/*-*- Mode: C; c-basic-offset: 8 -*-*/ /*** 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 General Public License as published by the Free Software Foundation; either version 2 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 General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <utmpx.h> #include <errno.h> #include <assert.h> #include <string.h> #include <sys/utsname.h> #include "macro.h" #include "utmp-wtmp.h" int utmp_get_runlevel(int *runlevel, int *previous) { struct utmpx lookup, *found; 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. */ if ((e = getenv("RUNLEVEL")) && e[0] > 0) { *runlevel = e[0]; if (previous) { /* $PREVLEVEL seems to be an Upstart thing */ if ((e = getenv("PREVLEVEL")) && e[0] > 0) *previous = e[0]; else *previous = 0; } return 0; } if (utmpxname(_PATH_UTMPX) < 0) return -errno; setutxent(); zero(lookup); lookup.ut_type = RUN_LVL; if (!(found = getutxid(&lookup))) r = -errno; else { int a, b; a = found->ut_pid & 0xFF; b = (found->ut_pid >> 8) & 0xFF; if (a < 0 || b < 0) r = -EIO; else { *runlevel = a; if (previous) *previous = b; r = 0; } } endutxent(); return r; } static void init_entry(struct utmpx *store, usec_t t) { struct utsname uts; assert(store); zero(*store); zero(uts); 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; 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_entry_both(const struct utmpx *store) { int r, s; r = write_entry_utmp(store); s = write_entry_wtmp(store); 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; } int utmp_put_shutdown(usec_t t) { struct utmpx store; init_entry(&store, t); 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); } int utmp_put_runlevel(usec_t t, int runlevel, int previous) { struct utmpx store; int r; assert(runlevel > 0); if (previous <= 0) { /* Find the old runlevel automatically */ if ((r = utmp_get_runlevel(&previous, NULL)) < 0) { if (r != -ESRCH) return r; previous = 0; } if (previous == runlevel) return 0; } init_entry(&store, t); 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); }