NativeLauncher/util/utils.cc

   1 /*
   2  * Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the License);
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an AS IS BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <dirent.h>
  18 #include <fcntl.h>
  19 #include <sys/stat.h>
  20 #include <unistd.h>
  21 #include <limits.h>
  22 #include <strings.h>
  23 #include <pkgmgr-info.h>
  24 #include <pkgmgr_installer_info.h>
  25 #include <sys/smack.h>
  26 #include <sys/prctl.h>
  27 #include <openssl/sha.h>
  28
  29 #include <cstdlib>
  30 #include <cstring>
  31 #include <algorithm>
  32 #include <unordered_map>
  33 #include <vector>
  34 #include <iterator>
  35 #include <fstream>
  36 #include <sstream>
  37 #include <map>
  38 #include <iomanip>
  39
  40 #include "log.h"
  41 #include "utils.h"
  42 #include "path_manager.h"
  43
  44 static bool iCompare(const std::string& a, int aOffset, const std::string& b, int bOffset, int length)
  45 {
  46         return static_cast<int>(a.length()) - length >= aOffset &&
  47                 static_cast<int>(b.length()) - length >= bOffset &&
  48                 std::equal(b.begin() + bOffset, b.begin() + bOffset + length, a.begin() + aOffset,
  49                         [](unsigned char a, unsigned char b)
  50                         { return std::tolower(a) == std::tolower(b); });
  51 }
  52
  53 bool isManagedAssembly(const std::string& fileName)
  54 {
  55         return (iCompare(fileName, fileName.size()-4, ".dll", 0, 4) ||
  56                         iCompare(fileName, fileName.size()-4, ".exe", 0, 4)) &&
  57                         !isNativeImage(fileName);
  58 }
  59
  60 bool isNativeImage(const std::string& fileName)
  61 {
  62         return iCompare(fileName, fileName.size()-7, ".ni", 0, 3);
  63 }
  64
  65 std::string concatPath(const std::string& path1, const std::string& path2)
  66 {
  67         std::string path(path1);
  68         if (path.back() == PATH_SEPARATOR) {
  69                 path.append(path2);
  70         } else {
  71                 path += PATH_SEPARATOR;
  72                 path.append(path2);
  73         }
  74
  75         return path;
  76 }
  77
  78 void splitPath(const std::string& path, std::vector<std::string>& out)
  79 {
  80         std::istringstream ss(path);
  81         std::string token;
  82
  83         while (std::getline(ss, token, ':')) {
  84                 out.push_back(token);
  85         }
  86 }
  87
  88 std::string getAbsolutePath(const std::string& path)
  89 {
  90         std::string absPath;
  91         char *realPath = realpath(path.c_str(), NULL);
  92         if (realPath) {
  93                 absPath.assign(realPath);
  94                 free(realPath);
  95         }
  96
  97         return absPath;
  98 }
  99
 100 std::string getRootPath(const std::string& pkgId)
 101 {
 102         int ret = 0;
 103         char *path = 0;
 104         uid_t uid = 0;
 105         std::string rootPath;
 106
 107         if (pkgmgr_installer_info_get_target_uid(&uid) < 0) {
 108                 _ERR("Failed to get UID");
 109                 return rootPath;
 110         }
 111
 112         pkgmgrinfo_pkginfo_h handle;
 113         if (uid == 0) {
 114                 ret = pkgmgrinfo_pkginfo_get_pkginfo(pkgId.c_str(), &handle);
 115                 if (ret != PMINFO_R_OK) {
 116                         return rootPath;
 117                 }
 118         } else {
 119                 ret = pkgmgrinfo_pkginfo_get_usr_pkginfo(pkgId.c_str(), uid, &handle);
 120                 if (ret != PMINFO_R_OK) {
 121                         return rootPath;
 122                 }
 123         }
 124
 125         ret = pkgmgrinfo_pkginfo_get_root_path(handle, &path);
 126         if (ret != PMINFO_R_OK) {
 127                 pkgmgrinfo_pkginfo_destroy_pkginfo(handle);
 128                 return rootPath;
 129         }
 130         rootPath = path;
 131         pkgmgrinfo_pkginfo_destroy_pkginfo(handle);
 132
 133         return rootPath;
 134 }
 135
 136 std::string getExecName(const std::string& pkgId)
 137 {
 138         char *exec = NULL;
 139         char *appId = 0;
 140         std::string execName;
 141
 142         pkgmgrinfo_pkginfo_h pkg_handle;
 143         int ret = pkgmgrinfo_pkginfo_get_pkginfo(pkgId.c_str(), &pkg_handle);
 144         if (ret != PMINFO_R_OK) {
 145                 return execName;
 146         }
 147         ret = pkgmgrinfo_pkginfo_get_mainappid(pkg_handle, &appId);
 148         if (ret != PMINFO_R_OK) {
 149                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 150                 return execName;
 151         }
 152
 153         pkgmgrinfo_appinfo_h app_handle;
 154         ret = pkgmgrinfo_appinfo_get_appinfo(appId, &app_handle);
 155         if (ret != PMINFO_R_OK) {
 156                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 157                 return execName;
 158         }
 159         ret = pkgmgrinfo_appinfo_get_exec(app_handle, &exec);
 160         if (ret != PMINFO_R_OK) {
 161                 pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 162                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 163                 return execName;
 164         }
 165         execName = std::string(exec).substr(std::string(exec).rfind('/') + 1);
 166
 167         pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 168         pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 169
 170         return execName;
 171 }
 172
 173 std::string getAppType(const std::string& pkgId)
 174 {
 175         char *appId = 0;
 176         char *type = 0;
 177         std::string appType;
 178
 179         pkgmgrinfo_pkginfo_h pkg_handle;
 180         int ret = pkgmgrinfo_pkginfo_get_pkginfo(pkgId.c_str(), &pkg_handle);
 181         if (ret != PMINFO_R_OK) {
 182                 return appType;
 183         }
 184         ret = pkgmgrinfo_pkginfo_get_mainappid(pkg_handle, &appId);
 185         if (ret != PMINFO_R_OK) {
 186                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 187                 return appType;
 188         }
 189
 190         pkgmgrinfo_appinfo_h app_handle;
 191         ret = pkgmgrinfo_appinfo_get_appinfo(appId, &app_handle);
 192         if (ret != PMINFO_R_OK) {
 193                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 194                 return appType;
 195         }
 196         ret = pkgmgrinfo_appinfo_get_apptype(app_handle, &type);
 197         if (ret != PMINFO_R_OK) {
 198                 pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 199                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 200                 return appType;
 201         }
 202         appType = type;
 203
 204         pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 205         pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 206
 207         return appType;
 208 }
 209
 210 std::string getMetadataValue(const std::string& pkgId, const std::string& key)
 211 {
 212         char *value = NULL;
 213         char *appId = 0;
 214         std::string metadataValue;
 215
 216         pkgmgrinfo_pkginfo_h pkg_handle;
 217         int ret = pkgmgrinfo_pkginfo_get_pkginfo(pkgId.c_str(), &pkg_handle);
 218         if (ret != PMINFO_R_OK) {
 219                 return metadataValue;
 220         }
 221         ret = pkgmgrinfo_pkginfo_get_mainappid(pkg_handle, &appId);
 222         if (ret != PMINFO_R_OK) {
 223                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 224                 return metadataValue;
 225         }
 226
 227         pkgmgrinfo_appinfo_h app_handle;
 228         ret = pkgmgrinfo_appinfo_get_appinfo(appId, &app_handle);
 229         if (ret != PMINFO_R_OK) {
 230                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 231                 return metadataValue;
 232         }
 233         ret = pkgmgrinfo_appinfo_get_metadata_value(app_handle, key.c_str(), &value);
 234         if (ret != PMINFO_R_OK) {
 235                 pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 236                 pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 237                 return metadataValue;
 238         }
 239         metadataValue = std::string(value);
 240
 241         pkgmgrinfo_appinfo_destroy_appinfo(app_handle);
 242         pkgmgrinfo_pkginfo_destroy_pkginfo(pkg_handle);
 243
 244         return metadataValue;
 245 }
 246
 247 std::string getBaseName(const std::string& path)
 248 {
 249         auto pos = path.find_last_of(PATH_SEPARATOR);
 250         if (pos != std::string::npos)
 251                 return path.substr(0, pos);
 252         else
 253                 return std::string(".");
 254         return path;
 255 }
 256
 257 std::string replaceAll(const std::string& str, const std::string& pattern, const std::string& replace)
 258 {
 259         std::string result = str;
 260         std::string::size_type pos = 0;
 261         std::string::size_type offset = 0;
 262
 263         while ((pos = result.find(pattern, offset)) != std::string::npos) {
 264                 result.replace(result.begin() + pos, result.begin() + pos + pattern.size(), replace);
 265                 offset = pos + replace.size();
 266         }
 267
 268         return result;
 269 }
 270
 271 bool isFile(const std::string& path)
 272 {
 273         struct stat sb;
 274         return lstat(path.c_str(), &sb) == 0;
 275 }
 276
 277 bool isDirectory(const std::string& path)
 278 {
 279         struct stat sb;
 280         if (stat(path.c_str(), &sb) != 0) {
 281                 return false;
 282         }
 283         if (sb.st_mode & S_IFDIR) {
 284                 return true;
 285         } else {
 286                 return false;
 287         }
 288 }
 289
 290 std::string getAssemblyNameFromPath(const std::string& path)
 291 {
 292         std::string ret(getFileName(path));
 293
 294         if (ret.find_last_of(".") == std::string::npos)
 295                 return ret;
 296         ret.erase(ret.find_last_of("."));
 297
 298         if (ret.size() > 3 && std::equal(ret.begin() + ret.size() - 3, ret.end(), ".ni"))
 299                 ret.erase(ret.size() - 3);
 300
 301         return ret;
 302 }
 303
 304 void addAssembliesFromDirectories(const std::vector<std::string>& directories, std::string& list)
 305 {
 306         std::vector<std::string> assems;
 307         std::unordered_map<std::string, std::string> assemPaths;
 308
 309         auto reader = [&assems, &assemPaths](const std::string& path, const std::string& filename) {
 310                 if (isManagedAssembly(filename) || isNativeImage(filename)) {
 311                         std::string assem = getAssemblyNameFromPath(filename);
 312
 313                         if (assemPaths.count(assem) == 0) {
 314                                 assems.push_back(assem);
 315                                 assemPaths[assem] = path;
 316                         } else if (isManagedAssembly(assemPaths[assem]) && isNativeImage(filename)) {
 317                                 // Update only if a native image is found in the same directory.
 318                                 // For example, if we have two directories = { X, Y } where X contains A.dll and
 319                                 // Y contains both A.dll and A.ni.dll, always A.dll in X will be used.
 320                                 if (getBaseName(assemPaths[assem]).compare(getBaseName(path)) == 0)
 321                                         assemPaths[assem] = path;
 322                         }
 323                 }
 324         };
 325         for (auto& directory : directories)
 326                 scanFilesInDirectory(directory, reader, 0);
 327
 328         if (!list.empty() && list.back() != ':')
 329                 list.push_back(':');
 330
 331         for (auto& assem : assems)
 332                 list += assemPaths[assem] + ":";
 333
 334         if (list.back() == ':')
 335                 list.pop_back();
 336 }
 337
 338 void scanFilesInDirectory(const std::string& directory, FileReader reader, unsigned int depth)
 339 {
 340         DIR *dir;
 341         struct dirent* entry;
 342         bool isDir;
 343
 344         dir = opendir(directory.c_str());
 345
 346         if (dir == nullptr)
 347                 return;
 348
 349         std::vector<std::string> innerDirectories;
 350
 351         while ((entry = readdir(dir)) != nullptr) {
 352                 isDir = false;
 353                 std::string path = concatPath(directory, entry->d_name);
 354                 switch (entry->d_type) {
 355                         case DT_REG: break;
 356                         case DT_DIR:
 357                                 isDir = true;
 358                                 break;
 359                         // symlink is added to the list even if there is no original file.
 360                         // It used to remove broken symlinks related to TAC
 361                         case DT_LNK:
 362                                 break;
 363                         case DT_UNKNOWN:
 364                                 continue;
 365                         default:
 366                                 continue;
 367                 }
 368                 if (!isDir)
 369                         reader(path, entry->d_name);
 370                 else if (depth > 0 && strcmp(entry->d_name, ".") && strcmp(entry->d_name, ".."))
 371                         innerDirectories.push_back(path);
 372         }
 373
 374         if (depth > 0)
 375                 for (auto& d : innerDirectories)
 376                         scanFilesInDirectory(d, reader, depth - 1);
 377
 378         closedir(dir);
 379 }
 380
 381 void copySmackAndOwnership(const std::string& fromPath, const std::string& toPath, bool isSymlink)
 382 {
 383         char* label = NULL;
 384         struct stat info;
 385
 386         if (isSymlink) {
 387                 // change smack label for symbolic link.
 388                 if (smack_lgetlabel(fromPath.c_str(), &label, SMACK_LABEL_ACCESS) == 0) {
 389                         if (smack_lsetlabel(toPath.c_str(), label, SMACK_LABEL_ACCESS) < 0) {
 390                                 fprintf(stderr, "Fail to set smack label\n");
 391                         }
 392                         free(label);
 393                 }
 394
 395                 // change owner and groups for symbolic link.
 396                 if (!lstat(fromPath.c_str(), &info)) {
 397                         if (lchown(toPath.c_str(), info.st_uid, info.st_gid) == -1)
 398                                 fprintf(stderr, "Failed to change owner and group name\n");
 399                 }
 400         } else {
 401                 // change smack label
 402                 if (smack_getlabel(fromPath.c_str(), &label, SMACK_LABEL_ACCESS) == 0) {
 403                         if (smack_setlabel(toPath.c_str(), label, SMACK_LABEL_ACCESS) < 0) {
 404                                 fprintf(stderr, "Fail to set smack label\n");
 405                         }
 406                         free(label);
 407                 }
 408
 409                 // change owner and groups for generated ni file.
 410                 if (!stat(fromPath.c_str(), &info)) {
 411                         if (chown(toPath.c_str(), info.st_uid, info.st_gid) == -1)
 412                                 fprintf(stderr, "Failed to change owner and group name\n");
 413                 }
 414         }
 415 }
 416
 417 static bool setOwnership(const bf::path& path, uid_t uid, gid_t gid)
 418 {
 419         int fd = open(path.c_str(), O_RDONLY);
 420         if (fd < 0) {
 421                 _ERR("Can't open directory: %s", path.c_str());
 422                 return false;
 423         }
 424         int ret = fchown(fd, uid, gid);
 425         close(fd);
 426         if (ret != 0) {
 427                 _ERR("Failed to change owner of: %s", path.c_str());
 428                 return false;
 429         }
 430         return true;
 431 }
 432
 433 static bool setDirPermissions(const bf::path& path, bf::perms permissions)
 434 {
 435         bs::error_code error;
 436         bf::permissions(path, permissions, error);
 437         if (error) {
 438                 _ERR("Failed to set permissions for directory: %s, %s", path.c_str(), error.message().c_str());
 439                 return false;
 440         }
 441         return true;
 442 }
 443
 444 static bool setDirOwnershipAndPermissions(const bf::path& path, bf::perms permissions, uid_t uid, gid_t gid)
 445 {
 446         if (!setOwnership(path, uid, gid)) {
 447                 _ERR("Failed to change owner: %s, (uid: %d, gid: %d)", path.c_str(), uid, gid);
 448                 return false;
 449         }
 450         if (!setDirPermissions(path, permissions)) {
 451                 _ERR("Failed to change permission: %s, (%d)", path.c_str(), permissions);
 452                 return false;
 453         }
 454         return true;
 455 }
 456
 457 static bool copyOwnershipAndPermissions(const bf::path& path, const bf::path& path2)
 458 {
 459         if (!bf::exists(path)) {
 460                 _ERR("Failed to copy ownership and permissions from %s to %s", path.c_str(), path2.c_str());
 461                 return false;
 462         }
 463         bf::perms permissions = bf::status(path).permissions();
 464         struct stat stats;
 465         if (stat(path.c_str(), &stats) != 0) {
 466                 return false;
 467         }
 468         if (!setDirOwnershipAndPermissions(path2, permissions, stats.st_uid, stats.st_gid)) {
 469                 _ERR("Failed to copy ownership and permissions from %s to %s", path.c_str(), path2.c_str());
 470                 return false;
 471         }
 472         return true;
 473 }
 474
 475 bool createDir(const bf::path& path)
 476 {
 477         if (bf::exists(path)) {
 478                 return true;
 479         }
 480         bs::error_code error;
 481         bf::create_directories(path, error);
 482         if (error) {
 483                 _ERR("Failed to create directory: %s", error.message().c_str());
 484                 return false;
 485         }
 486         return true;
 487 }
 488
 489 bool copyDir(const bf::path& path1, const bf::path& path2, FSFlag flags)
 490 {
 491         try {
 492                 // Check whether the function call is valid
 493                 if (!bf::exists(path1) || !bf::is_directory(path1)) {
 494                         _ERR("Source directory %s does not exist or is not a directory", path1.c_str());
 495                         return false;
 496                 }
 497                 if (!bf::exists(path2)) {
 498                         // Create the destination directory
 499                         if (!createDir(path2)) {
 500                                 _ERR("Unable to create destination directory %s", path2.c_str());
 501                                 return false;
 502                         }
 503                         if (flags & FS_PRESERVE_OWNERSHIP_AND_PERMISSIONS) {
 504                                 copyOwnershipAndPermissions(path1, path2);
 505                         }
 506                 } else {
 507                         if (!(flags & (FS_MERGE_SKIP | FS_MERGE_OVERWRITE))) {
 508                                 _ERR("Destination directory %s already exists", path2.c_str());
 509                                 return false;
 510                         }
 511                         if (flags & (FS_MERGE_OVERWRITE | FS_PRESERVE_OWNERSHIP_AND_PERMISSIONS)) {
 512                                 copyOwnershipAndPermissions(path1, path2);
 513                         }
 514                 }
 515         } catch (const bf::filesystem_error& error) {
 516                 _ERR("Failed to copy directory: %s", error.what());
 517                 return false;
 518         }
 519
 520         // Iterate through the source directory
 521         for (bf::directory_iterator file(path1); file != bf::directory_iterator(); ++file) {
 522                 try {
 523                         bf::path current(file->path());
 524                         bf::path target = path2 / current.filename();
 525                         if (bf::is_symlink(symlink_status(current))) {
 526                                 if ((flags & (FS_MERGE_SKIP | FS_MERGE_OVERWRITE)) && bf::exists(target)) {
 527                                         continue;
 528                                 }
 529                                 bs::error_code error;
 530                                 bf::copy_symlink(current, target, error);
 531                                 if (error) {
 532                                         _ERR("Failed to copy symlink: %s, %s", current.c_str(), error.message().c_str());
 533                                         return false;
 534                                 }
 535                         } else if (bf::is_directory(current)) {
 536                                 // Found directory: Recursion
 537                                 if (!copyDir(current, target, flags)) {
 538                                         return false;
 539                                 }
 540                         } else {
 541                                 if ((flags & FS_MERGE_SKIP) && bf::exists(target)) {
 542                                         continue;
 543                                 }
 544                                 bf::path destination = target;
 545                                 if (flags & FS_COMMIT_COPY_FILE) {
 546                                         destination = bf::unique_path(target.parent_path() / "%%%%-%%%%-%%%%-%%%%");
 547                                 }
 548                                 if (flags & FS_MERGE_OVERWRITE) {
 549                                         bf::copy_file(current, destination, bf::copy_option::overwrite_if_exists);
 550                                 } else {
 551                                         bf::copy_file(current, destination);
 552                                 }
 553                                 if (flags & FS_PRESERVE_OWNERSHIP_AND_PERMISSIONS) {
 554                                         copyOwnershipAndPermissions(current, destination);
 555                                 }
 556                                 if (flags & FS_COMMIT_COPY_FILE) {
 557                                         if (flags & FS_MERGE_OVERWRITE) {
 558                                                 bf::remove(target);
 559                                         }
 560                                         bf::rename(destination, target);
 561                                 }
 562                         }
 563                 } catch (const bf::filesystem_error& error) {
 564                         _ERR("Failed to copy directory: %s", error.what());
 565                         return false;
 566                 }
 567         }
 568         return true;
 569 }
 570
 571 bool copyFile(const bf::path& path1, const bf::path& path2)
 572 {
 573         bs::error_code error;
 574         if (!bf::exists(path1)) {
 575                 return false;
 576         }
 577         bf::copy_file(path1, path2, bf::copy_option::overwrite_if_exists, error);
 578         if (error) {
 579                 _ERR("copy file %s due to error [%s]", path1.c_str(), error.message().c_str());
 580                 return false;
 581         }
 582         return true;
 583 }
 584
 585 bool moveFile(const bf::path& path1, const bf::path& path2)
 586 {
 587         if (!bf::exists(path1) || bf::exists(path2)) {
 588                 return false;
 589         }
 590         bs::error_code error;
 591         bf::rename(path1, path2, error);
 592         if (error) {
 593                 _ERR("Cannot move file: %s. Will copy/remove... with error [%s]", path1.c_str(), error.message().c_str());
 594                 bf::copy_file(path1, path2, bf::copy_option::overwrite_if_exists, error);
 595                 if (error) {
 596                         _ERR("Cannot copy file %s due to error [%s]", path1.c_str(), error.message().c_str());
 597                         return false;
 598                 }
 599                 bf::remove_all(path1, error);
 600                 if (error) {
 601                         _ERR("Cannot remove old file when coping: %s with error [%s]", path1.c_str(), error.message().c_str());
 602                         return false;
 603                 }
 604         }
 605         return true;
 606 }
 607
 608 bool removeFile(const bf::path& path)
 609 {
 610         if (!bf::exists(path)) {
 611                 return true;
 612         }
 613         bs::error_code error;
 614         bf::remove(path, error);
 615         if (error) {
 616                 _ERR("Cannot remove: %s, %s", path.c_str(), error.message().c_str());
 617                 return false;
 618         }
 619         return true;
 620 }
 621
 622 bool removeAll(const bf::path& path)
 623 {
 624         if (!exists(path)) {
 625                 return true;
 626         }
 627         bs::error_code error;
 628         bf::remove_all(path, error);
 629         if (error) {
 630                 _ERR("Cannot remove: %s, %s", path.c_str(), error.message().c_str());
 631                 return false;
 632         }
 633         return true;
 634 }
 635
 636 void setCmdName(const std::string& name)
 637 {
 638         #define PRC_NAME_LENGTH         16
 639
 640         char processName[PRC_NAME_LENGTH] = {0, };
 641
 642         if (name.empty())
 643                 return;
 644
 645         memset(processName, '\0', PRC_NAME_LENGTH);
 646         snprintf(processName, PRC_NAME_LENGTH, "%s", name.c_str());
 647         prctl(PR_SET_NAME, processName);
 648 }
 649
 650 std::string getFileName(const std::string& path)
 651 {
 652         std::string ret(path);
 653         size_t index = ret.find_last_of(PATH_SEPARATOR);
 654         return index == std::string::npos ? ret : ret.substr(index + 1);
 655 }
 656
 657 std::string SHA256(const std::string& path)
 658 {
 659         std::string output = "";
 660         FILE *file = fopen(path.c_str(), "rb");
 661         if (!file) {
 662                 return output;
 663         }
 664
 665         unsigned char hash[SHA256_DIGEST_LENGTH];
 666         SHA256_CTX sha256;
 667         SHA256_Init(&sha256);
 668         int bytesRead = 0;
 669         const int bufSize = 32768;
 670         char *buffer = (char*)malloc(bufSize);
 671         if (!buffer) {
 672                 fclose(file);
 673                 return output;
 674         }
 675
 676         while ((bytesRead = fread(buffer, 1, bufSize, file))) {
 677                 SHA256_Update(&sha256, buffer, bytesRead);
 678         }
 679         SHA256_Final(hash, &sha256);
 680
 681         std::stringstream ss;
 682         for (int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
 683                 ss << std::hex << std::setw(2) << std::setfill('0') << (int)hash[i];
 684         }
 685         output = ss.str();
 686
 687         fclose(file);
 688         free(buffer);
 689
 690         return output;
 691 }