432 lines
11 KiB
C
432 lines
11 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <utmpx.h>
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#include <errno.h>
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#include <assert.h>
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#include <string.h>
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#include <sys/utsname.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/poll.h>
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#include "macro.h"
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#include "path-util.h"
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#include "utmp-wtmp.h"
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int utmp_get_runlevel(int *runlevel, int *previous) {
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struct utmpx lookup, *found;
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int r;
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const char *e;
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assert(runlevel);
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/* If these values are set in the environment this takes
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* precedence. Presumably, sysvinit does this to work around a
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* race condition that would otherwise exist where we'd always
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* go to disk and hence might read runlevel data that might be
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* very new and does not apply to the current script being
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* executed. */
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if ((e = getenv("RUNLEVEL")) && e[0] > 0) {
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*runlevel = e[0];
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if (previous) {
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/* $PREVLEVEL seems to be an Upstart thing */
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if ((e = getenv("PREVLEVEL")) && e[0] > 0)
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*previous = e[0];
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else
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*previous = 0;
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}
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return 0;
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}
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if (utmpxname(_PATH_UTMPX) < 0)
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return -errno;
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setutxent();
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zero(lookup);
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lookup.ut_type = RUN_LVL;
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if (!(found = getutxid(&lookup)))
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r = -errno;
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else {
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int a, b;
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a = found->ut_pid & 0xFF;
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b = (found->ut_pid >> 8) & 0xFF;
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if (a < 0 || b < 0)
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r = -EIO;
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else {
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*runlevel = a;
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if (previous)
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*previous = b;
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r = 0;
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}
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}
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endutxent();
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return r;
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}
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static void init_timestamp(struct utmpx *store, usec_t t) {
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assert(store);
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zero(*store);
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if (t <= 0)
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t = now(CLOCK_REALTIME);
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store->ut_tv.tv_sec = t / USEC_PER_SEC;
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store->ut_tv.tv_usec = t % USEC_PER_SEC;
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}
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static void init_entry(struct utmpx *store, usec_t t) {
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struct utsname uts;
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assert(store);
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init_timestamp(store, t);
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zero(uts);
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if (uname(&uts) >= 0)
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strncpy(store->ut_host, uts.release, sizeof(store->ut_host));
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strncpy(store->ut_line, "~", sizeof(store->ut_line)); /* or ~~ ? */
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strncpy(store->ut_id, "~~", sizeof(store->ut_id));
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}
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static int write_entry_utmp(const struct utmpx *store) {
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int r;
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assert(store);
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/* utmp is similar to wtmp, but there is only one entry for
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* each entry type resp. user; i.e. basically a key/value
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* table. */
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if (utmpxname(_PATH_UTMPX) < 0)
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return -errno;
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setutxent();
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if (!pututxline(store))
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r = -errno;
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else
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r = 0;
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endutxent();
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return r;
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}
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static int write_entry_wtmp(const struct utmpx *store) {
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assert(store);
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/* wtmp is a simple append-only file where each entry is
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simply appended to * the end; i.e. basically a log. */
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errno = 0;
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updwtmpx(_PATH_WTMPX, store);
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return -errno;
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}
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static int write_utmp_wtmp(const struct utmpx *store_utmp, const struct utmpx *store_wtmp) {
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int r, s;
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r = write_entry_utmp(store_utmp);
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s = write_entry_wtmp(store_wtmp);
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if (r >= 0)
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r = s;
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/* If utmp/wtmp have been disabled, that's a good thing, hence
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* ignore the errors */
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if (r == -ENOENT)
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r = 0;
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return r;
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}
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static int write_entry_both(const struct utmpx *store) {
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return write_utmp_wtmp(store, store);
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}
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int utmp_put_shutdown(void) {
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struct utmpx store;
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init_entry(&store, 0);
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store.ut_type = RUN_LVL;
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strncpy(store.ut_user, "shutdown", sizeof(store.ut_user));
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return write_entry_both(&store);
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}
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int utmp_put_reboot(usec_t t) {
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struct utmpx store;
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init_entry(&store, t);
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store.ut_type = BOOT_TIME;
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strncpy(store.ut_user, "reboot", sizeof(store.ut_user));
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return write_entry_both(&store);
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}
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static const char *sanitize_id(const char *id) {
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size_t l;
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assert(id);
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l = strlen(id);
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if (l <= sizeof(((struct utmpx*) NULL)->ut_id))
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return id;
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return id + l - sizeof(((struct utmpx*) NULL)->ut_id);
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}
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int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line) {
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struct utmpx store;
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assert(id);
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init_timestamp(&store, 0);
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store.ut_type = INIT_PROCESS;
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store.ut_pid = pid;
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store.ut_session = sid;
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strncpy(store.ut_id, sanitize_id(id), sizeof(store.ut_id));
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if (line)
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strncpy(store.ut_line, path_get_file_name(line), sizeof(store.ut_line));
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return write_entry_both(&store);
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}
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int utmp_put_dead_process(const char *id, pid_t pid, int code, int status) {
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struct utmpx lookup, store, store_wtmp, *found;
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assert(id);
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setutxent();
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zero(lookup);
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lookup.ut_type = INIT_PROCESS; /* looks for DEAD_PROCESS, LOGIN_PROCESS, USER_PROCESS, too */
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strncpy(lookup.ut_id, sanitize_id(id), sizeof(lookup.ut_id));
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if (!(found = getutxid(&lookup)))
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return 0;
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if (found->ut_pid != pid)
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return 0;
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memcpy(&store, found, sizeof(store));
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store.ut_type = DEAD_PROCESS;
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store.ut_exit.e_termination = code;
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store.ut_exit.e_exit = status;
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zero(store.ut_user);
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zero(store.ut_host);
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zero(store.ut_tv);
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memcpy(&store_wtmp, &store, sizeof(store_wtmp));
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/* wtmp wants the current time */
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init_timestamp(&store_wtmp, 0);
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return write_utmp_wtmp(&store, &store_wtmp);
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}
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int utmp_put_runlevel(int runlevel, int previous) {
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struct utmpx store;
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int r;
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assert(runlevel > 0);
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if (previous <= 0) {
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/* Find the old runlevel automatically */
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if ((r = utmp_get_runlevel(&previous, NULL)) < 0) {
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if (r != -ESRCH)
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return r;
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previous = 0;
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}
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}
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if (previous == runlevel)
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return 0;
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init_entry(&store, 0);
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store.ut_type = RUN_LVL;
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store.ut_pid = (runlevel & 0xFF) | ((previous & 0xFF) << 8);
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strncpy(store.ut_user, "runlevel", sizeof(store.ut_user));
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return write_entry_both(&store);
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}
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#define TIMEOUT_MSEC 50
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static int write_to_terminal(const char *tty, const char *message) {
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int fd, r;
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const char *p;
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size_t left;
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usec_t end;
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assert(tty);
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assert(message);
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if ((fd = open(tty, O_WRONLY|O_NDELAY|O_NOCTTY|O_CLOEXEC)) < 0)
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return -errno;
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if (!isatty(fd)) {
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r = -errno;
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goto finish;
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}
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p = message;
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left = strlen(message);
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end = now(CLOCK_MONOTONIC) + TIMEOUT_MSEC*USEC_PER_MSEC;
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while (left > 0) {
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ssize_t n;
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struct pollfd pollfd;
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usec_t t;
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int k;
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t = now(CLOCK_MONOTONIC);
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if (t >= end) {
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r = -ETIME;
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goto finish;
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}
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zero(pollfd);
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pollfd.fd = fd;
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pollfd.events = POLLOUT;
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if ((k = poll(&pollfd, 1, (end - t) / USEC_PER_MSEC)) < 0)
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return -errno;
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if (k <= 0) {
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r = -ETIME;
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goto finish;
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}
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if ((n = write(fd, p, left)) < 0) {
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if (errno == EAGAIN)
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continue;
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r = -errno;
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goto finish;
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}
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assert((size_t) n <= left);
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p += n;
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left -= n;
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}
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r = 0;
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finish:
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close_nointr_nofail(fd);
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return r;
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}
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int utmp_wall(const char *message, bool (*match_tty)(const char *tty)) {
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struct utmpx *u;
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char date[FORMAT_TIMESTAMP_MAX];
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char *text = NULL, *hn = NULL, *un = NULL, *tty = NULL;
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int r;
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if (!(hn = gethostname_malloc()) ||
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!(un = getlogname_malloc())) {
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r = -ENOMEM;
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goto finish;
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}
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getttyname_harder(STDIN_FILENO, &tty);
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if (asprintf(&text,
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"\a\r\n"
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"Broadcast message from %s@%s%s%s (%s):\r\n\r\n"
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"%s\r\n\r\n",
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un, hn,
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tty ? " on " : "", strempty(tty),
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format_timestamp(date, sizeof(date), now(CLOCK_REALTIME)),
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message) < 0) {
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r = -ENOMEM;
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goto finish;
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}
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setutxent();
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r = 0;
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while ((u = getutxent())) {
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int q;
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const char *path;
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char *buf = NULL;
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if (u->ut_type != USER_PROCESS || u->ut_user[0] == 0)
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continue;
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if (path_startswith(u->ut_line, "/dev/"))
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path = u->ut_line;
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else {
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if (asprintf(&buf, "/dev/%s", u->ut_line) < 0) {
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r = -ENOMEM;
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goto finish;
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}
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path = buf;
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}
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if (!match_tty || match_tty(path))
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if ((q = write_to_terminal(path, text)) < 0)
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r = q;
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free(buf);
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}
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finish:
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free(hn);
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free(un);
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free(tty);
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free(text);
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return r;
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}
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