Re: [Qemu-devel] [PULL 14/19] log: Redirect stderr to logfile if deamonized

[Paolo Bonzini]

On 29/02/2016 11:04, Ján Tomko wrote:
> On Mon, Feb 29, 2016 at 10:07:47AM +0100, Paolo Bonzini wrote:
>>
>>
>> On 29/02/2016 09:57, Ján Tomko wrote:
>>> qemu-system-x86_64 -S -no-user-config -nodefaults -nographic -M none
>>>  -qmp unix:/var/lib/libvirt/qemu/capabilities.monitor.sock,server,nowait
>>>  -pidfile /var/lib/libvirt/qemu/capabilities.pidfile -daemonize
>>
>> Can you test this patch?
>>
>> diff --git a/util/log.c b/util/log.c
>> index 4dff00b..9402880 100644
>> --- a/util/log.c
>> +++ b/util/log.c
>> @@ -56,7 +56,8 @@ void do_qemu_set_log(int log_flags, bool use_own_buffers)
>>  #ifdef CONFIG_TRACE_LOG
>>      qemu_loglevel |= LOG_TRACE;
>>  #endif
>> -    if ((qemu_loglevel || is_daemonized()) && !qemu_logfile) {
>> +    if (!qemu_logfile &&
>> +        (qemu_loglevel || (is_daemonized() && logfilename)) {
>>          if (logfilename) {
>>              qemu_logfile = fopen(logfilename, log_append ? "a" : "w");
>>              if (!qemu_logfile) {
>>
>> Thanks,
> 
> Still hangs,
> 
> (gdb) list
> 54      {
> 55          qemu_loglevel = log_flags;
> 56      #ifdef CONFIG_TRACE_LOG
> 57          qemu_loglevel |= LOG_TRACE;
> 58      #endif
> 59          sleep(10);
> 60          if (!qemu_logfile &&
> 61              (qemu_loglevel || (is_daemonized() && logfilename))) {
> 62              if (logfilename) {
> 63                  qemu_logfile = fopen(logfilename, log_append ? "a" : "w");
> (gdb) p qemu_logfile
> $1 = (FILE *) 0x0
> (gdb) p qemu_loglevel
> $2 = 32768
> (gdb) p logfilename
> $3 = 0x0
> (gdb) call is_daemonized()
> $4 = true

Second attempt:

diff --git a/util/log.c b/util/log.c
index 4dff00b..1530a60 100644
--- a/util/log.c
+++ b/util/log.c
@@ -56,7 +56,8 @@ void do_qemu_set_log(int log_flags, bool use_own_buffers)
 #ifdef CONFIG_TRACE_LOG
     qemu_loglevel |= LOG_TRACE;
 #endif
-    if ((qemu_loglevel || is_daemonized()) && !qemu_logfile) {
+    if (!qemu_logfile &&
+        (is_daemonized() ? logfilename : qemu_loglevel)) {
         if (logfilename) {
             qemu_logfile = fopen(logfilename, log_append ? "a" : "w");
             if (!qemu_logfile) {
@@ -72,6 +73,7 @@ void do_qemu_set_log(int log_flags, bool use_own_buffers)
             }
         } else {
             /* Default to stderr if no log file specified */
+            assert(!is_daemonized());
             qemu_logfile = stderr;
         }
         /* must avoid mmap() usage of glibc by setting a buffer "by hand" */


Paolo