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/** |
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* This file is part of the CernVM File System. |
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*/ |
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#ifndef CVMFS_MONITOR_H_ |
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#define CVMFS_MONITOR_H_ |
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#include <pthread.h> |
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#include <signal.h> |
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#include <sys/types.h> |
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#include <unistd.h> |
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#include <map> |
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#include <string> |
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#include "util/pipe.h" |
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#include "util/platform.h" |
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#include "util/pointer.h" |
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#include "util/single_copy.h" |
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/** |
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* This class can fork a watchdog process that listens on a pipe and prints a |
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* stackstrace into syslog, when cvmfs fails. The crash dump is also appended |
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* to the crash dump file, if the path is not empty. Singleton. |
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* |
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* The watchdog process if forked on Create and put on hold. Spawn() will start |
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* the supervision and set the crash dump path. It should be called from the |
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* final supervisee pid (after daemon etc.) but preferably before any threads |
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* are started. |
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* |
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* Note: logging should be set up before calling Create() |
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*/ |
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class Watchdog : SingleCopy { |
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public: |
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/** |
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* Crash cleanup handler signature. |
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*/ |
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typedef void (*FnOnCrash)(void); |
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static Watchdog *Create(FnOnCrash on_crash); |
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static pid_t GetPid(); |
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~Watchdog(); |
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void Spawn(const std::string &crash_dump_path); |
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/** |
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* Signals that watchdog should not receive. If it does, report and exit. |
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*/ |
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static int g_suppressed_signals[13]; |
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/** |
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* Signals used by crash signal handler. If received, create a stack trace. |
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*/ |
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static int g_crash_signals[8]; |
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private: |
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typedef std::map<int, struct sigaction> SigactionMap; |
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struct CrashData { |
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int signal; |
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int sys_errno; |
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pid_t pid; |
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}; |
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struct ControlFlow { |
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enum Flags { |
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kProduceStacktrace = 0, |
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kQuit, |
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kSupervise, |
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kUnknown, |
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}; |
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}; |
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/** |
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* Preallocated memory block to make sure that signal handler don't run into |
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* stack overflows. |
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*/ |
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static const unsigned kSignalHandlerStacksize = 2 * 1024 * 1024; // 2 MB |
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/** |
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* If the GDB/LLDB method of generating a stack trace fails, fall back to |
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* libc's backtrace with a maximum depth. |
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*/ |
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static const unsigned kMaxBacktrace = 64; |
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static Watchdog *instance_; |
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static Watchdog *Me() { return instance_; } |
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static void *MainWatchdogListener(void *data); |
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static void ReportSignalAndTerminate(int sig, siginfo_t *siginfo, |
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void *context); |
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static void SendTrace(int sig, siginfo_t *siginfo, void *context); |
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explicit Watchdog(FnOnCrash on_crash); |
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void Fork(); |
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bool WaitForSupervisee(); |
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SigactionMap SetSignalHandlers(const SigactionMap &signal_handlers); |
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void Supervise(); |
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void LogEmergency(std::string msg); |
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std::string ReportStacktrace(); |
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std::string GenerateStackTrace(pid_t pid); |
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std::string ReadUntilGdbPrompt(int fd_pipe); |
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bool spawned_; |
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std::string crash_dump_path_; |
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std::string exe_path_; |
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pid_t watchdog_pid_; |
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UniquePtr<Pipe<kPipeWatchdog> > pipe_watchdog_; |
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/// The supervisee makes sure its watchdog does not die |
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UniquePtr<Pipe<kPipeWatchdogSupervisor> > pipe_listener_; |
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/// Send the terminate signal to the listener |
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UniquePtr<Pipe<kPipeThreadTerminator> > pipe_terminate_; |
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pthread_t thread_listener_; |
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FnOnCrash on_crash_; |
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platform_spinlock lock_handler_; |
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stack_t sighandler_stack_; |
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SigactionMap old_signal_handlers_; |
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}; |
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#endif // CVMFS_MONITOR_H_ |
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