+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+#include <utmpx.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hostname-util.h"
+#include "macro.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "time-util.h"
+#include "user-util.h"
+#include "util.h"
+#include "utmp-wtmp.h"
+
+int utmp_get_runlevel(int *runlevel, int *previous) {
+ struct utmpx *found, lookup = { .ut_type = RUN_LVL };
+ int r;
+ 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 does not apply to the current script being
+ * executed. */
+
+ e = getenv("RUNLEVEL");
+ if (e && e[0] > 0) {
+ *runlevel = e[0];
+
+ if (previous) {
+ /* $PREVLEVEL seems to be an Upstart thing */
+
+ e = getenv("PREVLEVEL");
+ if (e && e[0] > 0)
+ *previous = e[0];
+ else
+ *previous = 0;
+ }
+
+ return 0;
+ }
+
+ if (utmpxname(_PATH_UTMPX) < 0)
+ return -errno;
+
+ setutxent();
+
+ found = getutxid(&lookup);
+ if (!found)
+ r = -errno;
+ else {
+ int a, b;
+
+ a = found->ut_pid & 0xFF;
+ b = (found->ut_pid >> 8) & 0xFF;
+
+ *runlevel = a;
+ if (previous)
+ *previous = b;
+
+ r = 0;
+ }
+
+ endutxent();
+
+ return r;
+}
+
+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) {
+ int r;
+
+ 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;
+
+ setutxent();
+
+ if (!pututxline(store))
+ r = -errno;
+ else
+ r = 0;
+
+ endutxent();
+
+ return r;
+}
+
+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);
+ 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);
+
+ if (r >= 0)
+ r = s;
+
+ /* If utmp/wtmp have been disabled, that's a good thing, hence
+ * ignore the errors */
+ if (r == -ENOENT)
+ r = 0;
+
+ return r;
+}
+
+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);
+}
+
+_pure_ static const char *sanitize_id(const char *id) {
+ size_t l;
+
+ assert(id);
+ l = strlen(id);
+
+ if (l <= sizeof(((struct utmpx*) NULL)->ut_id))
+ return id;
+
+ return id + l - sizeof(((struct utmpx*) NULL)->ut_id);
+}
+
+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);
+
+ init_timestamp(&store, 0);
+
+ /* ut_id needs only be nul-terminated if it is shorter than sizeof(ut_id) */
+ strncpy(store.ut_id, sanitize_id(id), sizeof(store.ut_id));
+
+ if (line)
+ strncpy(store.ut_line, basename(line), sizeof(store.ut_line));
+
+ r = write_entry_both(&store);
+ if (r < 0)
+ return r;
+
+ if (ut_type == LOGIN_PROCESS || ut_type == 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) {
+ struct utmpx lookup = {
+ .ut_type = INIT_PROCESS /* looks for DEAD_PROCESS, LOGIN_PROCESS, USER_PROCESS, too */
+ }, store, store_wtmp, *found;
+
+ assert(id);
+
+ setutxent();
+
+ /* ut_id needs only be nul-terminated if it is shorter than sizeof(ut_id) */
+ strncpy(lookup.ut_id, sanitize_id(id), sizeof(lookup.ut_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);
+}
+
+#define TIMEOUT_MSEC 50
+
+static int write_to_terminal(const char *tty, const char *message) {
+ _cleanup_close_ int fd = -1;
+ const char *p;
+ size_t left;
+ usec_t end;
+
+ assert(tty);
+ assert(message);
+
+ fd = open(tty, O_WRONLY|O_NDELAY|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0 || !isatty(fd))
+ return -errno;
+
+ p = message;
+ left = strlen(message);
+
+ end = now(CLOCK_MONOTONIC) + TIMEOUT_MSEC*USEC_PER_MSEC;
+
+ while (left > 0) {
+ ssize_t n;
+ struct pollfd pollfd = {
+ .fd = fd,
+ .events = POLLOUT,
+ };
+ usec_t t;
+ int k;
+
+ t = now(CLOCK_MONOTONIC);
+
+ if (t >= end)
+ return -ETIME;
+
+ k = poll(&pollfd, 1, (end - t) / USEC_PER_MSEC);
+ if (k < 0)
+ return -errno;
+
+ if (k == 0)
+ return -ETIME;
+
+ n = write(fd, p, left);
+ if (n < 0) {
+ if (errno == EAGAIN)
+ continue;
+
+ return -errno;
+ }
+
+ assert((size_t) n <= left);
+
+ p += n;
+ left -= n;
+ }
+
+ return 0;
+}
+
+int utmp_wall(
+ const char *message,
+ const char *username,
+ const char *origin_tty,
+ bool (*match_tty)(const char *tty, void *userdata),
+ void *userdata) {
+
+ _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *stdin_tty = NULL;
+ char date[FORMAT_TIMESTAMP_MAX];
+ struct utmpx *u;
+ int r;
+
+ hn = gethostname_malloc();
+ if (!hn)
+ return -ENOMEM;
+ if (!username) {
+ un = getlogname_malloc();
+ if (!un)
+ return -ENOMEM;
+ }
+
+ if (!origin_tty) {
+ getttyname_harder(STDIN_FILENO, &stdin_tty);
+ origin_tty = stdin_tty;
+ }
+
+ if (asprintf(&text,
+ "\a\r\n"
+ "Broadcast message from %s@%s%s%s (%s):\r\n\r\n"
+ "%s\r\n\r\n",
+ un ?: username, hn,
+ origin_tty ? " on " : "", strempty(origin_tty),
+ format_timestamp(date, sizeof(date), now(CLOCK_REALTIME)),
+ message) < 0)
+ return -ENOMEM;
+
+ setutxent();
+
+ r = 0;
+
+ while ((u = getutxent())) {
+ _cleanup_free_ char *buf = NULL;
+ const char *path;
+ int q;
+
+ if (u->ut_type != USER_PROCESS || u->ut_user[0] == 0)
+ continue;
+
+ /* this access is fine, because strlen("/dev/") << 32 (UT_LINESIZE) */
+ if (path_startswith(u->ut_line, "/dev/"))
+ path = u->ut_line;
+ else {
+ if (asprintf(&buf, "/dev/%.*s", (int) sizeof(u->ut_line), u->ut_line) < 0)
+ return -ENOMEM;
+
+ path = buf;
+ }
+
+ if (!match_tty || match_tty(path, userdata)) {
+ q = write_to_terminal(path, text);
+ if (q < 0)
+ r = q;
+ }
+ }
+
+ return r;
+}
~ianmdlvl / elogind.git / commitdiff