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/>.
23 #include <linux/tiocl.h>
27 #include <sys/ioctl.h>
29 #include <sys/types.h>
34 #include "alloc-util.h"
39 #include "parse-util.h"
40 #include "path-util.h"
41 #include "process-util.h"
42 #include "socket-util.h"
43 #include "stat-util.h"
44 #include "string-util.h"
45 #include "terminal-util.h"
46 #include "time-util.h"
49 static volatile unsigned cached_columns = 0;
50 static volatile unsigned cached_lines = 0;
53 _cleanup_close_ int fd;
55 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
61 TIOCL_GETKMSGREDIRECT,
65 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
68 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
71 if (ioctl(fd, VT_ACTIVATE, vt) < 0)
77 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
78 struct termios old_termios, new_termios;
79 char c, line[LINE_MAX];
84 if (tcgetattr(fileno(f), &old_termios) >= 0) {
85 new_termios = old_termios;
87 new_termios.c_lflag &= ~ICANON;
88 new_termios.c_cc[VMIN] = 1;
89 new_termios.c_cc[VTIME] = 0;
91 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
94 if (t != USEC_INFINITY) {
95 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
96 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
101 k = fread(&c, 1, 1, f);
103 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
109 *need_nl = c != '\n';
116 if (t != USEC_INFINITY) {
117 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
122 if (!fgets(line, sizeof(line), f))
123 return errno ? -errno : -EIO;
127 if (strlen(line) != 1)
137 /// UNNEEDED by elogind
139 int ask_char(char *ret, const char *replies, const char *text, ...) {
152 fputs(ANSI_HIGHLIGHT, stdout);
159 fputs(ANSI_NORMAL, stdout);
163 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
167 puts("Bad input, please try again.");
178 if (strchr(replies, c)) {
183 puts("Read unexpected character, please try again.");
187 int ask_string(char **ret, const char *text, ...) {
196 fputs(ANSI_HIGHLIGHT, stdout);
203 fputs(ANSI_NORMAL, stdout);
208 if (!fgets(line, sizeof(line), stdin))
209 return errno ? -errno : -EIO;
211 if (!endswith(line, "\n"))
231 int reset_terminal_fd(int fd, bool switch_to_text) {
232 struct termios termios;
235 /* Set terminal to some sane defaults */
239 /* We leave locked terminal attributes untouched, so that
240 * Plymouth may set whatever it wants to set, and we don't
241 * interfere with that. */
243 /* Disable exclusive mode, just in case */
244 (void) ioctl(fd, TIOCNXCL);
246 /* Switch to text mode */
248 (void) ioctl(fd, KDSETMODE, KD_TEXT);
250 /* Enable console unicode mode */
251 (void) ioctl(fd, KDSKBMODE, K_UNICODE);
253 if (tcgetattr(fd, &termios) < 0) {
258 /* We only reset the stuff that matters to the software. How
259 * hardware is set up we don't touch assuming that somebody
260 * else will do that for us */
262 termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
263 termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
264 termios.c_oflag |= ONLCR;
265 termios.c_cflag |= CREAD;
266 termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
268 termios.c_cc[VINTR] = 03; /* ^C */
269 termios.c_cc[VQUIT] = 034; /* ^\ */
270 termios.c_cc[VERASE] = 0177;
271 termios.c_cc[VKILL] = 025; /* ^X */
272 termios.c_cc[VEOF] = 04; /* ^D */
273 termios.c_cc[VSTART] = 021; /* ^Q */
274 termios.c_cc[VSTOP] = 023; /* ^S */
275 termios.c_cc[VSUSP] = 032; /* ^Z */
276 termios.c_cc[VLNEXT] = 026; /* ^V */
277 termios.c_cc[VWERASE] = 027; /* ^W */
278 termios.c_cc[VREPRINT] = 022; /* ^R */
279 termios.c_cc[VEOL] = 0;
280 termios.c_cc[VEOL2] = 0;
282 termios.c_cc[VTIME] = 0;
283 termios.c_cc[VMIN] = 1;
285 if (tcsetattr(fd, TCSANOW, &termios) < 0)
289 /* Just in case, flush all crap out */
290 (void) tcflush(fd, TCIOFLUSH);
295 int reset_terminal(const char *name) {
296 _cleanup_close_ int fd = -1;
298 /* We open the terminal with O_NONBLOCK here, to ensure we
299 * don't block on carrier if this is a terminal with carrier
302 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
306 return reset_terminal_fd(fd, true);
309 int open_terminal(const char *name, int mode) {
314 * If a TTY is in the process of being closed opening it might
315 * cause EIO. This is horribly awful, but unlikely to be
316 * changed in the kernel. Hence we work around this problem by
317 * retrying a couple of times.
319 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
326 fd = open(name, mode, 0);
333 /* Max 1s in total */
337 usleep(50 * USEC_PER_MSEC);
355 int acquire_terminal(
359 bool ignore_tiocstty_eperm,
362 int fd = -1, notify = -1, r = 0, wd = -1;
367 /* We use inotify to be notified when the tty is closed. We
368 * create the watch before checking if we can actually acquire
369 * it, so that we don't lose any event.
371 * Note: strictly speaking this actually watches for the
372 * device being closed, it does *not* really watch whether a
373 * tty loses its controlling process. However, unless some
374 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
375 * its tty otherwise this will not become a problem. As long
376 * as the administrator makes sure not configure any service
377 * on the same tty as an untrusted user this should not be a
378 * problem. (Which he probably should not do anyway.) */
380 if (timeout != USEC_INFINITY)
381 ts = now(CLOCK_MONOTONIC);
383 if (!fail && !force) {
384 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
390 wd = inotify_add_watch(notify, name, IN_CLOSE);
398 struct sigaction sa_old, sa_new = {
399 .sa_handler = SIG_IGN,
400 .sa_flags = SA_RESTART,
404 r = flush_fd(notify);
409 /* We pass here O_NOCTTY only so that we can check the return
410 * value TIOCSCTTY and have a reliable way to figure out if we
411 * successfully became the controlling process of the tty */
412 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
416 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
417 * if we already own the tty. */
418 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
420 /* First, try to get the tty */
421 if (ioctl(fd, TIOCSCTTY, force) < 0)
424 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
426 /* Sometimes, it makes sense to ignore TIOCSCTTY
427 * returning EPERM, i.e. when very likely we already
428 * are have this controlling terminal. */
429 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
432 if (r < 0 && (force || fail || r != -EPERM))
443 union inotify_event_buffer buffer;
444 struct inotify_event *e;
447 if (timeout != USEC_INFINITY) {
450 n = now(CLOCK_MONOTONIC);
451 if (ts + timeout < n) {
456 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
466 l = read(notify, &buffer, sizeof(buffer));
468 if (errno == EINTR || errno == EAGAIN)
475 FOREACH_INOTIFY_EVENT(e, buffer, l) {
476 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
485 /* We close the tty fd here since if the old session
486 * ended our handle will be dead. It's important that
487 * we do this after sleeping, so that we don't enter
488 * an endless loop. */
503 /// UNNEEDED by elogind
505 int release_terminal(void) {
506 static const struct sigaction sa_new = {
507 .sa_handler = SIG_IGN,
508 .sa_flags = SA_RESTART,
511 _cleanup_close_ int fd = -1;
512 struct sigaction sa_old;
515 fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
519 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
520 * by our own TIOCNOTTY */
521 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
523 if (ioctl(fd, TIOCNOTTY) < 0)
526 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
532 int terminal_vhangup_fd(int fd) {
535 if (ioctl(fd, TIOCVHANGUP) < 0)
541 int terminal_vhangup(const char *name) {
542 _cleanup_close_ int fd;
544 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
548 return terminal_vhangup_fd(fd);
551 int vt_disallocate(const char *name) {
552 _cleanup_close_ int fd = -1;
556 /* Deallocate the VT if possible. If not possible
557 * (i.e. because it is the active one), at least clear it
558 * entirely (including the scrollback buffer) */
560 if (!startswith(name, "/dev/"))
563 if (!tty_is_vc(name)) {
564 /* So this is not a VT. I guess we cannot deallocate
565 * it then. But let's at least clear the screen */
567 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
572 "\033[r" /* clear scrolling region */
573 "\033[H" /* move home */
574 "\033[2J", /* clear screen */
579 if (!startswith(name, "/dev/tty"))
582 r = safe_atou(name+8, &u);
589 /* Try to deallocate */
590 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
594 r = ioctl(fd, VT_DISALLOCATE, u);
603 /* Couldn't deallocate, so let's clear it fully with
605 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
610 "\033[r" /* clear scrolling region */
611 "\033[H" /* move home */
612 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
617 /// UNNEEDED by elogind
619 int make_console_stdio(void) {
622 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
624 fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
626 return log_error_errno(fd, "Failed to acquire terminal: %m");
628 r = reset_terminal_fd(fd, true);
630 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
634 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
640 bool tty_is_vc(const char *tty) {
643 return vtnr_from_tty(tty) >= 0;
646 bool tty_is_console(const char *tty) {
649 if (startswith(tty, "/dev/"))
652 return streq(tty, "console");
655 int vtnr_from_tty(const char *tty) {
660 if (startswith(tty, "/dev/"))
663 if (!startswith(tty, "tty") )
666 if (tty[3] < '0' || tty[3] > '9')
669 r = safe_atoi(tty+3, &i);
679 char *resolve_dev_console(char **active) {
682 /* Resolve where /dev/console is pointing to, if /sys is actually ours
683 * (i.e. not read-only-mounted which is a sign for container setups) */
685 if (path_is_read_only_fs("/sys") > 0)
688 if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
691 /* If multiple log outputs are configured the last one is what
692 * /dev/console points to */
693 tty = strrchr(*active, ' ');
699 if (streq(tty, "tty0")) {
702 /* Get the active VC (e.g. tty1) */
703 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
712 bool tty_is_vc_resolve(const char *tty) {
713 _cleanup_free_ char *active = NULL;
717 if (startswith(tty, "/dev/"))
720 if (streq(tty, "console")) {
721 tty = resolve_dev_console(&active);
726 return tty_is_vc(tty);
729 /// UNNEEDED by elogind
731 const char *default_term_for_tty(const char *tty) {
734 return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
738 int fd_columns(int fd) {
739 struct winsize ws = {};
741 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
750 unsigned columns(void) {
754 if (_likely_(cached_columns > 0))
755 return cached_columns;
758 e = getenv("COLUMNS");
760 (void) safe_atoi(e, &c);
763 c = fd_columns(STDOUT_FILENO);
769 return cached_columns;
772 int fd_lines(int fd) {
773 struct winsize ws = {};
775 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
784 unsigned lines(void) {
788 if (_likely_(cached_lines > 0))
794 (void) safe_atoi(e, &l);
797 l = fd_lines(STDOUT_FILENO);
806 /* intended to be used as a SIGWINCH sighandler */
807 /// UNNEEDED by elogind
809 void columns_lines_cache_reset(int signum) {
816 static int cached_on_tty = -1;
818 if (_unlikely_(cached_on_tty < 0))
819 cached_on_tty = isatty(STDOUT_FILENO) > 0;
821 return cached_on_tty;
824 int make_stdio(int fd) {
829 r = dup2(fd, STDIN_FILENO);
830 s = dup2(fd, STDOUT_FILENO);
831 t = dup2(fd, STDERR_FILENO);
836 if (r < 0 || s < 0 || t < 0)
839 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
840 * dup2() was a NOP and the bit hence possibly set. */
841 fd_cloexec(STDIN_FILENO, false);
842 fd_cloexec(STDOUT_FILENO, false);
843 fd_cloexec(STDERR_FILENO, false);
848 int make_null_stdio(void) {
851 null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
855 return make_stdio(null_fd);
858 /// UNNEEDED by elogind
860 int getttyname_malloc(int fd, char **ret) {
870 r = ttyname_r(fd, path, sizeof(path));
875 p = startswith(path, "/dev/");
876 c = strdup(p ?: path);
893 int getttyname_harder(int fd, char **r) {
897 k = getttyname_malloc(fd, &s);
901 if (streq(s, "tty")) {
903 return get_ctty(0, NULL, r);
911 int get_ctty_devnr(pid_t pid, dev_t *d) {
913 _cleanup_free_ char *line = NULL;
919 p = procfs_file_alloca(pid, "stat");
920 r = read_one_line_file(p, &line);
924 p = strrchr(line, ')');
939 if (major(ttynr) == 0 && minor(ttynr) == 0)
948 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
949 char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
950 _cleanup_free_ char *s = NULL;
957 k = get_ctty_devnr(pid, &devnr);
961 sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
963 k = readlink_malloc(fn, &s);
969 /* This is an ugly hack */
970 if (major(devnr) == 136) {
971 if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
974 /* Probably something like the ptys which have no
975 * symlink in /dev/char. Let's return something
983 if (startswith(s, "/dev/"))
985 else if (startswith(s, "../"))
1002 /// UNNEEDED by elogind
1004 int ptsname_malloc(int fd, char **ret) {
1017 if (ptsname_r(fd, c, l) == 0) {
1021 if (errno != ERANGE) {
1031 int ptsname_namespace(int pty, char **ret) {
1034 /* Like ptsname(), but doesn't assume that the path is
1035 * accessible in the local namespace. */
1037 r = ioctl(pty, TIOCGPTN, &no);
1044 if (asprintf(ret, "/dev/pts/%i", no) < 0)
1050 int openpt_in_namespace(pid_t pid, int flags) {
1051 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1052 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1059 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1063 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1073 pair[0] = safe_close(pair[0]);
1075 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1077 _exit(EXIT_FAILURE);
1079 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1081 _exit(EXIT_FAILURE);
1083 if (unlockpt(master) < 0)
1084 _exit(EXIT_FAILURE);
1086 if (send_one_fd(pair[1], master, 0) < 0)
1087 _exit(EXIT_FAILURE);
1089 _exit(EXIT_SUCCESS);
1092 pair[1] = safe_close(pair[1]);
1094 r = wait_for_terminate(child, &si);
1097 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1100 return receive_one_fd(pair[0], 0);
1103 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1104 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1105 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1110 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1114 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1124 pair[0] = safe_close(pair[0]);
1126 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1128 _exit(EXIT_FAILURE);
1130 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1132 _exit(EXIT_FAILURE);
1134 if (send_one_fd(pair[1], master, 0) < 0)
1135 _exit(EXIT_FAILURE);
1137 _exit(EXIT_SUCCESS);
1140 pair[1] = safe_close(pair[1]);
1142 r = wait_for_terminate(child, &si);
1145 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1148 return receive_one_fd(pair[0], 0);