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- a0673e81da7ee7e322283e518331a4cdaeca837b Internal change by Abseil…
… Team <absl-team@google.com> - 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
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| Original file line number | Diff line number | Diff line change |
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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. | ||
| // | ||
| // Functions for directly invoking mmap() via syscall, avoiding the case where | ||
| // mmap() has been locally overridden. | ||
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| #ifndef ABSL_BASE_INTERNAL_DIRECT_MMAP_H_ | ||
| #define ABSL_BASE_INTERNAL_DIRECT_MMAP_H_ | ||
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| #include "absl/base/config.h" | ||
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| #if ABSL_HAVE_MMAP | ||
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| #include <sys/mman.h> | ||
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| #ifdef __linux__ | ||
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| #include <sys/types.h> | ||
| #ifdef __BIONIC__ | ||
| #include <sys/syscall.h> | ||
| #else | ||
| #include <syscall.h> | ||
| #endif | ||
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| #include <linux/unistd.h> | ||
| #include <unistd.h> | ||
| #include <cerrno> | ||
| #include <cstdarg> | ||
| #include <cstdint> | ||
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| #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__ | ||
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| // 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__ | ||
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| namespace absl { | ||
| namespace base_internal { | ||
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| // 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 | ||
| } | ||
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| inline int DirectMunmap(void* start, size_t length) { | ||
| return static_cast<int>(syscall(SYS_munmap, start, length)); | ||
| } | ||
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| } // namespace base_internal | ||
| } // namespace absl | ||
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| #else // !__linux__ | ||
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| // For non-linux platforms where we have mmap, just dispatch directly to the | ||
| // actual mmap()/munmap() methods. | ||
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| 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); | ||
| } | ||
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| inline int DirectMunmap(void* start, size_t length) { | ||
| return munmap(start, length); | ||
| } | ||
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| #endif // __linux__ | ||
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| #endif // ABSL_HAVE_MMAP | ||
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| #endif // ABSL_BASE_INTERNAL_DIRECT_MMAP_H_ |
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