--- /dev/null
+/*-*- 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 Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser 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 <systemd/sd-id128.h>
+
+#include "machine-id-setup.h"
+#include "macro.h"
+#include "util.h"
+#include "mkdir.h"
+#include "log.h"
+#include "virt.h"
+
+static int shorten_uuid(char destination[36], const char *source) {
+ unsigned i, j;
+
+ for (i = 0, j = 0; i < 36 && j < 32; i++) {
+ int t;
+
+ t = unhexchar(source[i]);
+ if (t < 0)
+ continue;
+
+ destination[j++] = hexchar(t);
+ }
+
+ if (i == 36 && j == 32) {
+ destination[32] = '\n';
+ destination[33] = 0;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int generate(char id[34]) {
+ int fd, r;
+ unsigned char *p;
+ sd_id128_t buf;
+ char *q;
+ ssize_t k;
+ const char *vm_id;
+
+ assert(id);
+
+ /* First, try reading the D-Bus machine id, unless it is a symlink */
+ fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd >= 0) {
+
+ k = loop_read(fd, id, 32, 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, see if we are running in qemu/kvm and a
+ * machine ID was passed in via -uuid on the qemu/kvm command
+ * line */
+
+ r = detect_vm(&vm_id);
+ if (r > 0 && streq(vm_id, "kvm")) {
+ char uuid[37];
+
+ fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd >= 0) {
+ k = loop_read(fd, uuid, 36, false);
+ close_nointr_nofail(fd);
+
+ if (k >= 36) {
+ r = shorten_uuid(id, uuid);
+ if (r >= 0) {
+ log_info("Initializing machine ID from KVM UUID");
+ return 0;
+ }
+ }
+ }
+ }
+
+ /* If that didn't work either, see if we are running in a
+ * container, and a machine ID was passed in via
+ * $container_uuid the way libvirt/LXC does it */
+
+ r = detect_container(NULL);
+ if (r > 0) {
+ FILE *f;
+
+ f = fopen("/proc/1/environ", "re");
+ if (f) {
+ bool done = false;
+
+ do {
+ char line[LINE_MAX];
+ unsigned i;
+
+ for (i = 0; i < sizeof(line)-1; i++) {
+ int c;
+
+ c = getc(f);
+ if (_unlikely_(c == EOF)) {
+ done = true;
+ break;
+ } else if (c == 0)
+ break;
+
+ line[i] = c;
+ }
+ line[i] = 0;
+
+ if (startswith(line, "container_uuid=") &&
+ strlen(line + 15) >= 36) {
+ r = shorten_uuid(id, line + 15);
+ if (r >= 0) {
+ log_info("Initializing machine ID from container UUID");
+ return 0;
+ }
+ }
+
+ } while (!done);
+
+ fclose(f);
+ }
+ }
+
+ /* If that didn't work, generate a random machine id */
+ r = sd_id128_randomize(&buf);
+ if (r < 0) {
+ log_error("Failed to open /dev/urandom: %s", strerror(-r));
+ return r;
+ }
+
+ for (p = buf.bytes, q = id; p < buf.bytes + 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);
+
+ /* We create this 0444, to indicate that this isn't really
+ * something you should ever modify. Of course, since the file
+ * will be owned by root it doesn't matter much, but maybe
+ * people look. */
+
+ fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
+ if (fd >= 0)
+ writable = true;
+ else {
+ fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (fd < 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 */
+
+ r = generate(id);
+ if (r < 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
+ * /run/machine-id as a replacement */
+
+ m = umask(0022);
+ r = write_one_line_file("/run/machine-id", id);
+ umask(m);
+
+ if (r < 0) {
+ log_error("Cannot write /run/machine-id: %s", strerror(-r));
+
+ unlink("/run/machine-id");
+ goto finish;
+ }
+
+ /* And now, let's mount it over */
+ r = mount("/run/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0;
+ if (r < 0) {
+ unlink("/run/machine-id");
+ log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
+ } else
+ log_info("Installed transient /etc/machine-id file.");
+
+finish:
+
+ if (fd >= 0)
+ close_nointr_nofail(fd);
+
+ return r;
+}
~ianmdlvl / elogind.git / blobdiff