src/porting.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 /*
  21         Random portability stuff
  22
  23         See comments in porting.h
  24 */
  25
  26 #include "porting.h"
  27
  28 #if defined(__FreeBSD__)  || defined(__NetBSD__) || defined(__DragonFly__)
  29         #include <sys/types.h>
  30         #include <sys/sysctl.h>
  31         extern char **environ;
  32 #elif defined(_WIN32)
  33         #include <windows.h>
  34         #include <wincrypt.h>
  35         #include <algorithm>
  36         #include <shlwapi.h>
  37         #include <shellapi.h>
  38 #endif
  39 #if !defined(_WIN32)
  40         #include <unistd.h>
  41         #include <sys/utsname.h>
  42         #if !defined(__ANDROID__)
  43                 #include <spawn.h>
  44         #endif
  45 #endif
  46 #if defined(__hpux)
  47         #define _PSTAT64
  48         #include <sys/pstat.h>
  49 #endif
  50 #if defined(__ANDROID__)
  51         #include "porting_android.h"
  52 #endif
  53 #if defined(__APPLE__)
  54         // For _NSGetEnviron()
  55         // Related: https://gitlab.haskell.org/ghc/ghc/issues/2458
  56         #include <crt_externs.h>
  57 #endif
  58
  59 #include "config.h"
  60 #include "debug.h"
  61 #include "filesys.h"
  62 #include "log.h"
  63 #include "util/string.h"
  64 #include <list>
  65 #include <cstdarg>
  66 #include <cstdio>
  67
  68 namespace porting
  69 {
  70
  71 /*
  72         Signal handler (grabs Ctrl-C on POSIX systems)
  73 */
  74
  75 bool g_killed = false;
  76
  77 bool *signal_handler_killstatus()
  78 {
  79         return &g_killed;
  80 }
  81
  82 #if !defined(_WIN32) // POSIX
  83         #include <signal.h>
  84
  85 void signal_handler(int sig)
  86 {
  87         if (!g_killed) {
  88                 if (sig == SIGINT) {
  89                         dstream << "INFO: signal_handler(): "
  90                                 << "Ctrl-C pressed, shutting down." << std::endl;
  91                 } else if (sig == SIGTERM) {
  92                         dstream << "INFO: signal_handler(): "
  93                                 << "got SIGTERM, shutting down." << std::endl;
  94                 }
  95
  96                 // Comment out for less clutter when testing scripts
  97                 /*dstream << "INFO: sigint_handler(): "
  98                                 << "Printing debug stacks" << std::endl;
  99                 debug_stacks_print();*/
 100
 101                 g_killed = true;
 102         } else {
 103                 (void)signal(sig, SIG_DFL);
 104         }
 105 }
 106
 107 void signal_handler_init(void)
 108 {
 109         (void)signal(SIGINT, signal_handler);
 110         (void)signal(SIGTERM, signal_handler);
 111 }
 112
 113 #else // _WIN32
 114         #include <signal.h>
 115
 116 BOOL WINAPI event_handler(DWORD sig)
 117 {
 118         switch (sig) {
 119         case CTRL_C_EVENT:
 120         case CTRL_CLOSE_EVENT:
 121         case CTRL_LOGOFF_EVENT:
 122         case CTRL_SHUTDOWN_EVENT:
 123                 if (!g_killed) {
 124                         dstream << "INFO: event_handler(): "
 125                                 << "Ctrl+C, Close Event, Logoff Event or Shutdown Event,"
 126                                 " shutting down." << std::endl;
 127                         g_killed = true;
 128                 } else {
 129                         (void)signal(SIGINT, SIG_DFL);
 130                 }
 131                 break;
 132         case CTRL_BREAK_EVENT:
 133                 break;
 134         }
 135
 136         return TRUE;
 137 }
 138
 139 void signal_handler_init(void)
 140 {
 141         SetConsoleCtrlHandler((PHANDLER_ROUTINE)event_handler, TRUE);
 142 }
 143
 144 #endif
 145
 146
 147 /*
 148         Path mangler
 149 */
 150
 151 // Default to RUN_IN_PLACE style relative paths
 152 std::string path_share = "..";
 153 std::string path_user = "..";
 154 std::string path_locale = path_share + DIR_DELIM + "locale";
 155 std::string path_cache = path_user + DIR_DELIM + "cache";
 156
 157
 158 std::string getDataPath(const char *subpath)
 159 {
 160         return path_share + DIR_DELIM + subpath;
 161 }
 162
 163 void pathRemoveFile(char *path, char delim)
 164 {
 165         // Remove filename and path delimiter
 166         int i;
 167         for(i = strlen(path)-1; i>=0; i--)
 168         {
 169                 if(path[i] == delim)
 170                         break;
 171         }
 172         path[i] = 0;
 173 }
 174
 175 bool detectMSVCBuildDir(const std::string &path)
 176 {
 177         const char *ends[] = {
 178                 "bin\\Release",
 179                 "bin\\MinSizeRel",
 180                 "bin\\RelWithDebInfo",
 181                 "bin\\Debug",
 182                 "bin\\Build",
 183                 NULL
 184         };
 185         return (!removeStringEnd(path, ends).empty());
 186 }
 187
 188 std::string get_sysinfo()
 189 {
 190 #ifdef _WIN32
 191
 192         std::ostringstream oss;
 193         LPSTR filePath = new char[MAX_PATH];
 194         UINT blockSize;
 195         VS_FIXEDFILEINFO *fixedFileInfo;
 196
 197         GetSystemDirectoryA(filePath, MAX_PATH);
 198         PathAppendA(filePath, "kernel32.dll");
 199
 200         DWORD dwVersionSize = GetFileVersionInfoSizeA(filePath, NULL);
 201         LPBYTE lpVersionInfo = new BYTE[dwVersionSize];
 202
 203         GetFileVersionInfoA(filePath, 0, dwVersionSize, lpVersionInfo);
 204         VerQueryValueA(lpVersionInfo, "\\", (LPVOID *)&fixedFileInfo, &blockSize);
 205
 206         oss << "Windows/"
 207                 << HIWORD(fixedFileInfo->dwProductVersionMS) << '.' // Major
 208                 << LOWORD(fixedFileInfo->dwProductVersionMS) << '.' // Minor
 209                 << HIWORD(fixedFileInfo->dwProductVersionLS) << ' '; // Build
 210
 211         #ifdef _WIN64
 212         oss << "x86_64";
 213         #else
 214         BOOL is64 = FALSE;
 215         if (IsWow64Process(GetCurrentProcess(), &is64) && is64)
 216                 oss << "x86_64"; // 32-bit app on 64-bit OS
 217         else
 218                 oss << "x86";
 219         #endif
 220
 221         delete[] lpVersionInfo;
 222         delete[] filePath;
 223
 224         return oss.str();
 225 #else
 226         struct utsname osinfo;
 227         uname(&osinfo);
 228         return std::string(osinfo.sysname) + "/"
 229                 + osinfo.release + " " + osinfo.machine;
 230 #endif
 231 }
 232
 233
 234 bool getCurrentWorkingDir(char *buf, size_t len)
 235 {
 236 #ifdef _WIN32
 237         DWORD ret = GetCurrentDirectory(len, buf);
 238         return (ret != 0) && (ret <= len);
 239 #else
 240         return getcwd(buf, len);
 241 #endif
 242 }
 243
 244
 245 bool getExecPathFromProcfs(char *buf, size_t buflen)
 246 {
 247 #ifndef _WIN32
 248         buflen--;
 249
 250         ssize_t len;
 251         if ((len = readlink("/proc/self/exe",     buf, buflen)) == -1 &&
 252                 (len = readlink("/proc/curproc/file", buf, buflen)) == -1 &&
 253                 (len = readlink("/proc/curproc/exe",  buf, buflen)) == -1)
 254                 return false;
 255
 256         buf[len] = '\0';
 257         return true;
 258 #else
 259         return false;
 260 #endif
 261 }
 262
 263 //// Windows
 264 #if defined(_WIN32)
 265
 266 bool getCurrentExecPath(char *buf, size_t len)
 267 {
 268         DWORD written = GetModuleFileNameA(NULL, buf, len);
 269         if (written == 0 || written == len)
 270                 return false;
 271
 272         return true;
 273 }
 274
 275
 276 //// Linux
 277 #elif defined(__linux__)
 278
 279 bool getCurrentExecPath(char *buf, size_t len)
 280 {
 281         if (!getExecPathFromProcfs(buf, len))
 282                 return false;
 283
 284         return true;
 285 }
 286
 287
 288 //// Mac OS X, Darwin
 289 #elif defined(__APPLE__)
 290
 291 bool getCurrentExecPath(char *buf, size_t len)
 292 {
 293         uint32_t lenb = (uint32_t)len;
 294         if (_NSGetExecutablePath(buf, &lenb) == -1)
 295                 return false;
 296
 297         return true;
 298 }
 299
 300
 301 //// FreeBSD, NetBSD, DragonFlyBSD
 302 #elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
 303
 304 bool getCurrentExecPath(char *buf, size_t len)
 305 {
 306         // Try getting path from procfs first, since valgrind
 307         // doesn't work with the latter
 308         if (getExecPathFromProcfs(buf, len))
 309                 return true;
 310
 311         int mib[4];
 312
 313         mib[0] = CTL_KERN;
 314         mib[1] = KERN_PROC;
 315         mib[2] = KERN_PROC_PATHNAME;
 316         mib[3] = -1;
 317
 318         if (sysctl(mib, 4, buf, &len, NULL, 0) == -1)
 319                 return false;
 320
 321         return true;
 322 }
 323
 324
 325 //// Solaris
 326 #elif defined(__sun) || defined(sun)
 327
 328 bool getCurrentExecPath(char *buf, size_t len)
 329 {
 330         const char *exec = getexecname();
 331         if (exec == NULL)
 332                 return false;
 333
 334         if (strlcpy(buf, exec, len) >= len)
 335                 return false;
 336
 337         return true;
 338 }
 339
 340
 341 // HP-UX
 342 #elif defined(__hpux)
 343
 344 bool getCurrentExecPath(char *buf, size_t len)
 345 {
 346         struct pst_status psts;
 347
 348         if (pstat_getproc(&psts, sizeof(psts), 0, getpid()) == -1)
 349                 return false;
 350
 351         if (pstat_getpathname(buf, len, &psts.pst_fid_text) == -1)
 352                 return false;
 353
 354         return true;
 355 }
 356
 357
 358 #else
 359
 360 bool getCurrentExecPath(char *buf, size_t len)
 361 {
 362         return false;
 363 }
 364
 365 #endif
 366
 367
 368 //// Non-Windows
 369 #if !defined(_WIN32)
 370
 371 const char *getHomeOrFail()
 372 {
 373         const char *home = getenv("HOME");
 374         // In rare cases the HOME environment variable may be unset
 375         FATAL_ERROR_IF(!home,
 376                 "Required environment variable HOME is not set");
 377         return home;
 378 }
 379
 380 #endif
 381
 382
 383 //// Windows
 384 #if defined(_WIN32)
 385
 386 bool setSystemPaths()
 387 {
 388         char buf[BUFSIZ];
 389
 390         // Find path of executable and set path_share relative to it
 391         FATAL_ERROR_IF(!getCurrentExecPath(buf, sizeof(buf)),
 392                 "Failed to get current executable path");
 393         pathRemoveFile(buf, '\\');
 394
 395         std::string exepath(buf);
 396
 397         // Use ".\bin\.."
 398         path_share = exepath + "\\..";
 399         if (detectMSVCBuildDir(exepath)) {
 400                 // The msvc build dir schould normaly not be present if properly installed,
 401                 // but its usefull for debugging.
 402                 path_share += DIR_DELIM "..";
 403         }
 404
 405         // Use "C:\Users\<user>\AppData\Roaming\<PROJECT_NAME_C>"
 406         DWORD len = GetEnvironmentVariable("APPDATA", buf, sizeof(buf));
 407         FATAL_ERROR_IF(len == 0 || len > sizeof(buf), "Failed to get APPDATA");
 408
 409         path_user = std::string(buf) + DIR_DELIM + PROJECT_NAME_C;
 410         return true;
 411 }
 412
 413
 414 //// Linux
 415 #elif defined(__linux__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
 416
 417 bool setSystemPaths()
 418 {
 419         char buf[BUFSIZ];
 420
 421         if (!getCurrentExecPath(buf, sizeof(buf))) {
 422 #ifdef __ANDROID__
 423                 errorstream << "Unable to read bindir "<< std::endl;
 424 #else
 425                 FATAL_ERROR("Unable to read bindir");
 426 #endif
 427                 return false;
 428         }
 429
 430         pathRemoveFile(buf, '/');
 431         std::string bindir(buf);
 432
 433         // Find share directory from these.
 434         // It is identified by containing the subdirectory "builtin".
 435         std::list<std::string> trylist;
 436         std::string static_sharedir = STATIC_SHAREDIR;
 437         if (!static_sharedir.empty() && static_sharedir != ".")
 438                 trylist.push_back(static_sharedir);
 439
 440         trylist.push_back(bindir + DIR_DELIM ".." DIR_DELIM "share"
 441                 DIR_DELIM + PROJECT_NAME);
 442         trylist.push_back(bindir + DIR_DELIM "..");
 443
 444 #ifdef __ANDROID__
 445         trylist.push_back(path_user);
 446 #endif
 447
 448         for (std::list<std::string>::const_iterator
 449                         i = trylist.begin(); i != trylist.end(); ++i) {
 450                 const std::string &trypath = *i;
 451                 if (!fs::PathExists(trypath) ||
 452                         !fs::PathExists(trypath + DIR_DELIM + "builtin")) {
 453                         warningstream << "system-wide share not found at \""
 454                                         << trypath << "\""<< std::endl;
 455                         continue;
 456                 }
 457
 458                 // Warn if was not the first alternative
 459                 if (i != trylist.begin()) {
 460                         warningstream << "system-wide share found at \""
 461                                         << trypath << "\"" << std::endl;
 462                 }
 463
 464                 path_share = trypath;
 465                 break;
 466         }
 467
 468 #ifndef __ANDROID__
 469         path_user = std::string(getHomeOrFail()) + DIR_DELIM "."
 470                 + PROJECT_NAME;
 471 #endif
 472
 473         return true;
 474 }
 475
 476
 477 //// Mac OS X
 478 #elif defined(__APPLE__)
 479
 480 bool setSystemPaths()
 481 {
 482         CFBundleRef main_bundle = CFBundleGetMainBundle();
 483         CFURLRef resources_url = CFBundleCopyResourcesDirectoryURL(main_bundle);
 484         char path[PATH_MAX];
 485         if (CFURLGetFileSystemRepresentation(resources_url,
 486                         TRUE, (UInt8 *)path, PATH_MAX)) {
 487                 path_share = std::string(path);
 488         } else {
 489                 warningstream << "Could not determine bundle resource path" << std::endl;
 490         }
 491         CFRelease(resources_url);
 492
 493         path_user = std::string(getHomeOrFail())
 494                 + "/Library/Application Support/"
 495                 + PROJECT_NAME;
 496         return true;
 497 }
 498
 499
 500 #else
 501
 502 bool setSystemPaths()
 503 {
 504         path_share = STATIC_SHAREDIR;
 505         path_user  = std::string(getHomeOrFail()) + DIR_DELIM "."
 506                 + lowercase(PROJECT_NAME);
 507         return true;
 508 }
 509
 510
 511 #endif
 512
 513 void migrateCachePath()
 514 {
 515         const std::string local_cache_path = path_user + DIR_DELIM + "cache";
 516
 517         // Delete tmp folder if it exists (it only ever contained
 518         // a temporary ogg file, which is no longer used).
 519         if (fs::PathExists(local_cache_path + DIR_DELIM + "tmp"))
 520                 fs::RecursiveDelete(local_cache_path + DIR_DELIM + "tmp");
 521
 522         // Bail if migration impossible
 523         if (path_cache == local_cache_path || !fs::PathExists(local_cache_path)
 524                         || fs::PathExists(path_cache)) {
 525                 return;
 526         }
 527         if (!fs::Rename(local_cache_path, path_cache)) {
 528                 errorstream << "Failed to migrate local cache path "
 529                         "to system path!" << std::endl;
 530         }
 531 }
 532
 533 void initializePaths()
 534 {
 535 #if RUN_IN_PLACE
 536         char buf[BUFSIZ];
 537
 538         infostream << "Using relative paths (RUN_IN_PLACE)" << std::endl;
 539
 540         bool success =
 541                 getCurrentExecPath(buf, sizeof(buf)) ||
 542                 getExecPathFromProcfs(buf, sizeof(buf));
 543
 544         if (success) {
 545                 pathRemoveFile(buf, DIR_DELIM_CHAR);
 546                 std::string execpath(buf);
 547
 548                 path_share = execpath + DIR_DELIM "..";
 549                 path_user  = execpath + DIR_DELIM "..";
 550
 551                 if (detectMSVCBuildDir(execpath)) {
 552                         path_share += DIR_DELIM "..";
 553                         path_user  += DIR_DELIM "..";
 554                 }
 555         } else {
 556                 errorstream << "Failed to get paths by executable location, "
 557                         "trying cwd" << std::endl;
 558
 559                 if (!getCurrentWorkingDir(buf, sizeof(buf)))
 560                         FATAL_ERROR("Ran out of methods to get paths");
 561
 562                 size_t cwdlen = strlen(buf);
 563                 if (cwdlen >= 1 && buf[cwdlen - 1] == DIR_DELIM_CHAR) {
 564                         cwdlen--;
 565                         buf[cwdlen] = '\0';
 566                 }
 567
 568                 if (cwdlen >= 4 && !strcmp(buf + cwdlen - 4, DIR_DELIM "bin"))
 569                         pathRemoveFile(buf, DIR_DELIM_CHAR);
 570
 571                 std::string execpath(buf);
 572
 573                 path_share = execpath;
 574                 path_user  = execpath;
 575         }
 576         path_cache = path_user + DIR_DELIM + "cache";
 577 #else
 578         infostream << "Using system-wide paths (NOT RUN_IN_PLACE)" << std::endl;
 579
 580         if (!setSystemPaths())
 581                 errorstream << "Failed to get one or more system-wide path" << std::endl;
 582
 583
 584 #  ifdef _WIN32
 585         path_cache = path_user + DIR_DELIM + "cache";
 586 #  else
 587         // Initialize path_cache
 588         // First try $XDG_CACHE_HOME/PROJECT_NAME
 589         const char *cache_dir = getenv("XDG_CACHE_HOME");
 590         const char *home_dir = getenv("HOME");
 591         if (cache_dir) {
 592                 path_cache = std::string(cache_dir) + DIR_DELIM + PROJECT_NAME;
 593         } else if (home_dir) {
 594                 // Then try $HOME/.cache/PROJECT_NAME
 595                 path_cache = std::string(home_dir) + DIR_DELIM + ".cache"
 596                         + DIR_DELIM + PROJECT_NAME;
 597         } else {
 598                 // If neither works, use $PATH_USER/cache
 599                 path_cache = path_user + DIR_DELIM + "cache";
 600         }
 601         // Migrate cache folder to new location if possible
 602         migrateCachePath();
 603 #  endif // _WIN32
 604 #endif // RUN_IN_PLACE
 605
 606         infostream << "Detected share path: " << path_share << std::endl;
 607         infostream << "Detected user path: " << path_user << std::endl;
 608         infostream << "Detected cache path: " << path_cache << std::endl;
 609
 610 #if USE_GETTEXT
 611         bool found_localedir = false;
 612 #  ifdef STATIC_LOCALEDIR
 613         /* STATIC_LOCALEDIR may be a generalized path such as /usr/share/locale that
 614          * doesn't necessarily contain our locale files, so check data path first. */
 615         path_locale = getDataPath("locale");
 616         if (fs::PathExists(path_locale)) {
 617                 found_localedir = true;
 618                 infostream << "Using in-place locale directory " << path_locale
 619                         << " even though a static one was provided." << std::endl;
 620         } else if (STATIC_LOCALEDIR[0] && fs::PathExists(STATIC_LOCALEDIR)) {
 621                 found_localedir = true;
 622                 path_locale = STATIC_LOCALEDIR;
 623                 infostream << "Using static locale directory " << STATIC_LOCALEDIR
 624                         << std::endl;
 625         }
 626 #  else
 627         path_locale = getDataPath("locale");
 628         if (fs::PathExists(path_locale)) {
 629                 found_localedir = true;
 630         }
 631 #  endif
 632         if (!found_localedir) {
 633                 warningstream << "Couldn't find a locale directory!" << std::endl;
 634         }
 635 #endif  // USE_GETTEXT
 636 }
 637
 638 ////
 639 //// OS-specific Secure Random
 640 ////
 641
 642 #ifdef WIN32
 643
 644 bool secure_rand_fill_buf(void *buf, size_t len)
 645 {
 646         HCRYPTPROV wctx;
 647
 648         if (!CryptAcquireContext(&wctx, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
 649                 return false;
 650
 651         CryptGenRandom(wctx, len, (BYTE *)buf);
 652         CryptReleaseContext(wctx, 0);
 653         return true;
 654 }
 655
 656 #else
 657
 658 bool secure_rand_fill_buf(void *buf, size_t len)
 659 {
 660         // N.B.  This function checks *only* for /dev/urandom, because on most
 661         // common OSes it is non-blocking, whereas /dev/random is blocking, and it
 662         // is exceptionally uncommon for there to be a situation where /dev/random
 663         // exists but /dev/urandom does not.  This guesswork is necessary since
 664         // random devices are not covered by any POSIX standard...
 665         FILE *fp = fopen("/dev/urandom", "rb");
 666         if (!fp)
 667                 return false;
 668
 669         bool success = fread(buf, len, 1, fp) == 1;
 670
 671         fclose(fp);
 672         return success;
 673 }
 674
 675 #endif
 676
 677 void attachOrCreateConsole()
 678 {
 679 #ifdef _WIN32
 680         static bool consoleAllocated = false;
 681         const bool redirected = (_fileno(stdout) == -2 || _fileno(stdout) == -1); // If output is redirected to e.g a file
 682         if (!consoleAllocated && redirected && (AttachConsole(ATTACH_PARENT_PROCESS) || AllocConsole())) {
 683                 freopen("CONOUT$", "w", stdout);
 684                 freopen("CONOUT$", "w", stderr);
 685                 consoleAllocated = true;
 686         }
 687 #endif
 688 }
 689
 690 int mt_snprintf(char *buf, const size_t buf_size, const char *fmt, ...)
 691 {
 692         // https://msdn.microsoft.com/en-us/library/bt7tawza.aspx
 693         //  Many of the MSVC / Windows printf-style functions do not support positional
 694         //  arguments (eg. "%1$s"). We just forward the call to vsnprintf for sane
 695         //  platforms, but defer to _vsprintf_p on MSVC / Windows.
 696         // https://github.com/FFmpeg/FFmpeg/blob/5ae9fa13f5ac640bec113120d540f70971aa635d/compat/msvcrt/snprintf.c#L46
 697         //  _vsprintf_p has to be shimmed with _vscprintf_p on -1 (for an example see
 698         //  above FFmpeg link).
 699         va_list args;
 700         va_start(args, fmt);
 701 #ifndef _MSC_VER
 702         int c = vsnprintf(buf, buf_size, fmt, args);
 703 #else  // _MSC_VER
 704         int c = _vsprintf_p(buf, buf_size, fmt, args);
 705         if (c == -1)
 706                 c = _vscprintf_p(fmt, args);
 707 #endif // _MSC_VER
 708         va_end(args);
 709         return c;
 710 }
 711
 712 bool openURL(const std::string &url)
 713 {
 714         if ((url.substr(0, 7) != "http://" && url.substr(0, 8) != "https://") ||
 715                         url.find_first_of("\r\n") != std::string::npos) {
 716                 errorstream << "Invalid url: " << url << std::endl;
 717                 return false;
 718         }
 719
 720 #if defined(_WIN32)
 721         return (intptr_t)ShellExecuteA(NULL, NULL, url.c_str(), NULL, NULL, SW_SHOWNORMAL) > 32;
 722 #elif defined(__ANDROID__)
 723         openURLAndroid(url);
 724         return true;
 725 #elif defined(__APPLE__)
 726         const char *argv[] = {"open", url.c_str(), NULL};
 727         return posix_spawnp(NULL, "open", NULL, NULL, (char**)argv,
 728                 (*_NSGetEnviron())) == 0;
 729 #else
 730         const char *argv[] = {"xdg-open", url.c_str(), NULL};
 731         return posix_spawnp(NULL, "xdg-open", NULL, NULL, (char**)argv, environ) == 0;
 732 #endif
 733 }
 734
 735 // Load performance counter frequency only once at startup
 736 #ifdef _WIN32
 737
 738 inline double get_perf_freq()
 739 {
 740         LARGE_INTEGER freq;
 741         QueryPerformanceFrequency(&freq);
 742         return freq.QuadPart;
 743 }
 744
 745 double perf_freq = get_perf_freq();
 746
 747 #endif
 748
 749 } //namespace porting