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"
58 #include "path-util.h"
60 static volatile unsigned cached_columns
= 0;
61 static volatile unsigned cached_lines
= 0;
64 _cleanup_close_
int fd
;
66 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
72 TIOCL_GETKMSGREDIRECT
,
76 if (ioctl(fd
, TIOCLINUX
, tiocl
) < 0)
79 vt
= tiocl
[0] <= 0 ? 1 : tiocl
[0];
82 if (ioctl(fd
, VT_ACTIVATE
, vt
) < 0)
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
;
248 _cleanup_free_
char *utf8
= NULL
;
252 /* Set terminal to some sane defaults */
256 /* We leave locked terminal attributes untouched, so that
257 * Plymouth may set whatever it wants to set, and we don't
258 * interfere with that. */
260 /* Disable exclusive mode, just in case */
261 (void) ioctl(fd
, TIOCNXCL
);
263 /* Switch to text mode */
265 (void) ioctl(fd
, KDSETMODE
, KD_TEXT
);
267 /* Set default keyboard mode */
268 if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8
) >= 0 && parse_boolean(utf8
) == 0)
272 (void) ioctl(fd
, KDSKBMODE
, kb
);
274 if (tcgetattr(fd
, &termios
) < 0) {
279 /* We only reset the stuff that matters to the software. How
280 * hardware is set up we don't touch assuming that somebody
281 * else will do that for us */
283 termios
.c_iflag
&= ~(IGNBRK
| BRKINT
| ISTRIP
| INLCR
| IGNCR
| IUCLC
);
284 termios
.c_iflag
|= ICRNL
| IMAXBEL
| IUTF8
;
285 termios
.c_oflag
|= ONLCR
;
286 termios
.c_cflag
|= CREAD
;
287 termios
.c_lflag
= ISIG
| ICANON
| IEXTEN
| ECHO
| ECHOE
| ECHOK
| ECHOCTL
| ECHOPRT
| ECHOKE
;
289 termios
.c_cc
[VINTR
] = 03; /* ^C */
290 termios
.c_cc
[VQUIT
] = 034; /* ^\ */
291 termios
.c_cc
[VERASE
] = 0177;
292 termios
.c_cc
[VKILL
] = 025; /* ^X */
293 termios
.c_cc
[VEOF
] = 04; /* ^D */
294 termios
.c_cc
[VSTART
] = 021; /* ^Q */
295 termios
.c_cc
[VSTOP
] = 023; /* ^S */
296 termios
.c_cc
[VSUSP
] = 032; /* ^Z */
297 termios
.c_cc
[VLNEXT
] = 026; /* ^V */
298 termios
.c_cc
[VWERASE
] = 027; /* ^W */
299 termios
.c_cc
[VREPRINT
] = 022; /* ^R */
300 termios
.c_cc
[VEOL
] = 0;
301 termios
.c_cc
[VEOL2
] = 0;
303 termios
.c_cc
[VTIME
] = 0;
304 termios
.c_cc
[VMIN
] = 1;
306 if (tcsetattr(fd
, TCSANOW
, &termios
) < 0)
310 /* Just in case, flush all crap out */
311 (void) tcflush(fd
, TCIOFLUSH
);
316 int reset_terminal(const char *name
) {
317 _cleanup_close_
int fd
= -1;
319 /* We open the terminal with O_NONBLOCK here, to ensure we
320 * don't block on carrier if this is a terminal with carrier
323 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
327 return reset_terminal_fd(fd
, true);
330 int open_terminal(const char *name
, int mode
) {
335 * If a TTY is in the process of being closed opening it might
336 * cause EIO. This is horribly awful, but unlikely to be
337 * changed in the kernel. Hence we work around this problem by
338 * retrying a couple of times.
340 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
347 fd
= open(name
, mode
, 0);
354 /* Max 1s in total */
358 usleep(50 * USEC_PER_MSEC
);
371 int acquire_terminal(
375 bool ignore_tiocstty_eperm
,
378 int fd
= -1, notify
= -1, r
= 0, wd
= -1;
383 /* We use inotify to be notified when the tty is closed. We
384 * create the watch before checking if we can actually acquire
385 * it, so that we don't lose any event.
387 * Note: strictly speaking this actually watches for the
388 * device being closed, it does *not* really watch whether a
389 * tty loses its controlling process. However, unless some
390 * rogue process uses TIOCNOTTY on /dev/tty *after* closing
391 * its tty otherwise this will not become a problem. As long
392 * as the administrator makes sure not configure any service
393 * on the same tty as an untrusted user this should not be a
394 * problem. (Which he probably should not do anyway.) */
396 if (timeout
!= USEC_INFINITY
)
397 ts
= now(CLOCK_MONOTONIC
);
399 if (!fail
&& !force
) {
400 notify
= inotify_init1(IN_CLOEXEC
| (timeout
!= USEC_INFINITY
? IN_NONBLOCK
: 0));
406 wd
= inotify_add_watch(notify
, name
, IN_CLOSE
);
414 struct sigaction sa_old
, sa_new
= {
415 .sa_handler
= SIG_IGN
,
416 .sa_flags
= SA_RESTART
,
420 r
= flush_fd(notify
);
425 /* We pass here O_NOCTTY only so that we can check the return
426 * value TIOCSCTTY and have a reliable way to figure out if we
427 * successfully became the controlling process of the tty */
428 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
432 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
433 * if we already own the tty. */
434 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
436 /* First, try to get the tty */
437 if (ioctl(fd
, TIOCSCTTY
, force
) < 0)
440 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
442 /* Sometimes, it makes sense to ignore TIOCSCTTY
443 * returning EPERM, i.e. when very likely we already
444 * are have this controlling terminal. */
445 if (r
< 0 && r
== -EPERM
&& ignore_tiocstty_eperm
)
448 if (r
< 0 && (force
|| fail
|| r
!= -EPERM
))
459 union inotify_event_buffer buffer
;
460 struct inotify_event
*e
;
463 if (timeout
!= USEC_INFINITY
) {
466 n
= now(CLOCK_MONOTONIC
);
467 if (ts
+ timeout
< n
) {
472 r
= fd_wait_for_event(notify
, POLLIN
, ts
+ timeout
- n
);
482 l
= read(notify
, &buffer
, sizeof(buffer
));
484 if (errno
== EINTR
|| errno
== EAGAIN
)
491 FOREACH_INOTIFY_EVENT(e
, buffer
, l
) {
492 if (e
->wd
!= wd
|| !(e
->mask
& IN_CLOSE
)) {
501 /* We close the tty fd here since if the old session
502 * ended our handle will be dead. It's important that
503 * we do this after sleeping, so that we don't enter
504 * an endless loop. */
519 int release_terminal(void) {
520 static const struct sigaction sa_new
= {
521 .sa_handler
= SIG_IGN
,
522 .sa_flags
= SA_RESTART
,
525 _cleanup_close_
int fd
= -1;
526 struct sigaction sa_old
;
529 fd
= open("/dev/tty", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
533 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
534 * by our own TIOCNOTTY */
535 assert_se(sigaction(SIGHUP
, &sa_new
, &sa_old
) == 0);
537 if (ioctl(fd
, TIOCNOTTY
) < 0)
540 assert_se(sigaction(SIGHUP
, &sa_old
, NULL
) == 0);
545 int terminal_vhangup_fd(int fd
) {
548 if (ioctl(fd
, TIOCVHANGUP
) < 0)
554 int terminal_vhangup(const char *name
) {
555 _cleanup_close_
int fd
;
557 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
561 return terminal_vhangup_fd(fd
);
564 int vt_disallocate(const char *name
) {
565 _cleanup_close_
int fd
= -1;
570 /* Deallocate the VT if possible. If not possible
571 * (i.e. because it is the active one), at least clear it
572 * entirely (including the scrollback buffer) */
574 e
= path_startswith(name
, "/dev/");
578 if (!tty_is_vc(name
)) {
579 /* So this is not a VT. I guess we cannot deallocate
580 * it then. But let's at least clear the screen */
582 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
587 "\033[r" /* clear scrolling region */
588 "\033[H" /* move home */
589 "\033[2J", /* clear screen */
594 n
= startswith(e
, "tty");
598 r
= safe_atou(n
, &u
);
605 /* Try to deallocate */
606 fd
= open_terminal("/dev/tty0", O_RDWR
|O_NOCTTY
|O_CLOEXEC
|O_NONBLOCK
);
610 r
= ioctl(fd
, VT_DISALLOCATE
, u
);
619 /* Couldn't deallocate, so let's clear it fully with
621 fd
= open_terminal(name
, O_RDWR
|O_NOCTTY
|O_CLOEXEC
);
626 "\033[r" /* clear scrolling region */
627 "\033[H" /* move home */
628 "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
633 int make_console_stdio(void) {
636 /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
638 fd
= acquire_terminal("/dev/console", false, true, true, USEC_INFINITY
);
640 return log_error_errno(fd
, "Failed to acquire terminal: %m");
642 r
= reset_terminal_fd(fd
, true);
644 log_warning_errno(r
, "Failed to reset terminal, ignoring: %m");
648 return log_error_errno(r
, "Failed to duplicate terminal fd: %m");
653 bool tty_is_vc(const char *tty
) {
656 return vtnr_from_tty(tty
) >= 0;
659 bool tty_is_console(const char *tty
) {
662 return streq(skip_dev_prefix(tty
), "console");
665 int vtnr_from_tty(const char *tty
) {
670 tty
= skip_dev_prefix(tty
);
672 if (!startswith(tty
, "tty") )
675 if (tty
[3] < '0' || tty
[3] > '9')
678 r
= safe_atoi(tty
+3, &i
);
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";
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 void columns_lines_cache_reset(int signum
) {
874 static int cached_on_tty
= -1;
876 if (_unlikely_(cached_on_tty
< 0))
877 cached_on_tty
= isatty(STDOUT_FILENO
) > 0;
879 return cached_on_tty
;
882 int make_stdio(int fd
) {
887 r
= dup2(fd
, STDIN_FILENO
);
888 s
= dup2(fd
, STDOUT_FILENO
);
889 t
= dup2(fd
, STDERR_FILENO
);
894 if (r
< 0 || s
< 0 || t
< 0)
897 /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
898 * dup2() was a NOP and the bit hence possibly set. */
899 stdio_unset_cloexec();
904 int make_null_stdio(void) {
907 null_fd
= open("/dev/null", O_RDWR
|O_NOCTTY
);
911 return make_stdio(null_fd
);
914 int getttyname_malloc(int fd
, char **ret
) {
924 r
= ttyname_r(fd
, path
, sizeof(path
));
928 c
= strdup(skip_dev_prefix(path
));
945 int getttyname_harder(int fd
, char **r
) {
949 k
= getttyname_malloc(fd
, &s
);
953 if (streq(s
, "tty")) {
955 return get_ctty(0, NULL
, r
);
962 int get_ctty_devnr(pid_t pid
, dev_t
*d
) {
964 _cleanup_free_
char *line
= NULL
;
970 p
= procfs_file_alloca(pid
, "stat");
971 r
= read_one_line_file(p
, &line
);
975 p
= strrchr(line
, ')');
990 if (major(ttynr
) == 0 && minor(ttynr
) == 0)
999 int get_ctty(pid_t pid
, dev_t
*_devnr
, char **r
) {
1000 char fn
[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b
= NULL
;
1001 _cleanup_free_
char *s
= NULL
;
1008 k
= get_ctty_devnr(pid
, &devnr
);
1012 sprintf(fn
, "/dev/char/%u:%u", major(devnr
), minor(devnr
));
1014 k
= readlink_malloc(fn
, &s
);
1020 /* This is an ugly hack */
1021 if (major(devnr
) == 136) {
1022 if (asprintf(&b
, "pts/%u", minor(devnr
)) < 0)
1025 /* Probably something like the ptys which have no
1026 * symlink in /dev/char. Let's return something
1027 * vaguely useful. */
1034 if (startswith(s
, "/dev/"))
1036 else if (startswith(s
, "../"))
1053 int ptsname_malloc(int fd
, char **ret
) {
1066 if (ptsname_r(fd
, c
, l
) == 0) {
1070 if (errno
!= ERANGE
) {
1080 int ptsname_namespace(int pty
, char **ret
) {
1083 /* Like ptsname(), but doesn't assume that the path is
1084 * accessible in the local namespace. */
1086 r
= ioctl(pty
, TIOCGPTN
, &no
);
1093 if (asprintf(ret
, "/dev/pts/%i", no
) < 0)
1099 int openpt_in_namespace(pid_t pid
, int flags
) {
1100 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1101 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1108 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1112 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1122 pair
[0] = safe_close(pair
[0]);
1124 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1126 _exit(EXIT_FAILURE
);
1128 master
= posix_openpt(flags
|O_NOCTTY
|O_CLOEXEC
);
1130 _exit(EXIT_FAILURE
);
1132 if (unlockpt(master
) < 0)
1133 _exit(EXIT_FAILURE
);
1135 if (send_one_fd(pair
[1], master
, 0) < 0)
1136 _exit(EXIT_FAILURE
);
1138 _exit(EXIT_SUCCESS
);
1141 pair
[1] = safe_close(pair
[1]);
1143 r
= wait_for_terminate(child
, &si
);
1146 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1149 return receive_one_fd(pair
[0], 0);
1152 int open_terminal_in_namespace(pid_t pid
, const char *name
, int mode
) {
1153 _cleanup_close_
int pidnsfd
= -1, mntnsfd
= -1, usernsfd
= -1, rootfd
= -1;
1154 _cleanup_close_pair_
int pair
[2] = { -1, -1 };
1159 r
= namespace_open(pid
, &pidnsfd
, &mntnsfd
, NULL
, &usernsfd
, &rootfd
);
1163 if (socketpair(AF_UNIX
, SOCK_DGRAM
, 0, pair
) < 0)
1173 pair
[0] = safe_close(pair
[0]);
1175 r
= namespace_enter(pidnsfd
, mntnsfd
, -1, usernsfd
, rootfd
);
1177 _exit(EXIT_FAILURE
);
1179 master
= open_terminal(name
, mode
|O_NOCTTY
|O_CLOEXEC
);
1181 _exit(EXIT_FAILURE
);
1183 if (send_one_fd(pair
[1], master
, 0) < 0)
1184 _exit(EXIT_FAILURE
);
1186 _exit(EXIT_SUCCESS
);
1189 pair
[1] = safe_close(pair
[1]);
1191 r
= wait_for_terminate(child
, &si
);
1194 if (si
.si_code
!= CLD_EXITED
|| si
.si_status
!= EXIT_SUCCESS
)
1197 return receive_one_fd(pair
[0], 0);
1200 static bool getenv_terminal_is_dumb(void) {
1207 return streq(e
, "dumb");
1210 bool terminal_is_dumb(void) {
1214 return getenv_terminal_is_dumb();
1217 bool colors_enabled(void) {
1218 static int enabled
= -1;
1220 if (_unlikely_(enabled
< 0)) {
1223 val
= getenv_bool("SYSTEMD_COLORS");
1226 else if (getpid_cached() == 1)
1227 /* PID1 outputs to the console without holding it open all the time */
1228 enabled
= !getenv_terminal_is_dumb();
1230 enabled
= !terminal_is_dumb();