Upload batch 343 of 407

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 10 - Shared Memory/shm4.c

@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <string.h>
+#include <sys/sem.h>
+
+union semun
+{
+    int val;
+    struct semid_ds * buff;
+    unsigned short *array;
+    struct seminfo *_buf;
+};
+
+char *sharestr;
+int shmid, s;
+
+int semid; 
+union semun semarg,semarg2;
+int i;
+struct sembuf sops[1];// see declaration of sembuf in Google
+
+void main()
+{
+       semid = semget ( IPC_PRIVATE , 1 , 0600 );// 1- create only one semaphore
+       semarg.val = 1;//semaphore is unlocked
+       semctl ( semid , 0 , SETVAL , semarg );// 0 - only one semaphore . SETVAL - the command
+
+       shmid = shmget ( IPC_PRIVATE , 100, 0600 );// the size of the shared memory is 100 bytes
+       if ( fork()==0 ) {
+             printf ("child : try to lock the semapore \n");
+             sops->sem_op = -1; // decrease the sem. from 0 to 1
+             sops->sem_num = 0;
+             sops->sem_flg = 0;
+             semop ( semid , sops , 1 ); // operate the increase
+             int val = semctl(semid,0,GETVAL,semarg);
+             
+             printf ("child : semapore is locked now. the semaphore value is %d\n",val);
+	     sharestr=(char *)shmat ( shmid , NULL , 0600 );
+             strcpy ( sharestr , "Writing something to shared memory" );
+             shmdt ( sharestr );
+             
+             sops->sem_op = 1; // increase the sem. from 0 to 1 . unlock the sempahore
+             sops->sem_num = 0;
+             sops->sem_flg = 0;
+             semop ( semid , sops , 1 ); // operate the increase*/
+             int val2 = semctl(semid,0,GETVAL,semarg);
+             
+             printf ("child : semapore is unlocked now. the semaphore value is %d\n",val2);
+             
+             printf("Child finished !\n");
+     }
+     else
+     {
+     	     int flag = 1;
+     	     int val=0;	
+             do {
+                sleep(1);
+             	val = semctl ( semid , 0, GETVAL , semarg2 );
+             	printf("Parent: semaphore value is = %d\n",pval);
+             	if (pval == 1) {flag=0;printf("Parent : Semaphore is free\n");
+             } while (flag == 1);
+             printf("Parent is going to lock the semaphore\n");
+             sops->sem_op = -1;
+             semop ( semid , sops , 1 );
+             sharestr=(char *)shmat ( shmid , NULL , 0600 );
+             printf ( "%s\n" , sharestr );
+             shmdt ( sharestr );
+             printf("Parent is going to delete the semaphore\n");
+             shmctl ( shmid , IPC_RMID , 0 );
+     }
+}
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/1.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+void main ()							    
+{							    
+int pid	;						    
+							    
+if ( (pid = fork()) == 0 )				    
+	printf("1") ;					    
+else							    
+	printf("2") ;					    
+}		
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/10.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+
+void main()
+ {
+   int   pid,pid1,pid2,status;
+
+   if ((pid1=fork())==0)
+      printf("in child   1\n");
+   else
+      if ((pid2=fork())==0)
+            printf("in child 2\n");
+      else
+          {
+           pid=wait(&status);
+           pid=wait(&status);
+           if (pid==pid1)
+              printf("child 1 finished\n");
+           if (pid==pid2)
+              printf("child 2 finished\n");
+          }
+ }
+
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/11.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+
+void main()
+ {
+   int   pid_a,pid_b,pid1,pid2,status;
+
+   if ((pid1=fork())==0)
+      printf("in child   1\n");
+   else
+      if ((pid2=fork())==0)
+            printf("in child 2\n");
+      else
+          {
+           pid_a=wait(&status);
+             if (pid_a==pid1 )
+                 printf("child 1 finished\n");
+             if (pid_a==pid2 )
+                 printf("child 2 finished\n");
+           pid_b=wait(&status);
+             if (pid_b==pid1)
+                 printf("child 1 finished\n");
+             if (pid_b==pid2)
+                 printf("child 2 finished\n");
+          }
+ }
+
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/2.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+void main ()
+	{
+	int pid	;
+
+	if ( (pid = fork()) == 0 )
+		printf("1") ;
+	else
+		printf("2") ;
+	printf("3");
+	}
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/3.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+void      main ()
+        {
+        int pid , stat;
+
+
+	//fork returns 0 to son, son's pid to parent
+	pid = fork();
+        if ( pid == 0 ) //son
+                printf("fork returned zero. I am the son. my pid is %d parent's pid is %d\n", getpid(), getppid()) ;
+        else //parent
+          {
+		int result;
+                result = wait(&stat);
+                printf("I am the father. Fork returned %d, wait returned %d, stat is %d, my pid is %d", pid, result, stat, getpid()) ;
+          }
+        }
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/4.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* executable file fork4 does not exist */
+
+        void main ()
+        {
+        int pid , stat;
+
+        if ( (pid = fork()) == 0 )
+          {
+		int result;
+            result = execl("/u/grad/sasha/fork4","fork4",NULL);
+                printf("exec returned %d and errno is %d\n", result, errno) ;
+          }
+        else
+          {
+                wait(&stat);
+                printf("2") ;
+          }
+        }
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/5.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+      /* there is no program called fork5 */
+
+void        main ()
+        {
+        int pid , stat;
+
+        if ( (pid = fork()) == 0 )
+          {
+            execl("/u/grad/sasha/fork5","fork5",NULL);
+            printf("1") ;
+            exit(1);
+            }
+        else
+          {
+            wait(&stat);
+            printf("2") ;
+            if (stat != 0 )
+              printf("3");
+          }
+        }
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/6.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+/* there is a program called date */
+
+
+
+
+int  main ()
+{
+        int pid , stat;
+
+        if ( (pid = fork()) == 0 )
+        {
+            execl("/usr/bin/date","date",NULL);
+            printf("- 1(child) -\n") ;
+            exit(1);
+        }
+        else
+        {
+            wait(&stat);
+            printf("- 2(parent) -\n") ;
+            printf("- stat = <%d> -\n",stat) ;
+            if (stat != 0 )
+              printf("- 3(parent,child is failed) -\n");
+            else
+              printf("- 3(parent,child is succeeded) -\n");
+        }
+        return 0;
+}
+

שנה ב/סמסטר ב/מערכות הפעלה/תרגולים/תרגול 3 ו-4 - תהליכים_Processes - דוגמאות קוד/7.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+/* there is a program called stam (prints 4)*/
+int main()
+ {
+  int pid , stat;
+
+  if ( (pid = fork()) == 0 )
+  {
+     execl("./stam","stam",NULL);
+     printf("\n- 1 -\n") ;
+     exit(0);
+  }
+  else
+  {
+     wait(&stat);
+     printf("- 2 -\n") ;
+     if (stat != 0 )
+         printf("- 3 -\n");
+   }
+   return 0;
+ }
+