Commit | Line | Data |
5231273c |
1 | use strict; |
2 | use warnings; |
18cc5c89 |
3 | package MooseX::Daemonize::Core; |
5231273c |
4 | |
4327fe98 |
5 | use MooseX::Getopt; # to load the NoGetopt metaclass |
18cc5c89 |
6 | use Moose::Role; |
7 | |
ea9485d8 |
8 | use POSIX (); |
18cc5c89 |
9 | |
10 | has is_daemon => ( |
4327fe98 |
11 | # NOTE: |
12 | # this should never be accessible |
13 | # from the command line |
14 | # - SL |
15 | metaclass => 'NoGetopt', |
16 | isa => 'Bool', |
17 | is => 'rw', |
18 | default => sub { 0 }, |
18cc5c89 |
19 | ); |
20 | |
2ecc2ccb |
21 | has ignore_zombies => ( |
22 | metaclass => 'Getopt', |
23 | isa => 'Bool', |
24 | is => 'rw', |
25 | default => sub { 0 }, |
26 | ); |
27 | |
28 | has no_double_fork => ( |
29 | metaclass => 'Getopt', |
30 | isa => 'Bool', |
31 | is => 'rw', |
32 | default => sub { 0 }, |
33 | ); |
34 | |
35 | has dont_close_all_files => ( |
36 | metaclass => 'Getopt', |
37 | isa => 'Bool', |
38 | is => 'rw', |
39 | default => sub { 0 }, |
40 | ); |
41 | |
42 | sub _get_options { |
43 | my ($self, %options) = @_; |
b37fcc5f |
44 | # backwards compatibility.. old code might be calling daemon_fork/_detach with options |
2ecc2ccb |
45 | foreach my $opt (qw( ignore_zombies no_double_fork dont_close_all_files )) { |
46 | $self->$opt( $options{ $opt } ) if ( defined $options{ $opt } ); |
47 | } |
48 | } |
49 | |
50 | |
d8985b7d |
51 | sub daemon_fork { |
52 | my ($self, %options) = @_; |
53 | |
2ecc2ccb |
54 | $self->_get_options( %options ); |
55 | |
d8985b7d |
56 | $SIG{CHLD} = 'IGNORE' |
2ecc2ccb |
57 | if $self->ignore_zombies;; |
d8985b7d |
58 | |
129f5643 |
59 | if (my $pid = fork) { |
60 | return $pid; |
61 | } |
62 | else { |
289fcbc7 |
63 | $self->is_daemon(1); |
129f5643 |
64 | return; |
65 | } |
66 | } |
d8985b7d |
67 | |
68 | sub daemon_detach { |
69 | my ($self, %options) = @_; |
70 | |
71 | return unless $self->is_daemon; # return if parent ... |
72 | |
2ecc2ccb |
73 | $self->_get_options( %options ); |
d8985b7d |
74 | # now we are in the daemon ... |
75 | |
129f5643 |
76 | (POSIX::setsid) # set session id |
d8985b7d |
77 | || confess "Cannot detach from controlling process"; |
78 | |
2ecc2ccb |
79 | unless ( $self->no_double_fork ) { |
d8985b7d |
80 | $SIG{'HUP'} = 'IGNORE'; |
81 | fork && exit; |
82 | } |
83 | |
ea9485d8 |
84 | chdir '/'; # change to root directory |
d8985b7d |
85 | umask 0; # clear the file creation mask |
86 | |
2ecc2ccb |
87 | unless ( $self->dont_close_all_files ) { |
b37fcc5f |
88 | # get the max number of possible file descriptors |
3c0d9597 |
89 | my $openmax = POSIX::sysconf( &POSIX::_SC_OPEN_MAX ); |
90 | $openmax = 64 if !defined($openmax) || $openmax < 0; |
d8985b7d |
91 | |
3c0d9597 |
92 | # close them all |
93 | POSIX::close($_) foreach (0 .. $openmax); |
94 | } |
ea9485d8 |
95 | |
4327fe98 |
96 | # fixup STDIN ... |
97 | |
98 | open(STDIN, "+>/dev/null") |
99 | or confess "Could not redirect STDOUT to /dev/null"; |
100 | |
101 | # fixup STDOUT ... |
d8985b7d |
102 | |
129f5643 |
103 | if (my $stdout_file = $ENV{MX_DAEMON_STDOUT}) { |
d8985b7d |
104 | open STDOUT, ">", $stdout_file |
129f5643 |
105 | or confess "Could not redirect STDOUT to $stdout_file : $!"; |
106 | } |
107 | else { |
4327fe98 |
108 | open(STDOUT, "+>&STDIN") |
109 | or confess "Could not redirect STDOUT to /dev/null"; |
129f5643 |
110 | } |
111 | |
4327fe98 |
112 | # fixup STDERR ... |
113 | |
d8985b7d |
114 | if (my $stderr_file = $ENV{MX_DAEMON_STDERR}) { |
3c0d9597 |
115 | open STDERR, ">", $stderr_file |
d8985b7d |
116 | or confess "Could not redirect STDERR to $stderr_file : $!"; |
129f5643 |
117 | } |
d8985b7d |
118 | else { |
4327fe98 |
119 | open(STDERR, "+>&STDIN") |
120 | or confess "Could not redirect STDERR to /dev/null"; ; |
121 | } |
122 | |
123 | # do a little house cleaning ... |
124 | |
125 | # Avoid 'stdin reopened for output' |
126 | # warning with newer perls |
127 | open( NULL, '/dev/null' ); |
128 | <NULL> if (0); |
129 | |
130 | # return success |
131 | return 1; |
ea9485d8 |
132 | } |
18cc5c89 |
133 | |
134 | sub daemonize { |
d8985b7d |
135 | my ($self, %options) = @_; |
136 | $self->daemon_fork(%options); |
137 | $self->daemon_detach(%options); |
18cc5c89 |
138 | } |
139 | |
140 | 1; |
d8985b7d |
141 | |
18cc5c89 |
142 | __END__ |
143 | |
d8985b7d |
144 | =pod |
18cc5c89 |
145 | |
d8985b7d |
146 | =head1 NAME |
18cc5c89 |
147 | |
d8985b7d |
148 | MooseX::Daemonize::Core - A Role with the core daemonization features |
18cc5c89 |
149 | |
150 | =head1 SYNOPSIS |
d8985b7d |
151 | |
152 | package My::Daemon; |
153 | use Moose; |
4327fe98 |
154 | |
d8985b7d |
155 | with 'MooseX::Daemonize::Core'; |
4327fe98 |
156 | |
d8985b7d |
157 | sub start { |
158 | my $self = shift; |
159 | # daemonize me ... |
160 | $self->daemonize; |
161 | # return from the parent,... |
162 | return unless $self->is_daemon; |
163 | # but continue on in the child (daemon) |
164 | } |
165 | |
18cc5c89 |
166 | =head1 DESCRIPTION |
167 | |
4327fe98 |
168 | This is the basic daemonization Role, it provides a few methods (see |
d8985b7d |
169 | below) and the minimum features needed to properly daemonize your code. |
170 | |
171 | =head2 Important Notes |
129f5643 |
172 | |
d8985b7d |
173 | None of the methods in this role will exit the parent process for you, |
174 | it only forks and detaches your child (daemon) process. It is your |
175 | responsibility to exit the parent process in some way. |
176 | |
4327fe98 |
177 | There is no PID or PID file management in this role, that is your |
178 | responsibility (see some of the other roles in this distro for that). |
129f5643 |
179 | |
18cc5c89 |
180 | =head1 ATTRIBUTES |
181 | |
182 | =over |
183 | |
129f5643 |
184 | =item I<is_daemon (is => rw, isa => Bool)> |
18cc5c89 |
185 | |
d8985b7d |
186 | This attribute is used to signal if we are within the |
187 | daemon process or not. |
18cc5c89 |
188 | |
2ecc2ccb |
189 | =item I<no_double_fork (is => rw, isa => Bool)> |
190 | |
191 | Setting this attribute to true will cause this method to not perform the |
192 | typical double-fork, which is extra added protection from your process |
b37fcc5f |
193 | accidentally acquiring a controlling terminal. More information can be |
2ecc2ccb |
194 | found above, and by Googling "double fork daemonize". |
195 | |
196 | If you the double-fork behavior off, you might want to enable the |
197 | I<ignore_zombies>. |
198 | |
199 | =item I<ignore_zombies (is => rw, isa => Bool)> |
200 | |
201 | Setting this attribute to a true value will result in setting the C<$SIG{CHLD}> |
202 | handler to C<IGNORE>. This tells perl to clean up zombie processes. By |
203 | default, and for the most part you don't I<need> it, only when you turn off |
204 | the double fork behavior (with the I<no_double_fork> attribute) |
205 | do you sometimes want this behavior. |
206 | |
207 | =item I<dont_close_all_files (is => rw, isa => Bool)> |
208 | |
209 | Setting this attribute to true will cause it to skip closing all the |
210 | filehandles. This is useful if you are opening things like sockets |
211 | and such in the pre-fork. |
212 | |
18cc5c89 |
213 | =back |
214 | |
d8985b7d |
215 | =head1 METHODS |
18cc5c89 |
216 | |
217 | =over |
218 | |
2ecc2ccb |
219 | =item B<daemon_fork (?%options)> |
129f5643 |
220 | |
d8985b7d |
221 | This forks off the child process to be daemonized. Just as with |
222 | the built in fork, it returns the child pid to the parent process, |
223 | 0 to the child process. It will also set the is_daemon flag |
129f5643 |
224 | appropriately. |
225 | |
b37fcc5f |
226 | The C<%options> argument remains for backwards compatibility, but |
2ecc2ccb |
227 | it is suggested that you use the attributes listed above instead. |
d8985b7d |
228 | |
2ecc2ccb |
229 | =item B<daemon_detach (?%options)> |
129f5643 |
230 | |
d8985b7d |
231 | This detaches the new child process from the terminal by doing |
232 | the following things. |
129f5643 |
233 | |
b37fcc5f |
234 | The C<%options> argument remains for backwards compatibility, but |
2ecc2ccb |
235 | it is suggested that you use the attributes listed above instead. |
236 | |
129f5643 |
237 | =over 4 |
238 | |
d8985b7d |
239 | =item Becomes a session leader |
18cc5c89 |
240 | |
d8985b7d |
241 | This detaches the program from the controlling terminal, it is |
129f5643 |
242 | accomplished by calling POSIX::setsid. |
18cc5c89 |
243 | |
d8985b7d |
244 | =item Performing the double-fork |
245 | |
246 | See below for information on how to change this part of the process. |
247 | |
129f5643 |
248 | =item Changes the current working directory to "/" |
18cc5c89 |
249 | |
d8985b7d |
250 | This is standard daemon behavior, if you want a different working |
251 | directory then simply change it later in your daemons code. |
18cc5c89 |
252 | |
129f5643 |
253 | =item Clears the file creation mask. |
18cc5c89 |
254 | |
129f5643 |
255 | =item Closes all open file descriptors. |
18cc5c89 |
256 | |
2ecc2ccb |
257 | See the I<dont_close_all_files> attribute for information on how to |
258 | change this part of the process. |
3c0d9597 |
259 | |
129f5643 |
260 | =item Reopen STDERR, STDOUT & STDIN to /dev/null |
18cc5c89 |
261 | |
d8985b7d |
262 | This behavior can be controlled slightly though the MX_DAEMON_STDERR |
129f5643 |
263 | and MX_DAEMON_STDOUT environment variables. It will look for a filename |
264 | in either of these variables and redirect STDOUT and/or STDERR to those |
265 | files. This is useful for debugging and/or testing purposes. |
18cc5c89 |
266 | |
d8985b7d |
267 | B<NOTE> |
268 | |
269 | If called from within the parent process (the is_daemon flag is set to |
270 | false), this method will simply return and do nothing. |
271 | |
2ecc2ccb |
272 | =item B<daemonize (?%options)> |
273 | |
274 | This will simply call C<daemon_fork> followed by C<daemon_detach>. |
d8985b7d |
275 | |
b37fcc5f |
276 | The C<%options> argument remains for backwards compatibility, but |
2ecc2ccb |
277 | it is suggested that you use the attributes listed above instead. |
18cc5c89 |
278 | |
279 | =item meta() |
280 | |
281 | The C<meta()> method from L<Class::MOP::Class> |
282 | |
283 | =back |
284 | |
b3e71e62 |
285 | =back |
286 | |
d8985b7d |
287 | =head1 STUFF YOU SHOULD READ |
288 | |
289 | =over 4 |
290 | |
291 | =item Note about double fork |
292 | |
293 | Taken from L<http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66012> |
4327fe98 |
294 | in a comment entitled I<The second fork _is_ necessary by Jonathan Bartlett>, |
295 | it is not the definitive statement on the issue, but it's clear and well |
d8985b7d |
296 | written enough so I decided to reproduce it here. |
297 | |
298 | The first fork accomplishes two things - allow the shell to return, |
299 | and allow you to do a setsid(). |
300 | |
301 | The setsid() removes yourself from your controlling terminal. You |
302 | see, before, you were still listed as a job of your previous process, |
303 | and therefore the user might accidentally send you a signal. setsid() |
304 | gives you a new session, and removes the existing controlling terminal. |
305 | |
306 | The problem is, you are now a session leader. As a session leader, if |
307 | you open a file descriptor that is a terminal, it will become your |
308 | controlling terminal (oops!). Therefore, the second fork makes you NOT |
309 | be a session leader. Only session leaders can acquire a controlling |
310 | terminal, so you can open up any file you wish without worrying that |
311 | it will make you a controlling terminal. |
312 | |
313 | So - first fork - allow shell to return, and permit you to call setsid() |
314 | |
315 | Second fork - prevent you from accidentally reacquiring a controlling |
316 | terminal. |
317 | |
318 | That said, you don't always want this to be the behavior, so you are |
2ecc2ccb |
319 | free to specify otherwise using the I<no_double_fork> attribute. |
d8985b7d |
320 | |
321 | =item Note about zombies |
322 | |
323 | Doing the double fork (see above) tends to get rid of your zombies since |
4327fe98 |
324 | by the time you have double forked your daemon process is then owned by |
325 | the init process. However, sometimes the double-fork is more than you |
d8985b7d |
326 | really need, and you want to keep your daemon processes a little closer |
327 | to you. In this case you have to watch out for zombies, you can avoid then |
2ecc2ccb |
328 | by just setting the I<ignore_zombies> attribute (see above). |
d8985b7d |
329 | |
330 | =back |
331 | |
332 | =head1 ENVIRONMENT VARIABLES |
333 | |
4327fe98 |
334 | These variables are best just used for debugging and/or testing, but |
335 | not used for actual logging. For that, you should reopen STDOUT/ERR on |
336 | your own. |
d8985b7d |
337 | |
338 | =over 4 |
339 | |
340 | =item B<MX_DAEMON_STDOUT> |
341 | |
342 | A filename to redirect the daemon STDOUT to. |
343 | |
344 | =item B<MX_DAEMON_STDERR> |
345 | |
346 | A filename to redirect the daemon STDERR to. |
347 | |
348 | =back |
349 | |
18cc5c89 |
350 | =head1 DEPENDENCIES |
351 | |
129f5643 |
352 | L<Moose::Role>, L<POSIX> |
18cc5c89 |
353 | |
354 | =head1 INCOMPATIBILITIES |
355 | |
18cc5c89 |
356 | None reported. |
357 | |
18cc5c89 |
358 | =head1 BUGS AND LIMITATIONS |
359 | |
18cc5c89 |
360 | No bugs have been reported. |
361 | |
362 | Please report any bugs or feature requests to |
363 | C<bug-acme-dahut-call@rt.cpan.org>, or through the web interface at |
364 | L<http://rt.cpan.org>. |
365 | |
366 | =head1 SEE ALSO |
367 | |
129f5643 |
368 | L<Proc::Daemon> |
369 | |
d8985b7d |
370 | This code is based B<HEAVILY> on L<Proc::Daemon>, we originally |
129f5643 |
371 | depended on it, but we needed some more flexibility, so instead |
d8985b7d |
372 | we just stole the code. |
18cc5c89 |
373 | |
374 | =head1 AUTHOR |
375 | |
129f5643 |
376 | Stevan Little C<< <stevan.little@iinteractive.com> >> |
18cc5c89 |
377 | |
18cc5c89 |
378 | =head1 LICENCE AND COPYRIGHT |
379 | |
05b96f4d |
380 | Copyright (c) 2007-2011, Chris Prather C<< <perigrin@cpan.org> >>. All rights |
18cc5c89 |
381 | reserved. |
382 | |
129f5643 |
383 | Portions heavily borrowed from L<Proc::Daemon> which is copyright Earl Hood. |
384 | |
18cc5c89 |
385 | This module is free software; you can redistribute it and/or |
386 | modify it under the same terms as Perl itself. See L<perlartistic>. |
387 | |
18cc5c89 |
388 | =head1 DISCLAIMER OF WARRANTY |
389 | |
390 | BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY |
391 | FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN |
392 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES |
393 | PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER |
394 | EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
395 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE |
396 | ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH |
397 | YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL |
398 | NECESSARY SERVICING, REPAIR, OR CORRECTION. |
399 | |
400 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING |
401 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR |
402 | REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE |
403 | LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, |
404 | OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE |
405 | THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING |
406 | RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A |
407 | FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF |
408 | SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF |
409 | SUCH DAMAGES. |
d8985b7d |
410 | |
411 | =cut |