crash-reporter: Avoid writing through symlinks.

crash_collector.h

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef _CRASH_REPORTER_CRASH_COLLECTOR_H_
 #define _CRASH_REPORTER_CRASH_COLLECTOR_H_
 
 #include <sys/stat.h>
 
 #include <map>
@@ skipping 21 matching lines @@
                   IsFeedbackAllowedFunction is_metrics_allowed,
                   SystemLogging *logger);
 
  protected:
   friend class CrashCollectorTest;
   FRIEND_TEST(CrashCollectorTest, CheckHasCapacityCorrectBasename);
   FRIEND_TEST(CrashCollectorTest, CheckHasCapacityStrangeNames);
   FRIEND_TEST(CrashCollectorTest, CheckHasCapacityUsual);
   FRIEND_TEST(CrashCollectorTest, GetCrashDirectoryInfo);
   FRIEND_TEST(CrashCollectorTest, GetCrashPath);
+  FRIEND_TEST(CrashCollectorTest, ForkExecAndPipe);
   FRIEND_TEST(CrashCollectorTest, FormatDumpBasename);
   FRIEND_TEST(CrashCollectorTest, Initialize);
   FRIEND_TEST(CrashCollectorTest, MetaData);
   FRIEND_TEST(CrashCollectorTest, ReadKeyValueFile);
   FRIEND_TEST(CrashCollectorTest, Sanitize);
+  FRIEND_TEST(CrashCollectorTest, WriteNewFile);
 
   // Set maximum enqueued crashes in a crash directory.
   static const int kMaxCrashDirectorySize;
 
+  // Writes |data| of |size| to |filename|, which must be a new file.
+  // If the file already exists or writing fails, return a negative value.
+  // Otherwise returns the number of bytes written.
+  int WriteNewFile(const FilePath &filename, const char *data, int size);
+
+  int ForkExecAndPipe(std::vector<const char *> &arguments,
+                      const char *output_file);
+
   // Return a filename that has only [a-z0-1_] characters by mapping
   // all others into '_'.
   std::string Sanitize(const std::string &name);
 
   // For testing, set the directory always returned by
   // GetCreatedCrashDirectoryByEuid.
   void ForceCrashDirectory(const char *forced_directory) {
     forced_crash_directory_ = forced_directory;
   }
 
@@ skipping 49 matching lines @@
 
   CountCrashFunction count_crash_function_;
   IsFeedbackAllowedFunction is_feedback_allowed_function_;
   SystemLogging *logger_;
   std::string extra_metadata_;
   const char *forced_crash_directory_;
   const char *lsb_release_;
 };
 
 #endif  // _CRASH_REPORTER_CRASH_COLLECTOR_H_