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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"
#include <QDebug>
#if defined(_WIN32)
#include <cstring>
#include <stdio.h>
#include <accctrl.h>
#include <aclapi.h>
struct secattr
{
bool success;
SECURITY_DESCRIPTOR* pSD;
SECURITY_ATTRIBUTES attrs;
PSID pEveryoneSID;
PACL pACL;
void cleanup()
{
if (pEveryoneSID)
FreeSid(pEveryoneSID);
if (pACL)
LocalFree(pACL);
if (pSD)
LocalFree(pSD);
success = false;
pSD = nullptr;
pEveryoneSID = nullptr;
pACL = nullptr;
}
secattr(DWORD perms) : success(true), pSD(nullptr), pEveryoneSID(nullptr), pACL(nullptr)
{
SID_IDENTIFIER_AUTHORITY SIDAuthWorld = SECURITY_WORLD_SID_AUTHORITY;
EXPLICIT_ACCESS ea;
if(!AllocateAndInitializeSid(&SIDAuthWorld, 1,
SECURITY_WORLD_RID,
0, 0, 0, 0, 0, 0, 0,
&pEveryoneSID))
{
fprintf(stderr, "AllocateAndInitializeSid: %d\n", (int) GetLastError());
goto cleanup;
}
memset(&ea, 0, sizeof(ea));
ea.grfAccessPermissions = perms;
ea.grfAccessMode = SET_ACCESS;
ea.grfInheritance = NO_INHERITANCE;
ea.Trustee.TrusteeForm = TRUSTEE_IS_SID;
ea.Trustee.TrusteeType = TRUSTEE_IS_WELL_KNOWN_GROUP;
ea.Trustee.ptstrName = (LPTSTR) pEveryoneSID;
if (SetEntriesInAcl(1, &ea, NULL, &pACL) != ERROR_SUCCESS)
{
fprintf(stderr, "SetEntriesInAcl: %d\n", (int) GetLastError());
goto cleanup;
}
pSD = (SECURITY_DESCRIPTOR*) LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
if (pSD == nullptr)
{
fprintf(stderr, "LocalAlloc: %d\n", (int) GetLastError());
goto cleanup;
}
if (!InitializeSecurityDescriptor(pSD,
SECURITY_DESCRIPTOR_REVISION))
{
fprintf(stderr, "InitializeSecurityDescriptor: %d\n", (int) GetLastError());
goto cleanup;
}
if (!SetSecurityDescriptorDacl(pSD,
TRUE,
pACL,
FALSE))
{
fprintf(stderr, "SetSecurityDescriptorDacl: %d\n", (int) GetLastError());
goto cleanup;
}
attrs.bInheritHandle = false;
attrs.lpSecurityDescriptor = pSD;
attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
return;
cleanup:
cleanup();
}
~secattr()
{
cleanup();
}
};
PortableLockedShm::PortableLockedShm(const char* shmName, const char* mutexName, int mapSize)
{
secattr sa(GENERIC_ALL|SYNCHRONIZE);
hMutex = CreateMutexA(sa.success ? &sa.attrs : nullptr, false, mutexName);
if (!hMutex)
{
qDebug() << "CreateMutexA:" << (int) GetLastError();
return;
}
hMapFile = CreateFileMappingA(
INVALID_HANDLE_VALUE,
sa.success ? &sa.attrs : nullptr,
PAGE_READWRITE,
0,
mapSize,
shmName);
if (!hMapFile)
{
qDebug() << "CreateFileMappingA:", (int) GetLastError();
return;
}
mem = MapViewOfFile(hMapFile,
FILE_MAP_WRITE,
0,
0,
mapSize);
if (!mem)
qDebug() << "MapViewOfFile:" << (int) GetLastError();
}
PortableLockedShm::~PortableLockedShm()
{
if(!UnmapViewOfFile(mem))
goto fail;
if (!CloseHandle(hMapFile))
goto fail;
if (!CloseHandle(hMutex))
goto fail;
return;
fail:
qDebug() << "failed to close mapping";
}
bool PortableLockedShm::lock()
{
return WaitForSingleObject(hMutex, INFINITE) == WAIT_OBJECT_0;
}
bool PortableLockedShm::unlock()
{
return ReleaseMutex(hMutex);
}
#else
#include <limits.h>
#pragma GCC diagnostic ignored "-Wunused-result"
PortableLockedShm::PortableLockedShm(const char *shmName, const char* /*mutexName*/, int mapSize) : size(mapSize)
{
char filename[PATH_MAX+2] {};
strcpy(filename, "/");
strcat(filename, shmName);
fd = shm_open(filename, O_RDWR | O_CREAT, 0600);
(void) ftruncate(fd, mapSize);
mem = mmap(NULL, mapSize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, (off_t)0);
}
PortableLockedShm::~PortableLockedShm()
{
(void) munmap(mem, size);
(void) close(fd);
}
bool PortableLockedShm::lock()
{
return flock(fd, LOCK_EX) == 0;
}
bool PortableLockedShm::unlock()
{
return flock(fd, LOCK_UN) == 0;
}
#endif
bool PortableLockedShm::success()
{
#ifndef _WIN32
return mem != (void*) -1;
#else
return mem != NULL;
#endif
}
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