diff options
Diffstat (limited to 'src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp')
| -rw-r--r-- | src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp b/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp new file mode 100644 index 00000000..ff7c312d --- /dev/null +++ b/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp @@ -0,0 +1,151 @@ +/** $Id: VBoxGuestR3LibPidFile.cpp $ */ +/** @file + * VBoxGuestR3Lib - Ring-3 Support Library for VirtualBox guest additions, + * Create a PID file. + */ + +/* + * Copyright (C) 2015-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include <iprt/file.h> +#include <iprt/string.h> +#include <iprt/process.h> +#include <iprt/thread.h> +#include <iprt/err.h> +#include "VBoxGuestR3LibInternal.h" + +/* A time to wait before starting the next attempt to check a pidfile. */ +#define VBGL_PIDFILE_WAIT_RELAX_TIME_MS (250) + +/** + * Creates a PID File and returns the open file descriptor. + * + * On DOS based system, file sharing (deny write) is used for locking the PID + * file. + * + * On Unix-y systems, an exclusive advisory lock is used for locking the PID + * file since the file sharing support is usually missing there. + * + * This API will overwrite any existing PID Files without a lock on them, on the + * assumption that they are stale files which an old process did not properly + * clean up. + * + * @returns IPRT status code. + * @param pszPath The path and filename to create the PID File under + * @param phFile Where to store the file descriptor of the open (and locked + * on Unix-y systems) PID File. On failure, or if another + * process owns the PID File, this will be set to NIL_RTFILE. + */ +VBGLR3DECL(int) VbglR3PidFile(const char *pszPath, PRTFILE phFile) +{ + AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER); + AssertPtrReturn(phFile, VERR_INVALID_PARAMETER); + *phFile = NIL_RTFILE; + + RTFILE hPidFile; + int rc = RTFileOpen(&hPidFile, pszPath, + RTFILE_O_READWRITE | RTFILE_O_OPEN_CREATE | RTFILE_O_DENY_WRITE + | (0644 << RTFILE_O_CREATE_MODE_SHIFT)); + if (RT_SUCCESS(rc)) + { +#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2) + /** @todo using size 0 for locking means lock all on Posix. + * We should adopt this as our convention too, or something + * similar. */ + rc = RTFileLock(hPidFile, RTFILE_LOCK_WRITE, 0, 0); + if (RT_FAILURE(rc)) + RTFileClose(hPidFile); + else +#endif + { + char szBuf[256]; + size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n", + RTProcSelf()); + RTFileWrite(hPidFile, szBuf, cbPid, NULL); + *phFile = hPidFile; + } + } + return rc; +} + + +/** + * Close and remove an open PID File. + * + * @param pszPath The path to the PID File, + * @param hFile The handle for the file. NIL_RTFILE is ignored as usual. + */ +VBGLR3DECL(void) VbglR3ClosePidFile(const char *pszPath, RTFILE hFile) +{ + AssertPtrReturnVoid(pszPath); + if (hFile != NIL_RTFILE) + { +#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2) + RTFileWriteAt(hFile, 0, "-1", 2, NULL); +#else + RTFileDelete(pszPath); +#endif + RTFileClose(hFile); + } +} + + +/** + * Wait for other process to release pidfile. + * + * This function is a wrapper to VbglR3PidFile(). + * + * @returns IPRT status code. + * @param szPidfile Path to pidfile. + * @param phPidfile Handle to pidfile. + * @param u64TimeoutMs A timeout value in milliseconds to wait for + * other process to release pidfile. + */ +VBGLR3DECL(int) VbglR3PidfileWait(const char *szPidfile, RTFILE *phPidfile, uint64_t u64TimeoutMs) +{ + int rc = VERR_FILE_LOCK_VIOLATION; + uint64_t u64Start = RTTimeSystemMilliTS(); + + AssertPtrReturn(szPidfile, VERR_INVALID_PARAMETER); + AssertPtrReturn(phPidfile, VERR_INVALID_PARAMETER); + + while ( !RT_SUCCESS((rc = VbglR3PidFile(szPidfile, phPidfile))) + && (RTTimeSystemMilliTS() - u64Start < u64TimeoutMs)) + { + RTThreadSleep(VBGL_PIDFILE_WAIT_RELAX_TIME_MS); + } + + return rc; +} |