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Date: Wed, 09 Jan 2013 10:47:26 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 1/2] oslib-win32: add lock for gmtime_r()
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To: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Cc: stefanha@gmail.com, aliguori@us.ibm.com, qemu-devel@nongnu.org, quintela@redhat.com

Il 09/01/2013 07:18, Wenchao Xia ha scritto:
>   Also changed the caller of gmtime() to gmtime_r().

Should be a separate patch.

Also, what is the reason to add this lock?  They are already protected
by the BQL.

Paolo

> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
> ---
>  oslib-win32.c |    6 +++++-
>  vl.c          |    4 ++--
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/oslib-win32.c b/oslib-win32.c
> index e7e283e..74e0c52 100644
> --- a/oslib-win32.c
> +++ b/oslib-win32.c
> @@ -32,6 +32,8 @@
>  #include "trace.h"
>  #include "qemu/sockets.h"
>  
> +static GStaticMutex time_lock = G_STATIC_MUTEX_INIT;
> +
>  void *qemu_oom_check(void *ptr)
>  {
>      if (ptr == NULL) {
> @@ -74,15 +76,17 @@ void qemu_vfree(void *ptr)
>      VirtualFree(ptr, 0, MEM_RELEASE);
>  }
>  
> -/* FIXME: add proper locking */
> +/* FIXME: add proper locking in MinGW */
>  struct tm *gmtime_r(const time_t *timep, struct tm *result)
>  {
> +    g_static_mutex_lock(&time_lock);
>      struct tm *p = gmtime(timep);
>      memset(result, 0, sizeof(*result));
>      if (p) {
>          *result = *p;
>          p = result;
>      }
> +    g_static_mutex_unlock(&time_lock);
>      return p;
>  }
>  
> diff --git a/vl.c b/vl.c
> index 79e5122..8d7864c 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -454,12 +454,12 @@ void qemu_get_timedate(struct tm *tm, int offset)
>      ti += offset;
>      if (rtc_date_offset == -1) {
>          if (rtc_utc)
> -            ret = gmtime(&ti);
> +            ret = gmtime_r(&ti, tm);
>          else
>              ret = localtime(&ti);
>      } else {
>          ti -= rtc_date_offset;
> -        ret = gmtime(&ti);
> +        ret = gmtime_r(&ti, tm);
>      }
>  
>      memcpy(tm, ret, sizeof(struct tm));
>