VBoxGuestR3LibDaemonize.cpp@ 98475

Last change on this file since 98475 was 98475, checked in by vboxsync, 2 years ago
Guest Library: Introduce VbglR3DaemonizeEx and VbglR3PidfileWait (build fix 2), bugref:10359.
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1	/** $Id: VBoxGuestR3LibDaemonize.cpp 98475 2023-02-03 19:27:47Z vboxsync $ */
2	/** @file
3	* VBoxGuestR3Lib - Ring-3 Support Library for VirtualBox guest additions, daemonize a process.
4	*/
5
6	/*
7	* Copyright (C) 2007-2023 Oracle and/or its affiliates.
8	*
9	* This file is part of VirtualBox base platform packages, as
10	* available from https://www.virtualbox.org.
11	*
12	* This program is free software; you can redistribute it and/or
13	* modify it under the terms of the GNU General Public License
14	* as published by the Free Software Foundation, in version 3 of the
15	* License.
16	*
17	* This program is distributed in the hope that it will be useful, but
18	* WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20	* General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, see <https://www.gnu.org/licenses>.
24	*
25	* The contents of this file may alternatively be used under the terms
26	* of the Common Development and Distribution License Version 1.0
27	* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28	* in the VirtualBox distribution, in which case the provisions of the
29	* CDDL are applicable instead of those of the GPL.
30	*
31	* You may elect to license modified versions of this file under the
32	* terms and conditions of either the GPL or the CDDL or both.
33	*
34	* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35	*/
36
37
38	/*********************************************************************************************************************************
39	* Header Files *
40	*********************************************************************************************************************************/
41	#if defined(RT_OS_OS2)
42	# define INCL_BASE
43	# define INCL_ERRORS
44	# include <os2.h>
45
46	# include <iprt/alloca.h>
47	# include <iprt/string.h>
48
49	#elif defined(RT_OS_WINDOWS)
50	# error "PORTME"
51
52	#else /* the unices */
53	# include <sys/types.h>
54	# include <sys/stat.h>
55	# include <sys/wait.h>
56	# include <stdio.h>
57	# include <fcntl.h>
58	# include <stdlib.h>
59	# include <unistd.h>
60	# include <signal.h>
61	# include <errno.h>
62	#endif
63
64	#include <iprt/process.h>
65	#include <iprt/string.h>
66	#include <VBox/err.h>
67	#include <VBox/log.h>
68
69	#include "VBoxGuestR3LibInternal.h"
70
71
72	/**
73	* Daemonize the process for running in the background.
74	*
75	* This is supposed to do the same job as the BSD daemon() call.
76	*
77	* @returns 0 on success
78	*
79	* @param fNoChDir Pass false to change working directory to root.
80	* @param fNoClose Pass false to redirect standard file streams to /dev/null.
81	* @param fRespawn Restart the daemonised process after five seconds if it
82	* terminates abnormally.
83	* @param pcRespawn Where to store a count of how often we have respawned,
84	* intended for avoiding error spamming. Optional.
85	* @param fReturnOnUpdate If True, this function will return control to caller when
86	* child process will terminate with exit code of VBGLR3EXITCODERELOAD,
87	* indicating that Guest Additions update has been started and this running
88	* process will be asked to be restarted by arrival of the next SIGUSR1
89	* signal (caller should wait for SIGUSR1). If False, this functions will
90	* never return, but rather exit() when child process terminates with
91	* exit code 0.
92	* @param pfUpdateStarted A flag which passed to caller if fReturnOnUpdate is True (can be NULL).
93	* @param szPidfile Optional path to parent process' pidfile (can be NULL).
94	* @param phPidfile Optional path to parent process' pidfile handle (can not be NULL if
95	* szPidfile was specified).
96	*
97	* @todo Use RTProcDaemonize instead of this.
98	* @todo Implement fRespawn on OS/2.
99	* @todo Make the respawn interval configurable. But not until someone
100	* actually needs that.
101	*/
102	VBGLR3DECL(int) VbglR3DaemonizeEx(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn,
103	bool fReturnOnUpdate, bool pfUpdateStarted, const char szPidfile,
104	RTFILE *phPidfile)
105	{
106	#if defined(RT_OS_OS2)
107	PPIB pPib;
108	PTIB pTib;
109	DosGetInfoBlocks(&pTib, &pPib);
110
111	RT_NOREF(fReturnOnUpdate);
112	RT_NOREF(pfUpdateStarted);
113	RT_NOREF(szPidfile);
114	RT_NOREF(phPidfile);
115
116	AssertRelease(!fRespawn);
117	/* Get the full path to the executable. */
118	char szExe[CCHMAXPATH];
119	APIRET rc = DosQueryModuleName(pPib->pib_hmte, sizeof(szExe), szExe);
120	if (rc)
121	return RTErrConvertFromOS2(rc);
122
123	/* calc the length of the command line. */
124	char *pch = pPib->pib_pchcmd;
125	size_t cch0 = strlen(pch);
126	pch += cch0 + 1;
127	size_t cch1 = strlen(pch);
128	pch += cch1 + 1;
129	char *pchArgs;
130	if (cch1 && *pch)
131	{
132	do pch = strchr(pch, '\0') + 1;
133	while (*pch);
134
135	size_t cchTotal = pch - pPib->pib_pchcmd;
136	pchArgs = (char *)alloca(cchTotal + sizeof("--daemonized\0\0"));
137	memcpy(pchArgs, pPib->pib_pchcmd, cchTotal - 1);
138	memcpy(pchArgs + cchTotal - 1, "--daemonized\0\0", sizeof("--daemonized\0\0"));
139	}
140	else
141	{
142	size_t cchTotal = pch - pPib->pib_pchcmd + 1;
143	pchArgs = (char *)alloca(cchTotal + sizeof(" --daemonized "));
144	memcpy(pchArgs, pPib->pib_pchcmd, cch0 + 1);
145	pch = pchArgs + cch0 + 1;
146	memcpy(pch, " --daemonized ", sizeof(" --daemonized ") - 1);
147	pch += sizeof(" --daemonized ") - 1;
148	if (cch1)
149	memcpy(pch, pPib->pib_pchcmd + cch0 + 1, cch1 + 2);
150	else
151	pch[0] = pch[1] = '\0';
152	}
153
154	/* spawn a detach process */
155	char szObj[128];
156	RESULTCODES ResCodes = { 0, 0 };
157	szObj[0] = '\0';
158	rc = DosExecPgm(szObj, sizeof(szObj), EXEC_BACKGROUND, (PCSZ)pchArgs, NULL, &ResCodes, (PCSZ)szExe);
159	if (rc)
160	{
161	/** @todo Change this to some standard log/print error?? */
162	/* VBoxServiceError("DosExecPgm failed with rc=%d and szObj='%s'\n", rc, szObj); */
163	return RTErrConvertFromOS2(rc);
164	}
165	DosExit(EXIT_PROCESS, 0);
166	return VERR_GENERAL_FAILURE;
167
168	#elif defined(RT_OS_WINDOWS)
169	# error "PORTME"
170
171	#else /* the unices */
172	/*
173	* Fork the child process in a new session and quit the parent.
174	*
175	* - fork once and create a new session (setsid). This will detach us
176	* from the controlling tty meaning that we won't receive the SIGHUP
177	* (or any other signal) sent to that session.
178	* - The SIGHUP signal is ignored because the session/parent may throw
179	* us one before we get to the setsid.
180	* - When the parent exit(0) we will become an orphan and re-parented to
181	* the init process.
182	* - Because of the Linux / System V semantics of assigning the controlling
183	* tty automagically when a session leader first opens a tty, we will
184	* fork() once more on Linux to get rid of the session leadership role.
185	*/
186
187	struct sigaction OldSigAct;
188	struct sigaction SigAct;
189	RT_ZERO(SigAct);
190	SigAct.sa_handler = SIG_IGN;
191	int rcSigAct = sigaction(SIGHUP, &SigAct, &OldSigAct);
192
193	pid_t pid = fork();
194	if (pid == -1)
195	return RTErrConvertFromErrno(errno);
196	if (pid != 0)
197	exit(0);
198
199	/*
200	* The orphaned child becomes is reparented to the init process.
201	* We create a new session for it (setsid), point the standard
202	* file descriptors to /dev/null, and change to the root directory.
203	*/
204	pid_t newpgid = setsid();
205	int SavedErrno = errno;
206	if (rcSigAct != -1)
207	sigaction(SIGHUP, &OldSigAct, NULL);
208	if (newpgid == -1)
209	return RTErrConvertFromErrno(SavedErrno);
210
211	if (!fNoClose)
212	{
213	/* Open stdin(0), stdout(1) and stderr(2) as /dev/null. */
214	int fd = open("/dev/null", O_RDWR);
215	if (fd == -1) /* paranoia */
216	{
217	close(STDIN_FILENO);
218	close(STDOUT_FILENO);
219	close(STDERR_FILENO);
220	fd = open("/dev/null", O_RDWR);
221	}
222	if (fd != -1)
223	{
224	dup2(fd, STDIN_FILENO);
225	dup2(fd, STDOUT_FILENO);
226	dup2(fd, STDERR_FILENO);
227	if (fd > 2)
228	close(fd);
229	}
230	}
231
232	if (!fNoChDir)
233	{
234	int rcShutUpGcc = chdir("/");
235	RT_NOREF_PV(rcShutUpGcc);
236	}
237
238	/*
239	* Change the umask - this is non-standard daemon() behavior.
240	*/
241	umask(027);
242
243	# ifdef RT_OS_LINUX
244	/*
245	* And fork again to lose session leader status (non-standard daemon()
246	* behaviour).
247	*/
248	pid = fork();
249	if (pid == -1)
250	return RTErrConvertFromErrno(errno);
251	if (pid != 0)
252	exit(0);
253	# endif /* RT_OS_LINUX */
254
255	/* Check if another instance is already running. */
256	if (szPidfile != NULL)
257	{
258	if (phPidfile != NULL)
259	{
260	int rc = VbglR3PidfileWait(szPidfile, phPidfile, 5000);
261
262	/* Another instance of process is already running. */
263	if (rc == VERR_FILE_LOCK_VIOLATION)
264	{
265	LogRel(("cannot aquire pidfile %s, exitting\n", szPidfile));
266	exit(1);
267	}
268
269	/* Unable to lock on pidfile. */
270	if (RT_FAILURE(rc))
271	exit(1);
272	}
273	else
274	return VERR_INVALID_PARAMETER;
275	}
276
277	if (fRespawn)
278	{
279	/* We implement re-spawning as a third fork(), with the parent process
280	* monitoring the child and re-starting it after a delay if it exits
281	* abnormally. */
282	unsigned cRespawn = 0;
283	for (;;)
284	{
285	int iStatus, rcWait;
286
287	if (pcRespawn != NULL)
288	*pcRespawn = cRespawn;
289	pid = fork();
290	if (pid == -1)
291	return RTErrConvertFromErrno(errno);
292	if (pid == 0)
293	return VINF_SUCCESS;
294	do
295	rcWait = waitpid(pid, &iStatus, 0);
296	while (rcWait == -1 && errno == EINTR);
297	if (rcWait == -1)
298	exit(1);
299	if (WIFEXITED(iStatus))
300	{
301	if (WEXITSTATUS(iStatus) == 0)
302	exit(0);
303	else if (fReturnOnUpdate && WEXITSTATUS(iStatus) == VBGLR3EXITCODERELOAD)
304	{
305	/* Tell caller that update has been started. */
306	if (pfUpdateStarted != NULL)
307	*pfUpdateStarted = true;
308
309	return VINF_SUCCESS;
310	}
311	}
312	sleep(5);
313	++cRespawn;
314	}
315	}
316	return VINF_SUCCESS;
317	#endif
318	}
319
320	/**
321	* A wrapper function for VbglR3DaemonizeEx.
322	*/
323	VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn)
324	{
325	return VbglR3DaemonizeEx(fNoChDir, fNoClose, fRespawn, pcRespawn, false, NULL, NULL, NULL);
326	}

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source: vbox/trunk/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibDaemonize.cpp@ 98475

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