diff options
Diffstat (limited to 'src/core/machine-id-setup.c')
| -rw-r--r-- | src/core/machine-id-setup.c | 224 |
1 files changed, 59 insertions, 165 deletions
diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c index ea6b085e4f..76dfcfa6d7 100644 --- a/src/core/machine-id-setup.c +++ b/src/core/machine-id-setup.c @@ -17,11 +17,8 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ -#include <errno.h> #include <fcntl.h> #include <sched.h> -#include <stdio.h> -#include <string.h> #include <sys/mount.h> #include <unistd.h> @@ -29,10 +26,8 @@ #include "alloc-util.h" #include "fd-util.h" -#include "fileio.h" #include "fs-util.h" -#include "hexdecoct.h" -#include "io-util.h" +#include "id128-util.h" #include "log.h" #include "machine-id-setup.h" #include "macro.h" @@ -46,101 +41,23 @@ #include "util.h" #include "virt.h" -static int shorten_uuid(char destination[34], const char source[36]) { - unsigned i, j; - - assert(destination); - assert(source); - - /* Converts a UUID into a machine ID, by lowercasing it and - * removing dashes. Validates everything. */ - - 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) - return -EINVAL; - - destination[32] = '\n'; - destination[33] = 0; - return 0; -} - -static int read_machine_id(int fd, char id[34]) { - char id_to_validate[34]; - int r; - - assert(fd >= 0); - assert(id); - - /* Reads a machine ID from a file, validates it, and returns - * it. The returned ID ends in a newline. */ - - r = loop_read_exact(fd, id_to_validate, 33, false); - if (r < 0) - return r; - - if (id_to_validate[32] != '\n') - return -EINVAL; - - id_to_validate[32] = 0; - - if (!id128_is_valid(id_to_validate)) - return -EINVAL; - - memcpy(id, id_to_validate, 32); - id[32] = '\n'; - id[33] = 0; - return 0; -} - -static int write_machine_id(int fd, const char id[34]) { - int r; - - assert(fd >= 0); - assert(id); - - if (lseek(fd, 0, SEEK_SET) < 0) - return -errno; - - r = loop_write(fd, id, 33, false); - if (r < 0) - return r; - - if (fsync(fd) < 0) - return -errno; - - return 0; -} - -static int generate_machine_id(char id[34], const char *root) { - int fd, r; - unsigned char *p; - sd_id128_t buf; - char *q; +static int generate_machine_id(const char *root, sd_id128_t *ret) { const char *dbus_machine_id; + _cleanup_close_ int fd = -1; + int r; - assert(id); - - dbus_machine_id = prefix_roota(root, "/var/lib/dbus/machine-id"); + assert(ret); /* First, try reading the D-Bus machine id, unless it is a symlink */ + dbus_machine_id = prefix_roota(root, "/var/lib/dbus/machine-id"); fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fd >= 0) { - r = read_machine_id(fd, id); - safe_close(fd); - - if (r >= 0) { + if (id128_read_fd(fd, ID128_PLAIN, ret) >= 0) { log_info("Initializing machine ID from D-Bus machine ID."); return 0; } + + fd = safe_close(fd); } if (isempty(root)) { @@ -151,13 +68,10 @@ static int generate_machine_id(char id[34], const char *root) { if (detect_container() > 0) { _cleanup_free_ char *e = NULL; - r = getenv_for_pid(1, "container_uuid", &e); - if (r > 0) { - r = shorten_uuid(id, e); - if (r >= 0) { - log_info("Initializing machine ID from container UUID."); - return 0; - } + if (getenv_for_pid(1, "container_uuid", &e) > 0 && + sd_id128_from_string(e, ret) >= 0) { + log_info("Initializing machine ID from container UUID."); + return 0; } } else if (detect_vm() == VIRTUALIZATION_KVM) { @@ -166,51 +80,29 @@ static int generate_machine_id(char id[34], const char *root) { * running in qemu/kvm and a machine ID was passed in * via -uuid on the qemu/kvm command line */ - char uuid[36]; - - fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); - if (fd >= 0) { - r = loop_read_exact(fd, uuid, 36, false); - safe_close(fd); - - if (r >= 0) { - r = shorten_uuid(id, uuid); - if (r >= 0) { - log_info("Initializing machine ID from KVM UUID."); - return 0; - } - } + if (id128_read("/sys/class/dmi/id/product_uuid", ID128_UUID, ret) >= 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); + r = sd_id128_randomize(ret); 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); - q[1] = hexchar(*p & 15); - } - - id[32] = '\n'; - id[33] = 0; + return log_error_errno(r, "Failed to generate randomized : %m"); log_info("Initializing machine ID from random generator."); - return 0; } -int machine_id_setup(const char *root, sd_id128_t machine_id) { +int machine_id_setup(const char *root, sd_id128_t machine_id, sd_id128_t *ret) { const char *etc_machine_id, *run_machine_id; _cleanup_close_ int fd = -1; - bool writable = true; - char id[34]; /* 32 + \n + \0 */ + bool writable; int r; etc_machine_id = prefix_roota(root, "/etc/machine-id"); - run_machine_id = prefix_roota(root, "/run/machine-id"); RUN_WITH_UMASK(0000) { /* We create this 0444, to indicate that this isn't really @@ -218,7 +110,7 @@ int machine_id_setup(const char *root, sd_id128_t machine_id) { * will be owned by root it doesn't matter much, but maybe * people look. */ - mkdir_parents(etc_machine_id, 0755); + (void) mkdir_parents(etc_machine_id, 0755); fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); if (fd < 0) { int old_errno = errno; @@ -239,41 +131,41 @@ int machine_id_setup(const char *root, sd_id128_t machine_id) { } writable = false; - } + } else + writable = true; } - /* A machine id argument overrides all other machined-ids */ - if (!sd_id128_is_null(machine_id)) { - sd_id128_to_string(machine_id, id); - id[32] = '\n'; - id[33] = 0; - } else { - if (read_machine_id(fd, id) >= 0) - return 0; + /* A we got a valid machine ID argument, that's what counts */ + if (sd_id128_is_null(machine_id)) { - /* Hmm, so, the id currently stored is not useful, then let's - * generate one */ + /* Try to read any existing machine ID */ + if (id128_read_fd(fd, ID128_PLAIN, ret) >= 0) + return 0; - r = generate_machine_id(id, root); + /* Hmm, so, the id currently stored is not useful, then let's generate one */ + r = generate_machine_id(root, &machine_id); if (r < 0) return r; + + if (lseek(fd, 0, SEEK_SET) == (off_t) -1) + return log_error_errno(errno, "Failed to seek: %m"); } if (writable) - if (write_machine_id(fd, id) >= 0) - return 0; + if (id128_write_fd(fd, ID128_PLAIN, machine_id, true) >= 0) + goto finish; fd = safe_close(fd); - /* Hmm, we couldn't write it? So let's write it to - * /run/machine-id as a replacement */ + /* 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, WRITE_STRING_FILE_CREATE); - if (r < 0) { - (void) unlink(run_machine_id); - return log_error_errno(r, "Cannot write %s: %m", run_machine_id); - } + run_machine_id = prefix_roota(root, "/run/machine-id"); + + RUN_WITH_UMASK(0022) + r = id128_write(run_machine_id, ID128_PLAIN, machine_id, false); + if (r < 0) { + (void) unlink(run_machine_id); + return log_error_errno(r, "Cannot write %s: %m", run_machine_id); } /* And now, let's mount it over */ @@ -286,7 +178,11 @@ int machine_id_setup(const char *root, sd_id128_t machine_id) { /* Mark the mount read-only */ if (mount(NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0) - log_warning_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id); + log_warning_errno(errno, "Failed to make transient %s read-only, ignoring: %m", etc_machine_id); + +finish: + if (ret) + *ret = machine_id; return 0; } @@ -294,9 +190,13 @@ int machine_id_setup(const char *root, sd_id128_t machine_id) { int machine_id_commit(const char *root) { _cleanup_close_ int fd = -1, initial_mntns_fd = -1; const char *etc_machine_id; - char id[34]; /* 32 + \n + \0 */ + sd_id128_t id; int r; + /* Replaces a tmpfs bind mount of /etc/machine-id by a proper file, atomically. For this, the umount is removed + * in a mount namespace, a new file is created at the right place. Afterwards the mount is also removed in the + * original mount namespace, thus revealing the file that was just created. */ + etc_machine_id = prefix_roota(root, "/etc/machine-id"); r = path_is_mount_point(etc_machine_id, 0); @@ -312,10 +212,6 @@ int machine_id_commit(const char *root) { if (fd < 0) return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); - r = read_machine_id(fd, id); - if (r < 0) - return log_error_errno(r, "We didn't find a valid machine ID in %s.", etc_machine_id); - r = fd_is_temporary_fs(fd); if (r < 0) return log_error_errno(r, "Failed to determine whether %s is on a temporary file system: %m", etc_machine_id); @@ -324,6 +220,10 @@ int machine_id_commit(const char *root) { return -EROFS; } + r = id128_read_fd(fd, ID128_PLAIN, &id); + if (r < 0) + return log_error_errno(r, "We didn't find a valid machine ID in %s.", etc_machine_id); + fd = safe_close(fd); /* Store current mount namespace */ @@ -342,15 +242,9 @@ int machine_id_commit(const char *root) { return log_error_errno(errno, "Failed to unmount transient %s file in our private namespace: %m", etc_machine_id); /* Update a persistent version of etc_machine_id */ - fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); - if (fd < 0) - return log_error_errno(errno, "Cannot open for writing %s. This is mandatory to get a persistent machine-id: %m", etc_machine_id); - - r = write_machine_id(fd, id); + r = id128_write(etc_machine_id, ID128_PLAIN, id, true); if (r < 0) - return log_error_errno(r, "Cannot write %s: %m", etc_machine_id); - - fd = safe_close(fd); + return log_error_errno(r, "Cannot write %s. This is mandatory to get a persistent machine ID: %m", etc_machine_id); /* Return to initial namespace and proceed a lazy tmpfs unmount */ r = namespace_enter(-1, initial_mntns_fd, -1, -1, -1); |