implement write

1 files changed, 20 insertions, 2 deletions

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 3a780c6..2116e5c 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -114,8 +114,26 @@ read (int fd_i, void *buf, unsigned size)
 static int
 write (int fd_i, const void *buf, unsigned size)
 {
-  printf ("write: %s", (char *)buf);
-  return 0;
+  struct thread *thread = thread_current ();
+
+  if (fd_i == 1) {
+    // stdout
+    putbuf ((const char *)buf, size);
+    return size;
+  } else if (fd_i == 0) {
+    printf ("[%s] write: tried to write to stdin\n", thread->name);
+    return -1;
+  }
+
+  struct file *file = get_file (thread, fd_i);
+  if (!file) {
+    return -1;
+  }
+
+  int n = file_write(file, buf, size);
+  printf ("%d/%d: %s\n", n, size, (char *)buf);
+
+  return n;
 }
 
 static void