Squashed commit of the following:

Replace all calls to sigprocmask() in the OS proper with calls to nxsig_procmask().

    sched/signal:  Add internal OS interface nxsig_procmask().  This internal interface is equivalent to the standard sigprocmask() used by applications except that it does not modify the errno value.  Also fixes a problem in that the original sigprocmask() was not setting the errno.

binfmt/binfmt_schedunload.c

@@ -45,6 +45,7 @@
 
 #include <nuttx/irq.h>
 #include <nuttx/kmalloc.h>
+#include <nuttx/signal.h>
 #include <nuttx/binfmt/binfmt.h>
 
 #include "binfmt.h"
@@ -100,10 +101,10 @@ static void unload_list_add(pid_t pid, FAR struct binary_s *bin)
 
   bin->pid = pid;
 
-  /* Disable deliver of any signals while we muck with the list.  The graceful
+  /* Disable deliver of any signals while we muck with the list.  The
-   * way to do this would be block delivery of SIGCHLD would be with
+   * graceful way to do this would be block delivery of SIGCHLD would be
-   * sigprocmask.  Here we do it the quick'n'dirty way by just disabling
+   * with nxsig_procmask.  Here we do it the quick'n'dirty way by just
-   * interrupts.
+   * disabling interrupts.
    */
 
   flags = enter_critical_section();
@@ -277,13 +278,10 @@ int schedule_unload(pid_t pid, FAR struct binary_s *bin)
 
   (void)sigemptyset(&set);
   (void)sigaddset(&set, SIGCHLD);
-  ret = sigprocmask(SIG_UNBLOCK, &set, NULL);
+  ret = nxsig_procmask(SIG_UNBLOCK, &set, NULL);
-  if (ret != OK)
+  if (ret < 0)
     {
-      /* The errno value will get trashed by the following debug output */
+      berr("ERROR: nxsig_procmask failed: %d\n", ret);
-
-      ret = -get_errno();
-      berr("ERROR: sigprocmask failed: %d\n", ret);
       return ret;
     }
 

include/nuttx/signal.h

@@ -51,6 +51,48 @@
 
 struct timespec;  /* Forward reference */
 
+/****************************************************************************
+ * Name: nxsig_procmask
+ *
+ * Description:
+ *   This function allows the calling process to examine and/or change its
+ *   signal mask.  If the 'set' is not NULL, then it points to a set of
+ *   signals to be used to change the currently blocked set.  The value of
+ *   'how' indicates the manner in which the set is changed.
+ *
+ *   If there any pending unblocked signals after the call to
+ *   nxsig_procmask(), those signals will be delivered before
+ *    nxsig_procmask() returns.
+ *
+ *   If nxsig_procmask() fails, the signal mask of the process is not changed
+ *   by this function call.
+ *
+ *   This is an internal OS interface.  It is functionally equivalent to
+ *   sigprocmask() except that it does not modify the errno value.
+ *
+ * Parameters:
+ *   how - How the signal mast will be changed:
+ *         SIG_BLOCK   - The resulting set is the union of the current set
+ *                       and the signal set pointed to by 'set'.
+ *         SIG_UNBLOCK - The resulting set is the intersection of the current
+ *                       set and the complement of the signal set pointed to
+ *                       by 'set'.
+ *         SIG_SETMASK - The resulting set is the signal set pointed to by
+ *                       'set'.
+ *   set  - Location of the new signal mask
+ *   oset - Location to store the old signal mask
+ *
+ * Return Value:
+ *   This is an internal OS interface and should not be used by applications.
+ *   It follows the NuttX internal error return policy:  Zero (OK) is
+ *   returned on success.  A negated errno value is returned on failure.
+ *
+ *    EINVAL - The 'how' argument is invalid.
+ *
+ ****************************************************************************/
+
+int nxsig_procmask(int how, FAR const sigset_t *set, FAR sigset_t *oset);
+
 /****************************************************************************
  * Name: nxsig_queue
  *

sched/pthread/pthread_exit.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/pthread/pthread_exit.c
  *
- *   Copyright (C) 2007, 2009, 2011-2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2011-2013, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,6 +48,7 @@
 #include <debug.h>
 
 #include <nuttx/arch.h>
+#include <nuttx/signal.h>
 
 #include "sched/sched.h"
 #include "task/task.h"
@@ -90,7 +91,7 @@ void pthread_exit(FAR void *exit_value)
 #ifndef CONFIG_DISABLE_SIGNALS
   {
     sigset_t set = ALL_SIGNAL_SET;
-    (void)sigprocmask(SIG_SETMASK, &set, NULL);
+    (void)nxsig_procmask(SIG_SETMASK, &set, NULL);
   }
 #endif
 

sched/pthread/pthread_sigmask.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/pthread/pthread_sigmask.c
  *
- *   Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -52,8 +52,8 @@
  * Name: pthread_sigmask
  *
  * Description:
- *   This function is a simple wrapper around sigprocmask().
+ *   This function is a simple wrapper around nxsig_procmask().
- *   See the sigprocmask() function description for further
+ *   See the nxsig_procmask() function description for further
  *   information.
  *
  * Parameters:
@@ -70,19 +70,13 @@
  *   oset - Location to store the old signal mask
  *
  * Return Value:
- *   0 (OK) or EINVAL if how is invalid.
+ *   On success, this function will return 0 (OK).  It will return EINVAL if
- *
+ *   how is invalid.
- * Assumptions:
  *
  ****************************************************************************/
 
 int pthread_sigmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
 {
-  int ret = sigprocmask(how, set, oset);
+  int ret = nxsig_procmask(how, set, oset);
-  if (ret != OK)
+  return ret < 0 ? -ret : OK;
-    {
-      ret = EINVAL;
-    }
-
-  return ret;
 }

sched/signal/sig_mqnotempty.c

@@ -1,7 +1,8 @@
 /****************************************************************************
  * sched/signal/sig_mqnotempty.c
  *
- *   Copyright (C) 2007-2009, 2013, 2015, 2017 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2013, 2015, 2017 Gregory Nutt. All rights
+ *     reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without

sched/signal/sig_procmask.c

@@ -1,7 +1,8 @@
 /****************************************************************************
  * sched/signal/sig_procmask.c
  *
- *   Copyright (C) 2007-2009, 2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2014, 2016-2017 Gregory Nutt. All rights
+ *     reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -42,14 +43,16 @@
 #include <unistd.h>
 #include <signal.h>
 #include <time.h>
-#include <assert.h>
-#include <debug.h>
 #include <sched.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
 
 #include <nuttx/irq.h>
 #include <nuttx/arch.h>
 #include <nuttx/wdog.h>
 #include <nuttx/kmalloc.h>
+#include <nuttx/signal.h>
 
 #include "sched/sched.h"
 #include "signal/signal.h"
@@ -59,7 +62,7 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: sigprocmask
+ * Name: nxsig_procmask
  *
  * Description:
  *   This function allows the calling process to examine and/or change its
@@ -67,12 +70,16 @@
  *   signals to be used to change the currently blocked set.  The value of
  *   'how' indicates the manner in which the set is changed.
  *
- *   If there any pending unblocked signals after the call to sigprocmask(),
+ *   If there any pending unblocked signals after the call to
- *   those signals will be delivered before sigprocmask() returns.
+ *   nxsig_procmask(), those signals will be delivered before
+ *    nxsig_procmask() returns.
  *
- *   If sigprocmask() fails, the signal mask of the process is not changed
+ *   If nxsig_procmask() fails, the signal mask of the process is not changed
  *   by this function call.
  *
+ *   This is an internal OS interface.  It is functionally equivalent to
+ *   sigprocmask() except that it does not modify the errno value.
+ *
  * Parameters:
  *   how - How the signal mast will be changed:
  *         SIG_BLOCK   - The resulting set is the union of the current set
@@ -86,13 +93,15 @@
  *   oset - Location to store the old signal mask
  *
  * Return Value:
- *   0 (OK), or -1 (ERROR) if how is invalid.
+ *   This is an internal OS interface and should not be used by applications.
+ *   It follows the NuttX internal error return policy:  Zero (OK) is
+ *   returned on success.  A negated errno value is returned on failure.
  *
- * Assumptions:
+ *     EINVAL - The 'how' argument is invalid.
  *
  ****************************************************************************/
 
-int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
+int nxsig_procmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
 {
   FAR struct tcb_s *rtcb = this_task();
   sigset_t   oldsigprocmask;
@@ -111,7 +120,7 @@ int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
 
   /* Modify the current signal mask if so requested */
 
-  if (set)
+  if (set != NULL)
     {
       /* Some of these operations are non-atomic.  We need to protect
        * ourselves from attempts to process signals from interrupts
@@ -146,7 +155,7 @@ int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
             break;
 
           default:
-            ret = ERROR;
+            ret = -EINVAL;
             break;
         }
 
@@ -160,3 +169,52 @@ int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
   sched_unlock();
   return ret;
 }
+
+/****************************************************************************
+ * Name: sigprocmask
+ *
+ * Description:
+ *   This function allows the calling process to examine and/or change its
+ *   signal mask.  If the 'set' is not NULL, then it points to a set of
+ *   signals to be used to change the currently blocked set.  The value of
+ *   'how' indicates the manner in which the set is changed.
+ *
+ *   If there any pending unblocked signals after the call to sigprocmask(),
+ *   those signals will be delivered before sigprocmask() returns.
+ *
+ *   If sigprocmask() fails, the signal mask of the process is not changed
+ *   by this function call.
+ *
+ * Parameters:
+ *   how - How the signal mast will be changed:
+ *         SIG_BLOCK   - The resulting set is the union of the current set
+ *                       and the signal set pointed to by 'set'.
+ *         SIG_UNBLOCK - The resulting set is the intersection of the current
+ *                       set and the complement of the signal set pointed to
+ *                       by 'set'.
+ *         SIG_SETMASK - The resulting set is the signal set pointed to by
+ *                       'set'.
+ *   set  - Location of the new signal mask
+ *   oset - Location to store the old signal mask
+ *
+ * Return Value:
+ *   This function will return 0 (OK) on success or -1 (ERROR) if how is
+ *   invalid.  In the latter case, the errno variable will be set to EINVAL.
+ *
+ ****************************************************************************/
+
+int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
+{
+  int ret;
+
+  /* Let nxsig_procmask do all of the work */
+
+  ret = nxsig_procmask(how, set, oset);
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      ret = ERROR;
+    }
+
+  return ret;
+}

sched/task/task_setup.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/task/task_setup.c
  *
- *   Copyright (C) 2007-2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2014, 2016-2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -47,6 +47,7 @@
 #include <debug.h>
 
 #include <nuttx/arch.h>
+#include <nuttx/signal.h>
 
 #include "sched/sched.h"
 #include "pthread/pthread.h"
@@ -406,7 +407,7 @@ static int thread_schedsetup(FAR struct tcb_s *tcb, int priority,
        * inherit the signal mask of the parent thread.
        */
 
-      (void)sigprocmask(SIG_SETMASK, NULL, &tcb->sigprocmask);
+      (void)nxsig_procmask(SIG_SETMASK, NULL, &tcb->sigprocmask);
 #endif
 
       /* Initialize the task state.  It does not get a valid state

sched/task/task_spawnparms.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/task/task_spawnparms.c
  *
- *   Copyright (C) 2013, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013, 2015, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -44,6 +44,7 @@
 #include <spawn.h>
 #include <debug.h>
 
+#include <nuttx/signal.h>
 #include <nuttx/spawn.h>
 
 #include "task/spawn.h"
@@ -317,7 +318,7 @@ int spawn_proxyattrs(FAR const posix_spawnattr_t *attr,
 #ifndef CONFIG_DISABLE_SIGNALS
   if (attr && (attr->flags & POSIX_SPAWN_SETSIGMASK) != 0)
     {
-      (void)sigprocmask(SIG_SETMASK, &attr->sigmask, NULL);
+      (void)nxsig_procmask(SIG_SETMASK, &attr->sigmask, NULL);
     }
 
   /* Were we also requested to perform file actions? */