[libc-commits] [libc] [libc][mman] implement msync (PR #84700)

[via libc-commits]

================
@@ -0,0 +1,69 @@
+//===-- Unittests for msync -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/errno/libc_errno.h"
+#include "src/sys/mman/mlock.h"
+#include "src/sys/mman/mmap.h"
+#include "src/sys/mman/msync.h"
+#include "src/sys/mman/munlock.h"
+#include "src/sys/mman/munmap.h"
+#include "src/unistd/sysconf.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/LibcTest.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+
+struct PageHolder {
+  size_t size;
+  void *addr;
+
+  PageHolder()
+      : size(LIBC_NAMESPACE::sysconf(_SC_PAGESIZE)),
+        addr(LIBC_NAMESPACE::mmap(nullptr, size, PROT_READ | PROT_WRITE,
+                                  MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)) {}
+  ~PageHolder() {
+    if (addr != MAP_FAILED)
+      LIBC_NAMESPACE::munmap(addr, size);
+  }
+
+  char &operator[](size_t i) { return reinterpret_cast<char *>(addr)[i]; }
+
+  bool is_valid() { return addr != MAP_FAILED; }
+};
+
+TEST(LlvmLibcMsyncTest, UnMappedMemory) {
+  EXPECT_THAT(LIBC_NAMESPACE::msync(nullptr, 1024, MS_SYNC), Fails(ENOMEM));
+  EXPECT_THAT(LIBC_NAMESPACE::msync(nullptr, 1024, MS_ASYNC), Fails(ENOMEM));
+}
+
+TEST(LlvmLibcMsyncTest, LockedPage) {
+  PageHolder page;
+  EXPECT_TRUE(page.is_valid());
+  EXPECT_THAT(LIBC_NAMESPACE::mlock(page.addr, page.size), Succeeds());
+  EXPECT_THAT(
+      LIBC_NAMESPACE::msync(page.addr, page.size, MS_SYNC | MS_INVALIDATE),
+      Fails(EBUSY));
+  EXPECT_THAT(LIBC_NAMESPACE::munlock(page.addr, page.size), Succeeds());
+  EXPECT_THAT(LIBC_NAMESPACE::msync(page.addr, page.size, MS_SYNC), Succeeds());
+}
+
+TEST(LlvmLibcMsyncTest, UnalignedAddress) {
+  PageHolder page;
+  EXPECT_TRUE(page.is_valid());
----------------
lntue wrote:

Use `ASSERT_TRUE` to verify the precondtion.

https://github.com/llvm/llvm-project/pull/84700