Linux: Add Breakpad client.

breakpad/linux/exception_handler.h

Index: breakpad/linux/exception_handler.h
diff --git a/breakpad/linux/exception_handler.h b/breakpad/linux/exception_handler.h
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+// Copyright (c) 2009, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
+#define CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
+
+#include <vector>
+#include <string>
+
+#include <signal.h>
+
+namespace google_breakpad {
+
+// ExceptionHandler
+//
+// ExceptionHandler can write a minidump file when an exception occurs,
+// or when WriteMinidump() is called explicitly by your program.
+//
+// To have the exception handler write minidumps when an uncaught exception
+// (crash) occurs, you should create an instance early in the execution
+// of your program, and keep it around for the entire time you want to
+// have crash handling active (typically, until shutdown).
+// (NOTE): There should be only be one this kind of exception handler
+// object per process.
+//
+// If you want to write minidumps without installing the exception handler,
+// you can create an ExceptionHandler with install_handler set to false,
+// then call WriteMinidump.  You can also use this technique if you want to
+// use different minidump callbacks for different call sites.
+//
+// In either case, a callback function is called when a minidump is written,
+// which receives the unqiue id of the minidump.  The caller can use this
+// id to collect and write additional application state, and to launch an
+// external crash-reporting application.
+//
+// Caller should try to make the callbacks as crash-friendly as possible,
+// it should avoid use heap memory allocation as much as possible.
+class ExceptionHandler {
+ public:
+  // A callback function to run before Breakpad performs any substantial
+  // processing of an exception.  A FilterCallback is called before writing
+  // a minidump.  context is the parameter supplied by the user as
+  // callback_context when the handler was created.
+  //
+  // If a FilterCallback returns true, Breakpad will continue processing,
+  // attempting to write a minidump.  If a FilterCallback returns false,
+  // Breakpad  will immediately report the exception as unhandled without
+  // writing a minidump, allowing another handler the opportunity to handle it.
+  typedef bool (*FilterCallback)(void *context);
+
+  // A callback function to run after the minidump has been written.
+  // minidump_id is a unique id for the dump, so the minidump
+  // file is <dump_path>\<minidump_id>.dmp.  context is the parameter supplied
+  // by the user as callback_context when the handler was created.  succeeded
+  // indicates whether a minidump file was successfully written.
+  //
+  // If an exception occurred and the callback returns true, Breakpad will
+  // treat the exception as fully-handled, suppressing any other handlers from
+  // being notified of the exception.  If the callback returns false, Breakpad
+  // will treat the exception as unhandled, and allow another handler to handle
+  // it. If there are no other handlers, Breakpad will report the exception to
+  // the system as unhandled, allowing a debugger or native crash dialog the
+  // opportunity to handle the exception.  Most callback implementations
+  // should normally return the value of |succeeded|, or when they wish to
+  // not report an exception of handled, false.  Callbacks will rarely want to
+  // return true directly (unless |succeeded| is true).
+  typedef bool (*MinidumpCallback)(const char *dump_path,
+                                   const char *minidump_id,
+                                   void *context,
+                                   bool succeeded);
+
+  // In certain cases, a user may wish to handle the generation of the minidump
+  // themselves. In this case, they can install a handler callback which is
+  // called when a crash has occured. If this function returns true, no other
+  // processing of occurs and the process will shortly be crashed. If this
+  // returns false, the normal processing continues.
+  typedef bool (*HandlerCallback)(const void* crash_context,
+                                  size_t crash_context_size,
+                                  void* context);
+
+  // Creates a new ExceptionHandler instance to handle writing minidumps.
+  // Before writing a minidump, the optional filter callback will be called.
+  // Its return value determines whether or not Breakpad should write a
+  // minidump.  Minidump files will be written to dump_path, and the optional
+  // callback is called after writing the dump file, as described above.
+  // If install_handler is true, then a minidump will be written whenever
+  // an unhandled exception occurs.  If it is false, minidumps will only
+  // be written when WriteMinidump is called.
+  ExceptionHandler(const std::string &dump_path,
+                   FilterCallback filter, MinidumpCallback callback,
+                   void *callback_context,
+                   bool install_handler);
+  ~ExceptionHandler();
+
+  // Get and set the minidump path.
+  std::string dump_path() const { return dump_path_; }
+  void set_dump_path(const std::string &dump_path) {
+    dump_path_ = dump_path;
+    dump_path_c_ = dump_path_.c_str();
+    UpdateNextID();
+  }
+
+  void set_crash_handler(HandlerCallback callback) {
+    crash_handler_ = callback;
+  }
+
+  // Writes a minidump immediately.  This can be used to capture the
+  // execution state independently of a crash.  Returns true on success.
+  bool WriteMinidump();
+
+  // Convenience form of WriteMinidump which does not require an
+  // ExceptionHandler instance.
+  static bool WriteMinidump(const std::string &dump_path,
+                            MinidumpCallback callback,
+                            void *callback_context);
+
+  // This structure is passed to minidump_writer.h:WriteMinidump via an opaque
+  // blob. It shouldn't be needed in any user code.
+  struct CrashContext {
+    siginfo_t siginfo;
+    pid_t tid;  // the crashing thread.
+    struct ucontext context;
+  };
+
+ private:
+  bool InstallHandlers();
+  void UninstallHandlers();
+  void PreresolveSymbols();
+
+  void UpdateNextID();
+  static void SignalHandler(int sig, siginfo_t* info, void* uc);
+  bool HandleSignal(int sig, siginfo_t* info, void* uc);
+  static int ThreadEntry(void* arg);
+  bool DoDump(pid_t crashing_process, const void* context,
+              size_t context_size);
+
+  const FilterCallback filter_;
+  const MinidumpCallback callback_;
+  void* const callback_context_;
+
+  std::string dump_path_;
+  std::string next_minidump_path_;
+  std::string next_minidump_id_;
+
+  // Pointers to C-string representations of the above. These are set
+  // when the above are set so we can avoid calling c_str during
+  // an exception.
+  const char* dump_path_c_;
+  const char* next_minidump_path_c_;
+  const char* next_minidump_id_c_;
+
+  const bool handler_installed_;
+  void* signal_stack;  // the handler stack.
+  HandlerCallback crash_handler_;
+
+  // The global exception handler stack. This is need becuase there may exist
+  // multiple ExceptionHandler instances in a process. Each will have itself
+  // registered in this stack.
+  static std::vector<ExceptionHandler*> *handler_stack_;
+  // The index of the handler that should handle the next exception.
+  static unsigned handler_stack_index_;
+  static pthread_mutex_t handler_stack_mutex_;
+
+  // A vector of the old signal handlers. The void* is a pointer to a newly
+  // allocated sigaction structure to avoid pulling in too many includes.
+  std::vector<std::pair<int, void *> > old_handlers_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_