关于centos：由cron运行时，启动守护程序的Perlpackage器离开僵尸


Perl wrapper to start daemon leaves zombie when run by cron

我有一个Perl脚本来作为守护进程启动进程。但是，当我从cron调用它时，我已经退出了进程。我已经将其简化为一个最小的脚本，我正在将\\'tail \\'作为守护程序的占位符开始：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
use POSIX"setsid";

$SIG{CHLD} = 'IGNORE';
my $pid = fork();
exit(0) if ($pid > 0);
(setsid() != -1) || die"Can't start a new session: $!";
open (STDIN, '/dev/null') or die ("Cannot read /dev/null: $!\
");
my $logout ="logger -t test";
open (STDOUT,"|$logout")
      or die ("Cannot pipe stdout to $logout: $!\
");
open (STDERR,"|$logout")
      or die ("Cannot pipe stderr to $logout: $!\
");
my $cmd ="tail -f";
exec($cmd);
exit(1);

我用cron运行它，最后得到：

1
2
3
4
root     18616 18615  0 11:40 ?        00:00:00 [test.pl] <defunct>
root     18617     1  0 11:40 ?        00:00:00 tail -f
root     18618 18617  0 11:40 ?        00:00:00 logger -t test
root     18619 18617  0 11:40 ?        00:00:00 logger -t test

据我所知，它是记录器不喜欢的管道，如果我将STDOUT和STDERR发送到/ dev / null，则不会出现此问题。

我做错什么了吗？或者这是不可能的吗？ (CentOS 5.8)

谢谢，

leonstr

是造成它的管道。在" Programming Perl"中：

(在fork上)：

If a forked child inherits system file descriptors like STDIN and STDOUT that are
connected to a remote pipe or socket, you may have to reopen these in the child
to /dev/null. That’s because even when the parent process exits, the child will live
on with its copies of those filehandles.

相关讨论