| /* Allocate a memory region shared across processes. |
| Copyright (C) 2017-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <stddef.h> |
| #include <support/support.h> |
| #include <support/xunistd.h> |
| #include <sys/mman.h> |
| |
| /* Header for the allocation. It contains the size of the allocation |
| for subsequent unmapping. */ |
| struct header |
| { |
| size_t total_size; |
| char data[] __attribute__ ((aligned (__alignof__ (max_align_t)))); |
| }; |
| |
| void * |
| support_shared_allocate (size_t size) |
| { |
| size_t total_size = size + offsetof (struct header, data); |
| if (total_size < size) |
| { |
| errno = ENOMEM; |
| oom_error (__func__, size); |
| return NULL; |
| } |
| else |
| { |
| struct header *result = xmmap (NULL, total_size, PROT_READ | PROT_WRITE, |
| MAP_ANONYMOUS | MAP_SHARED, -1); |
| result->total_size = total_size; |
| return &result->data; |
| } |
| } |
| |
| void |
| support_shared_free (void *data) |
| { |
| struct header *header = data - offsetof (struct header, data); |
| xmunmap (header, header->total_size); |
| } |