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      1 // Copyright (c) 2011, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
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      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // crash_generator.h: Define the google_breakpad::CrashGenerator class,
     31 // which is used to generate a crash (and a core dump file) for testing.
     32 
     33 #ifndef COMMON_LINUX_TESTS_CRASH_GENERATOR_H_
     34 #define COMMON_LINUX_TESTS_CRASH_GENERATOR_H_
     35 
     36 #include <sys/resource.h>
     37 
     38 #include <string>
     39 
     40 #include "common/tests/auto_tempdir.h"
     41 #include "common/using_std_string.h"
     42 
     43 namespace google_breakpad {
     44 
     45 // A utility class for generating a crash (and a core dump file) for
     46 // testing. It creates a child process with the specified number of
     47 // threads, which is then termainated by the specified signal. A core
     48 // dump file is expected to be created upon the termination of the child
     49 // process, which can then be used for testing code that processes core
     50 // dump files.
     51 class CrashGenerator {
     52  public:
     53   CrashGenerator();
     54 
     55   ~CrashGenerator();
     56 
     57   // Returns true if a core dump file named 'core' will be generated in
     58   // the current directory for a test that produces a crash by checking
     59   // if /proc/sys/kernel/core_pattern has the default value 'core'.
     60   bool HasDefaultCorePattern() const;
     61 
     62   // Returns the expected path of the core dump file.
     63   string GetCoreFilePath() const;
     64 
     65   // Returns the directory of a copy of proc files of the child process.
     66   string GetDirectoryOfProcFilesCopy() const;
     67 
     68   // Creates a crash (and a core dump file) by creating a child process with
     69   // |num_threads| threads, and the terminating the child process by sending
     70   // a signal with number |crash_signal| to the |crash_thread|-th thread.
     71   // Returns true on success.
     72   bool CreateChildCrash(unsigned num_threads, unsigned crash_thread,
     73                         int crash_signal, pid_t* child_pid);
     74 
     75   // Returns the thread ID of the |index|-th thread in the child process.
     76   // This method does not validate |index|.
     77   pid_t GetThreadId(unsigned index) const;
     78 
     79  private:
     80   // Copies the following proc files of the process with |pid| to the directory
     81   // at |path|: auxv, cmdline, environ, maps, status
     82   // The directory must have been created. Returns true on success.
     83   bool CopyProcFiles(pid_t pid, const char* path) const;
     84 
     85   // Creates |num_threads| threads in the child process.
     86   void CreateThreadsInChildProcess(unsigned num_threads);
     87 
     88   // Sets the maximum size of core dump file (both the soft and hard limit)
     89   // to |limit| bytes. Returns true on success.
     90   bool SetCoreFileSizeLimit(rlim_t limit) const;
     91 
     92   // Creates a shared memory of |memory_size| bytes for communicating thread
     93   // IDs between the parent and child process. Returns true on success.
     94   bool MapSharedMemory(size_t memory_size);
     95 
     96   // Releases any shared memory created by MapSharedMemory(). Returns true on
     97   // success.
     98   bool UnmapSharedMemory();
     99 
    100   // Returns the pointer to the thread ID of the |index|-th thread in the child
    101   // process. This method does not validate |index|.
    102   pid_t* GetThreadIdPointer(unsigned index);
    103 
    104   // Temporary directory in which a core file is generated.
    105   AutoTempDir temp_dir_;
    106 
    107   // Shared memory for communicating thread IDs between the parent and
    108   // child process.
    109   void* shared_memory_;
    110 
    111   // Number of bytes mapped for |shared_memory_|.
    112   size_t shared_memory_size_;
    113 };
    114 
    115 }  // namespace google_breakpad
    116 
    117 #endif  // COMMON_LINUX_TESTS_CRASH_GENERATOR_H_
    118