/*****************************************************************************
* sched/group_create.c
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 <nuttx/config.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include "group_internal.h"
#include "env_internal.h"
#ifdef HAVE_TASK_GROUP
/*****************************************************************************
* Pre-processor Definitions
*****************************************************************************/
/* Is this worth making a configuration option? */
#define GROUP_INITIAL_MEMBERS 4
/*****************************************************************************
* Private Types
*****************************************************************************/
/*****************************************************************************
* Private Data
*****************************************************************************/
/* This is counter that is used to generate unique task group IDs */
#ifdef HAVE_GROUP_MEMBERS
static gid_t g_gidcounter;
#endif
/*****************************************************************************
* Public Data
*****************************************************************************/
/* This is the head of a list of all group members */
#ifdef HAVE_GROUP_MEMBERS
FAR struct task_group_s *g_grouphead;
#endif
/*****************************************************************************
* Private Functions
*****************************************************************************/
/*****************************************************************************
* Name: group_assigngid
*
* Description:
* Create a unique group ID.
*
* Parameters:
* tcb - The tcb in need of the task group.
*
* Return Value:
* None
*
* Assumptions:
* Called during task creation in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
void group_assigngid(FAR struct task_group_s *group)
{
irqstate_t flags;
gid_t gid;
/* Pre-emption should already be enabled, but lets be paranoid careful */
sched_lock();
/* Loop until we create a unique ID */
for (;;)
{
/* Increment the ID counter. This is global data so be extra paraoid. */
flags = irqsave();
gid = ++g_gidcounter;
/* Check for overflow */
if (gid <= 0)
{
g_gidcounter = 1;
irqrestore(flags);
}
else
{
/* Does a task group with this ID already exist? */
irqrestore(flags);
if (group_findbygid(gid) == NULL)
{
/* Now assign this ID to the group and return */
group->tg_gid = gid;
sched_unlock();
return;
}
}
}
}
#endif /* HAVE_GROUP_MEMBERS */
/*****************************************************************************
* Public Functions
*****************************************************************************/
/*****************************************************************************
* Name: group_allocate
*
* Description:
* Create and a new task group structure for the specified TCB. This
* function is called as part of the task creation sequence. The structure
* allocated and zered, but otherwise uninitialized. The full creation
* of the group of a two step process: (1) First, this function allocates
* group structure early in the task creation sequence in order to provide a
* group container, then (2) group_initialize() is called to set up the
* group membership.
*
* Parameters:
* tcb - The tcb in need of the task group.
*
* Return Value:
* 0 (OK) on success; a negated errno value on failure.
*
* Assumptions:
* Called during task creation in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
int group_allocate(FAR struct task_tcb_s *tcb)
{
FAR struct task_group_s *group;
int ret;
DEBUGASSERT(tcb && !tcb->cmn.group);
/* Allocate the group structure and assign it to the TCB */
group = (FAR struct task_group_s *)kzalloc(sizeof(struct task_group_s));
if (!group)
{
return -ENOMEM;
}
#if CONFIG_NFILE_STREAMS > 0 && defined(CONFIG_NUTTX_KERNEL) && \
defined(CONFIG_MM_KERNEL_HEAP)
/* In a flat, single-heap build. The stream list is allocated with the
* group structure. But in a kernel build with a kernel allocator, it
* must be separately allocated using a user-space allocator.
*/
group->tg_streamlist = (FAR struct streamlist *)
kuzalloc(sizeof(struct streamlist));
if (!group->tg_streamlist)
{
kfree(group);
return -ENOMEM;
}
#endif
/* Attach the group to the TCB */
tcb->cmn.group = group;
/* Assign the group a unique ID. If g_gidcounter were to wrap before we
* finish with task creation, that would be a problem.
*/
#ifdef HAVE_GROUP_MEMBERS
group_assigngid(group);
#endif
/* Duplicate the parent tasks envionment */
ret = env_dup(group);
if (ret < 0)
{
#if CONFIG_NFILE_STREAMS > 0 && defined(CONFIG_NUTTX_KERNEL) && \
defined(CONFIG_MM_KERNEL_HEAP)
kufree(group->tg_streamlist);
#endif
kfree(group);
tcb->cmn.group = NULL;
return ret;
}
/* Initialize the pthread join semaphore */
#ifndef CONFIG_DISABLE_PTHREAD
(void)sem_init(&group->tg_joinsem, 0, 1);
#endif
return OK;
}
/*****************************************************************************
* Name: group_initialize
*
* Description:
* Add the task as the initial member of the group. The full creation of
* the group of a two step process: (1) First, this group structure is
* allocated by group_allocate() early in the task creation sequence, then
* (2) this function is called to set up the initial group membership.
*
* Parameters:
* tcb - The tcb in need of the task group.
*
* Return Value:
* 0 (OK) on success; a negated errno value on failure.
*
* Assumptions:
* Called during task creation in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
int group_initialize(FAR struct task_tcb_s *tcb)
{
FAR struct task_group_s *group;
#ifdef HAVE_GROUP_MEMBERS
irqstate_t flags;
#endif
DEBUGASSERT(tcb && tcb->cmn.group);
group = tcb->cmn.group;
#ifdef HAVE_GROUP_MEMBERS
/* Allocate space to hold GROUP_INITIAL_MEMBERS members of the group */
group->tg_members = (FAR pid_t *)kmalloc(GROUP_INITIAL_MEMBERS*sizeof(pid_t));
if (!group->tg_members)
{
kfree(group);
return -ENOMEM;
}
/* Assign the PID of this new task as a member of the group. */
group->tg_members[0] = tcb->cmn.pid;
/* Initialize the non-zero elements of group structure and assign it to
* the tcb.
*/
group->tg_mxmembers = GROUP_INITIAL_MEMBERS; /* Number of members in allocation */
/* Add the initialized entry to the list of groups */
flags = irqsave();
group->flink = g_grouphead;
g_grouphead = group;
irqrestore(flags);
#endif
/* Save the ID of the main task within the group of threads. This needed
* for things like SIGCHILD. It ID is also saved in the TCB of the main
* task but is also retained in the group which may persist after the main
* task has exited.
*/
#if !defined(CONFIG_DISABLE_PTHREAD) && defined(CONFIG_SCHED_HAVE_PARENT)
group->tg_task = tcb->cmn.pid;
#endif
/* Mark that there is one member in the group, the main task */
group->tg_nmembers = 1;
return OK;
}
#endif /* HAVE_TASK_GROUP */
