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px4-firmware/nuttx/sched/task_setup.c

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/****************************************************************************
* sched/task_setup.c
*
* Copyright (C) 2007-2012 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 <sys/types.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include "os_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/* This is the name for un-named tasks */
static const char g_noname[] = "<noname>";
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int task_assignpid(FAR _TCB* tcb);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: task_assignpid
*
* Description:
* This function assigns the next unique task ID to a task.
*
* Inputs:
* tcb - TCB of task
*
* Return:
* OK on success; ERROR on failure (errno is not set)
*
****************************************************************************/
static int task_assignpid(FAR _TCB *tcb)
{
pid_t next_pid;
int hash_ndx;
int tries;
/* Disable pre-emption. This should provide sufficient protection
* for the following operation.
*/
(void)sched_lock();
/* We'll try every allowable pid */
for (tries = 0; tries < CONFIG_MAX_TASKS; tries++)
{
/* Get the next process ID candidate */
next_pid = ++g_lastpid;
/* Verify that the next_pid is in the valid range */
if (next_pid <= 0)
{
g_lastpid = 1;
next_pid = 1;
}
/* Get the hash_ndx associated with the next_pid */
hash_ndx = PIDHASH(next_pid);
/* Check if there is a (potential) duplicate of this pid */
if (!g_pidhash[hash_ndx].tcb)
{
g_pidhash[hash_ndx].tcb = tcb;
g_pidhash[hash_ndx].pid = next_pid;
tcb->pid = next_pid;
(void)sched_unlock();
return OK;
}
}
/* If we get here, then the g_pidhash[] table is completely full.
* We cannot allow another task to be started.
*/
(void)sched_unlock();
return ERROR;
}
/****************************************************************************
* Name: task_dupdspace
*
* Description:
* When a new task or thread is created from a PIC module, then that
* module (probably) intends the task or thread to execute in the same
* D-Space. This function will duplicate the D-Space for that purpose.
*
* Parameters:
* tcb - The TCB of the new task.
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
#ifdef CONFIG_PIC
static inline void task_dupdspace(FAR _TCB *tcb)
{
FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
if (rtcb->dspace != NULL)
{
/* Copy the D-Space structure reference and increment the reference
* count on the memory. The D-Space memory will persist until the
* last thread exits (see sched_releasetcb()).
*/
tcb->dspace = rtcb->dspace;
tcb->dspace->crefs++;
}
}
#else
# define task_dupdspace(tcb)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: task_schedsetup
*
* Description:
* This functions initializes a Task Control Block (TCB) in preparation
* for starting a new thread.
*
* task_schedsetup() is called from task_init(), task_start(), and
* pthread_create();
*
* Input Parameters:
* tcb - Address of the new task's TCB
* priority - Priority of the new task
* entry - Entry point of a new task
* main - Application start point of the new task
* type - Type of the new thread: task, pthread, or kernel thread
*
* Return Value:
* OK on success; ERROR on failure.
*
* This function can only failure is it is unable to assign a new, unique
* task ID to the TCB (errno is not set).
*
****************************************************************************/
int task_schedsetup(FAR _TCB *tcb, int priority, start_t start, main_t main)
{
int ret;
/* Assign a unique task ID to the task. */
ret = task_assignpid(tcb);
if (ret == OK)
{
/* Save task priority and entry point in the TCB */
tcb->init_priority = (uint8_t)priority;
tcb->sched_priority = (uint8_t)priority;
#ifdef CONFIG_PRIORITY_INHERITANCE
tcb->base_priority = (uint8_t)priority;
#endif
tcb->start = start;
tcb->entry.main = main;
/* exec() and pthread_create() inherit the signal mask of the
* parent thread. I suppose that task_create() should as well.
*/
#ifndef CONFIG_DISABLE_SIGNALS
(void)sigprocmask(SIG_SETMASK, NULL, &tcb->sigprocmask);
#endif
/* Initialize the task state. It does not get a valid state
* until it is activated.
*/
tcb->task_state = TSTATE_TASK_INVALID;
/* Clone the parent tasks D-Space (if it was running PIC). This
* must be done before calling up_initial_state() so that the
* state setup will take the PIC address base into account.
*/
task_dupdspace(tcb);
/* Initialize the processor-specific portion of the TCB */
up_initial_state(tcb);
/* Add the task to the inactive task list */
sched_lock();
dq_addfirst((FAR dq_entry_t*)tcb, (dq_queue_t*)&g_inactivetasks);
tcb->task_state = TSTATE_TASK_INACTIVE;
sched_unlock();
}
return ret;
}
/****************************************************************************
* Name: task_argsetup
*
* Description:
* This functions sets up parameters in the Task Control
* Block (TCB) in preparation for starting a new thread.
*
* task_argsetup() is called only from task_init() and
* task_start() to create a new task. Argumens are
* cloned via strdup.
*
* Input Parameters:
* tcb - Address of the new task's TCB
* name - Name of the new task (not used)
* argv - A pointer to an array of input parameters.
* Up to CONFIG_MAX_TASK_ARG parameters may be
* provided. If fewer than CONFIG_MAX_TASK_ARG
* parameters are passed, the list should be
* terminated with a NULL argv[] value.
* If no parameters are required, argv may be NULL.
*
* Return Value:
* OK
*
****************************************************************************/
int task_argsetup(FAR _TCB *tcb, const char *name, const char *argv[])
{
int i;
#if CONFIG_TASK_NAME_SIZE > 0
/* Give a name to the unnamed tasks */
if (!name)
{
name = (char *)g_noname;
}
/* Copy the name into the TCB */
strncpy(tcb->name, name, CONFIG_TASK_NAME_SIZE);
/* Save the name as the first argument */
tcb->argv[0] = tcb->name;
#else
/* Save the name as the first argument */
tcb->argv[0] = (char *)g_noname;
#endif /* CONFIG_TASK_NAME_SIZE */
/* For tasks, the life of the argument must be as long as
* the life of the task and the arguments must be strings.
* So for tasks, we have to to dup the strings.
*
* The first NULL argument terminates the list of
* arguments. The argv pointer may be NULL if no
* parameters are passed.
*/
i = 1;
if (argv)
{
for (; i < CONFIG_MAX_TASK_ARGS+1 && argv[i-1]; i++)
{
tcb->argv[i] = strdup(argv[i-1]);
}
}
/* Nullify any unused argument storage */
for (; i < CONFIG_MAX_TASK_ARGS+1; i++)
{
tcb->argv[i] = NULL;
}
return OK;
}
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