src/ipc/Kid.h

   1 /*
   2  * Copyright (C) 1996-2018 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_IPC_KID_H
  10 #define SQUID_IPC_KID_H
  11
  12 #include "SquidString.h"
  13 #include "tools.h"
  14
  15 /// Squid child, including current forked process info and
  16 /// info persistent across restarts
  17 class Kid
  18 {
  19 public:
  20
  21     /// keep restarting until the number of bad failures exceed this limit
  22     enum { badFailureLimit = 4 };
  23
  24     /// slower start failures are not "frequent enough" to be counted as "bad"
  25     enum { fastFailureTimeLimit = 10 }; // seconds
  26
  27 public:
  28     Kid();
  29
  30     Kid(const String& kid_name);
  31
  32     /// called when this kid got started, records PID
  33     void start(pid_t cpid);
  34
  35     /// called when kid terminates, sets exiting status
  36     void stop(PidStatus const exitStatus);
  37
  38     /// returns true if tracking of kid is stopped
  39     bool running() const;
  40
  41     /// returns true if master should restart this kid
  42     bool shouldRestart() const;
  43
  44     /// returns current pid for a running kid and last pid for a stopped kid
  45     pid_t getPid() const;
  46
  47     /// whether the failures are "repeated and frequent"
  48     bool hopeless() const;
  49
  50     /// forgets all past failures, ensuring that we are not hopeless()
  51     void forgetFailures() { badFailures = 0; }
  52
  53     /// \returns the time since process termination
  54     time_t deathDuration() const;
  55
  56     /// returns true if the process terminated normally
  57     bool calledExit() const;
  58
  59     /// returns the exit status of the process
  60     int exitStatus() const;
  61
  62     /// whether the process exited with a given exit status code
  63     bool calledExit(int code) const;
  64
  65     /// whether the process exited with code 0
  66     bool exitedHappy() const;
  67
  68     /// returns true if the kid was terminated by a signal
  69     bool signaled() const;
  70
  71     /// returns the number of the signal that caused the kid to terminate
  72     int termSignal() const;
  73
  74     /// whether the process was terminated by a given signal
  75     bool signaled(int sgnl) const;
  76
  77     /// returns kid name
  78     const String& name() const;
  79
  80 private:
  81     void reportStopped() const;
  82
  83     // Information preserved across restarts
  84     String theName; ///< process name
  85     int badFailures; ///< number of "repeated frequent" failures
  86
  87     // Information specific to a running or stopped kid
  88     pid_t  pid; ///< current (for a running kid) or last (for stopped kid) PID
  89     time_t startTime; ///< last start time
  90     time_t stopTime = 0; ///< last termination time
  91     bool   isRunning; ///< whether the kid is assumed to be alive
  92     PidStatus status; ///< exit status of a stopped kid
  93 };
  94
  95 // TODO: processes may not be kids; is there a better place to put this?
  96
  97 /// process kinds
  98 typedef enum {
  99     pkOther  = 0, ///< we do not know or do not care
 100     pkCoordinator = 1, ///< manages all other kids
 101     pkWorker = 2, ///< general-purpose worker bee
 102     pkDisker = 4, ///< cache_dir manager
 103     pkHelper = 8  ///< general-purpose helper child
 104 } ProcessKind;
 105
 106 /// ProcessKind for the current process
 107 extern int TheProcessKind;
 108
 109 #endif /* SQUID_IPC_KID_H */
 110