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 int read_one_char(FILE *f
, char *ret
, usec_t t
, bool *need_nl
) {
87 struct termios old_termios
, new_termios
;
88 char c
, line
[LINE_MAX
];
93 if (tcgetattr(fileno(f
), &old_termios
) >= 0) {
94 new_termios
= old_termios
;
96 new_termios
.c_lflag
&= ~ICANON
;
97 new_termios
.c_cc
[VMIN
] = 1;
98 new_termios
.c_cc
[VTIME
] = 0;
100 if (tcsetattr(fileno(f
), TCSADRAIN
, &new_termios
) >= 0) {
103 if (t
!= USEC_INFINITY
) {
104 if (fd_wait_for_event(fileno(f
), POLLIN
, t
) <= 0) {
105 tcsetattr(fileno(f
), TCSADRAIN
, &old_termios
);
110 k
= fread(&c
, 1, 1, f
);
112 tcsetattr(fileno(f
), TCSADRAIN
, &old_termios
);
118 *need_nl
= c
!= '\n';
125 if (t
!= USEC_INFINITY
) {
126 if (fd_wait_for_event(fileno(f
), POLLIN
, t
) <= 0)
131 if (!fgets(line
, sizeof(line
), f
))
132 return errno
> 0 ? -errno
: -EIO
;
136 if (strlen(line
) != 1)
146 int ask_char(char *ret
, const char *replies
, const char *text
, ...) {
158 if (colors_enabled())
159 fputs(ANSI_HIGHLIGHT
, stdout
);
165 if (colors_enabled())
166 fputs(ANSI_NORMAL
, stdout
);
170 r
= read_one_char(stdin
, &c
, USEC_INFINITY
, &need_nl
);
174 puts("Bad input, please try again.");
185 if (strchr(replies
, c
)) {
190 puts("Read unexpected character, please try again.");
194 int ask_string(char **ret
, const char *text
, ...) {
202 if (colors_enabled())
203 fputs(ANSI_HIGHLIGHT
, stdout
);
209 if (colors_enabled())
210 fputs(ANSI_NORMAL
, stdout
);
215 if (!fgets(line
, sizeof(line
), stdin
))
216 return errno
> 0 ? -errno
: -EIO
;
218 if (!endswith(line
, "\n"))
237 int reset_terminal_fd(int fd
, bool switch_to_text
) {
238 struct termios termios
;
241 /* Set terminal to some sane defaults */
245 /* We leave locked terminal attributes untouched, so that
246 * Plymouth may set whatever it wants to set, and we don't
247 * interfere with that. */
249 /* Disable exclusive mode, just in case */
250 (void) ioctl(fd
, TIOCNXCL
);
252 /* Switch to text mode */
254 (void) ioctl(fd
, KDSETMODE
, KD_TEXT
);
256 /* Enable console unicode mode */
257 (void) ioctl(fd
, KDSKBMODE
, K_UNICODE
);
259 if (tcgetattr(fd
, &termios
) < 0) {
264 /* We only reset the stuff that matters to the software. How
265 * hardware is set up we don't touch assuming that somebody
266 * else will do that for us */
268 termios
.c_iflag
&= ~(IGNBRK
| BRKINT
| ISTRIP
| INLCR
| IGNCR
| IUCLC
);
269 termios
.c_iflag
|= ICRNL
| IMAXBEL
| IUTF8
;
270 termios
.c_oflag
|= ONLCR
;
271 termios
.c_cflag
|= CREAD
;
272 termios
.c_lflag
= ISIG
| ICANON
| IEXTEN
| ECHO
| ECHOE
| ECHOK
| ECHOCTL
| ECHOPRT
| ECHOKE
;
274 termios
.c_cc
[VINTR
] = 03; /* ^C */
275 termios
.c_cc
[VQUIT
] = 034; /* ^\ */
276 termios
.c_cc
[VERASE
] = 0177;
277 termios
.c_cc
[VKILL
] = 025; /* ^X */
278 termios
.c_cc
[VEOF
] = 04; /* ^D */
279 termios
.c_cc
[VSTART
] = 021; /* ^Q */
280 termios
.c_cc
[VSTOP
] = 023; /* ^S */
281 termios
.c_cc
[VSUSP
] = 032; /* ^Z */
282 termios
.c_cc
[VLNEXT
] = 026; /* ^V */
283 termios
.c_cc
[VWERASE
] = 027; /* ^W */
284 termios
.c_cc
[VREPRINT
] = 022; /* ^R */
285 termios
.c_cc
[VEOL
] = 0;
286 termios
.c_cc
[VEOL2
] = 0;
288 termios
.c_cc
[VTIME
] = 0;
289 termios
.c_cc
[VMIN
] = 1;
291 if (tcsetattr(fd
, TCSANOW
, &termios
) < 0)
295 /* Just in case, flush all crap out */
296 (void) tcflush(fd
, TCIOFLUSH
);
301 int reset_terminal(const char *name
) {
302 _cleanup_close_
int fd
= -1;
304 /* We open the terminal with O_NONBLOCK here, to ensure we
305 * don't block on carrier if this is a terminal with carrier
308 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
312 return reset_terminal_fd(fd
, true);
315 int open_terminal(const char *name
, int mode
) {
320 * If a TTY is in the process of being closed opening it might
321 * cause EIO. This is horribly awful, but unlikely to be
322 * changed in the kernel. Hence we work around this problem by
323 * retrying a couple of times.
325 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
332 fd
= open(name
, mode
, 0);
339 /* Max 1s in total */
343 usleep(50 * USEC_PER_MSEC
);
361 int acquire_terminal(
365 bool ignore_tiocstty_eperm
,
368 int fd
= -1, notify
= -1, r
= 0, wd
= -1;
373 /* We use inotify to be notified when the tty is closed. We
374 * create the watch before checking if we can actually acquire
375 * it, so that we don't lose any event.
377 * Note: strictly speaking this actually watches for the
378 * device being closed, it does *not* really watch whether a
379 * tty loses its controlling process. However, unless some
380 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
381 * its tty otherwise this will not become a problem. As long
382 * as the administrator makes sure not configure any service
383 * on the same tty as an untrusted user this should not be a
384 * problem. (Which he probably should not do anyway.) */
386 if (timeout
!= USEC_INFINITY
)
387 ts
= now(CLOCK_MONOTONIC
);
389 if (!fail
&& !force
) {
390 notify
= inotify_init1(IN_CLOEXEC
| (timeout
!= USEC_INFINITY
? IN_NONBLOCK
: 0));
396 wd
= inotify_add_watch(notify
, name
, IN_CLOSE
);
404 struct sigaction sa_old
, sa_new
= {
405 .sa_handler
= SIG_IGN
,
406 .sa_flags
= SA_RESTART
,
410 r
= flush_fd(notify
);
415 /* We pass here O_NOCTTY only so that we can check the return
416 * value TIOCSCTTY and have a reliable way to figure out if we
417 * successfully became the controlling process of the tty */
418 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
422 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
423 * if we already own the tty. */
424 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
426 /* First, try to get the tty */
427 if (ioctl(fd
, TIOCSCTTY
, force
) < 0)
430 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
432 /* Sometimes, it makes sense to ignore TIOCSCTTY
433 * returning EPERM, i.e. when very likely we already
434 * are have this controlling terminal. */
435 if (r
< 0 && r
== -EPERM
&& ignore_tiocstty_eperm
)
438 if (r
< 0 && (force
|| fail
|| r
!= -EPERM
))
449 union inotify_event_buffer buffer
;
450 struct inotify_event
*e
;
453 if (timeout
!= USEC_INFINITY
) {
456 n
= now(CLOCK_MONOTONIC
);
457 if (ts
+ timeout
< n
) {
462 r
= fd_wait_for_event(fd
, POLLIN
, ts
+ timeout
- n
);
472 l
= read(notify
, &buffer
, sizeof(buffer
));
474 if (errno
== EINTR
|| errno
== EAGAIN
)
481 FOREACH_INOTIFY_EVENT(e
, buffer
, l
) {
482 if (e
->wd
!= wd
|| !(e
->mask
& IN_CLOSE
)) {
491 /* We close the tty fd here since if the old session
492 * ended our handle will be dead. It's important that
493 * we do this after sleeping, so that we don't enter
494 * an endless loop. */
509 int release_terminal(void) {
510 static const struct sigaction sa_new
= {
511 .sa_handler
= SIG_IGN
,
512 .sa_flags
= SA_RESTART
,
515 _cleanup_close_
int fd
= -1;
516 struct sigaction sa_old
;
519 fd
= open("/dev/tty", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
523 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
524 * by our own TIOCNOTTY */
525 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
527 if (ioctl(fd
, TIOCNOTTY
) < 0)
530 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
535 int terminal_vhangup_fd(int fd
) {
538 if (ioctl(fd
, TIOCVHANGUP
) < 0)
544 int terminal_vhangup(const char *name
) {
545 _cleanup_close_
int fd
;
547 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
551 return terminal_vhangup_fd(fd
);
554 int vt_disallocate(const char *name
) {
555 _cleanup_close_
int fd
= -1;
559 /* Deallocate the VT if possible. If not possible
560 * (i.e. because it is the active one), at least clear it
561 * entirely (including the scrollback buffer) */
563 if (!startswith(name
, "/dev/"))
566 if (!tty_is_vc(name
)) {
567 /* So this is not a VT. I guess we cannot deallocate
568 * it then. But let's at least clear the screen */
570 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
575 "\033[r" /* clear scrolling region */
576 "\033[H" /* move home */
577 "\033[2J", /* clear screen */
582 if (!startswith(name
, "/dev/tty"))
585 r
= safe_atou(name
+8, &u
);
592 /* Try to deallocate */
593 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
597 r
= ioctl(fd
, VT_DISALLOCATE
, u
);
606 /* Couldn't deallocate, so let's clear it fully with
608 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
613 "\033[r" /* clear scrolling region */
614 "\033[H" /* move home */
615 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
620 int make_console_stdio(void) {
623 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
625 fd
= acquire_terminal("/dev/console", false, true, true, USEC_INFINITY
);
627 return log_error_errno(fd
, "Failed to acquire terminal: %m");
629 r
= reset_terminal_fd(fd
, true);
631 log_warning_errno(r
, "Failed to reset terminal, ignoring: %m");
635 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 int get_kernel_consoles(char ***consoles
) {
713 _cleanup_strv_free_
char **con
= NULL
;
714 _cleanup_free_
char *line
= NULL
;
720 r
= read_one_line_file("/sys/class/tty/console/active", &line
);
726 _cleanup_free_
char *tty
= NULL
;
729 r
= extract_first_word(&active
, &tty
, NULL
, 0);
735 if (streq(tty
, "tty0")) {
737 r
= read_one_line_file("/sys/class/tty/tty0/active", &tty
);
742 path
= strappend("/dev/", tty
);
746 if (access(path
, F_OK
) < 0) {
747 log_debug_errno(errno
, "Console device %s is not accessible, skipping: %m", path
);
752 r
= strv_consume(&con
, path
);
757 if (strv_isempty(con
)) {
758 log_debug("No devices found for system console");
760 r
= strv_extend(&con
, "/dev/console");
770 bool tty_is_vc_resolve(const char *tty
) {
771 _cleanup_free_
char *active
= NULL
;
775 if (startswith(tty
, "/dev/"))
778 if (streq(tty
, "console")) {
779 tty
= resolve_dev_console(&active
);
784 return tty_is_vc(tty
);
787 const char *default_term_for_tty(const char *tty
) {
788 return tty
&& tty_is_vc_resolve(tty
) ? "TERM=linux" : "TERM=vt220";
791 int fd_columns(int fd
) {
792 struct winsize ws
= {};
794 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
803 unsigned columns(void) {
807 if (_likely_(cached_columns
> 0))
808 return cached_columns
;
811 e
= getenv("COLUMNS");
813 (void) safe_atoi(e
, &c
);
816 c
= fd_columns(STDOUT_FILENO
);
822 return cached_columns
;
825 int fd_lines(int fd
) {
826 struct winsize ws
= {};
828 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
837 unsigned lines(void) {
841 if (_likely_(cached_lines
> 0))
847 (void) safe_atoi(e
, &l
);
850 l
= fd_lines(STDOUT_FILENO
);
859 /* intended to be used as a SIGWINCH sighandler */
860 void columns_lines_cache_reset(int signum
) {
866 static int cached_on_tty
= -1;
868 if (_unlikely_(cached_on_tty
< 0))
869 cached_on_tty
= isatty(STDOUT_FILENO
) > 0;
871 return cached_on_tty
;
874 int make_stdio(int fd
) {
879 r
= dup2(fd
, STDIN_FILENO
);
880 s
= dup2(fd
, STDOUT_FILENO
);
881 t
= dup2(fd
, STDERR_FILENO
);
886 if (r
< 0 || s
< 0 || t
< 0)
889 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
890 * dup2() was a NOP and the bit hence possibly set. */
891 fd_cloexec(STDIN_FILENO
, false);
892 fd_cloexec(STDOUT_FILENO
, false);
893 fd_cloexec(STDERR_FILENO
, false);
898 int make_null_stdio(void) {
901 null_fd
= open("/dev/null", O_RDWR
|O_NOCTTY
);
905 return make_stdio(null_fd
);
908 int getttyname_malloc(int fd
, char **ret
) {
918 r
= ttyname_r(fd
, path
, sizeof(path
));
923 p
= startswith(path
, "/dev/");
924 c
= strdup(p
?: path
);
941 int getttyname_harder(int fd
, char **r
) {
945 k
= getttyname_malloc(fd
, &s
);
949 if (streq(s
, "tty")) {
951 return get_ctty(0, NULL
, r
);
958 int get_ctty_devnr(pid_t pid
, dev_t
*d
) {
960 _cleanup_free_
char *line
= NULL
;
966 p
= procfs_file_alloca(pid
, "stat");
967 r
= read_one_line_file(p
, &line
);
971 p
= strrchr(line
, ')');
986 if (major(ttynr
) == 0 && minor(ttynr
) == 0)
995 int get_ctty(pid_t pid
, dev_t
*_devnr
, char **r
) {
996 char fn
[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b
= NULL
;
997 _cleanup_free_
char *s
= NULL
;
1004 k
= get_ctty_devnr(pid
, &devnr
);
1008 sprintf(fn
, "/dev/char/%u:%u", major(devnr
), minor(devnr
));
1010 k
= readlink_malloc(fn
, &s
);
1016 /* This is an ugly hack */
1017 if (major(devnr
) == 136) {
1018 if (asprintf(&b
, "pts/%u", minor(devnr
)) < 0)
1021 /* Probably something like the ptys which have no
1022 * symlink in /dev/char. Let's return something
1023 * vaguely useful. */
1030 if (startswith(s
, "/dev/"))
1032 else if (startswith(s
, "../"))
1049 int ptsname_malloc(int fd
, char **ret
) {
1062 if (ptsname_r(fd
, c
, l
) == 0) {
1066 if (errno
!= ERANGE
) {
1076 int ptsname_namespace(int pty
, char **ret
) {
1079 /* Like ptsname(), but doesn't assume that the path is
1080 * accessible in the local namespace. */
1082 r
= ioctl(pty
, TIOCGPTN
, &no
);
1089 if (asprintf(ret
, "/dev/pts/%i", no
) < 0)
1095 int openpt_in_namespace(pid_t pid
, int flags
) {
1096 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1097 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1104 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1108 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1118 pair
[0] = safe_close(pair
[0]);
1120 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1122 _exit(EXIT_FAILURE
);
1124 master
= posix_openpt(flags
|O_NOCTTY
|O_CLOEXEC
);
1126 _exit(EXIT_FAILURE
);
1128 if (unlockpt(master
) < 0)
1129 _exit(EXIT_FAILURE
);
1131 if (send_one_fd(pair
[1], master
, 0) < 0)
1132 _exit(EXIT_FAILURE
);
1134 _exit(EXIT_SUCCESS
);
1137 pair
[1] = safe_close(pair
[1]);
1139 r
= wait_for_terminate(child
, &si
);
1142 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1145 return receive_one_fd(pair
[0], 0);
1148 int open_terminal_in_namespace(pid_t pid
, const char *name
, int mode
) {
1149 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1150 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1155 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1159 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1169 pair
[0] = safe_close(pair
[0]);
1171 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1173 _exit(EXIT_FAILURE
);
1175 master
= open_terminal(name
, mode
|O_NOCTTY
|O_CLOEXEC
);
1177 _exit(EXIT_FAILURE
);
1179 if (send_one_fd(pair
[1], master
, 0) < 0)
1180 _exit(EXIT_FAILURE
);
1182 _exit(EXIT_SUCCESS
);
1185 pair
[1] = safe_close(pair
[1]);
1187 r
= wait_for_terminate(child
, &si
);
1190 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1193 return receive_one_fd(pair
[0], 0);
1196 bool terminal_is_dumb(void) {
1206 return streq(e
, "dumb");
1209 bool colors_enabled(void) {
1210 static int enabled
= -1;
1212 if (_unlikely_(enabled
< 0)) {
1215 colors
= getenv("SYSTEMD_COLORS");
1217 enabled
= parse_boolean(colors
) != 0;
1219 enabled
= !terminal_is_dumb();