* initial version

install/demo/linux/daemon.pp

@@ -0,0 +1,142 @@
+{---------------------------------------------------------------------------
+                                 CncWare
+                           (c) Copyright 2000
+ ---------------------------------------------------------------------------
+  $Id$
+  Filename..: daemon.pp
+  Programmer: Ken J. Wright
+  Date......: 03/21/2000
+
+  Purpose - Program to demonstrate construction of a Linux daemon.
+
+  Usage:
+    1) Compile this program.
+    2) Run it. You will be immediately returned to a command prompt.
+    3) Issue the command: ps ax|grep daemon. This will show you the process
+       id of the program "daemon" that you just ran.
+    4) Issue the command: tail -f daemon.log. This let's you watch the log file
+       being filled with the message in the code below. Press Ctrl/c to break
+       out of the tail command.
+    5) Issue the command: kill -HUP pid. pid is the process number you saw with
+       the ps command above. You will see that a new log file has been created.
+    6) Issue the command: kill -TERM pid. This will stop the daemon. Issuing the
+       ps command above, you will see that the daemon is no longer running.
+
+-------------------------------<< REVISIONS >>--------------------------------
+  Ver  |    Date    | Prog | Decription
+-------+------------+------+--------------------------------------------------
+  1.00 | 03/21/2000 | kjw  | Initial release.
+  1.01 | 03/21/2000 | kjw  | Forgot to close input, output, & stderr.
+------------------------------------------------------------------------------
+}
+Program Daemon;
+uses linux;
+Var
+   { vars for daemonizing }
+   bHup,
+   bTerm : boolean;
+   fLog : text;
+   logname : string;
+   aOld,
+   aTerm,
+   aHup : pSigActionRec;
+   ps1  : psigset;
+   sSet : cardinal;
+   pid : longint;
+   secs : longint;
+   hr,mn,sc,sc100 : word;
+
+{ handle SIGHUP & SIGTERM }
+procedure DoSig(sig : longint);cdecl;
+begin
+   case sig of
+      SIGHUP : bHup := true;
+      SIGTERM : bTerm := true;
+   end;
+end;
+
+{ open the log file }
+Procedure NewLog;
+Begin
+   Assign(fLog,logname);
+   Rewrite(fLog);
+   GetTime(hr,mn,sc,sc100);
+   Writeln(flog,'Log created at ',hr:0,':',mn:0,':',sc:0);
+   Close(fLog);
+End;
+
+Begin
+   logname := 'daemon.log';
+   secs := 10;
+
+   { set global daemon booleans }
+   bHup := true; { to open log file }
+   bTerm := false;
+
+   { block all signals except -HUP & -TERM }
+   sSet := $ffffbffe;
+   ps1 := @sSet;
+   sigprocmask(sig_block,ps1,nil);
+
+   { setup the signal handlers }
+   new(aOld);
+   new(aHup);
+   new(aTerm);
+   aTerm^.sa_handler := @DoSig;
+   aTerm^.sa_mask := 0;
+   aTerm^.sa_flags := 0;
+   aTerm^.sa_restorer := nil;
+   aHup^.sa_handler := @DoSig;
+   aHup^.sa_mask := 0;
+   aHup^.sa_flags := 0;
+   aHup^.sa_restorer := nil;
+   SigAction(SIGTERM,aTerm,aOld);
+   SigAction(SIGHUP,aHup,aOld);
+
+   { daemonize }
+   pid := Fork;
+   Case pid of
+      0 : Begin { we are in the child }
+         Close(input);  { close standard in }
+         Close(output); { close standard out }
+         Assign(output,'/dev/null');
+         ReWrite(output);
+         Close(stderr); { close standard error }
+         Assign(stderr,'/dev/null');
+         ReWrite(stderr);
+      End;
+      -1 : secs := 0;     { forking error, so run as non-daemon }
+      Else Halt;          { successful fork, so parent dies }
+   End;
+
+   { begin processing loop }
+   Repeat
+      If bHup Then Begin
+         {$I-}
+         Close(fLog);
+         {$I+}
+         NewLog;
+         bHup := false;
+      End;
+      {----------------------}
+      { Do your daemon stuff }
+      GetTime(hr,mn,sc,sc100);
+      Append(flog);
+      Writeln(flog,'daemon code activated at ',hr:0,':',mn:0,':',sc:0);
+      Close(fLog);
+      { the following output goes to the bit bucket }
+      Writeln('daemon code activated at ',hr:0,':',mn:0,':',sc:0);
+      {----------------------}
+      If bTerm Then
+         BREAK
+      Else
+         { wait a while }
+         Select(0,nil,nil,nil,secs*1000);
+   Until bTerm;
+End.
+{
+  $Log$
+  Revision 1.1  2000-03-21 21:41:19  peter
+    * initial version
+
+}