Creating and deleting threads dynamically in eCos

来源：

http://simonccheng.spaces.live.com/

下面的例子說明如何在eCos裡面動態產生thread.

Echo_Child 是要新產生的child thread,

紅色字為所需要用的的kernel API

Echo_Child_Cleaner可重要了,用來清除已經完成離開的child thread,

其中特別用來清除kernel scheduler的instance handle & structure, and stack

另外釋放child_info 的instance struct讓給下一個使用

 

程式裡用的是TCP port 6000的

能夠連接的connection 為 SIZE_OF_CHILD_INFO  

 

#include <cyg/kernel/kapi.h>

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <network.h>

#define SIZE_OF_CHILD_INFO  10
#define MAX_SIZE_OF_STACK  4096
#define PRIORITY_SERVER   4
#define SERVER_PORT    6000

typedef struct _tagCHILD_INFO_ {
 cyg_tick_count_t  delay;
 cyg_handle_t   handle;
 cyg_thread    thread;
 int     fd;
 char     stack[MAX_SIZE_OF_STACK];
} CHILD_INFO, *PCHILD_INFO;

 

char server_stack[MAX_SIZE_OF_STACK];
char cleaner_stack[MAX_SIZE_OF_STACK];

cyg_handle_t EchoServerHandle, EchoChildCleanerHandle;
cyg_thread_entry_t Echo_Server, Echo_Child_Cleaner, Echo_Child;
cyg_thread Echo_Server_Thread, Echo_Child_Cleaner_Thread;

cyg_handle_t  cleaner_mbox_handle;
cyg_mbox   cleaner_mbox;

CHILD_INFO  child_info[SIZE_OF_CHILD_INFO];

void Echo_Child_Cleaner(cyg_addrword_t data);
cyg_bool_t Tell_Cleaner(PCHILD_INFO pInfo);

extern void cyg_test_exit(void);

void pexit(char *s)
{
    perror(s);
    cyg_test_exit();
}

void cyg_user_start(void)
{
     cyg_thread_create(PRIORITY_SERVER, Echo_Child_Cleaner, (cyg_addrword_t) 0,
         "Echo Child Cleaner", (void *) cleaner_stack, MAX_SIZE_OF_STACK,
          &EchoChildCleanerHandle, &Echo_Child_Cleaner_Thread);
     cyg_thread_resume(EchoChildCleanerHandle);  
 
     cyg_thread_create(PRIORITY_SERVER, Echo_Server, (cyg_addrword_t) 0,
         "Echo Server", (void *) server_stack, MAX_SIZE_OF_STACK * 16,
         &EchoServerHandle, &Echo_Server_Thread);
     cyg_thread_resume(EchoServerHandle); 
 
     cyg_scheduler_start();
}

void Echo_Server(cyg_addrword_t data)
{
    int s, client, res;
    socklen_t client_len;
    struct sockaddr_in client_addr, local;
    int one = 1;
    PCHILD_INFO pChildInfo;
    cyg_handle_t system_clockH;
    cyg_resolution_t rtc_res;
    int index;
     

    init_all_network_interfaces();

    if (!eth0_up) {
        pexit("eth0 not up");
    }
   
    for (index=0;index<SIZE_OF_CHILD_INFO;index++) {
        memset(&child_info[index], 0, sizeof(CHILD_INFO));
    }
   
    system_clockH = cyg_real_time_clock();
    rtc_res = cyg_clock_get_resolution(system_clockH); 
    
    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s < 0) {
        pexit("stream socket");
    }
   
    if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
        pexit("setsockopt SO_REUSEADDR");
    }
    if (setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one))) {
        pexit("setsockopt SO_REUSEPORT");
    }
   
    memset(&local, 0, sizeof(local));
    local.sin_family = AF_INET;
    local.sin_len = sizeof(local);
    local.sin_port = htons(SERVER_PORT);
    local.sin_addr.s_addr = INADDR_ANY;
    if((res = bind(s, (struct sockaddr *) &local, sizeof(local))) < 0) {
        pexit("bind error");
    }
    listen(s, SOMAXCONN);
    while (true) {

        client_len = sizeof(client_addr);
        if ((client = accept(s, (struct sockaddr *)&client_addr, &client_len)) < 0) {
            pexit("accept");
        }
        for (index=0,pChildInfo=NULL;index<SIZE_OF_CHILD_INFO;index++) {
         if (child_info[index].delay == 0) {
             pChildInfo = &child_info[index];
             pChildInfo->delay = (long long)((1000000000.0*rtc_res.divisor)
                 *((double)1)/((double)rtc_res.dividend));  //1 sec  
             break;
         }
    }
     
       if (pChildInfo) {
           pChildInfo->fd = client;
   
           cyg_thread_create(PRIORITY_SERVER, Echo_Child, (cyg_addrword_t) pChildInfo,
               "Echo Child", (void *) pChildInfo->stack, MAX_SIZE_OF_STACK,
               &pChildInfo->handle, &pChildInfo->thread);
           cyg_thread_resume(pChildInfo->handle);    
   
        } else {
            perror("no instance available");
            close(client);
        }
  
    }
    close(s); // never happen here...
    cyg_thread_exit();
}

 

 

void Echo_Child(cyg_addrword_t data)
{
 PCHILD_INFO pChildInfo = (PCHILD_INFO)data;
 char buf[1024];
 int len;
    fd_set in_fds;
    struct timeval tv; 
 
 do {
  len=0;
     tv.tv_sec = 5;  // 5 sec
     tv.tv_usec = 0;
     FD_ZERO(&in_fds);
     FD_SET(pChildInfo->fd, &in_fds);
     len = select(pChildInfo->fd+1, &in_fds, 0, 0, &tv);
     if (len > 0) {
      len = read(pChildInfo->fd, buf, sizeof(buf));
      write(pChildInfo->fd, buf, len);
     } else if (len < 0) {
      pexit("select error");
      len = 0;
     }
 } while (len);    

 if (pChildInfo->fd)
  close(pChildInfo->fd); 
 Tell_Cleaner(pChildInfo);
 cyg_thread_exit();
} 

 

void Echo_Child_Cleaner(cyg_addrword_t data)
{
 PCHILD_INFO pChildInfo;
 cyg_mbox_create(&cleaner_mbox_handle, &cleaner_mbox);
 
 while (cleaner_mbox_handle) {
  pChildInfo = (PCHILD_INFO)cyg_mbox_get(cleaner_mbox_handle);
  if (pChildInfo) {
   if (pChildInfo->delay)
    cyg_thread_delay(pChildInfo->delay);
   cyg_thread_delete(pChildInfo->handle);
   memset(pChildInfo, 0, sizeof(*pChildInfo));
   pChildInfo = NULL;
  }
 }
 cyg_thread_exit();
}

cyg_bool_t Tell_Cleaner(PCHILD_INFO pInfo)
{
 if (cleaner_mbox_handle) {
  return cyg_mbox_put(cleaner_mbox_handle, (void *)pInfo);
 }
 return 0;
}