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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 verbose("Starting Darwin %s\n",( archCpuType == CPU_TYPE_I386 ) ? "x86" : "x86_64");␊
166␊
167 // Cleanup the PXE base code.␊
168␊
169 if ( (gBootFileType == kNetworkDeviceType) && gUnloadPXEOnExit ) {␊
170␉␉if ( (ret = nbpUnloadBaseCode()) != nbpStatusSuccess )␊
171 {␊
172 ␉printf("nbpUnloadBaseCode error %d\n", (int) ret);␊
173 sleep(2);␊
174 }␊
175 }␊
176␊
177 bool dummyVal;␊
178 if (getBoolForKey(kWaitForKeypressKey, &dummyVal, &bootInfo->bootConfig) && dummyVal) {␊
179␉printf("Press any key to continue...");␊
180␉getc();␊
181 }␊
182␊
183 // If we were in text mode, switch to graphics mode.␊
184 // This will draw the boot graphics unless we are in␊
185 // verbose mode.␊
186␊
187 if(gVerboseMode)␊
188 setVideoMode( GRAPHICS_MODE, 0 );␊
189 else␊
190 drawBootGraphics();␊
191␉␊
192 finalizeBootStruct();␊
193 ␊
194 // Jump to kernel's entry point. There's no going back now.␊
195␊
196 startprog( kernelEntry, bootArgs );␊
197␊
198 // Not reached␊
199␊
200 return 0;␊
201}␊
202␊
203//==========================================================================␊
204// This is the entrypoint from real-mode which functions exactly as it did␊
205// before. Multiboot does its own runtime initialization, does some of its␊
206// own things, and then calls common_boot.␊
207void boot(int biosdev)␊
208{␊
209␉initialize_runtime();␊
210␉// Enable A20 gate before accessing memory above 1Mb.␊
211␉enableA20();␊
212␉common_boot(biosdev);␊
213}␊
214␊
215//==========================================================================␊
216// The 'main' function for the booter. Called by boot0 when booting␊
217// from a block device, or by the network booter.␊
218//␊
219// arguments:␊
220// biosdev - Value passed from boot1/NBP to specify the device␊
221// that the booter was loaded from.␊
222//␊
223// If biosdev is kBIOSDevNetwork, then this function will return if␊
224// booting was unsuccessful. This allows the PXE firmware to try the␊
225// next boot device on its list.␊
226void common_boot(int biosdev)␊
227{␊
228 int status;␊
229 char *bootFile;␊
230 unsigned long adler32;␊
231 bool quiet;␊
232 bool firstRun = true;␊
233 bool instantMenu;␊
234 bool rescanPrompt;␊
235 unsigned int allowBVFlags = kBVFlagSystemVolume|kBVFlagForeignBoot;␊
236 unsigned int denyBVFlags = kBVFlagEFISystem;␊
237␊
238 // Set reminder to unload the PXE base code. Neglect to unload␊
239 // the base code will result in a hang or kernel panic.␊
240 gUnloadPXEOnExit = true;␊
241␊
242 // Record the device that the booter was loaded from.␊
243 gBIOSDev = biosdev & kBIOSDevMask;␊
244␊
245 // Initialize boot info structure.␊
246 initKernBootStruct();␊
247␊
248 // Setup VGA text mode.␊
249 // Not sure if it is safe to call setVideoMode() before the␊
250 // config table has been loaded. Call video_mode() instead.␊
251#if DEBUG␊
252 printf("before video_mode\n");␊
253#endif␊
254 video_mode( 2 ); // 80x25 mono text mode.␊
255#if DEBUG␊
256 printf("after video_mode\n");␊
257#endif␊
258␊
259 // Scan and record the system's hardware information.␊
260 scan_platform();␊
261␊
262 // First get info for boot volume.␊
263 scanBootVolumes(gBIOSDev, 0);␊
264 bvChain = getBVChainForBIOSDev(gBIOSDev);␊
265 setBootGlobals(bvChain);␊
266 ␊
267 // Load boot.plist config file␊
268 status = loadSystemConfig(&bootInfo->bootConfig);␊
269␊
270 if (getBoolForKey(kQuietBootKey, &quiet, &bootInfo->bootConfig) && quiet) {␊
271 gBootMode |= kBootModeQuiet;␊
272 }␊
273␊
274 // Override firstRun to get to the boot menu instantly by setting "Instant Menu"=y in system config␊
275 if (getBoolForKey(kInsantMenuKey, &instantMenu, &bootInfo->bootConfig) && instantMenu) {␊
276 firstRun = false;␊
277 }␊
278␊
279 // Loading preboot ramdisk if exists.␊
280 loadPrebootRAMDisk();␊
281␊
282 // Disable rescan option by default␊
283 gEnableCDROMRescan = false;␊
284␊
285 // Enable it with Rescan=y in system config␊
286 if (getBoolForKey(kRescanKey, &gEnableCDROMRescan, &bootInfo->bootConfig) && gEnableCDROMRescan) {␊
287 gEnableCDROMRescan = true;␊
288 }␊
289␊
290 // Ask the user for Rescan option by setting "Rescan Prompt"=y in system config.␊
291 rescanPrompt = false;␊
292 if (getBoolForKey(kRescanPromptKey, &rescanPrompt , &bootInfo->bootConfig) && rescanPrompt && biosDevIsCDROM(gBIOSDev)) {␊
293 gEnableCDROMRescan = promptForRescanOption();␊
294 }␊
295␊
296 // Enable touching a single BIOS device only if "Scan Single Drive"=y is set in system config.␊
297 if (getBoolForKey(kScanSingleDriveKey, &gScanSingleDrive, &bootInfo->bootConfig) && gScanSingleDrive) {␊
298 gScanSingleDrive = true;␊
299 }␊
300␊
301 // Create a list of partitions on device(s).␊
302 if (gScanSingleDrive) {␊
303 scanBootVolumes(gBIOSDev, &bvCount);␊
304 } else {␊
305 scanDisks(gBIOSDev, &bvCount);␊
306 }␊
307␊
308 // Create a separated bvr chain using the specified filters.␊
309 bvChain = newFilteredBVChain(0x80, 0xFF, allowBVFlags, denyBVFlags, &gDeviceCount);␊
310␊
311 gBootVolume = selectBootVolume(bvChain);␊
312␊
313#if DEBUG␊
314 printf(" Default: %d, ->biosdev: %d, ->part_no: %d ->flags: %d\n", gBootVolume, gBootVolume->biosdev, gBootVolume->part_no, gBootVolume->flags);␊
315 printf(" bt(0,0): %d, ->biosdev: %d, ->part_no: %d ->flags: %d\n", gBIOSBootVolume, gBIOSBootVolume->biosdev, gBIOSBootVolume->part_no, gBIOSBootVolume->flags);␊
316 getc();␊
317#endif␊
318␊
319 useGUI = true;␊
320 // Override useGUI default␊
321 getBoolForKey(kGUIKey, &useGUI, &bootInfo->bootConfig);␊
322 if (useGUI) {␊
323 /* XXX AsereBLN handle error */␊
324␉initGUI();␊
325 }␊
326␊
327 setBootGlobals(bvChain);␊
328␊
329 // Parse args, load and start kernel.␊
330 while (1) {␊
331 const char *val;␊
332 int len;␊
333 int trycache;␊
334 long flags, cachetime, kerneltime, exttime, sleeptime, time;␊
335 int ret = -1;␊
336 void *binary = (void *)kLoadAddr;␊
337 bool tryresume;␊
338 bool tryresumedefault;␊
339 bool forceresume;␊
340␊
341 config_file_t systemVersion;␉␉// system.plist of booting partition␊
342␊
343 // additional variable for testing alternate kernel image locations on boot helper partitions.␊
344 char bootFileSpec[512];␊
345␉␉␊
346 // Initialize globals.␊
347␊
348 sysConfigValid = false;␊
349 gErrors = false;␊
350␊
351 status = getBootOptions(firstRun);␊
352 firstRun = false;␊
353 if (status == -1) continue;␊
354␉␉ ␊
355 status = processBootOptions();␊
356 // Status==1 means to chainboot␊
357 if ( status == 1 ) break;␊
358 // Status==-1 means that the config file couldn't be loaded or that gBootVolume is NULL␊
359 if ( status == -1 )␊
360 {␊
361 // gBootVolume == NULL usually means the user hit escape.␊
362 if(gBootVolume == NULL)␊
363 {␊
364 freeFilteredBVChain(bvChain);␊
365␊
366 if (gEnableCDROMRescan)␊
367 rescanBIOSDevice(gBIOSDev);␊
368 ␊
369 bvChain = newFilteredBVChain(0x80, 0xFF, allowBVFlags, denyBVFlags, &gDeviceCount);␊
370 setBootGlobals(bvChain);␊
371 }␊
372 continue;␊
373 }␊
374␉␉␊
375 // Other status (e.g. 0) means that we should proceed with boot.␊
376␉␉␊
377␉␉if( bootArgs->Video.v_display == GRAPHICS_MODE )␊
378␉␉␉drawBackground();␊
379␉␉␉␊
380 // Found and loaded a config file. Proceed with boot.␊
381␊
382␉␉// Turn off any GUI elements␊
383␉␉if( bootArgs->Video.v_display == GRAPHICS_MODE )␊
384␉␉{␊
385␉␉␉gui.devicelist.draw = false;␊
386␉␉␉gui.bootprompt.draw = false;␊
387␉␉␉gui.menu.draw = false;␊
388␉␉␉gui.infobox.draw = false;␊
389␉␉␉drawBackground();␊
390␉␉␉updateVRAM();␊
391␉␉}␊
392␉␉␊
393␉␉// Find out which version mac os we're booting.␊
394␉␉if (!loadConfigFile("System/Library/CoreServices/SystemVersion.plist", &systemVersion)) {␊
395␉␉␉if (getValueForKey(kProductVersion, &val, &len, &systemVersion)) {␉␊
396␉␉␉␉// getValueForKey uses const char for val␊
397␉␉␉␉// so copy it and trim␊
398␉␉␉␉strncpy(gMacOSVersion, val, MIN(len, 4));␊
399␉␉␉␉gMacOSVersion[MIN(len, 4)] = '\0';␊
400␉␉␉}␊
401␉␉}␊
402␊
403␉␉if (platformCPUFeature(CPU_FEATURE_EM64T)) {␊
404␉␉␉archCpuType = CPU_TYPE_X86_64;␊
405␉␉} else {␊
406␉␉␉archCpuType = CPU_TYPE_I386;␊
407␉␉}␊
408␉␉if (getValueForKey(karch, &val, &len, &bootInfo->bootConfig)) {␊
409␉␉␉if (strncmp(val, "i386", 4) == 0) {␊
410␉␉␉␉archCpuType = CPU_TYPE_I386;␊
411␉␉␉}␊
412␉␉}␊
413␉␉if (getValueForKey(k32BitModeFlag, &val, &len, &bootInfo->bootConfig)) {␊
414␉␉␉archCpuType = CPU_TYPE_I386;␊
415␉␉}␊
416␉␉␊
417␉␉if (!getBoolForKey (kWake, &tryresume, &bootInfo->bootConfig)) {␊
418␉␉␉tryresume = true;␊
419␉␉␉tryresumedefault = true;␊
420␉␉} else {␊
421␉␉␉tryresumedefault = false;␊
422␉␉}␊
423␊
424␉␉if (!getBoolForKey (kForceWake, &forceresume, &bootInfo->bootConfig)) {␊
425␉␉␉forceresume = false;␊
426␉␉}␊
427␉␉␊
428␉␉if (forceresume) {␊
429␉␉␉tryresume = true;␊
430␉␉␉tryresumedefault = false;␊
431␉␉}␊
432␉␉␊
433␉␉while (tryresume) {␊
434␉␉␉const char *tmp;␊
435␉␉␉BVRef bvr;␊
436␉␉␉if (!getValueForKey(kWakeImage, &val, &len, &bootInfo->bootConfig))␊
437␉␉␉␉val="/private/var/vm/sleepimage";␊
438␉␉␉␊
439␉␉␉// Do this first to be sure that root volume is mounted␊
440␉␉␉ret = GetFileInfo(0, val, &flags, &sleeptime);␊
441␊
442␉␉␉if ((bvr = getBootVolumeRef(val, &tmp)) == NULL)␊
443␉␉␉␉break;␊
444␉␉␉␊
445␉␉␉// Can't check if it was hibernation Wake=y is required␊
446␉␉␉if (bvr->modTime == 0 && tryresumedefault)␊
447␉␉␉␉break;␊
448␉␉␉␊
449␉␉␉if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat))␊
450␉␉␉␉break;␊
451␉␉␉␊
452␉␉␉if (!forceresume && sleeptime+3<bvr->modTime) {␊
453␉␉␉␉printf ("Hibernate image is too old by %d seconds. Use ForceWake=y to override\n",bvr->modTime-sleeptime);␊
454␉␉␉␉break;␊
455␉␉␉}␊
456␉␉␉␉␊
457␉␉␉HibernateBoot((char *)val);␊
458␉␉␉break;␊
459␉␉}␊
460␊
461 // Reset cache name.␊
462 bzero(gCacheNameAdler + 64, sizeof(gCacheNameAdler) - 64);␊
463␊
464 sprintf(gCacheNameAdler + 64, "%s,%s", gRootDevice, bootInfo->bootFile);␊
465␊
466 adler32 = Adler32((unsigned char *)gCacheNameAdler, sizeof(gCacheNameAdler));␊
467␊
468 if (getValueForKey(kKernelCacheKey, &val, &len, &bootInfo->bootConfig)) {␊
469 strlcpy(gBootKernelCacheFile, val, len+1);␊
470 } else {␊
471 sprintf(gBootKernelCacheFile, "%s.%08lX", kDefaultCachePath, adler32);␊
472 }␊
473␊
474 // Check for cache file.␊
475 trycache = (((gBootMode & kBootModeSafe) == 0) &&␊
476 !gOverrideKernel &&␊
477 (gBootFileType == kBlockDeviceType) &&␊
478 (gMKextName[0] == '\0') &&␊
479 (gBootKernelCacheFile[0] != '\0'));␊
480␊
481␉␉verbose("Loading Darwin %s\n", gMacOSVersion);␊
482␉␉␊
483 if (trycache) do {␊
484 ␊
485 // if we haven't found the kernel yet, don't use the cache␊
486 ret = GetFileInfo(NULL, bootInfo->bootFile, &flags, &kerneltime);␊
487 if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat)) {␊
488 trycache = 0;␊
489 break;␊
490 }␊
491 ret = GetFileInfo(NULL, gBootKernelCacheFile, &flags, &cachetime);␊
492 if ((ret != 0) || ((flags & kFileTypeMask) != kFileTypeFlat)␊
493 || (cachetime < kerneltime)) {␊
494 trycache = 0;␊
495 break;␊
496 }␊
497 ret = GetFileInfo("/System/Library/", "Extensions", &flags, &exttime);␊
498 if ((ret == 0) && ((flags & kFileTypeMask) == kFileTypeDirectory)␊
499 && (cachetime < exttime)) {␊
500 trycache = 0;␊
501 break;␊
502 }␊
503 if (kerneltime > exttime) {␊
504 exttime = kerneltime;␊
505 }␊
506 if (cachetime != (exttime + 1)) {␊
507 trycache = 0;␊
508 break;␊
509 }␊
510 } while (0);␊
511␊
512 do {␊
513 if (trycache) {␊
514 bootFile = gBootKernelCacheFile;␊
515 verbose("Loading kernel cache %s\n", bootFile);␊
516 ret = LoadFile(bootFile);␊
517 binary = (void *)kLoadAddr;␊
518 if (ret >= 0) {␊
519 break;␊
520 }␊
521 }␊
522 bootFile = bootInfo->bootFile;␊
523␊
524 // Try to load kernel image from alternate locations on boot helper partitions.␊
525 sprintf(bootFileSpec, "com.apple.boot.P/%s", bootFile);␊
526 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
527 ␉ ␉ if (ret == -1)␊
528 ␉ ␉ {␊
529 sprintf(bootFileSpec, "com.apple.boot.R/%s", bootFile);␊
530 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
531 if (ret == -1)␊
532 {␊
533 sprintf(bootFileSpec, "com.apple.boot.S/%s", bootFile);␊
534 ret = GetFileInfo(NULL, bootFileSpec, &flags, &time); ␊
535 if (ret == -1)␊
536 {␊
537 // Not found any alternate locations, using the original kernel image path.␊
538 strcpy(bootFileSpec, bootFile);␊
539 }␊
540 }␊
541 }␊
542 ␉␉␉␊
543 verbose("Loading kernel %s\n", bootFileSpec);␊
544 ret = LoadThinFatFile(bootFileSpec, &binary);␊
545 if (ret <= 0 && archCpuType == CPU_TYPE_X86_64)␊
546 {␊
547 archCpuType = CPU_TYPE_I386;␊
548 ret = LoadThinFatFile(bootFileSpec, &binary);␉␉␉␉␊
549 }␊
550␉␉␉␊
551 } while (0);␊
552␊
553 clearActivityIndicator();␊
554#if DEBUG␊
555 printf("Pausing...");␊
556 sleep(8);␊
557#endif␊
558␊
559 if (ret <= 0) {␊
560␉␉␉printf("Can't find %s\n", bootFile);␊
561␊
562␉␉␉if(gui.initialised) {␊
563␉␉␉␉sleep(1);␊
564␉␉␉␉drawBackground();␊
565␉␉␉␉gui.devicelist.draw = true;␊
566␉␉␉␉gui.redraw = true;␊
567␉␉␉}␊
568 if (gBootFileType == kNetworkDeviceType) {␊
569 // Return control back to PXE. Don't unload PXE base code.␊
570 gUnloadPXEOnExit = false;␊
571 break;␊
572 }␊
573 } else {␊
574 /* Won't return if successful. */␊
575 ret = ExecKernel(binary);␊
576 }␊
577 }␊
578 ␊
579 // chainboot␊
580 if (status==1) {␊
581␉if (getVideoMode() == GRAPHICS_MODE) {␉// if we are already in graphics-mode,␊
582␉␉setVideoMode(VGA_TEXT_MODE, 0);␉// switch back to text mode␊
583␉}␊
584 }␊
585␉␊
586 if ((gBootFileType == kNetworkDeviceType) && gUnloadPXEOnExit) {␊
587␉nbpUnloadBaseCode();␊
588 }␊
589}␊
590␊
591/*!␊
592 Selects a new BIOS device, taking care to update the global state appropriately.␊
593 */␊
594/*␊
595static void selectBiosDevice(void)␊
596{␊
597 struct DiskBVMap *oldMap = diskResetBootVolumes(gBIOSDev);␊
598 CacheReset();␊
599 diskFreeMap(oldMap);␊
600 oldMap = NULL;␊
601␊
602 int dev = selectAlternateBootDevice(gBIOSDev);␊
603␊
604 BVRef bvchain = scanBootVolumes(dev, 0);␊
605 BVRef bootVol = selectBootVolume(bvchain);␊
606 gBootVolume = bootVol;␊
607 setRootVolume(bootVol);␊
608 gBIOSDev = dev;␊
609}␊
610*/␊
611␊
612#define BASE 65521L /* largest prime smaller than 65536 */␊
613#define NMAX 5000␊
614// NMAX (was 5521) the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1␊
615␊
616#define DO1(buf,i) {s1 += buf[i]; s2 += s1;}␊
617#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);␊
618#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);␊
619#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);␊
620#define DO16(buf) DO8(buf,0); DO8(buf,8);␊
621␊
622unsigned long Adler32(unsigned char *buf, long len)␊
623{␊
624 unsigned long s1 = 1; // adler & 0xffff;␊
625 unsigned long s2 = 0; // (adler >> 16) & 0xffff;␊
626 unsigned long result;␊
627 int k;␊
628␊
629 while (len > 0) {␊
630 k = len < NMAX ? len : NMAX;␊
631 len -= k;␊
632 while (k >= 16) {␊
633 DO16(buf);␊
634 buf += 16;␊
635 k -= 16;␊
636 }␊
637 if (k != 0) do {␊
638 s1 += *buf++;␊
639 s2 += s1;␊
640 } while (--k);␊
641 s1 %= BASE;␊
642 s2 %= BASE;␊
643 }␊
644 result = (s2 << 16) | s1;␊
645 return OSSwapHostToBigInt32(result);␊
646}␊
647

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