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https://github.com/freebsd/freebsd-src.git
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Konstantin Belousov
4c9f648852
Since init become dynamically linked, reroot appeared to be broken because init copies itself into a transient tmpfs mount to continue controlling execution right after the reboot(REROOT) syscall. Because the binary is dynamically linked, it cannot be properly executed. Provide a minimal static binary 'reroot_seed' embedded into the init as byte stream, which performs what the 'init -r' did, namely, the second phase reroot. For the static build of init as part of the /rescue crunch, keep the inline reroot code. Reported and tested by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D58164
110 lines
3.3 KiB
C
110 lines
3.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Donn Seeley at Berkeley Software Design, Inc.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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
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* OR 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/param.h>
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#include <sys/mount.h>
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#include <sys/reboot.h>
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#include <sys/sysctl.h>
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#include <err.h>
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#include <kenv.h>
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#include <paths.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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static void emergency(const char *, ...) __printflike(1, 2);
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static void
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emergency(const char *message, ...)
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{
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va_list ap;
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va_start(ap, message);
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vsyslog(LOG_EMERG, message, ap);
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va_end(ap);
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}
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int
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main(void)
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{
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char init_path[PATH_MAX], *path, *path_component;
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size_t init_path_len;
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int nbytes, error;
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openlog("init", LOG_CONS, LOG_AUTH);
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/*
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* Ask the kernel to mount the new rootfs.
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*/
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error = reboot(RB_REROOT);
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if (error != 0) {
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emergency("RB_REBOOT failed: %m");
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_exit(1);
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}
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/*
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* Figure out where the destination init(8) binary is. Note that
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* the path could be different than what we've started with. Use
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* the value from kenv, if set, or the one from sysctl otherwise.
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* The latter defaults to a hardcoded value, but can be overridden
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* by a build time option.
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*/
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nbytes = kenv(KENV_GET, "init_path", init_path, sizeof(init_path));
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if (nbytes <= 0) {
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init_path_len = sizeof(init_path);
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error = sysctlbyname("kern.init_path",
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init_path, &init_path_len, NULL, 0);
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if (error != 0) {
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emergency("failed to retrieve kern.init_path: %m");
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_exit(1);
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}
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}
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/*
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* Repeat the init search logic from sys/kern/init_path.c
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*/
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path_component = init_path;
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while ((path = strsep(&path_component, ":")) != NULL) {
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/*
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* Execute init(8) from the new rootfs.
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*/
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execl(path, path, NULL);
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}
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emergency("cannot exec init from %s: %m", init_path);
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_exit(1);
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}
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