1 files changed, 39 insertions, 0 deletions
diff --git a/v_windows/v/vlib/crypto/rand/rand_linux.c.v b/v_windows/v/vlib/crypto/rand/rand_linux.c.v
new file mode 100644
index 0000000..52ff3da
--- /dev/null
+++ b/v_windows/v/vlib/crypto/rand/rand_linux.c.v
@@ -0,0 +1,39 @@
+// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module rand
+
+#include <sys/syscall.h>
+
+const (
+	read_batch_size = 256
+)
+
+// read returns an array of `bytes_needed` random bytes read from the OS.
+pub fn read(bytes_needed int) ?[]byte {
+	mut buffer := unsafe { malloc_noscan(bytes_needed) }
+	mut bytes_read := 0
+	mut remaining_bytes := bytes_needed
+	// getrandom syscall wont block if requesting <= 256 bytes
+	for bytes_read < bytes_needed {
+		batch_size := if remaining_bytes > rand.read_batch_size {
+			rand.read_batch_size
+		} else {
+			remaining_bytes
+		}
+		rbytes := unsafe { getrandom(batch_size, buffer + bytes_read) }
+		if rbytes == -1 {
+			unsafe { free(buffer) }
+			return IError(&ReadError{})
+		}
+		bytes_read += rbytes
+	}
+	return unsafe { buffer.vbytes(bytes_needed) }
+}
+
+fn getrandom(bytes_needed int, buffer voidptr) int {
+	if bytes_needed > rand.read_batch_size {
+		panic('getrandom() dont request more than $rand.read_batch_size bytes at once.')
+	}
+	return unsafe { C.syscall(C.SYS_getrandom, buffer, bytes_needed, 0) }
+}