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/* Copyright (c) 2013 Stanislaw Halik <sthalik@misaki.pl>
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*/
#include "shm.h"
#if defined _WIN32
#include <cstring>
#include <cstdio>
#include <accctrl.h>
#include <aclapi.h>
#if !defined __WINE__
# include <QDebug>
# define warn(str, ...) (qDebug() << "shm:" str ": " << __VA_ARGS__)
#else
# define warn(str, ...) (void)0
#endif
shm_wrapper::shm_wrapper(const char* shm_name, const char* mutex_name, int map_size)
{
if (mutex_name == nullptr)
mutex = nullptr;
else
{
mutex = CreateMutexA(nullptr, false, mutex_name);
if (!mutex)
{
warn("CreateMutexA", (int) GetLastError());
return;
}
}
mapped_file = CreateFileMappingA(
INVALID_HANDLE_VALUE,
nullptr,
PAGE_READWRITE,
0,
map_size,
shm_name);
if (!mapped_file)
{
warn("CreateFileMappingA", (int) GetLastError());
return;
}
mem = MapViewOfFile(mapped_file,
FILE_MAP_WRITE,
0,
0,
map_size);
if (!mem)
warn("MapViewOfFile:", (int) GetLastError());
}
shm_wrapper::~shm_wrapper()
{
if (mem && !UnmapViewOfFile(mem))
goto fail;
if (mapped_file && !CloseHandle(mapped_file))
goto fail;
if (mutex && !CloseHandle(mutex))
goto fail;
return;
fail:
warn("failed to close mapping", (int) GetLastError());
}
bool shm_wrapper::lock()
{
if (mutex)
return WaitForSingleObject(mutex, INFINITE) == WAIT_OBJECT_0;
else
return false;
}
bool shm_wrapper::unlock()
{
if (mutex)
return ReleaseMutex(mutex);
else
return false;
}
#else
#include <limits.h>
#pragma GCC diagnostic ignored "-Wunused-result"
shm_wrapper::shm_wrapper(const char *shm_name, const char* /*mutex_name*/, int map_size) : size(map_size)
{
char filename[PATH_MAX+2] {};
strcpy(filename, "/");
strcat(filename, shm_name);
fd = shm_open(filename, O_RDWR | O_CREAT, 0600);
(void) ftruncate(fd, map_size);
mem = mmap(NULL, map_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, (off_t)0);
}
shm_wrapper::~shm_wrapper()
{
(void) munmap(mem, size);
(void) close(fd);
}
bool shm_wrapper::lock()
{
return flock(fd, LOCK_EX) == 0;
}
bool shm_wrapper::unlock()
{
return flock(fd, LOCK_UN) == 0;
}
#endif
bool shm_wrapper::success()
{
#ifndef _WIN32
return mem != (void*) -1;
#else
return mem != nullptr;
#endif
}
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