125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
/* $NetBSD: rumpuser_daemonize.c,v 1.2 2011/01/22 14:18:55 pooka Exp $ */
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/*
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* Copyright (c) 2010 Antti Kantee. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if !defined(lint)
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__RCSID("$NetBSD: rumpuser_daemonize.c,v 1.2 2011/01/22 14:18:55 pooka Exp $");
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#endif /* !lint */
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <stdio.h>
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#include <unistd.h>
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static int isdaemonizing;
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static int daemonpipe[2];
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#include <rump/rumpuser.h>
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int
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rumpuser_daemonize_begin(void)
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{
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ssize_t n;
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int error;
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if (isdaemonizing)
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return EINPROGRESS;
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isdaemonizing = 1;
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/*
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* For daemons we need to fork. However, since we can't fork
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* after rump_init (which creates threads), do it now. Add
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* a little pipe trickery to make sure we don't exit until the
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* service is fully inited (i.e. interlocked daemonization).
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* Actually, use sucketpair since that allows to easily steer
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* clear of the dreaded sigpipe.
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*
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* Note: We do *NOT* host chdir("/"). It's up to the caller to
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* take care of that or not.
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*/
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if (socketpair(PF_LOCAL, SOCK_STREAM, 0, daemonpipe) == -1) {
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return errno;
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}
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switch (fork()) {
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case 0:
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if (setsid() == -1) {
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rumpuser_daemonize_done(errno);
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}
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return 0;
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case -1:
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return errno;
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default:
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close(daemonpipe[1]);
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n = recv(daemonpipe[0], &error, sizeof(error), MSG_NOSIGNAL);
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if (n == -1)
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error = errno;
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else if (n != sizeof(error))
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error = ESRCH;
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_exit(error);
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/*NOTREACHED*/
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}
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}
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int
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rumpuser_daemonize_done(int error)
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{
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ssize_t n;
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int fd;
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if (!isdaemonizing)
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return ENOENT;
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if (error == 0) {
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fd = open(_PATH_DEVNULL, O_RDWR);
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if (fd == -1) {
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error = errno;
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goto out;
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}
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dup2(fd, STDIN_FILENO);
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dup2(fd, STDOUT_FILENO);
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dup2(fd, STDERR_FILENO);
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if (fd > STDERR_FILENO)
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close(fd);
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}
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out:
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n = send(daemonpipe[1], &error, sizeof(error), MSG_NOSIGNAL);
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if (n != sizeof(error))
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return EPIPE;
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else if (n == -1)
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return errno;
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close(daemonpipe[0]);
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close(daemonpipe[1]);
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return 0;
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}
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