code review 4342043: crypto/rand: Fix on Plan 9

src/pkg/crypto/rand/rand_plan9.go

Index: src/pkg/crypto/rand/rand_plan9.go 
=================================================================== 
new file mode 100644 
--- /dev/null 
+++ b/src/pkg/crypto/rand/rand_plan9.go 
@@ -0,0 +1,33 @@ 
+// Copyright 2010 The Go Authors. All rights reserved. 
+// Use of this source code is governed by a BSD-style 
+// license that can be found in the LICENSE file. 
+ 
+package rand 
+ 
+import ( 
+	"io" 
+	"os" 
+	"sync" 
+) 
+ 
+func init() { Reader = newReader(nil) } 
+ 
+// A devReader satisfies reads by reading the file named name. 
+type devReader struct { 
+	name string 
+	f io.Reader 
+	mu sync.Mutex 
+} 
+ 
+func (r *devReader) Read(b []byte) (n int, err os.Error) { 
+	r.mu.Lock() 
+	defer r.mu.Unlock() 
+	if r.f == nil { 
+	f, err := os.Open(r.name) 
+	if f == nil { 
+	return 0, err 
+	} 
+	r.f = f 
+	} 
+	return r.f.Read(b) 
+}