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