IO进程线程DAY 9
作业一：
msg_1.c：
#include
#include
#include
#include
#include
typedef struct msgbuf
{
long mtype;// >0
char mtext[128];
}Msgbuf;
void *thread_r(void *);
void *thread_w(void *);
key_t key;
int msqid;
pthread_t tid_r, tid_w;
Msgbuf msgbuf_r, msgbuf_w;
long myType = 1;
long otherType = 2;
int mask = 2;
int main(int argc, char const *argv[])
{
// 1. ftok
key = ftok("./", mask);// 8bit
if(key < 0)
{
perror("ftok");
return -1;
}
else
{
printf("ftok : success with key %d.\n", key);
}
// 2. msgget
msqid = msgget(key, IPC_CREAT|0777);
if(msqid < 0)
{
perror("msgget");
return -1;
}
else
{
printf("msgget : success with msqid %d.\n", msqid);
}
// thread r and w
if(pthread_create(&tid_r, NULL, thread_r, NULL) < 0)
{
perror("pthread_create");
return -1;
}
else
{
printf("pthread_create : success with tid_r %ld.\n", tid_r);
}
if(pthread_create(&tid_w, NULL, thread_w, NULL) < 0)
{
perror("pthread_create");
return -1;
}
else
{
printf("pthread_create : success with tid_w %ld.\n", tid_w);
}
// block main thread
pthread_join(tid_r, NULL);
pthread_join(tid_w, NULL);
// msgctl
if(msgctl(msqid, IPC_RMID, NULL) < 0)
{
perror("msgctl");
return -1;
}
else
{
printf("msgctl : msgqueue exit success.\n");
}
return 0;
}
void *thread_r(void *arg)
{
// msgrcv
while(1)
{
bzero(msgbuf_r.mtext, sizeof(msgbuf_r.mtext));
msgrcv(msqid, &msgbuf_r, sizeof(msgbuf_r.mtext), otherType, 0);
if(0 == strcasecmp(msgbuf_r.mtext, "quit"))
{
pthread_cancel(tid_w);
break;
}
printf("read from msg_2 >>> %s\n", msgbuf_r.mtext);
}
pthread_exit(NULL);
}
void *thread_w(void *arg)
{
while(1)
{
// printf("Please input >>> ");
msgbuf_w.mtype = myType;
// scanf("%ld %s", msgbuf_w.mtype, msgbuf_w.mtext);
// scanf("%s", msgbuf_w.mtext);
fgets(msgbuf_w.mtext, sizeof(msgbuf_w.mtext), stdin);
msgbuf_w.mtext[strlen(msgbuf_w.mtext)-1] = 0;
msgsnd(msqid, &msgbuf_w, sizeof(msgbuf_w.mtext), IPC_NOWAIT);
if(0 == strcasecmp(msgbuf_w.mtext, "quit"))
{
pthread_cancel(tid_r);
break;
}
}
pthread_exit(NULL);
} msg_2.c
#include
#include
#include
#include
#include
typedef struct msgbuf
{
long mtype;// >0
char mtext[128];
}Msgbuf;
void *thread_r(void *);
void *thread_w(void *);
key_t key;
int msqid;
pthread_t tid_r, tid_w;
Msgbuf msgbuf_r, msgbuf_w;
long myType = 2;
long otherType = 1;
int mask = 2;
int main(int argc, char const *argv[])
{
// 1. ftok
key = ftok("./", mask);// 8bit
if(key < 0)
{
perror("ftok");
return -1;
}
else
{
printf("ftok : success with key %d.\n", key);
}
// 2. msgget
msqid = msgget(key, IPC_CREAT|0777);
if(msqid < 0)
{
perror("msgget");
return -1;
}
else
{
printf("msgget : success with msqid %d.\n", msqid);
}
// thread r and w
if(pthread_create(&tid_r, NULL, thread_r, NULL) < 0)
{
perror("pthread_create");
return -1;
}
else
{
printf("pthread_create : success with tid_r %ld.\n", tid_r);
}
if(pthread_create(&tid_w, NULL, thread_w, NULL) < 0)
{
perror("pthread_create");
return -1;
}
else
{
printf("pthread_create : success with tid_w %ld.\n", tid_w);
}
// block main thread
pthread_join(tid_r, NULL);
pthread_join(tid_w, NULL);
// msgctl
if(msgctl(msqid, IPC_RMID, NULL) < 0)
{
perror("msgctl");
return -1;
}
else
{
printf("msgctl : msgqueue exit success.\n");
}
return 0;
}
void *thread_r(void *arg)
{
// msgrcv
while(1)
{
bzero(msgbuf_r.mtext, sizeof(msgbuf_r.mtext));
msgrcv(msqid, &msgbuf_r, sizeof(msgbuf_r.mtext), otherType, 0);
if(0 == strcasecmp(msgbuf_r.mtext, "quit"))
{
pthread_cancel(tid_w);
break;
}
printf("read from msg_1 >>> %s\n", msgbuf_r.mtext);
}
pthread_exit(NULL);
}
void *thread_w(void *arg)
{
while(1)
{
// printf("Please input >>> ");
msgbuf_w.mtype = myType;
// scanf("%ld %s", msgbuf_w.mtype, msgbuf_w.mtext);
// scanf("%s", msgbuf_w.mtext);
fgets(msgbuf_w.mtext, sizeof(msgbuf_w.mtext), stdin);
msgbuf_w.mtext[strlen(msgbuf_w.mtext)-1] = 0;
msgsnd(msqid, &msgbuf_w, sizeof(msgbuf_w.mtext), IPC_NOWAIT);
if(0 == strcasecmp(msgbuf_w.mtext, "quit"))
{
pthread_cancel(tid_r);
break;
}
}
pthread_exit(NULL);
} 运行截图：
作业二：
shm_print.c
#include
#include
#include
#include
#include
size_t shmSize = 32;
int main(int argc, char const *argv[])
{
// 1. ftok
key_t key = ftok("./", 1);
if(key < 0)
{
perror("ftok");
return -1;
}
else
{
printf("ftok : success with key %d.\n", key);
}
// 2. shmid
int shmid = shmget(key, shmSize, IPC_CREAT | 0777);
if(shmid < 0)
{
perror("shmget");
return -1;
}
else
{
printf("shmget : success with shmid %d.\n", shmid);
}
// 4. shmat
char *shmaddr = (char *)shmat(shmid, NULL, 0);
if((void *)shmaddr < 0)
{
perror("shmat");
return -1;
}
else
{
printf("shmat : linked with addr %p.\n", shmaddr);
}
// write
bzero(shmaddr, shmSize);
char *pflag= shmaddr;
*pflag = 1;
// 1 >>> can be reversed
// 0 >>> can be printed
char *phead = pflag+1;
strcpy(phead, "1234567");
// print
while(1)
{
if(0 == *pflag)
{
printf("%s\n", phead);
*pflag = 1;
}
}
// following code won't run
// 5. shmdt
if(shmdt(shmaddr) < 0)
{
perror("shmdt");
return -1;
}
else
{
printf("shmdt : link closed.\n");
}
// 3. shmctl
if(shmctl(shmid, IPC_RMID, NULL) < 0)
{
perror("shmctl");
return -1;
}
else
{
printf("shmctl : shared memory destroyed...\n");
}
return 0;
}
shm_reverse.c
#include
#include
#include
#include
#include
int main(int argc, char const *argv[])
{
// 1. ftok
key_t key = ftok("./", 1);
if(key < 0)
{
perror("ftok");
return -1;
}
else
{
printf("ftok : success with key %d.\n", key);
}
// 2. shmid
int shmid = shmget(key, 32, IPC_CREAT | 0777);
if(shmid < 0)
{
perror("shmget");
return -1;
}
else
{
printf("shmget : success with shmid %d.\n", shmid);
}
// 4. shmat
char *shmaddr = (char *)shmat(shmid, NULL, 0);
if((void *)shmaddr < 0)
{
perror("shmat");
return -1;
}
else
{
printf("shmat : linked with addr %p.\n", shmaddr);
}
// write
char *pflag= shmaddr;
// 1 >>> can be reversed
// 0 >>> can be printed
char *phead = pflag+1;
char *ptail = pflag+strlen(phead);
char temp = 0;
// print
struct shmid_ds buf;
int count = 0;
while(1)
{
if(1 == *pflag)
{
while(phead < ptail)
{
temp = *phead;
*phead = *ptail;
*ptail = temp;
phead++;
ptail--;
}
phead = pflag+1;
ptail = pflag+strlen(phead);
*pflag = 0;
count++;// notice count overflow
// 很多其它方法：如共享内存中写入pid通过kill和signal组合
}
shmctl(shmid, IPC_STAT, &buf);
if(1 == buf.shm_nattch && count)
{
printf("while exit.\n");
break;
}
}
// 5. shmdt
if(shmdt(shmaddr) < 0)
{
perror("shmdt");
return -1;
}
else
{
printf("shmdt : link closed.\n");
}
// 3. shmctl
if(shmctl(shmid, IPC_RMID, NULL) < 0)
{
perror("shmctl");
return -1;
}
else
{
printf("shmctl : shared memory destroyed...\n");
}
return 0;
}
运行截图：
