| 1 | /** $Id: VBoxGuestR3LibDaemonize.cpp 11179 2008-08-06 14:45:17Z 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 Sun Microsystems, Inc.
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
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| 18 | * Clara, CA 95054 USA or visit http://www.sun.com if you need
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| 19 | * additional information or have any questions.
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| 20 | */
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| 21 |
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| 22 |
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| 23 | /*******************************************************************************
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| 24 | * Header Files *
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| 25 | *******************************************************************************/
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| 26 | #if defined(RT_OS_DARWIN)
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| 27 | # error "PORTME"
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| 28 |
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| 29 | #elif defined(RT_OS_OS2)
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| 30 | # define INCL_BASE
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| 31 | # define INCL_ERRORS
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| 32 | # include <os2.h>
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| 33 |
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| 34 | # include <iprt/alloca.h>
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| 35 | # include <iprt/string.h>
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| 36 |
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| 37 | #elif defined(RT_OS_WINDOWS)
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| 38 | # error "PORTME"
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| 39 |
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| 40 | #else /* the unices */
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| 41 | # include <sys/types.h>
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| 42 | # include <sys/stat.h>
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| 43 | # include <stdio.h>
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| 44 | # include <fcntl.h>
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| 45 | # include <stdlib.h>
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| 46 | # include <unistd.h>
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| 47 | # include <signal.h>
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| 48 | # include <errno.h>
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| 49 | #endif
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| 50 |
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| 51 | #include <iprt/string.h>
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| 52 | #include <iprt/file.h>
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| 53 | #include <VBox/VBoxGuest.h>
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| 54 |
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| 55 |
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| 56 | /**
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| 57 | * Daemonize the process for running in the background.
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| 58 | *
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| 59 | * This is supposed to do the same job as the BSD daemon() call.
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| 60 | *
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| 61 | * @returns 0 on success
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| 62 | *
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| 63 | * @param fNoChDir Pass false to change working directory to root.
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| 64 | * @param fNoClose Pass false to redirect standard file streams to /dev/null.
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| 65 | * @param pszPidfile Path to a file to write the pid of the daemon process
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| 66 | * to. Daemonising will fail if this file already exists
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| 67 | * or cannot be written. Optional.
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| 68 | */
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| 69 | VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose,
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| 70 | char const *pszPidfile)
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| 71 | {
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| 72 | #if defined(RT_OS_DARWIN)
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| 73 | # error "PORTME"
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| 74 |
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| 75 | #elif defined(RT_OS_OS2)
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| 76 | /** @todo create a pidfile if this is (/was :) ) usual on OS/2 */
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| 77 | NOREF(pszPidfile);
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| 78 | PPIB pPib;
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| 79 | PTIB pTib;
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| 80 | DosGetInfoBlocks(&pTib, &pPib);
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| 81 |
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| 82 | /* Get the full path to the executable. */
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| 83 | char szExe[CCHMAXPATH];
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| 84 | APIRET rc = DosQueryModuleName(pPib->pib_hmte, sizeof(szExe), szExe);
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| 85 | if (rc)
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| 86 | return RTErrConvertFromOS2(rc);
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| 87 |
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| 88 | /* calc the length of the command line. */
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| 89 | char *pch = pPib->pib_pchcmd;
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| 90 | size_t cch0 = strlen(pch);
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| 91 | pch += cch0 + 1;
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| 92 | size_t cch1 = strlen(pch);
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| 93 | pch += cch1 + 1;
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| 94 | char *pchArgs;
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| 95 | if (cch1 && *pch)
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| 96 | {
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| 97 | do pch = strchr(pch, '\0') + 1;
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| 98 | while (*pch);
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| 99 |
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| 100 | size_t cchTotal = pch - pPib->pib_pchcmd;
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| 101 | pchArgs = (char *)alloca(cchTotal + sizeof("--daemonized\0\0"));
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| 102 | memcpy(pchArgs, pPib->pib_pchcmd, cchTotal - 1);
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| 103 | memcpy(pchArgs + cchTotal - 1, "--daemonized\0\0", sizeof("--daemonized\0\0"));
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| 104 | }
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| 105 | else
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| 106 | {
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| 107 | size_t cchTotal = pch - pPib->pib_pchcmd + 1;
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| 108 | pchArgs = (char *)alloca(cchTotal + sizeof(" --daemonized "));
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| 109 | memcpy(pchArgs, pPib->pib_pchcmd, cch0 + 1);
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| 110 | pch = pchArgs + cch0 + 1;
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| 111 | memcpy(pch, " --daemonized ", sizeof(" --daemonized ") - 1);
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| 112 | pch += sizeof(" --daemonized ") - 1;
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| 113 | if (cch1)
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| 114 | memcpy(pch, pPib->pib_pchcmd + cch0 + 1, cch1 + 2);
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| 115 | else
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| 116 | pch[0] = pch[1] = '\0';
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| 117 | }
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| 118 |
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| 119 | /* spawn a detach process */
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| 120 | char szObj[128];
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| 121 | RESULTCODES ResCodes = { 0, 0 };
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| 122 | szObj[0] = '\0';
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| 123 | rc = DosExecPgm(szObj, sizeof(szObj), EXEC_BACKGROUND, (PCSZ)pchArgs, NULL, &ResCodes, (PCSZ)szExe);
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| 124 | if (rc)
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| 125 | {
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| 126 | /** @todo Change this to some standard log/print error?? */
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| 127 | /* VBoxServiceError("DosExecPgm failed with rc=%d and szObj='%s'\n", rc, szObj); */
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| 128 | return RTErrConvertFromOS2(rc);
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| 129 | }
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| 130 | DosExit(EXIT_PROCESS, 0);
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| 131 | return VERR_GENERAL_FAILURE;
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| 132 |
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| 133 | #elif defined(RT_OS_WINDOWS)
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| 134 | # error "PORTME"
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| 135 |
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| 136 | #else /* the unices */
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| 137 | /*
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| 138 | * Fork the child process in a new session and quit the parent.
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| 139 | *
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| 140 | * - fork once and create a new session (setsid). This will detach us
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| 141 | * from the controlling tty meaning that we won't receive the SIGHUP
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| 142 | * (or any other signal) sent to that session.
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| 143 | * - The SIGHUP signal is ignored because the session/parent may throw
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| 144 | * us one before we get to the setsid.
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| 145 | * - When the parent exit(0) we will become an orphan and re-parented to
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| 146 | * the init process.
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| 147 | * - Because of the Linux / System V sematics of assigning the controlling
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| 148 | * tty automagically when a session leader first opens a tty, we will
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| 149 | * fork() once more on Linux to get rid of the session leadership role.
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| 150 | */
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| 151 |
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| 152 | /* We start off by opening the pidfile, so that we can fail straight away
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| 153 | * if it already exists. */
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| 154 | RTFILE hPidfile = NIL_RTFILE;
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| 155 | if (pszPidfile != NULL)
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| 156 | {
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| 157 | /* @note the exclusive create is not guaranteed on all file
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| 158 | * systems (e.g. NFSv2) */
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| 159 | int rc = RTFileOpen(&hPidfile, pszPidfile,
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| 160 | RTFILE_O_READWRITE | RTFILE_O_CREATE
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| 161 | | (0644 << RTFILE_O_CREATE_MODE_SHIFT));
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| 162 | if (!RT_SUCCESS(rc))
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| 163 | return rc;
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| 164 | }
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| 165 |
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| 166 | struct sigaction OldSigAct;
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| 167 | struct sigaction SigAct;
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| 168 | memset(&SigAct, 0, sizeof(SigAct));
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| 169 | SigAct.sa_handler = SIG_IGN;
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| 170 | int rcSigAct = sigaction(SIGHUP, &SigAct, &OldSigAct);
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| 171 |
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| 172 | pid_t pid = fork();
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| 173 | if (pid == -1)
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| 174 | return RTErrConvertFromErrno(errno);
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| 175 | if (pid != 0)
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| 176 | {
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| 177 | # ifndef RT_OS_LINUX /* On Linux we do another fork later */
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| 178 | if (hPidfile != NIL_RTFILE)
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| 179 | {
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| 180 | char szBuf[256];
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| 181 | size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n", pid);
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| 182 | RTFileWrite(hPidfile, szBuf, cbPid, NULL);
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| 183 | RTFileClose(hPidfile);
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| 184 | }
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| 185 | # endif
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| 186 | exit(0);
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| 187 | }
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| 188 |
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| 189 | /*
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| 190 | * The orphaned child becomes is reparented to the init process.
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| 191 | * We create a new session for it (setsid), point the standard
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| 192 | * file descriptors to /dev/null, and change to the root directory.
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| 193 | */
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| 194 | pid_t newpgid = setsid();
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| 195 | int SavedErrno = errno;
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| 196 | if (rcSigAct != -1)
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| 197 | sigaction(SIGHUP, &OldSigAct, NULL);
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| 198 | if (newpgid == -1)
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| 199 | return RTErrConvertFromErrno(SavedErrno);
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| 200 |
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| 201 | if (!fNoClose)
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| 202 | {
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| 203 | /* Open stdin(0), stdout(1) and stderr(2) as /dev/null. */
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| 204 | int fd = open("/dev/null", O_RDWR);
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| 205 | if (fd == -1) /* paranoia */
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| 206 | {
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| 207 | close(STDIN_FILENO);
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| 208 | close(STDOUT_FILENO);
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| 209 | close(STDERR_FILENO);
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| 210 | fd = open("/dev/null", O_RDWR);
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| 211 | }
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| 212 | if (fd != -1)
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| 213 | {
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| 214 | dup2(fd, STDIN_FILENO);
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| 215 | dup2(fd, STDOUT_FILENO);
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| 216 | dup2(fd, STDERR_FILENO);
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| 217 | if (fd > 2)
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| 218 | close(fd);
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| 219 | }
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| 220 | }
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| 221 |
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| 222 | if (!fNoChDir)
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| 223 | chdir("/");
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| 224 |
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| 225 | /*
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| 226 | * Change the umask - this is non-standard daemon() behavior.
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| 227 | */
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| 228 | umask(027);
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| 229 |
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| 230 | # ifdef RT_OS_LINUX
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| 231 | /*
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| 232 | * And fork again to lose session leader status (non-standard daemon()
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| 233 | * behaviour).
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| 234 | */
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| 235 | pid = fork();
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| 236 | if (pid == -1)
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| 237 | return RTErrConvertFromErrno(errno);
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| 238 | if (pid != 0)
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| 239 | {
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| 240 | if (hPidfile != NIL_RTFILE)
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| 241 | {
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| 242 | char szBuf[256];
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| 243 | size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n", pid);
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| 244 | RTFileWrite(hPidfile, szBuf, cbPid, NULL);
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| 245 | RTFileClose(hPidfile);
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| 246 | }
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| 247 | exit(0);
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| 248 | }
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| 249 | # endif /* RT_OS_LINUX */
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| 250 |
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| 251 | return VINF_SUCCESS;
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| 252 | #endif
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| 253 | }
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| 254 |
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