[xen-tools-discuss] Re: [xen-shell] [PATCH] fix open command for xm list

[Ward Vandewege]

Looks like this list strips pure text attachments. Tsk tsk, bad list.

Here's the patch, inline.

Thanks,
Ward.

--- bin/xen-shell	2009-05-10 20:56:25.000000000 -0400
+++ /usr/bin/xen-shell	2009-05-10 23:03:42.000000000 -0400
@@ -1310,10 +1310,10 @@
     my ($name) = (@_);
 
     my $running = 0;
-    my @cmd = ( 'sudo', 'xm', 'list', $name, '|' );
+    my @cmd = ( 'sudo', 'xm', 'list', $name );
 
     # Lovely taint.. making this nice and hard for us.
-    my $pid = open( CMD, @cmd );
+    my $pid = open( CMD, '-|', @cmd );
     if ( defined($pid) )
     {
         while (<CMD>)
@@ -2190,9 +2190,9 @@
         print "Guest : Running\n";
 
         my $seconds = "";
-        my @cmd = ( 'sudo', 'xm', 'list', '--long', $ACTIVE, '|' );
+        my @cmd = ( 'sudo', 'xm', 'list', '--long', $ACTIVE );
 
-        open( RUNNING, @cmd );
+        open( RUNNING, '-|', @cmd );
         foreach my $line (<RUNNING>)
         {
             if ( $line =~ /\(up_time[ \t]*([0-9]+)/ )

On Sun, May 10, 2009 at 11:09:14PM -0400, Ward Vandewege wrote:
> Hi all,
> It seems the open commands used in isRunning and do_status don't work as
> expected on recent versions of perl. This was observed on 
> 
>   This is perl, v5.8.7 built for x86_64-linux-gnu-thread-multi
> 
> as well as
> 
>   This is perl, v5.8.8 built for x86_64-linux-gnu-thread-multi
> 
> on Ubuntu Dapper and Hardy, respectively.
> 
> Specifically, the problem appears to be with the pipe passed as the last
> argument in the @cmd variable.
> 
> Perl doesn't seem to like that pipe there ('Bad command or file name' error),
> which results in the 'status' command always returning 'Shutdown', regardless
> of the real status of the guest.
> 
> The perlfunction man page on the 'open' command suggests
> 
>   For three or more arguments if MODE is '|-', the filename is interpreted as
>   a command to which output is to be piped, and if MODE is '-|', the filename
>   is interpreted as a command which pipes output to us. 
> 
> which works when used in the arguments to the open call but not when simply
> added to the front of @cmd (tainting?). The attached patch implements the fix
> to make the status command work.
> 
> Thanks,
> Ward.
> 
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> 

Ward Vandewege.

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