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完整的代码如下
#include <sys/types.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#define SHMDATASIZE 1000
#define BUFFERSIZE (SHMDATASIZE-sizeof(int))
#define SN_EMPTY 0
#define SN_FULL 1
int deleteSemid = 0;
void server(void);
void client(int shmid);
void 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 clientwrite(int shmid,int semid,char*buffer);
int safesemget(key_t key,int nsems,int semflg);
int safesemctl(int semid,int semnum,int cmd,union semun arg);
int safesemop(int semid,struct sembuf *sops,unsigned nsops);
int safeshmget(key_t key,int size,int shmflg);
int safeshmat(int shmid,const void *shmaddr,int shmflg);
int safeshmctl(int shmid,int cmd,struct shmid_ds *buf);
typedef union semun
{
int val;
struct semid_ds *buf;
ushort array;
};
int main(int argc,char *argv[])
{
if (argc < 2)
sever();
else
client(atoi(argv[1]));
return 0;
}
void server (void)
{
union semun sunion;
int semid,shmid;
void *shmdata;
char *buffer;
semid = safesemget(IPC_PRIVATE,2,SHM_R|SHM_W);
deleteSemid = semid;
atexit(&delete);
signal(SIGINT,&sigdelete);
sunion.val = 1;
safesemctl(semid,SN_EMPTY,SETVAL,sunion);
sunion.val = 0;
safesemctl(semid,SN_FULL,SETVAL,sunion);
shmid = safeshmget(IPC_PRIVATE,SHMDATASIZE,IPC_CREAT|SHM_R|SHM_W);
shmdata = safeshmat(shmid,0,0);
safeshmctl(shmid,IPC_RMID,NULL);
*(int*)shmdata = semid;
buffer = shmdata+sizeof(int);
printf("Server is running with SHM id **%d**\n",shmid);
while(1)
{
printf("Waiting until full...");
fflush(stdout);
locksem(semid,SN_FULL);
printf("done.\n");
printf("Message received:%s.\n",buffer);
unlocksem(semid,SN_EMPTY);
}
}
void client(int shmid)
{
int semid;
void *shmdata;
char *buffer;
shmdata = safeshmat(shmid,0,0);
semid = *(int*)shmdata;
buffer = shmdata-sizeof(int);
printf("Client operational;shm id is %d,sem id is %d\n",shmid ,semid);
while(1)
{
char input[3];
printf("\n\nMenu\n1.Send a message|n");
printf("2.Exit\n");
fgets(input,sizeof(input),stdin);
switch(input[0])
{
case'1':
clientwrite(shmid,semid,buffer);
break;
case'2':
exit(0);
break;
}
}
}
void delete(void)
{
printf("\nMaster exiting;deleting semaphore %d. \n",deleteSemid);
if (semctl(deleteSemid,0,IPC_RMID,0) == -1)
printf("Error releasing semaphore.\n");
}
void sigdelete(int signum)
{
exit(0);
}
void locksem(int semid,int semnum)
{
struct sembuf sd;
sd.sem_num = semnum;
sd.sem_op = -1;
sd.sem_flg = SEM_UNDO;
safesemop(semid,&sd,1);
}
void unlocksem(int semid,int semnum)
{
struct sembuf sd;
sd.sem_num = semnum;
sd.sem_op = 1;
sd.sem_flg = SEM_UNDO;
safesemop(semid,&sd,1);
}
void waitzero(int semid,int semnum)
{
struct sembuf sd;
sd.sem_num = semnum;
sd.sem_op = 0;
sd.sem_flg = 0;
safesemop(semid,&sd,1);
}
void clientwrite(int shmid,int semid,char *buffer)
{
printf("Waiting until empty...");
fflush(stdout);
locksem(semid,SN_EMPTY);
printf("done.\n");
printf("Enter Message:");
fgets(buffer,BUFFERSIZE,stdin);
unlocksem(semid,SN_FULL);
}
int safesemget(key_t key,int nsem,int semflg)
{
int retval;
if (retval = semget(key,nsem,semflg) == -1)
{
printf("semget error:%s.\n",sys_errlist[errno]);
exit(254);
}
return retval;
}
int safesemop(int semid,struct sembuf *sops,unsigned nsops)
{
int retval;
if (retval = semop(semid,sops,nsops) == -1)
{
printf("semop error:%s.\n",sys_errlist[errno]);
exit(254);
}
return retval;
}
int safeshmget(key_t key,int size,int shmflg)
{
int retval;
if (retval = shmget(key,size,shmflg) == -1)
{
printf("shmget error:%s.\n",sys_errlist[errno]);
exit(254);
}
return retval;
}
int safeshmat(int shmid,const void *shmaddr,int shmflg)
{
int retval;
if ((retval = shmat(shmid,shmaddr,shmflg))== -1)
{
printf("shmat error:%s.\n",sys_errlist[errno]);
exit(254);
}
return retval;
}
int safeshmctl(int shmid,int cmd,struct shmid_ds *buf)
{
int retval;
if (retval = shmctl(shmid,cmd,buf) == -1)
{
printf("shmctl error:%s.\n",sys_errlist[errno]);
exit(254);
}
return retval;
}
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发表于 2013-09-17 23:17
