1 | /** $Id: VBoxGuestR3LibPidFile.cpp 57730 2015-09-14 08:27:42Z vboxsync $ */
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2 | /** @file
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3 | * VBoxGuestR3Lib - Ring-3 Support Library for VirtualBox guest additions,
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4 | * Create a PID file.
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5 | */
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6 |
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7 | /*
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8 | * Copyright (C) 2015 Oracle Corporation
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9 | *
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10 | * This file is part of VirtualBox Open Source Edition (OSE), as
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11 | * available from http://www.virtualbox.org. This file is free software;
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12 | * you can redistribute it and/or modify it under the terms of the GNU
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13 | * General Public License (GPL) as published by the Free Software
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14 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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15 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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16 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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17 | *
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18 | * The contents of this file may alternatively be used under the terms
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19 | * of the Common Development and Distribution License Version 1.0
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20 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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21 | * VirtualBox OSE distribution, in which case the provisions of the
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22 | * CDDL are applicable instead of those of the GPL.
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23 | *
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24 | * You may elect to license modified versions of this file under the
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25 | * terms and conditions of either the GPL or the CDDL or both.
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26 | */
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27 |
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28 |
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29 | /*********************************************************************************************************************************
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30 | * Header Files *
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31 | *********************************************************************************************************************************/
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32 | #include <iprt/file.h>
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33 | #include <iprt/string.h>
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34 | #include <iprt/process.h>
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35 | #include "VBGLR3Internal.h"
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36 |
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37 | /**
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38 | * Creates a PID File and returns the open file descriptor.
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39 | *
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40 | * On DOS based system, file sharing (deny write) is used for locking the PID
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41 | * file.
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42 | *
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43 | * On Unix-y systems, an exclusive advisory lock is used for locking the PID
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44 | * file since the file sharing support is usually missing there.
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45 | *
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46 | * This API will overwrite any existing PID Files without a lock on them, on the
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47 | * assumption that they are stale files which an old process did not properly
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48 | * clean up.
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49 | *
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50 | * @returns IPRT status code.
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51 | * @param pszPath The path and filename to create the PID File under
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52 | * @param phFile Where to store the file descriptor of the open (and locked
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53 | * on Unix-y systems) PID File. On failure, or if another
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54 | * process owns the PID File, this will be set to NIL_RTFILE.
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55 | */
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56 | VBGLR3DECL(int) VbglR3PidFile(const char *pszPath, PRTFILE phFile)
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57 | {
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58 | AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
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59 | AssertPtrReturn(phFile, VERR_INVALID_PARAMETER);
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60 | *phFile = NIL_RTFILE;
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61 |
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62 | RTFILE hPidFile;
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63 | int rc = RTFileOpen(&hPidFile, pszPath,
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64 | RTFILE_O_READWRITE | RTFILE_O_OPEN_CREATE | RTFILE_O_DENY_WRITE
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65 | | (0644 << RTFILE_O_CREATE_MODE_SHIFT));
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66 | if (RT_SUCCESS(rc))
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67 | {
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68 | #if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
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69 | /** @todo using size 0 for locking means lock all on Posix.
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70 | * We should adopt this as our convention too, or something
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71 | * similar. */
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72 | rc = RTFileLock(hPidFile, RTFILE_LOCK_WRITE, 0, 0);
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73 | if (RT_FAILURE(rc))
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74 | RTFileClose(hPidFile);
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75 | else
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76 | #endif
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77 | {
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78 | char szBuf[256];
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79 | size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n",
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80 | RTProcSelf());
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81 | RTFileWrite(hPidFile, szBuf, cbPid, NULL);
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82 | *phFile = hPidFile;
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83 | }
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84 | }
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85 | return rc;
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86 | }
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87 |
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88 |
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89 | /**
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90 | * Close and remove an open PID File.
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91 | *
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92 | * @param pszPath The path to the PID File,
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93 | * @param hFile The handle for the file. NIL_RTFILE is ignored as usual.
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94 | */
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95 | VBGLR3DECL(void) VbglR3ClosePidFile(const char *pszPath, RTFILE hFile)
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96 | {
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97 | AssertPtrReturnVoid(pszPath);
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98 | if (hFile != NIL_RTFILE)
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99 | {
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100 | #if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
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101 | RTFileWriteAt(hFile, 0, "-1", 2, NULL);
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102 | #else
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103 | RTFileDelete(pszPath);
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104 | #endif
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105 | RTFileClose(hFile);
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106 | }
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107 | }
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108 |
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