From 58c7519598b39f58ec2ff1a821ace113f523b0fa Mon Sep 17 00:00:00 2001
From: Mark Mentovai <mark@chromium.org>
Date: Thu, 12 Mar 2015 19:34:05 -0400
Subject: [PATCH] Add a magic number to settings.dat for better identification.
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“1” is probably one of the more common things for files to begin with.

R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/1007433003
---
 client/settings.cc | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/client/settings.cc b/client/settings.cc
index b4e5f434..aa2c4f8f 100644
--- a/client/settings.cc
+++ b/client/settings.cc
@@ -28,19 +28,24 @@
 namespace crashpad {
 
 struct ALIGNAS(4) Settings::Data {
-  static const uint16_t kSettingsVersion = 1;
+  static const uint32_t kSettingsMagic = 'CPds';
+  static const uint32_t kSettingsVersion = 1;
 
   enum Options : uint32_t {
     kUploadsEnabled = 1 << 0,
   };
 
-  Data() : version(kSettingsVersion),
+  Data() : magic(kSettingsMagic),
+           version(kSettingsVersion),
            options(0),
+           padding_0(0),
            last_upload_attempt_time(0),
            client_id() {}
 
+  uint32_t magic;
   uint32_t version;
   uint32_t options;
+  uint32_t padding_0;
   uint64_t last_upload_attempt_time;  // time_t
   UUID client_id;
 };
@@ -193,6 +198,11 @@ bool Settings::ReadSettings(FileHandle handle, Data* out_data) {
   if (!LoggingReadFile(handle, out_data, sizeof(*out_data)))
     return false;
 
+  if (out_data->magic != Data::kSettingsMagic) {
+    LOG(ERROR) << "Settings magic is not " << Data::kSettingsMagic;
+    return false;
+  }
+
   if (out_data->version != Data::kSettingsVersion) {
     LOG(ERROR) << "Settings version is not " << Data::kSettingsVersion;
     return false;