+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/mount.h>
+
+#include "machine-id-setup.h"
+#include "macro.h"
+#include "util.h"
+#include "log.h"
+
+static int generate(char id[34]) {
+ int fd;
+ char buf[16];
+ char *p, *q;
+ ssize_t k;
+
+ assert(id);
+
+ /* First, try reading the D-Bus machine id, unless it is a symlink */
+ if ((fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) >= 0) {
+
+ k = loop_read(fd, id, 33, false);
+ close_nointr_nofail(fd);
+
+ if (k >= 32) {
+ id[32] = '\n';
+ id[33] = 0;
+
+ log_info("Initializing machine ID from D-Bus machine ID.");
+ return 0;
+ }
+ }
+
+ /* If that didn't work, generate a random machine id */
+ if ((fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
+ log_error("Failed to open /dev/urandom: %m");
+ return -errno;
+ }
+
+ k = loop_read(fd, buf, sizeof(buf), false);
+ close_nointr_nofail(fd);
+
+ if (k != sizeof(buf)) {
+ log_error("Failed to read /dev/urandom: %s", strerror(k < 0 ? -k : EIO));
+ return k < 0 ? (int) k : -EIO;
+ }
+
+ for (p = buf, q = id; p < buf + sizeof(buf); p++, q += 2) {
+ q[0] = hexchar(*p >> 4);
+ q[1] = hexchar(*p & 15);
+ }
+
+ id[32] = '\n';
+ id[33] = 0;
+
+ log_info("Initializing machine ID from random generator.");
+
+ return 0;
+}
+
+int machine_id_setup(void) {
+ int fd, r;
+ bool writable;
+ struct stat st;
+ char id[34]; /* 32 + \n + \0 */
+ mode_t m;
+
+ m = umask(0000);
+
+ if ((fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0644)) >= 0)
+ writable = true;
+ else {
+ if ((fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
+ umask(m);
+ log_error("Cannot open /etc/machine-id: %m");
+ return -errno;
+ }
+
+ writable = false;
+ }
+
+ umask(m);
+
+ if (fstat(fd, &st) < 0) {
+ log_error("fstat() failed: %m");
+ r = -errno;
+ goto finish;
+ }
+
+ if (S_ISREG(st.st_mode)) {
+ if (loop_read(fd, id, 32, false) >= 32) {
+ r = 0;
+ goto finish;
+ }
+ }
+
+ /* Hmm, so, the id currently stored is not useful, then let's
+ * generate one */
+
+ if ((r = generate(id)) < 0)
+ goto finish;
+
+ if (S_ISREG(st.st_mode) && writable) {
+ lseek(fd, 0, SEEK_SET);
+
+ if (loop_write(fd, id, 33, false) == 33) {
+ r = 0;
+ goto finish;
+ }
+ }
+
+ close_nointr_nofail(fd);
+ fd = -1;
+
+ /* Hmm, we couldn't write it? So let's write it to
+ * /dev/.systemd/machine-id as a replacement */
+
+ mkdir_p("/dev/.systemd", 0755);
+
+ if ((r = write_one_line_file("/dev/.systemd/machine-id", id)) < 0) {
+ log_error("Cannot write /dev/.systemd/machine-id: %s", strerror(-r));
+
+ unlink("/dev/.systemd/machine-id");
+ goto finish;
+ }
+
+ /* And now, let's mount it over */
+ r = mount("/dev/.systemd/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0;
+ unlink("/dev/.systemd/machine-id");
+
+ if (r < 0)
+ log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
+ else
+ log_info("Installed non-transient /etc/machine-id file.");
+
+finish:
+
+ if (fd >= 0)
+ close_nointr_nofail(fd);
+
+ return r;
+}
~ianmdlvl / elogind.git / commitdiff