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authorLennart Poettering <lennart@poettering.net>2015-03-10 18:58:10 +0100
committerLennart Poettering <lennart@poettering.net>2015-03-10 19:09:38 +0100
commitc6ac7e4b98828b3b9ea5bd510cf8cc3c25dc2e58 (patch)
tree5b27f69772bcd670e2e4e8c1eb0a6626a973fb38 /src/core
parentd9dde2bb03fd2d3b71365909eaa5d0179e2fba86 (diff)
machine-id-setup: simplifications
Diffstat (limited to 'src/core')
-rw-r--r--src/core/machine-id-setup.c282
1 files changed, 140 insertions, 142 deletions
diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c
index 623dffdea..7505dcbca 100644
--- a/src/core/machine-id-setup.c
+++ b/src/core/machine-id-setup.c
@@ -40,6 +40,12 @@
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;
@@ -50,16 +56,53 @@ static int shorten_uuid(char destination[34], const char source[36]) {
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;
+}
- return -EINVAL;
+static int write_machine_id(int fd, char id[34]) {
+ assert(fd >= 0);
+ assert(id);
+
+ 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;
@@ -76,18 +119,12 @@ static int generate(char id[34], const char *root) {
/* 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) {
- r = loop_read_exact(fd, id, 33, false);
+ r = read_machine_id(fd, id);
safe_close(fd);
- if (r >= 0 && 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;
}
}
@@ -101,12 +138,10 @@ static int generate(char id[34], const char *root) {
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;
}
}
@@ -154,36 +189,96 @@ 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];
+int machine_id_setup(const char *root) {
+ const char *etc_machine_id, *run_machine_id;
+ _cleanup_close_ int fd = -1;
+ bool writable = true;
+ char id[34]; /* 32 + \n + \0 */
+ int r;
- assert(fd >= 0);
- assert(id);
+ if (isempty(root)) {
+ etc_machine_id = "/etc/machine-id";
+ run_machine_id = "/run/machine-id";
+ } else {
+ char *x;
- if (loop_read_exact(fd, id_to_validate, 33, false) >= 0 &&
- id_to_validate[32] == '\n') {
- id_to_validate[32] = 0;
+ x = strjoina(root, "/etc/machine-id");
+ etc_machine_id = path_kill_slashes(x);
- if (id128_is_valid(id_to_validate)) {
- memcpy(id, id_to_validate, 32);
- id[32] = '\n';
- id[33] = 0;
- return 0;
- }
+ x = strjoina(root, "/run/machine-id");
+ run_machine_id = path_kill_slashes(x);
}
- return -EINVAL;
-}
+ 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. */
-static int write_machine_id(int fd, char id[34]) {
- assert(fd >= 0);
- assert(id);
- lseek(fd, 0, SEEK_SET);
+ 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;
+
+ fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (fd < 0) {
+ if (old_errno == EROFS && errno == ENOENT)
+ 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_errno(errno, "Cannot open %s: %m", etc_machine_id);
+
+ return -errno;
+ }
- if (loop_write(fd, id, 33, false) == 0)
+ writable = false;
+ }
+ }
+
+ if (read_machine_id(fd, id) >= 0)
return 0;
- return -errno;
+ /* Hmm, so, the id currently stored is not useful, then let's
+ * generate one */
+
+ r = generate_machine_id(id, root);
+ if (r < 0)
+ return r;
+
+ if (writable)
+ if (write_machine_id(fd, id) >= 0)
+ return 0;
+
+ fd = safe_close(fd);
+
+ /* 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) {
+ (void) unlink(run_machine_id);
+ return log_error_errno(r, "Cannot write %s: %m", run_machine_id);
+ }
+
+ /* And now, let's mount it over */
+ 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_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id);
+
+ return 0;
}
int machine_id_commit(const char *root) {
@@ -214,7 +309,7 @@ int machine_id_commit(const char *root) {
if (fd < 0)
return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id);
- r = get_valid_machine_id(fd, 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);
@@ -264,100 +359,3 @@ int machine_id_commit(const char *root) {
return 0;
}
-
-int machine_id_setup(const char *root) {
- 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;
-
- if (isempty(root)) {
- etc_machine_id = "/etc/machine-id";
- run_machine_id = "/run/machine-id";
- } else {
- char *x;
-
- x = strjoina(root, "/etc/machine-id");
- etc_machine_id = path_kill_slashes(x);
-
- x = strjoina(root, "/run/machine-id");
- run_machine_id = path_kill_slashes(x);
- }
-
- 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. */
-
- 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;
-
- 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"
- "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;
- }
-
- writable = false;
- }
- }
-
- if (fstat(fd, &st) < 0)
- return log_error_errno(errno, "fstat() failed: %m");
-
- 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 */
-
- r = generate(id, root);
- if (r < 0)
- return r;
-
- if (S_ISREG(st.st_mode) && writable)
- if (write_machine_id(fd, id) == 0)
- return 0;
-
- fd = safe_close(fd);
-
- /* 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_errno(r, "Cannot write %s: %m", run_machine_id);
- 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_errno(errno, "Failed to mount %s: %m", etc_machine_id);
- unlink_noerrno(run_machine_id);
- return -errno;
- }
-
- 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_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id);
-
- return 0;
-}