操作系统-进程控制

来源：互联网发布：盗梦侦探知乎编辑：程序博客网时间：2024/04/29 01:22
附录1.进程的创建#include<stdio.h>#include<stdlib.h>main(){        int p1,p2;if(p1=fork())               /*父进程创建成功*/    putchar('b');else{ if(p2=fork())              /*父进程创建成功*/  putchar('c');    else putchar('a');           /*子进程执行*/}}2.进程的互斥1>同步#include<stdio.h>#include<stdlib.h>main(){int p1,p2,i;if(p1=fork()){ for(i=0;i<500;i++)printf("parent%d\n",i);        wait(0); /* 保证在子进程终止前，父进程不会终止*/exit(0); /*  结束该进程*/}else{  if(p2=fork()){    for(i=0;i<500;i++)         printf("son %d\n",i);                wait(0); /* 保证在子进程终止前，父进程不会终止*/exit(0); /* 向父进程信号0且该进程退出*/} else{    for(i=0;i<500;i++)  printf(“grandchild %d\n",i); exit(0);}}}2>互斥 #include<stdio.h>#include<stdlib.h>main(){int p1,p2,i;if(p1=fork()){     lockf(1,1,0);/*对父进程进行加锁，实现互斥*/     for(i=0;i<500;i++)  printf("parent %d\n",i);     lockf(1,0,0);/*对父进程进行解锁*/      wait(0); /* 保证在子进程终止前，父进程不会终止*/      exit(0); /*  结束该进程*/}else {  if(p2=fork()){ lockf(1,1,0);/*对父进程进行加锁，实现互斥*/     for(i=0;i<500;i++)             printf("son %d\n",i);    lockf(1,0,0);/*对父进程进行解锁*/         wait(0); /* 保证在子进程终止前，父进程不会终止*/exit(0);  }else{  lockf(1,1,0);/*对子进程进行加锁，实现互斥*/      for(i=0;i<500;i++)          printf("grandchild %d\n",i);       lockf(1,0,0);/*对子进程进行解锁*/    exit(0);} }}3.进程的软中断通信#include<stdio.h>#include<signal.h>#include<unistd.h> void waiting(),stop(),alarming();int wait_mark;main(){int p1,p2;if(p1=fork())             /*创建子进程p1*/{if(p2=fork())    /*创建子进程p2*/{wait_mark=1;signal(SIGINT,stop);    /*父进程接收到^c信号，转stop*/signal(SIGALRM,alarming);/*接受SIGALRM，并调用alarming方法            waiting();            while (wait_mark!=0);kill(p1,16);            /*向p1发软中断信号16*/   kill(p2,17);           /*向p2发软中断信号17*/        wait(0);             /*等待子进程p2，实现同步*/wait(0);             /*等待子进程p1，实现同步*/printf("parent process is killed!\n");exit(0);    }else    {wait_mark=1;signal(17,stop);signal(SIGINT,SIG_IGN);  /*子进程忽略 ^c信号*/while (wait_mark!=0);   lockf(1,1,0);           /*为子进程加锁，实现互斥*/printf("child process2  is killed by parent!\n");lockf(1,0,0);           /*为子进程解锁*/exit(0);}}else{wait_mark=1;signal(16,stop);signal(SIGINT,SIG_IGN);  /*忽略^c信号*/while (wait_mark!=0)lockf(1,1,0);            /*为子进程加锁，实现互斥*/printf("child process1 is killed by parent!\n");lockf(1,0,0);            /*为子进程解锁*/exit(0);}}void waiting(){sleep(5);if (wait_mark!=0) kill(getpid(),SIGALRM);     /*获得想要中断的进程号，并返回SIGALRM*/}void alarming(){wait_mark=0;}void stop(){wait_mark=0;}4.进程的管道通信#include <unistd.h>#include <signal.h>#include <stdio.h>int pid1,pid2; main( ){ int fd[2];                       /*为管道定义输入端和输出端*/char outpipe[100],inpipe[100];pipe(fd);                       /*创建一个无名管道*/while ((pid1=fork( ))==-1);         /*进程创建失败*/if(pid1==0)  {lockf(fd[1],1,0);             /*fd[1]写入端加锁*/sprintf(outpipe,"child 1 process is sending message!"); /*将数据放入定义好的缓冲区数组                                             outpipe内*/                    write(fd[1],outpipe,50);     /*向管道写长为50字节的串*/sleep(5);                 /*自我阻塞5秒，让所显示的内容休眠5秒钟，即等待5秒                         钟再显示。子进程pid1和子进程pid2也能对管道进行操作，                        因为他们同属于共同的管道共同共享资源*/ lockf(fd[1],0,0);          /*写入端解锁*/    exit(0);   }else  {while((pid2=fork( ))==-1);    if(pid2==0){ lockf(fd[1],1,0);           /*fd[1]写入端加锁*/        sprintf(outpipe,"child 2 process is sending message!");        write(fd[1],outpipe,50);        sleep(5);        lockf(fd[1],0,0);        exit(0);     }     else     {  wait(0);              /*实现进程间的同步*/         read(fd[0],inpipe,50);   /*从fd[0]端口读出50字节的数据送到inpipe指向的缓冲 */         printf("%s\n",inpipe);         wait(0);         read(fd[0],inpipe,50);         printf("%s\n",inpipe);        exit(0);    }  }}5.进程间消息的创建、发送和接收#include <stdio.h> #include <sys/types.h>#include <sys/msg.h>#include <sys/ipc.h>#define MSGKEY 75          /*定义关键词MEGKEY*/struct msgform              /*消息结构*/{long mtype;char mtexe[100];         /*文本长度*/}msg;int msgqid,i;void CLIENT( ){int i;msgqid=msgget(MSGKEY,0777|IPC_CREAT);   /*通过关键字获得队列*/for(i=10;i>=1;i--){ msg.mtype=i; printf("(client)sent\n");  msgsnd(msgqid,&msg,1030,0);       /*发送消息msg入msgid消息队列,1030                                          为消息的长度*/}exit(0);}void SERVER( ){   msgqid=msgget(MSGKEY,0777|IPC_CREAT); /*创建消息队列*/  do  {  msgrcv(msgqid,&msg,1030,0,0);  /*从队列msgid接受长度为1030的消息msg*/  printf("(server)receive\n");  }while(msg.mtype!=1);             /*消息类型为1时，释放队列*/   msgctl(msgqid, IPC_RMID,0);       /*删除msgqid的消息队列*/}main(){  if(fork()) {SERVER();                   /*创建父进程*/  wait(0);}else CLIENT( );                 /*创建的子进程*/}6.进程共享存储区的创建、附接和断接#include<sys/types.h>#include<sys/msg.h>#include<sys/ipc.h>#define SHMKEY  75                   /*定义共享区关键词*/int shmid,i;int *addr; CLIENT(){int i;shmid=shmget(SHMKEY,1024, 0777|IPC_CREAT);    /*获取共享区，长度1024，关键词                                                 SHMKEY*/addr=shmat(shmid,0,0);                /*获取共享区起始地址addr*/for(i=9;i>=0;i--) {while(*addr!= -1);                  printf("(client)sent\n");                 /*打印（client）sent*/*addr=i;                             /*把i赋给addr*/}exit(0);}SERVER(){ do{while(*addr = =-1);printf("(server)received\n%d",*addr);               /*服务进程使用共享区*/if(*addr!=0)*addr=-1;} while(*addr);    wait(0);shmctl(shmid,IPC_RMID,0);                        /*撤销共享存储区，归还资源*/} main(){shmid=shmget(SHMKEY,1024,0777|IPC_CREAT);      /*创建共享区*/addr=shmat(shmid,0,0);                         /*共享区起始地址为addr*/*addr=-1;if(fork()){ SERVER();}else{ CLIENT();} }7.处理器调度 #include<stdio.h>#include<stdlib.h>#include<time.h>struct PCB *head,*tail;//这里是全局的int global_time = 0;            //全局时间  struct PCB{char name[10];         //进程名字struct PCB *next;       //下一个PCB指针int run_time;          //运行时间int priority;           //优先级char status;          //目前状态};struct PCB* initPCB(struct PCB *p, int i){p->name[0] = 'P';p->name[1] = i + '0';p->name[2] = 0;p->next = NULL;printf("Process %s\n", p->name);printf("input run_time: ");scanf("%d", &p->run_time);printf("input priority: ");scanf("%d", &p->priority);/*p->run_time = i+1;p->priority = i;p->status = 'R';*/return p;}//输入任务名称， 时间和优先级，运行状态为E void run(struct PCB *p){printf("Process: %s, running @ tim %d, priority %d, run_time  %d\n",p->name, global_time, p->priority, p->run_time);global_time++;p->run_time--;if(p->priority > 0)p->priority--;}//输出这个任务的状态，全局时间加1，任务还需要的时间减1，优先 级减1 void SortChain(struct PCB *phead,struct PCB *ptail){struct PCB *pMax,*pMaxPre,*pPre,*pTemp;head= tail = NULL;//再初始化 一次，重新把排列好的结点加入到链 表中pPre = pMax= pMaxPre = NULL;//pMax：priority 最大的那个结点，  pMaxPre:pMax前个结点或许用双向链 表更好一些if(phead == NULL){head = tail = NULL;return ;}else{while(phead != NULL){pMax= phead;pMaxPre = phead;for(pTemp = phead;pTemp != NULL; pTemp =  pTemp->next){if(pTemp->priority > pMax->priority  ){pMax = pTemp;pMaxPre = pPre;}pPre= pTemp;}if(pMax == phead){phead = phead->next;}else{pMaxPre->next = pMax->next ;}pMax ->next = NULL;if(head == NULL){tail = head = pMax;}else{tail -> next = pMax;tail= pMax;}}}}int main(void ){int i;struct PCB *p = NULL, *q = NULL;//定义指针p和q，p为待运行队列PCB指针，q为待插入队列PCB指针 head = tail = NULL;for(i = 0;i < 5;i ++){p = (struct PCB *)malloc(sizeof(struct PCB)); //分配空间，让p指向这个PCBinitPCB(p,i);p -> next = NULL;if(head == NULL){// 首先把进 程 链表排列起来！ 不一定按照 priority  顺序tail = head = p;}else{tail -> next = p;tail= p;}}SortChain(head,tail);/// 按照 priority顺序排列结点while(head != NULL){//当头节点不为空即链表中还有PCB的时候 printf("Current state:\n");for(p = head; p != NULL; p = p->next){printf("Process %s, priority: %d, run_time  %d\n",p->name, p->priority, p->run_time);}                 //让p指针从 head->next 开始走到末尾，输出每一个状态 p = head;run(p);//p指向第一个PCB，然后进行调度 if(p->run_time <= 0){printf("Process %s ends.\n", p->name);p->status = 'E';///free(p);///这里就不释放了head = p-> next;}               //如果PCB已经结束，输出信息，释放空间 ，进行下一轮 循环 SortChain(head,tail);//按照  priority  顺序 排列结点}                               //如果还需要运行，将PCB插入合适位置 system("pause");return 0;}
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