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rt-thread/components/lwp/lwp_pid.c

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/*
* Copyright (c) 2006-2025 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-10-16 zhangjun first version
* 2021-02-20 lizhirui fix warning
* 2023-06-26 shell clear ref to parent on waitpid()
* Remove recycling of lwp on waitpid() and leave it to defunct routine
* 2023-07-27 shell Move the detach of children process on parent exit to lwp_terminate.
* Make lwp_from_pid locked by caller to avoid possible use-after-free
* error
* 2023-10-27 shell Format codes of sys_exit(). Fix the data racing where lock is missed
* Add reference on pid/tid, so the resource is not freed while using.
* Add support for waitpid(options=WNOHANG)
* 2023-11-16 xqyjlj Fix the case where pid is 0
* 2023-11-17 xqyjlj add process group and session support
* 2023-11-24 shell Support of waitpid(options=WNOTRACED|WCONTINUED);
* Reimplement the waitpid with a wait queue method, and fixup problem
* with waitpid(pid=-1)/waitpid(pid=-pgid)/waitpid(pid=0) that only one
* process can be traced while waiter suspend
* 2024-01-25 shell porting to new sched API
*/
/* includes scheduler related API */
#define __RT_IPC_SOURCE__
/* for waitpid, we are compatible to GNU extension */
#define _GNU_SOURCE
#define DBG_TAG "lwp.pid"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#include "lwp_internal.h"
#include <rthw.h>
#include <rtthread.h>
#include <dfs_file.h>
#include <unistd.h>
#include <stdio.h> /* rename() */
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/statfs.h> /* statfs() */
#include <stdatomic.h>
#ifdef ARCH_MM_MMU
#include "lwp_user_mm.h"
#endif
#ifdef RT_USING_DFS_PROCFS
#include "proc.h"
#include "procfs.h"
#endif
#define PID_MAX 10000
#define PID_CT_ASSERT(name, x) \
struct assert_##name {char ary[2 * (x) - 1];}
PID_CT_ASSERT(pid_min_nr, RT_LWP_MAX_NR > 1);
PID_CT_ASSERT(pid_max_nr, RT_LWP_MAX_NR < PID_MAX);
static struct lwp_avl_struct lwp_pid_ary[RT_LWP_MAX_NR];
static struct lwp_avl_struct *lwp_pid_free_head = RT_NULL;
static int lwp_pid_ary_alloced = 0;
static struct lwp_avl_struct *lwp_pid_root = RT_NULL;
static pid_t current_pid = 0;
static struct rt_mutex pid_mtx;
static struct rt_wqueue _pid_emptyq;
/**
* @brief Initialize PID management structures
*
* @return int Always returns 0.
*/
int lwp_pid_init(void)
{
rt_wqueue_init(&_pid_emptyq);
rt_mutex_init(&pid_mtx, "pidmtx", RT_IPC_FLAG_PRIO);
return 0;
}
/**
* @brief Wait for an empty PID slot to become available
*
* @param[in] wait_flags Wait mode flags (RT_INTERRUPTIBLE, RT_KILLABLE or RT_UNINTERRUPTIBLE)
* @param[in] to Timeout value in ticks (RT_WAITING_FOREVER for no timeout)
*
* @return int Error code (0 on success, negative on error)
*/
int lwp_pid_wait_for_empty(int wait_flags, rt_tick_t to)
{
int error;
if (wait_flags == RT_INTERRUPTIBLE)
{
error = rt_wqueue_wait_interruptible(&_pid_emptyq, 0, to);
}
else
{
error = rt_wqueue_wait_killable(&_pid_emptyq, 0, to);
}
return error;
}
/**
* @brief Acquire the PID management mutex lock
*
* @note This is a blocking call that will wait indefinitely for the lock
*/
void lwp_pid_lock_take(void)
{
LWP_DEF_RETURN_CODE(rc);
rc = lwp_mutex_take_safe(&pid_mtx, RT_WAITING_FOREVER, 0);
/* should never failed */
RT_ASSERT(rc == RT_EOK);
RT_UNUSED(rc);
}
/**
* @brief Release the PID management mutex lock
*
* @note This function should be called after lwp_pid_lock_take()
*/
void lwp_pid_lock_release(void)
{
/* should never failed */
if (lwp_mutex_release_safe(&pid_mtx) != RT_EOK)
RT_ASSERT(0);
}
/**
* @brief Parameter structure for PID iteration callback
*
* @note This structure holds the callback function and context data used when
* iterating through process IDs.
*/
struct pid_foreach_param
{
/**
* @brief Callback function to execute for each PID
* @param[in] pid The process ID being processed
* @param[in,out] data User-provided context data
* @return int Operation status (0 to continue, non-zero to stop)
*/
int (*cb)(pid_t pid, void *data);
void *data; /**< User-provided context data */
};
/**
* @brief Callback function for PID iteration
*
* @param[in] node AVL tree node containing the PID
* @param[in] data User-provided parameter structure
*
* @return int Operation status (0 to continue, non-zero to stop)
*/
static int _before_cb(struct lwp_avl_struct *node, void *data)
{
struct pid_foreach_param *param = data;
pid_t pid = node->avl_key;
return param->cb(pid, param->data);
}
/**
* @brief Iterate over all process IDs
*
* @param[in] cb Callback function to execute for each PID
* @param[in] data User-provided context data
*
* @return int Error code (0 on success, negative on error)
*/
int lwp_pid_for_each(int (*cb)(pid_t pid, void *data), void *data)
{
int error;
struct pid_foreach_param buf =
{
.cb = cb,
.data = data,
};
lwp_pid_lock_take();
error = lwp_avl_traversal(lwp_pid_root, _before_cb, &buf);
lwp_pid_lock_release();
return error;
}
/**
* @brief Get the PID array
*
* @return struct lwp_avl_struct* Pointer to the PID array
*/
struct lwp_avl_struct *lwp_get_pid_ary(void)
{
return lwp_pid_ary;
}
/**
* @brief Allocates a new PID while holding the PID management lock
*
* @return pid_t The newly allocated PID, or 0 if allocation failed
*
* @note This function attempts to allocate a new process ID (PID) from either:
* 1. The free list (lwp_pid_free_head) if available
* 2. The PID array (lwp_pid_ary) if within maximum limits
*
* It then searches for an unused PID in two ranges:
* 1. From current_pid+1 to PID_MAX
* 2. From 1 to current_pid (if first search fails)
*
* The allocated PID is inserted into the PID AVL tree (lwp_pid_root)
* and current_pid is updated to the new PID.
*/
static pid_t lwp_pid_get_locked(void)
{
struct lwp_avl_struct *p;
pid_t pid = 0;
p = lwp_pid_free_head;
if (p)
{
lwp_pid_free_head = (struct lwp_avl_struct *)p->avl_right;
}
else if (lwp_pid_ary_alloced < RT_LWP_MAX_NR)
{
p = lwp_pid_ary + lwp_pid_ary_alloced;
lwp_pid_ary_alloced++;
}
if (p)
{
int found_noused = 0;
RT_ASSERT(p->data == RT_NULL);
for (pid = current_pid + 1; pid < PID_MAX; pid++)
{
if (!lwp_avl_find(pid, lwp_pid_root))
{
found_noused = 1;
break;
}
}
if (!found_noused)
{
for (pid = 1; pid <= current_pid; pid++)
{
if (!lwp_avl_find(pid, lwp_pid_root))
{
found_noused = 1;
break;
}
}
}
p->avl_key = pid;
lwp_avl_insert(p, &lwp_pid_root);
current_pid = pid;
}
return pid;
}
/**
* @brief Release a PID back to the free list while holding the PID lock
*
* @param[in] pid The process ID to release (must not be 0)
*
* @note This function removes the specified PID from the active PID tree and
* adds it to the free list. The operation is performed atomically while
* holding the PID management lock.
*/
static void lwp_pid_put_locked(pid_t pid)
{
struct lwp_avl_struct *p;
if (pid == 0)
{
return;
}
p = lwp_avl_find(pid, lwp_pid_root);
if (p)
{
p->data = RT_NULL;
lwp_avl_remove(p, &lwp_pid_root);
p->avl_right = lwp_pid_free_head;
lwp_pid_free_head = p;
}
}
#ifdef RT_USING_DFS_PROCFS
/**
* @brief Free the proc dentry for the given LWP
*
* @param[in] lwp The LWP whose proc dentry is to be freed
*/
rt_inline void _free_proc_dentry(rt_lwp_t lwp)
{
char pid_str[64] = {0};
rt_snprintf(pid_str, 64, "%d", lwp->pid);
pid_str[63] = 0;
proc_remove_dentry(pid_str, 0);
}
#else
#define _free_proc_dentry(lwp)
#endif
/**
* @brief Release a process ID and clean up associated resources
*
* @param[in,out] lwp The lightweight process whose PID should be released
*/
void lwp_pid_put(struct rt_lwp *lwp)
{
_free_proc_dentry(lwp);
lwp_pid_lock_take();
lwp_pid_put_locked(lwp->pid);
if (lwp_pid_root == AVL_EMPTY)
{
rt_wqueue_wakeup_all(&_pid_emptyq, RT_NULL);
/* refuse any new pid allocation now */
}
else
{
lwp_pid_lock_release();
}
/* reset pid field */
lwp->pid = 0;
/* clear reference */
lwp_ref_dec(lwp);
}
/**
* @brief Set the LWP for a given PID while holding the PID lock
*
* @param[in] pid The process ID to set the LWP for
* @param[in] lwp The LWP to associate with the PID
*
* @note This function associates the specified LWP with the given PID in the
* PID AVL tree. It increments the LWP's reference count and updates the
* proc filesystem entry if the PID is non-zero.
*/
static void lwp_pid_set_lwp_locked(pid_t pid, struct rt_lwp *lwp)
{
struct lwp_avl_struct *p;
p = lwp_avl_find(pid, lwp_pid_root);
if (p)
{
p->data = lwp;
lwp_ref_inc(lwp);
#ifdef RT_USING_DFS_PROCFS
if (pid)
{
proc_pid(pid);
}
#endif
}
}
/**
* @brief Close all open files for the given LWP
*
* @param[in] lwp The LWP whose files should be closed
*
* @note This function iterates through all file descriptors in the LWP's file
* descriptor table, closing each open file. It is typically called when
* an LWP is being destroyed or when the LWP is switching to a new thread.
*/
static void __exit_files(struct rt_lwp *lwp)
{
int fd = lwp->fdt.maxfd - 1;
while (fd >= 0)
{
struct dfs_file *d;
d = lwp->fdt.fds[fd];
if (d)
{
dfs_file_close(d);
fdt_fd_release(&lwp->fdt, fd);
}
fd--;
}
}
/**
* @brief Initialize the user object lock for a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object lock needs initialization
*/
void lwp_user_object_lock_init(struct rt_lwp *lwp)
{
rt_mutex_init(&lwp->object_mutex, "lwp_obj", RT_IPC_FLAG_PRIO);
}
/**
* @brief Destroy the user object lock for a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object lock needs destruction
*/
void lwp_user_object_lock_destroy(struct rt_lwp *lwp)
{
rt_mutex_detach(&lwp->object_mutex);
}
/**
* @brief Lock the user object lock for a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object lock needs locking
*/
void lwp_user_object_lock(struct rt_lwp *lwp)
{
if (lwp)
{
rt_mutex_take(&lwp->object_mutex, RT_WAITING_FOREVER);
}
else
{
RT_ASSERT(0);
}
}
/**
* @brief Unlock the user object lock for a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object lock needs unlocking
*/
void lwp_user_object_unlock(struct rt_lwp *lwp)
{
if (lwp)
{
rt_mutex_release(&lwp->object_mutex);
}
else
{
RT_ASSERT(0);
}
}
/**
* @brief Add an object to the user object list of a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object list needs updating
* @param[in] object The object to be added to the LWP's object list
*
* @return int Returns 0 on success, or -1 on failure
*/
int lwp_user_object_add(struct rt_lwp *lwp, rt_object_t object)
{
int ret = -1;
if (lwp && object)
{
lwp_user_object_lock(lwp);
if (!lwp_avl_find((avl_key_t)object, lwp->object_root))
{
struct lwp_avl_struct *node;
node = (struct lwp_avl_struct *)rt_malloc(sizeof(struct lwp_avl_struct));
if (node)
{
rt_atomic_add(&object->lwp_ref_count, 1);
node->avl_key = (avl_key_t)object;
lwp_avl_insert(node, &lwp->object_root);
ret = 0;
}
}
lwp_user_object_unlock(lwp);
}
return ret;
}
/**
* @brief Delete a node from the user object list of a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object list needs updating
* @param[in] node The node to be deleted from the LWP's object list
*
* @return rt_err_t Returns 0 on success, or -1 on failure
*/
static rt_err_t _object_node_delete(struct rt_lwp *lwp, struct lwp_avl_struct *node)
{
rt_err_t ret = -1;
rt_object_t object;
if (!lwp || !node)
{
return ret;
}
object = (rt_object_t)node->avl_key;
object->lwp_ref_count--;
if (object->lwp_ref_count == 0)
{
/* remove from kernel object list */
switch (object->type)
{
case RT_Object_Class_Semaphore:
ret = rt_sem_delete((rt_sem_t)object);
break;
case RT_Object_Class_Mutex:
ret = rt_mutex_delete((rt_mutex_t)object);
break;
case RT_Object_Class_Event:
ret = rt_event_delete((rt_event_t)object);
break;
case RT_Object_Class_MailBox:
ret = rt_mb_delete((rt_mailbox_t)object);
break;
case RT_Object_Class_MessageQueue:
ret = rt_mq_delete((rt_mq_t)object);
break;
case RT_Object_Class_Timer:
ret = rt_timer_delete((rt_timer_t)object);
break;
case RT_Object_Class_Custom:
ret = rt_custom_object_destroy(object);
break;
default:
LOG_E("input object type(%d) error", object->type);
break;
}
}
else
{
ret = 0;
}
lwp_avl_remove(node, &lwp->object_root);
rt_free(node);
return ret;
}
/**
* @brief Delete an object from the user object list of a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object list needs updating
* @param[in] object The object to be deleted from the LWP's object list
*
* @return rt_err_t Returns 0 on success, or -1 on failure
*/
rt_err_t lwp_user_object_delete(struct rt_lwp *lwp, rt_object_t object)
{
rt_err_t ret = -1;
if (lwp && object)
{
struct lwp_avl_struct *node;
lwp_user_object_lock(lwp);
node = lwp_avl_find((avl_key_t)object, lwp->object_root);
ret = _object_node_delete(lwp, node);
lwp_user_object_unlock(lwp);
}
return ret;
}
/**
* @brief Clear all objects from the user object list of a lightweight process
*
* @param[in,out] lwp The lightweight process structure whose object list needs clearing
*/
void lwp_user_object_clear(struct rt_lwp *lwp)
{
struct lwp_avl_struct *node;
lwp_user_object_lock(lwp);
while ((node = lwp_map_find_first(lwp->object_root)) != RT_NULL)
{
_object_node_delete(lwp, node);
}
lwp_user_object_unlock(lwp);
}
/**
* @brief Callback function for duplicating objects in AVL tree traversal
*
* @param[in] node The AVL tree node containing the object to duplicate
* @param[in,out] arg The destination lightweight process (cast to struct rt_lwp *)
* @return int Always returns 0 to continue traversal
*
* @note This function is used as a callback during AVL tree traversal
* to duplicate objects from one process to another
*/
static int _object_dup(struct lwp_avl_struct *node, void *arg)
{
rt_object_t object;
struct rt_lwp *dst_lwp = (struct rt_lwp *)arg;
object = (rt_object_t)node->avl_key;
lwp_user_object_add(dst_lwp, object);
return 0;
}
/**
* @brief Duplicate all objects from one lightweight process to another
*
* @param[in,out] dst_lwp The destination lightweight process structure
* @param[in] src_lwp The source lightweight process structure
*
* @note This function duplicates all objects from the source LWP to the destination LWP
* by traversing the source LWP's object list and adding each object to the destination LWP
*/
void lwp_user_object_dup(struct rt_lwp *dst_lwp, struct rt_lwp *src_lwp)
{
lwp_user_object_lock(src_lwp);
lwp_avl_traversal(src_lwp->object_root, _object_dup, dst_lwp);
lwp_user_object_unlock(src_lwp);
}
/**
* @brief Create a new lightweight process (LWP)
*
* @param[in] flags Creation flags that control LWP behavior
* - LWP_CREATE_FLAG_NOTRACE_EXEC: Don't trace exec operations
* - LWP_CREATE_FLAG_ALLOC_PID: Allocate a PID for the LWP
* - LWP_CREATE_FLAG_INIT_USPACE: Initialize user space
*
* @return Pointer to newly created LWP structure on success
* - RT_NULL on failure (pid allocation failed or user space init failed)
*/
rt_lwp_t lwp_create(rt_base_t flags)
{
pid_t pid;
rt_lwp_t new_lwp = rt_calloc(1, sizeof(struct rt_lwp));
if (new_lwp)
{
/* minimal setup of lwp object */
new_lwp->ref = 1;
#ifdef RT_USING_SMP
new_lwp->bind_cpu = RT_CPUS_NR;
#endif
new_lwp->exe_file = RT_NULL;
rt_list_init(&new_lwp->t_grp);
rt_list_init(&new_lwp->pgrp_node);
rt_list_init(&new_lwp->timer);
lwp_user_object_lock_init(new_lwp);
rt_wqueue_init(&new_lwp->wait_queue);
rt_wqueue_init(&new_lwp->waitpid_waiters);
lwp_signal_init(&new_lwp->signal);
rt_mutex_init(&new_lwp->lwp_lock, "lwp_lock", RT_IPC_FLAG_PRIO);
if (flags & LWP_CREATE_FLAG_NOTRACE_EXEC)
new_lwp->did_exec = RT_TRUE;
/* lwp with pid */
if (flags & LWP_CREATE_FLAG_ALLOC_PID)
{
lwp_pid_lock_take();
pid = lwp_pid_get_locked();
if (pid == 0)
{
lwp_user_object_lock_destroy(new_lwp);
rt_free(new_lwp);
new_lwp = RT_NULL;
LOG_E("%s: pid slot fulled", __func__);
}
else
{
new_lwp->pid = pid;
lwp_pid_set_lwp_locked(pid, new_lwp);
}
lwp_pid_lock_release();
}
rt_memset(&new_lwp->rt_rusage,0, sizeof(new_lwp->rt_rusage));
if (flags & LWP_CREATE_FLAG_INIT_USPACE)
{
rt_err_t error = lwp_user_space_init(new_lwp, 0);
if (error)
{
lwp_pid_put(new_lwp);
lwp_user_object_lock_destroy(new_lwp);
rt_free(new_lwp);
new_lwp = RT_NULL;
LOG_E("%s: failed to initialize user space", __func__);
}
}
}
LOG_D("%s(pid=%d) => %p", __func__, new_lwp ? new_lwp->pid : -1, new_lwp);
return new_lwp;
}
/**
* @brief Free all resources associated with a lightweight process (LWP)
*
* @param[in,out] lwp Lightweight process to be freed
*
* @note when reference is 0, a lwp can be released
*/
void lwp_free(struct rt_lwp* lwp)
{
rt_processgroup_t group = RT_NULL;
if (lwp == RT_NULL)
{
return;
}
/**
* Brief: Recycle the lwp when reference is cleared
*
* Note: Critical Section
* - lwp (RW. there is no other writer/reader compete with lwp_free, since
* all the reference is clear)
*/
LOG_D("lwp free: %p", lwp);
rt_free(lwp->exe_file);
group = lwp_pgrp_find(lwp_pgid_get_byprocess(lwp));
if (group)
lwp_pgrp_remove(group, lwp);
LWP_LOCK(lwp);
if (lwp->args != RT_NULL)
{
#ifndef ARCH_MM_MMU
lwp->args_length = RT_NULL;
#ifndef ARCH_MM_MPU
rt_free(lwp->args);
#endif /* not defined ARCH_MM_MPU */
#endif /* ARCH_MM_MMU */
lwp->args = RT_NULL;
}
lwp_user_object_clear(lwp);
lwp_user_object_lock_destroy(lwp);
/* free data section */
if (lwp->data_entry != RT_NULL)
{
#ifdef ARCH_MM_MMU
rt_free_align(lwp->data_entry);
#else
#ifdef ARCH_MM_MPU
rt_lwp_umap_user(lwp, lwp->text_entry, 0);
rt_lwp_free_user(lwp, lwp->data_entry, lwp->data_size);
#else
rt_free_align(lwp->data_entry);
#endif /* ARCH_MM_MPU */
#endif /* ARCH_MM_MMU */
lwp->data_entry = RT_NULL;
}
/* free text section */
if (lwp->lwp_type == LWP_TYPE_DYN_ADDR)
{
if (lwp->text_entry)
{
LOG_D("lwp text free: %p", lwp->text_entry);
#ifndef ARCH_MM_MMU
rt_free((void*)lwp->text_entry);
#endif /* not defined ARCH_MM_MMU */
lwp->text_entry = RT_NULL;
}
}
#ifdef ARCH_MM_MMU
lwp_unmap_user_space(lwp);
#endif
timer_list_free(&lwp->timer);
LWP_UNLOCK(lwp);
RT_ASSERT(lwp->lwp_lock.owner == RT_NULL);
rt_mutex_detach(&lwp->lwp_lock);
/**
* pid must have release before enter lwp_free()
* otherwise this is a data racing
*/
RT_ASSERT(lwp->pid == 0);
rt_free(lwp);
}
/**
* @brief Handle thread exit cleanup for a lightweight process
*
* @param[in,out] lwp Lightweight process containing the thread
* @param[in,out] thread Thread to be exited
*
* @note This function performs the following operations:
* - Updates process resource usage statistics (system and user time)
* - Removes thread from process sibling list
* - Handles futex robust list cleanup
* - Releases thread ID (TID)
* - Deletes the thread
* - Enters infinite loop (noreturn function)
*/
rt_inline rt_noreturn
void _thread_exit(rt_lwp_t lwp, rt_thread_t thread)
{
LWP_LOCK(lwp);
lwp->rt_rusage.ru_stime.tv_sec += thread->system_time / RT_TICK_PER_SECOND;
lwp->rt_rusage.ru_stime.tv_usec += thread->system_time % RT_TICK_PER_SECOND * (1000000 / RT_TICK_PER_SECOND);
lwp->rt_rusage.ru_utime.tv_sec += thread->user_time / RT_TICK_PER_SECOND;
lwp->rt_rusage.ru_utime.tv_usec += thread->user_time % RT_TICK_PER_SECOND * (1000000 / RT_TICK_PER_SECOND);
rt_list_remove(&thread->sibling);
LWP_UNLOCK(lwp);
lwp_futex_exit_robust_list(thread);
/**
* Note: the tid tree always hold a reference to thread, hence the tid must
* be release before cleanup of thread
*/
lwp_tid_put(thread->tid);
thread->tid = 0;
rt_thread_delete(thread);
rt_schedule();
while (1) ;
}
/**
* @brief Clear child thread ID notification for parent process
*
* @param[in,out] thread Thread whose child tid needs to be cleared
*
* @note This function performs the following operations:
* - Checks if clear_child_tid pointer is set
* - Writes 0 to user-space memory location if set
* - Wakes any futex waiters on that location
* - Clears the thread's clear_child_tid pointer
*/
rt_inline void _clear_child_tid(rt_thread_t thread)
{
if (thread->clear_child_tid)
{
int t = 0;
int *clear_child_tid = thread->clear_child_tid;
thread->clear_child_tid = RT_NULL;
lwp_put_to_user(clear_child_tid, &t, sizeof t);
sys_futex(clear_child_tid, FUTEX_WAKE, 1, RT_NULL, RT_NULL, 0);
}
}
/**
* @brief Terminates a lightweight process and cleans up its resources
*
* @param[in,out] lwp The lightweight process to terminate
* @param[in] status The exit status to set for the process
*
* @note This function handles both MMU and non-MMU architectures differently.
* For MMU architectures, it clears child TID, sets exit status, and terminates.
* For non-MMU, it terminates the main thread and all subthreads.
*/
void lwp_exit(rt_lwp_t lwp, lwp_status_t status)
{
rt_thread_t thread;
if (!lwp)
{
LOG_W("%s: lwp should not be null", __func__);
return ;
}
thread = rt_thread_self();
RT_ASSERT((struct rt_lwp *)thread->lwp == lwp);
LOG_D("process(lwp.pid=%d) exit", lwp->pid);
#ifdef ARCH_MM_MMU
_clear_child_tid(thread);
LWP_LOCK(lwp);
/**
* Brief: only one thread should calls exit_group(),
* but we can not ensured that during run-time
*/
lwp->lwp_status = status;
LWP_UNLOCK(lwp);
lwp_terminate(lwp);
#else
main_thread = rt_list_entry(lwp->t_grp.prev, struct rt_thread, sibling);
if (main_thread == tid)
{
rt_thread_t sub_thread;
rt_list_t *list;
lwp_terminate(lwp);
/* delete all subthread */
while ((list = tid->sibling.prev) != &lwp->t_grp)
{
sub_thread = rt_list_entry(list, struct rt_thread, sibling);
rt_list_remove(&sub_thread->sibling);
rt_thread_delete(sub_thread);
}
lwp->lwp_ret = value;
}
#endif /* ARCH_MM_MMU */
_thread_exit(lwp, thread);
}
/**
* @brief Handles thread exit for a lightweight process
*
* @param[in,out] thread The thread that is exiting
* @param[in] status The exit status to set for the thread
*
* @note For MMU architectures, this function checks if the exiting thread is the
* header thread (main thread). If so, it treats it as a process exit.
*/
void lwp_thread_exit(rt_thread_t thread, int status)
{
rt_thread_t header_thr;
struct rt_lwp *lwp;
LOG_D("%s", __func__);
RT_ASSERT(thread == rt_thread_self());
lwp = (struct rt_lwp *)thread->lwp;
RT_ASSERT(lwp != RT_NULL);
#ifdef ARCH_MM_MMU
_clear_child_tid(thread);
LWP_LOCK(lwp);
header_thr = rt_list_entry(lwp->t_grp.prev, struct rt_thread, sibling);
if (header_thr == thread && thread->sibling.prev == &lwp->t_grp)
{
/**
* if thread exit, treated as process exit normally.
* This is reasonable since trap event is exited through lwp_exit()
*/
lwp->lwp_status = LWP_CREATE_STAT_EXIT(status);
LWP_UNLOCK(lwp);
lwp_terminate(lwp);
}
else
{
LWP_UNLOCK(lwp);
}
#endif /* ARCH_MM_MMU */
_thread_exit(lwp, thread);
}
/**
* @brief Increments the reference count of a lightweight process
*
* @param[in,out] lwp The lightweight process whose reference count is to be incremented
*
* @return int The updated reference count after incrementing
*
* @note the reference is not for synchronization, but for the release of resource. the synchronization is done through lwp & pid lock.
*/
int lwp_ref_inc(struct rt_lwp *lwp)
{
int ref;
ref = rt_atomic_add(&lwp->ref, 1);
LOG_D("%s(%p(%s)): before %d", __func__, lwp, lwp->cmd, ref);
return ref;
}
/**
* @brief Decrements the reference count of a lightweight process (LWP)
*
* @param[in,out] lwp The lightweight process whose reference count to decrement
*
* @return int The reference count before decrementing
*
* @note This function atomically decrements the LWP's reference count.
* When the count reaches 1 (meaning this was the last reference):
* - For debug builds, sends a message to GDB server channel
* - For non-MMU architectures with shared memory support, frees shared memory
* - Calls lwp_free() to release all LWP resources
*/
int lwp_ref_dec(struct rt_lwp *lwp)
{
int ref;
ref = rt_atomic_add(&lwp->ref, -1);
LOG_D("%s(lwp=%p,lwp->cmd=%s): before ref=%d", __func__, lwp, lwp->cmd, ref);
if (ref == 1)
{
struct rt_channel_msg msg;
if (lwp->debug)
{
memset(&msg, 0, sizeof msg);
rt_raw_channel_send(gdb_server_channel(), &msg);
}
#ifndef ARCH_MM_MMU
#ifdef RT_LWP_USING_SHM
lwp_shm_lwp_free(lwp);
#endif /* RT_LWP_USING_SHM */
#endif /* not defined ARCH_MM_MMU */
lwp_free(lwp);
}
else
{
/* reference must be a positive integer */
RT_ASSERT(ref > 1);
}
return ref;
}
/**
* @brief Retrieves a lightweight process (LWP) by its PID while holding the lock
*
* @param[in] pid The process ID to look up
*
* @return struct rt_lwp* Pointer to the LWP structure if found, RT_NULL otherwise
*
* @note This function performs a raw lookup in the PID AVL tree while assuming
* the caller already holds the necessary locks. It's a lower-level version
* of lwp_from_pid() that doesn't handle locking internally.
*/
struct rt_lwp* lwp_from_pid_raw_locked(pid_t pid)
{
struct lwp_avl_struct *p;
struct rt_lwp *lwp = RT_NULL;
p = lwp_avl_find(pid, lwp_pid_root);
if (p)
{
lwp = (struct rt_lwp *)p->data;
}
return lwp;
}
/**
* @brief Retrieves a lightweight process (LWP) by PID with lock handling
*
* @param[in] pid The process ID to look up (0 means current process)
*
* @return struct rt_lwp* Pointer to the LWP structure if found, current LWP if pid=0
*
* @note This is a convenience wrapper that:
* - If pid is non-zero, calls lwp_from_pid_raw_locked()
* - If pid is zero, returns the current LWP via lwp_self()
*/
struct rt_lwp* lwp_from_pid_locked(pid_t pid)
{
struct rt_lwp* lwp;
lwp = pid ? lwp_from_pid_raw_locked(pid) : lwp_self();
return lwp;
}
/**
* @brief Converts a lightweight process (LWP) to its PID
*
* @param[in] lwp The LWP structure to convert
*
* @return pid_t The PID of the LWP, or 0 if lwp is NULL
*/
pid_t lwp_to_pid(struct rt_lwp* lwp)
{
if (!lwp)
{
return 0;
}
return lwp->pid;
}
/**
* @brief Convert process ID to process name
*
* @param[in] pid Process ID to look up
*
* @return char* Pointer to the process name (without path) if found, or RT_NULL if not found
*/
char* lwp_pid2name(int32_t pid)
{
struct rt_lwp *lwp;
char* process_name = RT_NULL;
lwp_pid_lock_take();
lwp = lwp_from_pid_locked(pid);
if (lwp)
{
process_name = strrchr(lwp->cmd, '/');
process_name = process_name? process_name + 1: lwp->cmd;
}
lwp_pid_lock_release();
return process_name;
}
/**
* @brief Convert process name to process ID
*
* @param[in] name Process name to look up (without path)
*
* @return pid_t Process ID if found, or 0 if not found
*
* @note The function only returns PIDs for processes whose main thread
* is not in CLOSED state.
*/
pid_t lwp_name2pid(const char *name)
{
int idx;
pid_t pid = 0;
rt_thread_t main_thread;
char* process_name = RT_NULL;
rt_sched_lock_level_t slvl;
lwp_pid_lock_take();
for (idx = 0; idx < RT_LWP_MAX_NR; idx++)
{
/* 0 is reserved */
struct rt_lwp *lwp = (struct rt_lwp *)lwp_pid_ary[idx].data;
if (lwp)
{
process_name = strrchr(lwp->exe_file, '/');
process_name = process_name? process_name + 1: lwp->cmd;
if (!rt_strncmp(name, process_name, RT_NAME_MAX))
{
main_thread = rt_list_entry(lwp->t_grp.prev, struct rt_thread, sibling);
rt_sched_lock(&slvl);
if (!(rt_sched_thread_get_stat(main_thread) == RT_THREAD_CLOSE))
{
pid = lwp->pid;
}
rt_sched_unlock(slvl);
}
}
}
lwp_pid_lock_release();
return pid;
}
/**
* @brief Get the process ID of the current lightweight process (LWP)
*
* @return pid_t Process ID of the current LWP
*/
int lwp_getpid(void)
{
rt_lwp_t lwp = lwp_self();
return lwp ? lwp->pid : 1;
/* return ((struct rt_lwp *)rt_thread_self()->lwp)->pid; */
}
/**
* @brief Update resource usage statistics from child to parent process
*
* @param[in] child Child process containing resource usage data
* @param[in] self_lwp Current lightweight process (parent)
* @param[in,out] uru Pointer to user-space rusage structure to update
*
* @note This function:
* - Copies system and user time from child process
* - Only updates if uru pointer is not NULL
* - Uses lwp_data_put to safely write to user-space memory
*/
rt_inline void _update_ru(struct rt_lwp *child, struct rt_lwp *self_lwp, struct rusage *uru)
{
struct rusage rt_rusage;
if (uru != RT_NULL)
{
rt_rusage.ru_stime.tv_sec = child->rt_rusage.ru_stime.tv_sec;
rt_rusage.ru_stime.tv_usec = child->rt_rusage.ru_stime.tv_usec;
rt_rusage.ru_utime.tv_sec = child->rt_rusage.ru_utime.tv_sec;
rt_rusage.ru_utime.tv_usec = child->rt_rusage.ru_utime.tv_usec;
lwp_data_put(self_lwp, uru, &rt_rusage, sizeof(*uru));
}
}
/**
* @brief Collects statistics and reaps a terminated child process
*
* @param[in] child The child process to collect statistics from
* @param[in] cur_thr The current thread context
* @param[in,out] self_lwp The parent process (current LWP)
* @param[out] ustatus Pointer to store child's exit status (optional)
* @param[in] options Wait options (e.g., WNOWAIT)
* @param[in,out] uru Pointer to resource usage structure to update (optional)
*
* @return rt_err_t Returns RT_EOK on success
*
* @note Updates resource usage statistics and optionally reaps the child process
*/
static rt_err_t _stats_and_reap_child(rt_lwp_t child, rt_thread_t cur_thr,
struct rt_lwp *self_lwp, int *ustatus,
int options, struct rusage *uru)
{
int lwp_stat = child->lwp_status;
/* report statistical data to process */
_update_ru(child, self_lwp, uru);
if (child->terminated && !(options & WNOWAIT))
{
/** Reap the child process if it's exited */
LOG_D("func %s: child detached", __func__);
lwp_pid_put(child);
lwp_children_unregister(self_lwp, child);
}
if (ustatus)
lwp_data_put(self_lwp, ustatus, &lwp_stat, sizeof(*ustatus));
return RT_EOK;
}
#define HAS_CHILD_BUT_NO_EVT (-1024)
/**
* @brief Queries process state change events from a child process
*
* @param[in] child The child process to query
* @param[in] cur_thr The current thread context
* @param[in] self_lwp The parent process (current LWP)
* @param[in] options Wait options (e.g., WSTOPPED)
* @param[out] status Pointer to store child's status (optional)
*
* @return sysret_t Returns child PID if event found, or HAS_CHILD_BUT_NO_EVT
*
* @note Checks for termination or stopped state changes in child process
*/
static sysret_t _query_event_from_lwp(rt_lwp_t child, rt_thread_t cur_thr, rt_lwp_t self_lwp,
int options, int *status)
{
sysret_t rc;
LWP_LOCK(child);
if (child->terminated)
{
rc = child->pid;
}
else if ((options & WSTOPPED) && child->jobctl_stopped && !child->wait_reap_stp)
{
child->wait_reap_stp = 1;
rc = child->pid;
}
else
{
rc = HAS_CHILD_BUT_NO_EVT;
}
LWP_UNLOCK(child);
LOG_D("%s(child_pid=%d ('%s'), stopped=%d) => %d", __func__, child->pid, child->cmd, child->jobctl_stopped, rc);
return rc;
}
/**
* @brief Verifies and reaps a child process if conditions are met
*
* @param[in] cur_thr Current thread context
* @param[in] self_lwp Parent process (current LWP)
* @param[in] wait_pid PID of child process to verify
* @param[in] options Wait options (e.g., WNOHANG)
* @param[out] ustatus Pointer to store child's exit status (optional)
* @param[in,out] uru Pointer to resource usage structure (optional)
*
* @return pid_t Returns child PID if valid and event found, error code otherwise
*
* @note Verifies child-parent relationship and checks for termination/stopped state
*/
static pid_t _verify_child_and_reap(rt_thread_t cur_thr, rt_lwp_t self_lwp,
pid_t wait_pid, int options, int *ustatus,
struct rusage *uru)
{
sysret_t rc;
struct rt_lwp *child;
/* check if pid is reference to a valid child */
lwp_pid_lock_take();
child = lwp_from_pid_locked(wait_pid);
if (!child)
rc = -EINVAL;
else if (child->parent != self_lwp)
rc = -ESRCH;
else
rc = wait_pid;
lwp_pid_lock_release();
if (rc > 0)
{
rc = _query_event_from_lwp(child, cur_thr, self_lwp, options, ustatus);
if (rc > 0)
{
_stats_and_reap_child(child, cur_thr, self_lwp, ustatus, options, uru);
}
}
return rc;
}
/**
* @brief Reaps any child process with given pair_pgid that has terminated or stopped
*
* @param[in] cur_thr Current thread context
* @param[in] self_lwp Parent process (current LWP)
* @param[in] pair_pgid Process group ID to match (0 for any)
* @param[in] options Wait options (e.g., WNOHANG)
* @param[out] ustatus Pointer to store child's exit status (optional)
* @param[in,out] uru Pointer to resource usage structure (optional)
*
* @return pid_t Returns child PID if found and event occurred, error code otherwise
*
* @note Iterates through child processes to find one that matches given pair_pgid
*/
static pid_t _reap_any_child_pid(rt_thread_t cur_thr, rt_lwp_t self_lwp, pid_t pair_pgid,
int options, int *ustatus, struct rusage *uru)
{
sysret_t rc = -ECHILD;
struct rt_lwp *child;
LWP_LOCK(self_lwp);
child = self_lwp->first_child;
/* find a exited child if any */
while (child)
{
if (pair_pgid && child->pgid != pair_pgid)
continue;
rc = _query_event_from_lwp(child, cur_thr, self_lwp, options, ustatus);
if (rc > 0)
break;
child = child->sibling;
}
LWP_UNLOCK(self_lwp);
if (rc > 0)
{
_stats_and_reap_child(child, cur_thr, self_lwp, ustatus, options, uru);
}
return rc;
}
/**
* @brief Wakes up processes waiting for a child process status change
*
* @param[in] parent Parent process to notify
* @param[in] self_lwp Child process that triggered the wakeup
*
* @return rt_err_t Returns RT_EOK on success
*
* @note Uses wait queue to notify parent process about child status changes
*/
rt_err_t lwp_waitpid_kick(rt_lwp_t parent, rt_lwp_t self_lwp)
{
/* waker provide the message mainly through its lwp_status */
rt_wqueue_wakeup(&parent->waitpid_waiters, self_lwp);
return RT_EOK;
}
/**
* @brief Waitpid handle structure for process status change notifications
*
* @note This structure is used to manage wait queue entries for processes waiting
* for child process status changes.
*/
struct waitpid_handle {
struct rt_wqueue_node wq_node; /**< Wait queue node for process status change notifications */
int options; /**< Wait options (e.g., WNOHANG, WUNTRACED) */
rt_lwp_t waker_lwp; /**< LWP that triggered the wakeup */
};
/**
* @brief Filter function for wait queue to determine if a process status change event should be accepted
*
* @param[in] wait_node Wait queue node containing filter criteria
* @param[in] key Pointer to the lightweight process (waker_lwp) triggering the event
*
* @return int 0 if event should be accepted (matches criteria), 1 if event should be discarded
*
* @note The function handles three cases for process matching:
* - Positive destiny: Exact PID match
* - destiny == -1: Any child process of waiter
* - destiny == 0/-pgid: Process group matching
*/
static int _waitq_filter(struct rt_wqueue_node *wait_node, void *key)
{
int can_accept_evt = 0;
rt_thread_t waiter = wait_node->polling_thread;
pid_t destiny = (pid_t)wait_node->key;
rt_lwp_t waker_lwp = key;
struct waitpid_handle *handle;
rt_ubase_t options;
handle = rt_container_of(wait_node, struct waitpid_handle, wq_node);
RT_ASSERT(waiter != RT_NULL);
options = handle->options;
/* filter out if waker is not the one */
if (destiny > 0)
{
/**
* in waitpid immediately return routine, we already do the check
* that pid is one of the child process of waiting thread
*/
can_accept_evt = waker_lwp->pid == destiny;
}
else if (destiny == -1)
{
can_accept_evt = waker_lwp->parent == waiter->lwp;
}
else
{
/* destiny == 0 || destiny == -pgid */
pid_t waiter_pgid;
if (destiny == 0)
{
waiter_pgid = lwp_pgid_get_byprocess(waiter->lwp);
}
else
{
waiter_pgid = -destiny;
}
can_accept_evt = waiter_pgid == lwp_pgid_get_byprocess(waker_lwp);
}
/* filter out if event is not desired */
if (can_accept_evt)
{
if ((options & WEXITED) && waker_lwp->terminated)
can_accept_evt = 1;
else if ((options & WSTOPPED) && WIFSTOPPED(waker_lwp->lwp_status))
can_accept_evt = 1;
else if ((options & WCONTINUED) && WIFCONTINUED(waker_lwp->lwp_status))
can_accept_evt = 1;
else
can_accept_evt = 0;
}
/* setup message for waiter if accepted */
if (can_accept_evt)
handle->waker_lwp = waker_lwp;
/* 0 if event is accepted, otherwise discard */
return !can_accept_evt;
}
/**
* @brief Wait for a child process status change event
*
* @param[in] cur_thr Current thread context that will be suspended
* @param[in] self_lwp Lightweight process (parent) waiting for the event
* @param[in,out] handle Waitpid handle containing filter criteria and wait queue node
* @param[in] destiny Process ID or process group to wait for (-1 for any child, -pgid for process group)
*
* @return rt_err_t RT_EOK on success, negative error code on failure
*
* @note This function suspends the current thread to wait for a child process status change
* event that matches the specified criteria (process ID or process group).
*/
static rt_err_t _wait_for_event(rt_thread_t cur_thr, rt_lwp_t self_lwp,
struct waitpid_handle *handle, pid_t destiny)
{
rt_err_t ret;
/* current context checking */
RT_DEBUG_SCHEDULER_AVAILABLE(RT_TRUE);
handle->wq_node.polling_thread = cur_thr;
handle->wq_node.key = destiny;
handle->wq_node.wakeup = _waitq_filter;
handle->wq_node.wqueue = &self_lwp->waitpid_waiters;
rt_list_init(&handle->wq_node.list);
cur_thr->error = RT_EOK;
LOG_D("%s(self_lwp=%d) wait for event", __func__, self_lwp->pid);
rt_enter_critical();
ret = rt_thread_suspend_with_flag(cur_thr, RT_INTERRUPTIBLE);
if (ret == RT_EOK)
{
rt_wqueue_add(handle->wq_node.wqueue, &handle->wq_node);
rt_exit_critical();
rt_schedule();
ret = cur_thr->error;
/**
* cur_thr error is a positive value, but some legacy implementation
* use a negative one. So we check to avoid errors
*/
ret = ret > 0 ? -ret : ret;
/**
* we dont rely on this actually, but we cleanup it since wakeup API
* set this up durint operation, and this will cause some messy condition
*/
handle->wq_node.wqueue->flag = RT_WQ_FLAG_CLEAN;
rt_wqueue_remove(&handle->wq_node);
}
else
{
/* failed to suspend, return immediately with failure */
rt_exit_critical();
}
return ret;
}
/**
* @brief Wait for and reap a child process status change
*
* @param[in] cur_thr Current thread context
* @param[in] self_lwp Lightweight process (parent) waiting for the child
* @param[in] pid Process ID to wait for (-1 for any child, -pgid for process group)
* @param[in] options Wait options (WNOHANG, WUNTRACED, etc.)
* @param[out] ustatus Pointer to store child exit status
* @param[in,out] uru Pointer to resource usage structure to update
*
* @return sysret_t PID of the child process that changed status, or error code
*
* @note The function:
* - Uses _wait_for_event to wait for status changes
* - Calls _stats_and_reap_child if a matching child is found
*/
static sysret_t _wait_and_reap(rt_thread_t cur_thr, rt_lwp_t self_lwp, const pid_t pid,
int options, int *ustatus, struct rusage *uru)
{
sysret_t rc;
struct waitpid_handle handle;
rt_lwp_t waker;
/* wait for SIGCHLD or other async events */
handle.options = options;
handle.waker_lwp = 0;
rc = _wait_for_event(cur_thr, self_lwp, &handle, pid);
waker = handle.waker_lwp;
if (waker != RT_NULL)
{
rc = waker->pid;
/* check out if any process exited */
LOG_D("%s: woken up by lwp=%d", __func__, waker->pid);
_stats_and_reap_child(waker, cur_thr, self_lwp, ustatus, options, uru);
}
/**
* else if (rc != RT_EOK)
* unable to do a suspend, or wakeup unexpectedly
* -> then returned a failure
*/
return rc;
}
/**
* @brief Wait for process termination and return status
*
* @param[in] pid Process ID to wait for:
* >0 - specific child process
* -1 - any child process
* -pgid - any child in process group
* 0 - any child in caller's process group
* @param[out] status Pointer to store child exit status (optional)
* @param[in] options Wait options (WNOHANG, WUNTRACED, etc.)
* @param[in,out] ru Pointer to resource usage structure (optional)
*
* @return pid_t PID of the child that changed state, or:
* -1 on error
* 0 if WNOHANG and no child status available
*
* @note The function handles three cases:
* - Specific PID wait (pid > 0)
* - Any child wait (pid == -1)
* - Process group wait (pid == 0 or pid < -1)
*/
pid_t lwp_waitpid(const pid_t pid, int *status, int options, struct rusage *ru)
{
pid_t rc = -1;
struct rt_thread *cur_thr;
struct rt_lwp *self_lwp;
cur_thr = rt_thread_self();
self_lwp = lwp_self();
if (!cur_thr || !self_lwp)
{
rc = -EINVAL;
}
else
{
/* check if able to reap desired child immediately */
if (pid > 0)
{
/* if pid is child then try to reap it */
rc = _verify_child_and_reap(cur_thr, self_lwp, pid, options, status, ru);
}
else if (pid == -1)
{
/* any terminated child */
rc = _reap_any_child_pid(cur_thr, self_lwp, 0, options, status, ru);
}
else
{
/**
* (pid < -1 || pid == 0)
* any terminated child with matched pgid
*/
pid_t pair_pgid;
if (pid == 0)
{
pair_pgid = lwp_pgid_get_byprocess(self_lwp);
}
else
{
pair_pgid = -pid;
}
rc = _reap_any_child_pid(cur_thr, self_lwp, pair_pgid, options, status, ru);
}
if (rc == HAS_CHILD_BUT_NO_EVT)
{
if (!(options & WNOHANG))
{
/* otherwise, arrange a suspend and wait for async event */
options |= WEXITED;
rc = _wait_and_reap(cur_thr, self_lwp, pid, options, status, ru);
}
else
{
/**
* POSIX.1: If waitpid() was invoked with WNOHANG set in options,
* it has at least one child process specified by pid for which
* status is not available, and status is not available for any
* process specified by pid, 0 is returned
*/
rc = 0;
}
}
else
{
RT_ASSERT(rc != 0);
}
}
LOG_D("waitpid() => %d, *status=0x%x", rc, status ? *status:0);
return rc;
}
/**
* @brief Waits for a child process to terminate
*
* @param[in] pid The process ID to wait for
* @param[out] status Pointer to store child exit status (optional)
* @param[in] options Wait options (e.g., WNOHANG, WUNTRACED)
*
* @return pid_t The process ID of the child whose state changed,
* -1 on error, or 0 if WNOHANG was specified and no child was available
*
* @note This is a wrapper function that calls lwp_waitpid with NULL for the resource usage parameter
*/
pid_t waitpid(pid_t pid, int *status, int options)
{
return lwp_waitpid(pid, status, options, RT_NULL);
}
#ifdef RT_USING_FINSH
/**
* @brief Prints a line of dashes for visual separation
*
* @param[in] len Number of dashes to print
*/
static void object_split(int len)
{
while (len--)
{
rt_kprintf("-");
}
}
/**
* @brief Prints detailed information about a thread
*
* @param[in] thread Pointer to the thread structure to print information about
* @param[in] maxlen Maximum length for thread name display
*
* @note This function prints:
* - CPU core (SMP only) and priority
* - Thread state (ready, suspended, init, close, running)
* - Stack information (usage percentage, size, etc.)
* - Remaining tick count and error code
* - Thread name
*/
static void print_thread_info(struct rt_thread* thread, int maxlen)
{
rt_uint8_t *ptr;
rt_uint8_t stat;
#ifdef RT_USING_SMP
if (RT_SCHED_CTX(thread).oncpu != RT_CPU_DETACHED)
rt_kprintf("%3d %3d ", RT_SCHED_CTX(thread).oncpu, RT_SCHED_PRIV(thread).current_priority);
else
rt_kprintf("N/A %3d ", RT_SCHED_PRIV(thread).current_priority);
#else
rt_kprintf("%3d ", RT_SCHED_PRIV(thread).current_priority);
#endif /*RT_USING_SMP*/
stat = (RT_SCHED_CTX(thread).stat & RT_THREAD_STAT_MASK);
if (stat == RT_THREAD_READY) rt_kprintf(" ready ");
else if ((stat & RT_THREAD_SUSPEND_MASK) == RT_THREAD_SUSPEND_MASK) rt_kprintf(" suspend");
else if (stat == RT_THREAD_INIT) rt_kprintf(" init ");
else if (stat == RT_THREAD_CLOSE) rt_kprintf(" close ");
else if (stat == RT_THREAD_RUNNING) rt_kprintf(" running");
#if defined(ARCH_CPU_STACK_GROWS_UPWARD)
ptr = (rt_uint8_t *)thread->stack_addr + thread->stack_size;
while (*ptr == '#')ptr--;
rt_kprintf(" 0x%08x 0x%08x %02d%% 0x%08x %03d\n",
((rt_uint32_t)thread->sp - (rt_uint32_t)thread->stack_addr),
thread->stack_size,
((rt_uint32_t)ptr - (rt_uint32_t)thread->stack_addr) * 100 / thread->stack_size,
thread->remaining_tick,
thread->error);
#else
ptr = (rt_uint8_t *)thread->stack_addr;
while (*ptr == '#')ptr++;
rt_kprintf(" 0x%08x 0x%08x %02d%% 0x%08x %03d",
(thread->stack_size + (rt_uint32_t)(rt_size_t)thread->stack_addr - (rt_uint32_t)(rt_size_t)thread->sp),
thread->stack_size,
(thread->stack_size + (rt_uint32_t)(rt_size_t)thread->stack_addr - (rt_uint32_t)(rt_size_t)ptr) * 100
/ thread->stack_size,
RT_SCHED_PRIV(thread).remaining_tick,
thread->error);
#endif
rt_kprintf(" %-.*s\n",rt_strlen(thread->parent.name), thread->parent.name);
}
/**
* @brief Lists all processes and threads in the system
*
* @return long Returns 0 on success
*
* @note This function:
* - Prints a header with process/thread information columns
* - Lists all kernel threads (without LWP association)
* - Lists all user processes (LWPs) with their threads
* - For each thread, displays:
* - PID/TID (process/thread IDs)
* - Priority, status, stack information
* - Remaining tick count and error code
* - Thread name/command
*/
long list_process(void)
{
int index;
int maxlen;
rt_ubase_t level;
struct rt_thread *thread;
struct rt_list_node *node, *list;
const char *item_title = "thread";
int count = 0;
struct rt_thread **threads;
maxlen = RT_NAME_MAX;
#ifdef RT_USING_SMP
rt_kprintf("%-*.s %-*.s %-*.s cpu pri status sp stack size max used left tick error %-*.s\n", 4, "PID", 4, "TID", maxlen, item_title, maxlen, "cmd");
object_split(4);rt_kprintf(" ");object_split(4);rt_kprintf(" ");object_split(maxlen);rt_kprintf(" ");
rt_kprintf( "--- --- ------- ---------- ---------- -------- ---------- -----");rt_kprintf(" ");object_split(maxlen);rt_kprintf("\n");
#else
rt_kprintf("%-*.s %-*.s %-*.s pri status sp stack size max used left tick error\n", 4, "PID", 4, "TID", maxlen, item_title, maxlen, "cmd");
object_split(4);rt_kprintf(" ");object_split(4);rt_kprintf(" ");object_split(maxlen);rt_kprintf(" ");
rt_kprintf( "--- ------- ---------- ---------- -------- ---------- -----");rt_kprintf(" ");object_split(maxlen);rt_kprintf("\n");
#endif /*RT_USING_SMP*/
count = rt_object_get_length(RT_Object_Class_Thread);
if (count > 0)
{
/* get thread pointers */
threads = (struct rt_thread **)rt_calloc(count, sizeof(struct rt_thread *));
if (threads)
{
index = rt_object_get_pointers(RT_Object_Class_Thread, (rt_object_t *)threads, count);
if (index > 0)
{
for (index = 0; index <count; index++)
{
struct rt_thread th;
thread = threads[index];
level = rt_spin_lock_irqsave(&thread->spinlock);
if ((rt_object_get_type(&thread->parent) & ~RT_Object_Class_Static) != RT_Object_Class_Thread)
{
rt_spin_unlock_irqrestore(&thread->spinlock, level);
continue;
}
rt_memcpy(&th, thread, sizeof(struct rt_thread));
rt_spin_unlock_irqrestore(&thread->spinlock, level);
if (th.lwp == RT_NULL)
{
rt_kprintf(" %-*.*s ", maxlen, RT_NAME_MAX, "kernel");
print_thread_info(&th, maxlen);
}
}
}
rt_free(threads);
}
}
for (index = 0; index < RT_LWP_MAX_NR; index++)
{
struct rt_lwp *lwp = (struct rt_lwp *)lwp_pid_ary[index].data;
if (lwp)
{
list = &lwp->t_grp;
for (node = list->next; node != list; node = node->next)
{
thread = rt_list_entry(node, struct rt_thread, sibling);
rt_kprintf("%4d %4d %-*.*s ", lwp_to_pid(lwp), thread->tid, maxlen, RT_NAME_MAX, lwp->cmd);
print_thread_info(thread, maxlen);
}
}
}
return 0;
}
MSH_CMD_EXPORT(list_process, list process);
/**
* @brief Command handler for killing processes
*
* @param[in] argc Argument count
* @param[in] argv Argument vector (contains PID and optional signal)
*
* @note Usage:
* - kill <pid>
* - kill <pid> -s <signal>
* Default signal is SIGKILL (9)
*/
static void cmd_kill(int argc, char** argv)
{
int pid;
int sig = SIGKILL;
if (argc < 2)
{
rt_kprintf("kill pid or kill pid -s signal\n");
return;
}
pid = atoi(argv[1]);
if (argc >= 4)
{
if (argv[2][0] == '-' && argv[2][1] == 's')
{
sig = atoi(argv[3]);
}
}
lwp_pid_lock_take();
lwp_signal_kill(lwp_from_pid_raw_locked(pid), sig, SI_USER, 0);
lwp_pid_lock_release();
}
MSH_CMD_EXPORT_ALIAS(cmd_kill, kill, send a signal to a process);
/**
* @brief Kills all processes matching the given name
*
* @param[in] argc Argument count (must be >= 2)
* @param[in] argv Argument vector containing process name to kill
*
* @note Sends SIGKILL signal to all processes with the specified name.
* Requires at least 2 arguments (command name + process name)
*/
static void cmd_killall(int argc, char** argv)
{
int pid;
if (argc < 2)
{
rt_kprintf("killall processes_name\n");
return;
}
while((pid = lwp_name2pid(argv[1])) > 0)
{
lwp_pid_lock_take();
lwp_signal_kill(lwp_from_pid_raw_locked(pid), SIGKILL, SI_USER, 0);
lwp_pid_lock_release();
rt_thread_mdelay(100);
}
}
MSH_CMD_EXPORT_ALIAS(cmd_killall, killall, kill processes by name);
#endif
/**
* @brief Checks if the current thread has received an exit request
*
* @return int Returns:
* - 0 if no exit request or not an LWP thread
* - 1 if exit request was triggered and set to IN_PROCESS
*
* @note Verifies if the current lightweight process thread has been requested to exit
* by checking the exit_request atomic flag.
*/
int lwp_check_exit_request(void)
{
rt_thread_t thread = rt_thread_self();
rt_size_t expected = LWP_EXIT_REQUEST_TRIGGERED;
if (!thread->lwp)
{
return 0;
}
return atomic_compare_exchange_strong(&thread->exit_request, &expected,
LWP_EXIT_REQUEST_IN_PROCESS);
}
static void _wait_sibling_exit(rt_lwp_t lwp, rt_thread_t curr_thread);
static void _resr_cleanup(struct rt_lwp *lwp);
/**
* @brief Terminates a lightweight process (LWP)
*
* @param[in,out] lwp Pointer to the lightweight process structure to terminate
*
* @note Safely terminates an LWP by marking it as terminated, waiting for sibling threads,
* and cleaning up resources.
*/
void lwp_terminate(struct rt_lwp *lwp)
{
if (!lwp)
{
/* kernel thread not support */
return;
}
LOG_D("%s(lwp=%p \"%s\")", __func__, lwp, lwp->cmd);
LWP_LOCK(lwp);
if (!lwp->terminated)
{
/* stop the receiving of signals */
lwp->terminated = RT_TRUE;
LWP_UNLOCK(lwp);
_wait_sibling_exit(lwp, rt_thread_self());
_resr_cleanup(lwp);
}
else
{
LWP_UNLOCK(lwp);
}
}
/**
* @brief Waits for sibling threads to exit during process termination
*
* @param[in] lwp Pointer to the lightweight process structure
* @param[in] curr_thread Current thread context making the termination request
*
* @note Details for this function:
* - Broadcast Exit Request: Broadcasts exit requests to all sibling threads.
* - Wake Suspended Threads: Wakes up any suspended threads by setting their error status to RT_EINTR.
* - Wait for Termination: it enters a loop waiting for all sibling threads to terminate.
* - Cleanup Terminated Threads: Once threads are in the INIT state, it removes them from the sibling list
* and deletes their thread control blocks.
*/
static void _wait_sibling_exit(rt_lwp_t lwp, rt_thread_t curr_thread)
{
rt_sched_lock_level_t slvl;
rt_list_t *list;
rt_thread_t thread;
rt_size_t expected = LWP_EXIT_REQUEST_NONE;
/* broadcast exit request for sibling threads */
LWP_LOCK(lwp);
for (list = lwp->t_grp.next; list != &lwp->t_grp; list = list->next)
{
thread = rt_list_entry(list, struct rt_thread, sibling);
atomic_compare_exchange_strong(&thread->exit_request, &expected,
LWP_EXIT_REQUEST_TRIGGERED);
rt_sched_lock(&slvl);
/* dont release, otherwise thread may have been freed */
if (rt_sched_thread_is_suspended(thread))
{
thread->error = RT_EINTR;
rt_sched_unlock(slvl);
rt_thread_wakeup(thread);
}
else
{
rt_sched_unlock(slvl);
}
}
LWP_UNLOCK(lwp);
while (1)
{
int subthread_is_terminated;
LOG_D("%s: wait for subthread exiting", __func__);
/**
* Brief: wait for all *running* sibling threads to exit
*
* Note: Critical Section
* - sibling list of lwp (RW. It will clear all siblings finally)
*/
LWP_LOCK(lwp);
subthread_is_terminated = (int)(curr_thread->sibling.prev == &lwp->t_grp);
if (!subthread_is_terminated)
{
rt_sched_lock_level_t slvl;
rt_thread_t sub_thread;
rt_list_t *list;
int all_subthread_in_init = 1;
/* check all subthread is in init state */
for (list = curr_thread->sibling.prev; list != &lwp->t_grp; list = list->prev)
{
rt_sched_lock(&slvl);
sub_thread = rt_list_entry(list, struct rt_thread, sibling);
if (rt_sched_thread_get_stat(sub_thread) != RT_THREAD_INIT)
{
rt_sched_unlock(slvl);
all_subthread_in_init = 0;
break;
}
else
{
rt_sched_unlock(slvl);
}
}
if (all_subthread_in_init)
{
/* delete all subthread */
while ((list = curr_thread->sibling.prev) != &lwp->t_grp)
{
sub_thread = rt_list_entry(list, struct rt_thread, sibling);
rt_list_remove(&sub_thread->sibling);
/**
* Note: Critical Section
* - thread control block (RW. Since it will free the thread
* control block, it must ensure no one else can access
* thread any more)
*/
lwp_tid_put(sub_thread->tid);
sub_thread->tid = 0;
rt_thread_delete(sub_thread);
}
subthread_is_terminated = 1;
}
}
LWP_UNLOCK(lwp);
if (subthread_is_terminated)
{
break;
}
rt_thread_mdelay(10);
}
}
/**
* @brief Notifies parent process about child process termination
*
* @param[in,out] lwp The child lightweight process structure
*
* @note This function sends SIGCHLD signal to parent process with termination details.
* It handles both signaled (killed/dumped) and normal exit cases.
*/
static void _notify_parent(rt_lwp_t lwp)
{
int si_code;
int signo_or_exitcode;
lwp_siginfo_ext_t ext;
lwp_status_t lwp_status = lwp->lwp_status;
rt_lwp_t parent = lwp->parent;
if (WIFSIGNALED(lwp_status))
{
si_code = (lwp_status & LWP_COREDUMP_FLAG) ? CLD_DUMPED : CLD_KILLED;
signo_or_exitcode = WTERMSIG(lwp_status);
}
else
{
si_code = CLD_EXITED;
signo_or_exitcode = WEXITSTATUS(lwp->lwp_status);
}
lwp_waitpid_kick(parent, lwp);
ext = rt_malloc(sizeof(struct lwp_siginfo));
if (ext)
{
rt_thread_t cur_thr = rt_thread_self();
ext->sigchld.status = signo_or_exitcode;
ext->sigchld.stime = cur_thr->system_time;
ext->sigchld.utime = cur_thr->user_time;
}
lwp_signal_kill(parent, SIGCHLD, si_code, ext);
}
/**
* @brief Clean up resources when a lightweight process (LWP) terminates
*
* @param[in,out] lwp The lightweight process structure to clean up
*
* @note This function handles the cleanup of various resources associated with an LWP
* when it terminates, including:
* - Job control cleanup
* - Signal detachment
* - Child process handling
* - Parent notification
* - File descriptor cleanup
* - PID resource release
*/
static void _resr_cleanup(struct rt_lwp *lwp)
{
int need_cleanup_pid = RT_FALSE;
lwp_jobctrl_on_exit(lwp);
LWP_LOCK(lwp);
lwp_signal_detach(&lwp->signal);
/**
* @brief Detach children from lwp
*
* @note Critical Section
* - the lwp (RW. Release lwp)
* - the pid resource manager (RW. Release the pid)
*/
while (lwp->first_child)
{
struct rt_lwp *child;
child = lwp->first_child;
lwp->first_child = child->sibling;
/** @note safe since the slist node is release */
LWP_UNLOCK(lwp);
LWP_LOCK(child);
if (child->terminated)
{
lwp_pid_put(child);
}
else
{
child->sibling = RT_NULL;
/* info: this may cause an orphan lwp */
child->parent = RT_NULL;
}
LWP_UNLOCK(child);
lwp_ref_dec(child);
lwp_ref_dec(lwp);
LWP_LOCK(lwp);
}
LWP_UNLOCK(lwp);
/**
* @brief Wakeup parent if it's waiting for this lwp, otherwise a signal
* will be sent to parent
*
* @note Critical Section
* - the parent lwp (RW.)
*/
LWP_LOCK(lwp);
if (lwp->parent &&
!lwp_sigismember(&lwp->parent->signal.sig_action_nocldwait, SIGCHLD))
{
/* if successfully race to setup lwp->terminated before parent detach */
LWP_UNLOCK(lwp);
/**
* Note: children cannot detach itself and must wait for parent to take
* care of it
*/
_notify_parent(lwp);
}
else
{
LWP_UNLOCK(lwp);
/**
* if process is orphan, it doesn't have parent to do the recycling.
* Otherwise, its parent had setup a flag to mask out recycling event
*/
need_cleanup_pid = RT_TRUE;
}
LWP_LOCK(lwp);
if (lwp->fdt.fds != RT_NULL)
{
struct dfs_file **fds;
/* auto clean fds */
__exit_files(lwp);
fds = lwp->fdt.fds;
lwp->fdt.fds = RT_NULL;
LWP_UNLOCK(lwp);
rt_free(fds);
}
else
{
LWP_UNLOCK(lwp);
}
if (need_cleanup_pid)
{
lwp_pid_put(lwp);
}
}
/**
* @brief Set CPU affinity for a thread
*
* @param[in] tid The thread ID to set affinity for
* @param[in] cpu The target CPU core number
*
* @return 0 on success, -1 on failure (invalid thread ID)
*
* @note This function binds a thread to a specific CPU core in SMP systems.
* It handles thread reference counting and returns operation status.
*/
static int _lwp_setaffinity(int tid, int cpu)
{
rt_thread_t thread;
int ret = -1;
thread = lwp_tid_get_thread_and_inc_ref(tid);
if (thread)
{
#ifdef RT_USING_SMP
rt_thread_control(thread, RT_THREAD_CTRL_BIND_CPU, (void *)(rt_ubase_t)cpu);
#endif
ret = 0;
}
lwp_tid_dec_ref(thread);
return ret;
}
/**
* @brief Sets CPU affinity for a thread
*
* @param[in] tid The thread ID to set affinity for
* @param[in] cpu The target CPU core number (0 to RT_CPUS_NR-1)
*
* @return int 0 on success, -1 on failure
*
* @note wrapper function for _lwp_setaffinity
*/
int lwp_setaffinity(int tid, int cpu)
{
int ret;
#ifdef RT_USING_SMP
if (cpu < 0 || cpu > RT_CPUS_NR)
{
cpu = RT_CPUS_NR;
}
#endif
ret = _lwp_setaffinity(tid, cpu);
return ret;
}
#ifdef RT_USING_SMP
/**
* @brief Command handler for CPU binding operation
*
* @param[in] argc Number of command arguments
* @param[in] argv Array of command argument strings
*
* @note Requires exactly 2 arguments: pid (process ID) and cpu (CPU core number)
*/
static void cmd_cpu_bind(int argc, char** argv)
{
int pid;
int cpu;
if (argc < 3)
{
rt_kprintf("Useage: cpu_bind pid cpu\n");
return;
}
pid = atoi(argv[1]);
cpu = atoi(argv[2]);
lwp_setaffinity((pid_t)pid, cpu);
}
MSH_CMD_EXPORT_ALIAS(cmd_cpu_bind, cpu_bind, set a process bind to a cpu);
#endif
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