First working implementation of System V Semaphores with working tests. Check for comments inside the code

programs/tests/CMakeLists.txt

@@ -86,6 +86,7 @@ set(TESTS
     t_itimer.c
     t_gid.c
     t_semget.c
+    t_sem1.c
 )
 
 foreach(TEST ${TESTS})

programs/tests/t_sem1.c

@@ -0,0 +1,92 @@
+//test
+#include "ipc/sem.h"
+#include "stdio.h"
+#include "ipc/ipc.h"
+#include "sys/errno.h"
+#include "sys/wait.h"
+#include "stdlib.h"
+#include "sys/unistd.h"
+
+
+/*
+First test of System V Semaphores.
+Correct output should be: Corso di Sistemi Operativi.
+*/
+
+
+void semid_print(struct semid_ds *temp){
+    printf("pid, IPC_KEY, Semid, semop, change: %d, %d, %d, %d, %d\n", temp->owner, temp->key, temp->semid, temp->sem_otime, temp->sem_ctime);
+    for(int i=0; i<(temp->sem_nsems); i++){
+        printf("%d semaphore:\n", i+1);
+        printf("value: %d, pid %d, process waiting %d\n", temp->sems[i].sem_val, temp->sems[i].sem_pid, temp->sems[i].sem_zcnt);
+    }
+}
+
+int main()
+{
+	union semun arg;
+
+	struct sembuf sops[6];
+	sops[0].sem_num = 0;
+	sops[0].sem_op = -1;
+	sops[0].sem_flg = 0;
+
+	sops[1].sem_num = 1;
+	sops[1].sem_op = -1;
+	sops[1].sem_flg = 0;
+
+	sops[2].sem_num = 2;
+	sops[2].sem_op = -1;
+	sops[2].sem_flg = 0;
+
+	sops[3].sem_num = 0;
+	sops[3].sem_op = 1;
+	sops[3].sem_flg = 0;
+
+	sops[4].sem_num = 1;
+	sops[4].sem_op = 1;
+	sops[4].sem_flg = 0;
+
+	sops[5].sem_num = 2;
+	sops[5].sem_op = 1;
+	sops[5].sem_flg = 0;
+
+	int status;
+	//create a semaphore set
+	int semid = semget(IPC_PRIVATE, 4, IPC_CREAT);
+	//set the values of the semaphores 
+	unsigned short  values[] = {0,0,0,1};
+	arg.array = values;
+	if(semctl(semid,0,SETALL,&arg)==-1)
+		write(1,"errore set dei semafori",24);
+	
+	if(!fork()){
+		semop(semid, &sops[0], 1);
+		write(1,"Operativi.\n", 11);
+		exit(0);
+	}
+	if(!fork()){
+		semop(semid, &sops[1], 1);
+		write(1,"Sistemi ", 8);
+		semop(semid, &sops[3], 1);
+		exit(0);
+	}
+	if(!fork()){
+		semop(semid, &sops[2], 1);
+		write(1," di ", 4);
+		semop(semid, &sops[4], 1);
+		exit(0);
+	}
+	if(!fork()){
+		write(1,"Corso", 5);
+		semop(semid, &sops[5], 1);
+		exit(0);
+	}
+	for(int n=0; n<4; n++){
+		wait(&status);
+	}
+
+	if(semctl(semid,0,IPC_RMID,0)==-1)
+		write(1,"err", 3);
+    return 0;
+}

programs/tests/t_semget.c

@@ -3,15 +3,32 @@
 #include "stdio.h"
 #include "ipc/ipc.h"
 #include "sys/errno.h"
+#include "stdlib.h"
+#include "sys/unistd.h"
 
 
+/*
+Testing Semaphores.
+This program creates a son and then performs a blocking operation on a semaphore. The son sleeps for 
+five seconds and then it wakes up his father and then it deletes the semaphore.
+
+*/
+
+
+void semid_print(struct semid_ds *temp){
+    printf("pid, IPC_KEY, Semid, semop, change: %d, %d, %d, %d, %d\n", temp->owner, temp->key, temp->semid, temp->sem_otime, temp->sem_ctime);
+    for(int i=0; i<(temp->sem_nsems); i++){
+        printf("%d semaphore:\n", i+1);
+        printf("value: %d, pid %d, process waiting %d\n", temp->sems[i].sem_val, temp->sems[i].sem_pid, temp->sems[i].sem_zcnt);
+    }
+}
 
 int main()
 {      
     union semun arg;
-    arg.val = 150;    
+    arg.val = 1; 
     //key_t i = ftok("/test1.txt", 5);  //checking ftok
-    long id = semget(2,2,0);  //first semaphores
+    long id = semget(2,1,IPC_CREAT);  //first semaphores
     //long id2 = semget(IPC_PRIVATE, 1, IPC_CREAT);
     //long id2 = semget(2, 2, IPC_EXCL);  //need to return -1 bc already exists
 
@@ -19,13 +36,39 @@ int main()
 
     //long id4 = semget(100, 2, IPC_CREAT | IPC_EXCL);  //need to return 101 (new semaphore)
     long value;
-
-    if ((value = semctl(id, 1, SETVAL, arg)) == -1){
-        printf("%d \n", value);
+    printf("ID: %d\n", id);
+    if ((value = semctl(id, 0, SETVAL, &arg)) == -1){
+        printf("ERRORE\n");
     }else{
-        printf("getpid: %d\n", value);
+        //semid_print(arg.v);
+        printf("valore sem 0: %d  \n", semctl(id, 0, GETVAL, &arg));
     }
 
+
+
+    if (!fork()){
+        sleep(5);
+        struct sembuf op2;
+        op2.sem_num = 0;
+        op2.sem_op = 150;
+        op2.sem_flg = 0;
+        semop(id, &op2, 1);
+
+        semctl(id, 0, IPC_RMID, NULL);
+
+        exit(0);
+    }
+
+    struct sembuf op;
+    op.sem_num = 0;
+    op.sem_op = -1;
+    op.sem_flg = 0;
+    if (semop(id, &op, 2) < 0){
+        printf("ERRORE\n");
+    }
+    printf("valore sem 0: %d  \n", semctl(id, 0, GETVAL, &arg));
+    
+    
     /*if ((semid = semctl(id, 0, IPC_RMID, 0)) == -1){
         printf("%d\n", errno);
     }else{