1 | /** $Id: VBoxGuestR3LibDaemonize.cpp 53421 2014-12-01 16:00:30Z 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) 2007-2010 Oracle Corporation
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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 | * The contents of this file may alternatively be used under the terms
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18 | * of the Common Development and Distribution License Version 1.0
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19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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20 | * VirtualBox OSE distribution, in which case the provisions of the
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21 | * CDDL are applicable instead of those of the GPL.
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22 | *
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23 | * You may elect to license modified versions of this file under the
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24 | * terms and conditions of either the GPL or the CDDL or both.
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25 | */
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26 |
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27 |
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28 | /*******************************************************************************
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29 | * Header Files *
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30 | *******************************************************************************/
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31 | #if defined(RT_OS_OS2)
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32 | # define INCL_BASE
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33 | # define INCL_ERRORS
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34 | # include <os2.h>
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35 |
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36 | # include <iprt/alloca.h>
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37 | # include <iprt/string.h>
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38 |
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39 | #elif defined(RT_OS_WINDOWS)
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40 | # error "PORTME"
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41 |
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42 | #else /* the unices */
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43 | # include <sys/types.h>
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44 | # include <sys/stat.h>
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45 | # include <sys/wait.h>
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46 | # include <stdio.h>
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47 | # include <fcntl.h>
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48 | # include <stdlib.h>
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49 | # include <unistd.h>
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50 | # include <signal.h>
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51 | # include <errno.h>
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52 | #endif
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53 |
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54 | #include <iprt/file.h>
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55 | #include <iprt/process.h>
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56 | #include <iprt/string.h>
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57 | #include "VBGLR3Internal.h"
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58 |
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59 |
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60 | /**
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61 | * Daemonize the process for running in the background.
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62 | *
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63 | * This is supposed to do the same job as the BSD daemon() call.
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64 | *
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65 | * @returns 0 on success
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66 | *
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67 | * @param fNoChDir Pass false to change working directory to root.
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68 | * @param fNoClose Pass false to redirect standard file streams to /dev/null.
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69 | * @param fRespawn Restart the daemonised process after five seconds if it
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70 | * terminates abnormally.
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71 | *
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72 | * @todo Use RTProcDaemonize instead of this.
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73 | * @todo Implement fRespawn on OS/2.
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74 | * @todo Make the respawn interval configurable. But not until someone
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75 | * actually needs that.
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76 | */
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77 | VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn)
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78 | {
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79 | #if defined(RT_OS_OS2)
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80 | PPIB pPib;
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81 | PTIB pTib;
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82 | DosGetInfoBlocks(&pTib, &pPib);
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83 |
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84 | AssertRelease(!fRespawn);
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85 | /* Get the full path to the executable. */
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86 | char szExe[CCHMAXPATH];
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87 | APIRET rc = DosQueryModuleName(pPib->pib_hmte, sizeof(szExe), szExe);
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88 | if (rc)
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89 | return RTErrConvertFromOS2(rc);
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90 |
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91 | /* calc the length of the command line. */
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92 | char *pch = pPib->pib_pchcmd;
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93 | size_t cch0 = strlen(pch);
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94 | pch += cch0 + 1;
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95 | size_t cch1 = strlen(pch);
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96 | pch += cch1 + 1;
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97 | char *pchArgs;
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98 | if (cch1 && *pch)
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99 | {
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100 | do pch = strchr(pch, '\0') + 1;
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101 | while (*pch);
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102 |
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103 | size_t cchTotal = pch - pPib->pib_pchcmd;
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104 | pchArgs = (char *)alloca(cchTotal + sizeof("--daemonized\0\0"));
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105 | memcpy(pchArgs, pPib->pib_pchcmd, cchTotal - 1);
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106 | memcpy(pchArgs + cchTotal - 1, "--daemonized\0\0", sizeof("--daemonized\0\0"));
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107 | }
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108 | else
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109 | {
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110 | size_t cchTotal = pch - pPib->pib_pchcmd + 1;
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111 | pchArgs = (char *)alloca(cchTotal + sizeof(" --daemonized "));
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112 | memcpy(pchArgs, pPib->pib_pchcmd, cch0 + 1);
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113 | pch = pchArgs + cch0 + 1;
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114 | memcpy(pch, " --daemonized ", sizeof(" --daemonized ") - 1);
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115 | pch += sizeof(" --daemonized ") - 1;
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116 | if (cch1)
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117 | memcpy(pch, pPib->pib_pchcmd + cch0 + 1, cch1 + 2);
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118 | else
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119 | pch[0] = pch[1] = '\0';
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120 | }
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121 |
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122 | /* spawn a detach process */
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123 | char szObj[128];
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124 | RESULTCODES ResCodes = { 0, 0 };
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125 | szObj[0] = '\0';
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126 | rc = DosExecPgm(szObj, sizeof(szObj), EXEC_BACKGROUND, (PCSZ)pchArgs, NULL, &ResCodes, (PCSZ)szExe);
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127 | if (rc)
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128 | {
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129 | /** @todo Change this to some standard log/print error?? */
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130 | /* VBoxServiceError("DosExecPgm failed with rc=%d and szObj='%s'\n", rc, szObj); */
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131 | return RTErrConvertFromOS2(rc);
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132 | }
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133 | DosExit(EXIT_PROCESS, 0);
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134 | return VERR_GENERAL_FAILURE;
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135 |
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136 | #elif defined(RT_OS_WINDOWS)
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137 | # error "PORTME"
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138 |
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139 | #else /* the unices */
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140 | /*
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141 | * Fork the child process in a new session and quit the parent.
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142 | *
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143 | * - fork once and create a new session (setsid). This will detach us
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144 | * from the controlling tty meaning that we won't receive the SIGHUP
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145 | * (or any other signal) sent to that session.
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146 | * - The SIGHUP signal is ignored because the session/parent may throw
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147 | * us one before we get to the setsid.
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148 | * - When the parent exit(0) we will become an orphan and re-parented to
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149 | * the init process.
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150 | * - Because of the Linux / System V semantics of assigning the controlling
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151 | * tty automagically when a session leader first opens a tty, we will
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152 | * fork() once more on Linux to get rid of the session leadership role.
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153 | */
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154 |
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155 | struct sigaction OldSigAct;
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156 | struct sigaction SigAct;
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157 | RT_ZERO(SigAct);
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158 | SigAct.sa_handler = SIG_IGN;
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159 | int rcSigAct = sigaction(SIGHUP, &SigAct, &OldSigAct);
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160 |
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161 | pid_t pid = fork();
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162 | if (pid == -1)
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163 | return RTErrConvertFromErrno(errno);
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164 | if (pid != 0)
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165 | exit(0);
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166 |
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167 | /*
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168 | * The orphaned child becomes is reparented to the init process.
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169 | * We create a new session for it (setsid), point the standard
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170 | * file descriptors to /dev/null, and change to the root directory.
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171 | */
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172 | pid_t newpgid = setsid();
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173 | int SavedErrno = errno;
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174 | if (rcSigAct != -1)
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175 | sigaction(SIGHUP, &OldSigAct, NULL);
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176 | if (newpgid == -1)
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177 | return RTErrConvertFromErrno(SavedErrno);
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178 |
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179 | if (!fNoClose)
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180 | {
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181 | /* Open stdin(0), stdout(1) and stderr(2) as /dev/null. */
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182 | int fd = open("/dev/null", O_RDWR);
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183 | if (fd == -1) /* paranoia */
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184 | {
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185 | close(STDIN_FILENO);
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186 | close(STDOUT_FILENO);
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187 | close(STDERR_FILENO);
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188 | fd = open("/dev/null", O_RDWR);
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189 | }
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190 | if (fd != -1)
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191 | {
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192 | dup2(fd, STDIN_FILENO);
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193 | dup2(fd, STDOUT_FILENO);
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194 | dup2(fd, STDERR_FILENO);
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195 | if (fd > 2)
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196 | close(fd);
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197 | }
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198 | }
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199 |
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200 | if (!fNoChDir)
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201 | chdir("/");
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202 |
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203 | /*
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204 | * Change the umask - this is non-standard daemon() behavior.
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205 | */
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206 | umask(027);
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207 |
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208 | # ifdef RT_OS_LINUX
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209 | /*
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210 | * And fork again to lose session leader status (non-standard daemon()
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211 | * behaviour).
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212 | */
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213 | pid = fork();
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214 | if (pid == -1)
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215 | return RTErrConvertFromErrno(errno);
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216 | if (pid != 0)
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217 | exit(0);
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218 | # endif /* RT_OS_LINUX */
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219 |
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220 | if (fRespawn)
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221 | /* We implement re-spawning as a third fork(), with the parent process
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222 | * monitoring the child and re-starting it after a delay if it exits
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223 | * abnormally. */
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224 | for (;;)
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225 | {
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226 | int iStatus, rcWait;
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227 |
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228 | pid = fork();
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229 | if (pid == -1)
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230 | return RTErrConvertFromErrno(errno);
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231 | if (pid == 0)
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232 | return VINF_SUCCESS;
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233 | do
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234 | rcWait = waitpid(pid, &iStatus, 0);
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235 | while (rcWait == -1 && errno == EINTR);
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236 | if (rcWait == -1)
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237 | exit(1);
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238 | if (WIFEXITED(iStatus) && WEXITSTATUS(iStatus) == 0)
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239 | exit(0);
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240 | sleep(5);
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241 | }
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242 | return VINF_SUCCESS;
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243 | #endif
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244 | }
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245 |
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246 |
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247 | /**
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248 | * Creates a PID File and returns the open file descriptor.
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249 | *
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250 | * On DOS based system, file sharing (deny write) is used for locking the PID
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251 | * file.
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252 | *
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253 | * On Unix-y systems, an exclusive advisory lock is used for locking the PID
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254 | * file since the file sharing support is usually missing there.
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255 | *
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256 | * This API will overwrite any existing PID Files without a lock on them, on the
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257 | * assumption that they are stale files which an old process did not properly
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258 | * clean up.
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259 | *
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260 | * @returns IPRT status code.
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261 | * @param pszPath The path and filename to create the PID File under
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262 | * @param phFile Where to store the file descriptor of the open (and locked
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263 | * on Unix-y systems) PID File. On failure, or if another
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264 | * process owns the PID File, this will be set to NIL_RTFILE.
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265 | */
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266 | VBGLR3DECL(int) VbglR3PidFile(const char *pszPath, PRTFILE phFile)
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267 | {
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268 | AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
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269 | AssertPtrReturn(phFile, VERR_INVALID_PARAMETER);
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270 | *phFile = NIL_RTFILE;
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271 |
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272 | RTFILE hPidFile;
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273 | int rc = RTFileOpen(&hPidFile, pszPath,
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274 | RTFILE_O_READWRITE | RTFILE_O_OPEN_CREATE | RTFILE_O_DENY_WRITE
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275 | | (0644 << RTFILE_O_CREATE_MODE_SHIFT));
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276 | if (RT_SUCCESS(rc))
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277 | {
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278 | #if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
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279 | /** @todo using size 0 for locking means lock all on Posix.
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280 | * We should adopt this as our convention too, or something
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281 | * similar. */
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282 | rc = RTFileLock(hPidFile, RTFILE_LOCK_WRITE, 0, 0);
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283 | if (RT_FAILURE(rc))
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284 | RTFileClose(hPidFile);
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285 | else
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286 | #endif
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287 | {
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288 | char szBuf[256];
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289 | size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n",
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290 | RTProcSelf());
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291 | RTFileWrite(hPidFile, szBuf, cbPid, NULL);
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292 | *phFile = hPidFile;
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293 | }
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294 | }
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295 | return rc;
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296 | }
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297 |
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298 |
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299 | /**
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300 | * Close and remove an open PID File.
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301 | *
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302 | * @param pszPath The path to the PID File,
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303 | * @param hFile The handle for the file. NIL_RTFILE is ignored as usual.
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304 | */
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305 | VBGLR3DECL(void) VbglR3ClosePidFile(const char *pszPath, RTFILE hFile)
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306 | {
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307 | AssertPtrReturnVoid(pszPath);
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308 | if (hFile != NIL_RTFILE)
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309 | {
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310 | #if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
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311 | RTFileWriteAt(hFile, 0, "-1", 2, NULL);
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312 | #else
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313 | RTFileDelete(pszPath);
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314 | #endif
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315 | RTFileClose(hFile);
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316 | }
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317 | }
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318 |
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