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incubator-nuttx/sched/task/task_setup.c

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/****************************************************************************
* sched/task/task_setup.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <ctype.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/signal.h>
#include <nuttx/tls.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 Functions
****************************************************************************/
/****************************************************************************
* Name: nxtask_assign_pid
*
* Description:
* This function assigns the next unique task ID to a task.
*
* Input Parameters:
* tcb - TCB of task
*
* Returned Value:
* OK on success; ERROR on failure (errno is not set)
*
****************************************************************************/
static int nxtask_assign_pid(FAR struct tcb_s *tcb)
{
FAR struct tcb_s **pidhash;
irqstate_t flags;
pid_t next_pid;
int hash_ndx;
void *temp;
int i;
/* NOTE:
* ERROR means that the g_pidhash[] table is completely full.
* We cannot allow another task to be started.
*/
/* We'll try every allowable pid */
retry:
/* Protect the following operation with a critical section
* because g_pidhash is accessed from an interrupt context
*/
flags = enter_critical_section();
/* Get the next process ID candidate */
next_pid = g_lastpid + 1;
for (i = 0; i < g_npidhash; i++)
{
/* Verify that the next_pid is in the valid range */
if (next_pid <= 0)
{
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])
{
/* Assign this PID to the task */
g_pidhash[hash_ndx] = tcb;
tcb->pid = next_pid;
g_lastpid = next_pid;
leave_critical_section(flags);
return OK;
}
next_pid++;
}
/* If we get here, then the g_pidhash[] table is completely full.
* We will alloc new space and copy original g_pidhash to it to
* expand space.
*/
temp = g_pidhash;
/* Calling malloc in a critical section may cause thread switching.
* Here we check whether other threads have applied successfully,
* and if successful, return directly
*/
leave_critical_section(flags);
pidhash = kmm_zalloc(g_npidhash * 2 * sizeof(*pidhash));
if (pidhash == NULL)
{
return -ENOMEM;
}
/* Handle conner case: context siwtch happened when kmm_malloc */
flags = enter_critical_section();
if (temp != g_pidhash)
{
leave_critical_section(flags);
kmm_free(pidhash);
goto retry;
}
g_npidhash *= 2;
/* All original pid and hash_ndx are mismatch,
* so we need to rebuild their relationship
*/
for (i = 0; i < g_npidhash / 2; i++)
{
if (g_pidhash[i] == NULL)
{
/* If the pid is not used, skip it.
* This may be triggered when a context switch occurs
* during zalloc and a thread is destroyed.
*/
continue;
}
hash_ndx = PIDHASH(g_pidhash[i]->pid);
DEBUGASSERT(pidhash[hash_ndx] == NULL);
pidhash[hash_ndx] = g_pidhash[i];
}
/* Release resource for original g_pidhash, using new g_pidhash */
g_pidhash = pidhash;
leave_critical_section(flags);
kmm_free(temp);
/* Let's try every allowable pid again */
goto retry;
}
/****************************************************************************
* Name: nxtask_inherit_affinity
*
* Description:
* exec(), task_create(), and vfork() all inherit the affinity mask from
* the parent thread. This is the default for pthread_create() as well
* but the affinity mask can be specified in the pthread attributes as
* well. pthread_setup() will have to fix up the affinity mask in this
* case.
*
* Input 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 assigned task
* list for the current CPU.
*
****************************************************************************/
#ifdef CONFIG_SMP
static inline void nxtask_inherit_affinity(FAR struct tcb_s *tcb)
{
FAR struct tcb_s *rtcb = this_task();
tcb->affinity = rtcb->affinity;
}
#else
# define nxtask_inherit_affinity(tcb)
#endif
/****************************************************************************
* Name: nxtask_save_parent
*
* Description:
* Save the task ID of the parent task in the child task's group and
* allocate a child status structure to catch the child task's exit
* status.
*
* Input 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 nxtask_save_parent(FAR struct tcb_s *tcb, uint8_t ttype)
{
DEBUGASSERT(tcb != NULL && tcb->group != NULL);
/* Only newly created tasks (and kernel threads) have parents. None of
* this logic applies to pthreads with reside in the same group as the
* parent and share that same child/parent relationships.
*/
#ifndef CONFIG_DISABLE_PTHREAD
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
#endif
{
/* Get the TCB of the parent task. In this case, the calling task. */
FAR struct tcb_s *rtcb = this_task();
DEBUGASSERT(rtcb != NULL && rtcb->group != NULL);
/* Save the PID of the parent tasks' task group in the child's task
* group. Copy the ID from the parent's task group structure to
* child's task group.
*/
tcb->group->tg_ppid = rtcb->group->tg_pid;
#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_find_child(rtcb->group, tcb->pid);
DEBUGASSERT(child == NULL);
if (child == NULL)
{
/* Allocate a new status structure */
child = group_alloc_child();
}
/* Did we successfully find/allocate the child status structure? */
DEBUGASSERT(child != NULL);
if (child != NULL)
{
/* Yes.. Initialize the structure */
child->ch_flags = ttype;
child->ch_pid = tcb->pid;
child->ch_status = 0;
/* Add the entry into the group's list of children */
group_add_child(rtcb->group, child);
}
}
#else /* CONFIG_SCHED_CHILD_STATUS */
/* Child status is not retained. Simply keep track of the number
* child tasks created.
*/
DEBUGASSERT(rtcb->group->tg_nchildren < UINT16_MAX);
rtcb->group->tg_nchildren++;
#endif /* CONFIG_SCHED_CHILD_STATUS */
}
}
#else
# define nxtask_save_parent(tcb,ttype)
#endif
/****************************************************************************
* Name: nxtask_dup_dspace
*
* 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.
*
* Input 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 nxtask_dup_dspace(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 nxsched_release_tcb()).
*/
tcb->dspace = rtcb->dspace;
tcb->dspace->crefs++;
}
}
#else
# define nxtask_dup_dspace(tcb)
#endif
/****************************************************************************
* Name: nxthread_setup_scheduler
*
* Description:
* This functions initializes the common portions of the Task Control Block
* (TCB) in preparation for starting a new thread.
*
* nxthread_setup_scheduler() is called from nxtask_setup_scheduler() and
* pthread_setup_scheduler().
*
* 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
*
* Returned 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 nxthread_setup_scheduler(FAR struct tcb_s *tcb, int priority,
start_t start, CODE void *entry,
uint8_t ttype)
{
FAR struct tcb_s *rtcb = this_task();
int ret;
/* Assign a unique task ID to the task. */
ret = nxtask_assign_pid(tcb);
if (ret == OK)
{
/* Save task priority and entry point in the TCB */
tcb->sched_priority = (uint8_t)priority;
tcb->init_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;
/* Set the appropriate scheduling policy in the TCB */
tcb->flags &= ~TCB_FLAG_POLICY_MASK;
#if CONFIG_RR_INTERVAL > 0
tcb->flags |= TCB_FLAG_SCHED_RR;
tcb->timeslice = MSEC2TICK(CONFIG_RR_INTERVAL);
#else
tcb->flags |= TCB_FLAG_SCHED_FIFO;
#endif
/* Save the task ID of the parent task in the TCB and allocate
* a child status structure.
*/
nxtask_save_parent(tcb, ttype);
#ifdef CONFIG_SMP
/* exec(), task_create(), and vfork() all inherit the affinity mask
* from the parent thread. This is the default for pthread_create()
* as well but the affinity mask can be specified in the pthread
* attributes as well. pthread_create() will have to fix up the
* affinity mask in this case.
*/
nxtask_inherit_affinity(tcb);
#endif
/* exec(), pthread_create(), task_create(), and vfork() all
* inherit the signal mask of the parent thread.
*/
tcb->sigprocmask = rtcb->sigprocmask;
/* 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.
*/
nxtask_dup_dspace(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, list_inactivetasks());
tcb->task_state = TSTATE_TASK_INACTIVE;
sched_unlock();
}
return ret;
}
/****************************************************************************
* Name: nxtask_setup_name
*
* Description:
* Assign the task name.
*
* Input Parameters:
* tcb - Address of the new task's TCB
* name - Name of the new task
*
* Returned Value:
* None
*
****************************************************************************/
#if CONFIG_TASK_NAME_SIZE > 0
static void nxtask_setup_name(FAR struct task_tcb_s *tcb,
FAR const char *name)
{
FAR char *dst = tcb->cmn.name;
int i;
/* Copy the name into the TCB */
for (i = 0; i < CONFIG_TASK_NAME_SIZE; i++)
{
char c = *name++;
if (c == '\0')
{
break;
}
*dst++ = isspace(c) ? '_' : c;
}
*dst = '\0';
}
#else
# define nxtask_setup_name(t,n)
#endif /* CONFIG_TASK_NAME_SIZE */
/****************************************************************************
* Name: nxtask_setup_stackargs
*
* Description:
* This functions is called only from nxtask_setup_arguments() 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
* name - Name of the new task
* argv - A pointer to an array of input parameters. The array should be
* terminated with a NULL argv[] value. If no parameters are
* required, argv may be NULL.
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure.
*
****************************************************************************/
static int nxtask_setup_stackargs(FAR struct task_tcb_s *tcb,
FAR const char *name,
FAR char * const argv[])
{
FAR char **stackargv;
FAR char *str;
size_t strtablen;
size_t argvlen;
int nbytes;
int argc;
int i;
/* 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 != NULL)
{
/* 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);
DEBUGASSERT(strtablen < tcb->cmn.adj_stack_size);
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.
*/
DEBUGASSERT(argc <= MAX_STACK_ARGS);
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;
strlcpy(str, name, strtablen);
str += nbytes;
strtablen -= 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;
strlcpy(str, argv[i], strtablen);
str += nbytes;
strtablen -= nbytes;
}
/* Put a terminator entry at the end of the argv[] array. Then save the
* argv[] array pointer in the TCB where it will be recovered later by
* nxtask_start().
*/
stackargv[argc + 1] = NULL;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxtask_setup_scheduler
*
* Description:
* This functions initializes a Task Control Block (TCB) in preparation
* for starting a new task.
*
* nxtask_setup_scheduler() is called from nxtask_init() and
* nxtask_start().
*
* Input Parameters:
* tcb - Address of the new task's TCB
* priority - Priority of the new task
* start - Start-up function (probably nxtask_start())
* main - Application start point of the new task
* ttype - Type of the new thread: task or kernel thread
*
* Returned 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 nxtask_setup_scheduler(FAR struct task_tcb_s *tcb, int priority,
start_t start, main_t main, uint8_t ttype)
{
/* Perform common thread setup */
return nxthread_setup_scheduler((FAR struct tcb_s *)tcb, priority,
start, (CODE void *)main, ttype);
}
/****************************************************************************
* Name: pthread_setup_scheduler
*
* Description:
* This functions initializes a Task Control Block (TCB) in preparation
* for starting a new pthread.
*
* pthread_setup_scheduler() 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
*
* Returned 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_setup_scheduler(FAR struct pthread_tcb_s *tcb, int priority,
start_t start, pthread_startroutine_t entry)
{
/* Perform common thread setup */
return nxthread_setup_scheduler((FAR struct tcb_s *)tcb, priority,
start, (CODE void *)entry,
TCB_FLAG_TTYPE_PTHREAD);
}
#endif
/****************************************************************************
* Name: nxtask_setup_arguments
*
* Description:
* This functions sets up parameters in the Task Control Block (TCB) in
* preparation for starting a new thread.
*
* nxtask_setup_arguments() is called only from nxtask_init() and
* nxtask_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. The array should be
* terminated with a NULL argv[] value. If no parameters are
* required, argv may be NULL.
*
* Returned Value:
* OK
*
****************************************************************************/
int nxtask_setup_arguments(FAR struct task_tcb_s *tcb,
FAR const char *name, FAR char * const argv[])
{
/* Give a name to the unnamed tasks */
if (!name)
{
name = (FAR char *)g_noname;
}
/* Setup the task name */
nxtask_setup_name(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 nxtask_setup_stackargs(tcb, name, argv);
}
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