pingpong finished

user/pingpong.c

@@ -0,0 +1,21 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char *argv[]) {
+  int proc_f2s[2], proc_s2f[2];
+  char buffer[8];
+  pipe(proc_f2s);
+  pipe(proc_s2f);
+
+  if (fork() == 0) {
+    read(proc_s2f[0], buffer, 4);
+    printf("%d: received %s\n", getpid(), buffer);
+    write(proc_f2s[1], "pong", strlen("pong"));
+  } else {
+    write(proc_s2f[1], "ping", strlen("ping"));
+    read(proc_f2s[0], buffer, 4);
+    printf("%d: received %s\n", getpid(), buffer);
+  }
+
+  exit(0);
+}