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 static void _initializeAvailabilityCheck(bool LoadPlist) {
  90   if (AvailabilityVersionCheck && !LoadPlist) {
  91     // New API is supported and we're not being asked to load the plist,
  92     // exit early!
  93     return;
  94   }
  95
  96   // Use the new API if it's is available.
  97   AvailabilityVersionCheck = (AvailabilityVersionCheckFuncTy)dlsym(
  98       RTLD_DEFAULT, "_availability_version_check");
  99
 100   if (AvailabilityVersionCheck && !LoadPlist) {
 101     // New API is supported and we're not being asked to load the plist,
 102     // exit early!
 103     return;
 104   }
 105   // Still load the PLIST to ensure that the existing calls to
 106   // __isOSVersionAtLeast still work even with new compiler-rt and old OSes.
 107
 108   // Load CoreFoundation dynamically
 109   const void *NullAllocator = dlsym(RTLD_DEFAULT, "kCFAllocatorNull");
 110   if (!NullAllocator)
 111     return;
 112   const CFAllocatorRef AllocatorNull = *(const CFAllocatorRef *)NullAllocator;
 113   CFDataCreateWithBytesNoCopyFuncTy CFDataCreateWithBytesNoCopyFunc =
 114       (CFDataCreateWithBytesNoCopyFuncTy)dlsym(RTLD_DEFAULT,
 115                                                "CFDataCreateWithBytesNoCopy");
 116   if (!CFDataCreateWithBytesNoCopyFunc)
 117     return;
 118   CFPropertyListCreateWithDataFuncTy CFPropertyListCreateWithDataFunc =
 119       (CFPropertyListCreateWithDataFuncTy)dlsym(RTLD_DEFAULT,
 120                                                 "CFPropertyListCreateWithData");
 121 // CFPropertyListCreateWithData was introduced only in macOS 10.6+, so it
 122 // will be NULL on earlier OS versions.
 123 #pragma clang diagnostic push
 124 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
 125   CFPropertyListCreateFromXMLDataFuncTy CFPropertyListCreateFromXMLDataFunc =
 126       (CFPropertyListCreateFromXMLDataFuncTy)dlsym(
 127           RTLD_DEFAULT, "CFPropertyListCreateFromXMLData");
 128 #pragma clang diagnostic pop
 129   // CFPropertyListCreateFromXMLDataFunc is deprecated in macOS 10.10, so it
 130   // might be NULL in future OS versions.
 131   if (!CFPropertyListCreateWithDataFunc && !CFPropertyListCreateFromXMLDataFunc)
 132     return;
 133   CFStringCreateWithCStringNoCopyFuncTy CFStringCreateWithCStringNoCopyFunc =
 134       (CFStringCreateWithCStringNoCopyFuncTy)dlsym(
 135           RTLD_DEFAULT, "CFStringCreateWithCStringNoCopy");
 136   if (!CFStringCreateWithCStringNoCopyFunc)
 137     return;
 138   CFDictionaryGetValueFuncTy CFDictionaryGetValueFunc =
 139       (CFDictionaryGetValueFuncTy)dlsym(RTLD_DEFAULT, "CFDictionaryGetValue");
 140   if (!CFDictionaryGetValueFunc)
 141     return;
 142   CFGetTypeIDFuncTy CFGetTypeIDFunc =
 143       (CFGetTypeIDFuncTy)dlsym(RTLD_DEFAULT, "CFGetTypeID");
 144   if (!CFGetTypeIDFunc)
 145     return;
 146   CFStringGetTypeIDFuncTy CFStringGetTypeIDFunc =
 147       (CFStringGetTypeIDFuncTy)dlsym(RTLD_DEFAULT, "CFStringGetTypeID");
 148   if (!CFStringGetTypeIDFunc)
 149     return;
 150   CFStringGetCStringFuncTy CFStringGetCStringFunc =
 151       (CFStringGetCStringFuncTy)dlsym(RTLD_DEFAULT, "CFStringGetCString");
 152   if (!CFStringGetCStringFunc)
 153     return;
 154   CFReleaseFuncTy CFReleaseFunc =
 155       (CFReleaseFuncTy)dlsym(RTLD_DEFAULT, "CFRelease");
 156   if (!CFReleaseFunc)
 157     return;
 158
 159   char *PListPath = "/System/Library/CoreServices/SystemVersion.plist";
 160
 161 #if TARGET_OS_SIMULATOR
 162   char *PListPathPrefix = getenv("IPHONE_SIMULATOR_ROOT");
 163   if (!PListPathPrefix)
 164     return;
 165   char FullPath[strlen(PListPathPrefix) + strlen(PListPath) + 1];
 166   strcpy(FullPath, PListPathPrefix);
 167   strcat(FullPath, PListPath);
 168   PListPath = FullPath;
 169 #endif
 170   FILE *PropertyList = fopen(PListPath, "r");
 171   if (!PropertyList)
 172     return;
 173
 174   // Dynamically allocated stuff.
 175   CFDictionaryRef PListRef = NULL;
 176   CFDataRef FileContentsRef = NULL;
 177   UInt8 *PListBuf = NULL;
 178
 179   fseek(PropertyList, 0, SEEK_END);
 180   long PListFileSize = ftell(PropertyList);
 181   if (PListFileSize < 0)
 182     goto Fail;
 183   rewind(PropertyList);
 184
 185   PListBuf = malloc((size_t)PListFileSize);
 186   if (!PListBuf)
 187     goto Fail;
 188
 189   size_t NumRead = fread(PListBuf, 1, (size_t)PListFileSize, PropertyList);
 190   if (NumRead != (size_t)PListFileSize)
 191     goto Fail;
 192
 193   // Get the file buffer into CF's format. We pass in a null allocator here *
 194   // because we free PListBuf ourselves
 195   FileContentsRef = (*CFDataCreateWithBytesNoCopyFunc)(
 196       NULL, PListBuf, (CFIndex)NumRead, AllocatorNull);
 197   if (!FileContentsRef)
 198     goto Fail;
 199
 200   if (CFPropertyListCreateWithDataFunc)
 201     PListRef = (*CFPropertyListCreateWithDataFunc)(
 202         NULL, FileContentsRef, CF_PROPERTY_LIST_IMMUTABLE, NULL, NULL);
 203   else
 204     PListRef = (*CFPropertyListCreateFromXMLDataFunc)(
 205         NULL, FileContentsRef, CF_PROPERTY_LIST_IMMUTABLE, NULL);
 206   if (!PListRef)
 207     goto Fail;
 208
 209   CFStringRef ProductVersion = (*CFStringCreateWithCStringNoCopyFunc)(
 210       NULL, "ProductVersion", CF_STRING_ENCODING_ASCII, AllocatorNull);
 211   if (!ProductVersion)
 212     goto Fail;
 213   CFTypeRef OpaqueValue = (*CFDictionaryGetValueFunc)(PListRef, ProductVersion);
 214   (*CFReleaseFunc)(ProductVersion);
 215   if (!OpaqueValue ||
 216       (*CFGetTypeIDFunc)(OpaqueValue) != (*CFStringGetTypeIDFunc)())
 217     goto Fail;
 218
 219   char VersionStr[32];
 220   if (!(*CFStringGetCStringFunc)((CFStringRef)OpaqueValue, VersionStr,
 221                                  sizeof(VersionStr), CF_STRING_ENCODING_UTF8))
 222     goto Fail;
 223   sscanf(VersionStr, "%d.%d.%d", &GlobalMajor, &GlobalMinor, &GlobalSubminor);
 224
 225 Fail:
 226   if (PListRef)
 227     (*CFReleaseFunc)(PListRef);
 228   if (FileContentsRef)
 229     (*CFReleaseFunc)(FileContentsRef);
 230   free(PListBuf);
 231   fclose(PropertyList);
 232 }
 233
 234 // Find and parse the SystemVersion.plist file.
 235 static void compatibilityInitializeAvailabilityCheck(void *Unused) {
 236   (void)Unused;
 237   _initializeAvailabilityCheck(/*LoadPlist=*/true);
 238 }
 239
 240 static void initializeAvailabilityCheck(void *Unused) {
 241   (void)Unused;
 242   _initializeAvailabilityCheck(/*LoadPlist=*/false);
 243 }
 244
 245 // This old API entry point is no longer used by Clang for Darwin. We still need
 246 // to keep it around to ensure that object files that reference it are still
 247 // usable when linked with new compiler-rt.
 248 int32_t __isOSVersionAtLeast(int32_t Major, int32_t Minor, int32_t Subminor) {
 249   // Populate the global version variables, if they haven't already.
 250   dispatch_once_f(&CompatibilityDispatchOnceCounter, NULL,
 251                   compatibilityInitializeAvailabilityCheck);
 252
 253   if (Major < GlobalMajor)
 254     return 1;
 255   if (Major > GlobalMajor)
 256     return 0;
 257   if (Minor < GlobalMinor)
 258     return 1;
 259   if (Minor > GlobalMinor)
 260     return 0;
 261   return Subminor <= GlobalSubminor;
 262 }
 263
 264 static inline uint32_t ConstructVersion(uint32_t Major, uint32_t Minor,
 265                                         uint32_t Subminor) {
 266   return ((Major & 0xffff) << 16) | ((Minor & 0xff) << 8) | (Subminor & 0xff);
 267 }
 268
 269 int32_t __isPlatformVersionAtLeast(uint32_t Platform, uint32_t Major,
 270                                    uint32_t Minor, uint32_t Subminor) {
 271   dispatch_once_f(&DispatchOnceCounter, NULL, initializeAvailabilityCheck);
 272
 273   if (!AvailabilityVersionCheck) {
 274     return __isOSVersionAtLeast(Major, Minor, Subminor);
 275   }
 276   dyld_build_version_t Versions[] = {
 277       {Platform, ConstructVersion(Major, Minor, Subminor)}};
 278   return AvailabilityVersionCheck(1, Versions);
 279 }
 280
 281 #elif __ANDROID__
 282
 283 #include <pthread.h>
 284 #include <stdlib.h>
 285 #include <string.h>
 286 #include <sys/system_properties.h>
 287
 288 static int SdkVersion;
 289 static int IsPreRelease;
 290
 291 static void readSystemProperties(void) {
 292   char buf[PROP_VALUE_MAX];
 293
 294   if (__system_property_get("ro.build.version.sdk", buf) == 0) {
 295     // When the system property doesn't exist, defaults to future API level.
 296     SdkVersion = __ANDROID_API_FUTURE__;
 297   } else {
 298     SdkVersion = atoi(buf);
 299   }
 300
 301   if (__system_property_get("ro.build.version.codename", buf) == 0) {
 302     IsPreRelease = 1;
 303   } else {
 304     IsPreRelease = strcmp(buf, "REL") != 0;
 305   }
 306   return;
 307 }
 308
 309 int32_t __isOSVersionAtLeast(int32_t Major, int32_t Minor, int32_t Subminor) {
 310   (void) Minor;
 311   (void) Subminor;
 312   static pthread_once_t once = PTHREAD_ONCE_INIT;
 313   pthread_once(&once, readSystemProperties);
 314
 315   return SdkVersion >= Major ||
 316          (IsPreRelease && Major == __ANDROID_API_FUTURE__);
 317 }
 318
 319 #else
 320
 321 // Silence an empty translation unit warning.
 322 typedef int unused;
 323
 324 #endif