arch/sim: Handle Darwin clock IDs in clock_gettime()

arch/sim/src/Makefile

@@ -103,6 +103,10 @@ ifeq ($(CONFIG_WINDOWS_NATIVE),y)
   VPATH += :sim/win
 else
   VPATH += :sim/posix
+ifeq ($(CONFIG_HOST_MACOS),y)
+  CSRCS += sim/macos/sim_clock_gettime.c
+  REQUIREDOBJS += sim/macos/sim_clock_gettime$(OBJEXT)
+endif
 endif
 DEPPATH = $(patsubst %,--dep-path %,$(subst :, ,$(VPATH)))
 

arch/sim/src/sim/CMakeLists.txt

@@ -150,6 +150,13 @@ list(
   sim_hosttime.c
   sim_hostuart.c)
 
+if(CONFIG_HOST_MACOS)
+  # Provide a sim/macOS specific override of clock_gettime() that translates
+  # Darwin clock IDs to NuttX's CLOCK_MONOTONIC.  Keep all macOS specific logic
+  # in arch/sim/ instead of polluting sched/clock/clock_gettime.c.
+  list(APPEND SRCS macos/sim_clock_gettime.c)
+endif()
+
 if(CONFIG_HOST_MACOS AND CONFIG_HAVE_CXXINITIALIZE)
   # Keep classic __mod_init_func format so post-link lief patching works
   target_link_options(nuttx PRIVATE -Wl,-ld_classic,-no_fixup_chains)

arch/sim/src/sim/macos/sim_clock_gettime.c

@@ -0,0 +1,97 @@
+/****************************************************************************
+ * arch/sim/src/sim/macos/sim_clock_gettime.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <time.h>
+#include <errno.h>
+
+#include <nuttx/clock.h>
+#include <nuttx/compiler.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Code built for the macOS host uses Darwin's libc clock IDs.  When such
+ * code is linked into the NuttX simulator, those Darwin-specific values
+ * reach NuttX's clock_gettime() instead of Darwin's one.  Translate
+ * the Darwin monotonic clock IDs here so that the common sched/clock
+ * implementation does not need to know about them.
+ */
+
+#define DARWIN_CLOCK_MONOTONIC_RAW        4
+#define DARWIN_CLOCK_MONOTONIC_RAW_APPROX 5
+#define DARWIN_CLOCK_MONOTONIC            6
+#define DARWIN_CLOCK_UPTIME_RAW           8
+#define DARWIN_CLOCK_UPTIME_RAW_APPROX    9
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: clock_gettime
+ *
+ * Description:
+ *   sim/macOS specific override of clock_gettime() that translates Darwin
+ *   monotonic clock IDs into NuttX's CLOCK_MONOTONIC before delegating
+ *   to nxclock_gettime().
+ *
+ *   The common POSIX clock_gettime() in sched/clock/clock_gettime.c is
+ *   declared as a weak symbol, so this strong definition takes precedence
+ *   when CONFIG_HOST_MACOS is enabled.
+ *
+ ****************************************************************************/
+
+visibility_hidden
+int clock_gettime(clockid_t clock_id, FAR struct timespec *tp)
+{
+  int ret;
+
+  switch (clock_id)
+    {
+    case DARWIN_CLOCK_MONOTONIC_RAW:
+    case DARWIN_CLOCK_MONOTONIC_RAW_APPROX:
+    case DARWIN_CLOCK_MONOTONIC:
+    case DARWIN_CLOCK_UPTIME_RAW:
+    case DARWIN_CLOCK_UPTIME_RAW_APPROX:
+      clock_id = CLOCK_MONOTONIC;
+      break;
+
+    default:
+      break;
+    }
+
+  ret = nxclock_gettime(clock_id, tp);
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      return ERROR;
+    }
+
+  return OK;
+}

sched/clock/clock_gettime.c

@@ -215,7 +215,7 @@ int nxclock_gettime(clockid_t clock_id, FAR struct timespec *tp)
  *
  ****************************************************************************/
 
-int clock_gettime(clockid_t clock_id, FAR struct timespec *tp)
+int weak_function clock_gettime(clockid_t clock_id, FAR struct timespec *tp)
 {
   int ret;