ClickHouse/base/base/mremap.cpp

33 lines
734 B
C++

#include <base/mremap.h>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <errno.h>
void * mremap_fallback(
void * old_address, size_t old_size, size_t new_size, int flags, int mmap_prot, int mmap_flags, int mmap_fd, off_t mmap_offset)
{
/// No actual shrink
if (new_size < old_size)
return old_address;
if (!(flags & MREMAP_MAYMOVE))
{
errno = ENOMEM;
return MAP_FAILED;
}
void * new_address = mmap(nullptr, new_size, mmap_prot, mmap_flags, mmap_fd, mmap_offset);
if (MAP_FAILED == new_address)
return MAP_FAILED;
memcpy(new_address, old_address, old_size);
if (munmap(old_address, old_size))
abort();
return new_address;
}