eaiovnaovbqoebvqoeavibavo Daemon.pod000064400000026724147634427450006506 0ustar00 =head1 NAME Proc::Daemon - Run Perl program(s) as a daemon process. =head1 SYNOPSIS use Proc::Daemon; $daemon = Proc::Daemon->new( work_dir => '/my/daemon/directory', ..... ); $Kid_1_PID = $daemon->Init; unless ( $Kid_1_PID ) { # code executed only by the child ... } $Kid_2_PID = $daemon->Init( { work_dir => '/other/daemon/directory', exec_command => 'perl /home/my_script.pl', } ); $pid = $daemon->Status( ... ); $stopped = $daemon->Kill_Daemon( ... ); =head1 DESCRIPTION This module can be used by a Perl program to initialize itself as a daemon or to execute (C) a system command as daemon. You can also check the status of the daemon (alive or dead) and you can kill the daemon. A daemon is a process that runs in the background with no controlling terminal. Generally servers (like FTP, HTTP and SIP servers) run as daemon processes. Do not make the mistake to think that a daemon is a server. ;-) Proc::Daemon does the following: =over 4 =item 1 The script forks a child. =item 2 The child changes the current working directory to the value of 'work_dir'. =item 3 The child clears the file creation mask. =item 4 The child becomes a session leader, which detaches the program from the controlling terminal. =item 5 The child forks another child (the final daemon process). This prevents the potential of acquiring a controlling terminal at all and detaches the daemon completely from the first parent. =item 6 The second child closes all open file descriptors (unless you define C and/or C). =item 7 The second child opens STDIN, STDOUT and STDERR to the location defined in the constructor (C). =item 8 The second child returns to the calling script, or the program defined in 'exec_command' is executed and the second child never returns. =item 9 The first child transfers the PID of the second child (daemon) to the parent. Additionally the PID of the daemon process can be written into a file if 'pid_file' is defined. Then the first child exits. =item 10 If the parent script is looking for a return value, then the PID(s) of the child/ren will be returned. Otherwise the parent will exit. =back NOTE: Because of the second fork the daemon will not be a session-leader and therefore Signals will not be send to other members of his process group. If you need the functionality of a session-leader you may want to call POSIX::setsid() manually at your daemon. INFO: Since C is not performed the same way on Windows systems as on Linux, this module does not work with Windows. Patches appreciated! =head1 CONSTRUCTOR =over 4 =item new ( %ARGS ) The constructor creates a new Proc::Daemon object based on the hash %ARGS. The following keys from %ARGS are used: =over 8 =item work_dir Defines the path to the working directory of your daemon. Defaults to C. =item setuid Sets the real user identifier (C<< $< >>) and the effective user identifier (C<< $> >>) for the daemon process using C, in case you want to run your daemon under an other user than the parent. Obviously the first user must have the rights to switch to the new user otherwise it will stay the same. It is helpful to define the argument C if you start your script at boot time by init with the superuser, but wants the daemon to run under a normal user account. =item setgid Sets the real group identifier (C<$(>) and the effective group identifier (C<$)>) for the daemon process using C, just like C. As with C, the first user must have the rights to switch to the new group, otherwise the group id will not be changed. =item child_STDIN Defines the path to STDIN for your daemon. Defaults to C. Default Mode is '<' (read). You can define other Mode the same way as you do using Perls C in a two-argument form. =item child_STDOUT Defines the path where the output of your daemon will go. Defaults to C. Default Mode is '+>' (write/read). You can define other Mode the same way as you do using Perls C in a two-argument form. =item child_STDERR Defines the path where the error output of your daemon will go. Defaults to C. Default Mode is '+>' (write/read). You can define other Mode the same way as you do using Perls C in a two-argument form, see example below. =item dont_close_fh If you define it, it must be an arrayref with file handles you want to preserve from the parent into the child (daemon). This may be the case if you have code below a C<__DATA__> token in your script or module called by C or C. dont_close_fh => [ 'main::DATA', 'PackageName::DATA', $my_filehandle, ... ], You can add any kind of file handle to the array (expression in single quotes or a scalar variable), including 'STDIN', 'STDOUT' and 'STDERR'. Logically the path settings from above (C, ...) will be ignored in this case. DISCLAIMER: Using this argument may not detach your daemon fully from the parent! Use it at your own risk. =item dont_close_fd Same function and disclaimer as C, but instead of file handles you write the numeric file descriptors inside the arrayref. =item pid_file Defines the path to a file (owned by the parent user) where the PID of the daemon process will be stored. Defaults to C (= write no file). =item file_umask Defines umask for C, C, C and C files. Defaults to C<066> (other users may not modify or read the files). =item exec_command Scalar or arrayref with system command(s) that will be executed by the daemon via Perls C. In this case the child will never return to the parents process! =back Example: my $daemon = Proc::Daemon->new( work_dir => '/working/daemon/directory', child_STDOUT => '/path/to/daemon/output.file', child_STDERR => '+>>debug.txt', pid_file => 'pid.txt', exec_command => 'perl /home/my_script.pl', # or: # exec_command => [ 'perl /home/my_script.pl', 'perl /home/my_other_script.pl' ], ); In this example: =over 8 =item * the PID of the daemon will be returned to C<$daemon> in the parent process and a pid-file will be created at C. =item * STDOUT will be open with Mode '+>' (write/read) to C and STDERR will be open to C with Mode '+>>' (write/read opened for appending). =item * the script C will be executed by C and run as daemon. Therefore the child process will never return to this parent script. =back =back =head1 METHODS =over 4 =item Init( [ { %ARGS } ] ) Become a daemon. If used for the first time after C, you call C with the object reference to start the daemon. $pid = $daemon->Init(); If you want to use the object reference created by C for other daemons, you write C. %ARGS are the same as described in C. Notice that you shouldn't call C without argument in this case, or the next daemon will execute and/or write in the same files as the first daemon. To prevent this use at least an empty anonymous hash here. $pid = $daemon->Init( {} ); @pid = $daemon->Init( { work_dir => '/other/daemon/directory', exec_command => [ 'perl /home/my_second_script.pl', 'perl /home/my_third_script.pl' ], } ); If you don't need the Proc::Daemon object reference in your script, you can also use the method without object reference: $pid = Proc::Daemon::Init(); # or $pid = Proc::Daemon::Init( { %ARGS } ); C returns the PID (scalar) of the daemon to the parent, or the PIDs (array) of the daemons created if C has more then one program to execute. See examples above. C returns 0 to the child (daemon). If you call the C method in the context without looking for a return value (void context) the parent process will C here like in earlier versions: Proc::Daemon::Init(); =item Status( [ $ARG ] ) This function checks the status of the process (daemon). Returns the PID number (alive) or 0 (dead). $ARG can be a string with: =over 8 =item * C, in this case it tries to get the PID to check out of the object reference settings. =item * a PID number to check. =item * the path to a file containing the PID to check. =item * the command line entry of the running program to check. This requires L to be installed. =back =item Kill_Daemon( [ $ARG [, SIGNAL] ] ) This function kills the Daemon process. Returns the number of processes successfully killed (which mostly is not the same as the PID number), or 0 if the process wasn't found. $ARG is the same as of C. SIGNAL is an optional signal name or number as required by Perls C function and listed out by C on your system. Default value is 9 ('KILL' = non-catchable, non-ignorable kill). =item Fork Is like the Perl built-in C, but it retries to fork over 30 seconds if necessary and if possible to fork at all. It returns the child PID to the parent process and 0 to the child process. If the fork is unsuccessful it Cs and returns C. =back =head1 OTHER METHODS Proc::Daemon also defines some other functions. See source code for more details: =over 4 =item OpenMax( [ $NUMBER ] ) Returns the maximum file descriptor number. If undetermined $NUMBER will be returned. =item adjust_settings Does some fixes/adjustments on the C settings together with C. =item fix_filename( $KEYNAME ) Prevents double use of same filename in different processes. =item get_pid( [ $STRING ] ) Returns the wanted PID if it can be found. =item get_pid_by_proc_table_attr( $ATTR, $MATCH ) Returns the wanted PID by looking into the process table, or C. Requires the C module to be installed. =back =head1 NOTES C is still available for backwards capability. Proc::Daemon is now taint safe (assuming it is not passed any tainted parameters). =head1 AUTHORS Primary-maintainer and code writer until version 0.03: =over 4 =item * Earl Hood, earl@earlhood.com, http://www.earlhood.com/ =back Co-maintainer and code writer since version 0.04 until version 0.14: =over 4 =item * Detlef Pilzecker, http://search.cpan.org/~deti/, http://www.secure-sip-server.net/ =back Co-maintainer and code writer since version 0.15: =over 4 =item * Pavel Denisov, http://search.cpan.org/~akreal/ =back =head1 CREDITS Initial implementation of C derived from the following sources: =over 4 =item * "Advanced Programming in the UNIX Environment" by W. Richard Stevens. Addison-Wesley, Copyright 1992. =item * "UNIX Network Programming", Vol 1, by W. Richard Stevens. Prentice-Hall PTR, Copyright 1998. =back =head1 PREREQUISITES This module requires the C module to be installed. The C module is not essentially required but it can be useful if it is installed (see above). =head1 REPOSITORY L =head1 SEE ALSO L, L, L =head1 COPYRIGHT This module is Copyright (C) 1997-2015 by Earl Hood, Detlef Pilzecker and Pavel Denisov. All Rights Reserved. This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself. PID/File.pm000064400000026711147634427450006424 0ustar00# # Proc::PID::File - pidfile manager # Copyright (C) 2001-2003 Erick Calder # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # package Proc::PID::File; =head1 NAME Proc::PID::File - a module to manage process id files =head1 SYNOPSIS use Proc::PID::File; die "Already running!" if Proc::PID::File->running(); Process that spawn child processes may want to protect each separately by using multiple I. my $child1 = Proc::PID::File->new(name => "lock.1"); my $child2 = Proc::PID::File->new(name => "lock.2"); which may be checked like this: if $child1->alive(); and should be released manually: $child1->release(); =head1 DESCRIPTION This Perl module is useful for writers of daemons and other processes that need to tell whether they are already running, in order to prevent multiple process instances. The module accomplishes this via *nix-style I, which are files that store a process identifier. The module provides two interfaces: 1) a simple call, and 2) an object-oriented interface =cut require Exporter; @ISA = qw(Exporter); use strict; use vars qw($VERSION $RPM_Requires); use Fcntl qw(:DEFAULT :flock); $VERSION = "1.27"; $RPM_Requires = "procps"; my $RUNDIR = "/var/run"; my ($ME) = $0 =~ m|([^/]+)$|; my $self; # -- Simple Interface -------------------------------------------------------- =head1 Simple Interface The simple interface consists of a call as indicated in the first example of the B section above. This approach avoids causing race conditions whereby one instance of a daemon could read the I after a previous instance has read it but before it has had a chance to write to it. =head2 running [hash[-ref]] The parameter signature for this function is identical to that of the I<-Enew()> method described below in the B section of this document. The method's return value is the same as that of I<-Ealive()>. =cut sub running { $self = shift->new(@_); local *FH; my $pid = $self->read(*FH); if ($pid && $pid != $$ && kill(0, $pid)) { $self->debug("running: $pid"); close FH; return $self->verify($pid) ? $pid : 0; } $self->write(*FH); return 0; } # -- Object oriented Interface ----------------------------------------------- =head1 OO Interface The following methods are provided: =head2 new [hash[-ref]] This method is used to create an instance object. It automatically calls the I<-Efile()> method described below and receives the same paramters. For a listing of valid keys in this hash please refer to the aforementioned method documentation below. In addition to the above, the following constitute valid keys: =over =item I = 1 | string This parameter implements the second solution outlined in the WARNING section of this document and is used to verify that an existing I correctly represents a live process other than the current. If set to a string, it will be interpreted as a I and used to search within the name of the running process. Alternatively, a 1 may be passed: For Linux/FreeBSD, this indicates that the value of I<$0> will be used (stripped of its full path); for Cygwin, I<$^X> (stripped of path and extension) will be used. If the parameter is not passed, no verification will take place. Please note that verification will only work for the operating systems listed below and that the OS will be auto-sensed. See also DEPENDENCIES section below. Supported platforms: Linux, FreeBSD, Cygwin =item I Any non-zero value turns debugging output on. Additionally, if a string is passed containing the character B, the module name will be prefixed to the debugging output. =back =cut sub new { my $class = shift; my $self = bless({}, $class); %$self = &args; $self->file(); # init file path $self->{debug} ||= ""; return $self; } =head2 file [hash[-ref]] Use this method to set the path of the I. The method receives an optional hash (or hash reference) with the keys listed below, from which it makes a path of the format: F<$dir/$name.pid>. =over =item I Specifies the directory to place the pid file. If left unspecified, defaults to F. =item I Indicates the name of the current process. When not specified, defaults to I. =back =cut sub file { my $self = shift; %$self = (%$self, &args); $self->{dir} ||= $RUNDIR; $self->{name} ||= $ME; $self->{path} = sprintf("%s/%s.pid", $self->{dir}, $self->{name}); } =head2 alive Returns true when the process is already running. Please note that this call must be made *after* daemonisation i.e. subsequent to the call to fork(). If the B flag was set during the instance creation, the process id is verified, alternatively the flag may be passed directly to this method. =cut sub alive { my $self = shift; my %args = &args; $self->{verify} = $args{verify} if $args{verify}; my $pid = $self->read() || ""; $self->debug("alive(): $pid"); if ($pid && $pid != $$ && kill(0, $pid)) { return $self->verify($pid) ? $pid : 0; } return 0; } =head2 touch Causes for the current process id to be written to the I. =cut sub touch { shift->write(); } =head2 release This method is used to delete the I and is automatically called by DESTROY method. It should thus be unnecessary to call it directly. =cut sub release { my $self = shift; $self->debug("release()"); unlink($self->{path}) || warn $!; } =head2 locktime [hash[-ref]] This method returns the I of the I. =cut sub locktime { my $self = shift; return (stat($self->{path}))[10]; } # -- support functionality --------------------------------------------------- sub verify { my ($self, $pid) = @_; return 1 unless $self->{verify}; my $ret = 0; $self->debug("verify(): OS = $^O"); if ($^O =~ /linux|freebsd|cygwin/i) { my $me = $self->{verify}; if (!$me || $me eq "1") { $me = $ME; if ($^O eq "cygwin") { $^X =~ m|([^/]+)$|; ($me = $1) =~ s/\.exe$//; } } my $cols = delete($ENV{'COLUMNS'}); # prevents `ps` from wrapping my @ps = split m|$/|, qx/ps -fp $pid/ || die "ps utility not available: $!"; s/^\s+// for @ps; # leading spaces confuse us $ENV{'COLUMNS'} = $cols if defined($cols); no warnings; # hate that deprecated @_ thing my $n = split(/\s+/, $ps[0]); @ps = split /\s+/, $ps[1], $n; $ret = $ps[$n - 1] =~ /\Q$me\E/;; } $self->debug(" - ret: [$ret]"); $ret; } # Returns the process id currently stored in the file set. If the method # is passed a file handle, it will return the value, leaving the file handle # locked. This is useful for atomic operations where the caller needs to # write to the file after the read without allowing other dirty writes. # # Please note, when passing a file handle, caller is responsible for # closing it. Also, file handles must be passed by reference! sub read { my ($self, $fh) = @_; sysopen $fh, $self->{path}, O_RDWR|O_CREAT || die qq/Cannot open pid file "$self->{path}": $!\n/; flock($fh, LOCK_EX | LOCK_NB) || die qq/pid "$self->{path}" already locked: $!\n/; my ($pid) = <$fh> =~ /^(\d+)/; close $fh if @_ == 1; $self->debug("read(\"$self->{path}\") = " . ($pid || "")); return $pid; } # Causes for the current process id to be written to the selected # file. If a file handle it passed, the method assumes it has already # been opened, otherwise it opens its own. Please note that file # handles must be passed by reference! sub write { my ($self, $fh) = @_; $self->debug("write($$)"); if (@_ == 1) { sysopen $fh, $self->{path}, O_RDWR|O_CREAT || die qq/Cannot open pid file "$self->{path}": $!\n/; flock($fh, LOCK_EX | LOCK_NB) || die qq/pid "$self->{path}" already locked: $!\n/; } sysseek $fh, 0, 0; truncate $fh, 0; syswrite $fh, "$$\n", length("$$\n"); close $fh || die qq/Cannot write pid file "$self->{path}": $!\n/; } sub args { !defined($_[0]) ? () : ref($_[0]) ? %{$_[0]} : @_; } sub debug { my $self = shift; my $msg = shift || $_; $msg = "> Proc::PID::File - $msg" if $self->{debug} =~ /M/; # prefix with module name print $msg if $self->{debug}; } sub DESTROY { my $self = shift; if (exists($INC{'threads.pm'})) { return if threads->tid() != 0; } my $pid = $self->read(); $self->release() if $self->{path} && $pid && $pid == $$; } 1; __END__ # -- documentation ----------------------------------------------------------- =head1 AUTHOR Erick Calder =head1 ACKNOWLEDGEMENTS 1k thx to Steven Haryanto whose package (Proc::RID_File) inspired this implementation. Our gratitude also to Alan Ferrency for fingering the boot-up problem and suggesting possible solutions. =head1 DEPENDENCIES For Linux, FreeBSD and Cygwin, support of the I option requires availability of the B utility. For Linux/FreeBSD This is typically found in the B package. Cygwin users need to run version 1.5.20 or later for this to work. =head1 WARNING This module may prevent daemons from starting at system boot time. The problem occurs because the process id written to the I by an instance of the daemon may coincidentally be reused by another process after a system restart, thus making the daemon think it's already running. Some ideas on how to fix this problem are catalogued below, but unfortunately, no platform-independent solutions have yet been gleaned. =over =item - leaving the I open for the duration of the daemon's life =item - checking a C to make sure the pid is what one expects (current implementation) =item - looking at /proc/$PID/stat for a process name =item - check mtime of the pidfile versus uptime; don't trust old pidfiles =item - try to get the script to nuke its pidfile when it exits (this is vulnerable to hardware resets and hard reboots) =item - try to nuke the pidfile at boot time before the script runs; this solution suffers from a race condition wherein two instances read the I before one manages to lock it, thus allowing two instances to run simultaneously. =back =head1 SUPPORT For help and thank you notes, e-mail the author directly. To report a bug, submit a patch or add to our wishlist please visit the CPAN bug manager at: F =head1 AVAILABILITY The latest version of the tarball, RPM and SRPM may always be found at: F Additionally the module is available from CPAN. =head1 LICENCE This utility is free and distributed under GPL, the Gnu Public License. A copy of this license was included in a file called LICENSE. If for some reason, this file was not included, please see F to obtain a copy of this license. $Id: File.pm,v 1.16 2004-04-08 02:27:25 ekkis Exp $ Daemon.pm000064400000063234147634427450006335 0ustar00################################################################################ ## File: ## Daemon.pm ## Authors: ## Earl Hood earl@earlhood.com ## Detlef Pilzecker deti@cpan.org ## Pavel Denisov akreal@cpan.org ## Description: ## Run Perl program(s) as a daemon process, see docs in the Daemon.pod file ################################################################################ ## Copyright (C) 1997-2015 by Earl Hood, Detlef Pilzecker and Pavel Denisov. ## ## All rights reserved. ## ## This module is free software. It may be used, redistributed and/or modified ## under the same terms as Perl itself. ################################################################################ package Proc::Daemon; use strict; use POSIX(); $Proc::Daemon::VERSION = '0.19'; ################################################################################ # Create the Daemon object: # my $daemon = Proc::Daemon->new( [ %Daemon_Settings ] ) # # %Daemon_Settings are hash key=>values and can be: # work_dir => '/working/daemon/directory' -> defaults to '/' # setgid => 12345 -> defaults to # setuid => 12345 -> defaults to # child_STDIN => '/path/to/daemon/STDIN.file' -> defautls to ' '/path/to/daemon/STDOUT.file' -> defaults to '+>/dev/null' # child_STDERR => '/path/to/daemon/STDERR.file' -> defaults to '+>/dev/null' # dont_close_fh => [ 'main::DATA', 'PackageName::DATA', 'STDOUT', ... ] # -> arrayref with file handles you do not want to be closed in the daemon. # dont_close_fd => [ 5, 8, ... ] -> arrayref with file # descriptors you do not want to be closed in the daemon. # pid_file => '/path/to/pid/file.txt' -> defaults to # undef (= write no file). # file_umask => 022 -> defaults to 066 # exec_command => 'perl /home/script.pl' -> execute a system command # via Perls *exec PROGRAM* at the end of the Init routine and never return. # Must be an arrayref if you want to create several daemons at once. # # Returns: the blessed object. ################################################################################ sub new { my ( $class, %args ) = @_; my $self = \%args; bless( $self, $class ); $self->{memory} = {}; return $self; } ################################################################################ # Become a daemon: # $daemon->Init # # or, for more daemons with other settings in the same script: # Use a hash as below. The argument must (!) now be a hashref: {...} # even if you don't modify the initial settings (=> use empty hashref). # $daemon->Init( { [ %Daemon_Settings ] } ) # # or, if no Daemon->new() object was created and for backward compatibility: # Proc::Daemon::Init( [ { %Daemon_Settings } ] ) # In this case the argument must be or a hashref! # # %Daemon_Settings see &new. # # Returns to the parent: # - nothing (parent does exit) if the context is looking for no return value. # - the PID(s) of the daemon(s) created. # Returns to the child (daemon): # its PID (= 0) | never returns if used with 'exec_command'. ################################################################################ sub Init { my Proc::Daemon $self = shift; my $settings_ref = shift; # Check if $self has been blessed into the package, otherwise do it now. unless ( ref( $self ) && eval{ $self->isa( 'Proc::Daemon' ) } ) { $self = ref( $self ) eq 'HASH' ? Proc::Daemon->new( %$self ) : Proc::Daemon->new(); } # If $daemon->Init is used again in the same script, # update to the new arguments. elsif ( ref( $settings_ref ) eq 'HASH' ) { map { $self->{ $_ } = $$settings_ref{ $_ } } keys %$settings_ref; } # Open a filehandle to an anonymous temporary pid file. If this is not # possible (some environments do not allow all users to use anonymous # temporary files), use the pid_file(s) to retrieve the PIDs for the parent. my $FH_MEMORY; unless ( open( $FH_MEMORY, "+>", undef ) || $self->{pid_file} ) { die "Can not anonymous temporary pidfile ('$!'), therefore you must add 'pid_file' as an Init() argument, e.g. to: '/tmp/proc_daemon_pids'"; } # Get the file descriptors the user does not want to close. my %dont_close_fd; if ( defined $self->{dont_close_fd} ) { die "The argument 'dont_close_fd' must be arrayref!" if ref( $self->{dont_close_fd} ) ne 'ARRAY'; foreach ( @{ $self->{dont_close_fd} } ) { die "All entries in 'dont_close_fd' must be numeric ('$_')!" if $_ =~ /\D/; $dont_close_fd{ $_ } = 1; } } # Get the file descriptors of the handles the user does not want to close. if ( defined $self->{dont_close_fh} ) { die "The argument 'dont_close_fh' must be arrayref!" if ref( $self->{dont_close_fh} ) ne 'ARRAY'; foreach ( @{ $self->{dont_close_fh} } ) { if ( defined ( my $fn = fileno $_ ) ) { $dont_close_fd{ $fn } = 1; } } } # If system commands are to be executed, put them in a list. my @exec_command = ref( $self->{exec_command} ) eq 'ARRAY' ? @{ $self->{exec_command} } : ( $self->{exec_command} ); $#exec_command = 0 if $#exec_command < 0; # Create a daemon for every system command. foreach my $exec_command ( @exec_command ) { # The first parent is running here. # Using this subroutine or loop multiple times we must modify the filenames: # 'child_STDIN', 'child_STDOUT', 'child_STDERR' and 'pid_file' for every # daemon (a higher number will be appended to the filenames). $self->adjust_settings(); # First fork. my $pid = Fork(); if ( defined $pid && $pid == 0 ) { # The first child runs here. # Set the new working directory. die "Can't to $self->{work_dir}: $!" unless chdir $self->{work_dir}; # Set the file creation mask. $self->{_orig_umask} = umask; umask($self->{file_umask}); # Detach the child from the terminal (no controlling tty), make it the # session-leader and the process-group-leader of a new process group. die "Cannot detach from controlling terminal" if POSIX::setsid() < 0; # "Is ignoring SIGHUP necessary? # # It's often suggested that the SIGHUP signal should be ignored before # the second fork to avoid premature termination of the process. The # reason is that when the first child terminates, all processes, e.g. # the second child, in the orphaned group will be sent a SIGHUP. # # 'However, as part of the session management system, there are exactly # two cases where SIGHUP is sent on the death of a process: # # 1) When the process that dies is the session leader of a session that # is attached to a terminal device, SIGHUP is sent to all processes # in the foreground process group of that terminal device. # 2) When the death of a process causes a process group to become # orphaned, and one or more processes in the orphaned group are # stopped, then SIGHUP and SIGCONT are sent to all members of the # orphaned group.' [2] # # The first case can be ignored since the child is guaranteed not to have # a controlling terminal. The second case isn't so easy to dismiss. # The process group is orphaned when the first child terminates and # POSIX.1 requires that every STOPPED process in an orphaned process # group be sent a SIGHUP signal followed by a SIGCONT signal. Since the # second child is not STOPPED though, we can safely forego ignoring the # SIGHUP signal. In any case, there are no ill-effects if it is ignored." # Source: http://code.activestate.com/recipes/278731/ # # local $SIG{'HUP'} = 'IGNORE'; # Second fork. # This second fork is not absolutely necessary, it is more a precaution. # 1. Prevent possibility of reacquiring a controlling terminal. # Without this fork the daemon would remain a session-leader. In # this case there is a potential possibility that the process could # reacquire a controlling terminal. E.g. if it opens a terminal device, # without using the O_NOCTTY flag. In Perl this is normally the case # when you use on this kind of device, instead of # with the O_NOCTTY flag set. # Note: Because of the second fork the daemon will not be a session- # leader and therefore Signals will not be send to other members of # his process group. If you need the functionality of a session-leader # you may want to call POSIX::setsid() manually on your daemon. # 2. Detach the daemon completely from the parent. # The double-fork prevents the daemon from becoming a zombie. It is # needed in this module because the grandparent process can continue. # Without the second fork and if a child exits before the parent # and you forget to call in the parent you will get a zombie # until the parent also terminates. Using the second fork we can be # sure that the parent of the daemon is finished near by or before # the daemon exits. $pid = Fork(); if ( defined $pid && $pid == 0 ) { # Here the second child is running. # Close all file handles and descriptors the user does not want # to preserve. my $hc_fd; # highest closed file descriptor close $FH_MEMORY; foreach ( 0 .. OpenMax() ) { unless ( $dont_close_fd{ $_ } ) { if ( $_ == 0 ) { close STDIN } elsif ( $_ == 1 ) { close STDOUT } elsif ( $_ == 2 ) { close STDERR } else { $hc_fd = $_ if POSIX::close( $_ ) } } } # Sets the real group identifier and the effective group # identifier for the daemon process before opening files. # Must set group first because you cannot change group # once you have changed user POSIX::setgid( $self->{setgid} ) if defined $self->{setgid}; # Sets the real user identifier and the effective user # identifier for the daemon process before opening files. POSIX::setuid( $self->{setuid} ) if defined $self->{setuid}; # Reopen STDIN, STDOUT and STDERR to 'child_STD...'-path or to # /dev/null. Data written on a null special file is discarded. # Reads from the null special file always return end of file. open( STDIN, $self->{child_STDIN} || "{child_STDOUT} || "+>/dev/null" ) unless $dont_close_fd{ 1 }; open( STDERR, $self->{child_STDERR} || "+>/dev/null" ) unless $dont_close_fd{ 2 }; # Since is in some cases "secretly" closing # file descriptors without telling it to perl, we need to # re and as many files as we closed with # . Otherwise it can happen (especially with # FH opened by __DATA__ or __END__) that there will be two perl # handles associated with one file, what can cause some # confusion. :-) # see: http://rt.perl.org/rt3/Ticket/Display.html?id=72526 if ( $hc_fd ) { my @fh; foreach ( 3 .. $hc_fd ) { open $fh[ $_ ], "{_orig_umask}; # Execute a system command and never return. if ( $exec_command ) { exec ($exec_command) or die "couldn't exec $exec_command: $!"; exit; # Not a real exit, but needed since Perl warns you if # there is no statement like , , or # following . The function executes a system # command and never returns. } # Return the childs own PID (= 0) return $pid; } # First child (= second parent) runs here. # Print the PID of the second child into ... $pid ||= ''; # ... the anonymous temporary pid file. if ( $FH_MEMORY ) { print $FH_MEMORY "$pid\n"; close $FH_MEMORY; } # ... the real 'pid_file'. if ( $self->{pid_file} ) { open( my $FH_PIDFILE, "+>", $self->{pid_file} ) || die "Can not open pidfile (pid_file => '$self->{pid_file}'): $!"; print $FH_PIDFILE $pid; close $FH_PIDFILE; } # Don't for the second child to exit, # even if we don't have a value in $exec_command. # The second child will become orphan by here, but then it # will be adopted by init(8), which automatically performs a # to remove the zombie when the child exits. POSIX::_exit(0); } # Only first parent runs here. # A child that terminates, but has not been waited for becomes # a zombie. So we wait for the first child to exit. waitpid( $pid, 0 ); } # Only first parent runs here. # Exit if the context is looking for no value (void context). exit 0 unless defined wantarray; # Get the daemon PIDs out of the anonymous temporary pid file # or out of the real pid-file(s) my @pid; if ( $FH_MEMORY ) { seek( $FH_MEMORY, 0, 0 ); @pid = map { chomp $_; $_ eq '' ? undef : $_ } <$FH_MEMORY>; $_ = (/^(\d+)$/)[0] foreach @pid; # untaint close $FH_MEMORY; } elsif ( $self->{memory}{pid_file} ) { foreach ( keys %{ $self->{memory}{pid_file} } ) { open( $FH_MEMORY, "<", $_ ) || die "Can not open pid_file '<$_': $!"; push( @pid, <$FH_MEMORY> ); close $FH_MEMORY; } } # Return the daemon PIDs (from second child/ren) to the first parent. return ( wantarray ? @pid : $pid[0] ); } # For backward capability: *init = \&Init; ################################################################################ # Set some defaults and adjust some settings. # Args: ( $self ) # Returns: nothing ################################################################################ sub adjust_settings { my Proc::Daemon $self = shift; # Set default 'work_dir' if needed. $self->{work_dir} ||= '/'; $self->fix_filename( 'child_STDIN', 1 ) if $self->{child_STDIN}; $self->fix_filename( 'child_STDOUT', 1 ) if $self->{child_STDOUT}; $self->fix_filename( 'child_STDERR', 1 ) if $self->{child_STDERR}; # Check 'pid_file's name if ( $self->{pid_file} ) { die "Pidfile (pid_file => '$self->{pid_file}') can not be only a number. I must be able to distinguish it from a PID number in &get_pid('...')." if $self->{pid_file} =~ /^\d+$/; $self->fix_filename( 'pid_file' ); } $self->{file_umask} ||= 066; return; } ################################################################################ # - If the keys value is only a filename add the path of 'work_dir'. # - If we have already set a file for this key with the same "path/name", # add a number to the file. # Args: ( $self, $key, $extract_mode ) # key: one of 'child_STDIN', 'child_STDOUT', 'child_STDERR', 'pid_file' # extract_mode: true = separate MODE form filename before checking # path/filename; false = no MODE to check # Returns: nothing ################################################################################ sub fix_filename { my Proc::Daemon $self = shift; my $key = shift; my $var = $self->{ $key }; my $mode = ( shift ) ? ( $var =~ s/^([\+\<\>\-\|]+)// ? $1 : ( $key eq 'child_STDIN' ? '<' : '+>' ) ) : ''; # add path to filename if ( $var =~ s/^\.\/// || $var !~ /\// ) { $var = $self->{work_dir} =~ /\/$/ ? $self->{work_dir} . $var : $self->{work_dir} . '/' . $var; } # If the file was already in use, modify it with '_number': # filename_X | filename_X.ext if ( $self->{memory}{ $key }{ $var } ) { $var =~ s/([^\/]+)$//; my @i = split( /\./, $1 ); my $j = $#i ? $#i - 1 : 0; $self->{memory}{ "$key\_num" } ||= 0; $i[ $j ] =~ s/_$self->{memory}{ "$key\_num" }$//; $self->{memory}{ "$key\_num" }++; $i[ $j ] .= '_' . $self->{memory}{ "$key\_num" }; $var .= join( '.', @i ); } $self->{memory}{ $key }{ $var } = 1; $self->{ $key } = $mode . $var; return; } ################################################################################ # Fork(): Retries to fork over 30 seconds if possible to fork at all and # if necessary. # Returns the child PID to the parent process and 0 to the child process. # If the fork is unsuccessful it Cs and returns C. ################################################################################ sub Fork { my $pid; my $loop = 0; FORK: { if ( defined( $pid = fork ) ) { return $pid; } # EAGAIN - fork cannot allocate sufficient memory to copy the parent's # page tables and allocate a task structure for the child. # ENOMEM - fork failed to allocate the necessary kernel structures # because memory is tight. # Last the loop after 30 seconds if ( $loop < 6 && ( $! == POSIX::EAGAIN() || $! == POSIX::ENOMEM() ) ) { $loop++; sleep 5; redo FORK; } } warn "Can't fork: $!"; return undef; } ################################################################################ # OpenMax( [ NUMBER ] ) # Returns the maximum number of possible file descriptors. If sysconf() # does not give me a valid value, I return NUMBER (default is 64). ################################################################################ sub OpenMax { my $openmax = POSIX::sysconf( &POSIX::_SC_OPEN_MAX ); return ( ! defined( $openmax ) || $openmax < 0 ) ? ( shift || 64 ) : $openmax; } ################################################################################ # Check if the (daemon) process is alive: # Status( [ number or string ] ) # # Examples: # $object->Status() - Tries to get the PID out of the settings in new() and checks it. # $object->Status( 12345 ) - Number of PID to check. # $object->Status( './pid.txt' ) - Path to file containing one PID to check. # $object->Status( 'perl /home/my_perl_daemon.pl' ) - Command line entry of the # running program to check. Requires Proc::ProcessTable to work. # # Returns the PID (alive) or 0 (dead). ################################################################################ sub Status { my Proc::Daemon $self = shift; my $pid = shift; # Get the process ID. ( $pid, undef ) = $self->get_pid( $pid ); # Return if no PID was found. return 0 if ! $pid; # The kill(2) system call will check whether it's possible to send # a signal to the pid (that means, to be brief, that the process # is owned by the same user, or we are the super-user). This is a # useful way to check that a child process is alive (even if only # as a zombie) and hasn't changed its UID. return ( kill( 0, $pid ) ? $pid : 0 ); } ################################################################################ # Kill the (daemon) process: # Kill_Daemon( [ number or string [, SIGNAL ] ] ) # # Examples: # $object->Kill_Daemon() - Tries to get the PID out of the settings in new() and kill it. # $object->Kill_Daemon( 12345, 'TERM' ) - Number of PID to kill with signal 'TERM'. The # names or numbers of the signals are the ones listed out by kill -l on your system. # $object->Kill_Daemon( './pid.txt' ) - Path to file containing one PID to kill. # $object->Kill_Daemon( 'perl /home/my_perl_daemon.pl' ) - Command line entry of the # running program to kill. Requires Proc::ProcessTable to work. # # Returns the number of processes successfully killed, # which mostly is not the same as the PID number. ################################################################################ sub Kill_Daemon { my Proc::Daemon $self = shift; my $pid = shift; my $signal = shift || 'KILL'; my $pidfile; # Get the process ID. ( $pid, $pidfile ) = $self->get_pid( $pid ); # Return if no PID was found. return 0 if ! $pid; # Kill the process. my $killed = kill( $signal, $pid ); if ( $killed && $pidfile ) { # Set PID in pid file to '0'. if ( open( my $FH_PIDFILE, "+>", $pidfile ) ) { print $FH_PIDFILE '0'; close $FH_PIDFILE; } else { warn "Can not open pidfile (pid_file => '$pidfile'): $!" } } return $killed; } ################################################################################ # Return the PID of a process: # get_pid( number or string ) # # Examples: # $object->get_pid() - Tries to get the PID out of the settings in new(). # $object->get_pid( 12345 ) - Number of PID to return. # $object->get_pid( './pid.txt' ) - Path to file containing the PID. # $object->get_pid( 'perl /home/my_perl_daemon.pl' ) - Command line entry of # the running program. Requires Proc::ProcessTable to work. # # Returns an array with ( 'the PID | ', 'the pid_file | ' ) ################################################################################ sub get_pid { my Proc::Daemon $self = shift; my $string = shift || ''; my ( $pid, $pidfile ); if ( $string ) { # $string is already a PID. if ( $string =~ /^(\d+)$/ ) { $pid = $1; # untaint } # Open the pidfile and get the PID from it. elsif ( open( my $FH_MEMORY, "<", $string ) ) { $pid = <$FH_MEMORY>; close $FH_MEMORY; die "I found no valid PID ('$pid') in the pidfile: '$string'" if $pid =~ /\D/s; $pid = ($pid =~ /^(\d+)$/)[0]; # untaint $pidfile = $string; } # Get the PID by the system process table. else { $pid = $self->get_pid_by_proc_table_attr( 'cmndline', $string ); } } # Try to get the PID out of the new() settings. if ( ! $pid ) { # Try to get the PID out of the 'pid_file' setting. if ( $self->{pid_file} && open( my $FH_MEMORY, "<", $self->{pid_file} ) ) { $pid = <$FH_MEMORY>; close $FH_MEMORY; if ($pid && $pid =~ /^(\d+)$/) { $pid = $1; # untaint $pidfile = $self->{pid_file}; } else { $pid = undef; } } # Try to get the PID out of the system process # table by the 'exec_command' setting. if ( ! $pid && $self->{exec_command} ) { $pid = $self->get_pid_by_proc_table_attr( 'cmndline', $self->{exec_command} ); } } return ( $pid, $pidfile ); } ################################################################################ # This sub requires the Proc::ProcessTable module to be installed!!! # # Search for the PID of a process in the process table: # $object->get_pid_by_proc_table_attr( 'unix_process_table_attribute', 'string that must match' ) # # unix_process_table_attribute examples: # For more see the README.... files at http://search.cpan.org/~durist/Proc-ProcessTable/ # uid - UID of process # pid - process ID # ppid - parent process ID # fname - file name # state - state of process # cmndline - full command line of process # cwd - current directory of process # # Example: # get_pid_by_proc_table_attr( 'cmndline', 'perl /home/my_perl_daemon.pl' ) # # Returns the process PID on success, otherwise . ################################################################################ sub get_pid_by_proc_table_attr { my Proc::Daemon $self = shift; my ( $command, $match ) = @_; my $pid; # eval - Module may not be installed eval { require Proc::ProcessTable; my $table = Proc::ProcessTable->new()->table; foreach ( @$table ) { # fix for Proc::ProcessTable: under some conditions $_->cmndline # returns with space and/or other characters at the end next unless $_->$command =~ /^$match\s*$/; $pid = $_->pid; last; } }; warn "- Problem in get_pid_by_proc_table_attr( '$command', '$match' ):\n $@ You may not use a command line entry to get the PID of your process.\n This function requires Proc::ProcessTable (http://search.cpan.org/~durist/Proc-ProcessTable/) to work.\n" if $@; return $pid; } 1;