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/*******************************************************************************
Copyright(c) 2022 Ludovic Pollet. All rights reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License version 2 as published by the Free Software Foundation.
This 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*******************************************************************************/
extern "C" {
// Load shm_open_anon but force it to have static symbol only
static int shm_open_anon(void);
#include "../libs/indicore/shm_open_anon.c"
}
#include <system_error>
#include "SharedBuffer.h"
#ifdef __linux__
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <linux/unistd.h>
#endif
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>
SharedBuffer::SharedBuffer()
{
fd = -1;
size = 0;
}
SharedBuffer::~SharedBuffer()
{
release();
}
void SharedBuffer::attach(int fd)
{
release();
this->fd = fd;
if (fd == -1)
{
size = 0;
return;
}
struct stat sb;
if (fstat(fd, &sb) == -1)
{
int e = errno;
throw std::system_error(e, std::generic_category(), "Unable to stat buffer");
}
size = sb.st_size;
}
void SharedBuffer::release()
{
if (fd != -1)
{
close(fd);
fd = -1;
}
size = 0;
}
int SharedBuffer::getFd() const
{
if (fd == -1)
{
throw std::runtime_error("SharedBuffer is not allocated");
}
return fd;
}
void SharedBuffer::write(const void * data, ssize_t offset, ssize_t writeSize)
{
if (writeSize == 0)
{
return;
}
if (size < offset + writeSize)
{
throw std::runtime_error("Attempt to write beyond past");
}
void * mmapped = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (mmapped == MAP_FAILED)
{
perror("mmap");
throw std::runtime_error("Mmap failed");
}
memcpy((void*)((char*)mmapped + offset), data, writeSize);
if (munmap(mmapped, size) == -1)
{
perror("munmap");
throw std::runtime_error("Munmap failed");
}
}
void SharedBuffer::allocate(ssize_t nsize)
{
release();
fd = shm_open_anon();
if (fd == -1)
{
throw std::system_error(errno, std::generic_category(), "memfd_create");
}
int ret = ftruncate(fd, nsize);
if (ret == -1)
{
throw std::system_error(errno, std::generic_category(), "memfd_create");
}
size = nsize;
}
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