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;
250 /* Set terminal to some sane defaults */
254 /* We leave locked terminal attributes untouched, so that
255 * Plymouth may set whatever it wants to set, and we don't
256 * interfere with that. */
258 /* Disable exclusive mode, just in case */
259 (void) ioctl(fd, TIOCNXCL);
261 /* Switch to text mode */
263 (void) ioctl(fd, KDSETMODE, KD_TEXT);
265 /* Enable console unicode mode */
266 (void) ioctl(fd, KDSKBMODE, K_UNICODE);
268 if (tcgetattr(fd, &termios) < 0) {
273 /* We only reset the stuff that matters to the software. How
274 * hardware is set up we don't touch assuming that somebody
275 * else will do that for us */
277 termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
278 termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
279 termios.c_oflag |= ONLCR;
280 termios.c_cflag |= CREAD;
281 termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
283 termios.c_cc[VINTR] = 03; /* ^C */
284 termios.c_cc[VQUIT] = 034; /* ^\ */
285 termios.c_cc[VERASE] = 0177;
286 termios.c_cc[VKILL] = 025; /* ^X */
287 termios.c_cc[VEOF] = 04; /* ^D */
288 termios.c_cc[VSTART] = 021; /* ^Q */
289 termios.c_cc[VSTOP] = 023; /* ^S */
290 termios.c_cc[VSUSP] = 032; /* ^Z */
291 termios.c_cc[VLNEXT] = 026; /* ^V */
292 termios.c_cc[VWERASE] = 027; /* ^W */
293 termios.c_cc[VREPRINT] = 022; /* ^R */
294 termios.c_cc[VEOL] = 0;
295 termios.c_cc[VEOL2] = 0;
297 termios.c_cc[VTIME] = 0;
298 termios.c_cc[VMIN] = 1;
300 if (tcsetattr(fd, TCSANOW, &termios) < 0)
304 /* Just in case, flush all crap out */
305 (void) tcflush(fd, TCIOFLUSH);
310 int reset_terminal(const char *name) {
311 _cleanup_close_ int fd = -1;
313 /* We open the terminal with O_NONBLOCK here, to ensure we
314 * don't block on carrier if this is a terminal with carrier
317 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
321 return reset_terminal_fd(fd, true);
325 int open_terminal(const char *name, int mode) {
330 * If a TTY is in the process of being closed opening it might
331 * cause EIO. This is horribly awful, but unlikely to be
332 * changed in the kernel. Hence we work around this problem by
333 * retrying a couple of times.
335 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
342 fd = open(name, mode, 0);
349 /* Max 1s in total */
353 usleep(50 * USEC_PER_MSEC);
366 #if 0 /// UNNEEDED by elogind
367 int acquire_terminal(
371 bool ignore_tiocstty_eperm,
374 int fd = -1, notify = -1, r = 0, wd = -1;
379 /* We use inotify to be notified when the tty is closed. We
380 * create the watch before checking if we can actually acquire
381 * it, so that we don't lose any event.
383 * Note: strictly speaking this actually watches for the
384 * device being closed, it does *not* really watch whether a
385 * tty loses its controlling process. However, unless some
386 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
387 * its tty otherwise this will not become a problem. As long
388 * as the administrator makes sure not configure any service
389 * on the same tty as an untrusted user this should not be a
390 * problem. (Which he probably should not do anyway.) */
392 if (timeout != USEC_INFINITY)
393 ts = now(CLOCK_MONOTONIC);
395 if (!fail && !force) {
396 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
402 wd = inotify_add_watch(notify, name, IN_CLOSE);
410 struct sigaction sa_old, sa_new = {
411 .sa_handler = SIG_IGN,
412 .sa_flags = SA_RESTART,
416 r = flush_fd(notify);
421 /* We pass here O_NOCTTY only so that we can check the return
422 * value TIOCSCTTY and have a reliable way to figure out if we
423 * successfully became the controlling process of the tty */
424 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
428 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
429 * if we already own the tty. */
430 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
432 /* First, try to get the tty */
433 if (ioctl(fd, TIOCSCTTY, force) < 0)
436 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
438 /* Sometimes, it makes sense to ignore TIOCSCTTY
439 * returning EPERM, i.e. when very likely we already
440 * are have this controlling terminal. */
441 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
444 if (r < 0 && (force || fail || r != -EPERM))
455 union inotify_event_buffer buffer;
456 struct inotify_event *e;
459 if (timeout != USEC_INFINITY) {
462 n = now(CLOCK_MONOTONIC);
463 if (ts + timeout < n) {
468 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
478 l = read(notify, &buffer, sizeof(buffer));
480 if (errno == EINTR || errno == EAGAIN)
487 FOREACH_INOTIFY_EVENT(e, buffer, l) {
488 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
497 /* We close the tty fd here since if the old session
498 * ended our handle will be dead. It's important that
499 * we do this after sleeping, so that we don't enter
500 * an endless loop. */
516 #if 0 /// UNNEEDED by elogind
517 int release_terminal(void) {
518 static const struct sigaction sa_new = {
519 .sa_handler = SIG_IGN,
520 .sa_flags = SA_RESTART,
523 _cleanup_close_ int fd = -1;
524 struct sigaction sa_old;
527 fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
531 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
532 * by our own TIOCNOTTY */
533 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
535 if (ioctl(fd, TIOCNOTTY) < 0)
538 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
543 int terminal_vhangup_fd(int fd) {
546 if (ioctl(fd, TIOCVHANGUP) < 0)
552 int terminal_vhangup(const char *name) {
553 _cleanup_close_ int fd;
555 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
559 return terminal_vhangup_fd(fd);
562 int vt_disallocate(const char *name) {
563 _cleanup_close_ int fd = -1;
568 /* Deallocate the VT if possible. If not possible
569 * (i.e. because it is the active one), at least clear it
570 * entirely (including the scrollback buffer) */
572 e = path_startswith(name, "/dev/");
576 if (!tty_is_vc(name)) {
577 /* So this is not a VT. I guess we cannot deallocate
578 * it then. But let's at least clear the screen */
580 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
585 "\033[r" /* clear scrolling region */
586 "\033[H" /* move home */
587 "\033[2J", /* clear screen */
592 n = startswith(e, "tty");
596 r = safe_atou(n, &u);
603 /* Try to deallocate */
604 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
608 r = ioctl(fd, VT_DISALLOCATE, u);
617 /* Couldn't deallocate, so let's clear it fully with
619 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
624 "\033[r" /* clear scrolling region */
625 "\033[H" /* move home */
626 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
631 int make_console_stdio(void) {
634 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
636 fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
638 return log_error_errno(fd, "Failed to acquire terminal: %m");
640 r = reset_terminal_fd(fd, true);
642 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
646 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
652 bool tty_is_vc(const char *tty) {
655 return vtnr_from_tty(tty) >= 0;
658 bool tty_is_console(const char *tty) {
661 return streq(skip_dev_prefix(tty), "console");
664 int vtnr_from_tty(const char *tty) {
669 tty = skip_dev_prefix(tty);
671 if (!startswith(tty, "tty") )
674 if (tty[3] < '0' || tty[3] > '9')
677 r = safe_atoi(tty+3, &i);
687 #if 0 /// UNNEEDED by elogind
688 char *resolve_dev_console(char **active) {
691 /* Resolve where /dev/console is pointing to, if /sys is actually ours
692 * (i.e. not read-only-mounted which is a sign for container setups) */
694 if (path_is_read_only_fs("/sys") > 0)
697 if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
700 /* If multiple log outputs are configured the last one is what
701 * /dev/console points to */
702 tty = strrchr(*active, ' ');
708 if (streq(tty, "tty0")) {
711 /* Get the active VC (e.g. tty1) */
712 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
721 int get_kernel_consoles(char ***consoles) {
722 _cleanup_strv_free_ char **con = NULL;
723 _cleanup_free_ char *line = NULL;
729 r = read_one_line_file("/sys/class/tty/console/active", &line);
735 _cleanup_free_ char *tty = NULL;
738 r = extract_first_word(&active, &tty, NULL, 0);
744 if (streq(tty, "tty0")) {
746 r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
751 path = strappend("/dev/", tty);
755 if (access(path, F_OK) < 0) {
756 log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
761 r = strv_consume(&con, path);
766 if (strv_isempty(con)) {
767 log_debug("No devices found for system console");
769 r = strv_extend(&con, "/dev/console");
779 bool tty_is_vc_resolve(const char *tty) {
780 _cleanup_free_ char *active = NULL;
784 tty = skip_dev_prefix(tty);
786 if (streq(tty, "console")) {
787 tty = resolve_dev_console(&active);
792 return tty_is_vc(tty);
795 const char *default_term_for_tty(const char *tty) {
796 return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
800 int fd_columns(int fd) {
801 struct winsize ws = {};
803 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
812 unsigned columns(void) {
816 if (_likely_(cached_columns > 0))
817 return cached_columns;
820 e = getenv("COLUMNS");
822 (void) safe_atoi(e, &c);
825 c = fd_columns(STDOUT_FILENO);
831 return cached_columns;
834 int fd_lines(int fd) {
835 struct winsize ws = {};
837 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
846 unsigned lines(void) {
850 if (_likely_(cached_lines > 0))
856 (void) safe_atoi(e, &l);
859 l = fd_lines(STDOUT_FILENO);
868 /* intended to be used as a SIGWINCH sighandler */
869 #if 0 /// UNNEEDED by elogind
870 void columns_lines_cache_reset(int signum) {
877 static int cached_on_tty = -1;
879 if (_unlikely_(cached_on_tty < 0))
880 cached_on_tty = isatty(STDOUT_FILENO) > 0;
882 return cached_on_tty;
885 int make_stdio(int fd) {
890 r = dup2(fd, STDIN_FILENO);
891 s = dup2(fd, STDOUT_FILENO);
892 t = dup2(fd, STDERR_FILENO);
897 if (r < 0 || s < 0 || t < 0)
900 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
901 * dup2() was a NOP and the bit hence possibly set. */
902 stdio_unset_cloexec();
907 int make_null_stdio(void) {
910 null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
914 return make_stdio(null_fd);
917 int getttyname_malloc(int fd, char **ret) {
927 r = ttyname_r(fd, path, sizeof(path));
931 c = strdup(skip_dev_prefix(path));
948 int getttyname_harder(int fd, char **r) {
952 k = getttyname_malloc(fd, &s);
956 if (streq(s, "tty")) {
958 return get_ctty(0, NULL, r);
965 int get_ctty_devnr(pid_t pid, dev_t *d) {
967 _cleanup_free_ char *line = NULL;
973 p = procfs_file_alloca(pid, "stat");
974 r = read_one_line_file(p, &line);
978 p = strrchr(line, ')');
993 if (major(ttynr) == 0 && minor(ttynr) == 0)
1002 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1003 char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1004 _cleanup_free_ char *s = NULL;
1011 k = get_ctty_devnr(pid, &devnr);
1015 sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1017 k = readlink_malloc(fn, &s);
1023 /* This is an ugly hack */
1024 if (major(devnr) == 136) {
1025 if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1028 /* Probably something like the ptys which have no
1029 * symlink in /dev/char. Let's return something
1030 * vaguely useful. */
1037 if (startswith(s, "/dev/"))
1039 else if (startswith(s, "../"))
1056 #if 0 /// UNNEEDED by elogind
1057 int ptsname_malloc(int fd, char **ret) {
1070 if (ptsname_r(fd, c, l) == 0) {
1074 if (errno != ERANGE) {
1084 int ptsname_namespace(int pty, char **ret) {
1087 /* Like ptsname(), but doesn't assume that the path is
1088 * accessible in the local namespace. */
1090 r = ioctl(pty, TIOCGPTN, &no);
1097 if (asprintf(ret, "/dev/pts/%i", no) < 0)
1103 int openpt_in_namespace(pid_t pid, int flags) {
1104 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1105 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1112 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1116 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1126 pair[0] = safe_close(pair[0]);
1128 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1130 _exit(EXIT_FAILURE);
1132 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1134 _exit(EXIT_FAILURE);
1136 if (unlockpt(master) < 0)
1137 _exit(EXIT_FAILURE);
1139 if (send_one_fd(pair[1], master, 0) < 0)
1140 _exit(EXIT_FAILURE);
1142 _exit(EXIT_SUCCESS);
1145 pair[1] = safe_close(pair[1]);
1147 r = wait_for_terminate(child, &si);
1150 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1153 return receive_one_fd(pair[0], 0);
1156 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1157 _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1158 _cleanup_close_pair_ int pair[2] = { -1, -1 };
1163 r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1167 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1177 pair[0] = safe_close(pair[0]);
1179 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1181 _exit(EXIT_FAILURE);
1183 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1185 _exit(EXIT_FAILURE);
1187 if (send_one_fd(pair[1], master, 0) < 0)
1188 _exit(EXIT_FAILURE);
1190 _exit(EXIT_SUCCESS);
1193 pair[1] = safe_close(pair[1]);
1195 r = wait_for_terminate(child, &si);
1198 if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1201 return receive_one_fd(pair[0], 0);
1205 static bool getenv_terminal_is_dumb(void) {
1212 return streq(e, "dumb");
1215 bool terminal_is_dumb(void) {
1219 return getenv_terminal_is_dumb();
1222 bool colors_enabled(void) {
1223 static int enabled = -1;
1225 if (_unlikely_(enabled < 0)) {
1226 #if 0 /// elogind does not allow such forcing, and we are never init!
1229 val = getenv_bool("SYSTEMD_COLORS");
1232 else if (getpid_cached() == 1)
1233 /* PID1 outputs to the console without holding it open all the time */
1234 enabled = !getenv_terminal_is_dumb();
1237 enabled = !terminal_is_dumb();