X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fcore%2Fmachine-id-setup.c;h=d8600bde2ddd9b1ab361923507ceaebd2a12a8f4;hb=3543f8218b732132dff6d0dccb2ce357e4154801;hp=712f60cb11c6ab0661a97a8f1ba8578dfde69567;hpb=73f860db9893deab6aebceb53dd7d0deb662e832;p=elogind.git diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c index 712f60cb1..d8600bde2 100644 --- a/src/core/machine-id-setup.c +++ b/src/core/machine-id-setup.c @@ -64,15 +64,16 @@ static int generate(char id[34], const char *root) { int fd, r; unsigned char *p; sd_id128_t buf; - char *q; + char *q; ssize_t k; - const char *vm_id; - _cleanup_free_ char *dbus_machine_id = NULL; + const char *vm_id, *dbus_machine_id; assert(id); - if (asprintf(&dbus_machine_id, "%s/var/lib/dbus/machine-id", root) < 0) - return log_oom(); + if (isempty(root)) + dbus_machine_id = "/var/lib/dbus/machine-id"; + else + dbus_machine_id = strappenda(root, "/var/lib/dbus/machine-id"); /* First, try reading the D-Bus machine id, unless it is a symlink */ fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); @@ -93,55 +94,55 @@ static int generate(char id[34], const char *root) { } } - /* If that didn't work, 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 (isempty(root)) { + /* If that didn't work, 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) { - if (strlen(e) >= 36) { - r = shorten_uuid(id, e); - if (r >= 0) { - log_info("Initializing machine ID from container UUID."); - return 0; - } - } - } - - } else { - /* If we are not running in a container, see if we are - * running in qemu/kvm and a machine ID was passed in - * via -uuid on the qemu/kvm command line */ + _cleanup_free_ char *e = NULL; - 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); - safe_close(fd); - - if (k >= 36) { - r = shorten_uuid(id, uuid); + 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 KVM UUID."); + log_info("Initializing machine ID from container UUID."); return 0; } } } + + } else { + /* If we are not running in a container, 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); + safe_close(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, 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; - } + if (r < 0) + return log_error_errno(r, "Failed to open /dev/urandom: %m"); for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) { q[0] = hexchar(*p >> 4); @@ -156,10 +157,41 @@ static int generate(char id[34], const char *root) { return 0; } +static int get_valid_machine_id(int fd, char id[34]) { + char id_to_validate[34]; + + assert(fd >= 0); + assert(id); + + if (loop_read(fd, id_to_validate, 33, false) == 33 && id_to_validate[32] == '\n') { + id_to_validate[32] = 0; + + if (id128_is_valid(id_to_validate)) { + memcpy(id, id_to_validate, 32); + id[32] = '\n'; + id[33] = 0; + return 0; + } + } + + return -EINVAL; +} + +static int write_machine_id(int fd, char id[34]) { + assert(fd >= 0); + assert(id); + lseek(fd, 0, SEEK_SET); + + if (loop_write(fd, id, 33, false) == 33) + return 0; + + return -errno; +} + int machine_id_setup(const char *root) { const char *etc_machine_id, *run_machine_id; _cleanup_close_ int fd = -1; - bool writable = false; + bool writable = true; struct stat st; char id[34]; /* 32 + \n + \0 */ int r; @@ -168,11 +200,13 @@ int machine_id_setup(const char *root) { etc_machine_id = "/etc/machine-id"; run_machine_id = "/run/machine-id"; } else { - etc_machine_id = strappenda(root, "/etc/machine-id"); - path_kill_slashes((char*) etc_machine_id); + char *x; - run_machine_id = strappenda(root, "/run/machine-id"); - path_kill_slashes((char*) run_machine_id); + x = strappenda(root, "/etc/machine-id"); + etc_machine_id = path_kill_slashes(x); + + x = strappenda(root, "/run/machine-id"); + run_machine_id = path_kill_slashes(x); } RUN_WITH_UMASK(0000) { @@ -183,12 +217,19 @@ int machine_id_setup(const char *root) { mkdir_parents(etc_machine_id, 0755); fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); - if (fd >= 0) - writable = true; - else { + if (fd < 0) { + int old_errno = errno; + fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fd < 0) { - log_error("Cannot open %s: %m", etc_machine_id); + if (old_errno == EROFS && errno == ENOENT) + log_error("System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n" + "Booting up is supported only when:\n" + "1) /etc/machine-id exists and is populated.\n" + "2) /etc/machine-id exists and is empty.\n" + "3) /etc/machine-id is missing and /etc is writable.\n"); + else + log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); return -errno; } @@ -196,18 +237,11 @@ int machine_id_setup(const char *root) { } } - 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 (fstat(fd, &st) < 0) + return log_error_errno(errno, "fstat() failed: %m"); - if (id128_is_valid(id)) - return 0; - } + if (S_ISREG(st.st_mode) && get_valid_machine_id(fd, id) == 0) + return 0; /* Hmm, so, the id currently stored is not useful, then let's * generate one */ @@ -217,9 +251,7 @@ int machine_id_setup(const char *root) { return r; if (S_ISREG(st.st_mode) && writable) { - lseek(fd, 0, SEEK_SET); - - if (loop_write(fd, id, 33, false) == 33) + if (write_machine_id(fd, id) == 0) return 0; } @@ -232,7 +264,7 @@ int machine_id_setup(const char *root) { r = write_string_file(run_machine_id, id); } if (r < 0) { - log_error("Cannot write %s: %s", run_machine_id, strerror(-r)); + log_error_errno(r, "Cannot write %s: %m", run_machine_id); unlink(run_machine_id); return r; } @@ -240,7 +272,7 @@ int machine_id_setup(const char *root) { /* 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 %s: %m", etc_machine_id); + log_error_errno(errno, "Failed to mount %s: %m", etc_machine_id); unlink_noerrno(run_machine_id); return -errno; } @@ -249,7 +281,7 @@ int machine_id_setup(const char *root) { /* 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 %s read-only: %m", etc_machine_id); + log_warning_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id); return 0; }