certificate: Replace platform bridge with CGO JNI

common/certificate/system_android.go

@@ -0,0 +1,34 @@
+//go:build android
+
+package certificate
+
+/*
+#include <stdint.h>
+#include <stdlib.h>
+extern void *box_system_certificates_der(uintptr_t vm, int *out_length);
+*/
+import "C"
+
+import (
+	"crypto/x509"
+
+	"github.com/sagernet/sing-box/common/jni"
+)
+
+func systemCertificates() []*x509.Certificate {
+	vm := jni.VM()
+	if vm == 0 {
+		return nil
+	}
+	var length C.int
+	pointer := C.box_system_certificates_der(C.uintptr_t(vm), &length)
+	if pointer == nil {
+		return nil
+	}
+	defer C.free(pointer)
+	certificates, err := x509.ParseCertificates(C.GoBytes(pointer, length))
+	if err != nil {
+		return nil
+	}
+	return certificates
+}