Correct errno handling

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@136 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 117 insertions, 57 deletions

diff --git a/nuttx/sched/pthread_getschedparam.c b/nuttx/sched/pthread_getschedparam.c
index 0e410ef9e..02dbd8faa 100644
--- a/nuttx/sched/pthread_getschedparam.c
+++ b/nuttx/sched/pthread_getschedparam.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * pthread_getschedparam.c
  *
  *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <sys/types.h>
 #include <pthread.h>
@@ -44,47 +44,64 @@
 #include <debug.h>
 #include "pthread_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Definitions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Type Declarations
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Variables
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Variables
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Public Functions
- ************************************************************/
+ *****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Function:  pthread_getschedparam
  *
  * Description:
- *   Obtain the thread scheduling parameters.
+ *   The pthread_getschedparam() functions will get the scheduling policy and
+ *   parameters of threads. For SCHED_FIFO and SCHED_RR, the only required
+ *   member of the sched_param structure is the priority sched_priority.
  *
+ *   The pthread_getschedparam() function will retrieve the scheduling policy
+ *   and scheduling parameters for the thread whose thread ID is given by
+ *   'thread' and will store those values in 'policy' and 'param',
+ *   respectively. The priority value returned from pthread_getschedparam()
+ *   will be the value specified by the most recent pthread_setschedparam(),
+ *   pthread_setschedprio(), or pthread_create() call affecting the target
+ *   thread. It will not reflect any temporary adjustments to its priority (such
+ *   as might result of any priority inheritance, for example).
+ *
+ *   The policy parameter may have the value SCHED_FIFO, or SCHED_RR
+ *   (SCHED_OTHER and SCHED_SPORADIC, in particular, are not supported).
+ *   The SCHED_FIFO and SCHED_RR policies will have a single scheduling
+ *   parameter, sched_priority.
+*
  * Parameters:
- *   thread
- *   policy
- *   param
+ *   thread - The ID of thread whose scheduling parameters will be queried.
+ *   policy - The location to store the thread's scheduling policy.
+ *   param  - The location to store the thread's priority.
  *
  * Return Value:
- *   0 if successful.  Otherwise, an error code.
+ *   0 if successful.  Otherwise, the error code ESRCH if the value specified
+ *   by thread does not refer to an existing thread.
  *
  * Assumptions:
  *
- ************************************************************/
+ ****************************************************************************/
 
 int pthread_getschedparam(pthread_t thread, int *policy,
                           struct sched_param *param)
diff --git a/nuttx/sched/pthread_setschedparam.c b/nuttx/sched/pthread_setschedparam.c
index bb0435aa0..32e5326f1 100644
--- a/nuttx/sched/pthread_setschedparam.c
+++ b/nuttx/sched/pthread_setschedparam.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * pthread_setschedparam.c
  *
  *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <sys/types.h>
 #include <pthread.h>
@@ -44,54 +44,96 @@
 #include <debug.h>
 #include "pthread_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Definitions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Type Declarations
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Variables
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Variables
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Public Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Function:  pthread_setschedparam
  *
  * Description:
- *   Set thread scheduling parameters.
+ *   The pthread_setschedparam() functions will set the scheduling policy and
+ *   parameters of threads. For SCHED_FIFO and SCHED_RR, the only required
+ *   member of the sched_param structure is the priority sched_priority.
+ *
+ *   The pthread_setschedparam() function will set the scheduling policy and
+ *   associated scheduling parameters for the thread whose thread ID is
+ *   given by 'thread' to the policy and associated parameters provided in
+ *   'policy' and 'param', respectively.
+ *
+ *   The policy parameter may have the value SCHED_FIFO, or SCHED_RR
+ *   (SCHED_OTHER and SCHED_SPORADIC, in particular, are not supported).
+ *   The SCHED_FIFO and SCHED_RR policies will have a single scheduling
+ *   parameter, sched_priority.
+ *
+ *   If the pthread_setschedparam() function fails, the scheduling parameters
+ *   will not be changed for the target thread.
  *
  * Parameters:
- *   thread
- *   policy
- *   param
+ *   thread - The ID of thread whose scheduling parameters will be modified.
+ *   policy - The new scheduling policy of the thread.  Either SCHED_FIFO or
+ *            SCHED_RR. SCHED_OTHER and SCHED_SPORADIC are not supported.
+ *   param  - Provides the new priority of the thread.
  *
  * Return Value:
- *   0 if successful.  Otherwise, an error code.
+ *   0 if successful.  Otherwise, an error code identifying the cause of the
+ *   failure:
+ *
+ *   EINVAL  The value specified by 'policy' or one of the scheduling parameters
+ *           associated with the scheduling policy 'policy' is invalid.
+ *   ENOTSUP An attempt was made to set the policy or scheduling parameters
+ *           to an unsupported value (SCHED_OTHER and SCHED_SPORADIC in
+ *           particular are not supported)
+ *   EPERM   The caller does not have the appropriate permission to set either
+ *           the scheduling parameters or the scheduling policy of the
+ *           specified thread. Or, the implementation does not allow the
+ *           application to modify one of the parameters to the value
+ *           specified.
+ *   ESRCH   The value specified by thread does not refer to a existing thread.
  *
  * Assumptions:
  *
- ************************************************************/
+ ****************************************************************************/
 
 int pthread_setschedparam(pthread_t thread, int policy,
                           const struct sched_param *param)
 {
+  int ret;
+
   dbg("thread ID=%d policy=%d param=0x%p\n", thread, policy, param);
 
+  /* Set the errno to some non-zero value (failsafe) */
+
+  *get_errno_ptr() = EINVAL;
+
   /* Let sched_setscheduler do all of the work */
 
-  return sched_setscheduler((pid_t)thread, policy, param);
-}
+  ret = sched_setscheduler((pid_t)thread, policy, param);
+  if (ret != OK)
+    {
+      /* If sched_setscheduler() fails, return the errno */
+
+      ret = *get_errno_ptr();
+    }
+  return ret;
+ }
diff --git a/nuttx/sched/sched_setparam.c b/nuttx/sched/sched_setparam.c
index 30978b02e..7ee22ffb6 100644
--- a/nuttx/sched/sched_setparam.c
+++ b/nuttx/sched/sched_setparam.c
@@ -40,6 +40,7 @@
 #include <nuttx/config.h>
 #include <sys/types.h>
 #include <sched.h>
+#include <errno.h>
 #include <nuttx/arch.h>
 #include <nuttx/os_external.h>
 #include "os_internal.h"
@@ -90,14 +91,13 @@
  *      SCHED_PRIORITY_MIN through SCHED_PRIORITY_MAX.
  *
  * Return Value:
- *    OK if successful, otherwise ERROR.  This function can
- *    fail for the following reasons:
+ *   On success, sched_setparam() returns 0 (OK). On error, -1
+ *  (ERROR) is returned, and errno is set appropriately.
  *
- *    (1) parm is NULL or parm->sched_priority is out of
- *        range.
- *    (2) pid does not correspond to any task.
- *
- *    (errno is not set).
+ *  EINVAL The parameter 'param' is invalid or does not make
+ *         sense for the current scheduling policy.
+ *  EPERM  The calling task does not have appropriate privileges.
+ *  ESRCH  The task whose ID is pid could not be found.
  *
  * Assumptions:
  *
@@ -110,7 +110,6 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
   tstate_t   task_state;
   irqstate_t saved_state;
   int        sched_priority = param->sched_priority;
-  int        ret = 0;
 
   /* Verify that the requested priority is in the valid range */
 
@@ -118,6 +117,7 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
       param->sched_priority < SCHED_PRIORITY_MIN || 
       param->sched_priority > SCHED_PRIORITY_MAX)
     {
+      *get_errno_ptr() = EINVAL;
       return ERROR;
     }
 
@@ -144,6 +144,7 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
         {
           /* No task with this pid was found */
 
+          *get_errno_ptr() = ESRCH;
           sched_unlock();
           return ERROR;
         }
@@ -266,5 +267,5 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
 
   irqrestore(saved_state);
   sched_unlock();
-  return ret;
+  return OK;
 }