fix bugs

Author: SchrodingerZhu

libc/src/sys/auxv/linux/getauxval.cpp

@@ -26,9 +26,12 @@
 #include "src/unistd/close.h"
 #include "src/unistd/read.h"
 
-// getauxval will work either with or without atexit support.
-// In order to detect if atexit is supported, we define a weak symbol.
-extern "C" [[gnu::weak]] int atexit(void (*)(void));
+// getauxval will work either with or without __cxa_atexit support.
+// In order to detect if __cxa_atexit is supported, we define a weak symbol.
+// We prefer __cxa_atexit as it is always defined as a C symbol whileas atexit
+// may not be created via objcopy yet.
+extern "C" [[gnu::weak]] int __cxa_atexit(void (*callback)(void *),
+ void *payload, void *);
 
 namespace LIBC_NAMESPACE {
 
@@ -49,19 +52,22 @@ static AuxEntry *auxv = nullptr;
 struct AuxvMMapGuard {
  constexpr static size_t AUXV_MMAP_SIZE = sizeof(AuxEntry) * MAX_AUXV_ENTRIES;
  void *ptr;
- AuxvMMapGuard(size_t size)
- : ptr(mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, -1, 0)) {}
+ AuxvMMapGuard()
+ : ptr(mmap(nullptr, AUXV_MMAP_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)) {}
  ~AuxvMMapGuard() {
  if (ptr != MAP_FAILED) {
  munmap(ptr, AUXV_MMAP_SIZE);
  }
  }
  void submit_to_global() {
  // atexit may fail, we do not set it to global in that case.
- int ret = atexit([]() {
- munmap(auxv, AUXV_MMAP_SIZE);
- auxv = nullptr;
- });
+ int ret = __cxa_atexit(
+ [](void *) {
+ munmap(auxv, AUXV_MMAP_SIZE);
+ auxv = nullptr;
+ },
+ nullptr, nullptr);
 
  if (ret != 0)
  return;
@@ -85,10 +91,10 @@ struct AuxvFdGuard {
 
 static void initialize_auxv_once(void) {
  // if we cannot get atexit, we cannot register the cleanup function.
- if (&atexit == nullptr)
+ if (&__cxa_atexit == nullptr)
  return;
 
- AuxvMMapGuard mmap_guard(AuxvMMapGuard::AUXV_MMAP_SIZE);
+ AuxvMMapGuard mmap_guard;
  if (!mmap_guard.allocated())
  return;
  auto *ptr = reinterpret_cast<AuxEntry *>(mmap_guard.ptr);

libc/test/src/sys/CMakeLists.txt

@@ -8,3 +8,4 @@ add_subdirectory(stat)
 add_subdirectory(utsname)
 add_subdirectory(wait)
 add_subdirectory(prctl)
+add_subdirectory(auxv)

libc/test/src/sys/auxv/CMakeLists.txt

@@ -0,0 +1,3 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+ add_subdirectory(${LIBC_TARGET_OS})
+endif()

libc/test/src/sys/auxv/linux/CMakeLists.txt

@@ -0,0 +1,14 @@
+add_custom_target(libc_sys_auxv_unittests)
+add_libc_unittest(
+ getauxval_test
+ SUITE
+ libc_sys_auxv_unittests
+ SRCS
+ getauxval_test.cpp
+ DEPENDS
+ libc.include.sys_auxv
+ libc.src.errno.errno
+ libc.src.sys.auxv.getauxval
+ libc.test.UnitTest.ErrnoSetterMatcher
+ libc.src.string.strstr
+)

libc/test/src/sys/auxv/linux/getauxval_test.cpp

@@ -0,0 +1,27 @@
+//===-- Unittests for getaxuval -------------------------------------------===//
+//
+// 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/auxv/getauxval.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+#include <src/string/strstr.h>
+#include <sys/auxv.h>
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+
+TEST(LlvmLibcGetauxvalTest, Basic) {
+ EXPECT_THAT(LIBC_NAMESPACE::getauxval(AT_PAGESZ), returns(GT(0ul)));
+ const char *filename;
+ auto getfilename = [&filename]() {
+ auto value = LIBC_NAMESPACE::getauxval(AT_EXECFN);
+ filename = reinterpret_cast<const char *>(value);
+ return value;
+ };
+ EXPECT_THAT(getfilename(), returns(NE(0ul)));
+ ASSERT_TRUE(LIBC_NAMESPACE::strstr(filename, "getauxval_test") != nullptr);
+}