components/nacl/renderer/json_manifest.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/nacl/renderer/json_manifest.h"
   6
   7 #include <set>
   8
   9 #include "base/logging.h"
  10 #include "base/macros.h"
  11 #include "components/nacl/renderer/nexe_load_manager.h"
  12 #include "third_party/jsoncpp/source/include/json/reader.h"
  13 #include "third_party/jsoncpp/source/include/json/value.h"
  14 #include "url/gurl.h"
  15
  16 namespace nacl {
  17
  18 namespace {
  19 // Top-level section name keys
  20 const char* const kProgramKey =     "program";
  21 const char* const kInterpreterKey = "interpreter";
  22 const char* const kFilesKey =       "files";
  23
  24 // ISA Dictionary keys
  25 const char* const kX8632Key =       "x86-32";
  26 const char* const kX8632NonSFIKey = "x86-32-nonsfi";
  27 const char* const kX8664Key =       "x86-64";
  28 const char* const kX8664NonSFIKey = "x86-64-nonsfi";
  29 const char* const kArmKey =         "arm";
  30 const char* const kArmNonSFIKey =   "arm-nonsfi";
  31 const char* const kPortableKey =    "portable";
  32
  33 // Url Resolution keys
  34 const char* const kPnaclDebugKey =     "pnacl-debug";
  35 const char* const kPnaclTranslateKey = "pnacl-translate";
  36 const char* const kUrlKey =            "url";
  37
  38 // PNaCl keys
  39 const char* const kOptLevelKey = "optlevel";
  40
  41 // Sample NaCl manifest file:
  42 // {
  43 //   "program": {
  44 //     "x86-32": {"url": "myprogram_x86-32.nexe"},
  45 //     "x86-64": {"url": "myprogram_x86-64.nexe"},
  46 //     "arm": {"url": "myprogram_arm.nexe"}
  47 //   },
  48 //   "interpreter": {
  49 //     "x86-32": {"url": "interpreter_x86-32.nexe"},
  50 //     "x86-64": {"url": "interpreter_x86-64.nexe"},
  51 //     "arm": {"url": "interpreter_arm.nexe"}
  52 //   },
  53 //   "files": {
  54 //     "foo.txt": {
  55 //       "portable": {"url": "foo.txt"}
  56 //     },
  57 //     "bar.txt": {
  58 //       "x86-32": {"url": "x86-32/bar.txt"},
  59 //       "portable": {"url": "bar.txt"}
  60 //     },
  61 //     "libfoo.so": {
  62 //       "x86-64" : { "url": "..." }
  63 //     }
  64 //   }
  65 // }
  66
  67 // Sample PNaCl manifest file:
  68 // {
  69 //   "program": {
  70 //     "portable": {
  71 //       "pnacl-translate": {
  72 //         "url": "myprogram.pexe"
  73 //       },
  74 //       "pnacl-debug": {
  75 //         "url": "myprogram.debug.pexe",
  76 //         "opt_level": 0
  77 //       }
  78 //     }
  79 //   },
  80 //   "files": {
  81 //     "foo.txt": {
  82 //       "portable": {"url": "foo.txt"}
  83 //     },
  84 //     "bar.txt": {
  85 //       "portable": {"url": "bar.txt"}
  86 //     }
  87 //   }
  88 // }
  89
  90 // Returns the key for the architecture in non-SFI mode.
  91 std::string GetNonSFIKey(const std::string& sandbox_isa) {
  92   return sandbox_isa + "-nonsfi";
  93 }
  94
  95 // Looks up |property_name| in the vector |valid_names| with length
  96 // |valid_name_count|.  Returns true if |property_name| is found.
  97 bool FindMatchingProperty(const std::string& property_name,
  98                           const char** valid_names,
  99                           size_t valid_name_count) {
 100   for (size_t i = 0; i < valid_name_count; ++i) {
 101     if (property_name == valid_names[i]) {
 102       return true;
 103     }
 104   }
 105   return false;
 106 }
 107
 108 // Return true if this is a valid dictionary.  Having only keys present in
 109 // |valid_keys| and having at least the keys in |required_keys|.
 110 // Error messages will be placed in |error_string|, given that the dictionary
 111 // was the property value of |container_key|.
 112 // E.g., "container_key" : dictionary
 113 bool IsValidDictionary(const Json::Value& dictionary,
 114                        const std::string& container_key,
 115                        const std::string& parent_key,
 116                        const char** valid_keys,
 117                        size_t valid_key_count,
 118                        const char** required_keys,
 119                        size_t required_key_count,
 120                        std::string* error_string) {
 121   if (!dictionary.isObject()) {
 122     std::stringstream error_stream;
 123     error_stream << parent_key << " property '" << container_key
 124                  << "' is non-dictionary value '"
 125                  << dictionary.toStyledString() << "'.";
 126     *error_string = error_stream.str();
 127     return false;
 128   }
 129   // Check for unknown dictionary members.
 130   Json::Value::Members members = dictionary.getMemberNames();
 131   for (size_t i = 0; i < members.size(); ++i) {
 132     std::string property_name = members[i];
 133     if (!FindMatchingProperty(property_name,
 134                               valid_keys,
 135                               valid_key_count)) {
 136       // For forward compatibility, we do not prohibit other keys being in
 137       // the dictionary.
 138       VLOG(1) << "WARNING: '" << parent_key << "' property '"
 139               << container_key << "' has unknown key '"
 140               << property_name << "'.";
 141     }
 142   }
 143   // Check for required members.
 144   for (size_t i = 0; i < required_key_count; ++i) {
 145     if (!dictionary.isMember(required_keys[i])) {
 146       std::stringstream error_stream;
 147       error_stream << parent_key << " property '" << container_key
 148                    << "' does not have required key: '"
 149                    << required_keys[i] << "'.";
 150       *error_string = error_stream.str();
 151       return false;
 152     }
 153   }
 154   return true;
 155 }
 156
 157 // Validate a "url" dictionary assuming it was resolved from container_key.
 158 // E.g., "container_key" : { "url": "foo.txt" }
 159 bool IsValidUrlSpec(const Json::Value& url_spec,
 160                     const std::string& container_key,
 161                     const std::string& parent_key,
 162                     const std::string& sandbox_isa,
 163                     std::string* error_string) {
 164   static const char* kManifestUrlSpecRequired[] = {
 165     kUrlKey
 166   };
 167   const char** urlSpecPlusOptional;
 168   size_t urlSpecPlusOptionalLength;
 169   if (sandbox_isa == kPortableKey) {
 170     static const char* kPnaclUrlSpecPlusOptional[] = {
 171       kUrlKey,
 172       kOptLevelKey,
 173     };
 174     urlSpecPlusOptional = kPnaclUrlSpecPlusOptional;
 175     urlSpecPlusOptionalLength = arraysize(kPnaclUrlSpecPlusOptional);
 176   } else {
 177     // URL specifications must not contain "pnacl-translate" keys.
 178     // This prohibits NaCl clients from invoking PNaCl.
 179     if (url_spec.isMember(kPnaclTranslateKey)) {
 180       std::stringstream error_stream;
 181       error_stream << "PNaCl-like NMF with application/x-nacl mimetype instead "
 182                    << "of x-pnacl mimetype (has " << kPnaclTranslateKey << ").";
 183       *error_string = error_stream.str();
 184       return false;
 185     }
 186     urlSpecPlusOptional = kManifestUrlSpecRequired;
 187     urlSpecPlusOptionalLength = arraysize(kManifestUrlSpecRequired);
 188   }
 189   if (!IsValidDictionary(url_spec, container_key, parent_key,
 190                          urlSpecPlusOptional,
 191                          urlSpecPlusOptionalLength,
 192                          kManifestUrlSpecRequired,
 193                          arraysize(kManifestUrlSpecRequired),
 194                          error_string)) {
 195     return false;
 196   }
 197   // Verify the correct types of the fields if they exist.
 198   Json::Value url = url_spec[kUrlKey];
 199   if (!url.isString()) {
 200     std::stringstream error_stream;
 201     error_stream << parent_key << " property '" << container_key <<
 202         "' has non-string value '" << url.toStyledString() <<
 203         "' for key '" << kUrlKey << "'.";
 204     *error_string = error_stream.str();
 205     return false;
 206   }
 207   Json::Value opt_level = url_spec[kOptLevelKey];
 208   if (!opt_level.empty() && !opt_level.isNumeric()) {
 209     std::stringstream error_stream;
 210     error_stream << parent_key << " property '" << container_key <<
 211         "' has non-numeric value '" << opt_level.toStyledString() <<
 212         "' for key '" << kOptLevelKey << "'.";
 213     *error_string = error_stream.str();
 214     return false;
 215   }
 216   return true;
 217 }
 218
 219 // Validate a "pnacl-translate" or "pnacl-debug" dictionary, assuming
 220 // it was resolved from container_key.
 221 // E.g., "container_key" : { "pnacl-translate" : URLSpec }
 222 bool IsValidPnaclTranslateSpec(const Json::Value& pnacl_spec,
 223                                const std::string& container_key,
 224                                const std::string& parent_key,
 225                                const std::string& sandbox_isa,
 226                                std::string* error_string) {
 227   static const char* kManifestPnaclSpecValid[] = {
 228     kPnaclDebugKey,
 229     kPnaclTranslateKey
 230   };
 231   static const char* kManifestPnaclSpecRequired[] = { kPnaclTranslateKey };
 232   if (!IsValidDictionary(pnacl_spec, container_key, parent_key,
 233                          kManifestPnaclSpecValid,
 234                          arraysize(kManifestPnaclSpecValid),
 235                          kManifestPnaclSpecRequired,
 236                          arraysize(kManifestPnaclSpecRequired),
 237                          error_string)) {
 238     return false;
 239   }
 240   Json::Value url_spec = pnacl_spec[kPnaclTranslateKey];
 241   return IsValidUrlSpec(url_spec, kPnaclTranslateKey,
 242                         container_key, sandbox_isa, error_string);
 243 }
 244
 245 // Validates that |dictionary| is a valid ISA dictionary.  An ISA dictionary
 246 // is validated to have keys from within the set of recognized ISAs.  Unknown
 247 // ISAs are allowed, but ignored and warnings are produced. It is also
 248 // validated
 249 // that it must have an entry to match the ISA specified in |sandbox_isa| or
 250 // have a fallback 'portable' entry if there is no match. Returns true if
 251 // |dictionary| is an ISA to URL map.  Sets |error_info| to something
 252 // descriptive if it fails.
 253 bool IsValidISADictionary(const Json::Value& dictionary,
 254                           const std::string& parent_key,
 255                           const std::string& sandbox_isa,
 256                           bool must_find_matching_entry,
 257                           bool nonsfi_enabled,
 258                           JsonManifest::ErrorInfo* error_info) {
 259   // An ISA to URL dictionary has to be an object.
 260   if (!dictionary.isObject()) {
 261     error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 262     error_info->string = std::string("manifest: ") + parent_key +
 263                          " property is not an ISA to URL dictionary";
 264     return false;
 265   }
 266   // Build the set of reserved ISA dictionary keys.
 267   const char** isaProperties;
 268   size_t isaPropertiesLength;
 269   if (sandbox_isa == kPortableKey) {
 270     // The known values for PNaCl ISA dictionaries in the manifest.
 271     static const char* kPnaclManifestISAProperties[] = {
 272       kPortableKey
 273     };
 274     isaProperties = kPnaclManifestISAProperties;
 275     isaPropertiesLength = arraysize(kPnaclManifestISAProperties);
 276   } else {
 277     // The known values for NaCl ISA dictionaries in the manifest.
 278     static const char* kNaClManifestISAProperties[] = {
 279       kX8632Key,
 280       kX8632NonSFIKey,
 281       kX8664Key,
 282       kX8664NonSFIKey,
 283       kArmKey,
 284       kArmNonSFIKey,
 285       // "portable" is here to allow checking that, if present, it can
 286       // only refer to an URL, such as for a data file, and not to
 287       // "pnacl-translate", which would cause the creation of a nexe.
 288       kPortableKey
 289     };
 290     isaProperties = kNaClManifestISAProperties;
 291     isaPropertiesLength = arraysize(kNaClManifestISAProperties);
 292   }
 293   // Check that entries in the dictionary are structurally correct.
 294   Json::Value::Members members = dictionary.getMemberNames();
 295   for (size_t i = 0; i < members.size(); ++i) {
 296     std::string property_name = members[i];
 297     Json::Value property_value = dictionary[property_name];
 298     std::string error_string;
 299     if (FindMatchingProperty(property_name,
 300                              isaProperties,
 301                              isaPropertiesLength)) {
 302       // For NaCl, arch entries can only be
 303       //     "arch/portable" : URLSpec
 304       // For PNaCl arch in "program" dictionary entries can be
 305       //     "portable" : { "pnacl-translate": URLSpec }
 306       //  or "portable" : { "pnacl-debug": URLSpec }
 307       // For PNaCl arch elsewhere, dictionary entries can only be
 308       //     "portable" : URLSpec
 309       if ((sandbox_isa != kPortableKey &&
 310            !IsValidUrlSpec(property_value, property_name, parent_key,
 311                            sandbox_isa, &error_string)) ||
 312           (sandbox_isa == kPortableKey &&
 313            parent_key == kProgramKey &&
 314            !IsValidPnaclTranslateSpec(property_value, property_name, parent_key,
 315                                       sandbox_isa, &error_string)) ||
 316           (sandbox_isa == kPortableKey &&
 317            parent_key != kProgramKey &&
 318            !IsValidUrlSpec(property_value, property_name, parent_key,
 319                            sandbox_isa, &error_string))) {
 320         error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 321         error_info->string = "manifest: " + error_string;
 322         return false;
 323       }
 324     } else {
 325       // For forward compatibility, we do not prohibit other keys being in
 326       // the dictionary, as they may be architectures supported in later
 327       // versions.  However, the value of these entries must be an URLSpec.
 328       VLOG(1) << "IsValidISADictionary: unrecognized key '"
 329               << property_name << "'.";
 330       if (!IsValidUrlSpec(property_value, property_name, parent_key,
 331                           sandbox_isa, &error_string)) {
 332         error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 333         error_info->string = "manifest: " + error_string;
 334         return false;
 335       }
 336     }
 337   }
 338
 339   if (sandbox_isa == kPortableKey) {
 340     if (!dictionary.isMember(kPortableKey)) {
 341       error_info->error = PP_NACL_ERROR_MANIFEST_PROGRAM_MISSING_ARCH;
 342       error_info->string = "manifest: no version of " + parent_key +
 343                            " given for portable.";
 344       return false;
 345     }
 346   } else if (must_find_matching_entry) {
 347     // TODO(elijahtaylor) add ISA resolver here if we expand ISAs to include
 348     // micro-architectures that can resolve to multiple valid sandboxes.
 349     bool has_isa = dictionary.isMember(sandbox_isa);
 350     bool has_nonsfi_isa =
 351         nonsfi_enabled && dictionary.isMember(GetNonSFIKey(sandbox_isa));
 352     bool has_portable = dictionary.isMember(kPortableKey);
 353
 354     if (!has_isa && !has_nonsfi_isa && !has_portable) {
 355       error_info->error = PP_NACL_ERROR_MANIFEST_PROGRAM_MISSING_ARCH;
 356       error_info->string = "manifest: no version of " + parent_key +
 357           " given for current arch and no portable version found.";
 358       return false;
 359     }
 360   }
 361   return true;
 362 }
 363
 364 void GrabUrlAndPnaclOptions(const Json::Value& url_spec,
 365                             std::string* url,
 366                             PP_PNaClOptions* pnacl_options) {
 367   *url = url_spec[kUrlKey].asString();
 368   pnacl_options->translate = PP_TRUE;
 369   if (url_spec.isMember(kOptLevelKey)) {
 370     int32_t opt_raw = url_spec[kOptLevelKey].asInt();
 371     // Currently only allow 0 or 2, since that is what we test.
 372     if (opt_raw <= 0)
 373       pnacl_options->opt_level = 0;
 374     else
 375       pnacl_options->opt_level = 2;
 376   }
 377 }
 378
 379 }  // namespace
 380
 381 JsonManifest::JsonManifest(const std::string& manifest_base_url,
 382                            const std::string& sandbox_isa,
 383                            bool nonsfi_enabled,
 384                            bool pnacl_debug)
 385     : manifest_base_url_(manifest_base_url),
 386       sandbox_isa_(sandbox_isa),
 387       nonsfi_enabled_(nonsfi_enabled),
 388       pnacl_debug_(pnacl_debug) { }
 389
 390 bool JsonManifest::Init(const std::string& manifest_json,
 391                         ErrorInfo* error_info) {
 392   CHECK(error_info);
 393
 394   Json::Reader reader;
 395   if (!reader.parse(manifest_json, dictionary_)) {
 396     std::string json_error = reader.getFormattedErrorMessages();
 397     error_info->error = PP_NACL_ERROR_MANIFEST_PARSING;
 398     error_info->string = "manifest JSON parsing failed: " + json_error;
 399     return false;
 400   }
 401   // Parse has ensured the string was valid JSON.  Check that it matches the
 402   // manifest schema.
 403   return MatchesSchema(error_info);
 404 }
 405
 406 bool JsonManifest::GetProgramURL(std::string* full_url,
 407                                  PP_PNaClOptions* pnacl_options,
 408                                  bool* uses_nonsfi_mode,
 409                                  ErrorInfo* error_info) const {
 410   if (!full_url)
 411     return false;
 412   CHECK(pnacl_options);
 413   CHECK(uses_nonsfi_mode);
 414   CHECK(error_info);
 415
 416   const Json::Value& program = dictionary_[kProgramKey];
 417   std::string nexe_url;
 418   if (!GetURLFromISADictionary(program,
 419                                kProgramKey,
 420                                &nexe_url,
 421                                pnacl_options,
 422                                uses_nonsfi_mode,
 423                                error_info)) {
 424     return false;
 425   }
 426
 427   // The contents of the manifest are resolved relative to the manifest URL.
 428   GURL base_gurl(manifest_base_url_);
 429   if (!base_gurl.is_valid())
 430     return false;
 431
 432   GURL resolved_gurl = base_gurl.Resolve(nexe_url);
 433   if (!resolved_gurl.is_valid()) {
 434     error_info->error = PP_NACL_ERROR_MANIFEST_RESOLVE_URL;
 435     error_info->string =
 436         "could not resolve url '" + nexe_url +
 437         "' relative to manifest base url '" + manifest_base_url_.c_str() +
 438         "'.";
 439     return false;
 440   }
 441   *full_url = resolved_gurl.possibly_invalid_spec();
 442   return true;
 443 }
 444
 445 void JsonManifest::GetPrefetchableFiles(
 446     std::vector<std::pair<std::string, std::string> >* out_files) const {
 447   const Json::Value& files = dictionary_[kFilesKey];
 448   if (!files.isObject())
 449     return;
 450
 451   Json::Value::Members keys = files.getMemberNames();
 452   for (size_t i = 0; i < keys.size(); ++i) {
 453     std::string full_url;
 454     PP_PNaClOptions unused_pnacl_options;  // pnacl does not support "files".
 455     // We skip invalid entries in "files".
 456     if (GetKeyUrl(files, keys[i], &full_url, &unused_pnacl_options)) {
 457       if (GURL(full_url).SchemeIs("chrome-extension"))
 458         out_files->push_back(std::make_pair(keys[i], full_url));
 459     }
 460   }
 461 }
 462
 463 bool JsonManifest::ResolveKey(const std::string& key,
 464                               std::string* full_url,
 465                               PP_PNaClOptions* pnacl_options) const {
 466   // key must be one of kProgramKey or kFileKey '/' file-section-key
 467   if (full_url == NULL || pnacl_options == NULL)
 468     return false;
 469
 470   if (key == kProgramKey)
 471     return GetKeyUrl(dictionary_, key, full_url, pnacl_options);
 472
 473   std::string::const_iterator p = std::find(key.begin(), key.end(), '/');
 474   if (p == key.end()) {
 475     VLOG(1) << "ResolveKey failed: invalid key, no slash: " << key;
 476     return false;
 477   }
 478
 479   // generalize to permit other sections?
 480   std::string prefix(key.begin(), p);
 481   if (prefix != kFilesKey) {
 482     VLOG(1) << "ResolveKey failed: invalid key, no \"files\" prefix: " << key;
 483     return false;
 484   }
 485
 486   const Json::Value& files = dictionary_[kFilesKey];
 487   if (!files.isObject()) {
 488     VLOG(1) << "ResolveKey failed: no \"files\" dictionary";
 489     return false;
 490   }
 491
 492   std::string rest(p + 1, key.end());
 493   if (!files.isMember(rest)) {
 494     VLOG(1) << "ResolveKey failed: no such \"files\" entry: " << key;
 495     return false;
 496   }
 497   return GetKeyUrl(files, rest, full_url, pnacl_options);
 498 }
 499
 500 bool JsonManifest::MatchesSchema(ErrorInfo* error_info) {
 501   if (!dictionary_.isObject()) {
 502     error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 503     error_info->string = "manifest: is not a json dictionary.";
 504     return false;
 505   }
 506   Json::Value::Members members = dictionary_.getMemberNames();
 507   for (size_t i = 0; i < members.size(); ++i) {
 508     // The top level dictionary entries valid in the manifest file.
 509     static const char* kManifestTopLevelProperties[] = { kProgramKey,
 510                                                          kInterpreterKey,
 511                                                          kFilesKey };
 512     std::string property_name = members[i];
 513     if (!FindMatchingProperty(property_name,
 514                               kManifestTopLevelProperties,
 515                               arraysize(kManifestTopLevelProperties))) {
 516       VLOG(1) << "JsonManifest::MatchesSchema: WARNING: unknown top-level "
 517               << "section '" << property_name << "' in manifest.";
 518     }
 519   }
 520
 521   // A manifest file must have a program section.
 522   if (!dictionary_.isMember(kProgramKey)) {
 523     error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 524     error_info->string = std::string("manifest: missing '") + kProgramKey +
 525                          "' section.";
 526     return false;
 527   }
 528
 529   // Validate the program section.
 530   // There must be a matching (portable or sandbox_isa_) entry for program for
 531   // NaCl.
 532   if (!IsValidISADictionary(dictionary_[kProgramKey],
 533                             kProgramKey,
 534                             sandbox_isa_,
 535                             true,
 536                             nonsfi_enabled_,
 537                             error_info)) {
 538     return false;
 539   }
 540
 541   // Validate the interpreter section (if given).
 542   // There must be a matching (portable or sandbox_isa_) entry for interpreter
 543   // for NaCl.
 544   if (dictionary_.isMember(kInterpreterKey)) {
 545     if (!IsValidISADictionary(dictionary_[kInterpreterKey],
 546                               kInterpreterKey,
 547                               sandbox_isa_,
 548                               true,
 549                               nonsfi_enabled_,
 550                               error_info)) {
 551       return false;
 552     }
 553   }
 554
 555   // Validate the file dictionary (if given).
 556   // The "files" key does not require a matching (portable or sandbox_isa_)
 557   // entry at schema validation time for NaCl.  This allows manifests to
 558   // specify resources that are only loaded for a particular sandbox_isa.
 559   if (dictionary_.isMember(kFilesKey)) {
 560     const Json::Value& files = dictionary_[kFilesKey];
 561     if (!files.isObject()) {
 562       error_info->error = PP_NACL_ERROR_MANIFEST_SCHEMA_VALIDATE;
 563       error_info->string = std::string("manifest: '") + kFilesKey +
 564                            "' is not a dictionary.";
 565     }
 566     Json::Value::Members members = files.getMemberNames();
 567     for (size_t i = 0; i < members.size(); ++i) {
 568       std::string file_name = members[i];
 569       if (!IsValidISADictionary(files[file_name],
 570                                 file_name,
 571                                 sandbox_isa_,
 572                                 false,
 573                                 nonsfi_enabled_,
 574                                 error_info)) {
 575         return false;
 576       }
 577     }
 578   }
 579   return true;
 580 }
 581
 582 bool JsonManifest::GetKeyUrl(const Json::Value& dictionary,
 583                              const std::string& key,
 584                              std::string* full_url,
 585                              PP_PNaClOptions* pnacl_options) const {
 586   DCHECK(full_url && pnacl_options);
 587   if (!dictionary.isMember(key)) {
 588     VLOG(1) << "GetKeyUrl failed: file " << key << " not found in manifest.";
 589     return false;
 590   }
 591   const Json::Value& isa_dict = dictionary[key];
 592   std::string relative_url;
 593   bool uses_nonsfi_mode;
 594   ErrorInfo ignored_error_info;
 595   if (!GetURLFromISADictionary(isa_dict, key, &relative_url,
 596                                pnacl_options, &uses_nonsfi_mode,
 597                                &ignored_error_info))
 598     return false;
 599
 600   // The contents of the manifest are resolved relative to the manifest URL.
 601   GURL base_gurl(manifest_base_url_);
 602   if (!base_gurl.is_valid())
 603     return false;
 604   GURL resolved_gurl = base_gurl.Resolve(relative_url);
 605   if (!resolved_gurl.is_valid())
 606     return false;
 607   *full_url = resolved_gurl.possibly_invalid_spec();
 608   return true;
 609 }
 610
 611 bool JsonManifest::GetURLFromISADictionary(const Json::Value& dictionary,
 612                                            const std::string& parent_key,
 613                                            std::string* url,
 614                                            PP_PNaClOptions* pnacl_options,
 615                                            bool* uses_nonsfi_mode,
 616                                            ErrorInfo* error_info) const {
 617   DCHECK(url && pnacl_options && error_info);
 618
 619   // When the application actually requests a resolved URL, we must have
 620   // a matching entry (sandbox_isa_ or portable) for NaCl.
 621   ErrorInfo ignored_error_info;
 622   if (!IsValidISADictionary(dictionary, parent_key, sandbox_isa_, true,
 623                             nonsfi_enabled_, &ignored_error_info)) {
 624     error_info->error = PP_NACL_ERROR_MANIFEST_RESOLVE_URL;
 625     error_info->string = "architecture " + sandbox_isa_ +
 626                          " is not found for file " + parent_key;
 627     return false;
 628   }
 629
 630   // The call to IsValidISADictionary() above guarantees that either
 631   // sandbox_isa_, its nonsfi mode, or kPortableKey is present in the
 632   // dictionary.
 633   *uses_nonsfi_mode = false;
 634   std::string chosen_isa;
 635   if (sandbox_isa_ == kPortableKey) {
 636     chosen_isa = kPortableKey;
 637   } else {
 638     std::string nonsfi_isa = GetNonSFIKey(sandbox_isa_);
 639     if (nonsfi_enabled_ && dictionary.isMember(nonsfi_isa)) {
 640       chosen_isa = nonsfi_isa;
 641       *uses_nonsfi_mode = true;
 642     } else if (dictionary.isMember(sandbox_isa_)) {
 643       chosen_isa = sandbox_isa_;
 644     } else if (dictionary.isMember(kPortableKey)) {
 645       chosen_isa = kPortableKey;
 646     } else {
 647       // Should not reach here, because the earlier IsValidISADictionary()
 648       // call checked that the manifest covers the current architecture.
 649       DCHECK(false);
 650       return false;
 651     }
 652   }
 653
 654   const Json::Value& isa_spec = dictionary[chosen_isa];
 655   // If the PNaCl debug flag is turned on, look for pnacl-debug entries first.
 656   // If found, mark that it is a debug URL. Otherwise, fall back to
 657   // checking for pnacl-translate URLs, etc. and don't mark it as a debug URL.
 658   if (pnacl_debug_ && isa_spec.isMember(kPnaclDebugKey)) {
 659     GrabUrlAndPnaclOptions(isa_spec[kPnaclDebugKey], url, pnacl_options);
 660     pnacl_options->is_debug = PP_TRUE;
 661   } else if (isa_spec.isMember(kPnaclTranslateKey)) {
 662     GrabUrlAndPnaclOptions(isa_spec[kPnaclTranslateKey], url, pnacl_options);
 663   } else {
 664     // NaCl
 665     *url = isa_spec[kUrlKey].asString();
 666     pnacl_options->translate = PP_FALSE;
 667   }
 668
 669   return true;
 670 }
 671
 672 }  // namespace nacl