compiler-rt/lib/builtins/os_version_check.c

   1 //===-- os_version_check.c - OS version checking  -------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the function __isOSVersionAtLeast, used by
  10 // Objective-C's @available
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifdef __APPLE__
  15
  16 #include <TargetConditionals.h>
  17 #include <dispatch/dispatch.h>
  18 #include <dlfcn.h>
  19 #include <stdint.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 // These three variables hold the host's OS version.
  25 static int32_t GlobalMajor, GlobalMinor, GlobalSubminor;
  26 static dispatch_once_t DispatchOnceCounter;
  27 static dispatch_once_t CompatibilityDispatchOnceCounter;
  28
  29 // _availability_version_check darwin API support.
  30 typedef uint32_t dyld_platform_t;
  31
  32 typedef struct {
  33   dyld_platform_t platform;
  34   uint32_t version;
  35 } dyld_build_version_t;
  36
  37 typedef bool (*AvailabilityVersionCheckFuncTy)(uint32_t count,
  38                                                dyld_build_version_t versions[]);
  39
  40 static AvailabilityVersionCheckFuncTy AvailabilityVersionCheck;
  41
  42 // We can't include <CoreFoundation/CoreFoundation.h> directly from here, so
  43 // just forward declare everything that we need from it.
  44
  45 typedef const void *CFDataRef, *CFAllocatorRef, *CFPropertyListRef,
  46     *CFStringRef, *CFDictionaryRef, *CFTypeRef, *CFErrorRef;
  47
  48 #if __LLP64__
  49 typedef unsigned long long CFTypeID;
  50 typedef unsigned long long CFOptionFlags;
  51 typedef signed long long CFIndex;
  52 #else
  53 typedef unsigned long CFTypeID;
  54 typedef unsigned long CFOptionFlags;
  55 typedef signed long CFIndex;
  56 #endif
  57
  58 typedef unsigned char UInt8;
  59 typedef _Bool Boolean;
  60 typedef CFIndex CFPropertyListFormat;
  61 typedef uint32_t CFStringEncoding;
  62
  63 // kCFStringEncodingASCII analog.
  64 #define CF_STRING_ENCODING_ASCII 0x0600
  65 // kCFStringEncodingUTF8 analog.
  66 #define CF_STRING_ENCODING_UTF8 0x08000100
  67 #define CF_PROPERTY_LIST_IMMUTABLE 0
  68
  69 typedef CFDataRef (*CFDataCreateWithBytesNoCopyFuncTy)(CFAllocatorRef,
  70                                                        const UInt8 *, CFIndex,
  71                                                        CFAllocatorRef);
  72 typedef CFPropertyListRef (*CFPropertyListCreateWithDataFuncTy)(
  73     CFAllocatorRef, CFDataRef, CFOptionFlags, CFPropertyListFormat *,
  74     CFErrorRef *);
  75 typedef CFPropertyListRef (*CFPropertyListCreateFromXMLDataFuncTy)(
  76     CFAllocatorRef, CFDataRef, CFOptionFlags, CFStringRef *);
  77 typedef CFStringRef (*CFStringCreateWithCStringNoCopyFuncTy)(CFAllocatorRef,
  78                                                              const char *,
  79                                                              CFStringEncoding,
  80                                                              CFAllocatorRef);
  81 typedef const void *(*CFDictionaryGetValueFuncTy)(CFDictionaryRef,
  82                                                   const void *);
  83 typedef CFTypeID (*CFGetTypeIDFuncTy)(CFTypeRef);
  84 typedef CFTypeID (*CFStringGetTypeIDFuncTy)(void);
  85 typedef Boolean (*CFStringGetCStringFuncTy)(CFStringRef, char *, CFIndex,
  86                                             CFStringEncoding);
  87 typedef void (*CFReleaseFuncTy)(CFTypeRef);
  88
  89 extern __attribute__((weak_import))
  90 bool _availability_version_check(uint32_t count,
  91                                  dyld_build_version_t versions[]);
  92
  93 static void _initializeAvailabilityCheck(bool LoadPlist) {
  94   if (AvailabilityVersionCheck && !LoadPlist) {
  95     // New API is supported and we're not being asked to load the plist,
  96     // exit early!
  97     return;
  98   }
  99
 100   // Use the new API if it's is available.
 101   if (_availability_version_check)
 102     AvailabilityVersionCheck = &_availability_version_check;
 103
 104   if (AvailabilityVersionCheck && !LoadPlist) {
 105     // New API is supported and we're not being asked to load the plist,
 106     // exit early!
 107     return;
 108   }
 109   // Still load the PLIST to ensure that the existing calls to
 110   // __isOSVersionAtLeast still work even with new compiler-rt and old OSes.
 111
 112   // Load CoreFoundation dynamically
 113   const void *NullAllocator = dlsym(RTLD_DEFAULT, "kCFAllocatorNull");
 114   if (!NullAllocator)
 115     return;
 116   const CFAllocatorRef AllocatorNull = *(const CFAllocatorRef *)NullAllocator;
 117   CFDataCreateWithBytesNoCopyFuncTy CFDataCreateWithBytesNoCopyFunc =
 118       (CFDataCreateWithBytesNoCopyFuncTy)dlsym(RTLD_DEFAULT,
 119                                                "CFDataCreateWithBytesNoCopy");
 120   if (!CFDataCreateWithBytesNoCopyFunc)
 121     return;
 122   CFPropertyListCreateWithDataFuncTy CFPropertyListCreateWithDataFunc =
 123       (CFPropertyListCreateWithDataFuncTy)dlsym(RTLD_DEFAULT,
 124                                                 "CFPropertyListCreateWithData");
 125 // CFPropertyListCreateWithData was introduced only in macOS 10.6+, so it
 126 // will be NULL on earlier OS versions.
 127 #pragma clang diagnostic push
 128 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
 129   CFPropertyListCreateFromXMLDataFuncTy CFPropertyListCreateFromXMLDataFunc =
 130       (CFPropertyListCreateFromXMLDataFuncTy)dlsym(
 131           RTLD_DEFAULT, "CFPropertyListCreateFromXMLData");
 132 #pragma clang diagnostic pop
 133   // CFPropertyListCreateFromXMLDataFunc is deprecated in macOS 10.10, so it
 134   // might be NULL in future OS versions.
 135   if (!CFPropertyListCreateWithDataFunc && !CFPropertyListCreateFromXMLDataFunc)
 136     return;
 137   CFStringCreateWithCStringNoCopyFuncTy CFStringCreateWithCStringNoCopyFunc =
 138       (CFStringCreateWithCStringNoCopyFuncTy)dlsym(
 139           RTLD_DEFAULT, "CFStringCreateWithCStringNoCopy");
 140   if (!CFStringCreateWithCStringNoCopyFunc)
 141     return;
 142   CFDictionaryGetValueFuncTy CFDictionaryGetValueFunc =
 143       (CFDictionaryGetValueFuncTy)dlsym(RTLD_DEFAULT, "CFDictionaryGetValue");
 144   if (!CFDictionaryGetValueFunc)
 145     return;
 146   CFGetTypeIDFuncTy CFGetTypeIDFunc =
 147       (CFGetTypeIDFuncTy)dlsym(RTLD_DEFAULT, "CFGetTypeID");
 148   if (!CFGetTypeIDFunc)
 149     return;
 150   CFStringGetTypeIDFuncTy CFStringGetTypeIDFunc =
 151       (CFStringGetTypeIDFuncTy)dlsym(RTLD_DEFAULT, "CFStringGetTypeID");
 152   if (!CFStringGetTypeIDFunc)
 153     return;
 154   CFStringGetCStringFuncTy CFStringGetCStringFunc =
 155       (CFStringGetCStringFuncTy)dlsym(RTLD_DEFAULT, "CFStringGetCString");
 156   if (!CFStringGetCStringFunc)
 157     return;
 158   CFReleaseFuncTy CFReleaseFunc =
 159       (CFReleaseFuncTy)dlsym(RTLD_DEFAULT, "CFRelease");
 160   if (!CFReleaseFunc)
 161     return;
 162
 163   char *PListPath = "/System/Library/CoreServices/SystemVersion.plist";
 164
 165 #if TARGET_OS_SIMULATOR
 166   char *PListPathPrefix = getenv("IPHONE_SIMULATOR_ROOT");
 167   if (!PListPathPrefix)
 168     return;
 169   char FullPath[strlen(PListPathPrefix) + strlen(PListPath) + 1];
 170   strcpy(FullPath, PListPathPrefix);
 171   strcat(FullPath, PListPath);
 172   PListPath = FullPath;
 173 #endif
 174   FILE *PropertyList = fopen(PListPath, "r");
 175   if (!PropertyList)
 176     return;
 177
 178   // Dynamically allocated stuff.
 179   CFDictionaryRef PListRef = NULL;
 180   CFDataRef FileContentsRef = NULL;
 181   UInt8 *PListBuf = NULL;
 182
 183   fseek(PropertyList, 0, SEEK_END);
 184   long PListFileSize = ftell(PropertyList);
 185   if (PListFileSize < 0)
 186     goto Fail;
 187   rewind(PropertyList);
 188
 189   PListBuf = malloc((size_t)PListFileSize);
 190   if (!PListBuf)
 191     goto Fail;
 192
 193   size_t NumRead = fread(PListBuf, 1, (size_t)PListFileSize, PropertyList);
 194   if (NumRead != (size_t)PListFileSize)
 195     goto Fail;
 196
 197   // Get the file buffer into CF's format. We pass in a null allocator here *
 198   // because we free PListBuf ourselves
 199   FileContentsRef = (*CFDataCreateWithBytesNoCopyFunc)(
 200       NULL, PListBuf, (CFIndex)NumRead, AllocatorNull);
 201   if (!FileContentsRef)
 202     goto Fail;
 203
 204   if (CFPropertyListCreateWithDataFunc)
 205     PListRef = (*CFPropertyListCreateWithDataFunc)(
 206         NULL, FileContentsRef, CF_PROPERTY_LIST_IMMUTABLE, NULL, NULL);
 207   else
 208     PListRef = (*CFPropertyListCreateFromXMLDataFunc)(
 209         NULL, FileContentsRef, CF_PROPERTY_LIST_IMMUTABLE, NULL);
 210   if (!PListRef)
 211     goto Fail;
 212
 213   CFStringRef ProductVersion = (*CFStringCreateWithCStringNoCopyFunc)(
 214       NULL, "ProductVersion", CF_STRING_ENCODING_ASCII, AllocatorNull);
 215   if (!ProductVersion)
 216     goto Fail;
 217   CFTypeRef OpaqueValue = (*CFDictionaryGetValueFunc)(PListRef, ProductVersion);
 218   (*CFReleaseFunc)(ProductVersion);
 219   if (!OpaqueValue ||
 220       (*CFGetTypeIDFunc)(OpaqueValue) != (*CFStringGetTypeIDFunc)())
 221     goto Fail;
 222
 223   char VersionStr[32];
 224   if (!(*CFStringGetCStringFunc)((CFStringRef)OpaqueValue, VersionStr,
 225                                  sizeof(VersionStr), CF_STRING_ENCODING_UTF8))
 226     goto Fail;
 227   sscanf(VersionStr, "%d.%d.%d", &GlobalMajor, &GlobalMinor, &GlobalSubminor);
 228
 229 Fail:
 230   if (PListRef)
 231     (*CFReleaseFunc)(PListRef);
 232   if (FileContentsRef)
 233     (*CFReleaseFunc)(FileContentsRef);
 234   free(PListBuf);
 235   fclose(PropertyList);
 236 }
 237
 238 // Find and parse the SystemVersion.plist file.
 239 static void compatibilityInitializeAvailabilityCheck(void *Unused) {
 240   (void)Unused;
 241   _initializeAvailabilityCheck(/*LoadPlist=*/true);
 242 }
 243
 244 static void initializeAvailabilityCheck(void *Unused) {
 245   (void)Unused;
 246   _initializeAvailabilityCheck(/*LoadPlist=*/false);
 247 }
 248
 249 // This old API entry point is no longer used by Clang for Darwin. We still need
 250 // to keep it around to ensure that object files that reference it are still
 251 // usable when linked with new compiler-rt.
 252 int32_t __isOSVersionAtLeast(int32_t Major, int32_t Minor, int32_t Subminor) {
 253   // Populate the global version variables, if they haven't already.
 254   dispatch_once_f(&CompatibilityDispatchOnceCounter, NULL,
 255                   compatibilityInitializeAvailabilityCheck);
 256
 257   if (Major < GlobalMajor)
 258     return 1;
 259   if (Major > GlobalMajor)
 260     return 0;
 261   if (Minor < GlobalMinor)
 262     return 1;
 263   if (Minor > GlobalMinor)
 264     return 0;
 265   return Subminor <= GlobalSubminor;
 266 }
 267
 268 static inline uint32_t ConstructVersion(uint32_t Major, uint32_t Minor,
 269                                         uint32_t Subminor) {
 270   return ((Major & 0xffff) << 16) | ((Minor & 0xff) << 8) | (Subminor & 0xff);
 271 }
 272
 273 int32_t __isPlatformVersionAtLeast(uint32_t Platform, uint32_t Major,
 274                                    uint32_t Minor, uint32_t Subminor) {
 275   dispatch_once_f(&DispatchOnceCounter, NULL, initializeAvailabilityCheck);
 276
 277   if (!AvailabilityVersionCheck) {
 278     return __isOSVersionAtLeast(Major, Minor, Subminor);
 279   }
 280   dyld_build_version_t Versions[] = {
 281       {Platform, ConstructVersion(Major, Minor, Subminor)}};
 282   return AvailabilityVersionCheck(1, Versions);
 283 }
 284
 285 #elif __ANDROID__
 286
 287 #include <pthread.h>
 288 #include <stdlib.h>
 289 #include <string.h>
 290 #include <sys/system_properties.h>
 291
 292 static int SdkVersion;
 293 static int IsPreRelease;
 294
 295 static void readSystemProperties(void) {
 296   char buf[PROP_VALUE_MAX];
 297
 298   if (__system_property_get("ro.build.version.sdk", buf) == 0) {
 299     // When the system property doesn't exist, defaults to future API level.
 300     SdkVersion = __ANDROID_API_FUTURE__;
 301   } else {
 302     SdkVersion = atoi(buf);
 303   }
 304
 305   if (__system_property_get("ro.build.version.codename", buf) == 0) {
 306     IsPreRelease = 1;
 307   } else {
 308     IsPreRelease = strcmp(buf, "REL") != 0;
 309   }
 310   return;
 311 }
 312
 313 int32_t __isOSVersionAtLeast(int32_t Major, int32_t Minor, int32_t Subminor) {
 314   (void) Minor;
 315   (void) Subminor;
 316   static pthread_once_t once = PTHREAD_ONCE_INIT;
 317   pthread_once(&once, readSystemProperties);
 318
 319   return SdkVersion >= Major ||
 320          (IsPreRelease && Major == __ANDROID_API_FUTURE__);
 321 }
 322
 323 #else
 324
 325 // Silence an empty translation unit warning.
 326 typedef int unused;
 327
 328 #endif