diff --git a/android-elf-cleaner.cbp b/android-elf-cleaner.cbp new file mode 100644 index 0000000..7813747 --- /dev/null +++ b/android-elf-cleaner.cbp @@ -0,0 +1,52 @@ + + + + + + diff --git a/android-elf-cleaner.cpp b/android-elf-cleaner.cpp new file mode 100644 index 0000000..3b182dd --- /dev/null +++ b/android-elf-cleaner.cpp @@ -0,0 +1,299 @@ + +/// Windows MinGW build version adapted from PS +/// https://github.com/termux/termux-elf-cleaner +/// using mapping: https://github.com/mandreyel/mio + +#include "mio.hpp" +#include +#include +#include +#include +#include + +#ifndef _WIN32 +#include +#endif + +#include +#include +#include + +#ifndef __ANDROID_API__ +#define __ANDROID_API__ 21 +#endif + +// Include a local elf.h copy as not all platforms have it. +#include "elf.h" + +#define DT_GNU_HASH 0x6ffffef5 +#define DT_VERSYM 0x6ffffff0 +#define DT_FLAGS_1 0x6ffffffb +#define DT_VERNEEDED 0x6ffffffe +#define DT_VERNEEDNUM 0x6fffffff + +#define DF_1_NOW 0x00000001 /* Set RTLD_NOW for this object. */ +#define DF_1_GLOBAL 0x00000002 /* Set RTLD_GLOBAL for this object. */ +#define DF_1_NODELETE 0x00000008 /* Set RTLD_NODELETE for this object.*/ + +#if __ANDROID_API__ < 23 +#define SUPPORTED_DT_FLAGS_1 (DF_1_NOW | DF_1_GLOBAL) +#else +// The supported DT_FLAGS_1 values as of Android 6.0. +#define SUPPORTED_DT_FLAGS_1 (DF_1_NOW | DF_1_GLOBAL | DF_1_NODELETE) +#endif + +template +bool process_elf(uint8_t* bytes, size_t elf_file_size, char const* file_name) +{ + if (sizeof(ElfSectionHeaderType) > elf_file_size) + { + fprintf(stderr, "termux-elf-cleaner: Elf header for '%s' would end at %zu but file size only %zu\n", file_name, sizeof(ElfSectionHeaderType), elf_file_size); + return false; + } + ElfHeaderType* elf_hdr = reinterpret_cast(bytes); + + size_t last_section_header_byte = elf_hdr->e_shoff + sizeof(ElfSectionHeaderType) * elf_hdr->e_shnum; + if (last_section_header_byte > elf_file_size) + { + fprintf(stderr, "termux-elf-cleaner: Section header for '%s' would end at %zu but file size only %zu\n", file_name, last_section_header_byte, elf_file_size); + return false; + } + ElfSectionHeaderType* section_header_table = reinterpret_cast(bytes + elf_hdr->e_shoff); + + for (unsigned int i = 1; i < elf_hdr->e_shnum; i++) + { + ElfSectionHeaderType* section_header_entry = section_header_table + i; + if (section_header_entry->sh_type == SHT_DYNAMIC) + { + size_t const last_dynamic_section_byte = section_header_entry->sh_offset + section_header_entry->sh_size; + if (last_dynamic_section_byte > elf_file_size) + { + fprintf(stderr, "termux-elf-cleaner: Dynamic section for '%s' would end at %zu but file size only %zu\n", file_name, last_dynamic_section_byte, elf_file_size); + return false; + } + + size_t const dynamic_section_entries = section_header_entry->sh_size / sizeof(ElfDynamicSectionEntryType); + ElfDynamicSectionEntryType* const dynamic_section = + reinterpret_cast(bytes + section_header_entry->sh_offset); + + unsigned int last_nonnull_entry_idx = 0; + for (unsigned int j = dynamic_section_entries - 1; j > 0; j--) + { + ElfDynamicSectionEntryType* dynamic_section_entry = dynamic_section + j; + if (dynamic_section_entry->d_tag != DT_NULL) + { + last_nonnull_entry_idx = j; + break; + } + } + + for (unsigned int j = 0; j < dynamic_section_entries; j++) + { + ElfDynamicSectionEntryType* dynamic_section_entry = dynamic_section + j; + char const* removed_name = NULL; + switch (dynamic_section_entry->d_tag) + { +#if __ANDROID_API__ <= 21 + case DT_GNU_HASH: + removed_name = "DT_GNU_HASH"; + break; +#endif +#if __ANDROID_API__ < 23 + case DT_VERSYM: + removed_name = "DT_VERSYM"; + break; + case DT_VERNEEDED: + removed_name = "DT_VERNEEDED"; + break; + case DT_VERNEEDNUM: + removed_name = "DT_VERNEEDNUM"; + break; + case DT_VERDEF: + removed_name = "DT_VERDEF"; + break; + case DT_VERDEFNUM: + removed_name = "DT_VERDEFNUM"; + break; +#endif + case DT_RPATH: + removed_name = "DT_RPATH"; + break; +#if __ANDROID_API__ < 24 + case DT_RUNPATH: + removed_name = "DT_RUNPATH"; + break; +#endif + } + if (removed_name != NULL) + { + printf("termux-elf-cleaner: Removing the %s dynamic section entry from '%s'\n", removed_name, file_name); + // Tag the entry with DT_NULL and put it last: + dynamic_section_entry->d_tag = DT_NULL; + // Decrease j to process new entry index: + std::swap(dynamic_section[j--], dynamic_section[last_nonnull_entry_idx--]); + } + else if (dynamic_section_entry->d_tag == DT_FLAGS_1) + { + // Remove unsupported DF_1_* flags to avoid linker warnings. + int orig_d_val = + dynamic_section_entry->d_un.d_val; + int new_d_val = + (orig_d_val & SUPPORTED_DT_FLAGS_1); + if (new_d_val != orig_d_val) + { + printf("termux-elf-cleaner: Replacing unsupported DF_1_* flags %llu with %llu in '%s'\n", + (unsigned long long) orig_d_val, + (unsigned long long) new_d_val, + file_name); + dynamic_section_entry->d_un.d_val = new_d_val; + } + } + } + } +#if __ANDROID_API__ < 23 + else if (section_header_entry->sh_type == SHT_GNU_verdef || + section_header_entry->sh_type == SHT_GNU_verneed || + section_header_entry->sh_type == SHT_GNU_versym) + { + printf("termux-elf-cleaner: Removing version section from '%s'\n", file_name); + section_header_entry->sh_type = SHT_NULL; + } +#endif + } + return true; +} + + +int main(int argc, char const** argv) +{ + if (argc < 2 || (argc == 2 && strcmp(argv[1], "-h")==0)) + { + fprintf(stderr, "usage: %s \n", argv[0]); + fprintf(stderr, "\nProcesses ELF files to remove unsupported section types\n" + "and dynamic section entries which the Android linker (API %d)\nwarns about.\n", + __ANDROID_API__); + return 127; + } + + for (int i = 1; i < argc; i++) + { + char const *file_name = argv[i]; + +# ifdef _WIN32 + + std::error_code error{}; + mio::mmap_sink rw_mmap = mio::make_mmap_sink(file_name, 0, mio::map_entire_file, error); + + if (error) + { + const auto& errmsg = error.message(); + printf("error mapping file: %s, exiting...\n", errmsg.c_str()); + return error.value(); + } + + void *mem = &rw_mmap[0]; + size_t const file_size = rw_mmap.size(); + +# else + + int fd = open(file_name, O_RDWR); + if (fd < 0) + { + char* error_message; + if (asprintf(&error_message, "open(\"%s\")", file_name) == -1) + error_message = (char*) "open()"; + perror(error_message); + return 1; + } + + struct stat st; + if (fstat(fd, &st) < 0) + { + perror("fstat()"); + return 1; + } + + size_t const file_size = static_cast(st.st_size); + + if (file_size < sizeof(Elf32_Ehdr)) + { + close(fd); + continue; + } + + void* mem = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (mem == MAP_FAILED) + { + perror("mmap()"); + return 1; + } +# endif + + uint8_t* bytes = reinterpret_cast(mem); + if (!(bytes[0] == 0x7F && bytes[1] == 'E' && bytes[2] == 'L' && bytes[3] == 'F')) + { + // Not the ELF magic number. +# ifdef _WIN32 + rw_mmap.unmap(); +# else + munmap(mem, file_size); + close(fd); +# endif + continue; + } + + if (bytes[/*EI_DATA*/5] != 1) + { + fprintf(stderr, "termux-elf-cleaner: Not little endianness in '%s'\n", file_name); +# ifdef _WIN32 + rw_mmap.unmap(); +# else + munmap(mem, file_size); + close(fd); +# endif + continue; + } + + uint8_t const bit_value = bytes[/*EI_CLASS*/4]; + if (bit_value == 1) + { + if (!process_elf(bytes, file_size, file_name)) + return 1; + } + else if (bit_value == 2) + { + if (!process_elf(bytes, file_size, file_name)) + return 1; + } + else + { + printf("termux-elf-cleaner: Incorrect bit value %d in '%s'\n", bit_value, file_name); + return 1; + } + +# ifdef _WIN32 + rw_mmap.sync(error); + if (error) + { + const auto& errmsg = error.message(); + printf("error mapping sync: %s, exiting...\n", errmsg.c_str()); + return error.value(); + } + rw_mmap.unmap(); + +# else + + if (msync(mem, file_size, MS_SYNC) < 0) + { + perror("msync()"); + return 1; + } + + munmap(mem, st.st_size); + close(fd); +# endif + } + return 0; +} diff --git a/dist/README.md b/dist/README.md new file mode 100644 index 0000000..9a62446 --- /dev/null +++ b/dist/README.md @@ -0,0 +1,6 @@ +# Windows MinGW build version adapted from PS + +- origin: https://github.com/termux/termux-elf-cleaner +- using mapping: https://github.com/mandreyel/mio +- download [WIN32 binary](https://github.com/ClnViewer/termux-elf-cleaner/raw/master/dist/android-elf-cleaner.zip) + diff --git a/dist/android-elf-cleaner.zip b/dist/android-elf-cleaner.zip new file mode 100644 index 0000000..9035659 Binary files /dev/null and b/dist/android-elf-cleaner.zip differ diff --git a/mio.hpp b/mio.hpp new file mode 100644 index 0000000..1d43307 --- /dev/null +++ b/mio.hpp @@ -0,0 +1,1751 @@ +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_MMAP_HEADER +#define MIO_MMAP_HEADER + +// #include "mio/page.hpp" +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_PAGE_HEADER +#define MIO_PAGE_HEADER + +#ifdef _WIN32 +# include +#else +# include +#endif + +namespace mio { + +/** + * This is used by `basic_mmap` to determine whether to create a read-only or + * a read-write memory mapping. + */ +enum class access_mode +{ + read, + write +}; + +/** + * Determines the operating system's page allocation granularity. + * + * On the first call to this function, it invokes the operating system specific syscall + * to determine the page size, caches the value, and returns it. Any subsequent call to + * this function serves the cached value, so no further syscalls are made. + */ +inline size_t page_size() +{ + static const size_t page_size = [] + { +#ifdef _WIN32 + SYSTEM_INFO SystemInfo; + GetSystemInfo(&SystemInfo); + return SystemInfo.dwAllocationGranularity; +#else + return sysconf(_SC_PAGE_SIZE); +#endif + }(); + return page_size; +} + +/** + * Alligns `offset` to the operating's system page size such that it subtracts the + * difference until the nearest page boundary before `offset`, or does nothing if + * `offset` is already page aligned. + */ +inline size_t make_offset_page_aligned(size_t offset) noexcept +{ + const size_t page_size_ = page_size(); + // Use integer division to round down to the nearest page alignment. + return offset / page_size_ * page_size_; +} + +} // namespace mio + +#endif // MIO_PAGE_HEADER + + +#include +#include +#include +#include + +#ifdef _WIN32 +# ifndef WIN32_LEAN_AND_MEAN +# define WIN32_LEAN_AND_MEAN +# endif // WIN32_LEAN_AND_MEAN +# include +#else // ifdef _WIN32 +# define INVALID_HANDLE_VALUE -1 +#endif // ifdef _WIN32 + +namespace mio { + +// This value may be provided as the `length` parameter to the constructor or +// `map`, in which case a memory mapping of the entire file is created. +enum { map_entire_file = 0 }; + +#ifdef _WIN32 +using file_handle_type = HANDLE; +#else +using file_handle_type = int; +#endif + +// This value represents an invalid file handle type. This can be used to +// determine whether `basic_mmap::file_handle` is valid, for example. +const static file_handle_type invalid_handle = INVALID_HANDLE_VALUE; + +template +struct basic_mmap +{ + using value_type = ByteT; + using size_type = size_t; + using reference = value_type&; + using const_reference = const value_type&; + using pointer = value_type*; + using const_pointer = const value_type*; + using difference_type = std::ptrdiff_t; + using iterator = pointer; + using const_iterator = const_pointer; + using reverse_iterator = std::reverse_iterator; + using const_reverse_iterator = std::reverse_iterator; + using iterator_category = std::random_access_iterator_tag; + using handle_type = file_handle_type; + + static_assert(sizeof(ByteT) == sizeof(char), "ByteT must be the same size as char."); + +private: + // Points to the first requested byte, and not to the actual start of the mapping. + pointer data_ = nullptr; + + // Length, in bytes, requested by user, which may not be the length of the full + // mapping, and the entire length of the full mapping. + size_type length_ = 0; + size_type mapped_length_ = 0; + + // Letting user map a file using both an existing file handle and a path introcudes + // On POSIX, we only need a file handle to create a mapping, while on Windows + // systems the file handle is necessary to retrieve a file mapping handle, but any + // subsequent operations on the mapped region must be done through the latter. + handle_type file_handle_ = INVALID_HANDLE_VALUE; +#ifdef _WIN32 + handle_type file_mapping_handle_ = INVALID_HANDLE_VALUE; +#endif + + // Letting user map a file using both an existing file handle and a path + // introcudes some complexity in that we must not close the file handle if + // user provided it, but we must close it if we obtained it using the + // provided path. For this reason, this flag is used to determine when to + // close file_handle_. + bool is_handle_internal_; + +public: + /** + * The default constructed mmap object is in a non-mapped state, that is, + * any operation that attempts to access nonexistent underlying data will + * result in undefined behaviour/segmentation faults. + */ + basic_mmap() = default; + +#ifdef __cpp_exceptions + /** + * The same as invoking the `map` function, except any error that may occur + * while establishing the mapping is wrapped in a `std::system_error` and is + * thrown. + */ + template + basic_mmap(const String& path, const size_type offset = 0, const size_type length = map_entire_file) + { + std::error_code error; + map(path, offset, length, error); + if(error) { throw std::system_error(error); } + } + + /** + * The same as invoking the `map` function, except any error that may occur + * while establishing the mapping is wrapped in a `std::system_error` and is + * thrown. + */ + basic_mmap(const handle_type handle, const size_type offset = 0, const size_type length = map_entire_file) + { + std::error_code error; + map(handle, offset, length, error); + if(error) { throw std::system_error(error); } + } +#endif // __cpp_exceptions + + /** + * `basic_mmap` has single-ownership semantics, so transferring ownership + * may only be accomplished by moving the object. + */ + basic_mmap(const basic_mmap&) = delete; + basic_mmap(basic_mmap&&); + basic_mmap& operator=(const basic_mmap&) = delete; + basic_mmap& operator=(basic_mmap&&); + + /** + * If this is a read-write mapping, the destructor invokes sync. Regardless + * of the access mode, unmap is invoked as a final step. + */ + ~basic_mmap(); + + /** + * On UNIX systems 'file_handle' and 'mapping_handle' are the same. On Windows, + * however, a mapped region of a file gets its own handle, which is returned by + * 'mapping_handle'. + */ + handle_type file_handle() const noexcept { return file_handle_; } + handle_type mapping_handle() const noexcept; + + /** Returns whether a valid memory mapping has been created. */ + bool is_open() const noexcept { return file_handle_ != invalid_handle; } + + /** + * Returns true if no mapping was established, that is, conceptually the + * same as though the length that was mapped was 0. This function is + * provided so that this class has Container semantics. + */ + bool empty() const noexcept { return length() == 0; } + + /** Returns true if a mapping was established. */ + bool is_mapped() const noexcept; + + /** + * `size` and `length` both return the logical length, i.e. the number of bytes + * user requested to be mapped, while `mapped_length` returns the actual number of + * bytes that were mapped which is a multiple of the underlying operating system's + * page allocation granularity. + */ + size_type size() const noexcept { return length(); } + size_type length() const noexcept { return length_; } + size_type mapped_length() const noexcept { return mapped_length_; } + + /** + * Returns the offset, relative to the file's start, at which the mapping was + * requested to be created. + */ + size_type offset() const noexcept { return mapped_length_ - length_; } + + /** + * Returns a pointer to the first requested byte, or `nullptr` if no memory mapping + * exists. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > pointer data() noexcept { return data_; } + const_pointer data() const noexcept { return data_; } + + /** + * Returns an iterator to the first requested byte, if a valid memory mapping + * exists, otherwise this function call is undefined behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > iterator begin() noexcept { return data(); } + const_iterator begin() const noexcept { return data(); } + const_iterator cbegin() const noexcept { return data(); } + + /** + * Returns an iterator one past the last requested byte, if a valid memory mapping + * exists, otherwise this function call is undefined behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > iterator end() noexcept { return data() + length(); } + const_iterator end() const noexcept { return data() + length(); } + const_iterator cend() const noexcept { return data() + length(); } + + /** + * Returns a reverse iterator to the last memory mapped byte, if a valid + * memory mapping exists, otherwise this function call is undefined + * behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > reverse_iterator rbegin() noexcept { return reverse_iterator(end()); } + const_reverse_iterator rbegin() const noexcept + { return const_reverse_iterator(end()); } + const_reverse_iterator crbegin() const noexcept + { return const_reverse_iterator(end()); } + + /** + * Returns a reverse iterator past the first mapped byte, if a valid memory + * mapping exists, otherwise this function call is undefined behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > reverse_iterator rend() noexcept { return reverse_iterator(begin()); } + const_reverse_iterator rend() const noexcept + { return const_reverse_iterator(begin()); } + const_reverse_iterator crend() const noexcept + { return const_reverse_iterator(begin()); } + + /** + * Returns a reference to the `i`th byte from the first requested byte (as returned + * by `data`). If this is invoked when no valid memory mapping has been created + * prior to this call, undefined behaviour ensues. + */ + reference operator[](const size_type i) noexcept { return data_[i]; } + const_reference operator[](const size_type i) const noexcept { return data_[i]; } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `path`, which must be a path to an existing file, is used to retrieve a file + * handle (which is closed when the object destructs or `unmap` is called), which is + * then used to memory map the requested region. Upon failure, `error` is set to + * indicate the reason and the object remains in an unmapped state. + * + * `offset` is the number of bytes, relative to the start of the file, where the + * mapping should begin. When specifying it, there is no need to worry about + * providing a value that is aligned with the operating system's page allocation + * granularity. This is adjusted by the implementation such that the first requested + * byte (as returned by `data` or `begin`), so long as `offset` is valid, will be at + * `offset` from the start of the file. + * + * `length` is the number of bytes to map. It may be `map_entire_file`, in which + * case a mapping of the entire file is created. + */ + template + void map(const String& path, const size_type offset, + const size_type length, std::error_code& error); + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `path`, which must be a path to an existing file, is used to retrieve a file + * handle (which is closed when the object destructs or `unmap` is called), which is + * then used to memory map the requested region. Upon failure, `error` is set to + * indicate the reason and the object remains in an unmapped state. + * + * The entire file is mapped. + */ + template + void map(const String& path, std::error_code& error) + { + map(path, 0, map_entire_file, error); + } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is + * unsuccesful, the reason is reported via `error` and the object remains in + * a state as if this function hadn't been called. + * + * `handle`, which must be a valid file handle, which is used to memory map the + * requested region. Upon failure, `error` is set to indicate the reason and the + * object remains in an unmapped state. + * + * `offset` is the number of bytes, relative to the start of the file, where the + * mapping should begin. When specifying it, there is no need to worry about + * providing a value that is aligned with the operating system's page allocation + * granularity. This is adjusted by the implementation such that the first requested + * byte (as returned by `data` or `begin`), so long as `offset` is valid, will be at + * `offset` from the start of the file. + * + * `length` is the number of bytes to map. It may be `map_entire_file`, in which + * case a mapping of the entire file is created. + */ + void map(const handle_type handle, const size_type offset, + const size_type length, std::error_code& error); + + /** + * Establishes a memory mapping with AccessMode. If the mapping is + * unsuccesful, the reason is reported via `error` and the object remains in + * a state as if this function hadn't been called. + * + * `handle`, which must be a valid file handle, which is used to memory map the + * requested region. Upon failure, `error` is set to indicate the reason and the + * object remains in an unmapped state. + * + * The entire file is mapped. + */ + void map(const handle_type handle, std::error_code& error) + { + map(handle, 0, map_entire_file, error); + } + + /** + * If a valid memory mapping has been created prior to this call, this call + * instructs the kernel to unmap the memory region and disassociate this object + * from the file. + * + * The file handle associated with the file that is mapped is only closed if the + * mapping was created using a file path. If, on the other hand, an existing + * file handle was used to create the mapping, the file handle is not closed. + */ + void unmap(); + + void swap(basic_mmap& other); + + /** Flushes the memory mapped page to disk. Errors are reported via `error`. */ + template + typename std::enable_if::type + sync(std::error_code& error); + + /** + * All operators compare the address of the first byte and size of the two mapped + * regions. + */ + +private: + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > pointer get_mapping_start() noexcept + { + return !data() ? nullptr : data() - offset(); + } + + const_pointer get_mapping_start() const noexcept + { + return !data() ? nullptr : data() - offset(); + } + + /** + * The destructor syncs changes to disk if `AccessMode` is `write`, but not + * if it's `read`, but since the destructor cannot be templated, we need to + * do SFINAE in a dedicated function, where one syncs and the other is a noop. + */ + template + typename std::enable_if::type + conditional_sync(); + template + typename std::enable_if::type conditional_sync(); +}; + +template +bool operator==(const basic_mmap& a, + const basic_mmap& b); + +template +bool operator!=(const basic_mmap& a, + const basic_mmap& b); + +template +bool operator<(const basic_mmap& a, + const basic_mmap& b); + +template +bool operator<=(const basic_mmap& a, + const basic_mmap& b); + +template +bool operator>(const basic_mmap& a, + const basic_mmap& b); + +template +bool operator>=(const basic_mmap& a, + const basic_mmap& b); + +/** + * This is the basis for all read-only mmap objects and should be preferred over + * directly using `basic_mmap`. + */ +template +using basic_mmap_source = basic_mmap; + +/** + * This is the basis for all read-write mmap objects and should be preferred over + * directly using `basic_mmap`. + */ +template +using basic_mmap_sink = basic_mmap; + +/** + * These aliases cover the most common use cases, both representing a raw byte stream + * (either with a char or an unsigned char/uint8_t). + */ +using mmap_source = basic_mmap_source; +using ummap_source = basic_mmap_source; + +using mmap_sink = basic_mmap_sink; +using ummap_sink = basic_mmap_sink; + +/** + * Convenience factory method that constructs a mapping for any `basic_mmap` or + * `basic_mmap` type. + */ +template< + typename MMap, + typename MappingToken +> MMap make_mmap(const MappingToken& token, + int64_t offset, int64_t length, std::error_code& error) +{ + MMap mmap; + mmap.map(token, offset, length, error); + return mmap; +} + +/** + * Convenience factory method. + * + * MappingToken may be a String (`std::string`, `std::string_view`, `const char*`, + * `std::filesystem::path`, `std::vector`, or similar), or a + * `mmap_source::handle_type`. + */ +template +mmap_source make_mmap_source(const MappingToken& token, mmap_source::size_type offset, + mmap_source::size_type length, std::error_code& error) +{ + return make_mmap(token, offset, length, error); +} + +template +mmap_source make_mmap_source(const MappingToken& token, std::error_code& error) +{ + return make_mmap_source(token, 0, map_entire_file, error); +} + +/** + * Convenience factory method. + * + * MappingToken may be a String (`std::string`, `std::string_view`, `const char*`, + * `std::filesystem::path`, `std::vector`, or similar), or a + * `mmap_sink::handle_type`. + */ +template +mmap_sink make_mmap_sink(const MappingToken& token, mmap_sink::size_type offset, + mmap_sink::size_type length, std::error_code& error) +{ + return make_mmap(token, offset, length, error); +} + +template +mmap_sink make_mmap_sink(const MappingToken& token, std::error_code& error) +{ + return make_mmap_sink(token, 0, map_entire_file, error); +} + +} // namespace mio + +// #include "detail/mmap.ipp" +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_BASIC_MMAP_IMPL +#define MIO_BASIC_MMAP_IMPL + +// #include "mio/mmap.hpp" + +// #include "mio/page.hpp" + +// #include "mio/detail/string_util.hpp" +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_STRING_UTIL_HEADER +#define MIO_STRING_UTIL_HEADER + +#include + +namespace mio { +namespace detail { + +template< + typename S, + typename C = typename std::decay::type, + typename = decltype(std::declval().data()), + typename = typename std::enable_if< + std::is_same::value +#ifdef _WIN32 + || std::is_same::value +#endif + >::type +> struct char_type_helper { + using type = typename C::value_type; +}; + +template +struct char_type { + using type = typename char_type_helper::type; +}; + +// TODO: can we avoid this brute force approach? +template<> +struct char_type { + using type = char; +}; + +template<> +struct char_type { + using type = char; +}; + +template +struct char_type { + using type = char; +}; + +template +struct char_type { + using type = char; +}; + +#ifdef _WIN32 +template<> +struct char_type { + using type = wchar_t; +}; + +template<> +struct char_type { + using type = wchar_t; +}; + +template +struct char_type { + using type = wchar_t; +}; + +template +struct char_type { + using type = wchar_t; +}; +#endif // _WIN32 + +template +struct is_c_str_helper +{ + static constexpr bool value = std::is_same< + CharT*, + // TODO: I'm so sorry for this... Can this be made cleaner? + typename std::add_pointer< + typename std::remove_cv< + typename std::remove_pointer< + typename std::decay< + S + >::type + >::type + >::type + >::type + >::value; +}; + +template +struct is_c_str +{ + static constexpr bool value = is_c_str_helper::value; +}; + +#ifdef _WIN32 +template +struct is_c_wstr +{ + static constexpr bool value = is_c_str_helper::value; +}; +#endif // _WIN32 + +template +struct is_c_str_or_c_wstr +{ + static constexpr bool value = is_c_str::value +#ifdef _WIN32 + || is_c_wstr::value +#endif + ; +}; + +template< + typename String, + typename = decltype(std::declval().data()), + typename = typename std::enable_if::value>::type +> const typename char_type::type* c_str(const String& path) +{ + return path.data(); +} + +template< + typename String, + typename = decltype(std::declval().empty()), + typename = typename std::enable_if::value>::type +> bool empty(const String& path) +{ + return path.empty(); +} + +template< + typename String, + typename = typename std::enable_if::value>::type +> const typename char_type::type* c_str(String path) +{ + return path; +} + +template< + typename String, + typename = typename std::enable_if::value>::type +> bool empty(String path) +{ + return !path || (*path == 0); +} + +} // namespace detail +} // namespace mio + +#endif // MIO_STRING_UTIL_HEADER + + +#include + +#ifndef _WIN32 +# include +# include +# include +# include +#endif + +namespace mio { +namespace detail { + +#ifdef _WIN32 +namespace win { + +/** Returns the 4 upper bytes of an 8-byte integer. */ +inline DWORD int64_high(int64_t n) noexcept +{ + return n >> 32; +} + +/** Returns the 4 lower bytes of an 8-byte integer. */ +inline DWORD int64_low(int64_t n) noexcept +{ + return n & 0xffffffff; +} + +template< + typename String, + typename = typename std::enable_if< + std::is_same::type, char>::value + >::type +> file_handle_type open_file_helper(const String& path, const access_mode mode) +{ + return ::CreateFileA(c_str(path), + mode == access_mode::read ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE, + FILE_SHARE_READ | FILE_SHARE_WRITE, + 0, + OPEN_EXISTING, + FILE_ATTRIBUTE_NORMAL, + 0); +} + +template +typename std::enable_if< + std::is_same::type, wchar_t>::value, + file_handle_type +>::type open_file_helper(const String& path, const access_mode mode) +{ + return ::CreateFileW(c_str(path), + mode == access_mode::read ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE, + FILE_SHARE_READ | FILE_SHARE_WRITE, + 0, + OPEN_EXISTING, + FILE_ATTRIBUTE_NORMAL, + 0); +} + +} // win +#endif // _WIN32 + +/** + * Returns the last platform specific system error (errno on POSIX and + * GetLastError on Win) as a `std::error_code`. + */ +inline std::error_code last_error() noexcept +{ + std::error_code error; +#ifdef _WIN32 + error.assign(GetLastError(), std::system_category()); +#else + error.assign(errno, std::system_category()); +#endif + return error; +} + +template +file_handle_type open_file(const String& path, const access_mode mode, + std::error_code& error) +{ + error.clear(); + if(detail::empty(path)) + { + error = std::make_error_code(std::errc::invalid_argument); + return invalid_handle; + } +#ifdef _WIN32 + const auto handle = win::open_file_helper(path, mode); +#else // POSIX + const auto handle = ::open(c_str(path), + mode == access_mode::read ? O_RDONLY : O_RDWR); +#endif + if(handle == invalid_handle) + { + error = detail::last_error(); + } + return handle; +} + +inline size_t query_file_size(file_handle_type handle, std::error_code& error) +{ + error.clear(); +#ifdef _WIN32 + LARGE_INTEGER file_size; + if(::GetFileSizeEx(handle, &file_size) == 0) + { + error = detail::last_error(); + return 0; + } + return static_cast(file_size.QuadPart); +#else // POSIX + struct stat sbuf; + if(::fstat(handle, &sbuf) == -1) + { + error = detail::last_error(); + return 0; + } + return sbuf.st_size; +#endif +} + +struct mmap_context +{ + char* data; + int64_t length; + int64_t mapped_length; +#ifdef _WIN32 + file_handle_type file_mapping_handle; +#endif +}; + +inline mmap_context memory_map(const file_handle_type file_handle, const int64_t offset, + const int64_t length, const access_mode mode, std::error_code& error) +{ + const int64_t aligned_offset = make_offset_page_aligned(offset); + const int64_t length_to_map = offset - aligned_offset + length; +#ifdef _WIN32 + const int64_t max_file_size = offset + length; + const auto file_mapping_handle = ::CreateFileMapping( + file_handle, + 0, + mode == access_mode::read ? PAGE_READONLY : PAGE_READWRITE, + win::int64_high(max_file_size), + win::int64_low(max_file_size), + 0); + if(file_mapping_handle == invalid_handle) + { + error = detail::last_error(); + return {}; + } + char* mapping_start = static_cast(::MapViewOfFile( + file_mapping_handle, + mode == access_mode::read ? FILE_MAP_READ : FILE_MAP_WRITE, + win::int64_high(aligned_offset), + win::int64_low(aligned_offset), + length_to_map)); + if(mapping_start == nullptr) + { + error = detail::last_error(); + return {}; + } +#else // POSIX + char* mapping_start = static_cast(::mmap( + 0, // Don't give hint as to where to map. + length_to_map, + mode == access_mode::read ? PROT_READ : PROT_WRITE, + MAP_SHARED, + file_handle, + aligned_offset)); + if(mapping_start == MAP_FAILED) + { + error = detail::last_error(); + return {}; + } +#endif + mmap_context ctx; + ctx.data = mapping_start + offset - aligned_offset; + ctx.length = length; + ctx.mapped_length = length_to_map; +#ifdef _WIN32 + ctx.file_mapping_handle = file_mapping_handle; +#endif + return ctx; +} + +} // namespace detail + +// -- basic_mmap -- + +template +basic_mmap::~basic_mmap() +{ + conditional_sync(); + unmap(); +} + +template +basic_mmap::basic_mmap(basic_mmap&& other) + : data_(std::move(other.data_)) + , length_(std::move(other.length_)) + , mapped_length_(std::move(other.mapped_length_)) + , file_handle_(std::move(other.file_handle_)) +#ifdef _WIN32 + , file_mapping_handle_(std::move(other.file_mapping_handle_)) +#endif + , is_handle_internal_(std::move(other.is_handle_internal_)) +{ + other.data_ = nullptr; + other.length_ = other.mapped_length_ = 0; + other.file_handle_ = invalid_handle; +#ifdef _WIN32 + other.file_mapping_handle_ = invalid_handle; +#endif +} + +template +basic_mmap& +basic_mmap::operator=(basic_mmap&& other) +{ + if(this != &other) + { + // First the existing mapping needs to be removed. + unmap(); + data_ = std::move(other.data_); + length_ = std::move(other.length_); + mapped_length_ = std::move(other.mapped_length_); + file_handle_ = std::move(other.file_handle_); +#ifdef _WIN32 + file_mapping_handle_ = std::move(other.file_mapping_handle_); +#endif + is_handle_internal_ = std::move(other.is_handle_internal_); + + // The moved from basic_mmap's fields need to be reset, because + // otherwise other's destructor will unmap the same mapping that was + // just moved into this. + other.data_ = nullptr; + other.length_ = other.mapped_length_ = 0; + other.file_handle_ = invalid_handle; +#ifdef _WIN32 + other.file_mapping_handle_ = invalid_handle; +#endif + other.is_handle_internal_ = false; + } + return *this; +} + +template +typename basic_mmap::handle_type +basic_mmap::mapping_handle() const noexcept +{ +#ifdef _WIN32 + return file_mapping_handle_; +#else + return file_handle_; +#endif +} + +template +template +void basic_mmap::map(const String& path, const size_type offset, + const size_type length, std::error_code& error) +{ + error.clear(); + if(detail::empty(path)) + { + error = std::make_error_code(std::errc::invalid_argument); + return; + } + const auto handle = detail::open_file(path, AccessMode, error); + if(error) + { + return; + } + + map(handle, offset, length, error); + // This MUST be after the call to map, as that sets this to true. + if(!error) + { + is_handle_internal_ = true; + } +} + +template +void basic_mmap::map(const handle_type handle, + const size_type offset, const size_type length, std::error_code& error) +{ + error.clear(); + if(handle == invalid_handle) + { + error = std::make_error_code(std::errc::bad_file_descriptor); + return; + } + + const auto file_size = detail::query_file_size(handle, error); + if(error) + { + return; + } + + if(offset + length > file_size) + { + error = std::make_error_code(std::errc::invalid_argument); + return; + } + + const auto ctx = detail::memory_map(handle, offset, + length == map_entire_file ? (file_size - offset) : length, + AccessMode, error); + if(!error) + { + // We must unmap the previous mapping that may have existed prior to this call. + // Note that this must only be invoked after a new mapping has been created in + // order to provide the strong guarantee that, should the new mapping fail, the + // `map` function leaves this instance in a state as though the function had + // never been invoked. + unmap(); + file_handle_ = handle; + is_handle_internal_ = false; + data_ = reinterpret_cast(ctx.data); + length_ = ctx.length; + mapped_length_ = ctx.mapped_length; +#ifdef _WIN32 + file_mapping_handle_ = ctx.file_mapping_handle; +#endif + } +} + +template +template +typename std::enable_if::type +basic_mmap::sync(std::error_code& error) +{ + error.clear(); + if(!is_open()) + { + error = std::make_error_code(std::errc::bad_file_descriptor); + return; + } + + if(data()) + { +#ifdef _WIN32 + if(::FlushViewOfFile(get_mapping_start(), mapped_length_) == 0 + || ::FlushFileBuffers(file_handle_) == 0) +#else // POSIX + if(::msync(get_mapping_start(), mapped_length_, MS_SYNC) != 0) +#endif + { + error = detail::last_error(); + return; + } + } +#ifdef _WIN32 + if(::FlushFileBuffers(file_handle_) == 0) + { + error = detail::last_error(); + } +#endif +} + +template +void basic_mmap::unmap() +{ + if(!is_open()) { return; } + // TODO do we care about errors here? +#ifdef _WIN32 + if(is_mapped()) + { + ::UnmapViewOfFile(get_mapping_start()); + ::CloseHandle(file_mapping_handle_); + } +#else // POSIX + if(data_) { ::munmap(const_cast(get_mapping_start()), mapped_length_); } +#endif + + // If file_handle_ was obtained by our opening it (when map is called with a path, + // rather than an existing file handle), we need to close it, otherwise it must not + // be closed as it may still be used outside this instance. + if(is_handle_internal_) + { +#ifdef _WIN32 + ::CloseHandle(file_handle_); +#else // POSIX + ::close(file_handle_); +#endif + } + + // Reset fields to their default values. + data_ = nullptr; + length_ = mapped_length_ = 0; + file_handle_ = invalid_handle; +#ifdef _WIN32 + file_mapping_handle_ = invalid_handle; +#endif +} + +template +bool basic_mmap::is_mapped() const noexcept +{ +#ifdef _WIN32 + return file_mapping_handle_ != invalid_handle; +#else // POSIX + return is_open(); +#endif +} + +template +void basic_mmap::swap(basic_mmap& other) +{ + if(this != &other) + { + using std::swap; + swap(data_, other.data_); + swap(file_handle_, other.file_handle_); +#ifdef _WIN32 + swap(file_mapping_handle_, other.file_mapping_handle_); +#endif + swap(length_, other.length_); + swap(mapped_length_, other.mapped_length_); + swap(is_handle_internal_, other.is_handle_internal_); + } +} + +template +template +typename std::enable_if::type +basic_mmap::conditional_sync() +{ + // This is invoked from the destructor, so not much we can do about + // failures here. + std::error_code ec; + sync(ec); +} + +template +template +typename std::enable_if::type +basic_mmap::conditional_sync() +{ + // noop +} + +template +bool operator==(const basic_mmap& a, + const basic_mmap& b) +{ + return a.data() == b.data() + && a.size() == b.size(); +} + +template +bool operator!=(const basic_mmap& a, + const basic_mmap& b) +{ + return !(a == b); +} + +template +bool operator<(const basic_mmap& a, + const basic_mmap& b) +{ + if(a.data() == b.data()) { return a.size() < b.size(); } + return a.data() < b.data(); +} + +template +bool operator<=(const basic_mmap& a, + const basic_mmap& b) +{ + return !(a > b); +} + +template +bool operator>(const basic_mmap& a, + const basic_mmap& b) +{ + if(a.data() == b.data()) { return a.size() > b.size(); } + return a.data() > b.data(); +} + +template +bool operator>=(const basic_mmap& a, + const basic_mmap& b) +{ + return !(a < b); +} + +} // namespace mio + +#endif // MIO_BASIC_MMAP_IMPL + + +#endif // MIO_MMAP_HEADER +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_PAGE_HEADER +#define MIO_PAGE_HEADER + +#ifdef _WIN32 +# include +#else +# include +#endif + +namespace mio { + +/** + * This is used by `basic_mmap` to determine whether to create a read-only or + * a read-write memory mapping. + */ +enum class access_mode +{ + read, + write +}; + +/** + * Determines the operating system's page allocation granularity. + * + * On the first call to this function, it invokes the operating system specific syscall + * to determine the page size, caches the value, and returns it. Any subsequent call to + * this function serves the cached value, so no further syscalls are made. + */ +inline size_t page_size() +{ + static const size_t page_size = [] + { +#ifdef _WIN32 + SYSTEM_INFO SystemInfo; + GetSystemInfo(&SystemInfo); + return SystemInfo.dwAllocationGranularity; +#else + return sysconf(_SC_PAGE_SIZE); +#endif + }(); + return page_size; +} + +/** + * Alligns `offset` to the operating's system page size such that it subtracts the + * difference until the nearest page boundary before `offset`, or does nothing if + * `offset` is already page aligned. + */ +inline size_t make_offset_page_aligned(size_t offset) noexcept +{ + const size_t page_size_ = page_size(); + // Use integer division to round down to the nearest page alignment. + return offset / page_size_ * page_size_; +} + +} // namespace mio + +#endif // MIO_PAGE_HEADER +/* Copyright 2017 https://github.com/mandreyel + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of this + * software and associated documentation files (the "Software"), to deal in the Software + * without restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be included in all copies + * or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, + * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE + * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef MIO_SHARED_MMAP_HEADER +#define MIO_SHARED_MMAP_HEADER + +// #include "mio/mmap.hpp" + + +#include // std::error_code +#include // std::shared_ptr + +namespace mio { + +/** + * Exposes (nearly) the same interface as `basic_mmap`, but endowes it with + * `std::shared_ptr` semantics. + * + * This is not the default behaviour of `basic_mmap` to avoid allocating on the heap if + * shared semantics are not required. + */ +template< + access_mode AccessMode, + typename ByteT +> class basic_shared_mmap +{ + using impl_type = basic_mmap; + std::shared_ptr pimpl_; + +public: + using value_type = typename impl_type::value_type; + using size_type = typename impl_type::size_type; + using reference = typename impl_type::reference; + using const_reference = typename impl_type::const_reference; + using pointer = typename impl_type::pointer; + using const_pointer = typename impl_type::const_pointer; + using difference_type = typename impl_type::difference_type; + using iterator = typename impl_type::iterator; + using const_iterator = typename impl_type::const_iterator; + using reverse_iterator = typename impl_type::reverse_iterator; + using const_reverse_iterator = typename impl_type::const_reverse_iterator; + using iterator_category = typename impl_type::iterator_category; + using handle_type = typename impl_type::handle_type; + using mmap_type = impl_type; + + basic_shared_mmap() = default; + basic_shared_mmap(const basic_shared_mmap&) = default; + basic_shared_mmap& operator=(const basic_shared_mmap&) = default; + basic_shared_mmap(basic_shared_mmap&&) = default; + basic_shared_mmap& operator=(basic_shared_mmap&&) = default; + + /** Takes ownership of an existing mmap object. */ + basic_shared_mmap(mmap_type&& mmap) + : pimpl_(std::make_shared(std::move(mmap))) + {} + + /** Takes ownership of an existing mmap object. */ + basic_shared_mmap& operator=(mmap_type&& mmap) + { + pimpl_ = std::make_shared(std::move(mmap)); + return *this; + } + + /** Initializes this object with an already established shared mmap. */ + basic_shared_mmap(std::shared_ptr mmap) : pimpl_(std::move(mmap)) {} + + /** Initializes this object with an already established shared mmap. */ + basic_shared_mmap& operator=(std::shared_ptr mmap) + { + pimpl_ = std::move(mmap); + return *this; + } + +#ifdef __cpp_exceptions + /** + * The same as invoking the `map` function, except any error that may occur + * while establishing the mapping is wrapped in a `std::system_error` and is + * thrown. + */ + template + basic_shared_mmap(const String& path, const size_type offset = 0, const size_type length = map_entire_file) + { + std::error_code error; + map(path, offset, length, error); + if(error) { throw std::system_error(error); } + } + + /** + * The same as invoking the `map` function, except any error that may occur + * while establishing the mapping is wrapped in a `std::system_error` and is + * thrown. + */ + basic_shared_mmap(const handle_type handle, const size_type offset = 0, const size_type length = map_entire_file) + { + std::error_code error; + map(handle, offset, length, error); + if(error) { throw std::system_error(error); } + } +#endif // __cpp_exceptions + + /** + * If this is a read-write mapping and the last reference to the mapping, + * the destructor invokes sync. Regardless of the access mode, unmap is + * invoked as a final step. + */ + ~basic_shared_mmap() = default; + + /** Returns the underlying `std::shared_ptr` instance that holds the mmap. */ + std::shared_ptr get_shared_ptr() { return pimpl_; } + + /** + * On UNIX systems 'file_handle' and 'mapping_handle' are the same. On Windows, + * however, a mapped region of a file gets its own handle, which is returned by + * 'mapping_handle'. + */ + handle_type file_handle() const noexcept + { + return pimpl_ ? pimpl_->file_handle() : invalid_handle; + } + + handle_type mapping_handle() const noexcept + { + return pimpl_ ? pimpl_->mapping_handle() : invalid_handle; + } + + /** Returns whether a valid memory mapping has been created. */ + bool is_open() const noexcept { return pimpl_ && pimpl_->is_open(); } + + /** + * Returns true if no mapping was established, that is, conceptually the + * same as though the length that was mapped was 0. This function is + * provided so that this class has Container semantics. + */ + bool empty() const noexcept { return !pimpl_ || pimpl_->empty(); } + + /** + * `size` and `length` both return the logical length, i.e. the number of bytes + * user requested to be mapped, while `mapped_length` returns the actual number of + * bytes that were mapped which is a multiple of the underlying operating system's + * page allocation granularity. + */ + size_type size() const noexcept { return pimpl_ ? pimpl_->length() : 0; } + size_type length() const noexcept { return pimpl_ ? pimpl_->length() : 0; } + size_type mapped_length() const noexcept + { + return pimpl_ ? pimpl_->mapped_length() : 0; + } + + /** + * Returns the offset, relative to the file's start, at which the mapping was + * requested to be created. + */ + size_type offset() const noexcept { return pimpl_ ? pimpl_->offset() : 0; } + + /** + * Returns a pointer to the first requested byte, or `nullptr` if no memory mapping + * exists. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > pointer data() noexcept { return pimpl_->data(); } + const_pointer data() const noexcept { return pimpl_ ? pimpl_->data() : nullptr; } + + /** + * Returns an iterator to the first requested byte, if a valid memory mapping + * exists, otherwise this function call is undefined behaviour. + */ + iterator begin() noexcept { return pimpl_->begin(); } + const_iterator begin() const noexcept { return pimpl_->begin(); } + const_iterator cbegin() const noexcept { return pimpl_->cbegin(); } + + /** + * Returns an iterator one past the last requested byte, if a valid memory mapping + * exists, otherwise this function call is undefined behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > iterator end() noexcept { return pimpl_->end(); } + const_iterator end() const noexcept { return pimpl_->end(); } + const_iterator cend() const noexcept { return pimpl_->cend(); } + + /** + * Returns a reverse iterator to the last memory mapped byte, if a valid + * memory mapping exists, otherwise this function call is undefined + * behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > reverse_iterator rbegin() noexcept { return pimpl_->rbegin(); } + const_reverse_iterator rbegin() const noexcept { return pimpl_->rbegin(); } + const_reverse_iterator crbegin() const noexcept { return pimpl_->crbegin(); } + + /** + * Returns a reverse iterator past the first mapped byte, if a valid memory + * mapping exists, otherwise this function call is undefined behaviour. + */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > reverse_iterator rend() noexcept { return pimpl_->rend(); } + const_reverse_iterator rend() const noexcept { return pimpl_->rend(); } + const_reverse_iterator crend() const noexcept { return pimpl_->crend(); } + + /** + * Returns a reference to the `i`th byte from the first requested byte (as returned + * by `data`). If this is invoked when no valid memory mapping has been created + * prior to this call, undefined behaviour ensues. + */ + reference operator[](const size_type i) noexcept { return (*pimpl_)[i]; } + const_reference operator[](const size_type i) const noexcept { return (*pimpl_)[i]; } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `path`, which must be a path to an existing file, is used to retrieve a file + * handle (which is closed when the object destructs or `unmap` is called), which is + * then used to memory map the requested region. Upon failure, `error` is set to + * indicate the reason and the object remains in an unmapped state. + * + * `offset` is the number of bytes, relative to the start of the file, where the + * mapping should begin. When specifying it, there is no need to worry about + * providing a value that is aligned with the operating system's page allocation + * granularity. This is adjusted by the implementation such that the first requested + * byte (as returned by `data` or `begin`), so long as `offset` is valid, will be at + * `offset` from the start of the file. + * + * `length` is the number of bytes to map. It may be `map_entire_file`, in which + * case a mapping of the entire file is created. + */ + template + void map(const String& path, const size_type offset, + const size_type length, std::error_code& error) + { + map_impl(path, offset, length, error); + } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `path`, which must be a path to an existing file, is used to retrieve a file + * handle (which is closed when the object destructs or `unmap` is called), which is + * then used to memory map the requested region. Upon failure, `error` is set to + * indicate the reason and the object remains in an unmapped state. + * + * The entire file is mapped. + */ + template + void map(const String& path, std::error_code& error) + { + map_impl(path, 0, map_entire_file, error); + } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `handle`, which must be a valid file handle, which is used to memory map the + * requested region. Upon failure, `error` is set to indicate the reason and the + * object remains in an unmapped state. + * + * `offset` is the number of bytes, relative to the start of the file, where the + * mapping should begin. When specifying it, there is no need to worry about + * providing a value that is aligned with the operating system's page allocation + * granularity. This is adjusted by the implementation such that the first requested + * byte (as returned by `data` or `begin`), so long as `offset` is valid, will be at + * `offset` from the start of the file. + * + * `length` is the number of bytes to map. It may be `map_entire_file`, in which + * case a mapping of the entire file is created. + */ + void map(const handle_type handle, const size_type offset, + const size_type length, std::error_code& error) + { + map_impl(handle, offset, length, error); + } + + /** + * Establishes a memory mapping with AccessMode. If the mapping is unsuccesful, the + * reason is reported via `error` and the object remains in a state as if this + * function hadn't been called. + * + * `handle`, which must be a valid file handle, which is used to memory map the + * requested region. Upon failure, `error` is set to indicate the reason and the + * object remains in an unmapped state. + * + * The entire file is mapped. + */ + void map(const handle_type handle, std::error_code& error) + { + map_impl(handle, 0, map_entire_file, error); + } + + /** + * If a valid memory mapping has been created prior to this call, this call + * instructs the kernel to unmap the memory region and disassociate this object + * from the file. + * + * The file handle associated with the file that is mapped is only closed if the + * mapping was created using a file path. If, on the other hand, an existing + * file handle was used to create the mapping, the file handle is not closed. + */ + void unmap() { if(pimpl_) pimpl_->unmap(); } + + void swap(basic_shared_mmap& other) { pimpl_.swap(other.pimpl_); } + + /** Flushes the memory mapped page to disk. Errors are reported via `error`. */ + template< + access_mode A = AccessMode, + typename = typename std::enable_if::type + > void sync(std::error_code& error) { if(pimpl_) pimpl_->sync(error); } + + /** All operators compare the underlying `basic_mmap`'s addresses. */ + + friend bool operator==(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return a.pimpl_ == b.pimpl_; + } + + friend bool operator!=(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return !(a == b); + } + + friend bool operator<(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return a.pimpl_ < b.pimpl_; + } + + friend bool operator<=(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return a.pimpl_ <= b.pimpl_; + } + + friend bool operator>(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return a.pimpl_ > b.pimpl_; + } + + friend bool operator>=(const basic_shared_mmap& a, const basic_shared_mmap& b) + { + return a.pimpl_ >= b.pimpl_; + } + +private: + template + void map_impl(const MappingToken& token, const size_type offset, + const size_type length, std::error_code& error) + { + if(!pimpl_) + { + mmap_type mmap = make_mmap(token, offset, length, error); + if(error) { return; } + pimpl_ = std::make_shared(std::move(mmap)); + } + else + { + pimpl_->map(token, offset, length, error); + } + } +}; + +/** + * This is the basis for all read-only mmap objects and should be preferred over + * directly using basic_shared_mmap. + */ +template +using basic_shared_mmap_source = basic_shared_mmap; + +/** + * This is the basis for all read-write mmap objects and should be preferred over + * directly using basic_shared_mmap. + */ +template +using basic_shared_mmap_sink = basic_shared_mmap; + +/** + * These aliases cover the most common use cases, both representing a raw byte stream + * (either with a char or an unsigned char/uint8_t). + */ +using shared_mmap_source = basic_shared_mmap_source; +using shared_ummap_source = basic_shared_mmap_source; + +using shared_mmap_sink = basic_shared_mmap_sink; +using shared_ummap_sink = basic_shared_mmap_sink; + +} // namespace mio + +#endif // MIO_SHARED_MMAP_HEADER