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 "process-util.h"
51 #include "socket-util.h"
52 #include "stat-util.h"
53 #include "string-util.h"
55 #include "terminal-util.h"
56 #include "time-util.h"
59 static volatile unsigned cached_columns = 0;
60 static volatile unsigned cached_lines = 0;
63 _cleanup_close_ int fd;
65 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
71 TIOCL_GETKMSGREDIRECT,
75 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
78 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
81 if (ioctl(fd, VT_ACTIVATE, vt) < 0)
87 #if 0 /// UNNEEDED by elogind
88 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
89 struct termios old_termios, new_termios;
90 char c, line[LINE_MAX];
95 if (tcgetattr(fileno(f), &old_termios) >= 0) {
96 new_termios = old_termios;
98 new_termios.c_lflag &= ~ICANON;
99 new_termios.c_cc[VMIN] = 1;
100 new_termios.c_cc[VTIME] = 0;
102 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
105 if (t != USEC_INFINITY) {
106 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
107 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
112 k = fread(&c, 1, 1, f);
114 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
120 *need_nl = c != '\n';
127 if (t != USEC_INFINITY) {
128 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
133 if (!fgets(line, sizeof(line), f))
134 return errno > 0 ? -errno : -EIO;
138 if (strlen(line) != 1)
148 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
150 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
162 if (colors_enabled())
163 fputs(ANSI_HIGHLIGHT, stdout);
171 if (colors_enabled())
172 fputs(ANSI_NORMAL, stdout);
176 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
183 puts("Bad input, please try again.");
194 if (strchr(replies, c)) {
199 puts("Read unexpected character, please try again.");
203 int ask_string(char **ret, const char *text, ...) {
211 if (colors_enabled())
212 fputs(ANSI_HIGHLIGHT, stdout);
218 if (colors_enabled())
219 fputs(ANSI_NORMAL, stdout);
224 if (!fgets(line, sizeof(line), stdin))
225 return errno > 0 ? -errno : -EIO;
227 if (!endswith(line, "\n"))
246 int reset_terminal_fd(int fd, bool switch_to_text) {
247 struct termios termios;
248 _cleanup_free_ char *utf8 = NULL;
251 /* Set terminal to some sane defaults */
255 /* We leave locked terminal attributes untouched, so that
256 * Plymouth may set whatever it wants to set, and we don't
257 * interfere with that. */
259 /* Disable exclusive mode, just in case */
260 (void) ioctl(fd, TIOCNXCL);
262 /* Switch to text mode */
264 (void) ioctl(fd, KDSETMODE, KD_TEXT);
266 /* Set default keyboard mode */
267 (void) vt_reset_keyboard(fd);
269 if (tcgetattr(fd, &termios) < 0) {
274 /* We only reset the stuff that matters to the software. How
275 * hardware is set up we don't touch assuming that somebody
276 * else will do that for us */
278 termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
279 termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
280 termios.c_oflag |= ONLCR;
281 termios.c_cflag |= CREAD;
282 termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
284 termios.c_cc[VINTR] = 03; /* ^C */
285 termios.c_cc[VQUIT] = 034; /* ^\ */
286 termios.c_cc[VERASE] = 0177;
287 termios.c_cc[VKILL] = 025; /* ^X */
288 termios.c_cc[VEOF] = 04; /* ^D */
289 termios.c_cc[VSTART] = 021; /* ^Q */
290 termios.c_cc[VSTOP] = 023; /* ^S */
291 termios.c_cc[VSUSP] = 032; /* ^Z */
292 termios.c_cc[VLNEXT] = 026; /* ^V */
293 termios.c_cc[VWERASE] = 027; /* ^W */
294 termios.c_cc[VREPRINT] = 022; /* ^R */
295 termios.c_cc[VEOL] = 0;
296 termios.c_cc[VEOL2] = 0;
298 termios.c_cc[VTIME] = 0;
299 termios.c_cc[VMIN] = 1;
301 if (tcsetattr(fd, TCSANOW, &termios) < 0)
305 /* Just in case, flush all crap out */
306 (void) tcflush(fd, TCIOFLUSH);
311 int reset_terminal(const char *name) {
312 _cleanup_close_ int fd = -1;
314 /* We open the terminal with O_NONBLOCK here, to ensure we
315 * don't block on carrier if this is a terminal with carrier
318 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
322 return reset_terminal_fd(fd, true);
326 int open_terminal(const char *name, int mode) {
331 * If a TTY is in the process of being closed opening it might
332 * cause EIO. This is horribly awful, but unlikely to be
333 * changed in the kernel. Hence we work around this problem by
334 * retrying a couple of times.
336 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
343 fd = open(name, mode, 0);
350 /* Max 1s in total */
354 usleep(50 * USEC_PER_MSEC);
367 #if 0 /// UNNEEDED by elogind
368 int acquire_terminal(
372 bool ignore_tiocstty_eperm,
375 int fd = -1, notify = -1, r = 0, wd = -1;
380 /* We use inotify to be notified when the tty is closed. We
381 * create the watch before checking if we can actually acquire
382 * it, so that we don't lose any event.
384 * Note: strictly speaking this actually watches for the
385 * device being closed, it does *not* really watch whether a
386 * tty loses its controlling process. However, unless some
387 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
388 * its tty otherwise this will not become a problem. As long
389 * as the administrator makes sure not configure any service
390 * on the same tty as an untrusted user this should not be a
391 * problem. (Which he probably should not do anyway.) */
393 if (timeout != USEC_INFINITY)
394 ts = now(CLOCK_MONOTONIC);
396 if (!fail && !force) {
397 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
403 wd = inotify_add_watch(notify, name, IN_CLOSE);
411 struct sigaction sa_old, sa_new = {
412 .sa_handler = SIG_IGN,
413 .sa_flags = SA_RESTART,
417 r = flush_fd(notify);
422 /* We pass here O_NOCTTY only so that we can check the return
423 * value TIOCSCTTY and have a reliable way to figure out if we
424 * successfully became the controlling process of the tty */
425 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
429 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
430 * if we already own the tty. */
431 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
433 /* First, try to get the tty */
434 if (ioctl(fd, TIOCSCTTY, force) < 0)
437 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
439 /* Sometimes, it makes sense to ignore TIOCSCTTY
440 * returning EPERM, i.e. when very likely we already
441 * are have this controlling terminal. */
442 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
445 if (r < 0 && (force || fail || r != -EPERM))
456 union inotify_event_buffer buffer;
457 struct inotify_event *e;
460 if (timeout != USEC_INFINITY) {
463 n = now(CLOCK_MONOTONIC);
464 if (ts + timeout < n) {
469 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
479 l = read(notify, &buffer, sizeof(buffer));
481 if (errno == EINTR || errno == EAGAIN)
488 FOREACH_INOTIFY_EVENT(e, buffer, l) {
489 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
498 /* We close the tty fd here since if the old session
499 * ended our handle will be dead. It's important that
500 * we do this after sleeping, so that we don't enter
501 * an endless loop. */
517 #if 0 /// UNNEEDED by elogind
518 int release_terminal(void) {
519 static const struct sigaction sa_new = {
520 .sa_handler = SIG_IGN,
521 .sa_flags = SA_RESTART,
524 _cleanup_close_ int fd = -1;
525 struct sigaction sa_old;
528 fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
532 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
533 * by our own TIOCNOTTY */
534 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
536 if (ioctl(fd, TIOCNOTTY) < 0)
539 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
544 int terminal_vhangup_fd(int fd) {
547 if (ioctl(fd, TIOCVHANGUP) < 0)
553 int terminal_vhangup(const char *name) {
554 _cleanup_close_ int fd;
556 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
560 return terminal_vhangup_fd(fd);
563 int vt_disallocate(const char *name) {
564 _cleanup_close_ int fd = -1;
569 /* Deallocate the VT if possible. If not possible
570 * (i.e. because it is the active one), at least clear it
571 * entirely (including the scrollback buffer) */
573 e = path_startswith(name, "/dev/");
577 if (!tty_is_vc(name)) {
578 /* So this is not a VT. I guess we cannot deallocate
579 * it then. But let's at least clear the screen */
581 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
586 "\033[r" /* clear scrolling region */
587 "\033[H" /* move home */
588 "\033[2J", /* clear screen */
593 n = startswith(e, "tty");
597 r = safe_atou(n, &u);
604 /* Try to deallocate */
605 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
609 r = ioctl(fd, VT_DISALLOCATE, u);
618 /* Couldn't deallocate, so let's clear it fully with
620 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
625 "\033[r" /* clear scrolling region */
626 "\033[H" /* move home */
627 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
632 int make_console_stdio(void) {
635 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
637 fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
639 return log_error_errno(fd, "Failed to acquire terminal: %m");
641 r = reset_terminal_fd(fd, true);
643 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
647 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
653 bool tty_is_vc(const char *tty) {
656 return vtnr_from_tty(tty) >= 0;
659 bool tty_is_console(const char *tty) {
662 return streq(skip_dev_prefix(tty), "console");
665 int vtnr_from_tty(const char *tty) {
670 tty = skip_dev_prefix(tty);
672 if (!startswith(tty, "tty") )
675 if (tty[3] < '0' || tty[3] > '9')
678 r = safe_atoi(tty+3, &i);
688 #if 0 /// UNNEEDED by elogind
689 char *resolve_dev_console(char **active) {
692 /* Resolve where /dev/console is pointing to, if /sys is actually ours
693 * (i.e. not read-only-mounted which is a sign for container setups) */
695 if (path_is_read_only_fs("/sys") > 0)
698 if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
701 /* If multiple log outputs are configured the last one is what
702 * /dev/console points to */
703 tty = strrchr(*active, ' ');
709 if (streq(tty, "tty0")) {
712 /* Get the active VC (e.g. tty1) */
713 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
722 int get_kernel_consoles(char ***consoles) {
723 _cleanup_strv_free_ char **con = NULL;
724 _cleanup_free_ char *line = NULL;
730 r = read_one_line_file("/sys/class/tty/console/active", &line);
736 _cleanup_free_ char *tty = NULL;
739 r = extract_first_word(&active, &tty, NULL, 0);
745 if (streq(tty, "tty0")) {
747 r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
752 path = strappend("/dev/", tty);
756 if (access(path, F_OK) < 0) {
757 log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
762 r = strv_consume(&con, path);
767 if (strv_isempty(con)) {
768 log_debug("No devices found for system console");
770 r = strv_extend(&con, "/dev/console");
780 bool tty_is_vc_resolve(const char *tty) {
781 _cleanup_free_ char *active = NULL;
785 tty = skip_dev_prefix(tty);
787 if (streq(tty, "console")) {
788 tty = resolve_dev_console(&active);
793 return tty_is_vc(tty);
796 const char *default_term_for_tty(const char *tty) {
797 return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
801 int fd_columns(int fd) {
802 struct winsize ws = {};
804 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
813 unsigned columns(void) {
817 if (_likely_(cached_columns > 0))
818 return cached_columns;
821 e = getenv("COLUMNS");
823 (void) safe_atoi(e, &c);
826 c = fd_columns(STDOUT_FILENO);
832 return cached_columns;
835 int fd_lines(int fd) {
836 struct winsize ws = {};
838 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
847 unsigned lines(void) {
851 if (_likely_(cached_lines > 0))
857 (void) safe_atoi(e, &l);
860 l = fd_lines(STDOUT_FILENO);
869 /* intended to be used as a SIGWINCH sighandler */
870 #if 0 /// UNNEEDED by elogind
871 void columns_lines_cache_reset(int signum) {
878 static int cached_on_tty = -1;
880 if (_unlikely_(cached_on_tty < 0))
881 cached_on_tty = isatty(STDOUT_FILENO) > 0;
883 return cached_on_tty;
886 int make_stdio(int fd) {
891 r = dup2(fd, STDIN_FILENO);
892 s = dup2(fd, STDOUT_FILENO);
893 t = dup2(fd, STDERR_FILENO);
898 if (r < 0 || s < 0 || t < 0)
901 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
902 * dup2() was a NOP and the bit hence possibly set. */
903 stdio_unset_cloexec();
908 int make_null_stdio(void) {
911 null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
915 return make_stdio(null_fd);
918 int getttyname_malloc(int fd, char **ret) {
928 r = ttyname_r(fd, path, sizeof(path));
932 c = strdup(skip_dev_prefix(path));
949 int getttyname_harder(int fd, char **r) {
953 k = getttyname_malloc(fd, &s);
957 if (streq(s, "tty")) {
959 return get_ctty(0, NULL, r);
966 int get_ctty_devnr(pid_t pid, dev_t *d) {
968 _cleanup_free_ char *line = NULL;
974 p = procfs_file_alloca(pid, "stat");
975 r = read_one_line_file(p, &line);
979 p = strrchr(line, ')');
994 if (major(ttynr) == 0 && minor(ttynr) == 0)
1003 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1004 char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1005 _cleanup_free_ char *s = NULL;
1012 k = get_ctty_devnr(pid, &devnr);
1016 sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1018 k = readlink_malloc(fn, &s);
1024 /* This is an ugly hack */
1025 if (major(devnr) == 136) {
1026 if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1029 /* Probably something like the ptys which have no
1030 * symlink in /dev/char. Let's return something
1031 * vaguely useful. */
1038 if (startswith(s, "/dev/"))
1040 else if (startswith(s, "../"))
1057 #if 0 /// UNNEEDED by elogind
1058 int ptsname_malloc(int fd, char **ret) {
1071 if (ptsname_r(fd, c, l) == 0) {
1075 if (errno != ERANGE) {
1085 int ptsname_namespace(int pty, char **ret) {
1088 /* Like ptsname(), but doesn't assume that the path is
1089 * accessible in the local namespace. */
1091 r = ioctl(pty, TIOCGPTN, &no);
1098 if (asprintf(ret, "/dev/pts/%i", no) < 0)
1104 int openpt_in_namespace(pid_t pid, int flags) {
1105 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1106 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1113 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1117 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1127 pair[0] = safe_close(pair[0]);
1129 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1131 _exit(EXIT_FAILURE);
1133 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1135 _exit(EXIT_FAILURE);
1137 if (unlockpt(master) < 0)
1138 _exit(EXIT_FAILURE);
1140 if (send_one_fd(pair[1], master, 0) < 0)
1141 _exit(EXIT_FAILURE);
1143 _exit(EXIT_SUCCESS);
1146 pair[1] = safe_close(pair[1]);
1148 r = wait_for_terminate(child, &si);
1151 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1154 return receive_one_fd(pair[0], 0);
1157 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1158 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1159 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1164 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1168 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1178 pair[0] = safe_close(pair[0]);
1180 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1182 _exit(EXIT_FAILURE);
1184 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1186 _exit(EXIT_FAILURE);
1188 if (send_one_fd(pair[1], master, 0) < 0)
1189 _exit(EXIT_FAILURE);
1191 _exit(EXIT_SUCCESS);
1194 pair[1] = safe_close(pair[1]);
1196 r = wait_for_terminate(child, &si);
1199 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1202 return receive_one_fd(pair[0], 0);
1206 static bool getenv_terminal_is_dumb(void) {
1213 return streq(e, "dumb");
1216 bool terminal_is_dumb(void) {
1220 return getenv_terminal_is_dumb();
1223 bool colors_enabled(void) {
1224 static int enabled = -1;
1226 if (_unlikely_(enabled < 0)) {
1227 #if 0 /// elogind does not allow such forcing, and we are never init!
1230 val = getenv_bool("SYSTEMD_COLORS");
1233 else if (getpid_cached() == 1)
1234 /* PID1 outputs to the console without holding it open all the time */
1235 enabled = !getenv_terminal_is_dumb();
1238 enabled = !terminal_is_dumb();
1244 bool underline_enabled(void) {
1245 static int enabled = -1;
1249 /* The Linux console doesn't support underlining, turn it off, but only there. */
1251 if (!colors_enabled())
1254 enabled = !streq_ptr(getenv("TERM"), "linux");
1260 int vt_default_utf8(void) {
1261 _cleanup_free_ char *b = NULL;
1264 /* Read the default VT UTF8 setting from the kernel */
1266 r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1270 return parse_boolean(b);
1273 int vt_reset_keyboard(int fd) {
1276 /* If we can't read the default, then default to unicode. It's 2017 after all. */
1277 kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1279 if (ioctl(fd, KDSKBMODE, kb) < 0)