Re: [Qemu-devel] [PATCH v2 REPOST] oslib-win32: only provide localtime_r/gmtime_r if missing

["Denis V. Lunev" <den@openvz.org>]

On 09/22/2015 05:13 PM, Daniel P. Berrange wrote:
> The oslib-win32 file currently provides a localtime_r and
> gmtime_r replacement unconditionally. Some versions of
> Mingw64 would provide crude macros for localtime_r/gmtime_r
> which QEMU takes care to disable. Latest versions of Mingw64
> now provide actual functions for localtime_r/gmtime_r, but
> with a twist that you have to include unistd.h or pthread.h
> before including time.h.  By luck some files in QEMU have
> such an include order, resulting in compile errors:
>
>    CC    util/osdep.o
> In file included from include/qemu-common.h:48:0,
>                   from util/osdep.c:48:
> include/sysemu/os-win32.h:77:12: error: redundant redeclaration of 'gmtime_r' [-Werror=redundant-decls]
>   struct tm *gmtime_r(const time_t *timep, struct tm *result);
>              ^
> In file included from include/qemu-common.h:35:0,
>                   from util/osdep.c:48:
> /usr/i686-w64-mingw32/sys-root/mingw/include/time.h:272:107: note: previous definition of 'gmtime_r' was here
> In file included from include/qemu-common.h:48:0,
>                   from util/osdep.c:48:
> include/sysemu/os-win32.h:79:12: error: redundant redeclaration of 'localtime_r' [-Werror=redundant-decls]
>   struct tm *localtime_r(const time_t *timep, struct tm *result);
>              ^
> In file included from include/qemu-common.h:35:0,
>                   from util/osdep.c:48:
> /usr/i686-w64-mingw32/sys-root/mingw/include/time.h:269:107: note: previous definition of 'localtime_r' was here
>
> This change adds a configure test to see if localtime_r
> exits, and only enables the QEMU impl if missing. We also
> re-arrange qemu-common.h try attempt to guarantee that all
> source files get unistd.h before time.h and thus see the
> localtime_r/gmtime_r defs.
>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>   configure                 | 34 ++++++++++++++++++++++++++++++++++
>   include/qemu/osdep.h      |  4 +++-
>   include/sysemu/os-win32.h |  2 ++
>   util/oslib-win32.c        |  2 ++
>   4 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 52f5b79..4654be8 100755
> --- a/configure
> +++ b/configure
> @@ -1737,6 +1737,37 @@ else
>   fi
>   
>   ##########################################
> +# Mingw64 localtime_r/gmtime_r check
> +
> +if test "$mingw32" = "yes"; then
> +    # Some versions of Mingw32/64 lack localtime_r
> +    # and gmtime_r entirely
> +    #
> +    # Some versions of Mingw64 define a macro for
> +    # localtime_r/gmtime_r/etc
> +    #
> +    # Some versions of Ming64 will define functions
> +    # for localtime_r/gmtime_r, but only if you have
> +    # _POSIX_THREAD_SAFE_FUNCTIONS defined. For fun
> +    # though, unistd.h and pthread.h both define
> +    # that for you.
> +    #
> +    # So this #undef localtime_r and #include <unistd.h>
> +    # are not in fact redundant
> +cat > $TMPC << EOF
> +#include <unistd.h>
> +#include <time.h>
> +#undef localtime_r
> +int main(void) { localtime_r(NULL, NULL); return 0; }
> +EOF
> +    if compile_prog "" "" ; then
> +        localtime_r="yes"
> +    else
> +        localtime_r="no"
> +    fi
> +fi
> +
> +##########################################
>   # pkg-config probe
>   
>   if ! has "$pkg_config_exe"; then
> @@ -5050,6 +5081,9 @@ fi
>   if test "$zero_malloc" = "yes" ; then
>     echo "CONFIG_ZERO_MALLOC=y" >> $config_host_mak
>   fi
> +if test "$localtime_r" = "yes" ; then
> +  echo "CONFIG_LOCALTIME_R=y" >> $config_host_mak
> +fi
>   if test "$qom_cast_debug" = "yes" ; then
>     echo "CONFIG_QOM_CAST_DEBUG=y" >> $config_host_mak
>   fi
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index ab3c876..e490028 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -38,10 +38,12 @@
>   #include <strings.h>
>   #include <inttypes.h>
>   #include <limits.h>
> +/* Put unistd.h before time.h as that triggers localtime_r/gmtime_r
> + * function availability on recentish Mingw64 platforms */
> +#include <unistd.h>
>   #include <time.h>
>   #include <ctype.h>
>   #include <errno.h>
> -#include <unistd.h>
>   #include <fcntl.h>
>   #include <sys/stat.h>
>   #include <sys/time.h>
> diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h
> index 706d85a..13dcef6 100644
> --- a/include/sysemu/os-win32.h
> +++ b/include/sysemu/os-win32.h
> @@ -73,10 +73,12 @@
>   #define siglongjmp(env, val) longjmp(env, val)
>   
>   /* Missing POSIX functions. Don't use MinGW-w64 macros. */
> +#ifndef CONFIG_LOCALTIME_R
>   #undef gmtime_r
>   struct tm *gmtime_r(const time_t *timep, struct tm *result);
>   #undef localtime_r
>   struct tm *localtime_r(const time_t *timep, struct tm *result);
> +#endif /* CONFIG_LOCALTIME_R */
>   
>   
>   static inline void os_setup_signal_handling(void) {}
> diff --git a/util/oslib-win32.c b/util/oslib-win32.c
> index 730a670..08f5a9c 100644
> --- a/util/oslib-win32.c
> +++ b/util/oslib-win32.c
> @@ -95,6 +95,7 @@ void qemu_anon_ram_free(void *ptr, size_t size)
>       }
>   }
>   
> +#ifndef CONFIG_LOCALTIME_R
>   /* FIXME: add proper locking */
>   struct tm *gmtime_r(const time_t *timep, struct tm *result)
>   {
> @@ -118,6 +119,7 @@ struct tm *localtime_r(const time_t *timep, struct tm *result)
>       }
>       return p;
>   }
> +#endif /* CONFIG_LOCALTIME_R */
>   
>   void qemu_set_block(int fd)
>   {
Reviewed-by: Denis V. Lunev <den@openvz.org>