1、Linux环境实验内容及实验结果请写出具体的实验步骤，并给出相应的实验结果，附上编写的程序及其运行结果截图!实验步骤：1。2. 3. #include #include sys/ipc.hsys/sem.hsys/shm.hstdlib.herrno.hstring.hsignal.h/* The union for semctl may or may not be defined for us.This code,defined in linuxs semctl（） manpage,is the proper way to attain it if necessary */#if defin
2、ed （_GNU_LIBRARY_）& !defined （_SEM_SEMUN_UNDEFINED）/* union semun is defined by including */#else/* according to X/OPEN we have to define it ourselves */union semunint val;/* value for SETVAL */struct semid_ds *buf;/* buffer for IPC_STAT,IPC_SET */unsigned short int *array;/* array for GETALL,SETALL
3、 */struct seminfo *_buf;/* buffer for IPC_INFO */;#endif#define SHMDATASIZE1000#define BUFFERSIZE （SHMDATASIZE - sizeof（int）#define SN_READ 0#define SN_WRITE 1#define SN_LOCK 2int Semid = 0;void reader（int shmid）;void writer（int shmid）;int masterinit（void）;char *standardinit（int shmid,int *semid）;vo
4、id delete（void）;void sigdelete（int signum）;void locksem（int semid,int semnum）;void unlocksem（int semid,int semnum）;void waitzero（int semid,int semnum）;void write（int shmid,int semid,char *buffer）;int mysemget（key_t key,int nsems,int semflg）;int mysemctl（int shmid,int semnum,int cmd,union semun arg）;
5、int mysemop（int semid,struct sembuf *sops,unsigned nsops）;int myshmget（key_t key,int size,int shmflg）;void *myshmat（int shmid,const void *shmaddr,int shmflg）;int myshmctl（int shmid,int cmd,struct shmid_ds *buf）;int main（int argc,char *argv）char selection3;int shmid;/* 没有参数,则为 master */if（argc 2）shmi
6、d = masterinit（）;elseshmid = atoi（argv1）;printf（ do you want a writer（1） or reader（2） ?）;fgets（selection,sizeof（selection）,stdin）;switch（selection0）case 1:writer（shmid）; break;2reader（shmid）;break;default: invalid choice, quit nreturn 0;void reader（int shmid）int semid;char *buffer;buffer = standardi
7、nit（shmid,&semid）;n reader begin to run， and the id of share memory is %d, semaphore id is %d n,shmid,semid）;while（1）n wait for writer to input information .fflush（stdout）;locksem（semid,SN_WRITE）;finish n wait for locking semaphore SN_LOCK .locksem（semid,SN_LOCK）;received information: %s n,buffer）;u
8、nlocksem（semid,SN_LOCK）;unlocksem（semid,SN_READ）;void writer（int shmid）writer begin to run，the id of share memory is %d, semaphore id is %dnchar input3;n menu n 1.send a message n 2.quit ninput your choice（1-2）:fgets（input,sizeof（input）,stdin）;switch（input0）write（shmid,semid,buffer）;exit（0）;char *st
9、andardinit（int shmid,int *semid）void *shmdata;shmdata = myshmat（shmid,0,0）;*semid = *（int *）shmdata;buffer = shmdata + sizeof（int）;return buffer;int masterinit（void）union semun sunion;int semid,shmid;/* 首先：我们要创建信号量 */semid = mysemget（IPC_PRIVATE,3,SHM_R|SHM_W）;Semid = semid;/* 当进程离开时，删除信号量 */atexit（
10、&delete）;signal（SIGINT,&sigdelete）;/* 信号量 SN_READ 初始化为 1（锁定），SN_WRITE 初始化为 0（未锁定）*/* 信号量 SN_LOCK 初始化为 1（锁定）*/ sunion.val = 1;mysemctl（semid,SN_READ,SETVAL,sunion）;mysemctl（semid,SN_LOCK,SETVAL,sunion）;sunion.val = 0;mysemctl（semid,SN_WRITE,SETVAL,sunion）;/* 现在创建一块共享内存 */shmid = myshmget（IPC_PRIVATE,
11、SHMDATASIZE,IPC_CREAT|SHM_R|SHM_W）;/* 将该共享内存映射进进程的虚存空间 */* 将该共享内存标志为已销毁的，这样在使用完毕后，将被自动销毁*/myshmctl（shmid,IPC_RMID,NULL）;/* 将信号量的标识符写入共享内存，以通知其它的进程 */*（int *）shmdata = semid;* begin to run, and semaphore id is %d n,shmid）;return shmid;void delete（void）n quit; delete the semaphore %d n,Semid）;union se
12、mun senion;senion.val=0;if（mysemctl（Semid,0,IPC_RMID,senion） = -1）Error releasing semaphore. nvoid sigdelete（int signum）/* Calling exit will conveniently trigger the normal delete item. */void locksem（int semid,int semnum）struct sembuf sb;sb.sem_num = semnum;sb.sem_op = -1;sb.sem_flg = SEM_UNDO;myse
13、mop（semid,&sb,1）;void unlocksem（int semid,int semnum）sb.sem_op = 1;void waitzero（int semid,int semnum）sb.sem_op = 0;sb.sem_flg = 0;/* No modification so no need to undo */void write（int shmid,int semid,char *buffer）n wait for reader to read in information .locksem（semid,SN_READ）;finish; wait for loc
14、king semaphore SN_LOCK.nplease input information:fgets（buffer,BUFFERSIZE,stdin）;unlocksem（semid,SN_WRITE）;int mysemget（key_t key,int nsems,int semflg）int retval;retval = semget（key,nsems,semflg）;if（retval = -1）semget key %d,nsems %d failed: %s ,key,nsems,strerror（errno）;exit（255）;return retval;int m
15、ysemctl（int semid,int semnum,int cmd,union semun arg）retval = semctl（semid,semnum,cmd,arg）;semctl semid %d,semnum %d,cmd %d failed: %s,semid,semnum,cmd,strerror（errno）; return retval;int mysemop（int semid,struct sembuf *sops,unsigned nsops）retval = semop（semid,sops,nsops）;semop semid %d （%d operatio
16、ns） failed:,semid,nsops,strerror（errno）;int myshmget（key_t key,int size,int shmflg）retval = shmget（key,size,shmflg）;shmget key %d,size %d failed:,key,size,strerror（errno）;void *myshmat（int shmid,const void *shmaddr,int shmflg）void *retval;retval = shmat（shmid,shmaddr,shmflg）;if（retval = （void*） -1）shmat shmid %d failed:,shmid,strerror（errno）;int myshmctl（int shmid,int cmd,struct shmid_ds *buf）retval = shmctl（shmid,cmd,buf）;shmctl shmid %d,cmd %d failed:,shmid,cmd,strerror（errno）;实验心得教师评阅意见教师签字签字日期年 月 日
