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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/shared/utmp-wtmp.c
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/shared/utmp-wtmp.c')
-rw-r--r--src/shared/utmp-wtmp.c278
1 files changed, 278 insertions, 0 deletions
diff --git a/src/shared/utmp-wtmp.c b/src/shared/utmp-wtmp.c
new file mode 100644
index 0000000..267b350
--- /dev/null
+++ b/src/shared/utmp-wtmp.c
@@ -0,0 +1,278 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+#include <utmpx.h>
+
+#include "alloc-util.h"
+#include "errno-util.h"
+#include "hostname-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "time-util.h"
+#include "user-util.h"
+#include "utmp-wtmp.h"
+
+int utmp_get_runlevel(int *runlevel, int *previous) {
+ _unused_ _cleanup_(utxent_cleanup) bool utmpx = false;
+ struct utmpx *found, lookup = { .ut_type = RUN_LVL };
+ const char *e;
+
+ assert(runlevel);
+
+ /* If these values are set in the environment this takes
+ * precedence. Presumably, sysvinit does this to work around a
+ * race condition that would otherwise exist where we'd always
+ * go to disk and hence might read runlevel data that might be
+ * very new and not apply to the current script being executed. */
+
+ e = getenv("RUNLEVEL");
+ if (!isempty(e)) {
+ *runlevel = e[0];
+ if (previous)
+ *previous = 0;
+
+ return 0;
+ }
+
+ if (utmpxname(_PATH_UTMPX) < 0)
+ return -errno;
+
+ utmpx = utxent_start();
+
+ found = getutxid(&lookup);
+ if (!found)
+ return -errno;
+
+ *runlevel = found->ut_pid & 0xFF;
+ if (previous)
+ *previous = (found->ut_pid >> 8) & 0xFF;
+
+ return 0;
+}
+
+static void init_timestamp(struct utmpx *store, usec_t t) {
+ assert(store);
+
+ if (t <= 0)
+ t = now(CLOCK_REALTIME);
+
+ store->ut_tv.tv_sec = t / USEC_PER_SEC;
+ store->ut_tv.tv_usec = t % USEC_PER_SEC;
+}
+
+static void init_entry(struct utmpx *store, usec_t t) {
+ struct utsname uts = {};
+
+ assert(store);
+
+ init_timestamp(store, t);
+
+ if (uname(&uts) >= 0)
+ strncpy(store->ut_host, uts.release, sizeof(store->ut_host));
+
+ strncpy(store->ut_line, "~", sizeof(store->ut_line)); /* or ~~ ? */
+ strncpy(store->ut_id, "~~", sizeof(store->ut_id));
+}
+
+static int write_entry_utmp(const struct utmpx *store) {
+ _unused_ _cleanup_(utxent_cleanup) bool utmpx = false;
+
+ assert(store);
+
+ /* utmp is similar to wtmp, but there is only one entry for
+ * each entry type resp. user; i.e. basically a key/value
+ * table. */
+
+ if (utmpxname(_PATH_UTMPX) < 0)
+ return -errno;
+
+ utmpx = utxent_start();
+
+ if (pututxline(store))
+ return 0;
+ if (errno == ENOENT) {
+ /* If utmp/wtmp have been disabled, that's a good thing, hence ignore the error. */
+ log_debug_errno(errno, "Not writing utmp: %m");
+ return 0;
+ }
+ return -errno;
+}
+
+static int write_entry_wtmp(const struct utmpx *store) {
+ assert(store);
+
+ /* wtmp is a simple append-only file where each entry is
+ * simply appended to the end; i.e. basically a log. */
+
+ errno = 0;
+ updwtmpx(_PATH_WTMPX, store);
+ if (errno == ENOENT) {
+ /* If utmp/wtmp have been disabled, that's a good thing, hence ignore the error. */
+ log_debug_errno(errno, "Not writing wtmp: %m");
+ return 0;
+ }
+ if (errno == EROFS) {
+ log_warning_errno(errno, "Failed to write wtmp record, ignoring: %m");
+ return 0;
+ }
+ return -errno;
+}
+
+static int write_utmp_wtmp(const struct utmpx *store_utmp, const struct utmpx *store_wtmp) {
+ int r, s;
+
+ r = write_entry_utmp(store_utmp);
+ s = write_entry_wtmp(store_wtmp);
+ return r < 0 ? r : s;
+}
+
+static int write_entry_both(const struct utmpx *store) {
+ return write_utmp_wtmp(store, store);
+}
+
+int utmp_put_shutdown(void) {
+ struct utmpx store = {};
+
+ init_entry(&store, 0);
+
+ store.ut_type = RUN_LVL;
+ strncpy(store.ut_user, "shutdown", sizeof(store.ut_user));
+
+ return write_entry_both(&store);
+}
+
+int utmp_put_reboot(usec_t t) {
+ struct utmpx store = {};
+
+ init_entry(&store, t);
+
+ store.ut_type = BOOT_TIME;
+ strncpy(store.ut_user, "reboot", sizeof(store.ut_user));
+
+ return write_entry_both(&store);
+}
+
+static void copy_suffix(char *buf, size_t buf_size, const char *src) {
+ size_t l;
+
+ l = strlen(src);
+ if (l < buf_size)
+ strncpy(buf, src, buf_size);
+ else
+ memcpy(buf, src + l - buf_size, buf_size);
+}
+
+int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line, int ut_type, const char *user) {
+ struct utmpx store = {
+ .ut_type = INIT_PROCESS,
+ .ut_pid = pid,
+ .ut_session = sid,
+ };
+ int r;
+
+ assert(id);
+ assert(ut_type != USER_PROCESS || user);
+
+ init_timestamp(&store, 0);
+
+ /* Copy the whole string if it fits, or just the suffix without the terminating NUL. */
+ copy_suffix(store.ut_id, sizeof(store.ut_id), id);
+
+ if (line)
+ strncpy_exact(store.ut_line, line, sizeof(store.ut_line));
+
+ r = write_entry_both(&store);
+ if (r < 0)
+ return r;
+
+ if (IN_SET(ut_type, LOGIN_PROCESS, USER_PROCESS)) {
+ store.ut_type = LOGIN_PROCESS;
+ r = write_entry_both(&store);
+ if (r < 0)
+ return r;
+ }
+
+ if (ut_type == USER_PROCESS) {
+ store.ut_type = USER_PROCESS;
+ strncpy(store.ut_user, user, sizeof(store.ut_user)-1);
+ r = write_entry_both(&store);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+int utmp_put_dead_process(const char *id, pid_t pid, int code, int status) {
+ _unused_ _cleanup_(utxent_cleanup) bool utmpx = false;
+ struct utmpx lookup = {
+ .ut_type = INIT_PROCESS /* looks for DEAD_PROCESS, LOGIN_PROCESS, USER_PROCESS, too */
+ }, store, store_wtmp, *found;
+
+ assert(id);
+
+ utmpx = utxent_start();
+
+ /* Copy the whole string if it fits, or just the suffix without the terminating NUL. */
+ copy_suffix(lookup.ut_id, sizeof(lookup.ut_id), id);
+
+ found = getutxid(&lookup);
+ if (!found)
+ return 0;
+
+ if (found->ut_pid != pid)
+ return 0;
+
+ memcpy(&store, found, sizeof(store));
+ store.ut_type = DEAD_PROCESS;
+ store.ut_exit.e_termination = code;
+ store.ut_exit.e_exit = status;
+
+ zero(store.ut_user);
+ zero(store.ut_host);
+ zero(store.ut_tv);
+
+ memcpy(&store_wtmp, &store, sizeof(store_wtmp));
+ /* wtmp wants the current time */
+ init_timestamp(&store_wtmp, 0);
+
+ return write_utmp_wtmp(&store, &store_wtmp);
+}
+
+int utmp_put_runlevel(int runlevel, int previous) {
+ struct utmpx store = {};
+ int r;
+
+ assert(runlevel > 0);
+
+ if (previous <= 0) {
+ /* Find the old runlevel automatically */
+
+ r = utmp_get_runlevel(&previous, NULL);
+ if (r < 0) {
+ if (r != -ESRCH)
+ return r;
+
+ previous = 0;
+ }
+ }
+
+ if (previous == runlevel)
+ return 0;
+
+ init_entry(&store, 0);
+
+ store.ut_type = RUN_LVL;
+ store.ut_pid = (runlevel & 0xFF) | ((previous & 0xFF) << 8);
+ strncpy(store.ut_user, "runlevel", sizeof(store.ut_user));
+
+ return write_entry_both(&store);
+}