perl / embperl -- IPC::Open3

Question

我有一个2种格式的示例程序perl & embperl

perl版本作为CGI工作，但embperl版本不起作用。

如有任何解决方案的建议或建议，将不胜感激。

操作系统: Linux版本2.6.35.6-48.fc14.i686.PAE (.)(gcc版4.5.1 20100924 (红帽4.5.1-4) (GCC) ) #1 SMP星期五2010年10月22日15:27:53

注意:我最初把这个问题发到perlmonks [x]和embperl邮件列表[x]上，但没有得到解决方案。

perl工作脚本

#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;

print "Content-type: text/plain\n\n";

my $cmd = 'ls';

my $pid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd);
close(HIS_IN);  # give end of file to kid, or feed him
my @outlines = <HIS_OUT>;              # read till EOF
my @errlines = <HIS_ERR>;              # XXX: block potential if massive
print "STDOUT: ", @outlines, "\n";
print "STDERR: ", @errlines, "\n";

waitpid( $pid, 0 );
my $child_exit_status = $? >> 8;

print "child_exit_status: $child_exit_status\n";

embperl非工作脚本

[-
  use warnings;
  use strict;
  use IPC::Open3;

  my $cmd = 'ls';

  my $pid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd);

  close(HIS_IN);  # give end of file to kid, or feed him

  my @outlines = <HIS_OUT>;              # read till EOF
  my @errlines = <HIS_ERR>;              # XXX: block potential if massive
  print OUT "STDOUT: ", @outlines, "\n";
  print OUT "STDERR: ", @errlines, "\n";

  waitpid( $pid, 0 );
  my $child_exit_status = $? >> 8;

  print OUT "child_exit_status: $child_exit_status\n";
-]

这里是我收到的输出

STDERR: ls: write error: Bad file descriptor

child_exit_status: 2

Answer 1

open3重定向与STDOUT相关的文件描述符，但不包括fd 1 (您的exec将考虑STDOUT的程序)。但这不是1。它甚至没有与它相关的文件描述符！我认为这是open3中的一个bug。我认为你可以通过以下方式来解决这个问题：

local *STDOUT;
open(STDOUT, '>&=', 1) or die $!;
...open3...

Answer 2

非常感谢池格米！

下面是工作的embperl代码。STDIN也有类似的问题。我还不知道解决这个问题的办法，但我认为这是相似的。

[-
  use warnings;
  use strict;
  use IPC::Open3;
  use POSIX;

  $http_headers_out{'Content-Type'} = "text/plain";

  my $cmd = 'ls';

  open(my $fh, '>', '/dev/null') or die $!; 

  dup2(fileno($fh), 1) or die $! if fileno($fh) != 1;

  local *STDOUT;
  open(STDOUT, '>&=', 1) or die $!;

  my $pid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd);

  close(HIS_IN);  # give end of file to kid, or feed him

  my @outlines = <HIS_OUT>;              # read till EOF
  my @errlines = <HIS_ERR>;              # XXX: block potential if massive
  print OUT "STDOUT: ", @outlines, "\n";
  print OUT "STDERR: ", @errlines, "\n";

  waitpid( $pid, 0 );
  my $child_exit_status = $? >> 8;

  print OUT "child_exit_status: $child_exit_status\n";
-]