From c1d4f195bc63c7c591a540948f79d6156ab1c792 Mon Sep 17 00:00:00 2001
From: Kalesh Singh <kaleshsingh@google.com>
Date: Thu, 10 Aug 2023 13:46:09 -0700
Subject: [PATCH] protoutil: EncodedBuffer: Remove usage of PAGE_SIZE 4096

bionic hard codes the PAGE_SIZE macro as 4096. This is going away as
Android begins to support larger page sizes. Remove the usage of this
assumption from protoutil source; use instead getpagesize() which
provides the real pagesize.

Test: atest -c libprotoutil_test
Bug: 295228590
Change-Id: I6c3212600256d61a71430dfbbf7b0c9944fe4859
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
 libs/protoutil/src/EncodedBuffer.cpp        | 6 ++++--
 libs/protoutil/tests/EncodedBuffer_test.cpp | 9 ++++++---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/libs/protoutil/src/EncodedBuffer.cpp b/libs/protoutil/src/EncodedBuffer.cpp
index 96b54c63a836b..afb54a6c49b62 100644
--- a/libs/protoutil/src/EncodedBuffer.cpp
+++ b/libs/protoutil/src/EncodedBuffer.cpp
@@ -17,6 +17,7 @@
 
 #include <stdlib.h>
 #include <sys/mman.h>
+#include <unistd.h>
 
 #include <android/util/EncodedBuffer.h>
 #include <android/util/protobuf.h>
@@ -25,7 +26,8 @@
 namespace android {
 namespace util {
 
-const size_t BUFFER_SIZE = 8 * 1024; // 8 KB
+constexpr size_t BUFFER_SIZE = 8 * 1024; // 8 KB
+const size_t kPageSize = getpagesize();
 
 EncodedBuffer::Pointer::Pointer() : Pointer(BUFFER_SIZE)
 {
@@ -92,7 +94,7 @@ EncodedBuffer::EncodedBuffer(size_t chunkSize)
 {
     // Align chunkSize to memory page size
     chunkSize = chunkSize == 0 ? BUFFER_SIZE : chunkSize;
-    mChunkSize = (chunkSize / PAGE_SIZE + ((chunkSize % PAGE_SIZE == 0) ? 0 : 1)) * PAGE_SIZE;
+    mChunkSize = (chunkSize + (kPageSize - 1)) & ~(kPageSize - 1);
     mWp = Pointer(mChunkSize);
     mEp = Pointer(mChunkSize);
 }
diff --git a/libs/protoutil/tests/EncodedBuffer_test.cpp b/libs/protoutil/tests/EncodedBuffer_test.cpp
index 8a7becf68d693..a09558544c268 100644
--- a/libs/protoutil/tests/EncodedBuffer_test.cpp
+++ b/libs/protoutil/tests/EncodedBuffer_test.cpp
@@ -15,13 +15,16 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+#include <unistd.h>
+
 using namespace android::util;
 using android::sp;
 
 constexpr size_t __TEST_CHUNK_SIZE = 16UL;
-constexpr size_t TEST_CHUNK_SIZE = (__TEST_CHUNK_SIZE + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
-constexpr size_t TEST_CHUNK_HALF_SIZE = TEST_CHUNK_SIZE / 2;
-constexpr size_t TEST_CHUNK_3X_SIZE = 3 * TEST_CHUNK_SIZE;
+const size_t kPageSize = getpagesize();
+const size_t TEST_CHUNK_SIZE = (__TEST_CHUNK_SIZE + (kPageSize - 1)) & ~(kPageSize - 1);
+const size_t TEST_CHUNK_HALF_SIZE = TEST_CHUNK_SIZE / 2;
+const size_t TEST_CHUNK_3X_SIZE = 3 * TEST_CHUNK_SIZE;
 
 static void expectPointer(EncodedBuffer::Pointer* p, size_t pos) {
     EXPECT_EQ(p->pos(), pos);