[libc-commits] [libc] [libc] reland mincore (PR #79309)

[Schrodinger ZHU Yifan via libc-commits]

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@@ -0,0 +1,127 @@
+//===-- Unittests for mincore ---------------------------------------------===//
+//
+// 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/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/errno/libc_errno.h"
+#include "src/sys/mman/madvise.h"
+#include "src/sys/mman/mincore.h"
+#include "src/sys/mman/mmap.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"
+
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+TEST(LlvmLibcMincoreTest, UnMappedMemory) {
+  libc_errno = 0;
+  unsigned char vec;
+  int res = LIBC_NAMESPACE::mincore(nullptr, 1, &vec);
+  EXPECT_THAT(res, Fails(ENOMEM, -1));
+}
+
+TEST(LlvmLibcMincoreTest, UnalignedAddr) {
+  unsigned long page_size = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
+  void *addr = LIBC_NAMESPACE::mmap(nullptr, page_size, PROT_READ,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % page_size, 0ul);
+  libc_errno = 0;
+  int res = LIBC_NAMESPACE::mincore(static_cast<char *>(addr) + 1, 1, nullptr);
+  EXPECT_THAT(res, Fails(EINVAL, -1));
+  EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, page_size), Succeeds());
+}
+
+TEST(LlvmLibcMincoreTest, InvalidVec) {
+  unsigned long page_size = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
+  void *addr = LIBC_NAMESPACE::mmap(nullptr, 4 * page_size, PROT_READ,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % page_size, 0ul);
+  libc_errno = 0;
+  int res = LIBC_NAMESPACE::mincore(addr, 1, nullptr);
+  EXPECT_THAT(res, Fails(EFAULT, -1));
+  void *area = LIBC_NAMESPACE::mmap(nullptr, page_size, PROT_READ | PROT_WRITE,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(area, MAP_FAILED);
+  unsigned char *ptr = static_cast<unsigned char *>(area) + page_size - 3;
+  res = LIBC_NAMESPACE::mincore(addr, 4 * page_size, ptr);
+  EXPECT_THAT(res, Fails(EFAULT, -1));
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SchrodingerZhu wrote:

The invalid vector part seems extremely hard to test correctly. 

https://github.com/llvm/llvm-project/pull/79309