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/****************************************************************************
* pthread_setschedparam.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* 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>
#include <sched.h>
#include <errno.h>
#include <debug.h>
#include "pthread_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: pthread_setschedparam
*
* Description:
* 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 - 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 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;
sdbg("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 */
ret = sched_setscheduler((pid_t)thread, policy, param);
if (ret != OK)
{
/* If sched_setscheduler() fails, return the errno */
ret = *get_errno_ptr();
}
return ret;
}
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