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TLockPath.cxx
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1// @(#)root/proof:$Id$
2// Author: G. Ganis, Oct 2011
3
4/*************************************************************************
5 * Copyright (C) 1995-2005, Rene Brun and Fons Rademakers. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12/** \class TLockPath
13\ingroup proofkernel
14
15Path locking class allowing shared and exclusive locks
16
17*/
18
19#include "TLockPath.h"
20#include "TSystem.h"
21#if defined(R__WIN32) && !defined(R__WINGCC)
22#include <io.h>
23#define lseek _lseek
24#define close _close
25#define open _open
26#define O_CREAT _O_CREAT
27#define O_RDWR _O_RDWR
28#else
29#include <sys/file.h>
30#endif
31
32////////////////////////////////////////////////////////////////////////////////
33/// Locks the directory. Waits if lock is hold by an other process.
34/// Returns 0 on success, -1 in case of error.
35
36TLockPath::TLockPath(const char *path) : fName(path), fLockId(-1)
37{
38 // Work with full names
40 Warning("TLockPath", "problems expanding path '%s'", fName.Data());
41}
42
44{
45 const char *pname = GetName();
46
47 if (gSystem->AccessPathName(pname))
48 fLockId = open(pname, O_CREAT | O_RDWR, 0644);
49 else
50 fLockId = open(pname, O_RDWR);
51
52 if (fLockId == -1) {
53 SysError("Lock", "cannot open lock file %s", pname);
54 return -1;
55 }
56
57 if (gDebug > 1)
58 Info("Lock", "%d: locking file %s ...", gSystem->GetPid(), pname);
59 // lock the file
60#if !defined(R__WIN32) && !defined(R__WINGCC)
61 int op = (shared) ? LOCK_SH : LOCK_EX ;
62 if (flock(fLockId, op) == -1) {
63 SysError("Lock", "error locking %s", pname);
65 fLockId = -1;
66 return -1;
67 }
68#endif
69
70 if (gDebug > 1)
71 Info("Lock", "%d: file %s locked", gSystem->GetPid(), pname);
72
73 return 0;
74}
75
76////////////////////////////////////////////////////////////////////////////////
77/// Unlock the directory. Returns 0 in case of success,
78/// -1 in case of error.
79
81{
82 if (!IsLocked())
83 return 0;
84
85 if (gDebug > 1)
86 Info("Unlock", "%d: unlocking file %s ...", gSystem->GetPid(), GetName());
87 // unlock the file
88 lseek(fLockId, 0, SEEK_SET);
89#if !defined(R__WIN32) && !defined(R__WINGCC)
90 if (flock(fLockId, LOCK_UN) == -1) {
91 SysError("Unlock", "error unlocking %s", GetName());
93 fLockId = -1;
94 return -1;
95 }
96#endif
97
98 if (gDebug > 1)
99 Info("Unlock", "%d: file %s unlocked", gSystem->GetPid(), GetName());
100
101 close(fLockId);
102 fLockId = -1;
103
104 return 0;
105}
Int_t gDebug
Definition: TROOT.cxx:585
R__EXTERN TSystem * gSystem
Definition: TSystem.h:559
TLockPath(const char *path="")
Locks the directory.
Definition: TLockPath.cxx:36
const char * GetName() const
Returns name of object.
Definition: TLockPath.h:35
Int_t fLockId
Definition: TLockPath.h:29
Int_t Lock(Bool_t shared=kFALSE)
Definition: TLockPath.cxx:43
Bool_t IsLocked() const
Definition: TLockPath.h:41
Int_t Unlock()
Unlock the directory.
Definition: TLockPath.cxx:80
TString fName
Definition: TLockPath.h:28
virtual void SysError(const char *method, const char *msgfmt,...) const
Issue system error message.
Definition: TObject.cxx:907
virtual void Warning(const char *method, const char *msgfmt,...) const
Issue warning message.
Definition: TObject.cxx:879
virtual void Info(const char *method, const char *msgfmt,...) const
Issue info message.
Definition: TObject.cxx:867
const char * Data() const
Definition: TString.h:369
virtual Bool_t ExpandPathName(TString &path)
Expand a pathname getting rid of special shell characters like ~.
Definition: TSystem.cxx:1274
virtual int GetPid()
Get process id.
Definition: TSystem.cxx:710
virtual Bool_t AccessPathName(const char *path, EAccessMode mode=kFileExists)
Returns FALSE if one can access a file using the specified access mode.
Definition: TSystem.cxx:1296