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- a0673e81da7ee7e322283e518331a4cdaeca837b Internal change by Abseil Team <absl-team@google.com>

Browse source 
- 537e863510a423968c2d319263dd1c100695a2e9 Add internal-only functionality to examine the stack, to ... by Derek Mauro <dmauro@google.com>
  - 1ded12406d8b8fd7be910c8dfe8c2a8edf66136e Explicitly suppress the default move constructor and assi... by Derek Mauro <dmauro@google.com>
  - 347d38447ebc38e5d33fec6b67988880eb3cd249 Move implementation detail do_mmap64 to a new file. by Greg Falcon <gfalcon@google.com>

GitOrigin-RevId: a0673e81da7ee7e322283e518331a4cdaeca837b
Change-Id: I5a347d34d5173082b3a78eb53432481b32c94b69
This commit is contained in:
Abseil Team 2018-04-11 09:52:42 -07:00 • committed by Matt Calabrese
parent 475d64f2de
commit a7e522daf1
5 changed files with 186 additions and 88 deletions
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1
absl/base/BUILD.bazel
View file

@ -104,6 +104,7 @@ cc_library(
"internal/malloc_hook_mmap_linux.inc",
],
hdrs = [
"internal/direct_mmap.h",
"internal/low_level_alloc.h",
"internal/malloc_hook.h",
"internal/malloc_hook_c.h",

1
absl/base/CMakeLists.txt
View file

@ -32,6 +32,7 @@ list(APPEND BASE_PUBLIC_HEADERS
list(APPEND BASE_INTERNAL_HEADERS
"internal/atomic_hook.h"
"internal/cycleclock.h"
"internal/direct_mmap.h"
"internal/endian.h"
"internal/exception_testing.h"
"internal/exception_safety_testing.h"

145
absl/base/internal/direct_mmap.h Normal file
View file

@ -0,0 +1,145 @@
// Copyright 2017 The Abseil Authors.
//
// 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.
//
// Functions for directly invoking mmap() via syscall, avoiding the case where
// mmap() has been locally overridden.
#ifndef ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#define ABSL_BASE_INTERNAL_DIRECT_MMAP_H_
#include "absl/base/config.h"
#if ABSL_HAVE_MMAP
#include <sys/mman.h>
#ifdef __linux__
#include <sys/types.h>
#ifdef __BIONIC__
#include <sys/syscall.h>
#else
#include <syscall.h>
#endif
#include <linux/unistd.h>
#include <unistd.h>
#include <cerrno>
#include <cstdarg>
#include <cstdint>
#ifdef __mips__
// Include definitions of the ABI currently in use.
#ifdef __BIONIC__
// Android doesn't have sgidefs.h, but does have asm/sgidefs.h, which has the
// definitions we need.
#include <asm/sgidefs.h>
#else
#include <sgidefs.h>
#endif // __BIONIC__
#endif // __mips__
// SYS_mmap and SYS_munmap are not defined in Android.
#ifdef __BIONIC__
extern "C" void* __mmap2(void*, size_t, int, int, int, long);
#if defined(__NR_mmap) && !defined(SYS_mmap)
#define SYS_mmap __NR_mmap
#endif
#ifndef SYS_munmap
#define SYS_munmap __NR_munmap
#endif
#endif // __BIONIC__
namespace absl {
namespace base_internal {
// Platform specific logic extracted from
// https://chromium.googlesource.com/linux-syscall-support/+/master/linux_syscall_support.h
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off64_t offset) __THROW {
#if defined(__i386__) || defined(__ARM_ARCH_3__) || defined(__ARM_EABI__) || \
(defined(__mips__) && _MIPS_SIM == _MIPS_SIM_ABI32) || \
(defined(__PPC__) && !defined(__PPC64__)) || \
(defined(__s390__) && !defined(__s390x__))
// On these architectures, implement mmap with mmap2.
static int pagesize = 0;
if (pagesize == 0) {
pagesize = getpagesize();
}
if (offset < 0 || offset % pagesize != 0) {
errno = EINVAL;
return MAP_FAILED;
}
#ifdef __BIONIC__
// SYS_mmap2 has problems on Android API level <= 16.
// Workaround by invoking __mmap2() instead.
return __mmap2(start, length, prot, flags, fd, offset / pagesize);
#else
return reinterpret_cast<void*>(
syscall(SYS_mmap2, start, length, prot, flags, fd,
static_cast<off_t>(offset / pagesize)));
#endif
#elif defined(__s390x__)
// On s390x, mmap() arguments are passed in memory.
uint32_t buf[6] = {
reinterpret_cast<uint32_t>(start), static_cast<uint32_t>(length),
static_cast<uint32_t>(prot), static_cast<uint32_t>(flags),
static_cast<uint32_t>(fd), static_cast<uint32_t>(offset)};
return reintrepret_cast<void*>(syscall(SYS_mmap, buf));
#elif defined(__x86_64__)
// The x32 ABI has 32 bit longs, but the syscall interface is 64 bit.
// We need to explicitly cast to an unsigned 64 bit type to avoid implicit
// sign extension. We can't cast pointers directly because those are
// 32 bits, and gcc will dump ugly warnings about casting from a pointer
// to an integer of a different size. We also need to make sure __off64_t
// isn't truncated to 32-bits under x32.
#define MMAP_SYSCALL_ARG(x) ((uint64_t)(uintptr_t)(x))
return reinterpret_cast<void*>(
syscall(SYS_mmap, MMAP_SYSCALL_ARG(start), MMAP_SYSCALL_ARG(length),
MMAP_SYSCALL_ARG(prot), MMAP_SYSCALL_ARG(flags),
MMAP_SYSCALL_ARG(fd), static_cast<uint64_t>(offset)));
#undef MMAP_SYSCALL_ARG
#else // Remaining 64-bit aritectures.
static_assert(sizeof(unsigned long) == 8, "Platform is not 64-bit");
return reinterpret_cast<void*>(
syscall(SYS_mmap, start, length, prot, flags, fd, offset));
#endif
}
inline int DirectMunmap(void* start, size_t length) {
return static_cast<int>(syscall(SYS_munmap, start, length));
}
} // namespace base_internal
} // namespace absl
#else // !__linux__
// For non-linux platforms where we have mmap, just dispatch directly to the
// actual mmap()/munmap() methods.
inline void* DirectMmap(void* start, size_t length, int prot, int flags, int fd,
off_t offset) {
return mmap(start, length, prot, flags, fd, offset);
}
inline int DirectMunmap(void* start, size_t length) {
return munmap(start, length);
}
#endif // __linux__
#endif // ABSL_HAVE_MMAP
#endif // ABSL_BASE_INTERNAL_DIRECT_MMAP_H_

94
absl/base/internal/malloc_hook_mmap_linux.inc
View file

@ -35,89 +35,18 @@
#include <cstdarg>
#include <cstdint>
#ifdef __mips__
// Include definitions of the ABI currently in use.
#ifdef __BIONIC__
// Android doesn't have sgidefs.h, but does have asm/sgidefs.h, which has the
// definitions we need.
#include <asm/sgidefs.h>
#else
#include <sgidefs.h>
#endif // __BIONIC__
#endif // __mips__
#include "absl/base/internal/direct_mmap.h"
// SYS_mmap, SYS_munmap, and SYS_mremap are not defined in Android.
// SYS_mremap is not defined in Android.
#ifdef __BIONIC__
extern "C" void *__mmap2(void *, size_t, int, int, int, long);
#if defined(__NR_mmap) && !defined(SYS_mmap)
#define SYS_mmap __NR_mmap
#endif
#ifndef SYS_munmap
#define SYS_munmap __NR_munmap
#endif
#ifndef SYS_mremap
#define SYS_mremap __NR_mremap
#endif
#endif // __BIONIC__
// Platform specific logic extracted from
// https://chromium.googlesource.com/linux-syscall-support/+/master/linux_syscall_support.h
static inline void* do_mmap64(void* start, size_t length, int prot,
int flags, int fd, off64_t offset) __THROW {
#if defined(__i386__) || \
defined(__ARM_ARCH_3__) || defined(__ARM_EABI__) || \
(defined(__mips__) && _MIPS_SIM == _MIPS_SIM_ABI32) || \
(defined(__PPC__) && !defined(__PPC64__)) || \
(defined(__s390__) && !defined(__s390x__))
// On these architectures, implement mmap with mmap2.
static int pagesize = 0;
if (pagesize == 0) {
pagesize = getpagesize();
}
if (offset < 0 || offset % pagesize != 0) {
errno = EINVAL;
return MAP_FAILED;
}
#ifdef __BIONIC__
// SYS_mmap2 has problems on Android API level <= 16.
// Workaround by invoking __mmap2() instead.
return __mmap2(start, length, prot, flags, fd, offset / pagesize);
#else
return reinterpret_cast<void*>(
syscall(SYS_mmap2, start, length, prot, flags, fd,
static_cast<off_t>(offset / pagesize)));
#endif
#elif defined(__s390x__)
// On s390x, mmap() arguments are passed in memory.
uint32_t buf[6] = {
reinterpret_cast<uint32_t>(start), static_cast<uint32_t>(length),
static_cast<uint32_t>(prot), static_cast<uint32_t>(flags),
static_cast<uint32_t>(fd), static_cast<uint32_t>(offset)};
return reintrepret_cast<void*>(syscall(SYS_mmap, buf));
#elif defined(__x86_64__)
// The x32 ABI has 32 bit longs, but the syscall interface is 64 bit.
// We need to explicitly cast to an unsigned 64 bit type to avoid implicit
// sign extension. We can't cast pointers directly because those are
// 32 bits, and gcc will dump ugly warnings about casting from a pointer
// to an integer of a different size. We also need to make sure __off64_t
// isn't truncated to 32-bits under x32.
#define MMAP_SYSCALL_ARG(x) ((uint64_t)(uintptr_t)(x))
return reinterpret_cast<void*>(
syscall(SYS_mmap, MMAP_SYSCALL_ARG(start), MMAP_SYSCALL_ARG(length),
MMAP_SYSCALL_ARG(prot), MMAP_SYSCALL_ARG(flags),
MMAP_SYSCALL_ARG(fd), static_cast<uint64_t>(offset)));
#undef MMAP_SYSCALL_ARG
#else // Remaining 64-bit aritectures.
static_assert(sizeof(unsigned long) == 8, "Platform is not 64-bit");
return reinterpret_cast<void*>(
syscall(SYS_mmap, start, length, prot, flags, fd, offset));
#endif
}
// We use do_mmap64 abstraction to put MallocHook::InvokeMmapHook
// calls right into mmap and mmap64, so that the stack frames in the caller's
// stack are at the same offsets for all the calls of memory allocating
// functions.
// We put MallocHook::InvokeMmapHook calls right into mmap and mmap64, so that
// the stack frames in the caller's stack are at the same offsets for all the
// calls of memory allocating functions.
// Put all callers of MallocHook::Invoke* in this module into
// malloc_hook section,
@ -148,7 +77,8 @@ extern "C" void* mmap64(void *start, size_t length, int prot, int flags,
void *result;
if (!absl::base_internal::MallocHook::InvokeMmapReplacement(
start, length, prot, flags, fd, offset, &result)) {
result = do_mmap64(start, length, prot, flags, fd, offset);
result = absl::base_internal::DirectMmap(start, length, prot, flags, fd,
offset);
}
absl::base_internal::MallocHook::InvokeMmapHook(result, start, length, prot,
flags, fd, offset);
@ -164,7 +94,8 @@ extern "C" void* mmap(void *start, size_t length, int prot, int flags,
void *result;
if (!absl::base_internal::MallocHook::InvokeMmapReplacement(
start, length, prot, flags, fd, offset, &result)) {
result = do_mmap64(start, length, prot, flags, fd,
result = absl::base_internal::DirectMmap(
start, length, prot, flags, fd,
static_cast<size_t>(offset)); // avoid sign extension
}
absl::base_internal::MallocHook::InvokeMmapHook(result, start, length, prot,
@ -179,7 +110,7 @@ extern "C" int munmap(void* start, size_t length) __THROW {
int result;
if (!absl::base_internal::MallocHook::InvokeMunmapReplacement(start, length,
&result)) {
result = syscall(SYS_munmap, start, length);
result = absl::base_internal::DirectMunmap(start, length);
}
return result;
}
@ -219,7 +150,8 @@ namespace base_internal {
void* result;
if (!MallocHook::InvokeMmapReplacement(
start, length, prot, flags, fd, offset, &result)) {
result = do_mmap64(start, length, prot, flags, fd, offset);
result = absl::base_internal::DirectMmap(start, length, prot, flags, fd,
offset);
}
return result;
}
@ -227,7 +159,7 @@ namespace base_internal {
/*static*/int MallocHook::UnhookedMUnmap(void *start, size_t length) {
int result;
if (!MallocHook::InvokeMunmapReplacement(start, length, &result)) {
result = syscall(SYS_munmap, start, length);
result = absl::base_internal::DirectMunmap(start, length);
}
return result;
}

31
absl/synchronization/mutex.h
View file

@ -519,11 +519,16 @@ class SCOPED_LOCKABLE MutexLock {
explicit MutexLock(Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) {
this->mu_->Lock();
}
MutexLock(const MutexLock &) = delete; // NOLINT(runtime/mutex)
MutexLock(MutexLock&&) = delete; // NOLINT(runtime/mutex)
MutexLock& operator=(const MutexLock&) = delete;
MutexLock& operator=(MutexLock&&) = delete;
~MutexLock() UNLOCK_FUNCTION() { this->mu_->Unlock(); }
private:
Mutex *const mu_;
MutexLock(const MutexLock &) = delete; // NOLINT(runtime/mutex)
MutexLock& operator=(const MutexLock&) = delete;
};
// ReaderMutexLock
@ -536,13 +541,18 @@ class SCOPED_LOCKABLE ReaderMutexLock {
: mu_(mu) {
mu->ReaderLock();
}
ReaderMutexLock(const ReaderMutexLock&) = delete;
ReaderMutexLock(ReaderMutexLock&&) = delete;
ReaderMutexLock& operator=(const ReaderMutexLock&) = delete;
ReaderMutexLock& operator=(ReaderMutexLock&&) = delete;
~ReaderMutexLock() UNLOCK_FUNCTION() {
this->mu_->ReaderUnlock();
}
private:
Mutex *const mu_;
ReaderMutexLock(const ReaderMutexLock&) = delete;
ReaderMutexLock& operator=(const ReaderMutexLock&) = delete;
};
// WriterMutexLock
@ -555,13 +565,18 @@ class SCOPED_LOCKABLE WriterMutexLock {
: mu_(mu) {
mu->WriterLock();
}
WriterMutexLock(const WriterMutexLock&) = delete;
WriterMutexLock(WriterMutexLock&&) = delete;
WriterMutexLock& operator=(const WriterMutexLock&) = delete;
WriterMutexLock& operator=(WriterMutexLock&&) = delete;
~WriterMutexLock() UNLOCK_FUNCTION() {
this->mu_->WriterUnlock();
}
private:
Mutex *const mu_;
WriterMutexLock(const WriterMutexLock&) = delete;
WriterMutexLock& operator=(const WriterMutexLock&) = delete;
};
// -----------------------------------------------------------------------------
@ -834,7 +849,9 @@ class SCOPED_LOCKABLE MutexLockMaybe {
private:
Mutex *const mu_;
MutexLockMaybe(const MutexLockMaybe&) = delete;
MutexLockMaybe(MutexLockMaybe&&) = delete;
MutexLockMaybe& operator=(const MutexLockMaybe&) = delete;
MutexLockMaybe& operator=(MutexLockMaybe&&) = delete;
};
// ReleaseableMutexLock
@ -856,7 +873,9 @@ class SCOPED_LOCKABLE ReleasableMutexLock {
private:
Mutex *mu_;
ReleasableMutexLock(const ReleasableMutexLock&) = delete;
ReleasableMutexLock(ReleasableMutexLock&&) = delete;
ReleasableMutexLock& operator=(const ReleasableMutexLock&) = delete;
ReleasableMutexLock& operator=(ReleasableMutexLock&&) = delete;
};
#ifdef ABSL_INTERNAL_USE_NONPROD_MUTEX