#include <stdio.h>
#include <errno.h>
#include <string.h>
-#include <stdlib.h>
#include <fcntl.h>
#include <sys/mount.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;
destination[j++] = hexchar(t);
}
- if (i == 36 && j == 32) {
- destination[32] = '\n';
- destination[33] = 0;
- return 0;
- }
+ 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, char id[34]) {
+ assert(fd >= 0);
+ assert(id);
- return -EINVAL;
+ if (lseek(fd, 0, SEEK_SET) < 0)
+ return -errno;
+
+ return loop_write(fd, id, 33, false);
}
-static int generate(char id[34], const char *root) {
+static int generate_machine_id(char id[34], const char *root) {
int fd, r;
unsigned char *p;
sd_id128_t buf;
char *q;
- ssize_t k;
const char *vm_id, *dbus_machine_id;
assert(id);
if (isempty(root))
dbus_machine_id = "/var/lib/dbus/machine-id";
else
- dbus_machine_id = strappenda(root, "/var/lib/dbus/machine-id");
+ dbus_machine_id = strjoina(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);
if (fd >= 0) {
- k = loop_read(fd, id, 33, false);
+ r = read_machine_id(fd, id);
safe_close(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 (r >= 0) {
+ log_info("Initializing machine ID from D-Bus machine ID.");
+ return 0;
}
}
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;
- }
+ r = shorten_uuid(id, e);
+ if (r >= 0) {
+ log_info("Initializing machine ID from container UUID.");
+ return 0;
}
}
r = detect_vm(&vm_id);
if (r > 0 && streq(vm_id, "kvm")) {
- char uuid[37];
+ char uuid[36];
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);
+ r = loop_read_exact(fd, uuid, 36, false);
safe_close(fd);
- if (k >= 36) {
+ if (r >= 0) {
r = shorten_uuid(id, uuid);
if (r >= 0) {
log_info("Initializing machine ID from KVM UUID.");
/* 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);
const char *etc_machine_id, *run_machine_id;
_cleanup_close_ int fd = -1;
bool writable = true;
- struct stat st;
char id[34]; /* 32 + \n + \0 */
int r;
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;
+
+ x = strjoina(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
- run_machine_id = strappenda(root, "/run/machine-id");
- path_kill_slashes((char*) run_machine_id);
+ x = strjoina(root, "/run/machine-id");
+ run_machine_id = path_kill_slashes(x);
}
RUN_WITH_UMASK(0000) {
fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (old_errno == EROFS && errno == ENOENT)
- log_error("System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n"
+ log_error_errno(errno,
+ "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("Cannot open %s: %m", etc_machine_id);
+ log_error_errno(errno, "Cannot open %s: %m", etc_machine_id);
+
return -errno;
}
}
}
- 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;
- }
+ if (read_machine_id(fd, id) >= 0)
+ return 0;
/* Hmm, so, the id currently stored is not useful, then let's
* generate one */
- r = generate(id, root);
+ r = generate_machine_id(id, root);
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)
+ if (writable)
+ if (write_machine_id(fd, id) >= 0)
return 0;
- }
fd = safe_close(fd);
r = write_string_file(run_machine_id, id);
}
if (r < 0) {
- log_error("Cannot write %s: %s", run_machine_id, strerror(-r));
- unlink(run_machine_id);
- return r;
+ (void) unlink(run_machine_id);
+ return log_error_errno(r, "Cannot write %s: %m", run_machine_id);
}
/* 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);
- unlink_noerrno(run_machine_id);
- return -errno;
+ if (mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL) < 0) {
+ (void) unlink_noerrno(run_machine_id);
+ return log_error_errno(errno, "Failed to mount %s: %m", etc_machine_id);
}
log_info("Installed transient %s file.", etc_machine_id);
/* 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;
+}
+
+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 */
+ int r;
+
+ if (isempty(root))
+ etc_machine_id = "/etc/machine-id";
+ else {
+ char *x;
+
+ x = strjoina(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
+ }
+
+ r = path_is_mount_point(etc_machine_id, false);
+ if (r < 0)
+ return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", etc_machine_id);
+ if (r == 0) {
+ log_debug("%s is is not a mount point. Nothing to do.", etc_machine_id);
+ return 0;
+ }
+
+ /* Read existing machine-id */
+ fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ 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 = is_fd_on_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);
+ if (r == 0) {
+ log_error("%s is not on a temporary file system.", etc_machine_id);
+ return -EROFS;
+ }
+
+ fd = safe_close(fd);
+
+ /* Store current mount namespace */
+ r = namespace_open(0, NULL, &initial_mntns_fd, NULL, NULL);
+ if (r < 0)
+ return log_error_errno(r, "Can't fetch current mount namespace: %m");
+
+ /* Switch to a new mount namespace, isolate ourself and unmount etc_machine_id in our new namespace */
+ if (unshare(CLONE_NEWNS) < 0)
+ return log_error_errno(errno, "Failed to enter new namespace: %m");
+
+ if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) < 0)
+ return log_error_errno(errno, "Couldn't make-rslave / mountpoint in our private namespace: %m");
+
+ if (umount(etc_machine_id) < 0)
+ 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);
+ if (r < 0)
+ return log_error_errno(r, "Cannot write %s: %m", etc_machine_id);
+
+ fd = safe_close(fd);
+
+ /* Return to initial namespace and proceed a lazy tmpfs unmount */
+ r = namespace_enter(-1, initial_mntns_fd, -1, -1);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to switch back to initial mount namespace: %m.\nWe'll keep transient %s file until next reboot.", etc_machine_id);
+
+ if (umount2(etc_machine_id, MNT_DETACH) < 0)
+ return log_warning_errno(errno, "Failed to unmount transient %s file: %m.\nWe keep that mount until next reboot.", etc_machine_id);
return 0;
}
~ianmdlvl / elogind.git / blobdiff