mach: Use the host_get_time64 to replace the deprecated host_get_time for CLOCK_REALTIME when it's available

Check the availability of host_get_time64 and use it to replace
host_get_time for CLOCK_REALTIME when it's available. Fall back to
host_get_time if gnumach does not support host_get_time64 but the
gnumach headers do.

host_get_time is deprecated
See https://git.savannah.gnu.org/cgit/hurd/gnumach.git/commit/?id=569df850cd7badd1e36132ad3b44aa76a4d27c25
However, it's kept for backward compactbility.

* config.h.in: Add HAVE_HOST_GET_TIME64 config entry.
* sysdeps/mach/clock_gettime.c: Use host_get_time64 for CLOCK_REALTIME
  when it's possible, fall to host_get_time otherwise.
* sysdeps/mach/configure: Check the existence of host_get_time64 RPC.
* sysdeps/mach/configure.ac: Check the existence of host_get_time64 RPC.
Message-ID: <20250324052042.19803-1-zhmingluo@163.com>

config.h.in

@@ -166,6 +166,9 @@
 /* Mach specific: define if the `host_get_uptime64' RPC is available.  */
 #undef	HAVE_HOST_GET_UPTIME64
 
+/* Mach specific: define if the `host_get_time64' RPC is available.  */
+#undef	HAVE_HOST_GET_TIME64
+
 /* Mach specific: define if the `thread_set_name' RPC is available.  */
 #undef  HAVE_MACH_THREAD_SET_NAME
 

sysdeps/mach/clock_gettime.c

@@ -57,6 +57,26 @@ __clock_gettime (clockid_t clock_id, struct timespec *ts)
 
     case CLOCK_REALTIME:
       {
+#ifdef HAVE_HOST_GET_TIME64
+	time_value64_t tv_64;
+	err = __host_get_time64 (__mach_host_self (), &tv_64);
+
+	/* If err is MIG_BAD_ID, it means an old gnumach which does not
+	   support __host_get_time64 is running against the new gnumach
+	   headers which has the signature of __host_get_time64. In that
+	   case, we fall back to __host_get_time.  */
+	if (err != MIG_BAD_ID)
+	  {
+	    if (err)
+	      {
+		__set_errno (err);
+		return -1;
+	      }
+
+	    TIME_VALUE64_TO_TIMESPEC (&tv_64, ts);
+	    return 0;
+	  }
+#endif
 	/* __host_get_time can only fail if passed an invalid host_t.
 	   __mach_host_self could theoretically fail (producing an
 	   invalid host_t) due to resource exhaustion, but we assume

sysdeps/mach/configure

@@ -491,6 +491,36 @@ if test $libc_cv_mach_rpc_host_get_uptime64 = yes; then
 
 fi
 
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for host_get_time64 in mach_host.defs" >&5
+printf %s "checking for host_get_time64 in mach_host.defs... " >&6; }
+if test ${libc_cv_mach_rpc_host_get_time64+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <mach/mach_host.defs>
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP_TRADITIONAL "host_get_time64" >/dev/null 2>&1
+then :
+  libc_cv_mach_rpc_host_get_time64=yes
+else case e in #(
+  e) libc_cv_mach_rpc_host_get_time64=no ;;
+esac
+fi
+rm -rf conftest*
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_mach_rpc_host_get_time64" >&5
+printf "%s\n" "$libc_cv_mach_rpc_host_get_time64" >&6; }
+if test $libc_cv_mach_rpc_host_get_time64 = yes; then
+  printf "%s\n" "#define HAVE_HOST_GET_TIME64 1" >>confdefs.h
+
+fi
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for thread_set_name in gnumach.defs" >&5
 printf %s "checking for thread_set_name in gnumach.defs... " >&6; }
 if test ${libc_cv_mach_rpc_thread_set_name+y}

sysdeps/mach/configure.ac

@@ -94,6 +94,8 @@ mach_RPC_CHECK(mach_host.defs, host_page_size,
 	       HAVE_HOST_PAGE_SIZE)
 mach_RPC_CHECK(mach_host.defs, host_get_uptime64,
 	       HAVE_HOST_GET_UPTIME64)
+mach_RPC_CHECK(mach_host.defs, host_get_time64,
+	       HAVE_HOST_GET_TIME64)
 mach_RPC_CHECK(gnumach.defs, thread_set_name,
 	       HAVE_MACH_THREAD_SET_NAME)
 mach_RPC_CHECK(gnumach.defs, thread_get_name,