1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 Copyright 2010-2013 Lennart Poettering
13 #include <sys/epoll.h>
14 #include <sys/ioctl.h>
21 #include "alloc-util.h"
26 #include "time-util.h"
33 PTYForwardFlags flags
;
35 sd_event_source
*stdin_event_source
;
36 sd_event_source
*stdout_event_source
;
37 sd_event_source
*master_event_source
;
39 sd_event_source
*sigwinch_event_source
;
41 struct termios saved_stdin_attr
;
42 struct termios saved_stdout_attr
;
47 bool stdin_readable
:1;
49 bool stdout_writable
:1;
51 bool master_readable
:1;
52 bool master_writable
:1;
55 bool read_from_master
:1;
63 char in_buffer
[LINE_MAX
], out_buffer
[LINE_MAX
];
64 size_t in_buffer_full
, out_buffer_full
;
66 usec_t escape_timestamp
;
67 unsigned escape_counter
;
69 PTYForwardHandler handler
;
73 #define ESCAPE_USEC (1*USEC_PER_SEC)
75 static void pty_forward_disconnect(PTYForward
*f
) {
78 f
->stdin_event_source
= sd_event_source_unref(f
->stdin_event_source
);
79 f
->stdout_event_source
= sd_event_source_unref(f
->stdout_event_source
);
81 f
->master_event_source
= sd_event_source_unref(f
->master_event_source
);
82 f
->sigwinch_event_source
= sd_event_source_unref(f
->sigwinch_event_source
);
83 f
->event
= sd_event_unref(f
->event
);
86 tcsetattr(STDOUT_FILENO
, TCSANOW
, &f
->saved_stdout_attr
);
88 tcsetattr(STDIN_FILENO
, TCSANOW
, &f
->saved_stdin_attr
);
90 f
->saved_stdout
= f
->saved_stdin
= false;
93 /* STDIN/STDOUT should not be nonblocking normally, so let's unconditionally reset it */
94 fd_nonblock(STDIN_FILENO
, false);
95 fd_nonblock(STDOUT_FILENO
, false);
98 static int pty_forward_done(PTYForward
*f
, int rcode
) {
99 _cleanup_(sd_event_unrefp
) sd_event
*e
= NULL
;
105 e
= sd_event_ref(f
->event
);
108 pty_forward_disconnect(f
);
111 return f
->handler(f
, rcode
, f
->userdata
);
113 return sd_event_exit(e
, rcode
< 0 ? EXIT_FAILURE
: rcode
);
116 static bool look_for_escape(PTYForward
*f
, const char *buffer
, size_t n
) {
123 for (p
= buffer
; p
< buffer
+ n
; p
++) {
127 usec_t nw
= now(CLOCK_MONOTONIC
);
129 if (f
->escape_counter
== 0 || nw
> f
->escape_timestamp
+ ESCAPE_USEC
) {
130 f
->escape_timestamp
= nw
;
131 f
->escape_counter
= 1;
133 (f
->escape_counter
)++;
135 if (f
->escape_counter
>= 3)
139 f
->escape_timestamp
= 0;
140 f
->escape_counter
= 0;
147 static bool ignore_vhangup(PTYForward
*f
) {
150 if (f
->flags
& PTY_FORWARD_IGNORE_VHANGUP
)
153 if ((f
->flags
& PTY_FORWARD_IGNORE_INITIAL_VHANGUP
) && !f
->read_from_master
)
159 static bool drained(PTYForward
*f
) {
164 if (f
->out_buffer_full
> 0)
167 if (f
->master_readable
)
170 if (ioctl(f
->master
, TIOCINQ
, &q
) < 0)
171 log_debug_errno(errno
, "TIOCINQ failed on master: %m");
175 if (ioctl(f
->master
, TIOCOUTQ
, &q
) < 0)
176 log_debug_errno(errno
, "TIOCOUTQ failed on master: %m");
183 static int shovel(PTYForward
*f
) {
188 while ((f
->stdin_readable
&& f
->in_buffer_full
<= 0) ||
189 (f
->master_writable
&& f
->in_buffer_full
> 0) ||
190 (f
->master_readable
&& f
->out_buffer_full
<= 0) ||
191 (f
->stdout_writable
&& f
->out_buffer_full
> 0)) {
193 if (f
->stdin_readable
&& f
->in_buffer_full
< LINE_MAX
) {
195 k
= read(STDIN_FILENO
, f
->in_buffer
+ f
->in_buffer_full
, LINE_MAX
- f
->in_buffer_full
);
199 f
->stdin_readable
= false;
200 else if (IN_SET(errno
, EIO
, EPIPE
, ECONNRESET
)) {
201 f
->stdin_readable
= false;
202 f
->stdin_hangup
= true;
204 f
->stdin_event_source
= sd_event_source_unref(f
->stdin_event_source
);
206 log_error_errno(errno
, "read(): %m");
207 return pty_forward_done(f
, -errno
);
211 f
->stdin_readable
= false;
212 f
->stdin_hangup
= true;
214 f
->stdin_event_source
= sd_event_source_unref(f
->stdin_event_source
);
216 /* Check if ^] has been pressed three times within one second. If we get this we quite
218 if (look_for_escape(f
, f
->in_buffer
+ f
->in_buffer_full
, k
))
219 return pty_forward_done(f
, -ECANCELED
);
221 f
->in_buffer_full
+= (size_t) k
;
225 if (f
->master_writable
&& f
->in_buffer_full
> 0) {
227 k
= write(f
->master
, f
->in_buffer
, f
->in_buffer_full
);
230 if (IN_SET(errno
, EAGAIN
, EIO
))
231 f
->master_writable
= false;
232 else if (IN_SET(errno
, EPIPE
, ECONNRESET
)) {
233 f
->master_writable
= f
->master_readable
= false;
234 f
->master_hangup
= true;
236 f
->master_event_source
= sd_event_source_unref(f
->master_event_source
);
238 log_error_errno(errno
, "write(): %m");
239 return pty_forward_done(f
, -errno
);
242 assert(f
->in_buffer_full
>= (size_t) k
);
243 memmove(f
->in_buffer
, f
->in_buffer
+ k
, f
->in_buffer_full
- k
);
244 f
->in_buffer_full
-= k
;
248 if (f
->master_readable
&& f
->out_buffer_full
< LINE_MAX
) {
250 k
= read(f
->master
, f
->out_buffer
+ f
->out_buffer_full
, LINE_MAX
- f
->out_buffer_full
);
253 /* Note that EIO on the master device
254 * might be caused by vhangup() or
255 * temporary closing of everything on
256 * the other side, we treat it like
257 * EAGAIN here and try again, unless
258 * ignore_vhangup is off. */
260 if (errno
== EAGAIN
|| (errno
== EIO
&& ignore_vhangup(f
)))
261 f
->master_readable
= false;
262 else if (IN_SET(errno
, EPIPE
, ECONNRESET
, EIO
)) {
263 f
->master_readable
= f
->master_writable
= false;
264 f
->master_hangup
= true;
266 f
->master_event_source
= sd_event_source_unref(f
->master_event_source
);
268 log_error_errno(errno
, "read(): %m");
269 return pty_forward_done(f
, -errno
);
272 f
->read_from_master
= true;
273 f
->out_buffer_full
+= (size_t) k
;
277 if (f
->stdout_writable
&& f
->out_buffer_full
> 0) {
279 k
= write(STDOUT_FILENO
, f
->out_buffer
, f
->out_buffer_full
);
283 f
->stdout_writable
= false;
284 else if (IN_SET(errno
, EIO
, EPIPE
, ECONNRESET
)) {
285 f
->stdout_writable
= false;
286 f
->stdout_hangup
= true;
287 f
->stdout_event_source
= sd_event_source_unref(f
->stdout_event_source
);
289 log_error_errno(errno
, "write(): %m");
290 return pty_forward_done(f
, -errno
);
296 f
->last_char
= f
->out_buffer
[k
-1];
297 f
->last_char_set
= true;
300 assert(f
->out_buffer_full
>= (size_t) k
);
301 memmove(f
->out_buffer
, f
->out_buffer
+ k
, f
->out_buffer_full
- k
);
302 f
->out_buffer_full
-= k
;
307 if (f
->stdin_hangup
|| f
->stdout_hangup
|| f
->master_hangup
) {
308 /* Exit the loop if any side hung up and if there's
309 * nothing more to write or nothing we could write. */
311 if ((f
->out_buffer_full
<= 0 || f
->stdout_hangup
) &&
312 (f
->in_buffer_full
<= 0 || f
->master_hangup
))
313 return pty_forward_done(f
, 0);
316 /* If we were asked to drain, and there's nothing more to handle from the master, then call the callback
318 if (f
->drain
&& drained(f
))
319 return pty_forward_done(f
, 0);
324 static int on_master_event(sd_event_source
*e
, int fd
, uint32_t revents
, void *userdata
) {
325 PTYForward
*f
= userdata
;
329 assert(e
== f
->master_event_source
);
331 assert(fd
== f
->master
);
333 if (revents
& (EPOLLIN
|EPOLLHUP
))
334 f
->master_readable
= true;
336 if (revents
& (EPOLLOUT
|EPOLLHUP
))
337 f
->master_writable
= true;
342 static int on_stdin_event(sd_event_source
*e
, int fd
, uint32_t revents
, void *userdata
) {
343 PTYForward
*f
= userdata
;
347 assert(e
== f
->stdin_event_source
);
349 assert(fd
== STDIN_FILENO
);
351 if (revents
& (EPOLLIN
|EPOLLHUP
))
352 f
->stdin_readable
= true;
357 static int on_stdout_event(sd_event_source
*e
, int fd
, uint32_t revents
, void *userdata
) {
358 PTYForward
*f
= userdata
;
362 assert(e
== f
->stdout_event_source
);
364 assert(fd
== STDOUT_FILENO
);
366 if (revents
& (EPOLLOUT
|EPOLLHUP
))
367 f
->stdout_writable
= true;
372 static int on_sigwinch_event(sd_event_source
*e
, const struct signalfd_siginfo
*si
, void *userdata
) {
373 PTYForward
*f
= userdata
;
378 assert(e
== f
->sigwinch_event_source
);
380 /* The window size changed, let's forward that. */
381 if (ioctl(STDOUT_FILENO
, TIOCGWINSZ
, &ws
) >= 0)
382 (void) ioctl(f
->master
, TIOCSWINSZ
, &ws
);
390 PTYForwardFlags flags
,
393 _cleanup_(pty_forward_freep
) PTYForward
*f
= NULL
;
397 f
= new0(PTYForward
, 1);
404 f
->event
= sd_event_ref(event
);
406 r
= sd_event_default(&f
->event
);
411 if (!(flags
& PTY_FORWARD_READ_ONLY
)) {
412 r
= fd_nonblock(STDIN_FILENO
, true);
416 r
= fd_nonblock(STDOUT_FILENO
, true);
421 r
= fd_nonblock(master
, true);
427 if (ioctl(STDOUT_FILENO
, TIOCGWINSZ
, &ws
) >= 0)
428 (void) ioctl(master
, TIOCSWINSZ
, &ws
);
430 if (!(flags
& PTY_FORWARD_READ_ONLY
)) {
431 if (tcgetattr(STDIN_FILENO
, &f
->saved_stdin_attr
) >= 0) {
432 struct termios raw_stdin_attr
;
434 f
->saved_stdin
= true;
436 raw_stdin_attr
= f
->saved_stdin_attr
;
437 cfmakeraw(&raw_stdin_attr
);
438 raw_stdin_attr
.c_oflag
= f
->saved_stdin_attr
.c_oflag
;
439 tcsetattr(STDIN_FILENO
, TCSANOW
, &raw_stdin_attr
);
442 if (tcgetattr(STDOUT_FILENO
, &f
->saved_stdout_attr
) >= 0) {
443 struct termios raw_stdout_attr
;
445 f
->saved_stdout
= true;
447 raw_stdout_attr
= f
->saved_stdout_attr
;
448 cfmakeraw(&raw_stdout_attr
);
449 raw_stdout_attr
.c_iflag
= f
->saved_stdout_attr
.c_iflag
;
450 raw_stdout_attr
.c_lflag
= f
->saved_stdout_attr
.c_lflag
;
451 tcsetattr(STDOUT_FILENO
, TCSANOW
, &raw_stdout_attr
);
454 r
= sd_event_add_io(f
->event
, &f
->stdin_event_source
, STDIN_FILENO
, EPOLLIN
|EPOLLET
, on_stdin_event
, f
);
455 if (r
< 0 && r
!= -EPERM
)
459 (void) sd_event_source_set_description(f
->stdin_event_source
, "ptyfwd-stdin");
462 r
= sd_event_add_io(f
->event
, &f
->stdout_event_source
, STDOUT_FILENO
, EPOLLOUT
|EPOLLET
, on_stdout_event
, f
);
464 /* stdout without epoll support. Likely redirected to regular file. */
465 f
->stdout_writable
= true;
469 (void) sd_event_source_set_description(f
->stdout_event_source
, "ptyfwd-stdout");
471 r
= sd_event_add_io(f
->event
, &f
->master_event_source
, master
, EPOLLIN
|EPOLLOUT
|EPOLLET
, on_master_event
, f
);
475 (void) sd_event_source_set_description(f
->master_event_source
, "ptyfwd-master");
477 r
= sd_event_add_signal(f
->event
, &f
->sigwinch_event_source
, SIGWINCH
, on_sigwinch_event
, f
);
481 (void) sd_event_source_set_description(f
->sigwinch_event_source
, "ptyfwd-sigwinch");
488 PTYForward
*pty_forward_free(PTYForward
*f
) {
489 pty_forward_disconnect(f
);
493 int pty_forward_get_last_char(PTYForward
*f
, char *ch
) {
497 if (!f
->last_char_set
)
504 int pty_forward_set_ignore_vhangup(PTYForward
*f
, bool b
) {
509 if (!!(f
->flags
& PTY_FORWARD_IGNORE_VHANGUP
) == b
)
512 SET_FLAG(f
->flags
, PTY_FORWARD_IGNORE_VHANGUP
, b
);
514 if (!ignore_vhangup(f
)) {
516 /* We shall now react to vhangup()s? Let's check
517 * immediately if we might be in one */
519 f
->master_readable
= true;
528 bool pty_forward_get_ignore_vhangup(PTYForward
*f
) {
531 return !!(f
->flags
& PTY_FORWARD_IGNORE_VHANGUP
);
534 bool pty_forward_is_done(PTYForward
*f
) {
540 void pty_forward_set_handler(PTYForward
*f
, PTYForwardHandler cb
, void *userdata
) {
544 f
->userdata
= userdata
;
547 bool pty_forward_drain(PTYForward
*f
) {
550 /* Starts draining the forwarder. Specifically:
552 * - Returns true if there are no unprocessed bytes from the pty, false otherwise
554 * - Makes sure the handler function is called the next time the number of unprocessed bytes hits zero
561 int pty_forward_set_priority(PTYForward
*f
, int64_t priority
) {
565 r
= sd_event_source_set_priority(f
->stdin_event_source
, priority
);
569 r
= sd_event_source_set_priority(f
->stdout_event_source
, priority
);
573 r
= sd_event_source_set_priority(f
->master_event_source
, priority
);
577 r
= sd_event_source_set_priority(f
->sigwinch_event_source
, priority
);