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pbot/PBot/ProcessManager.pm
Pragmatic Software 1a41f9aebb Refactor PBot::Timer into PBot::EventQueue
Make better use of PBot::IRC's select loop
Remove use of SIGALRM
2021-06-21 17:26:24 -07:00

368 lines
11 KiB
Perl

# File: ProcessManager.pm
#
# Purpose: Handles forking and execution of module/subroutine processes.
# Provides commands to list running processes and to kill them.
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
package PBot::ProcessManager;
use parent 'PBot::Class';
use PBot::Imports;
use Time::Duration qw/concise duration/;
use Time::HiRes qw/gettimeofday/;
use Getopt::Long qw/GetOptionsFromArray/;
use POSIX qw/WNOHANG/;
use JSON;
sub initialize {
my ($self, %conf) = @_;
# process manager bot commands
$self->{pbot}->{commands}->register(sub { $self->cmd_ps(@_) }, 'ps', 0);
$self->{pbot}->{commands}->register(sub { $self->cmd_kill(@_) }, 'kill', 1);
# give admin capability group the can-kill capability
$self->{pbot}->{capabilities}->add('admin', 'can-kill', 1);
# hash of currently running bot-invoked processes
$self->{processes} = {};
# automatically reap children processes in background
$SIG{CHLD} = sub {
my $pid; do { $pid = waitpid(-1, WNOHANG); $self->remove_process($pid) if $pid > 0; } while $pid > 0;
};
}
sub cmd_ps {
my ($self, $context) = @_;
my $usage = 'Usage: ps [-atu]; -a show all information; -t show running time; -u show user/channel';
my $getopt_error;
local $SIG{__WARN__} = sub {
$getopt_error = shift;
chomp $getopt_error;
};
Getopt::Long::Configure("bundling");
my ($show_all, $show_user, $show_running_time);
my @opt_args = $self->{pbot}->{interpreter}->split_line($context->{arguments}, strip_quotes => 1);
GetOptionsFromArray(
\@opt_args,
'all|a' => \$show_all,
'user|u' => \$show_user,
'time|t' => \$show_running_time
);
return "$getopt_error; $usage" if defined $getopt_error;
my @processes;
foreach my $pid (sort keys %{$self->{processes}}) {
push @processes, $self->{processes}->{$pid};
}
if (not @processes) {
return "No running processes.";
}
my $result = @processes == 1 ? 'One process: ' : @processes . ' processes: ';
my @entries;
foreach my $process (@processes) {
my $entry = "$process->{pid}: $process->{commands}->[0]";
if ($show_running_time or $show_all) {
my $duration = concise duration (gettimeofday - $process->{process_start});
$entry .= " [$duration]";
}
if ($show_user or $show_all) {
$entry .= " ($process->{nick} in $process->{from})";
}
push @entries, $entry;
}
$result .= join '; ', @entries;
return $result;
}
sub cmd_kill {
my ($self, $context) = @_;
my $usage = 'Usage: kill [-a] [-t <seconds>] [-s <signal>] [pids...]; -a kill all processes; -t <seconds> kill processes running longer than <seconds>; -s send <signal> to processes';
my $getopt_error;
local $SIG{__WARN__} = sub {
$getopt_error = shift;
chomp $getopt_error;
};
Getopt::Long::Configure("bundling");
my ($kill_all, $kill_time, $signal);
my @opt_args = $self->{pbot}->{interpreter}->split_line($context->{arguments}, preserve_escapes => 1, strip_quotes => 1);
GetOptionsFromArray(
\@opt_args,
'all|a' => \$kill_all,
'time|t=i' => \$kill_time,
'signal|s=s' => \$signal,
);
return "$getopt_error; $usage" if defined $getopt_error;
if (not $kill_all and not $kill_time and not @opt_args) {
return "Must specify PIDs to kill unless options -a or -t are provided.";
}
if (defined $signal) {
$signal = uc $signal;
} else {
$signal = 'INT';
}
my @pids;
if (defined $kill_all or defined $kill_time) {
my $now = time;
foreach my $pid (sort keys %{$self->{processes}}) {
my $process = $self->{processes}->{$pid};
next if defined $kill_time and $now - $process->{process_start} < $kill_time;
push @pids, $pid;
}
} else {
foreach my $pid (@opt_args) {
return "No such pid $pid." if not exists $self->{processes}->{$pid};
push @pids, $pid;
}
}
return "No matching process." if not @pids;
my $ret = eval { kill $signal, @pids };
if ($@) {
my $error = $@;
$error =~ s/ at PBot.*//;
return $error;
}
return "[$ret] Sent signal " . $signal . ' to ' . join ', ', @pids;
}
sub add_process {
my ($self, $pid, $context) = @_;
$context->{process_start} = gettimeofday;
$self->{processes}->{$pid} = $context;
$self->{pbot}->{logger}->log("Starting process $pid: $context->{commands}->[0]\n");
}
sub remove_process {
my ($self, $pid) = @_;
if (exists $self->{processes}->{$pid}) {
my $command = $self->{processes}->{$pid}->{commands}->[0];
my $duration = gettimeofday - $self->{processes}->{$pid}->{process_start};
$duration = sprintf "%0.3f", $duration;
$self->{pbot}->{logger}->log("Finished process $pid ($command): duration $duration seconds\n");
delete $self->{processes}->{$pid};
} else {
$self->{pbot}->{logger}->log("Finished process $pid\n");
}
}
sub execute_process {
my ($self, $context, $subref, $timeout) = @_;
$timeout //= 30; # default timeout 30 seconds
# ensure contextual command history list is available for add_process()
if (not exists $context->{commands}) {
$context->{commands} = [$context->{command}];
}
# don't fork again if we're already a forked process
if (defined $context->{pid} and $context->{pid} == 0) {
$subref->($context);
return $context->{result};
}
pipe(my $reader, my $writer);
# fork new process
$context->{pid} = fork;
if (not defined $context->{pid}) {
# fork failed
$self->{pbot}->{logger}->log("Could not fork process: $!\n");
close $reader;
close $writer;
delete $context->{pid};
# groan to let the users know something went wrong
$context->{checkflood} = 1;
$self->{pbot}->{interpreter}->handle_result($context, "/me groans loudly.\n");
return;
}
if ($context->{pid} == 0) {
# child
close $reader;
# flag this instance as child
$self->{pbot}->{child} = 1;
# don't quit the IRC client when the child dies
no warnings;
*PBot::IRC::Connection::DESTROY = sub { return; };
use warnings;
# remove atexit handlers
$self->{pbot}->{atexit}->unregister_all;
# execute the provided subroutine, results are stored in $context
eval {
local $SIG{ALRM} = sub { die "Process `$context->{commands}->[0]` timed-out" };
alarm $timeout;
$subref->($context);
alarm 0;
};
# check for errors
if ($@) {
$context->{result} = $@;
$context->{'timed-out'} = 1 if $context->{result} =~ /^Process .* timed-out at PBot\/ProcessManager/;
$self->{pbot}->{logger}->log("Error executing process: $context->{result}\n");
# strip internal PBot source data for IRC output
$context->{result} =~ s/ at PBot.*$//ms;
$context->{result} =~ s/\s+...propagated at .*$//ms;
}
# print $context to pipe
my $json = encode_json $context;
print $writer "$json\n";
close $writer;
# end child
exit 0;
} else {
# parent
# nothing to write to child
close $writer;
# add process
$self->add_process($context->{pid}, $context);
# add reader handler
$self->{pbot}->{select_handler}->add_reader($reader, sub { $self->process_pipe_reader($context->{pid}, @_) });
# return empty string since reader will handle the output when child is finished
return '';
}
}
sub process_pipe_reader {
my ($self, $pid, $buf) = @_;
# retrieve context object from child
my $context = decode_json $buf or do {
$self->{pbot}->{logger}->log("Failed to decode bad json: [$buf]\n");
return;
};
# context is no longer forked
delete $context->{pid};
# check for output
if (not defined $context->{result} or not length $context->{result}) {
$self->{pbot}->{logger}->log("No result from process.\n");
return if $context->{suppress_no_output};
$context->{result} = "No output.";
}
# don't output unnecessary result if command was referenced within a message
if ($context->{referenced}) {
return if $context->{result} =~ m/(?:no results)/i;
}
# handle code factoid result
if (exists $context->{special} and $context->{special} eq 'code-factoid') {
$context->{result} =~ s/\s+$//g;
if (not length $context->{result}) {
$self->{pbot}->{logger}->log("No text result from code-factoid.\n");
return;
}
$context->{original_keyword} = $context->{root_keyword};
$context->{result} = $self->{pbot}->{factoids}->handle_action($context, $context->{result});
}
# if nick isn't overridden yet, check for a potential nick prefix
# TODO: this stuff should be moved to Interpreter::output_result
if (not $context->{nickprefix}) {
# if add_nick is set on the factoid, set the nick override to the caller's nick
if (exists $context->{special} and $context->{special} ne 'code-factoid'
and $self->{pbot}->{factoids}->{factoids}->exists($context->{channel}, $context->{trigger}, 'add_nick')
and $self->{pbot}->{factoids}->{factoids}->get_data($context->{channel}, $context->{trigger}, 'add_nick') != 0)
{
$context->{nickprefix} = $context->{nick};
$context->{nickprefix_disabled} = 0;
$context->{nickprefix_forced} = 1;
} else {
# extract nick-like thing from process result
if ($context->{result} =~ s/^(\S+): //) {
my $nick = $1;
if (lc $nick eq "usage") {
# put it back on result if it's a usage message
$context->{result} = "$nick: $context->{result}";
} else {
my $present = $self->{pbot}->{nicklist}->is_present($context->{channel}, $nick);
if ($present) {
# nick is present in channel
$context->{nickprefix} = $present;
} else {
# nick not present, put it back on result
$context->{result} = "$nick: $context->{result}";
}
}
}
}
}
# send the result off to the bot to be handled
$context->{checkflood} = 1;
$self->{pbot}->{interpreter}->handle_result($context);
}
1;