问题
I have a sample program in 2 formats perl & embperl
The perl version works as a CGI but the embperl version does not work.
Any suggestions or pointers to solutions would be appreciated
OS: Linux version 2.6.35.6-48.fc14.i686.PAE (...) (gcc version 4.5.1 20100924 (Red Hat 4.5.1-4) (GCC) ) #1 SMP Fri Oct 22 15:27:53 UTC 2010
NOTE: I originally posted this question to perlmonks [x] and the embperl mailing list [x] but didn't get a solution.
perl working script
#!/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 non-working script
[-
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";
-]
Here is the output I receive
STDERR: ls: write error: Bad file descriptor
child_exit_status: 2
回答1:
open3
redirects the file descriptor associated with STDOUT, excepting it to be fd 1
(what the program you exec
will consider STDOUT). But it's not 1
. It doesn't even have a file descriptor associated with it! I consider this a bug in open3
. I think you can work around it as follows:
local *STDOUT;
open(STDOUT, '>&=', 1) or die $!;
...open3...
回答2:
Thank you sooo much to ikegami!!!!
Here is the embperl code that works. P.S. There is a similar problem with STDIN. I don't know the solution to that yet, but I think it is similar.
[-
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";
-]
来源:https://stackoverflow.com/questions/23770338/perl-embperl-ipcopen3