forked from xuos/xiuos
modify nuttx bug of lack of files
This commit is contained in:
TangYiwen123
@@ -0,0 +1,496 @@
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/****************************************************************************
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* sched/task/task_vfork.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 <queue.h>
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#include <debug.h>
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#include <nuttx/sched.h>
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#include "sched/sched.h"
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#include "group/group.h"
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#include "task/task.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* vfork() requires architecture-specific support as well as waipid(). */
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#if defined(CONFIG_ARCH_HAVE_VFORK) && defined(CONFIG_SCHED_WAITPID)
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/* This is an artificial limit to detect error conditions where an argv[]
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* list is not properly terminated.
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*/
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#define MAX_VFORK_ARGS 256
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxvfork_setup_name
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*
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* Description:
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* Copy the task name.
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*
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* Input Parameters:
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* tcb - Address of the new task's TCB
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* name - Name of the new task
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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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#if CONFIG_TASK_NAME_SIZE > 0
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static inline void nxvfork_setup_name(FAR struct tcb_s *parent,
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FAR struct task_tcb_s *child)
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{
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/* Copy the name from the parent into the child TCB */
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strncpy(child->cmn.name, parent->name, CONFIG_TASK_NAME_SIZE);
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}
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#else
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# define nxvfork_setup_name(p,c)
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#endif /* CONFIG_TASK_NAME_SIZE */
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/****************************************************************************
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* Name: nxvfork_setup_stackargs
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*
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* Description:
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* Clone the task arguments in the same relative positions on the child's
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* stack.
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*
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* Input Parameters:
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* parent - Address of the parent task's TCB
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* child - Address of the child task's TCB
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno on failure.
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*
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****************************************************************************/
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static inline int nxvfork_setup_stackargs(FAR struct tcb_s *parent,
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FAR struct task_tcb_s *child)
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{
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/* Is the parent a task? or a pthread? Only tasks (and kernel threads)
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* have command line arguments.
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*/
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child->argv = NULL;
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if ((parent->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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{
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FAR struct task_tcb_s *ptcb = (FAR struct task_tcb_s *)parent;
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uintptr_t offset;
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int argc;
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/* Get the address correction */
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offset = (uintptr_t)child->cmn.adj_stack_ptr -
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(uintptr_t)parent->adj_stack_ptr;
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/* Change the child argv[] to point into its stack (instead of its
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* parent's stack).
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*/
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child->argv = (FAR char **)((uintptr_t)ptcb->argv + offset);
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/* Copy the adjusted address for each argument */
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argc = 0;
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while (ptcb->argv[argc])
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{
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uintptr_t newaddr = (uintptr_t)ptcb->argv[argc] + offset;
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child->argv[argc] = (FAR char *)newaddr;
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/* Increment the number of args. Here is a sanity check to
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* prevent running away with an unterminated argv[] list.
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* MAX_VFORK_ARGS should be sufficiently large that this never
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* happens in normal usage.
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*/
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if (++argc > MAX_VFORK_ARGS)
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{
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return -E2BIG;
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}
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}
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/* Put a terminator entry at the end of the child argv[] array. */
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child->argv[argc] = NULL;
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}
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return OK;
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}
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/****************************************************************************
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* Name: nxvfork_setup_arguments
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*
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* Description:
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* Clone the argument list from the parent to the child.
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*
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* Input Parameters:
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* parent - Address of the parent task's TCB
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* child - Address of the child task's TCB
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno on failure.
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*
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****************************************************************************/
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static inline int nxvfork_setup_arguments(FAR struct tcb_s *parent,
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FAR struct task_tcb_s *child)
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{
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/* Clone the task name */
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nxvfork_setup_name(parent, child);
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/* Adjust and copy the argv[] array. */
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return nxvfork_setup_stackargs(parent, child);
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}
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/****************************************************************************
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* Name: nxvfork_sizeof_arguments
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*
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* Description:
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* Get the parent's argument size.
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*
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* Input Parameters:
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* parent - Address of the parent task's TCB
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*
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* Return Value:
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* The parent's argument size.
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*
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****************************************************************************/
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static inline size_t nxvfork_sizeof_arguments(FAR struct tcb_s *parent)
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{
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if ((parent->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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{
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FAR struct task_tcb_s *ptcb = (FAR struct task_tcb_s *)parent;
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size_t strtablen = 0;
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int argc = 0;
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while (ptcb->argv[argc])
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{
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/* Add the size of this argument (with NUL terminator) */
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strtablen += strlen(ptcb->argv[argc++]) + 1;
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}
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/* Return the size to hold argv[] array and the strings. */
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return (argc + 1) * sizeof(FAR char *) + strtablen;
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}
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else
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{
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return 0;
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}
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}
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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_vfork
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*
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* Description:
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* The vfork() function has the same effect as fork(), except that the
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* behavior is undefined if the process created by vfork() 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 vfork(), or returns from the function in which vfork() 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 vfork() 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 vfork(). vfork() is provided in
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* architecture-specific code.
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* 2) vfork()and calls nxtask_setup_vfork().
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* 3) nxtask_setup_vfork() 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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* - 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_vfork() provides any additional operating context. up_vfork must:
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* - Allocate and initialize the stack
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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_vfork() then calls nxtask_start_vfork()
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* 6) nxtask_start_vfork() 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_vfork() 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_vfork(start_t retaddr, size_t *argsize)
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{
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FAR struct tcb_s *parent = this_task();
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FAR struct task_tcb_s *child;
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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 && argsize != NULL);
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/* Get the type of the fork'ed task (kernel or user) */
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if ((parent->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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}
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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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}
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/* Allocate a TCB for the child task. */
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child = (FAR struct task_tcb_s *)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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set_errno(ENOMEM);
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return NULL;
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}
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/* Allocate a new task group with the same privileges as the parent */
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ret = group_allocate(child, parent->flags);
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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);
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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 = parent->base_priority; /* "Normal," unboosted priority */
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#else
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priority = parent->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, parent->entry.main,
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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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/* Return the argument size */
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*argsize = nxvfork_sizeof_arguments(parent);
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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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set_errno(-ret);
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return NULL;
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}
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/****************************************************************************
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* Name: nxtask_start_vfork
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*
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* Description:
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* The vfork() function has the same effect as fork(), except that the
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* behavior is undefined if the process created by vfork() 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 vfork(), or returns from the function in which vfork() 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 vfork() 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 vfork()
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* 2) Architecture-specific code provides vfork()and calls
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* nxtask_setup_vfork().
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* 3) nxtask_setup_vfork() 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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* - 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) vfork() provides any additional operating context. vfork must:
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* - Allocate and initialize the stack
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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) vfork() then calls nxtask_start_vfork()
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* 6) nxtask_start_vfork() then executes the child thread.
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*
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* Input Parameters:
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* retaddr - The return address from vfork() where the child task
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* will be started.
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*
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* Returned Value:
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* Upon successful completion, vfork() 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_vfork(FAR struct task_tcb_s *child)
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{
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FAR struct tcb_s *parent = this_task();
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pid_t pid;
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int rc;
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int ret;
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sinfo("Starting Child TCB=%p, parent=%p\n", child, this_task());
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DEBUGASSERT(child);
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/* Duplicate the original argument list in the forked child TCB */
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ret = nxvfork_setup_arguments(parent, child);
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if (ret < 0)
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{
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nxtask_abort_vfork(child, -ret);
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return ERROR;
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}
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/* Now we have enough in place that we can join the group */
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ret = group_initialize(child);
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if (ret < 0)
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{
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nxtask_abort_vfork(child, -ret);
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return ERROR;
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}
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/* Get the assigned pid before we start the task */
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pid = (int)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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/* The child task has not yet ran because pre-emption is disabled.
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* The child task has the same priority as the parent task, so that
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* would typically be the case anyway. However, in the SMP
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* configuration, the child thread might have already ran on
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* another CPU if pre-emption were not disabled.
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*
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* It is a requirement that the parent environment be stable while
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* vfork runs; the child thread is still dependent on things in the
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* parent thread... like the pointers into parent thread's stack
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* which will still appear in the child's registers and environment.
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*
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* We assure that by waiting for the child thread to exit before
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* returning to the parent thread. NOTE that pre-emption will be
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* re-enabled while we are waiting, giving the child thread the
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* opportunity to run.
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*/
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rc = 0;
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#ifdef CONFIG_DEBUG_FEATURES
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ret = waitpid(pid, &rc, 0);
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if (ret < 0)
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{
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serr("ERROR: waitpid failed: %d\n", get_errno());
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}
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#else
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waitpid(pid, &rc, 0);
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#endif
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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_vfork
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*
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* Description:
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* Recover from any errors after nxtask_setup_vfork() 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_vfork(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, (FAR dq_queue_t *)&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_VFORK && CONFIG_SCHED_WAITPID */
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Reference in New Issue
Block a user