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/****************************************************************************
* *
* OpenNI 1.x Alpha *
* Copyright (C) 2011 PrimeSense Ltd. *
* *
* This file is part of OpenNI. *
* *
* OpenNI 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 3 of the License, or *
* (at your option) any later version. *
* *
* OpenNI 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 OpenNI. If not, see <http://www.gnu.org/licenses/>. *
* *
****************************************************************************/
//---------------------------------------------------------------------------
// Includes
//---------------------------------------------------------------------------
#include <XnOS.h>
#include <errno.h>
#if (XN_PLATFORM == XN_PLATFORM_MACOSX || XN_PLATFORM == XN_PLATFORM_ANDROID_ARM)
#include <sys/wait.h>
#else
#include <wait.h>
#endif
#include <XnLog.h>
//---------------------------------------------------------------------------
// Code
//---------------------------------------------------------------------------
XN_C_API XnStatus xnOSGetCurrentProcessID(XN_PROCESS_ID* pProcID)
{
// Validate output pointer
XN_VALIDATE_OUTPUT_PTR(pProcID);
// Get the current process id
*pProcID = getpid();
// All is good...
return (XN_STATUS_OK);
}
XN_C_API XnStatus xnOSCreateProcess(const XnChar* strExecutable, XnUInt32 nArgs, const XnChar** pstrArgs, XN_PROCESS_ID* pProcID)
{
XnStatus nRetVal = XN_STATUS_OK;
// NOTE: execv, for some weird reason, accepts the arguments as non-const strings, but in the documentation
// it is explicitly stated that it does not change anything, so we can just use const_cast for it.
XnChar* astrArgs[100];
if (nArgs > 98)
{
xnLogWarning(XN_MASK_OS, "Too many arguments!");
return XN_STATUS_OS_PROCESS_CREATION_FAILED;
}
astrArgs[0] = const_cast<char*>(strExecutable);
for (XnUInt i = 0; i < nArgs; ++i)
{
astrArgs[i+1] = const_cast<char*>(pstrArgs[i]);
}
astrArgs[nArgs+1] = NULL;
pid_t child_pid = fork();
if (child_pid == -1) // fail
{
xnLogWarning(XN_MASK_OS, "Failed to start process! fork() error code is %d.", errno);
return XN_STATUS_OS_PROCESS_CREATION_FAILED;
}
else if (child_pid == 0) // child process
{
// fork again
// we want our process to be totally detached from creator process. To do so, we fork() twice, so that the creator process
// is terminated, and the new process becomes the child of init.
pid_t grandchild_pid = fork();
if (grandchild_pid == -1)
{
exit(XN_STATUS_OS_PROCESS_CREATION_FAILED);
}
else if (grandchild_pid == 0) // grandchild process
{
// close standard streams (this is a background process)
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
// detach it from current process (so it will keep running, even if process is terminated)
setsid();
// load the executable
if (-1 == execv(strExecutable, astrArgs))
{
xnLogWarning(XN_MASK_OS, "Failed to start process! execv() error code is %d.", errno);
return XN_STATUS_OS_PROCESS_CREATION_FAILED;
}
}
else // child process
{
_exit(XN_STATUS_OK);
}
}
else // parent process
{
// wait for the child process (the one creating the grandchild process), and make sure it succeeded)
int status = 0;
waitpid(child_pid, &status, 0);
if (status != 0)
{
return XN_STATUS_OS_PROCESS_CREATION_FAILED;
}
// we have no way to get the grandchild pid
*pProcID = 0;
}
return (XN_STATUS_OK);
}
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