说明
线程是如何创建，进程是如何创建的。
TCB基础知识
TCB主要是任务管理和group管理的内容
-
task_group_s
task_group_s {- 进程id
- 组id
- 信号资源
- 消息队列
- 文件句柄
- soket句柄
}
-
struct tcb_s
struct tcb_s
{- 任务的基本信息，名字
- wait信号量
- 信号部分
}
-
一共3种类型的TCB
define TCB_FLAG_TTYPE_TASK (0 << TCB_FLAG_TTYPE_SHIFT) /* Normal user task */
define TCB_FLAG_TTYPE_PTHREAD (1 << TCB_FLAG_TTYPE_SHIFT) /* User pthread */
define TCB_FLAG_TTYPE_KERNEL (2 << TCB_FLAG_TTYPE_SHIFT) /* Kernel thread */
struct task_group_s
{
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
struct task_group_s *flink; /* Supports a singly linked list */
gid_t tg_gid; /* The ID of this task group */
#endif
#ifdef HAVE_GROUP_MEMBERS
gid_t tg_pgid; /* The ID of the parent task group */
#endif
#if !defined(CONFIG_DISABLE_PTHREAD) && defined(CONFIG_SCHED_HAVE_PARENT)
pid_t tg_task; /* The ID of the task within the group */
#endif
uint8_t tg_flags; /* See GROUP_FLAG_* definitions */
/* Group membership ***********************************************************/
uint8_t tg_nmembers; /* Number of members in the group */
#ifdef HAVE_GROUP_MEMBERS
uint8_t tg_mxmembers; /* Number of members in allocation */
FAR pid_t *tg_members; /* Members of the group */
#endif
#if defined(CONFIG_SCHED_ATEXIT) && !defined(CONFIG_SCHED_ONEXIT)
/* atexit support ************************************************************/
# if defined(CONFIG_SCHED_ATEXIT_MAX) && CONFIG_SCHED_ATEXIT_MAX > 1
atexitfunc_t tg_atexitfunc[CONFIG_SCHED_ATEXIT_MAX];
# else
atexitfunc_t tg_atexitfunc; /* Called when exit is called. */
# endif
#endif
#ifdef CONFIG_SCHED_ONEXIT
/* on_exit support ***********************************************************/
# if defined(CONFIG_SCHED_ONEXIT_MAX) && CONFIG_SCHED_ONEXIT_MAX > 1
onexitfunc_t tg_onexitfunc[CONFIG_SCHED_ONEXIT_MAX];
FAR void *tg_onexitarg[CONFIG_SCHED_ONEXIT_MAX];
# else
onexitfunc_t tg_onexitfunc; /* Called when exit is called. */
FAR void *tg_onexitarg; /* The argument passed to the function */
# endif
#endif
#ifdef CONFIG_SCHED_HAVE_PARENT
/* Child exit status **********************************************************/
#ifdef CONFIG_SCHED_CHILD_STATUS
FAR struct child_status_s *tg_children; /* Head of a list of child status */
#endif
#ifndef HAVE_GROUP_MEMBERS
/* REVISIT: What if parent thread exits? Should use tg_pgid. */
pid_t tg_ppid; /* This is the ID of the parent thread */
#ifndef CONFIG_SCHED_CHILD_STATUS
uint16_t tg_nchildren; /* This is the number active children */
#endif
#endif /* HAVE_GROUP_MEMBERS */
#endif /* CONFIG_SCHED_HAVE_PARENT */
#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
/* waitpid support ************************************************************/
/* Simple mechanism used only when there is no support for SIGCHLD */
uint8_t tg_nwaiters; /* Number of waiters */
sem_t tg_exitsem; /* Support for waitpid */
int *tg_statloc; /* Location to return exit status */
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Pthreads *******************************************************************/
/* Pthread join Info: */
sem_t tg_joinsem; /* Mutually exclusive access to join data */
FAR struct join_s *tg_joinhead; /* Head of a list of join data */
FAR struct join_s *tg_jointail; /* Tail of a list of join data */
uint8_t tg_nkeys; /* Number pthread keys allocated */
#endif
#ifndef CONFIG_DISABLE_SIGNALS
/* POSIX Signal Control Fields ************************************************/
sq_queue_t tg_sigactionq; /* List of actions for signals */
sq_queue_t tg_sigpendingq; /* List of pending signals */
#endif
#ifndef CONFIG_DISABLE_ENVIRON
/* Environment variables ******************************************************/
size_t tg_envsize; /* Size of environment string allocation */
FAR char *tg_envp; /* Allocated environment strings */
#endif
/* PIC data space and address environments ************************************/
/* Logically the PIC data space belongs here (see struct dspace_s). The
* current logic needs review: There are differences in the away that the
* life of the PIC data is managed.
*/
#if CONFIG_NFILE_DESCRIPTORS > 0
/* File descriptors ***********************************************************/
struct filelist tg_filelist; /* Maps file descriptor to file */
#endif
#if CONFIG_NFILE_STREAMS > 0
/* FILE streams ***************************************************************/
/* In a flat, single-heap build. The stream list is allocated with this
* structure. But kernel mode with a kernel allocator, it must be separately
* allocated using a user-space allocator.
*/
#if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
defined(CONFIG_MM_KERNEL_HEAP)
FAR struct streamlist *tg_streamlist;
#else
struct streamlist tg_streamlist; /* Holds C buffered I/O info */
#endif
#endif
#if CONFIG_NSOCKET_DESCRIPTORS > 0
/* Sockets ********************************************************************/
struct socketlist tg_socketlist; /* Maps socket descriptor to socket */
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* POSIX Named Message Queue Fields *******************************************/
sq_queue_t tg_msgdesq; /* List of opened message queues */
#endif
#ifdef CONFIG_ARCH_ADDRENV
/* Address Environment ********************************************************/
group_addrenv_t tg_addrenv; /* Task group address environment */
#endif
#ifdef CONFIG_MM_SHM
/* Shared Memory **************************************************************/
struct group_shm_s tg_shm; /* Task shared memory logic */
#endif
};
#endif
struct tcb_s
{
/* Fields used to support list management *************************************/
FAR struct tcb_s *flink; /* Doubly linked list */
FAR struct tcb_s *blink;
/* Task Group *****************************************************************/
#ifdef HAVE_TASK_GROUP
FAR struct task_group_s *group; /* Pointer to shared task group data */
#endif
/* Task Management Fields *****************************************************/
pid_t pid; /* This is the ID of the thread */
start_t start; /* Thread start function */
entry_t entry; /* Entry Point into the thread */
uint8_t sched_priority; /* Current priority of the thread */
uint8_t init_priority; /* Initial priority of the thread */
#ifdef CONFIG_PRIORITY_INHERITANCE
#if CONFIG_SEM_NNESTPRIO > 0
uint8_t npend_reprio; /* Number of nested reprioritizations */
uint8_t pend_reprios[CONFIG_SEM_NNESTPRIO];
#endif
uint8_t base_priority; /* "Normal" priority of the thread */
#endif
uint8_t task_state; /* Current state of the thread */
#ifdef CONFIG_SMP
uint8_t cpu; /* CPU index if running or assigned */
cpu_set_t affinity; /* Bit set of permitted CPUs */
#endif
uint16_t flags; /* Misc. general status flags */
int16_t lockcount; /* 0=preemptable (not-locked) */
#ifdef CONFIG_SMP
int16_t irqcount; /* 0=interrupts enabled */
#endif
#ifdef CONFIG_CANCELLATION_POINTS
int16_t cpcount; /* Nested cancellation point count */
#endif
#if CONFIG_RR_INTERVAL > 0 || defined(CONFIG_SCHED_SPORADIC)
int32_t timeslice; /* RR timeslice OR Sporadic budget */
/* interval remaining */
#endif
#ifdef CONFIG_SCHED_SPORADIC
FAR struct sporadic_s *sporadic; /* Sporadic scheduling parameters */
#endif
FAR struct wdog_s *waitdog; /* All timed waits use this timer */
/* Stack-Related Fields *******************************************************/
size_t adj_stack_size; /* Stack size after adjustment */
/* for hardware, processor, etc. */
/* (for debug purposes only) */
FAR void *stack_alloc_ptr; /* Pointer to allocated stack */
/* Need to deallocate stack */
FAR void *adj_stack_ptr; /* Adjusted stack_alloc_ptr for HW */
/* The initial stack pointer value */
/* External Module Support ****************************************************/
#ifdef CONFIG_PIC
FAR struct dspace_s *dspace; /* Allocated area for .bss and .data */
#endif
/* POSIX Semaphore Control Fields *********************************************/
sem_t *waitsem; /* Semaphore ID waiting on */
/* POSIX Signal Control Fields ************************************************/
#ifndef CONFIG_DISABLE_SIGNALS
sigset_t sigprocmask; /* Signals that are blocked */
sigset_t sigwaitmask; /* Waiting for pending signals */
sq_queue_t sigpendactionq; /* List of pending signal actions */
sq_queue_t sigpostedq; /* List of posted signals */
siginfo_t sigunbinfo; /* Signal info when task unblocked */
#endif
/* POSIX Named Message Queue Fields *******************************************/
#ifndef CONFIG_DISABLE_MQUEUE
FAR struct mqueue_inode_s *msgwaitq; /* Waiting for this message queue */
#endif
/* Library related fields *****************************************************/
int pterrno; /* Current per-thread errno */
/* State save areas ***********************************************************/
/* The form and content of these fields are platform-specific. */
struct xcptcontext xcp; /* Interrupt register save area */
#if CONFIG_TASK_NAME_SIZE > 0
char name[CONFIG_TASK_NAME_SIZE+1]; /* Task name (with NUL terminator) */
#endif
};
进程创建
进程数据结构
struct task_tcb_s
{
/* Common TCB fields **********************************************************/
struct tcb_s cmn; /* Common TCB fields */
/* Task Management Fields *****************************************************/
#ifdef CONFIG_SCHED_STARTHOOK
starthook_t starthook; /* Task startup function */
FAR void starthookarg; / The argument passed to the function */
#endif
/* [Re-]start name + start-up parameters **************************************/
FAR char *argv; / Name+start-up parameters */
};
进程创建过程
static int thread_create(FAR const char *name, uint8_t ttype, int priority,
int stack_size, main_t entry,
FAR char * const argv[])
tcb = (FAR struct task_tcb_s *)kmm_zalloc(sizeof(struct task_tcb_s));
-> group_setuptaskfiles(tcb); // 处理子进程和父进程的资源问题,拷贝父进程的资源到子进程,标准输入，标准输出等
线程创建
线程数据结构
struct pthread_tcb_s
{
/* Common TCB fields **********************************************************/
struct tcb_s cmn; /* Common TCB fields */
/* Task Management Fields *****************************************************/
pthread_addr_t arg; /* Startup argument */
FAR void joininfo; / Detach-able info to support join */
/* Robust mutex support *******************************************************/
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
FAR struct pthread_mutex_s mhead; / List of mutexes held by thread */
#endif
/* Clean-up stack *************************************************************/
#ifdef CONFIG_PTHREAD_CLEANUP
/* tos - The index to the next avaiable entry at the top of the stack.
- stack - The pre-allocated clean-up stack memory.
*/
uint8_t tos;
struct pthread_cleanup_s stack[CONFIG_PTHREAD_CLEANUP_STACKSIZE];
#endif
/* POSIX Thread Specific Data *************************************************/
#if CONFIG_NPTHREAD_KEYS > 0
FAR void *pthread_data[CONFIG_NPTHREAD_KEYS];
#endif
};
线程创建过程
线程是通过1个指针共享父进程的资源，这个设计很不错
分配内存空间
ptcb = (FAR struct pthread_tcb_s *)kmm_zalloc(sizeof(struct pthread_tcb_s));
ret = group_bind(ptcb);
tcb->cmn.group = ptcb->group; //子线程的groug共享父进程的group