (&(weak_sym) != gOSKextUnresolved)
 918
 919 #endif /* KERNEL */
 920
 921 __END_DECLS
 922
 923 #endif /* _LIBKERN_OSKEXTLIB_H */