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 int ask_char(char *ret
, const char *replies
, const char *text
, ...) {
150 fputs(ANSI_HIGHLIGHT
, stdout
);
157 fputs(ANSI_NORMAL
, stdout
);
161 r
= read_one_char(stdin
, &c
, USEC_INFINITY
, &need_nl
);
165 puts("Bad input, please try again.");
176 if (strchr(replies
, c
)) {
181 puts("Read unexpected character, please try again.");
185 int ask_string(char **ret
, const char *text
, ...) {
194 fputs(ANSI_HIGHLIGHT
, stdout
);
201 fputs(ANSI_NORMAL
, stdout
);
206 if (!fgets(line
, sizeof(line
), stdin
))
207 return errno
? -errno
: -EIO
;
209 if (!endswith(line
, "\n"))
228 int reset_terminal_fd(int fd
, bool switch_to_text
) {
229 struct termios termios
;
232 /* Set terminal to some sane defaults */
236 /* We leave locked terminal attributes untouched, so that
237 * Plymouth may set whatever it wants to set, and we don't
238 * interfere with that. */
240 /* Disable exclusive mode, just in case */
241 (void) ioctl(fd
, TIOCNXCL
);
243 /* Switch to text mode */
245 (void) ioctl(fd
, KDSETMODE
, KD_TEXT
);
247 /* Enable console unicode mode */
248 (void) ioctl(fd
, KDSKBMODE
, K_UNICODE
);
250 if (tcgetattr(fd
, &termios
) < 0) {
255 /* We only reset the stuff that matters to the software. How
256 * hardware is set up we don't touch assuming that somebody
257 * else will do that for us */
259 termios
.c_iflag
&= ~(IGNBRK
| BRKINT
| ISTRIP
| INLCR
| IGNCR
| IUCLC
);
260 termios
.c_iflag
|= ICRNL
| IMAXBEL
| IUTF8
;
261 termios
.c_oflag
|= ONLCR
;
262 termios
.c_cflag
|= CREAD
;
263 termios
.c_lflag
= ISIG
| ICANON
| IEXTEN
| ECHO
| ECHOE
| ECHOK
| ECHOCTL
| ECHOPRT
| ECHOKE
;
265 termios
.c_cc
[VINTR
] = 03; /* ^C */
266 termios
.c_cc
[VQUIT
] = 034; /* ^\ */
267 termios
.c_cc
[VERASE
] = 0177;
268 termios
.c_cc
[VKILL
] = 025; /* ^X */
269 termios
.c_cc
[VEOF
] = 04; /* ^D */
270 termios
.c_cc
[VSTART
] = 021; /* ^Q */
271 termios
.c_cc
[VSTOP
] = 023; /* ^S */
272 termios
.c_cc
[VSUSP
] = 032; /* ^Z */
273 termios
.c_cc
[VLNEXT
] = 026; /* ^V */
274 termios
.c_cc
[VWERASE
] = 027; /* ^W */
275 termios
.c_cc
[VREPRINT
] = 022; /* ^R */
276 termios
.c_cc
[VEOL
] = 0;
277 termios
.c_cc
[VEOL2
] = 0;
279 termios
.c_cc
[VTIME
] = 0;
280 termios
.c_cc
[VMIN
] = 1;
282 if (tcsetattr(fd
, TCSANOW
, &termios
) < 0)
286 /* Just in case, flush all crap out */
287 (void) tcflush(fd
, TCIOFLUSH
);
292 int reset_terminal(const char *name
) {
293 _cleanup_close_
int fd
= -1;
295 /* We open the terminal with O_NONBLOCK here, to ensure we
296 * don't block on carrier if this is a terminal with carrier
299 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
303 return reset_terminal_fd(fd
, true);
306 int open_terminal(const char *name
, int mode
) {
311 * If a TTY is in the process of being closed opening it might
312 * cause EIO. This is horribly awful, but unlikely to be
313 * changed in the kernel. Hence we work around this problem by
314 * retrying a couple of times.
316 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
323 fd
= open(name
, mode
, 0);
330 /* Max 1s in total */
334 usleep(50 * USEC_PER_MSEC
);
352 int acquire_terminal(
356 bool ignore_tiocstty_eperm
,
359 int fd
= -1, notify
= -1, r
= 0, wd
= -1;
364 /* We use inotify to be notified when the tty is closed. We
365 * create the watch before checking if we can actually acquire
366 * it, so that we don't lose any event.
368 * Note: strictly speaking this actually watches for the
369 * device being closed, it does *not* really watch whether a
370 * tty loses its controlling process. However, unless some
371 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
372 * its tty otherwise this will not become a problem. As long
373 * as the administrator makes sure not configure any service
374 * on the same tty as an untrusted user this should not be a
375 * problem. (Which he probably should not do anyway.) */
377 if (timeout
!= USEC_INFINITY
)
378 ts
= now(CLOCK_MONOTONIC
);
380 if (!fail
&& !force
) {
381 notify
= inotify_init1(IN_CLOEXEC
| (timeout
!= USEC_INFINITY
? IN_NONBLOCK
: 0));
387 wd
= inotify_add_watch(notify
, name
, IN_CLOSE
);
395 struct sigaction sa_old
, sa_new
= {
396 .sa_handler
= SIG_IGN
,
397 .sa_flags
= SA_RESTART
,
401 r
= flush_fd(notify
);
406 /* We pass here O_NOCTTY only so that we can check the return
407 * value TIOCSCTTY and have a reliable way to figure out if we
408 * successfully became the controlling process of the tty */
409 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
413 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
414 * if we already own the tty. */
415 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
417 /* First, try to get the tty */
418 if (ioctl(fd
, TIOCSCTTY
, force
) < 0)
421 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
423 /* Sometimes it makes sense to ignore TIOCSCTTY
424 * returning EPERM, i.e. when very likely we already
425 * are have this controlling terminal. */
426 if (r
< 0 && r
== -EPERM
&& ignore_tiocstty_eperm
)
429 if (r
< 0 && (force
|| fail
|| r
!= -EPERM
))
440 union inotify_event_buffer buffer
;
441 struct inotify_event
*e
;
444 if (timeout
!= USEC_INFINITY
) {
447 n
= now(CLOCK_MONOTONIC
);
448 if (ts
+ timeout
< n
) {
453 r
= fd_wait_for_event(fd
, POLLIN
, ts
+ timeout
- n
);
463 l
= read(notify
, &buffer
, sizeof(buffer
));
465 if (errno
== EINTR
|| errno
== EAGAIN
)
472 FOREACH_INOTIFY_EVENT(e
, buffer
, l
) {
473 if (e
->wd
!= wd
|| !(e
->mask
& IN_CLOSE
)) {
482 /* We close the tty fd here since if the old session
483 * ended our handle will be dead. It's important that
484 * we do this after sleeping, so that we don't enter
485 * an endless loop. */
500 int release_terminal(void) {
501 static const struct sigaction sa_new
= {
502 .sa_handler
= SIG_IGN
,
503 .sa_flags
= SA_RESTART
,
506 _cleanup_close_
int fd
= -1;
507 struct sigaction sa_old
;
510 fd
= open("/dev/tty", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
514 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
515 * by our own TIOCNOTTY */
516 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
518 if (ioctl(fd
, TIOCNOTTY
) < 0)
521 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
526 int terminal_vhangup_fd(int fd
) {
529 if (ioctl(fd
, TIOCVHANGUP
) < 0)
535 int terminal_vhangup(const char *name
) {
536 _cleanup_close_
int fd
;
538 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
542 return terminal_vhangup_fd(fd
);
545 int vt_disallocate(const char *name
) {
546 _cleanup_close_
int fd
= -1;
550 /* Deallocate the VT if possible. If not possible
551 * (i.e. because it is the active one), at least clear it
552 * entirely (including the scrollback buffer) */
554 if (!startswith(name
, "/dev/"))
557 if (!tty_is_vc(name
)) {
558 /* So this is not a VT. I guess we cannot deallocate
559 * it then. But let's at least clear the screen */
561 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
566 "\033[r" /* clear scrolling region */
567 "\033[H" /* move home */
568 "\033[2J", /* clear screen */
573 if (!startswith(name
, "/dev/tty"))
576 r
= safe_atou(name
+8, &u
);
583 /* Try to deallocate */
584 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
588 r
= ioctl(fd
, VT_DISALLOCATE
, u
);
597 /* Couldn't deallocate, so let's clear it fully with
599 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
604 "\033[r" /* clear scrolling region */
605 "\033[H" /* move home */
606 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
611 int make_console_stdio(void) {
614 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
616 fd
= acquire_terminal("/dev/console", false, true, true, USEC_INFINITY
);
618 return log_error_errno(fd
, "Failed to acquire terminal: %m");
620 r
= reset_terminal_fd(fd
, true);
622 log_warning_errno(r
, "Failed to reset terminal, ignoring: %m");
626 return log_error_errno(r
, "Failed to duplicate terminal fd: %m");
631 bool tty_is_vc(const char *tty
) {
634 return vtnr_from_tty(tty
) >= 0;
637 bool tty_is_console(const char *tty
) {
640 if (startswith(tty
, "/dev/"))
643 return streq(tty
, "console");
646 int vtnr_from_tty(const char *tty
) {
651 if (startswith(tty
, "/dev/"))
654 if (!startswith(tty
, "tty") )
657 if (tty
[3] < '0' || tty
[3] > '9')
660 r
= safe_atoi(tty
+3, &i
);
670 char *resolve_dev_console(char **active
) {
673 /* Resolve where /dev/console is pointing to, if /sys is actually ours
674 * (i.e. not read-only-mounted which is a sign for container setups) */
676 if (path_is_read_only_fs("/sys") > 0)
679 if (read_one_line_file("/sys/class/tty/console/active", active
) < 0)
682 /* If multiple log outputs are configured the last one is what
683 * /dev/console points to */
684 tty
= strrchr(*active
, ' ');
690 if (streq(tty
, "tty0")) {
693 /* Get the active VC (e.g. tty1) */
694 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp
) >= 0) {
703 bool tty_is_vc_resolve(const char *tty
) {
704 _cleanup_free_
char *active
= NULL
;
708 if (startswith(tty
, "/dev/"))
711 if (streq(tty
, "console")) {
712 tty
= resolve_dev_console(&active
);
717 return tty_is_vc(tty
);
720 const char *default_term_for_tty(const char *tty
) {
723 return tty_is_vc_resolve(tty
) ? "TERM=linux" : "TERM=vt220";
726 int fd_columns(int fd
) {
727 struct winsize ws
= {};
729 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
738 unsigned columns(void) {
742 if (_likely_(cached_columns
> 0))
743 return cached_columns
;
746 e
= getenv("COLUMNS");
748 (void) safe_atoi(e
, &c
);
751 c
= fd_columns(STDOUT_FILENO
);
757 return cached_columns
;
760 int fd_lines(int fd
) {
761 struct winsize ws
= {};
763 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
772 unsigned lines(void) {
776 if (_likely_(cached_lines
> 0))
782 (void) safe_atoi(e
, &l
);
785 l
= fd_lines(STDOUT_FILENO
);
794 /* intended to be used as a SIGWINCH sighandler */
795 void columns_lines_cache_reset(int signum
) {
801 static int cached_on_tty
= -1;
803 if (_unlikely_(cached_on_tty
< 0))
804 cached_on_tty
= isatty(STDOUT_FILENO
) > 0;
806 return cached_on_tty
;
809 int make_stdio(int fd
) {
814 r
= dup2(fd
, STDIN_FILENO
);
815 s
= dup2(fd
, STDOUT_FILENO
);
816 t
= dup2(fd
, STDERR_FILENO
);
821 if (r
< 0 || s
< 0 || t
< 0)
824 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
825 * dup2() was a NOP and the bit hence possibly set. */
826 fd_cloexec(STDIN_FILENO
, false);
827 fd_cloexec(STDOUT_FILENO
, false);
828 fd_cloexec(STDERR_FILENO
, false);
833 int make_null_stdio(void) {
836 null_fd
= open("/dev/null", O_RDWR
|O_NOCTTY
);
840 return make_stdio(null_fd
);
843 int getttyname_malloc(int fd
, char **ret
) {
853 r
= ttyname_r(fd
, path
, sizeof(path
));
858 p
= startswith(path
, "/dev/");
859 c
= strdup(p
?: path
);
876 int getttyname_harder(int fd
, char **r
) {
880 k
= getttyname_malloc(fd
, &s
);
884 if (streq(s
, "tty")) {
886 return get_ctty(0, NULL
, r
);
893 int get_ctty_devnr(pid_t pid
, dev_t
*d
) {
895 _cleanup_free_
char *line
= NULL
;
901 p
= procfs_file_alloca(pid
, "stat");
902 r
= read_one_line_file(p
, &line
);
906 p
= strrchr(line
, ')');
921 if (major(ttynr
) == 0 && minor(ttynr
) == 0)
930 int get_ctty(pid_t pid
, dev_t
*_devnr
, char **r
) {
931 char fn
[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b
= NULL
;
932 _cleanup_free_
char *s
= NULL
;
939 k
= get_ctty_devnr(pid
, &devnr
);
943 sprintf(fn
, "/dev/char/%u:%u", major(devnr
), minor(devnr
));
945 k
= readlink_malloc(fn
, &s
);
951 /* This is an ugly hack */
952 if (major(devnr
) == 136) {
953 if (asprintf(&b
, "pts/%u", minor(devnr
)) < 0)
956 /* Probably something like the ptys which have no
957 * symlink in /dev/char. Let's return something
965 if (startswith(s
, "/dev/"))
967 else if (startswith(s
, "../"))
984 int ptsname_malloc(int fd
, char **ret
) {
997 if (ptsname_r(fd
, c
, l
) == 0) {
1001 if (errno
!= ERANGE
) {
1011 int ptsname_namespace(int pty
, char **ret
) {
1014 /* Like ptsname(), but doesn't assume that the path is
1015 * accessible in the local namespace. */
1017 r
= ioctl(pty
, TIOCGPTN
, &no
);
1024 if (asprintf(ret
, "/dev/pts/%i", no
) < 0)
1030 int openpt_in_namespace(pid_t pid
, int flags
) {
1031 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1032 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1039 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1043 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1053 pair
[0] = safe_close(pair
[0]);
1055 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1057 _exit(EXIT_FAILURE
);
1059 master
= posix_openpt(flags
|O_NOCTTY
|O_CLOEXEC
);
1061 _exit(EXIT_FAILURE
);
1063 if (unlockpt(master
) < 0)
1064 _exit(EXIT_FAILURE
);
1066 if (send_one_fd(pair
[1], master
, 0) < 0)
1067 _exit(EXIT_FAILURE
);
1069 _exit(EXIT_SUCCESS
);
1072 pair
[1] = safe_close(pair
[1]);
1074 r
= wait_for_terminate(child
, &si
);
1077 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1080 return receive_one_fd(pair
[0], 0);
1083 int open_terminal_in_namespace(pid_t pid
, const char *name
, int mode
) {
1084 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1085 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1090 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1094 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1104 pair
[0] = safe_close(pair
[0]);
1106 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1108 _exit(EXIT_FAILURE
);
1110 master
= open_terminal(name
, mode
|O_NOCTTY
|O_CLOEXEC
);
1112 _exit(EXIT_FAILURE
);
1114 if (send_one_fd(pair
[1], master
, 0) < 0)
1115 _exit(EXIT_FAILURE
);
1117 _exit(EXIT_SUCCESS
);
1120 pair
[1] = safe_close(pair
[1]);
1122 r
= wait_for_terminate(child
, &si
);
1125 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1128 return receive_one_fd(pair
[0], 0);