| /*-*- 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" |
| #include "fileio.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, 33, false); |
| close_nointr_nofail(fd); |
| |
| if (k == 33 && id[32] == '\n') { |
| |
| id[32] = 0; |
| if (id128_is_valid(id)) { |
| 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) { |
| _cleanup_free_ char *e = NULL; |
| |
| r = getenv_for_pid(1, "container_uuid", &e); |
| if (r > 0) { |
| if (strlen(e) >= 36) { |
| r = shorten_uuid(id, e); |
| if (r >= 0) { |
| log_info("Initializing machine ID from container UUID."); |
| return 0; |
| } |
| } |
| } |
| } |
| |
| /* 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) { |
| _cleanup_close_ int fd = -1; |
| int r; |
| bool writable = false; |
| struct stat st; |
| char id[34]; /* 32 + \n + \0 */ |
| |
| RUN_WITH_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) { |
| log_error("Cannot open /etc/machine-id: %m"); |
| return -errno; |
| } |
| |
| writable = false; |
| } |
| } |
| |
| if (fstat(fd, &st) < 0) { |
| log_error("fstat() failed: %m"); |
| return -errno; |
| } |
| |
| if (S_ISREG(st.st_mode)) |
| if (loop_read(fd, id, 33, false) == 33 && id[32] == '\n') { |
| id[32] = 0; |
| |
| if (id128_is_valid(id)) |
| return 0; |
| } |
| |
| /* Hmm, so, the id currently stored is not useful, then let's |
| * generate one */ |
| |
| r = generate(id); |
| if (r < 0) |
| return r; |
| |
| if (S_ISREG(st.st_mode) && writable) { |
| lseek(fd, 0, SEEK_SET); |
| |
| if (loop_write(fd, id, 33, false) == 33) |
| return 0; |
| } |
| |
| close_nointr_nofail(fd); |
| fd = -1; |
| |
| /* Hmm, we couldn't write it? So let's write it to |
| * /run/machine-id as a replacement */ |
| |
| RUN_WITH_UMASK(0022) { |
| r = write_string_file("/run/machine-id", id); |
| } |
| if (r < 0) { |
| log_error("Cannot write /run/machine-id: %s", strerror(-r)); |
| unlink("/run/machine-id"); |
| return r; |
| } |
| |
| /* And now, let's mount it over */ |
| r = mount("/run/machine-id", "/etc/machine-id", NULL, MS_BIND, NULL); |
| if (r < 0) { |
| log_error("Failed to mount /etc/machine-id: %m"); |
| unlink_noerrno("/run/machine-id"); |
| return -errno; |
| } |
| |
| log_info("Installed transient /etc/machine-id file."); |
| |
| /* Mark the mount read-only */ |
| if (mount(NULL, "/etc/machine-id", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0) |
| log_warning("Failed to make transient /etc/machine-id read-only: %m"); |
| |
| return 0; |
| } |