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4ba93280 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010-2013 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <sys/epoll.h> | |
23 | #include <sys/signalfd.h> | |
24 | #include <sys/ioctl.h> | |
25 | #include <limits.h> | |
26 | #include <termios.h> | |
27 | ||
28 | #include "util.h" | |
29 | #include "ptyfwd.h" | |
30 | ||
023fb90b LP |
31 | struct PTYForward { |
32 | sd_event *event; | |
04d39279 | 33 | |
023fb90b LP |
34 | int master; |
35 | ||
36 | sd_event_source *stdin_event_source; | |
37 | sd_event_source *stdout_event_source; | |
38 | sd_event_source *master_event_source; | |
39 | ||
40 | sd_event_source *sigwinch_event_source; | |
41 | ||
42 | struct termios saved_stdin_attr; | |
43 | struct termios saved_stdout_attr; | |
44 | ||
45 | bool saved_stdin:1; | |
46 | bool saved_stdout:1; | |
47 | ||
48 | bool stdin_readable:1; | |
49 | bool stdin_hangup:1; | |
50 | bool stdout_writable:1; | |
51 | bool stdout_hangup:1; | |
52 | bool master_readable:1; | |
53 | bool master_writable:1; | |
54 | bool master_hangup:1; | |
0ec5543c | 55 | bool master_suppressed_hangup:1; |
023fb90b | 56 | |
9b15b784 LP |
57 | bool repeat:1; |
58 | ||
59 | bool last_char_set:1; | |
60 | char last_char; | |
61 | ||
023fb90b LP |
62 | char in_buffer[LINE_MAX], out_buffer[LINE_MAX]; |
63 | size_t in_buffer_full, out_buffer_full; | |
64 | ||
65 | usec_t escape_timestamp; | |
66 | unsigned escape_counter; | |
67 | }; | |
68 | ||
69 | #define ESCAPE_USEC (1*USEC_PER_SEC) | |
70 | ||
71 | static bool look_for_escape(PTYForward *f, const char *buffer, size_t n) { | |
04d39279 LP |
72 | const char *p; |
73 | ||
023fb90b | 74 | assert(f); |
04d39279 LP |
75 | assert(buffer); |
76 | assert(n > 0); | |
77 | ||
78 | for (p = buffer; p < buffer + n; p++) { | |
79 | ||
80 | /* Check for ^] */ | |
81 | if (*p == 0x1D) { | |
82 | usec_t nw = now(CLOCK_MONOTONIC); | |
83 | ||
023fb90b LP |
84 | if (f->escape_counter == 0 || nw > f->escape_timestamp + ESCAPE_USEC) { |
85 | f->escape_timestamp = nw; | |
86 | f->escape_counter = 1; | |
04d39279 | 87 | } else { |
023fb90b | 88 | (f->escape_counter)++; |
04d39279 | 89 | |
023fb90b | 90 | if (f->escape_counter >= 3) |
04d39279 LP |
91 | return true; |
92 | } | |
93 | } else { | |
023fb90b LP |
94 | f->escape_timestamp = 0; |
95 | f->escape_counter = 0; | |
04d39279 LP |
96 | } |
97 | } | |
98 | ||
99 | return false; | |
100 | } | |
101 | ||
023fb90b LP |
102 | static int shovel(PTYForward *f) { |
103 | ssize_t k; | |
4ba93280 | 104 | |
023fb90b | 105 | assert(f); |
4ba93280 | 106 | |
023fb90b LP |
107 | while ((f->stdin_readable && f->in_buffer_full <= 0) || |
108 | (f->master_writable && f->in_buffer_full > 0) || | |
109 | (f->master_readable && f->out_buffer_full <= 0) || | |
110 | (f->stdout_writable && f->out_buffer_full > 0)) { | |
4ba93280 | 111 | |
023fb90b | 112 | if (f->stdin_readable && f->in_buffer_full < LINE_MAX) { |
4ba93280 | 113 | |
023fb90b LP |
114 | k = read(STDIN_FILENO, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full); |
115 | if (k < 0) { | |
4ba93280 | 116 | |
023fb90b LP |
117 | if (errno == EAGAIN) |
118 | f->stdin_readable = false; | |
119 | else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) { | |
120 | f->stdin_readable = false; | |
121 | f->stdin_hangup = true; | |
4ba93280 | 122 | |
023fb90b LP |
123 | f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); |
124 | } else { | |
56f64d95 | 125 | log_error_errno(errno, "read(): %m"); |
023fb90b LP |
126 | return sd_event_exit(f->event, EXIT_FAILURE); |
127 | } | |
128 | } else if (k == 0) { | |
129 | /* EOF on stdin */ | |
130 | f->stdin_readable = false; | |
131 | f->stdin_hangup = true; | |
132 | ||
133 | f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); | |
134 | } else { | |
135 | /* Check if ^] has been | |
136 | * pressed three times within | |
137 | * one second. If we get this | |
138 | * we quite immediately. */ | |
139 | if (look_for_escape(f, f->in_buffer + f->in_buffer_full, k)) | |
140 | return sd_event_exit(f->event, EXIT_FAILURE); | |
141 | ||
142 | f->in_buffer_full += (size_t) k; | |
143 | } | |
4ba93280 LP |
144 | } |
145 | ||
023fb90b | 146 | if (f->master_writable && f->in_buffer_full > 0) { |
4ba93280 | 147 | |
023fb90b LP |
148 | k = write(f->master, f->in_buffer, f->in_buffer_full); |
149 | if (k < 0) { | |
4ba93280 | 150 | |
023fb90b LP |
151 | if (errno == EAGAIN || errno == EIO) |
152 | f->master_writable = false; | |
153 | else if (errno == EPIPE || errno == ECONNRESET) { | |
154 | f->master_writable = f->master_readable = false; | |
155 | f->master_hangup = true; | |
4ba93280 | 156 | |
023fb90b LP |
157 | f->master_event_source = sd_event_source_unref(f->master_event_source); |
158 | } else { | |
56f64d95 | 159 | log_error_errno(errno, "write(): %m"); |
023fb90b LP |
160 | return sd_event_exit(f->event, EXIT_FAILURE); |
161 | } | |
162 | } else { | |
163 | assert(f->in_buffer_full >= (size_t) k); | |
164 | memmove(f->in_buffer, f->in_buffer + k, f->in_buffer_full - k); | |
165 | f->in_buffer_full -= k; | |
166 | } | |
4ba93280 LP |
167 | } |
168 | ||
023fb90b | 169 | if (f->master_readable && f->out_buffer_full < LINE_MAX) { |
4ba93280 | 170 | |
023fb90b LP |
171 | k = read(f->master, f->out_buffer + f->out_buffer_full, LINE_MAX - f->out_buffer_full); |
172 | if (k < 0) { | |
4ba93280 | 173 | |
0ec5543c LP |
174 | if (errno == EAGAIN) |
175 | f->master_readable = false; | |
176 | ||
177 | else if (errno == EIO && f->repeat) { | |
178 | ||
179 | /* Note that EIO on the master device | |
180 | * might be cause by vhangup() or | |
181 | * temporary closing of everything on | |
182 | * the other side, we treat it like | |
183 | * EAGAIN here and try again, unless | |
184 | * repeat is off. */ | |
4ba93280 | 185 | |
023fb90b | 186 | f->master_readable = false; |
0ec5543c LP |
187 | f->master_suppressed_hangup = true; |
188 | ||
189 | } else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) { | |
023fb90b LP |
190 | f->master_readable = f->master_writable = false; |
191 | f->master_hangup = true; | |
4ba93280 | 192 | |
023fb90b | 193 | f->master_event_source = sd_event_source_unref(f->master_event_source); |
04d39279 | 194 | } else { |
56f64d95 | 195 | log_error_errno(errno, "read(): %m"); |
023fb90b | 196 | return sd_event_exit(f->event, EXIT_FAILURE); |
04d39279 | 197 | } |
023fb90b LP |
198 | } else |
199 | f->out_buffer_full += (size_t) k; | |
200 | } | |
4ba93280 | 201 | |
023fb90b | 202 | if (f->stdout_writable && f->out_buffer_full > 0) { |
4ba93280 | 203 | |
023fb90b LP |
204 | k = write(STDOUT_FILENO, f->out_buffer, f->out_buffer_full); |
205 | if (k < 0) { | |
4ba93280 | 206 | |
023fb90b LP |
207 | if (errno == EAGAIN) |
208 | f->stdout_writable = false; | |
209 | else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) { | |
210 | f->stdout_writable = false; | |
211 | f->stdout_hangup = true; | |
212 | f->stdout_event_source = sd_event_source_unref(f->stdout_event_source); | |
4ba93280 | 213 | } else { |
56f64d95 | 214 | log_error_errno(errno, "write(): %m"); |
023fb90b | 215 | return sd_event_exit(f->event, EXIT_FAILURE); |
4ba93280 | 216 | } |
4ba93280 | 217 | |
023fb90b | 218 | } else { |
9b15b784 LP |
219 | |
220 | if (k > 0) { | |
221 | f->last_char = f->out_buffer[k-1]; | |
222 | f->last_char_set = true; | |
223 | } | |
224 | ||
023fb90b LP |
225 | assert(f->out_buffer_full >= (size_t) k); |
226 | memmove(f->out_buffer, f->out_buffer + k, f->out_buffer_full - k); | |
227 | f->out_buffer_full -= k; | |
4ba93280 | 228 | } |
023fb90b LP |
229 | } |
230 | } | |
231 | ||
232 | if (f->stdin_hangup || f->stdout_hangup || f->master_hangup) { | |
233 | /* Exit the loop if any side hung up and if there's | |
234 | * nothing more to write or nothing we could write. */ | |
4ba93280 | 235 | |
023fb90b LP |
236 | if ((f->out_buffer_full <= 0 || f->stdout_hangup) && |
237 | (f->in_buffer_full <= 0 || f->master_hangup)) | |
238 | return sd_event_exit(f->event, EXIT_SUCCESS); | |
239 | } | |
4ba93280 | 240 | |
023fb90b LP |
241 | return 0; |
242 | } | |
4ba93280 | 243 | |
023fb90b LP |
244 | static int on_master_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
245 | PTYForward *f = userdata; | |
4ba93280 | 246 | |
023fb90b LP |
247 | assert(f); |
248 | assert(e); | |
249 | assert(e == f->master_event_source); | |
250 | assert(fd >= 0); | |
251 | assert(fd == f->master); | |
04d39279 | 252 | |
0ec5543c LP |
253 | f->master_suppressed_hangup = false; |
254 | ||
023fb90b LP |
255 | if (revents & (EPOLLIN|EPOLLHUP)) |
256 | f->master_readable = true; | |
04d39279 | 257 | |
023fb90b LP |
258 | if (revents & (EPOLLOUT|EPOLLHUP)) |
259 | f->master_writable = true; | |
04d39279 | 260 | |
023fb90b LP |
261 | return shovel(f); |
262 | } | |
04d39279 | 263 | |
023fb90b LP |
264 | static int on_stdin_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
265 | PTYForward *f = userdata; | |
04d39279 | 266 | |
023fb90b LP |
267 | assert(f); |
268 | assert(e); | |
269 | assert(e == f->stdin_event_source); | |
270 | assert(fd >= 0); | |
271 | assert(fd == STDIN_FILENO); | |
04d39279 | 272 | |
023fb90b LP |
273 | if (revents & (EPOLLIN|EPOLLHUP)) |
274 | f->stdin_readable = true; | |
04d39279 | 275 | |
023fb90b LP |
276 | return shovel(f); |
277 | } | |
04d39279 | 278 | |
023fb90b LP |
279 | static int on_stdout_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
280 | PTYForward *f = userdata; | |
04d39279 | 281 | |
023fb90b LP |
282 | assert(f); |
283 | assert(e); | |
284 | assert(e == f->stdout_event_source); | |
285 | assert(fd >= 0); | |
286 | assert(fd == STDOUT_FILENO); | |
04d39279 | 287 | |
023fb90b LP |
288 | if (revents & (EPOLLOUT|EPOLLHUP)) |
289 | f->stdout_writable = true; | |
04d39279 | 290 | |
023fb90b LP |
291 | return shovel(f); |
292 | } | |
04d39279 | 293 | |
023fb90b LP |
294 | static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *si, void *userdata) { |
295 | PTYForward *f = userdata; | |
296 | struct winsize ws; | |
04d39279 | 297 | |
023fb90b LP |
298 | assert(f); |
299 | assert(e); | |
300 | assert(e == f->sigwinch_event_source); | |
301 | ||
302 | /* The window size changed, let's forward that. */ | |
303 | if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0) | |
7c63b23f | 304 | (void)ioctl(f->master, TIOCSWINSZ, &ws); |
023fb90b LP |
305 | |
306 | return 0; | |
4ba93280 | 307 | } |
04d39279 | 308 | |
9b15b784 | 309 | int pty_forward_new(sd_event *event, int master, bool repeat, PTYForward **ret) { |
023fb90b | 310 | _cleanup_(pty_forward_freep) PTYForward *f = NULL; |
04d39279 LP |
311 | struct winsize ws; |
312 | int r; | |
313 | ||
023fb90b LP |
314 | f = new0(PTYForward, 1); |
315 | if (!f) | |
316 | return -ENOMEM; | |
317 | ||
9b15b784 LP |
318 | f->repeat = repeat; |
319 | ||
023fb90b LP |
320 | if (event) |
321 | f->event = sd_event_ref(event); | |
322 | else { | |
323 | r = sd_event_default(&f->event); | |
324 | if (r < 0) | |
325 | return r; | |
326 | } | |
327 | ||
328 | r = fd_nonblock(STDIN_FILENO, true); | |
329 | if (r < 0) | |
330 | return r; | |
331 | ||
332 | r = fd_nonblock(STDOUT_FILENO, true); | |
333 | if (r < 0) | |
334 | return r; | |
335 | ||
336 | r = fd_nonblock(master, true); | |
337 | if (r < 0) | |
338 | return r; | |
339 | ||
340 | f->master = master; | |
341 | ||
eaf73b06 | 342 | if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0) |
7c63b23f | 343 | (void)ioctl(master, TIOCSWINSZ, &ws); |
04d39279 | 344 | |
023fb90b LP |
345 | if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) { |
346 | struct termios raw_stdin_attr; | |
04d39279 | 347 | |
023fb90b LP |
348 | f->saved_stdin = true; |
349 | ||
350 | raw_stdin_attr = f->saved_stdin_attr; | |
90d14d20 | 351 | cfmakeraw(&raw_stdin_attr); |
023fb90b | 352 | raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag; |
90d14d20 LS |
353 | tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr); |
354 | } | |
90d14d20 | 355 | |
023fb90b LP |
356 | if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) { |
357 | struct termios raw_stdout_attr; | |
358 | ||
359 | f->saved_stdout = true; | |
360 | ||
361 | raw_stdout_attr = f->saved_stdout_attr; | |
90d14d20 | 362 | cfmakeraw(&raw_stdout_attr); |
023fb90b LP |
363 | raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag; |
364 | raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag; | |
90d14d20 | 365 | tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr); |
04d39279 LP |
366 | } |
367 | ||
023fb90b LP |
368 | r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f); |
369 | if (r < 0) | |
370 | return r; | |
04d39279 | 371 | |
023fb90b LP |
372 | r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f); |
373 | if (r < 0 && r != -EPERM) | |
374 | return r; | |
375 | ||
376 | r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f); | |
377 | if (r == -EPERM) | |
378 | /* stdout without epoll support. Likely redirected to regular file. */ | |
379 | f->stdout_writable = true; | |
380 | else if (r < 0) | |
381 | return r; | |
382 | ||
383 | r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f); | |
384 | ||
385 | *ret = f; | |
386 | f = NULL; | |
387 | ||
388 | return 0; | |
389 | } | |
390 | ||
391 | PTYForward *pty_forward_free(PTYForward *f) { | |
392 | ||
393 | if (f) { | |
394 | sd_event_source_unref(f->stdin_event_source); | |
395 | sd_event_source_unref(f->stdout_event_source); | |
396 | sd_event_source_unref(f->master_event_source); | |
397 | sd_event_unref(f->event); | |
398 | ||
399 | if (f->saved_stdout) | |
400 | tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr); | |
401 | if (f->saved_stdin) | |
402 | tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr); | |
403 | ||
404 | free(f); | |
405 | } | |
04d39279 | 406 | |
d60473c7 LP |
407 | /* STDIN/STDOUT should not be nonblocking normally, so let's |
408 | * unconditionally reset it */ | |
409 | fd_nonblock(STDIN_FILENO, false); | |
410 | fd_nonblock(STDOUT_FILENO, false); | |
411 | ||
023fb90b | 412 | return NULL; |
04d39279 | 413 | } |
9b15b784 | 414 | |
0ec5543c | 415 | int pty_forward_get_last_char(PTYForward *f, char *ch) { |
9b15b784 LP |
416 | assert(f); |
417 | assert(ch); | |
418 | ||
419 | if (!f->last_char_set) | |
420 | return -ENXIO; | |
421 | ||
422 | *ch = f->last_char; | |
423 | return 0; | |
424 | } | |
0ec5543c LP |
425 | |
426 | int pty_forward_set_repeat(PTYForward *f, bool repeat) { | |
427 | int r; | |
428 | ||
429 | assert(f); | |
430 | ||
431 | if (f->repeat == repeat) | |
432 | return 0; | |
433 | ||
434 | f->repeat = repeat; | |
435 | ||
436 | /* Are we currently in a suppress hangup phase? If so, let's | |
437 | * immediately terminate things */ | |
438 | if (!f->repeat && f->master_suppressed_hangup) { | |
439 | ||
440 | /* Let's try to read again from the master fd, and if | |
441 | * it is this will now cause termination of the | |
442 | * session. */ | |
443 | ||
444 | f->master_readable = true; | |
445 | r = shovel(f); | |
446 | if (r < 0) | |
447 | return r; | |
448 | } | |
449 | ||
450 | return 0; | |
451 | } | |
452 | ||
453 | int pty_forward_get_repeat(PTYForward *f) { | |
454 | assert(f); | |
455 | ||
456 | return f->repeat; | |
457 | } |