| 1 | /** $Id: VBoxGuestR3LibDaemonize.cpp 98475 2023-02-03 19:27:47Z vboxsync $ */
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| 2 | /** @file
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| 3 | * VBoxGuestR3Lib - Ring-3 Support Library for VirtualBox guest additions, daemonize a process.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2007-2023 Oracle and/or its affiliates.
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| 8 | *
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| 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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| 11 | *
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| 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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| 25 | * The contents of this file may alternatively be used under the terms
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| 26 | * of the Common Development and Distribution License Version 1.0
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| 27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | * in the VirtualBox distribution, in which case the provisions of the
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| 29 | * CDDL are applicable instead of those of the GPL.
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| 30 | *
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| 31 | * You may elect to license modified versions of this file under the
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| 32 | * terms and conditions of either the GPL or the CDDL or both.
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| 33 | *
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| 34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | */
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| 36 |
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| 37 |
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| 38 | /*********************************************************************************************************************************
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| 39 | * Header Files *
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| 40 | *********************************************************************************************************************************/
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| 41 | #if defined(RT_OS_OS2)
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| 42 | # define INCL_BASE
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| 43 | # define INCL_ERRORS
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| 44 | # include <os2.h>
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| 45 |
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| 46 | # include <iprt/alloca.h>
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| 47 | # include <iprt/string.h>
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| 48 |
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| 49 | #elif defined(RT_OS_WINDOWS)
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| 50 | # error "PORTME"
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| 51 |
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| 52 | #else /* the unices */
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| 53 | # include <sys/types.h>
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| 54 | # include <sys/stat.h>
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| 55 | # include <sys/wait.h>
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| 56 | # include <stdio.h>
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| 57 | # include <fcntl.h>
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| 58 | # include <stdlib.h>
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| 59 | # include <unistd.h>
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| 60 | # include <signal.h>
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| 61 | # include <errno.h>
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| 62 | #endif
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| 63 |
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| 64 | #include <iprt/process.h>
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| 65 | #include <iprt/string.h>
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| 66 | #include <VBox/err.h>
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| 67 | #include <VBox/log.h>
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| 68 |
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| 69 | #include "VBoxGuestR3LibInternal.h"
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| 70 |
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| 71 |
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| 72 | /**
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| 73 | * Daemonize the process for running in the background.
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| 74 | *
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| 75 | * This is supposed to do the same job as the BSD daemon() call.
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| 76 | *
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| 77 | * @returns 0 on success
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| 78 | *
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| 79 | * @param fNoChDir Pass false to change working directory to root.
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| 80 | * @param fNoClose Pass false to redirect standard file streams to /dev/null.
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| 81 | * @param fRespawn Restart the daemonised process after five seconds if it
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| 82 | * terminates abnormally.
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| 83 | * @param pcRespawn Where to store a count of how often we have respawned,
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| 84 | * intended for avoiding error spamming. Optional.
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| 85 | * @param fReturnOnUpdate If True, this function will return control to caller when
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| 86 | * child process will terminate with exit code of VBGLR3EXITCODERELOAD,
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| 87 | * indicating that Guest Additions update has been started and this running
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| 88 | * process will be asked to be restarted by arrival of the next SIGUSR1
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| 89 | * signal (caller should wait for SIGUSR1). If False, this functions will
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| 90 | * never return, but rather exit() when child process terminates with
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| 91 | * exit code 0.
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| 92 | * @param pfUpdateStarted A flag which passed to caller if fReturnOnUpdate is True (can be NULL).
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| 93 | * @param szPidfile Optional path to parent process' pidfile (can be NULL).
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| 94 | * @param phPidfile Optional path to parent process' pidfile handle (can not be NULL if
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| 95 | * szPidfile was specified).
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| 96 | *
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| 97 | * @todo Use RTProcDaemonize instead of this.
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| 98 | * @todo Implement fRespawn on OS/2.
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| 99 | * @todo Make the respawn interval configurable. But not until someone
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| 100 | * actually needs that.
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| 101 | */
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| 102 | VBGLR3DECL(int) VbglR3DaemonizeEx(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn,
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| 103 | bool fReturnOnUpdate, bool *pfUpdateStarted, const char *szPidfile,
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| 104 | RTFILE *phPidfile)
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| 105 | {
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| 106 | #if defined(RT_OS_OS2)
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| 107 | PPIB pPib;
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| 108 | PTIB pTib;
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| 109 | DosGetInfoBlocks(&pTib, &pPib);
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| 110 |
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| 111 | RT_NOREF(fReturnOnUpdate);
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| 112 | RT_NOREF(pfUpdateStarted);
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| 113 | RT_NOREF(szPidfile);
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| 114 | RT_NOREF(phPidfile);
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| 115 |
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| 116 | AssertRelease(!fRespawn);
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| 117 | /* Get the full path to the executable. */
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| 118 | char szExe[CCHMAXPATH];
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| 119 | APIRET rc = DosQueryModuleName(pPib->pib_hmte, sizeof(szExe), szExe);
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| 120 | if (rc)
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| 121 | return RTErrConvertFromOS2(rc);
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| 122 |
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| 123 | /* calc the length of the command line. */
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| 124 | char *pch = pPib->pib_pchcmd;
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| 125 | size_t cch0 = strlen(pch);
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| 126 | pch += cch0 + 1;
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| 127 | size_t cch1 = strlen(pch);
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| 128 | pch += cch1 + 1;
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| 129 | char *pchArgs;
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| 130 | if (cch1 && *pch)
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| 131 | {
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| 132 | do pch = strchr(pch, '\0') + 1;
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| 133 | while (*pch);
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| 134 |
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| 135 | size_t cchTotal = pch - pPib->pib_pchcmd;
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| 136 | pchArgs = (char *)alloca(cchTotal + sizeof("--daemonized\0\0"));
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| 137 | memcpy(pchArgs, pPib->pib_pchcmd, cchTotal - 1);
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| 138 | memcpy(pchArgs + cchTotal - 1, "--daemonized\0\0", sizeof("--daemonized\0\0"));
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| 139 | }
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| 140 | else
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| 141 | {
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| 142 | size_t cchTotal = pch - pPib->pib_pchcmd + 1;
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| 143 | pchArgs = (char *)alloca(cchTotal + sizeof(" --daemonized "));
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| 144 | memcpy(pchArgs, pPib->pib_pchcmd, cch0 + 1);
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| 145 | pch = pchArgs + cch0 + 1;
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| 146 | memcpy(pch, " --daemonized ", sizeof(" --daemonized ") - 1);
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| 147 | pch += sizeof(" --daemonized ") - 1;
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| 148 | if (cch1)
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| 149 | memcpy(pch, pPib->pib_pchcmd + cch0 + 1, cch1 + 2);
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| 150 | else
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| 151 | pch[0] = pch[1] = '\0';
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| 152 | }
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| 153 |
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| 154 | /* spawn a detach process */
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| 155 | char szObj[128];
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| 156 | RESULTCODES ResCodes = { 0, 0 };
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| 157 | szObj[0] = '\0';
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| 158 | rc = DosExecPgm(szObj, sizeof(szObj), EXEC_BACKGROUND, (PCSZ)pchArgs, NULL, &ResCodes, (PCSZ)szExe);
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| 159 | if (rc)
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| 160 | {
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| 161 | /** @todo Change this to some standard log/print error?? */
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| 162 | /* VBoxServiceError("DosExecPgm failed with rc=%d and szObj='%s'\n", rc, szObj); */
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| 163 | return RTErrConvertFromOS2(rc);
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| 164 | }
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| 165 | DosExit(EXIT_PROCESS, 0);
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| 166 | return VERR_GENERAL_FAILURE;
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| 167 |
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| 168 | #elif defined(RT_OS_WINDOWS)
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| 169 | # error "PORTME"
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| 170 |
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| 171 | #else /* the unices */
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| 172 | /*
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| 173 | * Fork the child process in a new session and quit the parent.
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| 174 | *
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| 175 | * - fork once and create a new session (setsid). This will detach us
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| 176 | * from the controlling tty meaning that we won't receive the SIGHUP
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| 177 | * (or any other signal) sent to that session.
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| 178 | * - The SIGHUP signal is ignored because the session/parent may throw
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| 179 | * us one before we get to the setsid.
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| 180 | * - When the parent exit(0) we will become an orphan and re-parented to
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| 181 | * the init process.
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| 182 | * - Because of the Linux / System V semantics of assigning the controlling
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| 183 | * tty automagically when a session leader first opens a tty, we will
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| 184 | * fork() once more on Linux to get rid of the session leadership role.
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| 185 | */
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| 186 |
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| 187 | struct sigaction OldSigAct;
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| 188 | struct sigaction SigAct;
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| 189 | RT_ZERO(SigAct);
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| 190 | SigAct.sa_handler = SIG_IGN;
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| 191 | int rcSigAct = sigaction(SIGHUP, &SigAct, &OldSigAct);
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| 192 |
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| 193 | pid_t pid = fork();
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| 194 | if (pid == -1)
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| 195 | return RTErrConvertFromErrno(errno);
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| 196 | if (pid != 0)
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| 197 | exit(0);
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| 198 |
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| 199 | /*
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| 200 | * The orphaned child becomes is reparented to the init process.
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| 201 | * We create a new session for it (setsid), point the standard
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| 202 | * file descriptors to /dev/null, and change to the root directory.
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| 203 | */
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| 204 | pid_t newpgid = setsid();
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| 205 | int SavedErrno = errno;
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| 206 | if (rcSigAct != -1)
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| 207 | sigaction(SIGHUP, &OldSigAct, NULL);
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| 208 | if (newpgid == -1)
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| 209 | return RTErrConvertFromErrno(SavedErrno);
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| 210 |
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| 211 | if (!fNoClose)
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| 212 | {
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| 213 | /* Open stdin(0), stdout(1) and stderr(2) as /dev/null. */
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| 214 | int fd = open("/dev/null", O_RDWR);
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| 215 | if (fd == -1) /* paranoia */
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| 216 | {
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| 217 | close(STDIN_FILENO);
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| 218 | close(STDOUT_FILENO);
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| 219 | close(STDERR_FILENO);
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| 220 | fd = open("/dev/null", O_RDWR);
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| 221 | }
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| 222 | if (fd != -1)
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| 223 | {
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| 224 | dup2(fd, STDIN_FILENO);
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| 225 | dup2(fd, STDOUT_FILENO);
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| 226 | dup2(fd, STDERR_FILENO);
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| 227 | if (fd > 2)
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| 228 | close(fd);
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| 229 | }
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| 230 | }
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| 231 |
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| 232 | if (!fNoChDir)
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| 233 | {
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| 234 | int rcShutUpGcc = chdir("/");
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| 235 | RT_NOREF_PV(rcShutUpGcc);
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| 236 | }
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| 237 |
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| 238 | /*
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| 239 | * Change the umask - this is non-standard daemon() behavior.
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| 240 | */
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| 241 | umask(027);
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| 242 |
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| 243 | # ifdef RT_OS_LINUX
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| 244 | /*
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| 245 | * And fork again to lose session leader status (non-standard daemon()
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| 246 | * behaviour).
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| 247 | */
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| 248 | pid = fork();
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| 249 | if (pid == -1)
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| 250 | return RTErrConvertFromErrno(errno);
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| 251 | if (pid != 0)
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| 252 | exit(0);
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| 253 | # endif /* RT_OS_LINUX */
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| 254 |
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| 255 | /* Check if another instance is already running. */
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| 256 | if (szPidfile != NULL)
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| 257 | {
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| 258 | if (phPidfile != NULL)
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| 259 | {
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| 260 | int rc = VbglR3PidfileWait(szPidfile, phPidfile, 5000);
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| 261 |
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| 262 | /* Another instance of process is already running. */
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| 263 | if (rc == VERR_FILE_LOCK_VIOLATION)
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| 264 | {
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| 265 | LogRel(("cannot aquire pidfile %s, exitting\n", szPidfile));
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| 266 | exit(1);
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| 267 | }
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| 268 |
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| 269 | /* Unable to lock on pidfile. */
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| 270 | if (RT_FAILURE(rc))
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| 271 | exit(1);
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| 272 | }
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| 273 | else
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| 274 | return VERR_INVALID_PARAMETER;
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| 275 | }
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| 276 |
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| 277 | if (fRespawn)
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| 278 | {
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| 279 | /* We implement re-spawning as a third fork(), with the parent process
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| 280 | * monitoring the child and re-starting it after a delay if it exits
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| 281 | * abnormally. */
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| 282 | unsigned cRespawn = 0;
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| 283 | for (;;)
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| 284 | {
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| 285 | int iStatus, rcWait;
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| 286 |
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| 287 | if (pcRespawn != NULL)
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| 288 | *pcRespawn = cRespawn;
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| 289 | pid = fork();
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| 290 | if (pid == -1)
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| 291 | return RTErrConvertFromErrno(errno);
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| 292 | if (pid == 0)
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| 293 | return VINF_SUCCESS;
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| 294 | do
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| 295 | rcWait = waitpid(pid, &iStatus, 0);
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| 296 | while (rcWait == -1 && errno == EINTR);
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| 297 | if (rcWait == -1)
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| 298 | exit(1);
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| 299 | if (WIFEXITED(iStatus))
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| 300 | {
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| 301 | if (WEXITSTATUS(iStatus) == 0)
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| 302 | exit(0);
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| 303 | else if (fReturnOnUpdate && WEXITSTATUS(iStatus) == VBGLR3EXITCODERELOAD)
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| 304 | {
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| 305 | /* Tell caller that update has been started. */
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| 306 | if (pfUpdateStarted != NULL)
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| 307 | *pfUpdateStarted = true;
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| 308 |
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| 309 | return VINF_SUCCESS;
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| 310 | }
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| 311 | }
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| 312 | sleep(5);
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| 313 | ++cRespawn;
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| 314 | }
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| 315 | }
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| 316 | return VINF_SUCCESS;
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| 317 | #endif
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| 318 | }
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| 319 |
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| 320 | /**
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| 321 | * A wrapper function for VbglR3DaemonizeEx.
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| 322 | */
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| 323 | VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn)
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| 324 | {
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| 325 | return VbglR3DaemonizeEx(fNoChDir, fNoClose, fRespawn, pcRespawn, false, NULL, NULL, NULL);
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| 326 | }
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