2b583ce657
Instead of the /dev/.run trick we have currently implemented, we decided to move the early-boot runtime dir to /run. An existing /var/run directory is bind-mounted to /run. If /var/run is already a symlink, no action is taken. An existing /var/lock directory is bind-mounted to /run/lock. If /var/lock is already a symlink, no action is taken. To implement the directory vs. symlink logic, we have a: ConditionPathIsDirectory= now, which is used in the mount units. Skipped mount unit in case of symlink: $ systemctl status var-run.mount var-run.mount - Runtime Directory Loaded: loaded (/lib/systemd/system/var-run.mount) Active: inactive (dead) start condition failed at Fri, 25 Mar 2011 04:51:41 +0100; 6min ago Where: /var/run What: /run CGroup: name=systemd:/system/var-run.mount The systemd rpm needs to make sure to add something like: %pre mkdir -p -m0755 /run >/dev/null 2>&1 || : or it needs to be added to filesystem.rpm. Udev -git already uses /run if that exists, and is writable at bootup. Otherwise it falls back to the current /dev/.udev. Dracut and plymouth need to be adopted to switch from /dev/.run to run too. Cheers, Kay
172 lines
4.9 KiB
C
172 lines
4.9 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <unistd.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/mount.h>
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#include "machine-id-setup.h"
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#include "macro.h"
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#include "util.h"
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#include "log.h"
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static int generate(char id[34]) {
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int fd;
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char buf[16];
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char *p, *q;
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ssize_t k;
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assert(id);
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/* First, try reading the D-Bus machine id, unless it is a symlink */
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if ((fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) >= 0) {
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k = loop_read(fd, id, 33, false);
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close_nointr_nofail(fd);
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if (k >= 32) {
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id[32] = '\n';
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id[33] = 0;
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log_info("Initializing machine ID from D-Bus machine ID.");
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return 0;
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}
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}
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/* If that didn't work, generate a random machine id */
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if ((fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
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log_error("Failed to open /dev/urandom: %m");
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return -errno;
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}
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k = loop_read(fd, buf, sizeof(buf), false);
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close_nointr_nofail(fd);
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if (k != sizeof(buf)) {
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log_error("Failed to read /dev/urandom: %s", strerror(k < 0 ? -k : EIO));
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return k < 0 ? (int) k : -EIO;
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}
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for (p = buf, q = id; p < buf + sizeof(buf); p++, q += 2) {
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q[0] = hexchar(*p >> 4);
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q[1] = hexchar(*p & 15);
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}
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id[32] = '\n';
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id[33] = 0;
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log_info("Initializing machine ID from random generator.");
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return 0;
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}
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int machine_id_setup(void) {
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int fd, r;
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bool writable;
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struct stat st;
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char id[34]; /* 32 + \n + \0 */
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mode_t m;
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m = umask(0000);
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/* We create this 0444, to indicate that this isn't really
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* something you should ever modify. Of course, since the file
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* will be owned by root it doesn't matter much, but maybe
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* people look. */
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if ((fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444)) >= 0)
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writable = true;
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else {
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if ((fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
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umask(m);
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log_error("Cannot open /etc/machine-id: %m");
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return -errno;
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}
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writable = false;
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}
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umask(m);
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if (fstat(fd, &st) < 0) {
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log_error("fstat() failed: %m");
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r = -errno;
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goto finish;
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}
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if (S_ISREG(st.st_mode)) {
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if (loop_read(fd, id, 32, false) >= 32) {
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r = 0;
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goto finish;
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}
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}
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/* Hmm, so, the id currently stored is not useful, then let's
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* generate one */
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if ((r = generate(id)) < 0)
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goto finish;
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if (S_ISREG(st.st_mode) && writable) {
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lseek(fd, 0, SEEK_SET);
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if (loop_write(fd, id, 33, false) == 33) {
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r = 0;
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goto finish;
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}
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}
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close_nointr_nofail(fd);
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fd = -1;
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/* Hmm, we couldn't write it? So let's write it to
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* /run/systemd/machine-id as a replacement */
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mkdir_p("/run/systemd", 0755);
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if ((r = write_one_line_file("/run/systemd/machine-id", id)) < 0) {
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log_error("Cannot write /run/systemd/machine-id: %s", strerror(-r));
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unlink("/run/systemd/machine-id");
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goto finish;
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}
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/* And now, let's mount it over */
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r = mount("/run/systemd/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0;
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unlink("/run/systemd/machine-id");
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if (r < 0)
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log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
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else
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log_info("Installed transient /etc/machine-id file.");
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finish:
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if (fd >= 0)
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close_nointr_nofail(fd);
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return r;
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}
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