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"
53 #include "terminal-util.h"
54 #include "time-util.h"
57 static volatile unsigned cached_columns
= 0;
58 static volatile unsigned cached_lines
= 0;
61 _cleanup_close_
int fd
;
63 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
69 TIOCL_GETKMSGREDIRECT
,
73 if (ioctl(fd
, TIOCLINUX
, tiocl
) < 0)
76 vt
= tiocl
[0] <= 0 ? 1 : tiocl
[0];
79 if (ioctl(fd
, VT_ACTIVATE
, vt
) < 0)
85 int read_one_char(FILE *f
, char *ret
, usec_t t
, bool *need_nl
) {
86 struct termios old_termios
, new_termios
;
87 char c
, line
[LINE_MAX
];
92 if (tcgetattr(fileno(f
), &old_termios
) >= 0) {
93 new_termios
= old_termios
;
95 new_termios
.c_lflag
&= ~ICANON
;
96 new_termios
.c_cc
[VMIN
] = 1;
97 new_termios
.c_cc
[VTIME
] = 0;
99 if (tcsetattr(fileno(f
), TCSADRAIN
, &new_termios
) >= 0) {
102 if (t
!= USEC_INFINITY
) {
103 if (fd_wait_for_event(fileno(f
), POLLIN
, t
) <= 0) {
104 tcsetattr(fileno(f
), TCSADRAIN
, &old_termios
);
109 k
= fread(&c
, 1, 1, f
);
111 tcsetattr(fileno(f
), TCSADRAIN
, &old_termios
);
117 *need_nl
= c
!= '\n';
124 if (t
!= USEC_INFINITY
) {
125 if (fd_wait_for_event(fileno(f
), POLLIN
, t
) <= 0)
130 if (!fgets(line
, sizeof(line
), f
))
131 return errno
> 0 ? -errno
: -EIO
;
135 if (strlen(line
) != 1)
145 int ask_char(char *ret
, const char *replies
, const char *text
, ...) {
158 fputs(ANSI_HIGHLIGHT
, stdout
);
165 fputs(ANSI_NORMAL
, stdout
);
169 r
= read_one_char(stdin
, &c
, USEC_INFINITY
, &need_nl
);
173 puts("Bad input, please try again.");
184 if (strchr(replies
, c
)) {
189 puts("Read unexpected character, please try again.");
193 int ask_string(char **ret
, const char *text
, ...) {
202 fputs(ANSI_HIGHLIGHT
, stdout
);
209 fputs(ANSI_NORMAL
, stdout
);
214 if (!fgets(line
, sizeof(line
), stdin
))
215 return errno
> 0 ? -errno
: -EIO
;
217 if (!endswith(line
, "\n"))
236 int reset_terminal_fd(int fd
, bool switch_to_text
) {
237 struct termios termios
;
240 /* Set terminal to some sane defaults */
244 /* We leave locked terminal attributes untouched, so that
245 * Plymouth may set whatever it wants to set, and we don't
246 * interfere with that. */
248 /* Disable exclusive mode, just in case */
249 (void) ioctl(fd
, TIOCNXCL
);
251 /* Switch to text mode */
253 (void) ioctl(fd
, KDSETMODE
, KD_TEXT
);
255 /* Enable console unicode mode */
256 (void) ioctl(fd
, KDSKBMODE
, K_UNICODE
);
258 if (tcgetattr(fd
, &termios
) < 0) {
263 /* We only reset the stuff that matters to the software. How
264 * hardware is set up we don't touch assuming that somebody
265 * else will do that for us */
267 termios
.c_iflag
&= ~(IGNBRK
| BRKINT
| ISTRIP
| INLCR
| IGNCR
| IUCLC
);
268 termios
.c_iflag
|= ICRNL
| IMAXBEL
| IUTF8
;
269 termios
.c_oflag
|= ONLCR
;
270 termios
.c_cflag
|= CREAD
;
271 termios
.c_lflag
= ISIG
| ICANON
| IEXTEN
| ECHO
| ECHOE
| ECHOK
| ECHOCTL
| ECHOPRT
| ECHOKE
;
273 termios
.c_cc
[VINTR
] = 03; /* ^C */
274 termios
.c_cc
[VQUIT
] = 034; /* ^\ */
275 termios
.c_cc
[VERASE
] = 0177;
276 termios
.c_cc
[VKILL
] = 025; /* ^X */
277 termios
.c_cc
[VEOF
] = 04; /* ^D */
278 termios
.c_cc
[VSTART
] = 021; /* ^Q */
279 termios
.c_cc
[VSTOP
] = 023; /* ^S */
280 termios
.c_cc
[VSUSP
] = 032; /* ^Z */
281 termios
.c_cc
[VLNEXT
] = 026; /* ^V */
282 termios
.c_cc
[VWERASE
] = 027; /* ^W */
283 termios
.c_cc
[VREPRINT
] = 022; /* ^R */
284 termios
.c_cc
[VEOL
] = 0;
285 termios
.c_cc
[VEOL2
] = 0;
287 termios
.c_cc
[VTIME
] = 0;
288 termios
.c_cc
[VMIN
] = 1;
290 if (tcsetattr(fd
, TCSANOW
, &termios
) < 0)
294 /* Just in case, flush all crap out */
295 (void) tcflush(fd
, TCIOFLUSH
);
300 int reset_terminal(const char *name
) {
301 _cleanup_close_
int fd
= -1;
303 /* We open the terminal with O_NONBLOCK here, to ensure we
304 * don't block on carrier if this is a terminal with carrier
307 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
311 return reset_terminal_fd(fd
, true);
314 int open_terminal(const char *name
, int mode
) {
319 * If a TTY is in the process of being closed opening it might
320 * cause EIO. This is horribly awful, but unlikely to be
321 * changed in the kernel. Hence we work around this problem by
322 * retrying a couple of times.
324 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
331 fd
= open(name
, mode
, 0);
338 /* Max 1s in total */
342 usleep(50 * USEC_PER_MSEC
);
360 int acquire_terminal(
364 bool ignore_tiocstty_eperm
,
367 int fd
= -1, notify
= -1, r
= 0, wd
= -1;
372 /* We use inotify to be notified when the tty is closed. We
373 * create the watch before checking if we can actually acquire
374 * it, so that we don't lose any event.
376 * Note: strictly speaking this actually watches for the
377 * device being closed, it does *not* really watch whether a
378 * tty loses its controlling process. However, unless some
379 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
380 * its tty otherwise this will not become a problem. As long
381 * as the administrator makes sure not configure any service
382 * on the same tty as an untrusted user this should not be a
383 * problem. (Which he probably should not do anyway.) */
385 if (timeout
!= USEC_INFINITY
)
386 ts
= now(CLOCK_MONOTONIC
);
388 if (!fail
&& !force
) {
389 notify
= inotify_init1(IN_CLOEXEC
| (timeout
!= USEC_INFINITY
? IN_NONBLOCK
: 0));
395 wd
= inotify_add_watch(notify
, name
, IN_CLOSE
);
403 struct sigaction sa_old
, sa_new
= {
404 .sa_handler
= SIG_IGN
,
405 .sa_flags
= SA_RESTART
,
409 r
= flush_fd(notify
);
414 /* We pass here O_NOCTTY only so that we can check the return
415 * value TIOCSCTTY and have a reliable way to figure out if we
416 * successfully became the controlling process of the tty */
417 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
421 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
422 * if we already own the tty. */
423 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
425 /* First, try to get the tty */
426 if (ioctl(fd
, TIOCSCTTY
, force
) < 0)
429 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
431 /* Sometimes, it makes sense to ignore TIOCSCTTY
432 * returning EPERM, i.e. when very likely we already
433 * are have this controlling terminal. */
434 if (r
< 0 && r
== -EPERM
&& ignore_tiocstty_eperm
)
437 if (r
< 0 && (force
|| fail
|| r
!= -EPERM
))
448 union inotify_event_buffer buffer
;
449 struct inotify_event
*e
;
452 if (timeout
!= USEC_INFINITY
) {
455 n
= now(CLOCK_MONOTONIC
);
456 if (ts
+ timeout
< n
) {
461 r
= fd_wait_for_event(fd
, POLLIN
, ts
+ timeout
- n
);
471 l
= read(notify
, &buffer
, sizeof(buffer
));
473 if (errno
== EINTR
|| errno
== EAGAIN
)
480 FOREACH_INOTIFY_EVENT(e
, buffer
, l
) {
481 if (e
->wd
!= wd
|| !(e
->mask
& IN_CLOSE
)) {
490 /* We close the tty fd here since if the old session
491 * ended our handle will be dead. It's important that
492 * we do this after sleeping, so that we don't enter
493 * an endless loop. */
508 int release_terminal(void) {
509 static const struct sigaction sa_new
= {
510 .sa_handler
= SIG_IGN
,
511 .sa_flags
= SA_RESTART
,
514 _cleanup_close_
int fd
= -1;
515 struct sigaction sa_old
;
518 fd
= open("/dev/tty", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
522 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
523 * by our own TIOCNOTTY */
524 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
526 if (ioctl(fd
, TIOCNOTTY
) < 0)
529 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
534 int terminal_vhangup_fd(int fd
) {
537 if (ioctl(fd
, TIOCVHANGUP
) < 0)
543 int terminal_vhangup(const char *name
) {
544 _cleanup_close_
int fd
;
546 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
550 return terminal_vhangup_fd(fd
);
553 int vt_disallocate(const char *name
) {
554 _cleanup_close_
int fd
= -1;
558 /* Deallocate the VT if possible. If not possible
559 * (i.e. because it is the active one), at least clear it
560 * entirely (including the scrollback buffer) */
562 if (!startswith(name
, "/dev/"))
565 if (!tty_is_vc(name
)) {
566 /* So this is not a VT. I guess we cannot deallocate
567 * it then. But let's at least clear the screen */
569 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
574 "\033[r" /* clear scrolling region */
575 "\033[H" /* move home */
576 "\033[2J", /* clear screen */
581 if (!startswith(name
, "/dev/tty"))
584 r
= safe_atou(name
+8, &u
);
591 /* Try to deallocate */
592 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
596 r
= ioctl(fd
, VT_DISALLOCATE
, u
);
605 /* Couldn't deallocate, so let's clear it fully with
607 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
612 "\033[r" /* clear scrolling region */
613 "\033[H" /* move home */
614 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
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");
639 bool tty_is_vc(const char *tty
) {
642 return vtnr_from_tty(tty
) >= 0;
645 bool tty_is_console(const char *tty
) {
648 if (startswith(tty
, "/dev/"))
651 return streq(tty
, "console");
654 int vtnr_from_tty(const char *tty
) {
659 if (startswith(tty
, "/dev/"))
662 if (!startswith(tty
, "tty") )
665 if (tty
[3] < '0' || tty
[3] > '9')
668 r
= safe_atoi(tty
+3, &i
);
678 char *resolve_dev_console(char **active
) {
681 /* Resolve where /dev/console is pointing to, if /sys is actually ours
682 * (i.e. not read-only-mounted which is a sign for container setups) */
684 if (path_is_read_only_fs("/sys") > 0)
687 if (read_one_line_file("/sys/class/tty/console/active", active
) < 0)
690 /* If multiple log outputs are configured the last one is what
691 * /dev/console points to */
692 tty
= strrchr(*active
, ' ');
698 if (streq(tty
, "tty0")) {
701 /* Get the active VC (e.g. tty1) */
702 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp
) >= 0) {
711 bool tty_is_vc_resolve(const char *tty
) {
712 _cleanup_free_
char *active
= NULL
;
716 if (startswith(tty
, "/dev/"))
719 if (streq(tty
, "console")) {
720 tty
= resolve_dev_console(&active
);
725 return tty_is_vc(tty
);
728 const char *default_term_for_tty(const char *tty
) {
729 return tty
&& tty_is_vc_resolve(tty
) ? "TERM=linux" : "TERM=vt220";
732 int fd_columns(int fd
) {
733 struct winsize ws
= {};
735 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
744 unsigned columns(void) {
748 if (_likely_(cached_columns
> 0))
749 return cached_columns
;
752 e
= getenv("COLUMNS");
754 (void) safe_atoi(e
, &c
);
757 c
= fd_columns(STDOUT_FILENO
);
763 return cached_columns
;
766 int fd_lines(int fd
) {
767 struct winsize ws
= {};
769 if (ioctl(fd
, TIOCGWINSZ
, &ws
) < 0)
778 unsigned lines(void) {
782 if (_likely_(cached_lines
> 0))
788 (void) safe_atoi(e
, &l
);
791 l
= fd_lines(STDOUT_FILENO
);
800 /* intended to be used as a SIGWINCH sighandler */
801 void columns_lines_cache_reset(int signum
) {
807 static int cached_on_tty
= -1;
809 if (_unlikely_(cached_on_tty
< 0))
810 cached_on_tty
= isatty(STDOUT_FILENO
) > 0;
812 return cached_on_tty
;
815 int make_stdio(int fd
) {
820 r
= dup2(fd
, STDIN_FILENO
);
821 s
= dup2(fd
, STDOUT_FILENO
);
822 t
= dup2(fd
, STDERR_FILENO
);
827 if (r
< 0 || s
< 0 || t
< 0)
830 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
831 * dup2() was a NOP and the bit hence possibly set. */
832 fd_cloexec(STDIN_FILENO
, false);
833 fd_cloexec(STDOUT_FILENO
, false);
834 fd_cloexec(STDERR_FILENO
, false);
839 int make_null_stdio(void) {
842 null_fd
= open("/dev/null", O_RDWR
|O_NOCTTY
);
846 return make_stdio(null_fd
);
849 int getttyname_malloc(int fd
, char **ret
) {
859 r
= ttyname_r(fd
, path
, sizeof(path
));
864 p
= startswith(path
, "/dev/");
865 c
= strdup(p
?: path
);
882 int getttyname_harder(int fd
, char **r
) {
886 k
= getttyname_malloc(fd
, &s
);
890 if (streq(s
, "tty")) {
892 return get_ctty(0, NULL
, r
);
899 int get_ctty_devnr(pid_t pid
, dev_t
*d
) {
901 _cleanup_free_
char *line
= NULL
;
907 p
= procfs_file_alloca(pid
, "stat");
908 r
= read_one_line_file(p
, &line
);
912 p
= strrchr(line
, ')');
927 if (major(ttynr
) == 0 && minor(ttynr
) == 0)
936 int get_ctty(pid_t pid
, dev_t
*_devnr
, char **r
) {
937 char fn
[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b
= NULL
;
938 _cleanup_free_
char *s
= NULL
;
945 k
= get_ctty_devnr(pid
, &devnr
);
949 sprintf(fn
, "/dev/char/%u:%u", major(devnr
), minor(devnr
));
951 k
= readlink_malloc(fn
, &s
);
957 /* This is an ugly hack */
958 if (major(devnr
) == 136) {
959 if (asprintf(&b
, "pts/%u", minor(devnr
)) < 0)
962 /* Probably something like the ptys which have no
963 * symlink in /dev/char. Let's return something
971 if (startswith(s
, "/dev/"))
973 else if (startswith(s
, "../"))
990 int ptsname_malloc(int fd
, char **ret
) {
1003 if (ptsname_r(fd
, c
, l
) == 0) {
1007 if (errno
!= ERANGE
) {
1017 int ptsname_namespace(int pty
, char **ret
) {
1020 /* Like ptsname(), but doesn't assume that the path is
1021 * accessible in the local namespace. */
1023 r
= ioctl(pty
, TIOCGPTN
, &no
);
1030 if (asprintf(ret
, "/dev/pts/%i", no
) < 0)
1036 int openpt_in_namespace(pid_t pid
, int flags
) {
1037 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1038 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1045 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1049 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1059 pair
[0] = safe_close(pair
[0]);
1061 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1063 _exit(EXIT_FAILURE
);
1065 master
= posix_openpt(flags
|O_NOCTTY
|O_CLOEXEC
);
1067 _exit(EXIT_FAILURE
);
1069 if (unlockpt(master
) < 0)
1070 _exit(EXIT_FAILURE
);
1072 if (send_one_fd(pair
[1], master
, 0) < 0)
1073 _exit(EXIT_FAILURE
);
1075 _exit(EXIT_SUCCESS
);
1078 pair
[1] = safe_close(pair
[1]);
1080 r
= wait_for_terminate(child
, &si
);
1083 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1086 return receive_one_fd(pair
[0], 0);
1089 int open_terminal_in_namespace(pid_t pid
, const char *name
, int mode
) {
1090 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1091 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1096 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1100 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1110 pair
[0] = safe_close(pair
[0]);
1112 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1114 _exit(EXIT_FAILURE
);
1116 master
= open_terminal(name
, mode
|O_NOCTTY
|O_CLOEXEC
);
1118 _exit(EXIT_FAILURE
);
1120 if (send_one_fd(pair
[1], master
, 0) < 0)
1121 _exit(EXIT_FAILURE
);
1123 _exit(EXIT_SUCCESS
);
1126 pair
[1] = safe_close(pair
[1]);
1128 r
= wait_for_terminate(child
, &si
);
1131 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1134 return receive_one_fd(pair
[0], 0);
1137 bool colors_enabled(void) {
1140 colors
= getenv("SYSTEMD_COLORS");
1142 if (streq_ptr(getenv("TERM"), "dumb"))
1147 return parse_boolean(colors
) != 0;