diff options
Diffstat (limited to 'src/alloc/alloc_mmap/mmap_mem.cpp')
-rw-r--r-- | src/alloc/alloc_mmap/mmap_mem.cpp | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/src/alloc/alloc_mmap/mmap_mem.cpp b/src/alloc/alloc_mmap/mmap_mem.cpp new file mode 100644 index 000000000..e9ea17a53 --- /dev/null +++ b/src/alloc/alloc_mmap/mmap_mem.cpp @@ -0,0 +1,128 @@ +/************************************************* +* Memory Mapping Allocator Source File * +* (C) 1999-2007 Jack Lloyd * +*************************************************/ + +#include <botan/mmap_mem.h> +#include <cstring> + +#ifndef _XOPEN_SOURCE + #define _XOPEN_SOURCE 500 +#endif + +#ifndef _XOPEN_SOURCE_EXTENDED + #define _XOPEN_SOURCE_EXTENDED 1 +#endif + +#include <sys/types.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <unistd.h> +#include <stdlib.h> +#include <fcntl.h> + +#ifndef MAP_FAILED + #define MAP_FAILED -1 +#endif + +namespace Botan { + +namespace { + +/************************************************* +* MemoryMapping_Allocator Exception * +*************************************************/ +class MemoryMapping_Failed : public Exception + { + public: + MemoryMapping_Failed(const std::string& msg) : + Exception("MemoryMapping_Allocator: " + msg) {} + }; + +} + +/************************************************* +* Memory Map a File into Memory * +*************************************************/ +void* MemoryMapping_Allocator::alloc_block(u32bit n) + { + class TemporaryFile + { + public: + int get_fd() const { return fd; } + const std::string path() const { return filepath; } + + TemporaryFile(const std::string& base) + { + const std::string path = base + "XXXXXX"; + + filepath = new char[path.length() + 1]; + std::strcpy(filepath, path.c_str()); + + mode_t old_umask = ::umask(077); + fd = ::mkstemp(filepath); + ::umask(old_umask); + } + + ~TemporaryFile() + { + delete[] filepath; + if(fd != -1 && ::close(fd) == -1) + throw MemoryMapping_Failed("Could not close file"); + } + private: + int fd; + char* filepath; + }; + + TemporaryFile file("/tmp/botan_"); + + if(file.get_fd() == -1) + throw MemoryMapping_Failed("Could not create file"); + + if(::unlink(file.path().c_str())) + throw MemoryMapping_Failed("Could not unlink file '" + file.path() + "'"); + + ::lseek(file.get_fd(), n-1, SEEK_SET); + if(::write(file.get_fd(), "\0", 1) != 1) + throw MemoryMapping_Failed("Could not write to file"); + +#ifndef MAP_NOSYNC + #define MAP_NOSYNC 0 +#endif + + void* ptr = ::mmap(0, n, + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_NOSYNC, + file.get_fd(), 0); + + if(ptr == static_cast<void*>(MAP_FAILED)) + throw MemoryMapping_Failed("Could not map file"); + + return ptr; + } + +/************************************************* +* Remove a Memory Mapping * +*************************************************/ +void MemoryMapping_Allocator::dealloc_block(void* ptr, u32bit n) + { + if(ptr == 0) + return; + + const byte PATTERNS[] = { 0x00, 0xFF, 0xAA, 0x55, 0x73, 0x8C, 0x5F, 0xA0, + 0x6E, 0x91, 0x30, 0xCF, 0xD3, 0x2C, 0xAC, 0x00 }; + + for(u32bit j = 0; j != sizeof(PATTERNS); j++) + { + std::memset(ptr, PATTERNS[j], n); + + if(::msync(ptr, n, MS_SYNC)) + throw MemoryMapping_Failed("Sync operation failed"); + } + + if(::munmap(ptr, n)) + throw MemoryMapping_Failed("Could not unmap file"); + } + +} |