1 files changed, 118 insertions, 0 deletions
diff --git a/CS3871/sync/sync.c b/CS3871/sync/sync.c
new file mode 100644
index 0000000..23d6ba1
--- /dev/null
+++ b/CS3871/sync/sync.c
@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define NSEM 3
+
+union semun {
+	int val;
+	struct semid_ds *buf;
+	ushort *array;
+};
+
+
+int shmid, semid;
+
+void quit(signum)
+int signum;
+{
+	shmctl(shmid, IPC_RMID, NULL);
+	semctl(semid, IPC_RMID, 0);
+}
+
+
+int main(argc, argv)
+int argc;
+char **argv;
+{
+	int i, pid, n_read, n_write, w;
+	char *mem, **arg_r, **arg_w;
+	union semun semarg;
+
+	if (argc < 2) {
+		printf("usage: sync [number readers] [number writers]\n");
+		exit(1);
+	}
+	n_read = atoi(argv[1]);
+	n_write = atoi(argv[2]);
+
+	if ((shmid = shmget(52, 1<<14, IPC_CREAT | 0666)) == -1){
+		perror("shmget: shmget failed");
+		exit(1);
+	}
+
+	if ((mem = shmat(shmid, NULL, 0)) == (char *) -1) {
+		perror("shmat");
+		exit(1);
+	}
+printf("Sshmid: %x\n", shmid);
+	signal(SIGQUIT, quit);
+
+	for (i = 0; i < 1<<14; i++) {
+		*(mem + i) = 0x30;
+	}
+
+	if ((semid = semget(shmid, NSEM, 0666 | IPC_CREAT)) == -1) {
+		perror("Ssemget: ");
+		exit(1);
+	}
+
+	semarg.val = 1;
+	for (i = 0; i < NSEM; i++) {
+		if ((semctl(semid, i, SETVAL, semarg)) == -1) {
+			perror("semctl: ");
+			exit(1);
+		}
+	}
+
+
+	arg_r = malloc(sizeof(char*) * 3);
+	arg_w = malloc(sizeof(char*) * 3);
+	*arg_r = malloc(sizeof(char) * 10);
+	*arg_w = malloc(sizeof(char) * 10);
+
+	*(arg_r + 1) = malloc(sizeof(char) * 50);
+	*(arg_w + 1) = malloc(sizeof(char) * 50);
+
+	*arg_r = "reader";
+	*arg_w = "writer";
+
+	*(arg_r + 2) = NULL;
+	*(arg_w + 2) = NULL;
+
+	for (i = 0; i < n_read; i++){
+		sprintf(*(arg_r + 1), "%d", i);
+		if (pid = fork()) {
+			/* printf("starting reader %d...\n", i); */
+		} else {
+			int ret = execv("./reader", arg_r);
+			printf("exec retern %d", ret);
+		}
+	}
+
+	for (i = 0; i < n_write; i++) {
+		sprintf(*(arg_w + 1), "%d", i);
+		if (pid = fork()) {
+			/* printf("starting writer %d...\n", i); */
+		} else {
+			execvp("./writer", arg_w);
+		}
+		
+	}
+
+	shmdt(mem);
+printf("sync done...\n");
+/* TODO
+ * why is this returning 8
+ */
+	for (i = 0; i < (n_write + n_read); i++) {
+		wait(&w);
+		printf("\nReturned with code:%d\n", WEXITSTATUS(w));
+	}
+	quit();
+}