4 files changed, 82 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..783cf17
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+entropyd
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..ddc3c0f
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module entropyd
+
+go 1.16
+
+require golang.org/x/sys v0.0.0-20210415045647-66c3f260301c
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..0c07c25
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/sys v0.0.0-20210415045647-66c3f260301c h1:6L+uOeS3OQt/f4eFHXZcTxeZrGCuz+CLElgEBjbcTA4=
+golang.org/x/sys v0.0.0-20210415045647-66c3f260301c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..be05e28
--- /dev/null
+++ b/main.go
@@ -0,0 +1,74 @@
+package main
+
+import (
+	"fmt"
+	"golang.org/x/sys/unix"
+	"log"
+	"math/rand"
+	"os"
+	"time"
+	"unsafe"
+)
+
+const BUFSIZE = 512
+
+type rand_pool_info struct {
+	entropy_count int
+	buf_size      int
+	buf           [512]byte
+}
+
+var pid int
+
+func init() {
+	log.SetFlags(0)
+	pid = os.Getpid()
+}
+
+func ioctl(fd int, req uint, ptr unsafe.Pointer) error {
+	_, _, errno := unix.Syscall(unix.SYS_IOCTL,
+		uintptr(fd),
+		uintptr(req),
+		uintptr(ptr))
+
+	if errno != 0 {
+		return fmt.Errorf("ioctl: %w", errno)
+	}
+
+	return nil
+}
+
+func feed(fd int) error {
+	seed := pid * time.Now().Nanosecond()
+	rand.Seed(int64(seed))
+
+	output := &rand_pool_info{
+		entropy_count: BUFSIZE * 8,
+		buf_size:      BUFSIZE,
+	}
+
+	rand.Read(output.buf[:])
+
+	err := ioctl(fd, unix.RNDADDENTROPY, unsafe.Pointer(output))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func main() {
+	fd, err := unix.Open("/dev/random", unix.O_RDWR, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer unix.Close(fd)
+
+	for {
+		if err := feed(fd); err != nil {
+			log.Fatalf("feed failed: %s", err)
+		}
+
+		time.Sleep(time.Second)
+	}
+}