Revert 285661 "Remove some dead app host code."

trunk/src/chrome/installer/util/google_update_util.cc

Index: trunk/src/chrome/installer/util/google_update_util.cc
===================================================================
--- trunk/src/chrome/installer/util/google_update_util.cc	(revision 285705)
+++ trunk/src/chrome/installer/util/google_update_util.cc	(working copy)
@@ -4,19 +4,28 @@
 
 #include "chrome/installer/util/google_update_util.h"
 
+#include <algorithm>
+#include <map>
+#include <utility>
+#include <vector>
+
 #include "base/command_line.h"
+#include "base/environment.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/strings/string16.h"
+#include "base/strings/string_split.h"
 #include "base/time/time.h"
 #include "base/win/registry.h"
 #include "base/win/scoped_handle.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_version.h"
+#include "chrome/installer/launcher_support/chrome_launcher_support.h"
 #include "chrome/installer/util/browser_distribution.h"
 #include "chrome/installer/util/google_update_constants.h"
 #include "chrome/installer/util/google_update_settings.h"
@@ -32,6 +41,9 @@
 
 const int kGoogleUpdateTimeoutMs = 20 * 1000;
 
+const char kEnvVariableUntrustedData[] = "GoogleUpdateUntrustedData";
+const int kUntrustedDataMaxLength = 4096;
+
 // Returns true if Google Update is present at the given level.
 bool IsGoogleUpdatePresent(bool system_install) {
   // Using the existence of version key in the registry to decide.
@@ -108,6 +120,73 @@
   return success;
 }
 
+bool IsNotPrintable(unsigned char c) {
+  return c < 32 || c >= 127;
+}
+
+// Returns whether or not |s| consists of printable characters.
+bool IsStringPrintable(const std::string& s) {
+  return std::find_if(s.begin(), s.end(), IsNotPrintable) == s.end();
+}
+
+bool IsIllegalUntrustedDataKeyChar(unsigned char c) {
+  return !(c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z' ||
+           c >= '0' && c <= '9' || c == '-' || c == '_' || c == '$');
+}
+
+// Returns true if |key| from untrusted data is valid.
+bool IsUntrustedDataKeyValid(const std::string& key) {
+  return std::find_if(key.begin(), key.end(), IsIllegalUntrustedDataKeyChar)
+      == key.end();
+}
+
+// Parses |data_string| as key-value pairs and overwrites |untrusted_data| with
+// the result. Returns true if the data could be parsed.
+bool ParseUntrustedData(
+    const std::string& data_string,
+    std::map<std::string, std::string>* untrusted_data) {
+  DCHECK(untrusted_data);
+  if (data_string.length() > kUntrustedDataMaxLength ||
+      !IsStringPrintable(data_string)) {
+    LOG(ERROR) << "Invalid value in untrusted data string.";
+    return false;
+  }
+
+  VLOG(1) << "Untrusted data string: " << data_string;
+
+  std::vector<std::pair<std::string, std::string> > kv_pairs;
+  if (!base::SplitStringIntoKeyValuePairs(data_string, '=', '&', &kv_pairs)) {
+    LOG(ERROR) << "Failed to parse untrusted data: " << data_string;
+    return false;
+  }
+
+  untrusted_data->clear();
+  std::vector<std::pair<std::string, std::string> >::const_iterator it;
+  for (it = kv_pairs.begin(); it != kv_pairs.end(); ++it) {
+    const std::string& key(it->first);
+    // TODO(huangs): URL unescape |value|.
+    const std::string& value(it->second);
+    if (IsUntrustedDataKeyValid(key) && IsStringPrintable(value))
+      (*untrusted_data)[key] = value;
+    else
+      LOG(ERROR) << "Illegal character found in untrusted data.";
+  }
+  return true;
+}
+
+// Reads and parses untrusted data passed from Google Update as key-value
+// pairs, then overwrites |untrusted_data_map| with the result.
+// Returns true if data are successfully read.
+bool GetGoogleUpdateUntrustedData(
+    std::map<std::string, std::string>* untrusted_data) {
+  scoped_ptr<base::Environment> env(base::Environment::Create());
+  std::string data_string;
+  if (!env || !env->GetVar(kEnvVariableUntrustedData, &data_string))
+    return false;
+
+  return ParseUntrustedData(data_string, untrusted_data);
+}
+
 }  // namespace
 
 bool EnsureUserLevelGoogleUpdatePresent() {
@@ -187,4 +266,25 @@
   }
 }
 
+std::string GetUntrustedDataValue(const std::string& key) {
+  std::map<std::string, std::string> untrusted_data;
+  if (GetGoogleUpdateUntrustedData(&untrusted_data)) {
+    std::map<std::string, std::string>::const_iterator data_it(
+        untrusted_data.find(key));
+    if (data_it != untrusted_data.end())
+      return data_it->second;
+  }
+
+  return std::string();
+}
+
+std::string GetUntrustedDataValueFromTag(const std::string& tag,
+                                         const std::string& key) {
+  std::map<std::string, std::string> untrusted_data;
+  if (ParseUntrustedData(tag, &untrusted_data))
+    return untrusted_data[key];
+
+  return std::string();
+}
+
 }  // namespace google_update