Small tweaks
Lots of new code imported.
diff --git a/src/lib9p/uid.c b/src/lib9p/uid.c
new file mode 100644
index 0000000..84b98bd
--- /dev/null
+++ b/src/lib9p/uid.c
@@ -0,0 +1,34 @@
+#include <u.h>
+#include <libc.h>
+#include <auth.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+
+/*
+ * simplistic permission checking. assume that
+ * each user is the leader of her own group.
+ */
+int
+hasperm(File *f, char *uid, int p)
+{
+ int m;
+
+ m = f->dir.mode & 7; /* other */
+ if((p & m) == p)
+ return 1;
+
+ if(strcmp(f->dir.uid, uid) == 0) {
+ m |= (f->dir.mode>>6) & 7;
+ if((p & m) == p)
+ return 1;
+ }
+
+ if(strcmp(f->dir.gid, uid) == 0) {
+ m |= (f->dir.mode>>3) & 7;
+ if((p & m) == p)
+ return 1;
+ }
+
+ return 0;
+}
