I’m just curious if it is possible to create a Linux daemon with Elements?
I’ve never attempted any Linux development but it’s something that I’m considering for the future.
very much so, yes. we’re lookin at providing a sample or template soon (@jonaa), but in essence, a unix dæmon really is just a command line app, so that template should be a good starting point…
Cursory googling finds a few links such as http://www.unixguide.net/unix/programming/1.7.shtml, http://www.enderunix.org/docs/eng/daemon.php and that should pretty direct translate to any of the Elements languages, when using Island/Linux As promised, I’ll have someone look at turning this into a template, sample and/or tutorial next week, but maybe these help to get you started now.
(Pro tip: Paste & Convert Objective-C also handles most regular. C code, as well.
This is a rough (untested) port from http://www.enderunix.org/docs/eng/daemon.php. All compiles except that mask doesn’t;t seem to be defined; I’ll have someone check into why.
namespace DæmonApplication;
uses
rtl;
type
Program = class
public
class method Main(args: array of String): Int32;
begin
// add your own code here
writeLn('The magic happens here.');
var f := fork();
if f <0 then exit(1); /* fork error */
if f > 0 then exit(0); /* parent exits */
/* child (daemon) continues */
setsid(); /* obtain a new process group */
for d: Integer := getdtablesize()-1 downto 0 do
close(d); /* close all descriptors */
var i := open("/dev/null", O_RDWR); /* open stdin */
dup(i); /* stdout */
dup(i); /* stderr */
umask($17); /* $17 = octal 27 | This will restrict file creation mode to 750 (complement of 027). */
chdir("/servers/");
var lfp := open('exampled.lock', O_RDWR or O_CREAT, 416);
if lfp < 0 then exit(1);
if lockf(lfp, F_TLOCK, 0) < 0 then exit(0);
//sprintf(str, '%d'#10, getpid());
//&write(lfp, str, strlen(str));
//signal(SIG_IGN,SIGCHLD); /* child terminate signal */
method Signal_Handler(sig: Integer);
begin
case sig of
SIGHUP: ; /* rehash the server */
SIGTERM: rtl.exit(0); /* finalize the server */
end;
end;
signal(SIGHUP, @Signal_Handler); /* hangup signal */
signal(SIGTERM, @Signal_Handler); /* software termination signal from kill */
method log_message(filename: ^AnsiChar; message: ^AnsiChar);
begin
var logfile: ^FILE;
logfile := fopen(filename, 'a');
if assigned(logfile) then begin
fprintf(logfile, '%s'#10, message);
fclose(logfile);
end;
end;
log_message("conn.log", "connection accepted");
log_message("error.log", "can not open file");
openlog("mydaemon",LOG_PID,LOG_DAEMON);
//syslog(LOG_INFO, "Connection from host %d", callinghostname);
syslog(LOG_ALERT, "Database Error !");
closelog();
end;
end;
end.
Thank you very much!
1 Like
any time!
let me know what works and what (if anything) doesn’t…