libbinder: separate OS-specific code from Utils.cpp

Separate the OS-specific functions setNonBlocking and
getRandomBytes from Utils.cpp into a separate OS-specific
OS.cpp file that other operating systems can override at
build time.

Bug: 224644083
Test: build Trusty
Change-Id: I2703fb81d4370b5f6264556ae57fdddb0573971a
diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index 3d515b5..25754e8 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -88,6 +88,7 @@
         "IInterface.cpp",
         "IResultReceiver.cpp",
         "IShellCallback.cpp",
+        "OS.cpp",
         "Parcel.cpp",
         "ParcelFileDescriptor.cpp",
         "RpcSession.cpp",
diff --git a/libs/binder/OS.cpp b/libs/binder/OS.cpp
new file mode 100644
index 0000000..6eb7272
--- /dev/null
+++ b/libs/binder/OS.cpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "OS.h"
+
+#include <android-base/file.h>
+#include <string.h>
+
+using android::base::ErrnoError;
+using android::base::Result;
+
+namespace android {
+
+Result<void> setNonBlocking(android::base::borrowed_fd fd) {
+    int flags = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_GETFL));
+    if (flags == -1) {
+        return ErrnoError() << "Could not get flags for fd";
+    }
+    if (int ret = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_SETFL, flags | O_NONBLOCK)); ret == -1) {
+        return ErrnoError() << "Could not set non-blocking flag for fd";
+    }
+    return {};
+}
+
+status_t getRandomBytes(uint8_t* data, size_t size) {
+    int ret = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
+    if (ret == -1) {
+        return -errno;
+    }
+
+    base::unique_fd fd(ret);
+    if (!base::ReadFully(fd, data, size)) {
+        return -errno;
+    }
+    return OK;
+}
+
+} // namespace android
diff --git a/libs/binder/OS.h b/libs/binder/OS.h
new file mode 100644
index 0000000..e802e9c
--- /dev/null
+++ b/libs/binder/OS.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <stddef.h>
+#include <cstdint>
+
+#include <android-base/result.h>
+#include <android-base/unique_fd.h>
+#include <utils/Errors.h>
+
+namespace android {
+
+android::base::Result<void> setNonBlocking(android::base::borrowed_fd fd);
+
+status_t getRandomBytes(uint8_t* data, size_t size);
+
+} // namespace android
diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 1cd1fd3..ee90710 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -34,6 +34,7 @@
 
 #include "BuildFlags.h"
 #include "FdTrigger.h"
+#include "OS.h"
 #include "RpcSocketAddress.h"
 #include "RpcState.h"
 #include "RpcWireFormat.h"
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index 2d9c933..80f6a37 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -37,6 +37,7 @@
 #include <utils/String8.h>
 
 #include "FdTrigger.h"
+#include "OS.h"
 #include "RpcSocketAddress.h"
 #include "RpcState.h"
 #include "RpcWireFormat.h"
diff --git a/libs/binder/Utils.cpp b/libs/binder/Utils.cpp
index b0289a7..0314b0f 100644
--- a/libs/binder/Utils.cpp
+++ b/libs/binder/Utils.cpp
@@ -16,40 +16,12 @@
 
 #include "Utils.h"
 
-#include <android-base/file.h>
 #include <string.h>
 
-using android::base::ErrnoError;
-using android::base::Result;
-
 namespace android {
 
 void zeroMemory(uint8_t* data, size_t size) {
     memset(data, 0, size);
 }
 
-Result<void> setNonBlocking(android::base::borrowed_fd fd) {
-    int flags = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_GETFL));
-    if (flags == -1) {
-        return ErrnoError() << "Could not get flags for fd";
-    }
-    if (int ret = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_SETFL, flags | O_NONBLOCK)); ret == -1) {
-        return ErrnoError() << "Could not set non-blocking flag for fd";
-    }
-    return {};
-}
-
-status_t getRandomBytes(uint8_t* data, size_t size) {
-    int ret = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
-    if (ret == -1) {
-        return -errno;
-    }
-
-    base::unique_fd fd(ret);
-    if (!base::ReadFully(fd, data, size)) {
-        return -errno;
-    }
-    return OK;
-}
-
 } // namespace android
diff --git a/libs/binder/Utils.h b/libs/binder/Utils.h
index 37c1262..7c6d6f1 100644
--- a/libs/binder/Utils.h
+++ b/libs/binder/Utils.h
@@ -15,11 +15,10 @@
  */
 
 #include <stddef.h>
+#include <sys/uio.h>
 #include <cstdint>
 #include <optional>
 
-#include <android-base/result.h>
-#include <android-base/unique_fd.h>
 #include <log/log.h>
 #include <utils/Errors.h>
 
@@ -36,10 +35,6 @@
 // avoid optimizations
 void zeroMemory(uint8_t* data, size_t size);
 
-android::base::Result<void> setNonBlocking(android::base::borrowed_fd fd);
-
-status_t getRandomBytes(uint8_t* data, size_t size);
-
 // View of contiguous sequence. Similar to std::span.
 template <typename T>
 struct Span {