UNIX for Advanced & Expert Users

Control two exclusively shared resources(semaphore). The two resources are two files. The producer will write even numbers to one file, and odd numbers to another one. The consumer respectively reads from each file until it gets 5 even numbers and 5 odd numbers.

Can any one help me with the code.

Thanks in advance.

Producer
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#define PUB7645 "./PubFile"
union semun {
int val;
struct semid_ds *buf;
ushort *array;
};
int
main() {
int i=0, intValue, semID;
key_t key;
FILE *fptr;
union semun arg;
static ushort startVal[2] = {1, 0};
static struct sembuf acquire = {0, -1, SEM_UNDO},
release = {1, 1, SEM_UNDO};
key = ftok(".", 's');
if ((semID = semget(key, 2, IPC_CREAT | 0666)) == -1) {
perror("Sem Creation:");
exit(2);
}
arg.array = startVal;
if (semctl(semID, 2, SETALL, arg) == -1 ) {
perror("semctl: SETALL");
exit(3);
}
for( ; ; ) {
srand(getpid()+i);
intValue =rand()*49/RAND_MAX + 1;
if (semop(semID, &acquire, 1) == -1) {
perror("Producer waiting");
exit(4);
}
if ((fptr = fopen(PUB7645, "w")) == NULL) {
perror(PUB7645);
exit(1);
}fprintf(fptr, "%d\n", intValue);
fclose(fptr);
if (semop(semID, &release, 1) == -1) {
perror("new");
exit(5);
}
i++;
}
}

Consumer


#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#define PUB7645 "./PubFile"
union semun {
int val;
struct semid_ds *buf;
ushort *array;
};
int main() {
int i=0, intValue, semID;
key_t key;
FILE *fptr;
union semun arg;
static struct sembuf acquire = {1, -1, SEM_UNDO},
release = {0, 1, SEM_UNDO};
key = ftok(".", 's');
if ((semID = semget(key, 2, IPC_CREAT | 0666)) == -1) {
perror("Sem Creation:");
exit(2);
}
for(i=1; i<=5 ; i++) {
if (semop(semID, &acquire, 1) == -1) {
perror(“Consumer waiting");
exit(4);
}
if ((fptr = fopen(PUB7645, "r")) == NULL) {
perror(PUB7645);
exit(1);
}
fscanf(fptr, "%d", &intValue);
fclose(fptr);
if (semop(semID, &release, 1) == -1) {
perror(“Release");
exit(4);
}
printf("%d\t", intValue);
}
printf("\nI am process %d. I got five numbers ", getpid());
printf("from a producer as above.\n");
}