/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** 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 <utmpx.h> #include <errno.h> #include <assert.h> #include <string.h> #include <sys/utsname.h> #include <fcntl.h> #include <unistd.h> #include <sys/poll.h> #include "macro.h" #include "path-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. */ 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(); if (!(found = getutxid(&lookup))) 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); zero(*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) { struct utmpx store; assert(id); init_timestamp(&store, 0); store.ut_type = INIT_PROCESS; store.ut_pid = pid; store.ut_session = sid; strncpy(store.ut_id, sanitize_id(id), sizeof(store.ut_id)); if (line) strncpy(store.ut_line, path_get_file_name(line), sizeof(store.ut_line)); return write_entry_both(&store); } int utmp_put_dead_process(const char *id, pid_t pid, int code, int status) { struct utmpx lookup, store, store_wtmp, *found; assert(id); setutxent(); zero(lookup); lookup.ut_type = INIT_PROCESS; /* looks for DEAD_PROCESS, LOGIN_PROCESS, USER_PROCESS, too */ strncpy(lookup.ut_id, sanitize_id(id), sizeof(lookup.ut_id)); if (!(found = getutxid(&lookup))) 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 */ if ((r = utmp_get_runlevel(&previous, NULL)) < 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, bool (*match_tty)(const char *tty)) { struct utmpx *u; char date[FORMAT_TIMESTAMP_MAX]; char *text = NULL, *hn = NULL, *un = NULL, *tty = NULL; int r; if (!(hn = gethostname_malloc()) || !(un = getlogname_malloc())) { r = -ENOMEM; goto finish; } getttyname_harder(STDIN_FILENO, &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, hn, tty ? " on " : "", strempty(tty), format_timestamp(date, sizeof(date), now(CLOCK_REALTIME)), message) < 0) { r = -ENOMEM; goto finish; } setutxent(); r = 0; while ((u = getutxent())) { int q; const char *path; char *buf = NULL; 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) { r = -ENOMEM; goto finish; } path = buf; } if (!match_tty || match_tty(path)) if ((q = write_to_terminal(path, text)) < 0) r = q; free(buf); } finish: free(hn); free(un); free(tty); free(text); return r; }