X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fmachine-id-setup.c;h=0f97433804e5fa6d7cec6baa259956ec396f6988;hp=0ec61924492e3060321f4e745243264f29de0c8c;hb=64661ee70d5a10c6208a1cb66ecd8b158e2d8bc5;hpb=9b4f818bd8dd45029992f844d07a61c9977da720 diff --git a/src/machine-id-setup.c b/src/machine-id-setup.c index 0ec619244..0f9743380 100644 --- a/src/machine-id-setup.c +++ b/src/machine-id-setup.c @@ -27,23 +27,51 @@ #include #include +#include + #include "machine-id-setup.h" #include "macro.h" #include "util.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; - char buf[16]; - char *p, *q; + 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 */ - if ((fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) >= 0) { + 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); + k = loop_read(fd, id, 32, false); close_nointr_nofail(fd); if (k >= 32) { @@ -55,21 +83,82 @@ static int generate(char id[34]) { } } - /* 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; + /* 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; + } + } + } } - k = loop_read(fd, buf, sizeof(buf), false); - close_nointr_nofail(fd); + /* 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; - if (k != sizeof(buf)) { - log_error("Failed to read /dev/urandom: %s", strerror(k < 0 ? -k : EIO)); - return k < 0 ? (int) k : -EIO; + 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); + } } - for (p = buf, q = id; p < buf + sizeof(buf); p++, q += 2) { + /* 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); } @@ -91,10 +180,17 @@ int machine_id_setup(void) { m = umask(0000); - if ((fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0644)) >= 0) + /* 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 { - if ((fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) { + 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; @@ -121,7 +217,8 @@ int machine_id_setup(void) { /* Hmm, so, the id currently stored is not useful, then let's * generate one */ - if ((r = generate(id)) < 0) + r = generate(id); + if (r < 0) goto finish; if (S_ISREG(st.st_mode) && writable) { @@ -137,20 +234,24 @@ int machine_id_setup(void) { fd = -1; /* Hmm, we couldn't write it? So let's write it to - * /dev/.systemd/machine-id as a replacement */ + * /run/systemd/machine-id as a replacement */ + + mkdir_p("/run/systemd", 0755); - mkdir_p("/dev/.systemd", 0755); + m = umask(0022); + r = write_one_line_file("/run/systemd/machine-id", id); + umask(m); - if ((r = write_one_line_file("/dev/.systemd/machine-id", id)) < 0) { - log_error("Cannot write /dev/.systemd/machine-id: %s", strerror(-r)); + if (r < 0) { + log_error("Cannot write /run/systemd/machine-id: %s", strerror(-r)); - unlink("/dev/.systemd/machine-id"); + unlink("/run/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"); + r = mount("/run/systemd/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0; + unlink("/run/systemd/machine-id"); if (r < 0) log_error("Failed to mount /etc/machine-id: %s", strerror(-r));