src/shared/utmp-wtmp.c - systemd-stable - Rivoreo Source Code Repositories

 /*-*- 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. */

         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) {
         struct utmpx store = {
                 .ut_type = INIT_PROCESS,
                 .ut_pid = pid,
                 .ut_session = sid,
         };

         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));

         return write_entry_both(&store);
 }

 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, bool (*match_tty)(const char *tty)) {
         _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *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;
         }

         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 ?: username, hn,
                      tty ? " on " : "", strempty(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)) {
                         q = write_to_terminal(path, text);
                         if (q < 0)
                                 r = q;
                 }
         }

         return r;
 }
	/-- 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. */

	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) {
	struct utmpx store = {
	.ut_type = INIT_PROCESS,
	.ut_pid = pid,
	.ut_session = sid,
	};

	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));

	return write_entry_both(&store);
	}

	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, bool (match_tty)(const char tty)) {
	_cleanup_free_ char text = NULL, hn = NULL, un = NULL, 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;
	}

	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 ?: username, hn,
	tty ? " on " : "", strempty(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)) {
	q = write_to_terminal(path, text);
	if (q < 0)
	r = q;
	}
	}

	return r;
	}