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-rw-r--r--nuttx/sched/group_create.c276
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diff --git a/nuttx/sched/group_create.c b/nuttx/sched/group_create.c
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+/*****************************************************************************
+ * 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_find(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 _TCB *tcb)
+{
+ int ret;
+
+ DEBUGASSERT(tcb && !tcb->group);
+
+ /* Allocate the group structure and assign it to the TCB */
+
+ tcb->group = (FAR struct task_group_s *)kzalloc(sizeof(struct task_group_s));
+ if (!tcb->group)
+ {
+ return -ENOMEM;
+ }
+
+ /* 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(tcb->group);
+#endif
+
+ /* Duplicate the parent tasks envionment */
+
+ ret = env_dup(tcb->group);
+ if (ret < 0)
+ {
+ kfree(tcb->group);
+ tcb->group = NULL;
+ return ret;
+ }
+
+ 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 _TCB *tcb)
+{
+ FAR struct task_group_s *group;
+#ifdef HAVE_GROUP_MEMBERS
+ irqstate_t flags;
+#endif
+
+ DEBUGASSERT(tcb && tcb->group);
+ group = tcb->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)
+ {
+ free(group);
+ return -ENOMEM;
+ }
+
+ /* Assign the PID of this new task as a member of the group*/
+
+ group->tg_members[0] = tcb->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
+
+ group->tg_nmembers = 1; /* Number of members in the group */
+ return OK;
+}
+
+#endif /* HAVE_TASK_GROUP */
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