sched/semaphore: Move cancel point and errno handling to libc / user-…

…space

This moves all the public POSIX semaphore functions into libc and with
this most of the user-space logic is also moved; namely cancel point and
errno handling.

This also removes the need for the _SEM_XX macros used to differentiate
which API is used per user-/kernel mode. Such macros are henceforth
unnecessary.

arch/arm/src/stm32h7/stm32_ltdc.c

@@ -1610,7 +1610,7 @@ static void stm32_ltdc_irqconfig(void)
    */
 
   nxsem_init(g_interrupt.sem, 0, 0);
-  nxsem_set_protocol(g_interrupt.sem, SEM_PRIO_NONE);
+  nxsem_setprotocol(g_interrupt.sem, SEM_PRIO_NONE);
 
   /* Attach LTDC interrupt vector */
 

include/nuttx/semaphore.h

@@ -57,51 +57,6 @@
      {(c), (f), SEM_WAITLIST_INITIALIZER}
 #endif /* CONFIG_PRIORITY_INHERITANCE */
 
-/* Most internal nxsem_* interfaces are not available in the user space in
- * PROTECTED and KERNEL builds.  In that context, the application semaphore
- * interfaces must be used.  The differences between the two sets of
- * interfaces are:  (1) the nxsem_* interfaces do not cause cancellation
- * points and (2) they do not modify the errno variable.
- *
- * This is only important when compiling libraries (libc or libnx) that are
- * used both by the OS (libkc.a and libknx.a) or by the applications
- * (libc.a and libnx.a).  In that case, the correct interface must be
- * used for the build context.
- *
- * REVISIT:  In the flat build, the same functions must be used both by
- * the OS and by applications.  We have to use the normal user functions
- * in this case or we will fail to set the errno or fail to create the
- * cancellation point.
- */
-
-#if !defined(CONFIG_BUILD_FLAT) && defined(__KERNEL__)
-#  define _SEM_INIT(s,p,c)      nxsem_init(s,p,c)
-#  define _SEM_DESTROY(s)       nxsem_destroy(s)
-#  define _SEM_WAIT(s)          nxsem_wait(s)
-#  define _SEM_TRYWAIT(s)       nxsem_trywait(s)
-#  define _SEM_TIMEDWAIT(s,t)   nxsem_timedwait(s,t)
-#  define _SEM_CLOCKWAIT(s,c,t) nxsem_clockwait(s,c,t)
-#  define _SEM_POST(s)          nxsem_post(s)
-#  define _SEM_GETVALUE(s,v)    nxsem_get_value(s,v)
-#  define _SEM_GETPROTOCOL(s,p) nxsem_get_protocol(s,p)
-#  define _SEM_SETPROTOCOL(s,p) nxsem_set_protocol(s,p)
-#  define _SEM_ERRNO(r)         (-(r))
-#  define _SEM_ERRVAL(r)        (r)
-#else
-#  define _SEM_INIT(s,p,c)      sem_init(s,p,c)
-#  define _SEM_DESTROY(s)       sem_destroy(s)
-#  define _SEM_WAIT(s)          sem_wait(s)
-#  define _SEM_TRYWAIT(s)       sem_trywait(s)
-#  define _SEM_TIMEDWAIT(s,t)   sem_timedwait(s,t)
-#  define _SEM_CLOCKWAIT(s,c,t) sem_clockwait(s,c,t)
-#  define _SEM_GETVALUE(s,v)    sem_getvalue(s,v)
-#  define _SEM_POST(s)          sem_post(s)
-#  define _SEM_GETPROTOCOL(s,p) sem_getprotocol(s,p)
-#  define _SEM_SETPROTOCOL(s,p) sem_setprotocol(s,p)
-#  define _SEM_ERRNO(r)         errno
-#  define _SEM_ERRVAL(r)        (-errno)
-#endif
-
 /****************************************************************************
  * Public Type Definitions
  ****************************************************************************/
@@ -473,7 +428,7 @@ int nxsem_reset(FAR sem_t *sem, int16_t count);
 #define nxsem_get_protocol(s,p) sem_getprotocol(s,p)
 
 /****************************************************************************
- * Name: nxsem_set_protocol
+ * Name: nxsem_setprotocol
  *
  * Description:
  *    Set semaphore protocol attribute.
@@ -493,7 +448,7 @@ int nxsem_reset(FAR sem_t *sem, int16_t count);
  *    becomes *permanently* a holder of the semaphore and may have its
  *    priority boosted when any other task tries to acquire the semaphore.
  *
- *    The fix is to call nxsem_set_protocol(SEM_PRIO_NONE) immediately after
+ *    The fix is to call nxsem_setprotocol(SEM_PRIO_NONE) immediately after
  *    the sem_init() call so that there will be no priority inheritance
  *    operations on this semaphore.
  *
@@ -509,7 +464,7 @@ int nxsem_reset(FAR sem_t *sem, int16_t count);
  *
  ****************************************************************************/
 
-int nxsem_set_protocol(FAR sem_t *sem, int protocol);
+int nxsem_setprotocol(FAR sem_t *sem, int protocol);
 
 /****************************************************************************
  * Name: nxsem_wait_uninterruptible

include/sys/syscall_lookup.h

@@ -75,17 +75,15 @@ SYSCALL_LOOKUP(sethostname,                2)
 
 /* Semaphores */
 
+SYSCALL_LOOKUP(nxsem_destroy,              1)
+SYSCALL_LOOKUP(nxsem_post,                 1)
+SYSCALL_LOOKUP(nxsem_clockwait,            3)
+SYSCALL_LOOKUP(nxsem_timedwait,            2)
+SYSCALL_LOOKUP(nxsem_trywait,              1)
 SYSCALL_LOOKUP(nxsem_wait,                 1)
 
-SYSCALL_LOOKUP(sem_destroy,                1)
-SYSCALL_LOOKUP(sem_post,                   1)
-SYSCALL_LOOKUP(sem_clockwait,              3)
-SYSCALL_LOOKUP(sem_timedwait,              2)
-SYSCALL_LOOKUP(sem_trywait,                1)
-SYSCALL_LOOKUP(sem_wait,                   1)
-
 #ifdef CONFIG_PRIORITY_INHERITANCE
-  SYSCALL_LOOKUP(sem_setprotocol,          2)
+  SYSCALL_LOOKUP(nxsem_setprotocol,        2)
 #endif
 
 /* Named semaphores */

libs/libc/misc/lib_mutex.c

@@ -82,18 +82,18 @@ static bool nxmutex_is_reset(FAR mutex_t *mutex)
 
 int nxmutex_init(FAR mutex_t *mutex)
 {
-  int ret = _SEM_INIT(&mutex->sem, 0, 1);
+  int ret = nxsem_init(&mutex->sem, 0, 1);
 
   if (ret < 0)
     {
-      return _SEM_ERRVAL(ret);
+      return ret;
     }
 
   mutex->holder = NXMUTEX_NO_HOLDER;
 #ifdef CONFIG_PRIORITY_INHERITANCE
-  _SEM_SETPROTOCOL(&mutex->sem, SEM_TYPE_MUTEX | SEM_PRIO_INHERIT);
+  nxsem_setprotocol(&mutex->sem, SEM_TYPE_MUTEX | SEM_PRIO_INHERIT);
 #else
-  _SEM_SETPROTOCOL(&mutex->sem, SEM_TYPE_MUTEX);
+  nxsem_setprotocol(&mutex->sem, SEM_TYPE_MUTEX);
 #endif
   return ret;
 }
@@ -119,11 +119,11 @@ int nxmutex_init(FAR mutex_t *mutex)
 
 int nxmutex_destroy(FAR mutex_t *mutex)
 {
-  int ret = _SEM_DESTROY(&mutex->sem);
+  int ret = nxsem_destroy(&mutex->sem);
 
   if (ret < 0)
     {
-      return _SEM_ERRVAL(ret);
+      return ret;
     }
 
   mutex->holder = NXMUTEX_NO_HOLDER;
@@ -167,7 +167,7 @@ bool nxmutex_is_locked(FAR mutex_t *mutex)
   int cnt;
   int ret;
 
-  ret = _SEM_GETVALUE(&mutex->sem, &cnt);
+  ret = nxsem_get_value(&mutex->sem, &cnt);
 
   return ret >= 0 && cnt < 1;
 }
@@ -242,10 +242,10 @@ int nxmutex_trylock(FAR mutex_t *mutex)
   int ret;
 
   DEBUGASSERT(!nxmutex_is_hold(mutex));
-  ret = _SEM_TRYWAIT(&mutex->sem);
+  ret = nxsem_trywait(&mutex->sem);
   if (ret < 0)
     {
-      return _SEM_ERRVAL(ret);
+      return ret;
     }
 
   mutex->holder = _SCHED_GETTID();
@@ -291,11 +291,7 @@ int nxmutex_timedlock(FAR mutex_t *mutex, unsigned int timeout)
 
   do
     {
-      ret = _SEM_CLOCKWAIT(&mutex->sem, CLOCK_MONOTONIC, &rqtp);
-      if (ret < 0)
-        {
-          ret = _SEM_ERRVAL(ret);
-        }
+      ret = nxsem_clockwait(&mutex->sem, CLOCK_MONOTONIC, &rqtp);
     }
   while (ret == -EINTR || ret == -ECANCELED);
 
@@ -340,11 +336,10 @@ int nxmutex_unlock(FAR mutex_t *mutex)
 
   mutex->holder = NXMUTEX_NO_HOLDER;
 
-  ret = _SEM_POST(&mutex->sem);
+  ret = nxsem_post(&mutex->sem);
   if (ret < 0)
     {
       mutex->holder = _SCHED_GETTID();
-      ret = _SEM_ERRVAL(ret);
     }
 
   return ret;

libs/libc/semaphore/CMakeLists.txt

@@ -18,10 +18,16 @@
 #
 # ##############################################################################
 
-set(SRCS sem_init.c sem_getprotocol.c sem_getvalue.c)
-
-if(NOT CONFIG_PRIORITY_INHERITANCE)
-  list(APPEND SRCS sem_setprotocol.c)
-endif()
+set(SRCS
+    sem_init.c
+    sem_setprotocol.c
+    sem_getprotocol.c
+    sem_getvalue.c
+    sem_destroy.c
+    sem_wait.c
+    sem_trywait.c
+    sem_timedwait.c
+    sem_clockwait.c
+    sem_post.c)
 
 target_sources(c PRIVATE ${SRCS})

libs/libc/semaphore/Make.defs

@@ -20,11 +20,9 @@
 
 # Add the semaphore C files to the build
 
-CSRCS += sem_init.c sem_getprotocol.c sem_getvalue.c
-
-ifneq ($(CONFIG_PRIORITY_INHERITANCE),y)
-CSRCS += sem_setprotocol.c
-endif
+CSRCS += sem_init.c sem_setprotocol.c sem_getprotocol.c sem_getvalue.c
+CSRCS += sem_destroy.c sem_wait.c sem_trywait.c sem_timedwait.c
+CSRCS += sem_clockwait.c sem_post.c
 
 # Add the semaphore directory to the build
 

libs/libc/semaphore/sem_clockwait.c

@@ -0,0 +1,104 @@
+/****************************************************************************
+ * libs/libc/semaphore/sem_clockwait.c
+ *
+ * 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/cancelpt.h>
+#include <nuttx/semaphore.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sem_clockwait
+ *
+ * Description:
+ *   This function will lock the semaphore referenced by sem as in the
+ *   sem_wait() function. However, if the semaphore cannot be locked without
+ *   waiting for another process or thread to unlock the semaphore by
+ *   performing a sem_post() function, this wait will be terminated when the
+ *   specified timeout expires.
+ *
+ *   The timeout will expire when the absolute time specified by abstime
+ *   passes, as measured by the clock on which timeouts are based (that is,
+ *   when the value of that clock equals or exceeds abstime), or if the
+ *   absolute time specified by abstime has already been passed at the
+ *   time of the call.
+ *
+ * Input Parameters:
+ *   sem     - Semaphore object
+ *   clockid - The timing source to use in the conversion
+ *   abstime - The absolute time to wait until a timeout is declared.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success.  On failure, -1 (ERROR) is returned
+ *   and the errno is set appropriately:
+ *
+ *   EINVAL    The sem argument does not refer to a valid semaphore.  Or the
+ *             thread would have blocked, and the abstime parameter specified
+ *             a nanoseconds field value less than zero or greater than or
+ *             equal to 1000 million.
+ *   ETIMEDOUT The semaphore could not be locked before the specified timeout
+ *             expired.
+ *   EDEADLK   A deadlock condition was detected.
+ *   EINTR     A signal interrupted this function.
+ *   ECANCELED May be returned if the thread is canceled while waiting.
+ *
+ ****************************************************************************/
+
+int sem_clockwait(FAR sem_t *sem, clockid_t clockid,
+                  FAR const struct timespec *abstime)
+{
+  int ret;
+
+  /* Verify the input parameters and, in case of an error, set
+   * errno appropriately.
+   */
+
+  if (sem == NULL || abstime == NULL)
+    {
+      set_errno(EINVAL);
+      return ERROR;
+    }
+
+  /* sem_timedwait() is a cancellation point */
+
+  enter_cancellation_point();
+
+  /* Let nxsem_timedout() do the work */
+
+  ret = nxsem_clockwait(sem, clockid, abstime);
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      ret = ERROR;
+    }
+
+  leave_cancellation_point();
+  return ret;
+}