test13_a.c

进程间调度

#include "test13.h"
void fun_init(int *psem_id, int *pshm_id1, int *pshm_id2, int *pshm_id3, char **pshm_addr1, char **pshm_addr2);
void child_write(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2);
void child_read(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2, int num);
void resource_free(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2);
void sig_kill();
void sig_pause();

int b_kill, b_pause;       /*用于判断进程是否被要求退出或暂停*/
struct PInfo *shm_addr3;   /*共享内存3的首地址*/

int main()
{
 int sem_id, shm_id1, shm_id2, shm_id3;
 char *shm_addr1, *shm_addr2;  /*共享内存1、2的首地址*/
 int pid;
 int i, j;
 int sta;
 fun_init(&sem_id, &shm_id1, &shm_id2, &shm_id3, &shm_addr1, &shm_addr2);
 /*初始化函数，创建信号量和共享内存*/
 for(i=0; i<27; i++)
     shm_addr1[i] = '\0';               /*将共享内存1的内容初始化成'\0'*/
 for(i=0; i<4; i++)
     for(j=0; j<27; j++)
         shm_addr2[i*27 + j] = '\0';    /*将共享内存2的内容初始化成'\0'*/

 if((pid=fork()) == -1)                  /*创建一个写进程*/ 
   {
    printf("fork faild !!!\n");
    exit(0);
   }
 if(!pid)                               
   {
    b_kill = 0;
    b_pause = 0;
    signal(16, sig_kill);               /*定义要求进程退出运行的软中断处理函数*/
    signal(17, sig_pause);              /*定义要求进程暂停的软中断处理函数*/
    child_write(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
    exit(0);                            /*向共享内存1写字母的功能函数*/
   }
 else
   {
    for(i=1; i<=4; i++)                 /*创建4个读进程*/
       {
        pid = fork();
        switch(pid)
              {
               case -1:
                       printf("fork faild !!!\n");  
                       exit(0);
               case 0 :
                       b_kill = 0;
                       b_pause = 0;
                       signal(16, sig_kill);
                       signal(17, sig_pause);
                       child_read(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2, i); 
                       exit(0);   /*从共享内存1读字母，将其写入共享内存2中各自对应区域*/
               default:  
                       break;
              }
     }
   if(shmdt(shm_addr1) == -1)         /*与共享内存断开*/
      printf("shmdt faild !!!\n");
   if(shmdt(shm_addr2) == -1)
      printf("shmdt faild !!!\n");
   exit(0);
  }
}
/*
void fun_init(int *psem_id, int *pshm_id1, int *pshm_id2, int *pshm_id3, char ** pshm_addr1, char **pshm_addr2)

返回值：无
参数：psem_id,       int型指针，用于将创建的信号量集的ID返回给调用函数。
　　　pshm_id1,      int型指针，用于将创建的共享内存１的ID返回给调用函数。
　　　pshm_id2,      int型指针，用于将创建的共享内存2的ID返回给调用函数。　
      pshm_id3,      int型指针，用于将创建的共享内存3的ID返回给调用函数。
      pshm_addr1     char *型指针，用于将共享内存１的首地址返回给调用函数。
　　  pshm_addr2     char *型指针，用于将共享内存2的首地址返回给调用函数。
函数功能：创建一个包含３个信号量的信号量集，并创建３块共享内存。
*/
void fun_init(int *psem_id, int *pshm_id1, int *pshm_id2, int *pshm_id3, char ** pshm_addr1, char **pshm_addr2)
{
 int sta;
 union semun sem_v;
 *psem_id = semget(SEM_KEY, 3, IPC_CREAT|0600);
 if(*psem_id == -1)
   {
    printf("semget faild !!!\n");
    exit(0);
   }
 *pshm_id1 = shmget(SHM1_KEY, 27, IPC_CREAT|0600);
 if(*pshm_id1 == -1)
   {
    printf("shmget faild !!!\n");
    exit(0);
   }
 *pshm_id2 = shmget(SHM2_KEY, 27*4, IPC_CREAT|0600);
 if(*pshm_id2 == -1)
   {
    printf("shmget faild !!!\n");
    exit(0);
   }
 *pshm_id3 = shmget(SHM3_KEY, sizeof(struct PInfo)*5, IPC_CREAT|0600);
 if(*pshm_id3 == -1)
   {
    printf("shmget faild !!!\n");
    exit(0);
   }
 sem_v.val = 2;
 sta  = semctl(*psem_id, 0, SETVAL, sem_v);
 if(sta == -1)
   {
    printf("semctl faild !!!\n");
    exit(0);
   }
 sem_v.val = 4;
 sta = semctl(*psem_id, 1, SETVAL, sem_v);
 if(sta == -1)
   {
    printf("semctl faild !!!\n");
    exit(0);
   }
 sem_v.val = 1;
 sta = semctl(*psem_id, 2, SETVAL, sem_v);
 if(sta == -1)
   {
    printf("semctl faild !!!\n");
    exit(0);
   }
 *pshm_addr1 = shmat(*pshm_id1, 0, 0);
 if(!(*pshm_addr1))
   {
    printf("shmat faild !!!\n");
    exit(0);
   }
 *pshm_addr2 = shmat(*pshm_id2, 0, 0);
 if(!(*pshm_addr2))
   {
    printf("shmat faild !!!\n");
    exit(0);
   }
 
 }
/*
void child_write(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2)

返回值：无
参数：sem_id, 　 int型，信号量集的ID。
　　　shm_id1    int型，共享内存１的ID。
　　　shm_id2    int型，共享内存2的ID。
　　　shm_id3    int型，共享内存3的ID。
　　　shm_addr1  char型指针，共享内存１的首地址。
　　　shm_addr2  char型指针，共享内存２的首地址。
函数功能：向共享内存１写入26个英文字母，并在写进程结束运行时，调用resource_free()函数，
          使写进程与共享内存脱离，并在没有其他进程与共享内存相连时，销毁共享内存与信号量集。
*/
void child_write(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2)
{
 int sta;
 int i;
 struct sembuf sem_b[2];
 shm_addr3 = shmat(shm_id3, 0, 0);
 if(!shm_addr3)
   {
    printf("shmat faild in child_write() !!!\n");
    exit(0);
   }
 srand((int)time(0));
 shm_addr3[0].pid = getpid();
 shm_addr3[0].pstatus = 'R';
 sem_b[0].sem_num = 0;
 sem_b[0].sem_flg = SEM_UNDO;
 sem_b[1].sem_num = 2;
 sem_b[1].sem_flg = SEM_UNDO;
 for(i=0; i<26; i++)
    {
     if(b_kill)
       {
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        exit(0);
       }
     if(b_pause)
        pause();
     sem_b[0].sem_op = -2;
     sem_b[1].sem_op = -1;
     shm_addr3[0].pstatus = 'V';
     sta = semop(sem_id, sem_b, 2);
     if(sta == -1)
       {
        printf("semop faild in child_write() !!!\n");
        shm_addr3[0].pstatus = 'X';
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        exit(0);
       }
     shm_addr3[0].pstatus = 'R';
     shm_addr1[i] = 'a'+i;
     sleep(2);
     sem_b[0].sem_op = 2;
     sem_b[1].sem_op = 1;
     sta = semop(sem_id, sem_b, 2);
     if(sta == -1)
       {
        printf("semop faild in child_write() !!!\n");
        shm_addr3[0].pstatus = 'X';
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        exit(0);
       }
     sleep(1);
    }
   shm_addr3[0].pstatus = 'F';
   resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
}
/*
void child_read(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2, int num)

返回值：无
参数：sem_id，   int型，信号量集的ID。
　　　shm_id1    int型，共享内存１的ID。
　　　shm_id2    int型，共享内存2的ID。
　　　shm_id3    int型，共享内存3的ID。
　　  shm_addr1  char型指针，共享内存１的首地址。
　　　shm_addr2  char型指针，共享内存２的首地址。
      num        int型，取值范围{1,2,3,4}，用于对读进程的识别
函数功能：从共享内存１读取字符，并将其写入共享内存２中各个读进程各自对应的区域。
          在读进程结束时，调用resource_free()函数，读进程与共享内存脱离，并在没有其他进程与共享内存相连时，销毁共享内存与信号量集。
*/ 
void child_read(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2, int num)
{
 struct sembuf  sem_b[2];
 int sta;
 int i;
 shm_addr3 = shmat(shm_id3, 0, 0);
 if(!shm_addr3)
   {
    printf("shmat faild in child_read() !!!\n");
    exit(0);
   }
 srand(300*num  + (int)time(0));
 shm_addr3[num].pid = getpid();
 shm_addr3[num].pstatus = 'R';
 sem_b[0].sem_num = 0;
 sem_b[0].sem_flg = SEM_UNDO;
 sem_b[1].sem_num = 1;
 sem_b[1].sem_flg = SEM_UNDO;
 for(i=0; i<26; i++)
    {
     if(b_kill)
       {
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        exit(0);
       }
     if(b_pause)
        pause();
     sem_b[0].sem_op = -1;
     sem_b[1].sem_op = -1;
     shm_addr3[num].pstatus = 'V';
     sta = semop(sem_id, sem_b, 2);
     if(sta == -1)
       {
        printf("semop faild in child_read()!!!\n");
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        shm_addr3[num].pstatus = 'X';
        exit(0);
       }
     shm_addr3[num].pstatus = 'R';
     if(shm_addr1[i] != '\0')
        shm_addr2[27*(num-1) + i] = shm_addr1[i];
     else
        i--;
     sem_b[0].sem_op = 1;
     sem_b[1].sem_op = 1;
     sta = semop(sem_id, sem_b, 2);
     if(sta == -1)
       {
        printf("semop faild in child_read()!!!\n");
        shm_addr3[num].pstatus = 'X';
        resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
        exit(0);
       }
     sleep((rand()%5)+1); 
    }
  shm_addr3[num].pstatus = 'F';
  resource_free(sem_id, shm_id1, shm_id2, shm_id3, shm_addr1, shm_addr2);
}
/*
void resource_free(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2)

返回值：无
参数：sem_id，   int型，信号量集的ID。
　　  Shm_id1    int型，共享内存１的ID。
　　　Shm_id2    int型，共享内存2的ID。
　　  Shm_id3    int型，共享内存3的ID。
　　　Shm_addr1  char型指针，共享内存１的首地址。
　　　Shm_addr2  char型指针，共享内存２的首地址。
函数功能：在每个读写进程退出时被调用，用于调用进程的与共享内存脱离，若没有其他进程与共享内存相连，则销毁共享内存与信号量集。
*/
void resource_free(int sem_id, int shm_id1, int shm_id2, int shm_id3, char *shm_addr1, char *shm_addr2)
{
 int k;
 int sta;
 struct shmid_ds shm_buf;
 k=0;
 if(shmdt(shm_addr1) == -1)
    printf("shmdt faild in resource_free() !!!\n");
 sta = shmctl(shm_id1, IPC_STAT, &shm_buf);
 if(sta == -1)
    printf("shmctl faild in resource_free() !!!\n");
 else
   {
    if(shm_buf.shm_nattch == 0)
      {
       k++;  
       sta = shmctl(shm_id1, IPC_RMID, 0);
       if(sta == -1)
          printf("shmctl faild in resource_free() !!!\n");
      } 
   } 
 if(shmdt(shm_addr2) == -1)
    printf("shmdt faild in resource_free() !!!\n");
 sta = shmctl(shm_id2, IPC_STAT, &shm_buf);
 if(sta == -1)
    printf("shmctl faild in resource_free() !!!");
 else
   {
    if(shm_buf.shm_nattch == 0)
      {
       k++;
       sta = shmctl(shm_id2, IPC_RMID, 0);
       if(sta == -1)
          printf("shmctl faild in resource_free() !!!\n");
      }
   }
 if(shmdt(shm_addr3) == -1)
    printf("shmdt faild in resource_free() !!!\n");
 sta = shmctl(shm_id3, IPC_STAT, &shm_buf);
 if(sta == -1)
    printf("shmctl faild in resource_free() !!!\n");
 else
   {
    if(shm_buf.shm_nattch == 0)
      {
       k++;
       sta = shmctl(shm_id3, IPC_RMID, 0);
       if(sta == -1)
          printf("shmctl faild in resource_free() !!!\n");
      }
   }
 if(k == 3)
   {
    sta = semctl(sem_id, 3, IPC_RMID, 0);
    if(sta == -1)
       printf("semctl faild in resource_free() !!!\n");
   }
}
/*
void sig_kill()

返回值：无
参数：　无
函数功能：收到监控程序发来的结束进程运行的信号时，所执行的软中断处理函数。
*/
void sig_kill()
{
 int i;
 b_kill = 1;
 for(i=0; i<=4; i++)
     if(shm_addr3[i].pid == getpid())
        break;
 shm_addr3[i].pstatus = 'X';
}
/*
void sig_pause()

返回值：无
参数：　无
函数功能：收到监控程序发来的暂停进程运行的信号时，所执行的软中断处理函数。
*/
void sig_pause()
{
 int i;
 for(i=0; i<=4; i++)
     if(shm_addr3[i].pid == getpid())
        break;
 if(b_pause == 0)
   {
    b_pause = 1;
    shm_addr3[i].pstatus = 'P';
   }
 else
   {
    b_pause = 0;
    shm_addr3[i].pstatus = 'R';
   }
}