df30a1f8d3
1. add support to join main task
| static pthread_t self;
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| static void *join_task(void *arg)
| {
| int ret;
| ret = pthread_join(self, NULL); <--- /* Fix Task could not be joined */
| return NULL;
| }
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| int main(int argc, char *argv[])
| {
| pthread_t thread;
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| self = pthread_self();
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| pthread_create(&thread, NULL, join_task, NULL);
| sleep(1);
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| pthread_exit(NULL);
| return 0;
| }
2. Detach active thread will not alloc for additional join, just update the task flag.
3. Remove the return value waiting lock logic (data_sem),
the return value will be stored in the waiting tcb.
4. Revise the return value of pthread_join(), consistent with linux
e.g:
Joining a detached and canceled thread should return EINVAL, not ESRCH
https://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_join.html
[EINVAL]
The value specified by thread does not refer to a joinable thread.
NOTE:
This PR will not increase stack usage, but struct tcb_s will increase 32 bytes.
Signed-off-by: chao an <anchao@lixiang.com>
331 lines
10 KiB
C
331 lines
10 KiB
C
/****************************************************************************
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* sched/task/task_fork.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/wait.h>
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#include <stdint.h>
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#include <sched.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/queue.h>
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#include "sched/sched.h"
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#include "environ/environ.h"
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#include "group/group.h"
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#include "task/task.h"
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#include "tls/tls.h"
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/* fork() requires architecture-specific support as well as waipid(). */
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#ifdef CONFIG_ARCH_HAVE_FORK
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtask_setup_fork
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*
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* Description:
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* The fork() function has the same effect as posix fork(), except that the
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* behavior is undefined if the process created by fork() either modifies
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* any data other than a variable of type pid_t used to store the return
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* value from fork(), or returns from the function in which fork() was
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* called, or calls any other function before successfully calling _exit()
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* or one of the exec family of functions.
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*
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* This function provides one step in the overall fork() sequence: It
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* Allocates and initializes the child task's TCB. The overall sequence
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* is:
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*
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* 1) User code calls fork(). fork() is provided in
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* architecture-specific code.
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* 2) fork()and calls nxtask_setup_fork().
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* 3) nxtask_setup_fork() allocates and configures the child task's TCB.
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* This consists of:
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* - Allocation of the child task's TCB.
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* - Initialization of file descriptors and streams
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* - Configuration of environment variables
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* - Allocate and initialize the stack
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* - Setup the input parameters for the task.
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* - Initialization of the TCB (including call to up_initial_state())
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* 4) up_fork() provides any additional operating context. up_fork must:
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* - Initialize special values in any CPU registers that were not
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* already configured by up_initial_state()
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* 5) up_fork() then calls nxtask_start_fork()
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* 6) nxtask_start_fork() then executes the child thread.
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*
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* Input Parameters:
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* retaddr - Return address
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* argsize - Location to return the argument size
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*
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* Returned Value:
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* Upon successful completion, nxtask_setup_fork() returns a pointer to
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* newly allocated and initialized child task's TCB. NULL is returned
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* on any failure and the errno is set appropriately.
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*
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****************************************************************************/
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FAR struct task_tcb_s *nxtask_setup_fork(start_t retaddr)
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{
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FAR struct tcb_s *ptcb = this_task();
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FAR struct tcb_s *parent;
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FAR struct task_tcb_s *child;
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size_t stack_size;
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uint8_t ttype;
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int priority;
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int ret;
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DEBUGASSERT(retaddr != NULL);
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/* Get the type of the fork'ed task (kernel or user) */
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if ((ptcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_KERNEL)
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{
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/* Fork'ed from a kernel thread */
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ttype = TCB_FLAG_TTYPE_KERNEL;
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parent = ptcb;
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}
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else
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{
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/* Fork'ed from a user task or pthread */
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ttype = TCB_FLAG_TTYPE_TASK;
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if ((ptcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_TASK)
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{
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parent = ptcb;
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}
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else
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{
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parent = nxsched_get_tcb(ptcb->group->tg_pid);
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if (parent == NULL)
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{
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ret = -ENOENT;
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goto errout;
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}
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}
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}
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/* Allocate a TCB for the child task. */
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child = kmm_zalloc(sizeof(struct task_tcb_s));
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if (!child)
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{
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serr("ERROR: Failed to allocate TCB\n");
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ret = -ENOMEM;
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goto errout;
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}
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child->cmn.flags |= TCB_FLAG_FREE_TCB;
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/* Initialize the task join */
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nxtask_joininit(&child->cmn);
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/* Allocate a new task group with the same privileges as the parent */
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ret = group_initialize(child, ttype);
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if (ret < 0)
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{
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goto errout_with_tcb;
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}
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/* Duplicate the parent tasks environment */
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ret = env_dup(child->cmn.group, environ);
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if (ret < 0)
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{
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goto errout_with_tcb;
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}
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/* Associate file descriptors with the new task */
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ret = group_setuptaskfiles(child, NULL, false);
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if (ret < OK)
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{
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goto errout_with_tcb;
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}
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/* Allocate the stack for the TCB */
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stack_size = (uintptr_t)ptcb->stack_base_ptr -
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(uintptr_t)ptcb->stack_alloc_ptr + ptcb->adj_stack_size;
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ret = up_create_stack(&child->cmn, stack_size, ttype);
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if (ret < OK)
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{
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goto errout_with_tcb;
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}
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/* Setup thread local storage */
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ret = tls_dup_info(&child->cmn, parent);
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if (ret < OK)
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{
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goto errout_with_tcb;
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}
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/* Get the priority of the parent task */
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#ifdef CONFIG_PRIORITY_INHERITANCE
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priority = ptcb->base_priority; /* "Normal," unboosted priority */
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#else
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priority = ptcb->sched_priority; /* Current priority */
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#endif
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/* Initialize the task control block. This calls up_initial_state() */
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sinfo("Child priority=%d start=%p\n", priority, retaddr);
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ret = nxtask_setup_scheduler(child, priority, retaddr,
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ptcb->entry.main, ttype);
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if (ret < OK)
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{
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goto errout_with_tcb;
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}
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/* Setup to pass parameters to the new task */
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ret = nxtask_setup_arguments(child, parent->group->tg_info->ta_argv[0],
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&parent->group->tg_info->ta_argv[1]);
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if (ret < OK)
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{
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goto errout_with_tcb;
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}
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/* Now we have enough in place that we can join the group */
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group_postinitialize(child);
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sinfo("parent=%p, returning child=%p\n", parent, child);
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return child;
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errout_with_tcb:
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nxsched_release_tcb((FAR struct tcb_s *)child, ttype);
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errout:
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set_errno(-ret);
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return NULL;
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}
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/****************************************************************************
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* Name: nxtask_start_fork
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*
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* Description:
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* The fork() function has the same effect as fork(), except that the
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* behavior is undefined if the process created by fork() either modifies
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* any data other than a variable of type pid_t used to store the return
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* value from fork(), or returns from the function in which fork() was
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* called, or calls any other function before successfully calling _exit()
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* or one of the exec family of functions.
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*
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* This function provides one step in the overall fork() sequence: It
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* starts execution of the previously initialized TCB. The overall
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* sequence is:
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*
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* 1) User code calls fork()
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* 2) Architecture-specific code provides fork()and calls
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* nxtask_setup_fork().
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* 3) nxtask_setup_fork() allocates and configures the child task's TCB.
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* This consists of:
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* - Allocation of the child task's TCB.
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* - Initialization of file descriptors and streams
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* - Configuration of environment variables
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* - Allocate and initialize the stack
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* - Setup the input parameters for the task.
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* - Initialization of the TCB (including call to up_initial_state())
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* 4) fork() provides any additional operating context. fork must:
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* - Initialize special values in any CPU registers that were not
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* already configured by up_initial_state()
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* 5) fork() then calls nxtask_start_fork()
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* 6) nxtask_start_fork() then executes the child thread.
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*
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* Input Parameters:
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* child - The task_tcb_s struct instance that created by
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* nxtask_setup_fork() method
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* wait_child - whether need to wait until the child is running finished
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*
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* Returned Value:
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* Upon successful completion, fork() returns 0 to the child process and
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* returns the process ID of the child process to the parent process.
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* Otherwise, -1 is returned to the parent, no child process is created,
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* and errno is set to indicate the error.
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*
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****************************************************************************/
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pid_t nxtask_start_fork(FAR struct task_tcb_s *child)
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{
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pid_t pid;
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sinfo("Starting Child TCB=%p\n", child);
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DEBUGASSERT(child);
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/* Get the assigned pid before we start the task */
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pid = child->cmn.pid;
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/* Eliminate a race condition by disabling pre-emption. The child task
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* can be instantiated, but cannot run until we call waitpid(). This
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* assures us that we cannot miss the death-of-child signal (only
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* needed in the SMP case).
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*/
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sched_lock();
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/* Activate the task */
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nxtask_activate((FAR struct tcb_s *)child);
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sched_unlock();
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return pid;
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}
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/****************************************************************************
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* Name: nxtask_abort_fork
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*
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* Description:
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* Recover from any errors after nxtask_setup_fork() was called.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void nxtask_abort_fork(FAR struct task_tcb_s *child, int errcode)
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{
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/* The TCB was added to the active task list by nxtask_setup_scheduler() */
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dq_rem((FAR dq_entry_t *)child, &g_inactivetasks);
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/* Release the TCB */
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nxsched_release_tcb((FAR struct tcb_s *)child,
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child->cmn.flags & TCB_FLAG_TTYPE_MASK);
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set_errno(errcode);
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}
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#endif /* CONFIG_ARCH_HAVE_FORK */
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