[Libvirt-cim] [PATCH] Redirect stdout & stderr when run as out-of-process provider

[Chip Vincent]

On 09/22/2011 03:05 PM, Eduardo Lima (Etrunko) wrote:
> On 09/20/2011 07:33 PM, Chip Vincent wrote:
>> # HG changeset patch
>> # User Chip Vincent<cvincent at us.ibm.com>
>> # Date 1316557881 14400
>> # Node ID 4d95f2e9f2d8eac1565307def96bd158f5dcf160
>> # Parent  db809376d763493849c2a19f587969eaec619b75
>> Redirect stdout&  stderr when run as out-of-process provider
>>
>> When a provider is loaded in-process by Pegasus, messages sent to
>> stdout and stderr are suppressed. However, when loaded out-of-process,
>> those same messages appear on the console. This happens excessively when
>> libvirt-cim LXC_ and XEN_ classes are enumerated and libvirt sends
>> "libvir: error : no connection driver available for..." messages to stderr.
>> In development, this can sometimes prevent console usage. Until a fix is
>> made to Pegasus, we'll suppress console output during provider initialization
>> when run in out-of-process mode.
>>
>> Signed-off-by: Chip Vincent<cvincent at us.ibm.com>
>>
>> diff --git a/libxkutil/misc_util.c b/libxkutil/misc_util.c
>> --- a/libxkutil/misc_util.c
>> +++ b/libxkutil/misc_util.c
>> @@ -29,6 +29,7 @@
>>   #include<stdarg.h>
>>   #include<unistd.h>
>>   #include<pthread.h>
>> +#include<errno.h>
>
> Why are you including errno.h? Is it because of freopen(), stdout and
> stderr? I guess you should be including stdio.h if that is the case.

Without including anything new, I got a compilation error. I don't 
recall the details, but a quick google of the error pointed to errno.h. 
However, everything I search now points to stdio.h. I'll fix.

>
> Best regards, Etrunko.
>
>>   #include<libvirt/libvirt.h>
>>   #include<libvirt/virterror.h>
>>
>> @@ -540,6 +541,17 @@
>>   {
>>           int ret = 0;
>>
>> +        /* The tog-pegasus out-of-process provider feature does not
>> +        * redirect stdout and stderr, so it's done here to prevent
>> +        * any messages from taking over the console. One example is
>> +        * verbose connection failures sent to stdout by libvirt. */
>> +        if (strstr(program_invocation_short_name, "cimprovagt") != NULL) {
>> +                CU_DEBUG("Redirecting stdout and stderr");
>> +
>> +                stdout = freopen("/dev/null", "a", stdout);
>> +                stderr = freopen("/dev/null", "a", stderr);
>> +        }
>> +
>>           /* double-check lock pattern used for performance reasons */
>>           if (libvirt_initialized == 0) {
>>                   pthread_mutex_lock(&libvirt_mutex);
>>
>> _______________________________________________
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>> Libvirt-cim at redhat.com
>> https://www.redhat.com/mailman/listinfo/libvirt-cim
>
>

-- 
Chip Vincent
Open Virtualization
IBM Linux Technology Center
cvincent at linux.vnet.ibm.com