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1/*␊
2 * Copyright (c) 1999-2003 Apple Computer, Inc. All rights reserved.␊
3 *␊
4 * @APPLE_LICENSE_HEADER_START@␊
5 * ␊
6 * Portions Copyright (c) 1999-2003 Apple Computer, Inc. All Rights␊
7 * Reserved. This file contains Original Code and/or Modifications of␊
8 * Original Code as defined in and that are subject to the Apple Public␊
9 * Source License Version 2.0 (the "License"). You may not use this file␊
10 * except in compliance with the License. Please obtain a copy of the␊
11 * License at http://www.apple.com/publicsource and read it before using␊
12 * this file.␊
13 * ␊
14 * The Original Code and all software distributed under the License are␊
15 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER␊
16 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,␊
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,␊
18 * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT. Please see the␊
19 * License for the specific language governing rights and limitations␊
20 * under the License.␊
21 * ␊
22 * @APPLE_LICENSE_HEADER_END@␊
23 */␊
24/* ␊
25 * Mach Operating System␊
26 * Copyright (c) 1990 Carnegie-Mellon University␊
27 * Copyright (c) 1989 Carnegie-Mellon University␊
28 * All rights reserved. The CMU software License Agreement specifies␊
29 * the terms and conditions for use and redistribution.␊
30 */␊
31␊
32/*␊
33 * INTEL CORPORATION PROPRIETARY INFORMATION␊
34 *␊
35 * This software is supplied under the terms of a license agreement or ␊
36 * nondisclosure agreement with Intel Corporation and may not be copied ␊
37 * nor disclosed except in accordance with the terms of that agreement.␊
38 *␊
39 * Copyright 1988, 1989 by Intel Corporation␊
40 */␊
41␊
42/*␊
43 * Copyright 1993 NeXT Computer, Inc.␊
44 * All rights reserved.␊
45 */␊
46 ␊
47/*␊
48 * Completely reworked by Sam Streeper (sam_s@NeXT.com)␊
49 * Reworked again by Curtis Galloway (galloway@NeXT.com)␊
50 */␊
51␊
52␊
53#include "boot.h"␊
54#include "bootstruct.h"␊
55#include "fake_efi.h"␊
56#include "sl.h"␊
57#include "libsa.h"␊
58#include "ramdisk.h"␊
59#include "gui.h"␊
60#include "platform.h"␊
61␊
62long gBootMode; /* defaults to 0 == kBootModeNormal */␊
63bool gOverrideKernel;␊
64static char gBootKernelCacheFile[512];␊
65static char gCacheNameAdler[64 + 256];␊
66char *gPlatformName = gCacheNameAdler;␊
67char gRootDevice[512];␊
68char gMKextName[512];␊
69char gMacOSVersion[8];␊
70bool gEnableCDROMRescan;␊
71bool gScanSingleDrive;␊
72␊
73int bvCount = 0;␊
74//int␉␉menucount = 0;␊
75int gDeviceCount = 0; ␊
76␊
77BVRef bvr;␊
78BVRef menuBVR;␊
79BVRef bvChain;␊
80bool useGUI;␊
81␊
82//static void selectBiosDevice(void);␊
83static unsigned long Adler32(unsigned char *buffer, long length);␊
84␊
85␊
86static bool gUnloadPXEOnExit = false;␊
87␊
88/*␊
89 * How long to wait (in seconds) to load the␊
90 * kernel after displaying the "boot:" prompt.␊
91 */␊
92#define kBootErrorTimeout 5␊
93␊
94/*␊
95 * Default path to kernel cache file␊
96 */␊
97#define kDefaultCachePath "/System/Library/Caches/com.apple.kernelcaches/kernelcache"␊
98␊
99//==========================================================================␊
100// Zero the BSS.␊
101␊
102static void zeroBSS(void)␊
103{␊
104␉extern char _DATA__bss__begin, _DATA__bss__end;␊
105␉extern char _DATA__common__begin, _DATA__common__end;␊
106␊
107␉bzero(&_DATA__bss__begin, (&_DATA__bss__end - &_DATA__bss__begin));␊
108␉bzero(&_DATA__common__begin, (&_DATA__common__end - &_DATA__common__begin));␊
109}␊
110␊
111//==========================================================================␊
112// Malloc error function␊
113␊
114static void malloc_error(char *addr, size_t size, const char *file, int line)␊
115{␊
116␉stop("\nMemory allocation error! Addr=0x%x, Size=0x%x, File=%s, Line=%d\n", (unsigned)addr, (unsigned)size, file, line);␊
117}␊
118␊
119//==========================================================================␊
120//Initializes the runtime. Right now this means zeroing the BSS and initializing malloc.␊
121//␊
122void initialize_runtime(void)␊
123{␊
124␉zeroBSS();␊
125␉malloc_init(0, 0, 0, malloc_error);␊
126}␊
127␊
128//==========================================================================␊
129// execKernel - Load the kernel image (mach-o) and jump to its entry point.␊
130␊
131static int ExecKernel(void *binary)␊
132{␊
133 entry_t kernelEntry;␊
134 int ret;␊
135␊
136 bootArgs->kaddr = bootArgs->ksize = 0;␊
137␊
138 ret = DecodeKernel(binary,␊
139 &kernelEntry,␊
140 (char **) &bootArgs->kaddr,␊
141 (int *)&bootArgs->ksize );␊
142␊
143 if ( ret != 0 )␊
144 return ret;␊
145␊
146 // Reserve space for boot args␊
147 reserveKernBootStruct();␊
148␊
149 // Load boot drivers from the specifed root path.␊
150␊
151 if (!gHaveKernelCache) {␊
152 LoadDrivers("/");␊
153 }␊
154␊
155 clearActivityIndicator();␊
156␊
157 if (gErrors) {␊
158 printf("Errors encountered while starting up the computer.\n");␊
159 printf("Pausing %d seconds...\n", kBootErrorTimeout);␊
160 sleep(kBootErrorTimeout);␊
161 }␊
162␊
163 setupFakeEfi();␊
164␊
165 md0Ramdisk();␊
166␊
167 verbose("Starting Darwin %s\n",( archCpuType == CPU_TYPE_I386 ) ? "x86" : "x86_64");␊
168␊
169 // Cleanup the PXE base code.␊
170␊
171 if ( (gBootFileType == kNetworkDeviceType) && gUnloadPXEOnExit ) {␊
172␉␉if ( (ret = nbpUnloadBaseCode()) != nbpStatusSuccess )␊
173 {␊
174 ␉printf("nbpUnloadBaseCode error %d\n", (int) ret);␊
175 sleep(2);␊
176 }␊
177 }␊
178␊
179 bool dummyVal;␊
180␉if (getBoolForKey(kWaitForKeypressKey, &dummyVal, &bootInfo->bootConfig) && dummyVal) {␊
181␉␉printf("Press any key to continue...");␊
182␉␉getc();␊
183␉}␊
184␊
185␉usb_loop();␊
186␊
187 // If we were in text mode, switch to graphics mode.␊
188 // This will draw the boot graphics unless we are in␊
189 // verbose mode.␊
190␊
191 if(gVerboseMode)␊
192 setVideoMode( GRAPHICS_MODE, 0 );␊
193 else␊
194 drawBootGraphics();␊
195␉␊
196␉setupBooterLog();␊
197␉␊
198 finalizeBootStruct();␊
199 ␊
200 // Jump to kernel's entry point. There's no going back now.␊
201␊
202 startprog( kernelEntry, bootArgs );␊
203␊
204 // Not reached␊
205␊
206 return 0;␊
207}␊
208␊
209//==========================================================================␊
210// This is the entrypoint from real-mode which functions exactly as it did␊
211// before. Multiboot does its own runtime initialization, does some of its␊
212// own things, and then calls common_boot.␊
213void boot(int biosdev)␊
214{␊
215␉initialize_runtime();␊
216␉// Enable A20 gate before accessing memory above 1Mb.␊
217␉enableA20();␊
218␉common_boot(biosdev);␊
219}␊
220␊
221//==========================================================================␊
222// The 'main' function for the booter. Called by boot0 when booting␊
223// from a block device, or by the network booter.␊
224//␊
225// arguments:␊
226// biosdev - Value passed from boot1/NBP to specify the device␊
227// that the booter was loaded from.␊
228//␊
229// If biosdev is kBIOSDevNetwork, then this function will return if␊
230// booting was unsuccessful. This allows the PXE firmware to try the␊
231// next boot device on its list.␊
232void common_boot(int biosdev)␊
233{␊
234 int status;␊
235 char *bootFile;␊
236 unsigned long adler32;␊
237 bool quiet;␊
238 bool firstRun = true;␊
239 bool instantMenu;␊
240 bool rescanPrompt;␊
241 unsigned int allowBVFlags = kBVFlagSystemVolume|kBVFlagForeignBoot;␊
242 unsigned int denyBVFlags = kBVFlagEFISystem;␊
243␊
244 // Set reminder to unload the PXE base code. Neglect to unload␊
245 // the base code will result in a hang or kernel panic.␊
246 gUnloadPXEOnExit = true;␊
247␊
248 // Record the device that the booter was loaded from.␊
249 gBIOSDev = biosdev & kBIOSDevMask;␊
250␊
251 // Initialize boot info structure.␊
252 initKernBootStruct();␊
253␊
254␉initBooterLog();␊
255␊
256 // Setup VGA text mode.␊
257 // Not sure if it is safe to call setVideoMode() before the␊
258 // config table has been loaded. Call video_mode() instead.␊
259#if DEBUG␊
260 printf("before video_mode\n");␊
261#endif␊
262 video_mode( 2 ); // 80x25 mono text mode.␊
263#if DEBUG␊
264 printf("after video_mode\n");␊
265#endif␊
266␊
267 // Scan and record the system's hardware information.␊
268 scan_platform();␊
269␊
270 // First get info for boot volume.␊
271 scanBootVolumes(gBIOSDev, 0);␊
272 bvChain = getBVChainForBIOSDev(gBIOSDev);␊
273 setBootGlobals(bvChain);␊
274 ␊
275 // Load boot.plist config file␊
276 status = loadSystemConfig(&bootInfo->bootConfig);␊
277␊
278 if (getBoolForKey(kQuietBootKey, &quiet, &bootInfo->bootConfig) && quiet) {␊
279 gBootMode |= kBootModeQuiet;␊
280 }␊
281␊
282 // Override firstRun to get to the boot menu instantly by setting "Instant Menu"=y in system config␊
283 if (getBoolForKey(kInsantMenuKey, &instantMenu, &bootInfo->bootConfig) && instantMenu) {␊
284 firstRun = false;␊
285 }␊
286␊
287 // Loading preboot ramdisk if exists.␊
288 loadPrebootRAMDisk();␊
289␊
290 // Disable rescan option by default␊
291 gEnableCDROMRescan = false;␊
292␊
293 // Enable it with Rescan=y in system config␊
294 if (getBoolForKey(kRescanKey, &gEnableCDROMRescan, &bootInfo->bootConfig) && gEnableCDROMRescan) {␊
295 gEnableCDROMRescan = true;␊
296 }␊
297␊
298 // Ask the user for Rescan option by setting "Rescan Prompt"=y in system config.␊
299 rescanPrompt = false;␊
300 if (getBoolForKey(kRescanPromptKey, &rescanPrompt , &bootInfo->bootConfig) && rescanPrompt && biosDevIsCDROM(gBIOSDev)) {␊
301 gEnableCDROMRescan = promptForRescanOption();␊
302 }␊
303␊
304 // Enable touching a single BIOS device only if "Scan Single Drive"=y is set in system config.␊
305 if (getBoolForKey(kScanSingleDriveKey, &gScanSingleDrive, &bootInfo->bootConfig) && gScanSingleDrive) {␊
306 gScanSingleDrive = true;␊
307 }␊
308␊
309 // Create a list of partitions on device(s).␊
310 if (gScanSingleDrive) {␊
311 scanBootVolumes(gBIOSDev, &bvCount);␊
312 } else {␊
313 scanDisks(gBIOSDev, &bvCount);␊
314 }␊
315␊
316 // Create a separated bvr chain using the specified filters.␊
317 bvChain = newFilteredBVChain(0x80, 0xFF, allowBVFlags, denyBVFlags, &gDeviceCount);␊
318␊
319 gBootVolume = selectBootVolume(bvChain);␊
320␊
321#if DEBUG␊
322 printf(" Default: %d, ->biosdev: %d, ->part_no: %d ->flags: %d\n", gBootVolume, gBootVolume->biosdev, gBootVolume->part_no, gBootVolume->flags);␊
323 printf(" bt(0,0): %d, ->biosdev: %d, ->part_no: %d ->flags: %d\n", gBIOSBootVolume, gBIOSBootVolume->biosdev, gBIOSBootVolume->part_no, gBIOSBootVolume->flags);␊
324 getc();␊
325#endif␊
326␊
327␉useGUI = true;␊
328␉// Override useGUI default␊
329␉getBoolForKey(kGUIKey, &useGUI, &bootInfo->bootConfig);␊
330␉if (useGUI && initGUI())␊
331␉{␊
332␉␉// initGUI() returned with an error, disabling GUI.␊
333␉␉useGUI = false;␊
334␉}␊
335␊
336 setBootGlobals(bvChain);␊
337␊
338 // Parse args, load and start kernel.␊
339 while (1) {␊
340 const char *val;␊
341 int len;␊
342 int trycache;␊
343 long flags, cachetime, kerneltime, exttime, sleeptime, time;␊
344 int ret = -1;␊
345 void *binary = (void *)kLoadAddr;␊
346 bool tryresume;␊
347 bool tryresumedefault;␊
348 bool forceresume;␊
349␊
350 config_file_t systemVersion;␉␉// system.plist of booting partition␊
351␊
352 // additional variable for testing alternate kernel image locations on boot helper partitions.␊
353 char bootFileSpec[512];␊
354␉␉␊
355 // Initialize globals.␊
356␊
357 sysConfigValid = false;␊
358 gErrors = false;␊
359␊
360 status = getBootOptions(firstRun);␊
361 firstRun = false;␊
362 if (status == -1) continue;␊
363␉␉ ␊
364 status = processBootOptions();␊
365 // Status==1 means to chainboot␊
366 if ( status == 1 ) break;␊
367 // Status==-1 means that the config file couldn't be loaded or that gBootVolume is NULL␊
368 if ( status == -1 )␊
369 {␊
370 // gBootVolume == NULL usually means the user hit escape.␊
371 if(gBootVolume == NULL)␊
372 {␊
373 freeFilteredBVChain(bvChain);␊
374␊
375 if (gEnableCDROMRescan)␊
376 rescanBIOSDevice(gBIOSDev);␊
377 ␊
378 bvChain = newFilteredBVChain(0x80, 0xFF, allowBVFlags, denyBVFlags, &gDeviceCount);␊
379 setBootGlobals(bvChain);␊
380 setupDeviceList(&bootInfo->themeConfig);␊
381 }␊
382 continue;␊
383 }␊
384␉␉␊
385 // Other status (e.g. 0) means that we should proceed with boot.␊
386␉␉␊
387␉␉// Turn off any GUI elements␊
388␉␉if( bootArgs->Video.v_display == GRAPHICS_MODE )␊
389␉␉{␊
390␉␉␉gui.devicelist.draw = false;␊
391␉␉␉gui.bootprompt.draw = false;␊
392␉␉␉gui.menu.draw = false;␊
393␉␉␉gui.infobox.draw = false;␊
394␉␉␉gui.logo.draw = false;␊
395␉␉␉drawBackground();␊
396␉␉␉updateVRAM();␊
397␉␉}␊
398␉␉␊
399␉␉// Find out which version mac os we're booting.␊
400␉␉if (!loadConfigFile("System/Library/CoreServices/SystemVersion.plist", &systemVersion)) {␊
401␉␉␉if (getValueForKey(kProductVersion, &val, &len, &systemVersion)) {␉␊
402␉␉␉␉// getValueForKey uses const char for val␊
403␉␉␉␉// so copy it and trim␊
404␉␉␉␉strncat(gMacOSVersion, val, MIN(len, 4));␊
405␉␉␉}␊
406␉␉}␊
407␊
408␉␉if (platformCPUFeature(CPU_FEATURE_EM64T)) {␊
409␉␉␉archCpuType = CPU_TYPE_X86_64;␊
410␉␉} else {␊
411␉␉␉archCpuType = CPU_TYPE_I386;␊
412␉␉}␊
413␉␉if (getValueForKey(karch, &val, &len, &bootInfo->bootConfig)) {␊
414␉␉␉if (strncmp(val, "i386", 4) == 0) {␊
415␉␉␉␉archCpuType = CPU_TYPE_I386;␊
416␉␉␉}␊
417␉␉}␊
418␊
419␉␉if (!getBoolForKey (kWake, &tryresume, &bootInfo->bootConfig)) {␊
420␉␉␉tryresume = true;␊
421␉␉␉tryresumedefault = true;␊
422␉␉} else {␊
423␉␉␉tryresumedefault = false;␊
424␉␉}␊
425␊
426␉␉if (!getBoolForKey (kForceWake, &forceresume, &bootInfo->bootConfig)) {␊
427␉␉␉forceresume = false;␊
428␉␉}␊
429␉␉␊
430␉␉if (forceresume) {␊
431␉␉␉tryresume = true;␊
432␉␉␉tryresumedefault = false;␊
433␉␉}␊
434␉␉␊
435␉␉while (tryresume) {␊
436␉␉␉const char *tmp;␊
437␉␉␉BVRef bvr;␊
438␉␉␉if (!getValueForKey(kWakeImage, &val, &len, &bootInfo->bootConfig))␊
439␉␉␉␉val="/private/var/vm/sleepimage";␊
440␉␉␉␊
441␉␉␉// Do this first to be sure that root volume is mounted␊
442␉␉␉ret = GetFileInfo(0, val, &flags, &sleeptime);␊
443␊
444␉␉␉if ((bvr = getBootVolumeRef(val, &tmp)) == NULL)␊
445␉␉␉␉break;␊
446␉␉␉␊
447␉␉␉// Can't check if it was hibernation Wake=y is required␊
448␉␉␉if (bvr->modTime == 0 && tryresumedefault)␊
449␉␉␉␉break;␊
450␉␉␉␊
451␉␉␉if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat))␊
452␉␉␉␉break;␊
453␉␉␉␊
454␉␉␉if (!forceresume && ((sleeptime+3)<bvr->modTime)) {␊
455␉␉␉␉printf ("Hibernate image is too old by %d seconds. Use ForceWake=y to override\n",bvr->modTime-sleeptime);␊
456␉␉␉␉break;␊
457␉␉␉}␊
458␉␉␉␉␊
459␉␉␉HibernateBoot((char *)val);␊
460␉␉␉break;␊
461␉␉}␊
462␊
463 // Reset cache name.␊
464 bzero(gCacheNameAdler + 64, sizeof(gCacheNameAdler) - 64);␊
465␊
466 sprintf(gCacheNameAdler + 64, "%s,%s", gRootDevice, bootInfo->bootFile);␊
467␊
468 adler32 = Adler32((unsigned char *)gCacheNameAdler, sizeof(gCacheNameAdler));␊
469␊
470 if (getValueForKey(kKernelCacheKey, &val, &len, &bootInfo->bootConfig)) {␊
471 strlcpy(gBootKernelCacheFile, val, len+1);␊
472 } else {␊
473 sprintf(gBootKernelCacheFile, "%s.%08lX", kDefaultCachePath, adler32);␊
474 }␊
475␊
476 // Check for cache file.␊
477 trycache = (((gBootMode & kBootModeSafe) == 0) &&␊
478 !gOverrideKernel &&␊
479 (gBootFileType == kBlockDeviceType) &&␊
480 (gMKextName[0] == '\0') &&␊
481 (gBootKernelCacheFile[0] != '\0'));␊
482␊
483␉␉verbose("Loading Darwin %s\n", gMacOSVersion);␊
484␉␉␊
485 if (trycache) do {␊
486 ␊
487 // if we haven't found the kernel yet, don't use the cache␊
488 ret = GetFileInfo(NULL, bootInfo->bootFile, &flags, &kerneltime);␊
489 if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat)) {␊
490 trycache = 0;␊
491 break;␊
492 }␊
493 ret = GetFileInfo(NULL, gBootKernelCacheFile, &flags, &cachetime);␊
494 if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat)␊
495 || (cachetime < kerneltime)) {␊
496 trycache = 0;␊
497 break;␊
498 }␊
499 ret = GetFileInfo("/System/Library/", "Extensions", &flags, &exttime);␊
500 if ((ret == 0) && ((flags & kFileTypeMask) == kFileTypeDirectory)␊
501 && (cachetime < exttime)) {␊
502 trycache = 0;␊
503 break;␊
504 }␊
505 if (kerneltime > exttime) {␊
506 exttime = kerneltime;␊
507 }␊
508 if (cachetime != (exttime + 1)) {␊
509 trycache = 0;␊
510 break;␊
511 }␊
512 } while (0);␊
513␊
514 do {␊
515 if (trycache) {␊
516 bootFile = gBootKernelCacheFile;␊
517 verbose("Loading kernel cache %s\n", bootFile);␊
518 ret = LoadFile(bootFile);␊
519 binary = (void *)kLoadAddr;␊
520 if (ret >= 0) {␊
521 break;␊
522 }␊
523 }␊
524 bootFile = bootInfo->bootFile;␊
525␊
526 // Try to load kernel image from alternate locations on boot helper partitions.␊
527 sprintf(bootFileSpec, "com.apple.boot.P/%s", bootFile);␊
528 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
529 ␉ ␉ if (ret == -1)␊
530 ␉ ␉ {␊
531 sprintf(bootFileSpec, "com.apple.boot.R/%s", bootFile);␊
532 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
533 if (ret == -1)␊
534 {␊
535 sprintf(bootFileSpec, "com.apple.boot.S/%s", bootFile);␊
536 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
537 if (ret == -1)␊
538 {␊
539 // Not found any alternate locations, using the original kernel image path.␊
540 strcpy(bootFileSpec, bootFile);␊
541 }␊
542 }␊
543 }␊
544 ␉␉␉␊
545 verbose("Loading kernel %s\n", bootFileSpec);␊
546 ret = LoadThinFatFile(bootFileSpec, &binary);␊
547 if (ret <= 0 && archCpuType == CPU_TYPE_X86_64)␊
548 {␊
549 archCpuType = CPU_TYPE_I386;␊
550 ret = LoadThinFatFile(bootFileSpec, &binary);␉␉␉␉␊
551 }␊
552␉␉␉␊
553 } while (0);␊
554␊
555 clearActivityIndicator();␊
556#if DEBUG␊
557 printf("Pausing...");␊
558 sleep(8);␊
559#endif␊
560␊
561 if (ret <= 0) {␊
562␉␉␉printf("Can't find %s\n", bootFile);␊
563␊
564␉␉␉sleep(1);␊
565␊
566 if (gBootFileType == kNetworkDeviceType) {␊
567 // Return control back to PXE. Don't unload PXE base code.␊
568 gUnloadPXEOnExit = false;␊
569 break;␊
570 }␊
571 } else {␊
572 /* Won't return if successful. */␊
573 ret = ExecKernel(binary);␊
574 }␊
575 }␊
576 ␊
577 // chainboot␊
578 if (status==1) {␊
579␉if (getVideoMode() == GRAPHICS_MODE) {␉// if we are already in graphics-mode,␊
580␉␉setVideoMode(VGA_TEXT_MODE, 0);␉// switch back to text mode␊
581␉}␊
582 }␊
583␉␊
584 if ((gBootFileType == kNetworkDeviceType) && gUnloadPXEOnExit) {␊
585␉nbpUnloadBaseCode();␊
586 }␊
587}␊
588␊
589/*!␊
590 Selects a new BIOS device, taking care to update the global state appropriately.␊
591 */␊
592/*␊
593static void selectBiosDevice(void)␊
594{␊
595 struct DiskBVMap *oldMap = diskResetBootVolumes(gBIOSDev);␊
596 CacheReset();␊
597 diskFreeMap(oldMap);␊
598 oldMap = NULL;␊
599␊
600 int dev = selectAlternateBootDevice(gBIOSDev);␊
601␊
602 BVRef bvchain = scanBootVolumes(dev, 0);␊
603 BVRef bootVol = selectBootVolume(bvchain);␊
604 gBootVolume = bootVol;␊
605 setRootVolume(bootVol);␊
606 gBIOSDev = dev;␊
607}␊
608*/␊
609␊
610#define BASE 65521L /* largest prime smaller than 65536 */␊
611#define NMAX 5000␊
612// NMAX (was 5521) the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1␊
613␊
614#define DO1(buf,i) {s1 += buf[i]; s2 += s1;}␊
615#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);␊
616#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);␊
617#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);␊
618#define DO16(buf) DO8(buf,0); DO8(buf,8);␊
619␊
620unsigned long Adler32(unsigned char *buf, long len)␊
621{␊
622 unsigned long s1 = 1; // adler & 0xffff;␊
623 unsigned long s2 = 0; // (adler >> 16) & 0xffff;␊
624 unsigned long result;␊
625 int k;␊
626␊
627 while (len > 0) {␊
628 k = len < NMAX ? len : NMAX;␊
629 len -= k;␊
630 while (k >= 16) {␊
631 DO16(buf);␊
632 buf += 16;␊
633 k -= 16;␊
634 }␊
635 if (k != 0) do {␊
636 s1 += *buf++;␊
637 s2 += s1;␊
638 } while (--k);␊
639 s1 %= BASE;␊
640 s2 %= BASE;␊
641 }␊
642 result = (s2 << 16) | s1;␊
643 return OSSwapHostToBigInt32(result);␊
644}␊
645

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