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"
48 #include "parse-util.h"
49 #include "process-util.h"
50 #include "socket-util.h"
51 #include "stat-util.h"
52 #include "string-util.h"
54 #include "terminal-util.h"
55 #include "time-util.h"
58 static volatile unsigned cached_columns = 0;
59 static volatile unsigned cached_lines = 0;
62 _cleanup_close_ int fd;
64 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
70 TIOCL_GETKMSGREDIRECT,
74 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
77 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
80 if (ioctl(fd, VT_ACTIVATE, vt) < 0)
86 #if 0 /// UNNEEDED by elogind
87 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
88 struct termios old_termios, new_termios;
89 char c, line[LINE_MAX];
94 if (tcgetattr(fileno(f), &old_termios) >= 0) {
95 new_termios = old_termios;
97 new_termios.c_lflag &= ~ICANON;
98 new_termios.c_cc[VMIN] = 1;
99 new_termios.c_cc[VTIME] = 0;
101 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
104 if (t != USEC_INFINITY) {
105 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
106 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
111 k = fread(&c, 1, 1, f);
113 tcsetattr(fileno(f), TCSADRAIN, &old_termios);
119 *need_nl = c != '\n';
126 if (t != USEC_INFINITY) {
127 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
132 if (!fgets(line, sizeof(line), f))
133 return errno > 0 ? -errno : -EIO;
137 if (strlen(line) != 1)
147 int ask_char(char *ret, const char *replies, const char *text, ...) {
159 if (colors_enabled())
160 fputs(ANSI_HIGHLIGHT, stdout);
166 if (colors_enabled())
167 fputs(ANSI_NORMAL, stdout);
171 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
175 puts("Bad input, please try again.");
186 if (strchr(replies, c)) {
191 puts("Read unexpected character, please try again.");
195 int ask_string(char **ret, const char *text, ...) {
203 if (colors_enabled())
204 fputs(ANSI_HIGHLIGHT, stdout);
210 if (colors_enabled())
211 fputs(ANSI_NORMAL, stdout);
216 if (!fgets(line, sizeof(line), stdin))
217 return errno > 0 ? -errno : -EIO;
219 if (!endswith(line, "\n"))
238 int reset_terminal_fd(int fd, bool switch_to_text) {
239 struct termios termios;
242 /* Set terminal to some sane defaults */
246 /* We leave locked terminal attributes untouched, so that
247 * Plymouth may set whatever it wants to set, and we don't
248 * interfere with that. */
250 /* Disable exclusive mode, just in case */
251 (void) ioctl(fd, TIOCNXCL);
253 /* Switch to text mode */
255 (void) ioctl(fd, KDSETMODE, KD_TEXT);
257 /* Enable console unicode mode */
258 (void) ioctl(fd, KDSKBMODE, K_UNICODE);
260 if (tcgetattr(fd, &termios) < 0) {
265 /* We only reset the stuff that matters to the software. How
266 * hardware is set up we don't touch assuming that somebody
267 * else will do that for us */
269 termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
270 termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
271 termios.c_oflag |= ONLCR;
272 termios.c_cflag |= CREAD;
273 termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
275 termios.c_cc[VINTR] = 03; /* ^C */
276 termios.c_cc[VQUIT] = 034; /* ^\ */
277 termios.c_cc[VERASE] = 0177;
278 termios.c_cc[VKILL] = 025; /* ^X */
279 termios.c_cc[VEOF] = 04; /* ^D */
280 termios.c_cc[VSTART] = 021; /* ^Q */
281 termios.c_cc[VSTOP] = 023; /* ^S */
282 termios.c_cc[VSUSP] = 032; /* ^Z */
283 termios.c_cc[VLNEXT] = 026; /* ^V */
284 termios.c_cc[VWERASE] = 027; /* ^W */
285 termios.c_cc[VREPRINT] = 022; /* ^R */
286 termios.c_cc[VEOL] = 0;
287 termios.c_cc[VEOL2] = 0;
289 termios.c_cc[VTIME] = 0;
290 termios.c_cc[VMIN] = 1;
292 if (tcsetattr(fd, TCSANOW, &termios) < 0)
296 /* Just in case, flush all crap out */
297 (void) tcflush(fd, TCIOFLUSH);
302 int reset_terminal(const char *name) {
303 _cleanup_close_ int fd = -1;
305 /* We open the terminal with O_NONBLOCK here, to ensure we
306 * don't block on carrier if this is a terminal with carrier
309 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
313 return reset_terminal_fd(fd, true);
317 int open_terminal(const char *name, int mode) {
322 * If a TTY is in the process of being closed opening it might
323 * cause EIO. This is horribly awful, but unlikely to be
324 * changed in the kernel. Hence we work around this problem by
325 * retrying a couple of times.
327 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
334 fd = open(name, mode, 0);
341 /* Max 1s in total */
345 usleep(50 * USEC_PER_MSEC);
363 #if 0 /// UNNEEDED by elogind
364 int acquire_terminal(
368 bool ignore_tiocstty_eperm,
371 int fd = -1, notify = -1, r = 0, wd = -1;
376 /* We use inotify to be notified when the tty is closed. We
377 * create the watch before checking if we can actually acquire
378 * it, so that we don't lose any event.
380 * Note: strictly speaking this actually watches for the
381 * device being closed, it does *not* really watch whether a
382 * tty loses its controlling process. However, unless some
383 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
384 * its tty otherwise this will not become a problem. As long
385 * as the administrator makes sure not configure any service
386 * on the same tty as an untrusted user this should not be a
387 * problem. (Which he probably should not do anyway.) */
389 if (timeout != USEC_INFINITY)
390 ts = now(CLOCK_MONOTONIC);
392 if (!fail && !force) {
393 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
399 wd = inotify_add_watch(notify, name, IN_CLOSE);
407 struct sigaction sa_old, sa_new = {
408 .sa_handler = SIG_IGN,
409 .sa_flags = SA_RESTART,
413 r = flush_fd(notify);
418 /* We pass here O_NOCTTY only so that we can check the return
419 * value TIOCSCTTY and have a reliable way to figure out if we
420 * successfully became the controlling process of the tty */
421 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
425 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
426 * if we already own the tty. */
427 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
429 /* First, try to get the tty */
430 if (ioctl(fd, TIOCSCTTY, force) < 0)
433 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
435 /* Sometimes, it makes sense to ignore TIOCSCTTY
436 * returning EPERM, i.e. when very likely we already
437 * are have this controlling terminal. */
438 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
441 if (r < 0 && (force || fail || r != -EPERM))
452 union inotify_event_buffer buffer;
453 struct inotify_event *e;
456 if (timeout != USEC_INFINITY) {
459 n = now(CLOCK_MONOTONIC);
460 if (ts + timeout < n) {
465 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
475 l = read(notify, &buffer, sizeof(buffer));
477 if (errno == EINTR || errno == EAGAIN)
484 FOREACH_INOTIFY_EVENT(e, buffer, l) {
485 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
494 /* We close the tty fd here since if the old session
495 * ended our handle will be dead. It's important that
496 * we do this after sleeping, so that we don't enter
497 * an endless loop. */
513 #if 0 /// UNNEEDED by elogind
514 int release_terminal(void) {
515 static const struct sigaction sa_new = {
516 .sa_handler = SIG_IGN,
517 .sa_flags = SA_RESTART,
520 _cleanup_close_ int fd = -1;
521 struct sigaction sa_old;
524 fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
528 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
529 * by our own TIOCNOTTY */
530 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
532 if (ioctl(fd, TIOCNOTTY) < 0)
535 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
540 int terminal_vhangup_fd(int fd) {
543 if (ioctl(fd, TIOCVHANGUP) < 0)
549 int terminal_vhangup(const char *name) {
550 _cleanup_close_ int fd;
552 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
556 return terminal_vhangup_fd(fd);
559 int vt_disallocate(const char *name) {
560 _cleanup_close_ int fd = -1;
564 /* Deallocate the VT if possible. If not possible
565 * (i.e. because it is the active one), at least clear it
566 * entirely (including the scrollback buffer) */
568 if (!startswith(name, "/dev/"))
571 if (!tty_is_vc(name)) {
572 /* So this is not a VT. I guess we cannot deallocate
573 * it then. But let's at least clear the screen */
575 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
580 "\033[r" /* clear scrolling region */
581 "\033[H" /* move home */
582 "\033[2J", /* clear screen */
587 if (!startswith(name, "/dev/tty"))
590 r = safe_atou(name+8, &u);
597 /* Try to deallocate */
598 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
602 r = ioctl(fd, VT_DISALLOCATE, u);
611 /* Couldn't deallocate, so let's clear it fully with
613 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
618 "\033[r" /* clear scrolling region */
619 "\033[H" /* move home */
620 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
625 int make_console_stdio(void) {
628 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
630 fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
632 return log_error_errno(fd, "Failed to acquire terminal: %m");
634 r = reset_terminal_fd(fd, true);
636 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
640 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
646 bool tty_is_vc(const char *tty) {
649 return vtnr_from_tty(tty) >= 0;
652 bool tty_is_console(const char *tty) {
655 if (startswith(tty, "/dev/"))
658 return streq(tty, "console");
661 int vtnr_from_tty(const char *tty) {
666 if (startswith(tty, "/dev/"))
669 if (!startswith(tty, "tty") )
672 if (tty[3] < '0' || tty[3] > '9')
675 r = safe_atoi(tty+3, &i);
685 #if 0 /// UNNEEDED by elogind
686 char *resolve_dev_console(char **active) {
689 /* Resolve where /dev/console is pointing to, if /sys is actually ours
690 * (i.e. not read-only-mounted which is a sign for container setups) */
692 if (path_is_read_only_fs("/sys") > 0)
695 if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
698 /* If multiple log outputs are configured the last one is what
699 * /dev/console points to */
700 tty = strrchr(*active, ' ');
706 if (streq(tty, "tty0")) {
709 /* Get the active VC (e.g. tty1) */
710 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
719 int get_kernel_consoles(char ***consoles) {
720 _cleanup_strv_free_ char **con = NULL;
721 _cleanup_free_ char *line = NULL;
727 r = read_one_line_file("/sys/class/tty/console/active", &line);
733 _cleanup_free_ char *tty = NULL;
736 r = extract_first_word(&active, &tty, NULL, 0);
742 if (streq(tty, "tty0")) {
744 r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
749 path = strappend("/dev/", tty);
753 if (access(path, F_OK) < 0) {
754 log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
759 r = strv_consume(&con, path);
764 if (strv_isempty(con)) {
765 log_debug("No devices found for system console");
767 r = strv_extend(&con, "/dev/console");
777 bool tty_is_vc_resolve(const char *tty) {
778 _cleanup_free_ char *active = NULL;
782 if (startswith(tty, "/dev/"))
785 if (streq(tty, "console")) {
786 tty = resolve_dev_console(&active);
791 return tty_is_vc(tty);
794 const char *default_term_for_tty(const char *tty) {
795 return tty && tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
799 int fd_columns(int fd) {
800 struct winsize ws = {};
802 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
811 unsigned columns(void) {
815 if (_likely_(cached_columns > 0))
816 return cached_columns;
819 e = getenv("COLUMNS");
821 (void) safe_atoi(e, &c);
824 c = fd_columns(STDOUT_FILENO);
830 return cached_columns;
833 int fd_lines(int fd) {
834 struct winsize ws = {};
836 if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
845 unsigned lines(void) {
849 if (_likely_(cached_lines > 0))
855 (void) safe_atoi(e, &l);
858 l = fd_lines(STDOUT_FILENO);
867 /* intended to be used as a SIGWINCH sighandler */
868 #if 0 /// UNNEEDED by elogind
869 void columns_lines_cache_reset(int signum) {
876 static int cached_on_tty = -1;
878 if (_unlikely_(cached_on_tty < 0))
879 cached_on_tty = isatty(STDOUT_FILENO) > 0;
881 return cached_on_tty;
884 int make_stdio(int fd) {
889 r = dup2(fd, STDIN_FILENO);
890 s = dup2(fd, STDOUT_FILENO);
891 t = dup2(fd, STDERR_FILENO);
896 if (r < 0 || s < 0 || t < 0)
899 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
900 * dup2() was a NOP and the bit hence possibly set. */
901 stdio_unset_cloexec();
906 int make_null_stdio(void) {
909 null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
913 return make_stdio(null_fd);
916 int getttyname_malloc(int fd, char **ret) {
926 r = ttyname_r(fd, path, sizeof(path));
931 p = startswith(path, "/dev/");
932 c = strdup(p ?: 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)) {
1229 colors = getenv("SYSTEMD_COLORS");
1231 enabled = parse_boolean(colors) != 0;
1232 else if (getpid() == 1)
1233 /* PID1 outputs to the console without holding it open all the time */
1234 enabled = !getenv_terminal_is_dumb();
1236 enabled = !terminal_is_dumb();