src/ipc/Kid.h

   1 /*
   2  * Copyright (C) 1996-2021 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 char *role, const int id);
  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's role and ID formatted for use as a process name
  78     SBuf processName() const;
  79
  80     /// \returns kid's role and ID summary; usable as a --kid parameter value
  81     SBuf gist() const;
  82
  83 private:
  84     void reportStopped() const;
  85
  86     // Information preserved across restarts
  87     SBuf processRole;
  88     int processId = 0;
  89     int badFailures = 0; ///< number of "repeated frequent" failures
  90
  91     // Information specific to a running or stopped kid
  92     pid_t  pid = -1; ///< current (for a running kid) or last (for stopped kid) PID
  93     time_t startTime = 0; ///< last start time
  94     time_t stopTime = 0; ///< last termination time
  95     bool isRunning = false; ///< whether the kid is assumed to be alive
  96     PidStatus status = 0; ///< exit status of a stopped kid
  97 };
  98
  99 // TODO: processes may not be kids; is there a better place to put this?
 100
 101 /// process kinds
 102 typedef enum {
 103     pkOther  = 0, ///< we do not know or do not care
 104     pkCoordinator = 1, ///< manages all other kids
 105     pkWorker = 2, ///< general-purpose worker bee
 106     pkDisker = 4, ///< cache_dir manager
 107     pkHelper = 8  ///< general-purpose helper child
 108 } ProcessKind;
 109
 110 /// ProcessKind for the current process
 111 extern int TheProcessKind;
 112
 113 #endif /* SQUID_IPC_KID_H */
 114