1 files changed, 61 insertions, 0 deletions
diff --git a/sync/sync.c b/sync/sync.c
new file mode 100644
index 0000000..e1fbc4c
--- /dev/null
+++ b/sync/sync.c
@@ -0,0 +1,61 @@
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+
+int main(argc, argv)
+int argc;
+char **argv;
+{
+	int shmid, i, pid, n_read, n_write;
+	char *mem, **arg_r, **arg_w;
+
+	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);
+	}
+
+	for (i = 0; i < 1<<14; i++) {
+		*(mem + i) = 0x30;
+	}
+
+	arg_r = malloc(sizeof(char*) * 2);
+	arg_w = malloc(sizeof(char*) * 2);
+
+	*(arg_r + 1) = NULL;
+	*(arg_w + 1) = NULL;
+
+	for (i = 0; i < n_read; i++){
+		sprintf(*arg_r, "%d", i);
+		if (pid = fork()) {
+			printf("starting reader %d...\n", i);
+		} else {
+			execvp("./reader", arg_r);
+		}
+	}
+
+	for (i = 0; i < n_write; i++) {
+		sprintf(*arg_w, "%d", i);
+		if (pid = fork()) {
+			printf("starting writer %d...\n", i);
+		} else {
+			execvp("./writer", arg_w);
+		}
+		
+	}
+}