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nuttx/sched/task/task_setup.c

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/****************************************************************************
* sched/task/task_setup.c
*
* Copyright (C) 2007-2014 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 "sched/sched.h"
#include "pthread/pthread.h"
#include "group/group.h"
#include "task/task.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* This is an artificial limit to detect error conditions where an argv[]
* list is not properly terminated.
*/
#define MAX_STACK_ARGS 256
/****************************************************************************
* Private Data
****************************************************************************/
/* This is the name for un-named tasks */
static const char g_noname[] = "<noname>";
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int task_assignpid(FAR struct tcb_s * 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 struct tcb_s *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)
{
/* Assign this PID to the task */
g_pidhash[hash_ndx].tcb = tcb;
g_pidhash[hash_ndx].pid = next_pid;
#ifdef CONFIG_SCHED_CPULOAD
g_pidhash[hash_ndx].ticks = 0;
#endif
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_saveparent
*
* Description:
* Save the task ID of the parent task in the child task's TCB and allocate
* a child status structure to catch the child task's exit status.
*
* Parameters:
* tcb - The TCB of the new, child task.
* ttype - Type of the new thread: task, pthread, or kernel thread
*
* Returned Value:
* None
*
* Assumptions:
* The parent of the new task is the task at the head of the ready-to-run
* list.
*
****************************************************************************/
#ifdef CONFIG_SCHED_HAVE_PARENT
static inline void task_saveparent(FAR struct tcb_s *tcb, uint8_t ttype)
{
FAR struct tcb_s *rtcb = this_task();
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_SCHED_CHILD_STATUS)
DEBUGASSERT(tcb && tcb->group && rtcb->group);
#else
#endif
#ifdef HAVE_GROUP_MEMBERS
/* Save the ID of the parent tasks' task group in the child's task group.
* Do nothing for pthreads. The parent and the child are both members of
* the same task group.
*/
#ifndef CONFIG_DISABLE_PTHREAD
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
#endif
{
/* This is a new task in a new task group, we have to copy the ID from
* the parent's task group structure to child's task group.
*/
tcb->group->tg_pgid = rtcb->group->tg_gid;
}
#else
DEBUGASSERT(tcb);
/* Save the parent task's ID in the child task's TCB. I am not sure if
* this makes sense for the case of pthreads or not, but I don't think it
* is harmful in any event.
*/
tcb->ppid = rtcb->pid;
#endif
#ifdef CONFIG_SCHED_CHILD_STATUS
/* Tasks can also suppress retention of their child status by applying
* the SA_NOCLDWAIT flag with sigaction().
*/
if ((rtcb->group->tg_flags && GROUP_FLAG_NOCLDWAIT) == 0)
{
FAR struct child_status_s *child;
/* Make sure that there is not already a structure for this PID in the
* parent TCB. There should not be.
*/
child = group_findchild(rtcb->group, tcb->pid);
DEBUGASSERT(!child);
if (!child)
{
/* Allocate a new status structure */
child = group_allocchild();
}
/* Did we successfully find/allocate the child status structure? */
DEBUGASSERT(child);
if (child)
{
/* Yes.. Initialize the structure */
child->ch_flags = ttype;
child->ch_pid = tcb->pid;
child->ch_status = 0;
/* Add the entry into the TCB list of children */
group_addchild(rtcb->group, child);
}
}
#else
DEBUGASSERT(rtcb->nchildren < UINT16_MAX);
rtcb->nchildren++;
#endif
}
#else
# define task_saveparent(tcb,ttype)
#endif
/****************************************************************************
* 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:
* The parent of the new task is the task at the head of the ready-to-run
* list.
*
****************************************************************************/
#ifdef CONFIG_PIC
static inline void task_dupdspace(FAR struct tcb_s *tcb)
{
FAR struct tcb_s *rtcb = this_task();
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
/****************************************************************************
* Name: thread_schedsetup
*
* Description:
* This functions initializes the common portions of the Task Control Block
* (TCB) in preparation for starting a new thread.
*
* thread_schedsetup() is called from task_schedsetup() and
* pthread_schedsetup().
*
* Input Parameters:
* tcb - Address of the new task's TCB
* priority - Priority of the new task
* start - Thread startup routine
* entry - Thread user entry point
* ttype - 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).
*
****************************************************************************/
static int thread_schedsetup(FAR struct tcb_s *tcb, int priority,
start_t start, CODE void *entry, uint8_t ttype)
{
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->sched_priority = (uint8_t)priority;
#ifdef CONFIG_PRIORITY_INHERITANCE
tcb->base_priority = (uint8_t)priority;
#endif
tcb->start = start;
tcb->entry.main = (main_t)entry;
/* Save the thread type. This setting will be needed in
* up_initial_state() is called.
*/
ttype &= TCB_FLAG_TTYPE_MASK;
tcb->flags &= ~TCB_FLAG_TTYPE_MASK;
tcb->flags |= ttype;
/* Save the task ID of the parent task in the TCB and allocate
* a child status structure.
*/
task_saveparent(tcb, ttype);
/* exec(), pthread_create(), task_create(), and vfork() all
* inherit the signal mask of the parent thread.
*/
#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, (FAR dq_queue_t *)&g_inactivetasks);
tcb->task_state = TSTATE_TASK_INACTIVE;
sched_unlock();
}
return ret;
}
/****************************************************************************
* Name: task_namesetup
*
* Description:
* Assign the task name.
*
* Input Parameters:
* tcb - Address of the new task's TCB
* name - Name of the new task
*
* Return Value:
* None
*
****************************************************************************/
#if CONFIG_TASK_NAME_SIZE > 0
static void task_namesetup(FAR struct task_tcb_s *tcb, FAR const char *name)
{
/* Give a name to the unnamed tasks */
if (!name)
{
name = (FAR char *)g_noname;
}
/* Copy the name into the TCB */
strncpy(tcb->cmn.name, name, CONFIG_TASK_NAME_SIZE);
tcb->cmn.name[CONFIG_TASK_NAME_SIZE] = '\0';
}
#else
# define task_namesetup(t,n)
#endif /* CONFIG_TASK_NAME_SIZE */
/****************************************************************************
* Name: task_stackargsetup
*
* Description:
* This functions is called only from task_argsetup() It will allocate
* space on the new task's stack and will copy the argv[] array and all
* strings to the task's stack where it is readily accessible to the
* task. Data on the stack, on the other hand, is guaranteed to be
* accessible no matter what privilege mode the task runs in.
*
* Input Parameters:
* tcb - Address of the new task's TCB
* 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:
* Zero (OK) on success; a negated errno on failure.
*
****************************************************************************/
static inline int task_stackargsetup(FAR struct task_tcb_s *tcb,
FAR char * const argv[])
{
FAR char **stackargv;
FAR const char *name;
FAR char *str;
size_t strtablen;
size_t argvlen;
int nbytes;
int argc;
int i;
/* Get the name string that we will use as the first argument */
#if CONFIG_TASK_NAME_SIZE > 0
name = tcb->cmn.name;
#else
name = (FAR const char *)g_noname;
#endif /* CONFIG_TASK_NAME_SIZE */
/* Get the size of the task name (including the NUL terminator) */
strtablen = (strlen(name) + 1);
/* Count the number of arguments and get the accumulated size of the
* argument strings (including the null terminators). The argument count
* does not include the task name in that will be in argv[0].
*/
argc = 0;
if (argv)
{
/* A NULL argument terminates the list */
while (argv[argc])
{
/* Add the size of this argument (with NUL terminator).
* Check each time if the accumulated size exceeds the
* size of the allocated stack.
*/
strtablen += (strlen(argv[argc]) + 1);
if (strtablen >= tcb->cmn.adj_stack_size)
{
return -ENAMETOOLONG;
}
/* Increment the number of args. Here is a sanity check to
* prevent running away with an unterminated argv[] list.
* MAX_STACK_ARGS should be sufficiently large that this never
* happens in normal usage.
*/
if (++argc > MAX_STACK_ARGS)
{
return -E2BIG;
}
}
}
/* Allocate a stack frame to hold argv[] array and the strings. NOTE
* that argc + 2 entries are needed: The number of arguments plus the
* task name plus a NULL argv[] entry to terminate the list.
*/
argvlen = (argc + 2) * sizeof(FAR char *);
stackargv = (FAR char **)up_stack_frame(&tcb->cmn, argvlen + strtablen);
DEBUGASSERT(stackargv != NULL);
if (stackargv == NULL)
{
return -ENOMEM;
}
/* Get the address of the string table that will lie immediately after
* the argv[] array and mark it as a null string.
*/
str = (FAR char *)stackargv + argvlen;
/* Copy the task name. Increment str to skip over the task name and its
* NUL terminator in the string buffer.
*/
stackargv[0] = str;
nbytes = strlen(name) + 1;
strcpy(str, name);
str += nbytes;
/* Copy each argument */
for (i = 0; i < argc; i++)
{
/* Save the pointer to the location in the string buffer and copy
* the argument into the buffer. Increment str to skip over the
* argument and its NUL terminator in the string buffer.
*/
stackargv[i+1] = str;
nbytes = strlen(argv[i]) + 1;
strcpy(str, argv[i]);
str += nbytes;
}
/* Put a terminator entry at the end of the argv[] array. Then save the
* argv[] arry pointer in the TCB where it will be recovered later by
* task_start().
*/
stackargv[argc + 1] = NULL;
tcb->argv = stackargv;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: task_schedsetup
*
* Description:
* This functions initializes a Task Control Block (TCB) in preparation
* for starting a new task.
*
* task_schedsetup() is called from task_init() and task_start().
*
* Input Parameters:
* tcb - Address of the new task's TCB
* priority - Priority of the new task
* start - Start-up function (probably task_start())
* main - Application start point of the new task
* ttype - Type of the new thread: task 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 struct task_tcb_s *tcb, int priority, start_t start,
main_t main, uint8_t ttype)
{
int ret;
/* Perform common thread setup */
ret = thread_schedsetup((FAR struct tcb_s *)tcb, priority, start,
(CODE void *)main, ttype);
if (ret == OK)
{
/* Save task restart priority */
tcb->init_priority = (uint8_t)priority;
}
return ret;
}
/****************************************************************************
* Name: pthread_schedsetup
*
* Description:
* This functions initializes a Task Control Block (TCB) in preparation
* for starting a new pthread.
*
* pthread_schedsetup() is called from pthread_create(),
*
* Input Parameters:
* tcb - Address of the new task's TCB
* priority - Priority of the new task
* start - Start-up function (probably pthread_start())
* entry - Entry point of the new pthread
* ttype - 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).
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PTHREAD
int pthread_schedsetup(FAR struct pthread_tcb_s *tcb, int priority, start_t start,
pthread_startroutine_t entry)
{
/* Perform common thread setup */
return thread_schedsetup((FAR struct tcb_s *)tcb, priority, start,
(CODE void *)entry, TCB_FLAG_TTYPE_PTHREAD);
}
#endif
/****************************************************************************
* 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. In the "normal" case, the argv[] array is a
* structure in the TCB, the arguments are cloned via strdup.
*
* In the kernel build case, the argv[] array and all strings are copied
* to the task's stack. This is done because the TCB (and kernel allocated
* strings) are only accessible in kernel-mode. Data on the stack, on the
* other hand, is guaranteed to be accessible no matter what mode the
* task runs in.
*
* 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 struct task_tcb_s *tcb, FAR const char *name,
FAR char * const argv[])
{
/* Setup the task name */
task_namesetup(tcb, name);
/* Copy the argv[] array and all strings are to the task's stack. Data on
* the stack is guaranteed to be accessible by the ask no matter what
* privilege mode the task runs in.
*/
return task_stackargsetup(tcb, argv);
}
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