如何捕捉 KILL 或 HUP 或用户中止信号？

Question

我有一个在我的 linux 服务器后台运行的脚本，我想捕捉重启之类的信号或任何会杀死该脚本的信号，而是在实际退出之前保存任何重要信息。

我认为我需要捕获的大部分内容是 SIGINT、SIGTERM、SIGHUP、SIGKILL。

如何捕捉任何这些信号并让它执行退出函数，否则继续执行它正在做的任何事情？

伪perl代码：

#!/usr/bin/perl

use stricts;
use warnings;

while (true)
{
    #my happy code is running
    #my happy code will sleep for a few until its breath is back to keep running.
}

#ops I have detected an evil force trying to kill me
#let's call the safe exit.
sub safe_exit() 
{
    # save stuff
    exit(1);
}

伪php代码：

<?php

while (1)
{
    #my happy code is running
    #my happy code will sleep for a few until its breath is back to keep running.
}

#ops I have detected an evil force trying to kill me
#let's call the safe exit.

function safe_exit()
{
    # save stuff
    exit(1);
}
?>

Answer 1

PHP 使用pcntl_signal 来注册一个信号处理程序，所以是这样的：

declare(ticks = 1);

function sig_handler($sig) {
    switch($sig) {
        case SIGINT:
        # one branch for signal...
    }
}

pcntl_signal(SIGINT,  "sig_handler");
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP,  "sig_handler");
# Nothing for SIGKILL as it won't work and trying to will give you a warning.

Answer 2

Perl：

$SIG{$_} = \&safe_exit for qw( INT TERM HUP );

SIGKILL 无法被捕获。它不会发送到进程。

%SIG 记录在perlvar 中。另见perlipc

Answer 3

对于 perl 版本，请参阅 perldoc -q signal -- 基本上，将 $SIG{signal} 设置为子引用。