[libvirt] [PATCH] [RESEND] qemu: record timestamp in qemu domain log

[Osier Yang]

于 2010年11月16日 21:17, Daniel P. Berrange 写道:
> On Tue, Nov 16, 2010 at 04:11:40PM +0800, Osier Yang wrote:
>> Currently only support domain start and shutdown, for domain start,
>> record timestamp before the qemu command line, and for domain shutdown,
>> just say it's shutting down with timestamp.
>>
>> * src/qemu/qemu_driver.c
>> ---
>>   src/qemu/qemu_driver.c |   47 +++++++++++++++++++++++++++++++++++++++++++++--
>>   1 files changed, 45 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>> index fd61864..423befb 100644
>> --- a/src/qemu/qemu_driver.c
>> +++ b/src/qemu/qemu_driver.c
>> @@ -3877,6 +3877,7 @@ static int qemudStartVMDaemon(virConnectPtr conn,
>>       char ebuf[1024];
>>       char *pidfile = NULL;
>>       int logfile = -1;
>> +    char *timestamp;
>>       qemuDomainObjPrivatePtr priv = vm->privateData;
>>
>>       struct qemudHookData hookData;
>> @@ -4084,7 +4085,17 @@ static int qemudStartVMDaemon(virConnectPtr conn,
>>               goto cleanup;
>>       }
>>
>> +    if ((timestamp = virTimestamp()) == NULL) {
>> +        virReportOOMError();
>> +        goto cleanup;
>> +    } else if (safewrite(logfile, timestamp, strlen(timestamp))<  0) {
>> +        VIR_WARN("Unable to write timestamp to logfile: %s",
>> +                 virStrerror(errno, ebuf, sizeof ebuf));
>> +        VIR_FREE(timestamp);
>> +    }
>
> Surely we want the VIR_FREE(timestamp) outside the 'else if'. This
> code is only freeing the memory upon write failure.

In 'if'branch, "timestamp" here returned by "virTimestamp" is
NULL, no need to free it.

And if it really needs to be freed, it should be freed
in "virTimestamp",  "virTimestamp" invokes "virAsprintf"
there, but "virAsprintf" guarantees *strp is NULL upon
failure. Isn't it? just recall you reminded me before.. :-)

>
>>   static void qemudShutdownVMDaemon(struct qemud_driver *driver,
>>                                     virDomainObjPtr vm,
>>                                     int migrated) {
>> @@ -4243,10 +4253,44 @@ static void qemudShutdownVMDaemon(struct qemud_driver *driver,
>>       virErrorPtr orig_err;
>>       virDomainDefPtr def;
>>       int i;
>> +    int logfile = -1;
>> +    char *timestamp;
>> +    char ebuf[1024];
>>
>>       VIR_DEBUG("Shutting down VM '%s' pid=%d migrated=%d",
>>                 vm->def->name, vm->pid, migrated);
>>
>> +    if ((logfile = qemudLogFD(driver, vm->def->name))<  0) {
>> +        /* To not break the normal domain shutdown process, skip the
>> +         * timestamp log writing if failed on opening log file. */
>> +        VIR_WARN("Unable to open logfile: %s",
>> +                  virStrerror(errno, ebuf, sizeof ebuf));
>> +    } else {
>> +        if ((timestamp = virTimestamp()) == NULL) {
>> +            virReportOOMError();
>> +        } else {
>> +            char *shutdownMsg;
>> +
>> +            if ((virAsprintf(&shutdownMsg, "%s: shutting down\n",
>> +                             timestamp))<  0) {
>> +                virReportOOMError();
>> +            } else {
>> +                if (safewrite(logfile, shutdownMsg, strlen(shutdownMsg))<  0) {
>> +                    VIR_WARN("Unable to write shutdownMsg to logfile: %s",
>> +                              virStrerror(errno, ebuf, sizeof ebuf));
>> +                }
>> +
>> +                VIR_FREE(shutdownMsg);
>> +            }
>
> This could easily avoid needing to alloc the shutdownMsg, eg
>
> #define POSTFIX ": shutting down\n"
>

yeah, it's much better.

>   if (safewrite(logfile, timestamp, strlen(timestamp))<  0 ||
>       safewrite(logfile, POSTFIX, strlen(POSTFIX))<  0)
>      ...
>
>
> It might be nice to include a ': starting up\n' postfix in the startup
> timestamp message too
>

yep, agree, will update. thanks.

> Regards,
> Daniel