| 1 | /** $Id: VBoxGuestR3LibPidFile.cpp 96407 2022-08-22 17:43:14Z 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) 2015-2022 Oracle and/or its affiliates.
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| 9 | *
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| 10 | * This file is part of VirtualBox base platform packages, as
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| 11 | * available from https://www.virtualbox.org.
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| 12 | *
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| 13 | * This program is free software; you can redistribute it and/or
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| 14 | * modify it under the terms of the GNU General Public License
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| 15 | * as published by the Free Software Foundation, in version 3 of the
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| 16 | * License.
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| 17 | *
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| 18 | * This program is distributed in the hope that it will be useful, but
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| 19 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 21 | * General Public License for more details.
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| 22 | *
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| 23 | * You should have received a copy of the GNU General Public License
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| 24 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 25 | *
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| 26 | * The contents of this file may alternatively be used under the terms
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| 27 | * of the Common Development and Distribution License Version 1.0
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| 28 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 29 | * in the VirtualBox distribution, in which case the provisions of the
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| 30 | * CDDL are applicable instead of those of the GPL.
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| 31 | *
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| 32 | * You may elect to license modified versions of this file under the
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| 33 | * terms and conditions of either the GPL or the CDDL or both.
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| 34 | *
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| 35 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 36 | */
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| 37 |
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| 38 |
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| 39 | /*********************************************************************************************************************************
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| 40 | * Header Files *
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| 41 | *********************************************************************************************************************************/
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| 42 | #include <iprt/file.h>
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| 43 | #include <iprt/string.h>
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| 44 | #include <iprt/process.h>
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| 45 | #include "VBoxGuestR3LibInternal.h"
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| 46 |
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| 47 | /**
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| 48 | * Creates a PID File and returns the open file descriptor.
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| 49 | *
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| 50 | * On DOS based system, file sharing (deny write) is used for locking the PID
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| 51 | * file.
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| 52 | *
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| 53 | * On Unix-y systems, an exclusive advisory lock is used for locking the PID
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| 54 | * file since the file sharing support is usually missing there.
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| 55 | *
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| 56 | * This API will overwrite any existing PID Files without a lock on them, on the
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| 57 | * assumption that they are stale files which an old process did not properly
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| 58 | * clean up.
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| 59 | *
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| 60 | * @returns IPRT status code.
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| 61 | * @param pszPath The path and filename to create the PID File under
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| 62 | * @param phFile Where to store the file descriptor of the open (and locked
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| 63 | * on Unix-y systems) PID File. On failure, or if another
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| 64 | * process owns the PID File, this will be set to NIL_RTFILE.
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| 65 | */
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| 66 | VBGLR3DECL(int) VbglR3PidFile(const char *pszPath, PRTFILE phFile)
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| 67 | {
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| 68 | AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
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| 69 | AssertPtrReturn(phFile, VERR_INVALID_PARAMETER);
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| 70 | *phFile = NIL_RTFILE;
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| 71 |
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| 72 | RTFILE hPidFile;
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| 73 | int rc = RTFileOpen(&hPidFile, pszPath,
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| 74 | RTFILE_O_READWRITE | RTFILE_O_OPEN_CREATE | RTFILE_O_DENY_WRITE
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| 75 | | (0644 << RTFILE_O_CREATE_MODE_SHIFT));
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| 76 | if (RT_SUCCESS(rc))
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| 77 | {
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| 78 | #if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
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| 79 | /** @todo using size 0 for locking means lock all on Posix.
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| 80 | * We should adopt this as our convention too, or something
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| 81 | * similar. */
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| 82 | rc = RTFileLock(hPidFile, RTFILE_LOCK_WRITE, 0, 0);
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| 83 | if (RT_FAILURE(rc))
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| 84 | RTFileClose(hPidFile);
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| 85 | else
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| 86 | #endif
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| 87 | {
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| 88 | char szBuf[256];
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| 89 | size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n",
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| 90 | RTProcSelf());
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| 91 | RTFileWrite(hPidFile, szBuf, cbPid, NULL);
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| 92 | *phFile = hPidFile;
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| 93 | }
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| 94 | }
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| 95 | return rc;
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| 96 | }
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| 97 |
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| 98 |
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| 99 | /**
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| 100 | * Close and remove an open PID File.
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| 101 | *
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| 102 | * @param pszPath The path to the PID File,
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| 103 | * @param hFile The handle for the file. NIL_RTFILE is ignored as usual.
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| 104 | */
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| 105 | VBGLR3DECL(void) VbglR3ClosePidFile(const char *pszPath, RTFILE hFile)
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| 106 | {
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| 107 | AssertPtrReturnVoid(pszPath);
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| 108 | if (hFile != NIL_RTFILE)
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| 109 | {
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| 110 | #if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
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| 111 | RTFileWriteAt(hFile, 0, "-1", 2, NULL);
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| 112 | #else
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| 113 | RTFileDelete(pszPath);
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| 114 | #endif
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| 115 | RTFileClose(hFile);
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| 116 | }
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| 117 | }
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| 118 |
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