Initial Commit

absl/base/internal/malloc_hook_mmap_linux.inc

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+// 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.
+//
+// We define mmap() and mmap64(), which somewhat reimplements libc's mmap
+// syscall stubs.  Unfortunately libc only exports the stubs via weak symbols
+// (which we're overriding with our mmap64() and mmap() wrappers) so we can't
+// just call through to them.
+
+#ifndef __linux__
+# error Should only be including malloc_hook_mmap_linux.h on linux systems.
+#endif
+
+#include <sys/mman.h>
+#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, SYS_munmap, and SYS_mremap 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
+#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.
+
+// Put all callers of MallocHook::Invoke* in this module into
+// malloc_hook section,
+// so that MallocHook::GetCallerStackTrace can function accurately:
+
+// Make sure mmap doesn't get #define'd away by <sys/mman.h>
+# undef mmap
+
+extern "C" {
+ABSL_ATTRIBUTE_SECTION(malloc_hook)
+void* mmap64(void* start, size_t length, int prot, int flags, int fd,
+             off64_t offset) __THROW;
+ABSL_ATTRIBUTE_SECTION(malloc_hook)
+void* mmap(void* start, size_t length, int prot, int flags, int fd,
+           off_t offset) __THROW;
+ABSL_ATTRIBUTE_SECTION(malloc_hook)
+int munmap(void* start, size_t length) __THROW;
+ABSL_ATTRIBUTE_SECTION(malloc_hook)
+void* mremap(void* old_addr, size_t old_size, size_t new_size, int flags,
+             ...) __THROW;
+ABSL_ATTRIBUTE_SECTION(malloc_hook) void* sbrk(ptrdiff_t increment) __THROW;
+}
+
+extern "C" void* mmap64(void *start, size_t length, int prot, int flags,
+                        int fd, off64_t offset) __THROW {
+  absl::base_internal::MallocHook::InvokePreMmapHook(start, length, prot, flags,
+                                                     fd, offset);
+  void *result;
+  if (!absl::base_internal::MallocHook::InvokeMmapReplacement(
+          start, length, prot, flags, fd, offset, &result)) {
+    result = do_mmap64(start, length, prot, flags, fd, offset);
+  }
+  absl::base_internal::MallocHook::InvokeMmapHook(result, start, length, prot,
+                                                  flags, fd, offset);
+  return result;
+}
+
+# if !defined(__USE_FILE_OFFSET64) || !defined(__REDIRECT_NTH)
+
+extern "C" void* mmap(void *start, size_t length, int prot, int flags,
+                      int fd, off_t offset) __THROW {
+  absl::base_internal::MallocHook::InvokePreMmapHook(start, length, prot, flags,
+                                                     fd, offset);
+  void *result;
+  if (!absl::base_internal::MallocHook::InvokeMmapReplacement(
+          start, length, prot, flags, fd, offset, &result)) {
+    result = do_mmap64(start, length, prot, flags, fd,
+                       static_cast<size_t>(offset)); // avoid sign extension
+  }
+  absl::base_internal::MallocHook::InvokeMmapHook(result, start, length, prot,
+                                                  flags, fd, offset);
+  return result;
+}
+
+# endif  // !defined(__USE_FILE_OFFSET64) || !defined(__REDIRECT_NTH)
+
+extern "C" int munmap(void* start, size_t length) __THROW {
+  absl::base_internal::MallocHook::InvokeMunmapHook(start, length);
+  int result;
+  if (!absl::base_internal::MallocHook::InvokeMunmapReplacement(start, length,
+                                                                &result)) {
+    result = syscall(SYS_munmap, start, length);
+  }
+  return result;
+}
+
+extern "C" void* mremap(void* old_addr, size_t old_size, size_t new_size,
+                        int flags, ...) __THROW {
+  va_list ap;
+  va_start(ap, flags);
+  void *new_address = va_arg(ap, void *);
+  va_end(ap);
+  void* result = reinterpret_cast<void*>(
+      syscall(SYS_mremap, old_addr, old_size, new_size, flags, new_address));
+  absl::base_internal::MallocHook::InvokeMremapHook(
+      result, old_addr, old_size, new_size, flags, new_address);
+  return result;
+}
+
+// sbrk cannot be intercepted on Android as there is no mechanism to
+// invoke the original sbrk (since there is no __sbrk as with glibc).
+#if !defined(__BIONIC__)
+// libc's version:
+extern "C" void* __sbrk(ptrdiff_t increment);
+
+extern "C" void* sbrk(ptrdiff_t increment) __THROW {
+  absl::base_internal::MallocHook::InvokePreSbrkHook(increment);
+  void *result = __sbrk(increment);
+  absl::base_internal::MallocHook::InvokeSbrkHook(result, increment);
+  return result;
+}
+#endif  // !defined(__BIONIC__)
+
+namespace absl {
+namespace base_internal {
+
+/*static*/void* MallocHook::UnhookedMMap(void *start, size_t length, int prot,
+                                         int flags, int fd, off_t offset) {
+  void* result;
+  if (!MallocHook::InvokeMmapReplacement(
+          start, length, prot, flags, fd, offset, &result)) {
+    result = do_mmap64(start, length, prot, flags, fd, offset);
+  }
+  return result;
+}
+
+/*static*/int MallocHook::UnhookedMUnmap(void *start, size_t length) {
+  int result;
+  if (!MallocHook::InvokeMunmapReplacement(start, length, &result)) {
+    result = syscall(SYS_munmap, start, length);
+  }
+  return result;
+}
+
+}  // namespace base_internal
+}  // namespace absl