"debut TD0"

2019-2020/S3T_TP_06_IPC/Demonstrations/demo_sem.c

@@ -0,0 +1,75 @@
+///*****************************************************************/
+///* IUT NICE-COTE D'AZUR - Departement INFORMATIQUE - R. CHIGNOLI */
+///* Module DUT M311                               Theme IPC POSIX */
+///*****************************************************************/
+/// demo_sem.c : Demonstration d'utilisation d'un sémaphore
+/// usage : commande [-creation]  cle
+/// premier acces : utiliser l'option "-create"
+/// Depuis bash, utiliser la commande ls -l /dev/shm
+/// Depuis bash, utiliser la commande rm /dev/shm/*
+
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <semaphore.h>
+
+int main(int argc, char *argv[]) {
+    char reponse;
+    int mode, encore = 1;
+    sem_t *sem;
+
+    if (argc < 3) {
+        fprintf(stderr, "Usage: %s [ -create | -use ] nom_sem\n",
+                argv[0]);
+        exit(1);
+    }
+    if ((argc == 3) && (strcmp (argv[1], "-create") == 0)) {
+        mode =  O_RDWR | O_CREAT | O_EXCL;
+        printf ("\nMode creation\n\n");
+    } else if ((argc == 3) && (strcmp (argv[1], "-use") == 0)) {
+        mode = O_RDWR;
+        printf ("\nMode utilisation\n\n");
+    } else {
+        fprintf(stderr, "Usage: %s [ -create | -use ] nom\n", argv[0]);
+        exit(2);
+    }
+
+    sem = sem_open(argv[2], mode, 0600, 1);
+    if (sem == SEM_FAILED) {
+        perror ("open");
+        exit (3);
+    }
+    while (encore) {
+        printf("W,P,X,Q ? ");
+        reponse = getchar();
+        __fpurge(stdin); ///... pour bonne gestion du buffer clavier ...
+        switch (reponse) {
+        case 'P':
+            sem_wait (sem);
+            printf("... W OK.\n");
+            break;
+        case 'V':
+            sem_post (sem);
+            printf("... P OK.\n");
+            break;
+        case 'X':
+            sem_close (sem);
+            chdir ("/dev/shm");
+            sem_unlink (argv[2]);
+            printf("\n... Semaphore /dev/shm/sem.%s detruit\n", argv[2]);
+            encore = 0;
+            break;
+        case 'Q':
+            encore = 0;
+            break;
+        default:
+            printf("... Commande incorrecte\n");
+        }
+    }
+    printf("\n... Bye\n\n");
+}