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Diffstat (limited to 'absl/base/internal/malloc_hook_mmap_linux.inc')
| -rw-r--r-- | absl/base/internal/malloc_hook_mmap_linux.inc | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/absl/base/internal/malloc_hook_mmap_linux.inc b/absl/base/internal/malloc_hook_mmap_linux.inc new file mode 100644 index 000000000000..059ded57626d --- /dev/null +++ b/absl/base/internal/malloc_hook_mmap_linux.inc @@ -0,0 +1,236 @@ +// 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 |