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XrdOucSid.cc
Go to the documentation of this file.
/******************************************************************************/
/* */
/* X r d O u c S i d . c c */
/* */
/* (c) 2013 by the Board of Trustees of the Leland Stanford, Jr., University */
/* All Rights Reserved */
/* Produced by Andrew Hanushevsky for Stanford University under contract */
/* DE-AC02-76-SFO0515 with the Department of Energy */
/* */
/* This file is part of the XRootD software suite. */
/* */
/* XRootD 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. */
/* */
/* XRootD 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 XRootD in a file called COPYING.LESSER (LGPL license) and file */
/* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
/* */
/* The copyright holder's institutional names and contributor's names may not */
/* be used to endorse or promote products derived from this software without */
/* specific prior written permission of the institution or contributor. */
/******************************************************************************/
#include "XrdOuc/XrdOucSid.hh"
/******************************************************************************/
/* C o n s t r u c t o r */
/******************************************************************************/
XrdOucSid::XrdOucSid(int numSid, bool mtproof, XrdOucSid *glblSid)
{
// Set obvious values
//
sidLock = mtproof;
globalSid = glblSid;
// Calculate actual values
//
sidSize = (numSid / 8) + ((numSid % 8 ? 1 : 0) * 8);
sidMax = sidSize * 8;
sidFree = 0;
// Allocate a sid table for the number we want
//
sidVec = (unsigned char *)malloc(sidSize);
memset(sidVec, 255, sidSize);
}
/******************************************************************************/
/* D e s t r u c t o r */
/******************************************************************************/
XrdOucSid::~XrdOucSid()
{
if (sidVec) free(sidVec);
}
/******************************************************************************/
/* O b t a i n */
/******************************************************************************/
bool XrdOucSid::Obtain(XrdOucSid::theSid *sidP)
{
// 0000 0001 0010 0011 0100 0101 0110 0111
static const // 1000 1001 1010 1011 1100 1101 1110 1111
unsigned char mask[] = {0x00,0x11,0x22,0x11,0x44,0x11,0x22,0x11,
0x88,0x11,0x22,0x11,0x44,0x11,0x22,0x11};
bool aOK = true;
// Lock if need be
//
if (sidLock) sidMutex.Lock();
// Realign the vector
//
while(sidFree < sidSize && sidVec[sidFree] == 0x00) sidFree++;
// Allocate a local free sid if we actually have one free. Otherwise, try to
// allocate one from the global sid table.
//
if (sidFree < sidSize)
{int sidMask, sidNum, sidByte = sidVec[sidFree] & 0xff;
if (sidByte & 0x0f)
{sidMask = mask[sidByte & 0x0f] & 0x0f;
sidNum = (sidMask > 4 ? 3 : sidMask>>1);
} else {
sidMask = mask[sidByte >> 4] & 0xf0;
sidNum = (sidMask > 64 ? 7 : (sidMask>>5) + 4);
}
sidVec[sidFree] &= ~sidMask;
sidP->sidS = (sidFree * 8) + sidNum;
} else if (globalSid)
{aOK = globalSid->Obtain(sidP);
sidP->sidS += sidMax;
} else aOK = false;
// Unlock if locked and return result
//
if (sidLock) sidMutex.UnLock();
return aOK;
}
/******************************************************************************/
/* R e l e a s e */
/******************************************************************************/
bool XrdOucSid::Release(XrdOucSid::theSid *sidP)
{
static const // 0 1 2 3 4 5 6 7
unsigned char mask[] = {0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
bool aOK = true;
// Lock if need be
//
if (sidLock) sidMutex.Lock();
// If this is a local sid, then handle it locally. Otherwise, try releasing
// using the global sid pool.
//
if (sidP->sidS < sidMax)
{int sidIdx = (sidP->sidS)>>3;
sidVec[sidIdx] |= mask[(sidP->sidS)%8];
if (sidIdx < sidFree) sidFree = sidIdx;
} else if (globalSid)
{short gSid = sidP->sidS - sidMax;
aOK = globalSid->Release((theSid *)&gSid);
} else aOK = false;
// Unlock if locked and return result
//
if (sidLock) sidMutex.UnLock();
return aOK;
}
/******************************************************************************/
/* R e s e t */
/******************************************************************************/
void XrdOucSid::Reset()
{
if (sidLock) sidMutex.Lock();
if (sidVec) memset(sidVec, 0xff, sidSize);
if (sidLock) sidMutex.UnLock();
}
XrdOucSid.hh
XrdOucSid::XrdOucSid
XrdOucSid(int numSid=256, bool mtproof=true, XrdOucSid *glblSid=0)
Definition XrdOucSid.cc:37
XrdOucSid::Reset
void Reset()
Definition XrdOucSid.cc:147
XrdOucSid::Obtain
bool Obtain(theSid *sidP)
Definition XrdOucSid.cc:70
XrdOucSid::~XrdOucSid
~XrdOucSid()
Definition XrdOucSid.cc:61
XrdOucSid::Release
bool Release(theSid *sidP)
Definition XrdOucSid.cc:115
XrdOucSid::theSid
The type to pass to Obtain(). Simply cast the char[2] to (theSid *).
Definition XrdOucSid.hh:53