2 This file is part of systemd.
4 Copyright 2010 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
27 #include <sys/inotify.h>
28 #include <sys/socket.h>
29 #include <sys/sysmacros.h>
32 #include <linux/tiocl.h>
36 #include <sys/ioctl.h>
37 #include <sys/types.h>
41 #include "alloc-util.h"
49 #include "parse-util.h"
50 #include "path-util.h"
51 #include "process-util.h"
52 #include "socket-util.h"
53 #include "stat-util.h"
54 #include "string-util.h"
56 #include "terminal-util.h"
57 #include "time-util.h"
60 static volatile unsigned cached_columns = 0;
61 static volatile unsigned cached_lines = 0;
64 _cleanup_close_ int fd;
66 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
72 TIOCL_GETKMSGREDIRECT,
76 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
79 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
82 if (ioctl(fd, VT_ACTIVATE, vt) < 0)
88 #if 0 /// UNNEEDED by elogind
89 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
90 struct termios old_termios, new_termios;
91 char c, line[LINE_MAX];
96 if (tcgetattr(fileno(f), &old_termios) >= 0) {
97 new_termios = old_termios;
99 new_termios.c_lflag &= ~ICANON;
100 new_termios.c_cc[VMIN] = 1;
101 new_termios.c_cc[VTIME] = 0;
103 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
106 if (t != USEC_INFINITY) {
107 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
108 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
113 k = fread(&c, 1, 1, f);
115 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
121 *need_nl = c != '\n';
128 if (t != USEC_INFINITY) {
129 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
134 if (!fgets(line, sizeof(line), f))
135 return errno > 0 ? -errno : -EIO;
139 if (strlen(line) != 1)
149 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
151 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
163 if (colors_enabled())
164 fputs(ANSI_HIGHLIGHT, stdout);
172 if (colors_enabled())
173 fputs(ANSI_NORMAL, stdout);
177 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
184 puts("Bad input, please try again.");
195 if (strchr(replies, c)) {
200 puts("Read unexpected character, please try again.");
204 int ask_string(char **ret, const char *text, ...) {
212 if (colors_enabled())
213 fputs(ANSI_HIGHLIGHT, stdout);
219 if (colors_enabled())
220 fputs(ANSI_NORMAL, stdout);
225 if (!fgets(line, sizeof(line), stdin))
226 return errno > 0 ? -errno : -EIO;
228 if (!endswith(line, "\n"))
247 int reset_terminal_fd(int fd, bool switch_to_text) {
248 struct termios termios;
249 _cleanup_free_ char *utf8 = NULL;
252 /* Set terminal to some sane defaults */
256 /* We leave locked terminal attributes untouched, so that
257 * Plymouth may set whatever it wants to set, and we don't
258 * interfere with that. */
260 /* Disable exclusive mode, just in case */
261 (void) ioctl(fd, TIOCNXCL);
263 /* Switch to text mode */
265 (void) ioctl(fd, KDSETMODE, KD_TEXT);
267 /* Set default keyboard mode */
268 (void) vt_reset_keyboard(fd);
270 if (tcgetattr(fd, &termios) < 0) {
275 /* We only reset the stuff that matters to the software. How
276 * hardware is set up we don't touch assuming that somebody
277 * else will do that for us */
279 termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
280 termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
281 termios.c_oflag |= ONLCR;
282 termios.c_cflag |= CREAD;
283 termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
285 termios.c_cc[VINTR] = 03; /* ^C */
286 termios.c_cc[VQUIT] = 034; /* ^\ */
287 termios.c_cc[VERASE] = 0177;
288 termios.c_cc[VKILL] = 025; /* ^X */
289 termios.c_cc[VEOF] = 04; /* ^D */
290 termios.c_cc[VSTART] = 021; /* ^Q */
291 termios.c_cc[VSTOP] = 023; /* ^S */
292 termios.c_cc[VSUSP] = 032; /* ^Z */
293 termios.c_cc[VLNEXT] = 026; /* ^V */
294 termios.c_cc[VWERASE] = 027; /* ^W */
295 termios.c_cc[VREPRINT] = 022; /* ^R */
296 termios.c_cc[VEOL] = 0;
297 termios.c_cc[VEOL2] = 0;
299 termios.c_cc[VTIME] = 0;
300 termios.c_cc[VMIN] = 1;
302 if (tcsetattr(fd, TCSANOW, &termios) < 0)
306 /* Just in case, flush all crap out */
307 (void) tcflush(fd, TCIOFLUSH);
312 int reset_terminal(const char *name) {
313 _cleanup_close_ int fd = -1;
315 /* We open the terminal with O_NONBLOCK here, to ensure we
316 * don't block on carrier if this is a terminal with carrier
319 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
323 return reset_terminal_fd(fd, true);
327 int open_terminal(const char *name, int mode) {
332 * If a TTY is in the process of being closed opening it might
333 * cause EIO. This is horribly awful, but unlikely to be
334 * changed in the kernel. Hence we work around this problem by
335 * retrying a couple of times.
337 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
344 fd = open(name, mode, 0);
351 /* Max 1s in total */
355 usleep(50 * USEC_PER_MSEC);
368 #if 0 /// UNNEEDED by elogind
369 int acquire_terminal(
373 bool ignore_tiocstty_eperm,
376 int fd = -1, notify = -1, r = 0, wd = -1;
381 /* We use inotify to be notified when the tty is closed. We
382 * create the watch before checking if we can actually acquire
383 * it, so that we don't lose any event.
385 * Note: strictly speaking this actually watches for the
386 * device being closed, it does *not* really watch whether a
387 * tty loses its controlling process. However, unless some
388 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
389 * its tty otherwise this will not become a problem. As long
390 * as the administrator makes sure not configure any service
391 * on the same tty as an untrusted user this should not be a
392 * problem. (Which he probably should not do anyway.) */
394 if (timeout != USEC_INFINITY)
395 ts = now(CLOCK_MONOTONIC);
397 if (!fail && !force) {
398 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
404 wd = inotify_add_watch(notify, name, IN_CLOSE);
412 struct sigaction sa_old, sa_new = {
413 .sa_handler = SIG_IGN,
414 .sa_flags = SA_RESTART,
418 r = flush_fd(notify);
423 /* We pass here O_NOCTTY only so that we can check the return
424 * value TIOCSCTTY and have a reliable way to figure out if we
425 * successfully became the controlling process of the tty */
426 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
430 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
431 * if we already own the tty. */
432 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
434 /* First, try to get the tty */
435 if (ioctl(fd, TIOCSCTTY, force) < 0)
438 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
440 /* Sometimes, it makes sense to ignore TIOCSCTTY
441 * returning EPERM, i.e. when very likely we already
442 * are have this controlling terminal. */
443 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
446 if (r < 0 && (force || fail || r != -EPERM))
457 union inotify_event_buffer buffer;
458 struct inotify_event *e;
461 if (timeout != USEC_INFINITY) {
464 n = now(CLOCK_MONOTONIC);
465 if (ts + timeout < n) {
470 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
480 l = read(notify, &buffer, sizeof(buffer));
482 if (IN_SET(errno, EINTR, EAGAIN))
489 FOREACH_INOTIFY_EVENT(e, buffer, l) {
490 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
499 /* We close the tty fd here since if the old session
500 * ended our handle will be dead. It's important that
501 * we do this after sleeping, so that we don't enter
502 * an endless loop. */
518 #if 0 /// UNNEEDED by elogind
519 int release_terminal(void) {
520 static const struct sigaction sa_new = {
521 .sa_handler = SIG_IGN,
522 .sa_flags = SA_RESTART,
525 _cleanup_close_ int fd = -1;
526 struct sigaction sa_old;
529 fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
533 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
534 * by our own TIOCNOTTY */
535 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
537 if (ioctl(fd, TIOCNOTTY) < 0)
540 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
545 int terminal_vhangup_fd(int fd) {
548 if (ioctl(fd, TIOCVHANGUP) < 0)
554 int terminal_vhangup(const char *name) {
555 _cleanup_close_ int fd;
557 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
561 return terminal_vhangup_fd(fd);
564 int vt_disallocate(const char *name) {
565 _cleanup_close_ int fd = -1;
570 /* Deallocate the VT if possible. If not possible
571 * (i.e. because it is the active one), at least clear it
572 * entirely (including the scrollback buffer) */
574 e = path_startswith(name, "/dev/");
578 if (!tty_is_vc(name)) {
579 /* So this is not a VT. I guess we cannot deallocate
580 * it then. But let's at least clear the screen */
582 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
587 "\033[r" /* clear scrolling region */
588 "\033[H" /* move home */
589 "\033[2J", /* clear screen */
594 n = startswith(e, "tty");
598 r = safe_atou(n, &u);
605 /* Try to deallocate */
606 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
610 r = ioctl(fd, VT_DISALLOCATE, u);
619 /* Couldn't deallocate, so let's clear it fully with
621 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
626 "\033[r" /* clear scrolling region */
627 "\033[H" /* move home */
628 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
633 int make_console_stdio(void) {
636 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
638 fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
640 return log_error_errno(fd, "Failed to acquire terminal: %m");
642 r = reset_terminal_fd(fd, true);
644 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
648 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
654 bool tty_is_vc(const char *tty) {
657 return vtnr_from_tty(tty) >= 0;
660 bool tty_is_console(const char *tty) {
663 return streq(skip_dev_prefix(tty), "console");
666 int vtnr_from_tty(const char *tty) {
671 tty = skip_dev_prefix(tty);
673 if (!startswith(tty, "tty") )
676 if (tty[3] < '0' || tty[3] > '9')
679 r = safe_atoi(tty+3, &i);
689 #if 0 /// UNNEEDED by elogind
690 char *resolve_dev_console(char **active) {
693 /* Resolve where /dev/console is pointing to, if /sys is actually ours
694 * (i.e. not read-only-mounted which is a sign for container setups) */
696 if (path_is_read_only_fs("/sys") > 0)
699 if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
702 /* If multiple log outputs are configured the last one is what
703 * /dev/console points to */
704 tty = strrchr(*active, ' ');
710 if (streq(tty, "tty0")) {
713 /* Get the active VC (e.g. tty1) */
714 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
723 int get_kernel_consoles(char ***consoles) {
724 _cleanup_strv_free_ char **con = NULL;
725 _cleanup_free_ char *line = NULL;
731 r = read_one_line_file("/sys/class/tty/console/active", &line);
737 _cleanup_free_ char *tty = NULL;
740 r = extract_first_word(&active, &tty, NULL, 0);
746 if (streq(tty, "tty0")) {
748 r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
753 path = strappend("/dev/", tty);
757 if (access(path, F_OK) < 0) {
758 log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
763 r = strv_consume(&con, path);
768 if (strv_isempty(con)) {
769 log_debug("No devices found for system console");
771 r = strv_extend(&con, "/dev/console");
781 bool tty_is_vc_resolve(const char *tty) {
782 _cleanup_free_ char *active = NULL;
786 tty = skip_dev_prefix(tty);
788 if (streq(tty, "console")) {
789 tty = resolve_dev_console(&active);
794 return tty_is_vc(tty);
797 const char *default_term_for_tty(const char *tty) {
798 return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
802 int fd_columns(int fd) {
803 struct winsize ws = {};
805 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
814 unsigned columns(void) {
818 if (_likely_(cached_columns > 0))
819 return cached_columns;
822 e = getenv("COLUMNS");
824 (void) safe_atoi(e, &c);
827 c = fd_columns(STDOUT_FILENO);
833 return cached_columns;
836 int fd_lines(int fd) {
837 struct winsize ws = {};
839 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
848 unsigned lines(void) {
852 if (_likely_(cached_lines > 0))
858 (void) safe_atoi(e, &l);
861 l = fd_lines(STDOUT_FILENO);
870 /* intended to be used as a SIGWINCH sighandler */
871 #if 0 /// UNNEEDED by elogind
872 void columns_lines_cache_reset(int signum) {
879 static int cached_on_tty = -1;
881 if (_unlikely_(cached_on_tty < 0))
882 cached_on_tty = isatty(STDOUT_FILENO) > 0;
884 return cached_on_tty;
887 int make_stdio(int fd) {
892 r = dup2(fd, STDIN_FILENO);
893 s = dup2(fd, STDOUT_FILENO);
894 t = dup2(fd, STDERR_FILENO);
899 if (r < 0 || s < 0 || t < 0)
902 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
903 * dup2() was a NOP and the bit hence possibly set. */
904 stdio_unset_cloexec();
909 int make_null_stdio(void) {
912 null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
916 return make_stdio(null_fd);
919 int getttyname_malloc(int fd, char **ret) {
929 r = ttyname_r(fd, path, sizeof(path));
933 c = strdup(skip_dev_prefix(path));
950 int getttyname_harder(int fd, char **r) {
954 k = getttyname_malloc(fd, &s);
958 if (streq(s, "tty")) {
960 return get_ctty(0, NULL, r);
967 int get_ctty_devnr(pid_t pid, dev_t *d) {
969 _cleanup_free_ char *line = NULL;
975 p = procfs_file_alloca(pid, "stat");
976 r = read_one_line_file(p, &line);
980 p = strrchr(line, ')');
995 if (major(ttynr) == 0 && minor(ttynr) == 0)
1004 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1005 char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1006 _cleanup_free_ char *s = NULL;
1013 k = get_ctty_devnr(pid, &devnr);
1017 sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1019 k = readlink_malloc(fn, &s);
1025 /* This is an ugly hack */
1026 if (major(devnr) == 136) {
1027 if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1030 /* Probably something like the ptys which have no
1031 * symlink in /dev/char. Let's return something
1032 * vaguely useful. */
1039 if (startswith(s, "/dev/"))
1041 else if (startswith(s, "../"))
1058 #if 0 /// UNNEEDED by elogind
1059 int ptsname_malloc(int fd, char **ret) {
1072 if (ptsname_r(fd, c, l) == 0) {
1076 if (errno != ERANGE) {
1086 int ptsname_namespace(int pty, char **ret) {
1089 /* Like ptsname(), but doesn't assume that the path is
1090 * accessible in the local namespace. */
1092 r = ioctl(pty, TIOCGPTN, &no);
1099 if (asprintf(ret, "/dev/pts/%i", no) < 0)
1105 int openpt_in_namespace(pid_t pid, int flags) {
1106 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1107 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1114 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1118 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1128 pair[0] = safe_close(pair[0]);
1130 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1132 _exit(EXIT_FAILURE);
1134 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1136 _exit(EXIT_FAILURE);
1138 if (unlockpt(master) < 0)
1139 _exit(EXIT_FAILURE);
1141 if (send_one_fd(pair[1], master, 0) < 0)
1142 _exit(EXIT_FAILURE);
1144 _exit(EXIT_SUCCESS);
1147 pair[1] = safe_close(pair[1]);
1149 r = wait_for_terminate(child, &si);
1152 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1155 return receive_one_fd(pair[0], 0);
1158 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1159 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1160 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1165 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1169 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1179 pair[0] = safe_close(pair[0]);
1181 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1183 _exit(EXIT_FAILURE);
1185 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1187 _exit(EXIT_FAILURE);
1189 if (send_one_fd(pair[1], master, 0) < 0)
1190 _exit(EXIT_FAILURE);
1192 _exit(EXIT_SUCCESS);
1195 pair[1] = safe_close(pair[1]);
1197 r = wait_for_terminate(child, &si);
1200 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1203 return receive_one_fd(pair[0], 0);
1207 static bool getenv_terminal_is_dumb(void) {
1214 return streq(e, "dumb");
1217 bool terminal_is_dumb(void) {
1221 return getenv_terminal_is_dumb();
1224 bool colors_enabled(void) {
1225 static int enabled = -1;
1227 if (_unlikely_(enabled < 0)) {
1228 #if 0 /// elogind does not allow such forcing, and we are never init!
1231 val = getenv_bool("SYSTEMD_COLORS");
1234 else if (getpid_cached() == 1)
1235 /* PID1 outputs to the console without holding it open all the time */
1236 enabled = !getenv_terminal_is_dumb();
1239 enabled = !terminal_is_dumb();
1245 bool underline_enabled(void) {
1246 static int enabled = -1;
1250 /* The Linux console doesn't support underlining, turn it off, but only there. */
1252 if (!colors_enabled())
1255 enabled = !streq_ptr(getenv("TERM"), "linux");
1261 int vt_default_utf8(void) {
1262 _cleanup_free_ char *b = NULL;
1265 /* Read the default VT UTF8 setting from the kernel */
1267 r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1271 return parse_boolean(b);
1274 int vt_reset_keyboard(int fd) {
1277 /* If we can't read the default, then default to unicode. It's 2017 after all. */
1278 kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1280 if (ioctl(fd, KDSKBMODE, kb) < 0)