aboutsummaryrefslogtreecommitdiff
path: root/miscutils/chat.c
blob: 50c5ad976c63934b2158ed64fead1670dc4002aa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
/* vi: set sw=4 ts=4: */
/*
 * bare bones chat utility
 * inspired by ppp's chat
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 */
#include "libbb.h"

/*
#define ENABLE_FEATURE_CHAT_NOFAIL              1 // +126 bytes
#define ENABLE_FEATURE_CHAT_TTY_HIFI            0 // + 70 bytes
#define ENABLE_FEATURE_CHAT_IMPLICIT_CR         1 // + 44 bytes
#define ENABLE_FEATURE_CHAT_SEND_ESCAPES        0 // +103 bytes
#define ENABLE_FEATURE_CHAT_VAR_ABORT_LEN       0 // + 70 bytes
#define ENABLE_FEATURE_CHAT_CLR_ABORT           0 // +113 bytes
#define ENABLE_FEATURE_CHAT_SWALLOW_OPTS        0 // + 23 bytes
*/

// default timeout: 45 sec
#define	DEFAULT_CHAT_TIMEOUT 45*1000
// max length of "abort string",
// i.e. device reply which causes termination
#define MAX_ABORT_LEN 50

// possible exit codes
enum {
	ERR_OK = 0,     // all's well
	ERR_MEM,        // read too much while expecting
	ERR_IO,         // signalled or I/O error
	ERR_TIMEOUT,    // timed out while expecting
	ERR_ABORT,      // first abort condition was met
//	ERR_ABORT2,     // second abort condition was met
//	...
};

// exit code
// N.B> 10 bytes for volatile. Why all these signals?!
static /*volatile*/ smallint exitcode;

// trap for critical signals
static void signal_handler(ATTRIBUTE_UNUSED int signo)
{
	// report I/O error condition
	exitcode = ERR_IO;
}

#if !ENABLE_FEATURE_CHAT_IMPLICIT_CR
#define unescape(s, nocr) unescape(s)
#endif
static size_t unescape(char *s, int *nocr)
{
	char *start = s;
	char *p = s;

	while (*s) {
		char c = *s;
		// do we need special processing?
		// standard escapes + \s for space and \N for \0
		// \c inhibits terminating \r for commands and is noop for expects
		if ('\\' == c) {
			c = *++s;
			if (c) {
#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
				if ('c' == c) {
					*nocr = 1;
					goto next;
				}
#endif
				if ('N' == c) {
					c = '\0';
				} else if ('s' == c) {
					c = ' ';
#if ENABLE_FEATURE_CHAT_NOFAIL
				// unescape leading dash only
				// TODO: and only for expect, not command string
				} else if ('-' == c && (start + 1 == s)) {
					//c = '-';
#endif
				} else {
					c = bb_process_escape_sequence((const char **)&s);
					s--;
				}
			}
		// ^A becomes \001, ^B -- \002 and so on...
		} else if ('^' == c) {
			c = *++s-'@';
		}
		// put unescaped char
		*p++ = c;
#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
 next:
#endif
		// next char
		s++;
	}
	*p = '\0';

	return p - start;
}


int chat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chat_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
// should we dump device output? to what fd? by default no.
// this can be controlled later via ECHO {ON|OFF} chat directive
//	int echo_fd;
	bool echo = 0;
	// collection of device replies which cause unconditional termination
	llist_t *aborts = NULL;
	// inactivity period
	int timeout = DEFAULT_CHAT_TIMEOUT;
	// maximum length of abort string
#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
	size_t max_abort_len = 0;
#else
#define max_abort_len MAX_ABORT_LEN
#endif
#if ENABLE_FEATURE_CHAT_TTY_HIFI
	struct termios tio0, tio;
#endif
	// directive names
	enum {
		DIR_HANGUP = 0,
		DIR_ABORT,
#if ENABLE_FEATURE_CHAT_CLR_ABORT
		DIR_CLR_ABORT,
#endif
		DIR_TIMEOUT,
		DIR_ECHO,
		DIR_SAY,
	};

	// make x* functions fail with correct exitcode
	xfunc_error_retval = ERR_IO;

	// trap vanilla signals to prevent process from being killed suddenly
	bb_signals(0
		+ (1 << SIGHUP)
		+ (1 << SIGINT)
		+ (1 << SIGTERM)
		+ (1 << SIGPIPE)
		, signal_handler);

#if ENABLE_FEATURE_CHAT_TTY_HIFI
	tcgetattr(STDIN_FILENO, &tio);
	tio0 = tio;
	cfmakeraw(&tio);
	tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
#endif

#if ENABLE_FEATURE_CHAT_SWALLOW_OPTS
	getopt32(argv, "vVsSE");
	argv += optind;
#else
	argv++; // goto first arg
#endif
	// handle chat expect-send pairs
	while (*argv) {
		// directive given? process it
		int key = index_in_strings(
			"HANGUP\0" "ABORT\0"
#if ENABLE_FEATURE_CHAT_CLR_ABORT
			"CLR_ABORT\0"
#endif
			"TIMEOUT\0" "ECHO\0" "SAY\0"
			, *argv
		);
		if (key >= 0) {
			// cache directive value
			char *arg = *++argv;
			// ON -> 1, anything else -> 0
			bool onoff = !strcmp("ON", arg);
			// process directive
			if (DIR_HANGUP == key) {
				// turn SIGHUP on/off
				signal(SIGHUP, onoff ? signal_handler : SIG_IGN);
			} else if (DIR_ABORT == key) {
				// append the string to abort conditions
#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
				size_t len = strlen(arg);
				if (len > max_abort_len)
					max_abort_len = len;
#endif
				llist_add_to_end(&aborts, arg);
#if ENABLE_FEATURE_CHAT_CLR_ABORT
			} else if (DIR_CLR_ABORT == key) {
				// remove the string from abort conditions
				// N.B. gotta refresh maximum length too...
#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
				max_abort_len = 0;
#endif
				for (llist_t *l = aborts; l; l = l->link) {
#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
					size_t len = strlen(l->data);
#endif
					if (!strcmp(arg, l->data)) {
						llist_unlink(&aborts, l);
						continue;
					}
#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
					if (len > max_abort_len)
						max_abort_len = len;
#endif
				}
#endif
			} else if (DIR_TIMEOUT == key) {
				// set new timeout
				// -1 means OFF
				timeout = atoi(arg) * 1000;
				// 0 means default
				// >0 means value in msecs
				if (!timeout)
					timeout = DEFAULT_CHAT_TIMEOUT;
			} else if (DIR_ECHO == key) {
				// turn echo on/off
				// N.B. echo means dumping output
				// from stdin (device) to stderr
				echo = onoff;
//TODO?				echo_fd = onoff * STDERR_FILENO;
//TODO?				echo_fd = xopen(arg, O_WRONLY|O_CREAT|O_TRUNC);
			} else if (DIR_SAY == key) {
				// just print argument verbatim
				fprintf(stderr, arg);
			}
			// next, please!
			argv++;
		// ordinary expect-send pair!
		} else {
			//-----------------------
			// do expect
			//-----------------------
			size_t expect_len, buf_len = 0;
			size_t max_len = max_abort_len;

			struct pollfd pfd;
#if ENABLE_FEATURE_CHAT_NOFAIL
			int nofail = 0;
#endif
			char *expect = *argv++;

			// sanity check: shall we really expect something?
			if (!expect)
				goto expect_done;

#if ENABLE_FEATURE_CHAT_NOFAIL
			// if expect starts with -
			if ('-' == *expect) {
				// swallow -
				expect++;
				// and enter nofail mode
				nofail++;
			}
#endif

#ifdef ___TEST___BUF___ // test behaviour with a small buffer
#	undef COMMON_BUFSIZE
#	define COMMON_BUFSIZE 6
#endif
			// expand escape sequences in expect
			expect_len = unescape(expect, &expect_len /*dummy*/);
			if (expect_len > max_len)
				max_len = expect_len;
			// sanity check:
			// we should expect more than nothing but not more than input buffer
			// TODO: later we'll get rid of fixed-size buffer
			if (!expect_len)
				goto expect_done;
			if (max_len >= COMMON_BUFSIZE) {
				exitcode = ERR_MEM;
				goto expect_done;
			}

			// get reply
			pfd.fd = STDIN_FILENO;
			pfd.events = POLLIN;
			while (!exitcode
			    && poll(&pfd, 1, timeout) > 0
			    && (pfd.revents & POLLIN)
			) {
#define buf bb_common_bufsiz1
				llist_t *l;
				ssize_t delta;

				// read next char from device
				if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) {
					// dump device output if ECHO ON or RECORD fname
//TODO?					if (echo_fd > 0) {
//TODO?						full_write(echo_fd, buf+buf_len, 1);
//TODO?					}
					if (echo > 0)
						full_write(STDERR_FILENO, buf+buf_len, 1);
					buf_len++;
					// move input frame if we've reached higher bound
					if (buf_len > COMMON_BUFSIZE) {
						memmove(buf, buf+buf_len-max_len, max_len);
						buf_len = max_len;
					}
				}
				// N.B. rule of thumb: values being looked for can
				// be found only at the end of input buffer
				// this allows to get rid of strstr() and memmem()

				// TODO: make expect and abort strings processed uniformly
				// abort condition is met? -> bail out
				for (l = aborts, exitcode = ERR_ABORT; l; l = l->link, ++exitcode) {
					size_t len = strlen(l->data);
					delta = buf_len-len;
					if (delta >= 0 && !memcmp(buf+delta, l->data, len))
						goto expect_done;
				}
				exitcode = ERR_OK;

				// expected reply received? -> goto next command
				delta = buf_len-expect_len;
				if (delta >= 0 && !memcmp(buf+delta, expect, expect_len))
					goto expect_done;
#undef buf
			}

			// device timed out or unexpected reply received
			exitcode = ERR_TIMEOUT;
 expect_done:
#if ENABLE_FEATURE_CHAT_NOFAIL
			// on success and when in nofail mode
			// we should skip following subsend-subexpect pairs
			if (nofail) {
				if (!exitcode) {
					// find last send before non-dashed expect
					while (*argv && argv[1] && '-' == argv[1][0])
						argv += 2;
					// skip the pair
					// N.B. do we really need this?!
					if (!*argv++ || !*argv++)
						break;
				}
				// nofail mode also clears all but IO errors (or signals)
				if (ERR_IO != exitcode)
					exitcode = ERR_OK;
			}
#endif
			// bail out unless we expected successfully
			if (exitcode)
				break;

			//-----------------------
			// do send
			//-----------------------
			if (*argv) {
#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
				int nocr = 0; // inhibit terminating command with \r
#endif
				char *loaded = NULL; // loaded command
				size_t len;
				char *buf = *argv++;

				// if command starts with @
				// load "real" command from file named after @
				if ('@' == *buf) {
					// skip the @ and any following white-space
					trim(++buf);
					buf = loaded = xmalloc_open_read_close(buf, NULL);
				}

				// expand escape sequences in command
				len = unescape(buf, &nocr);

				// send command
#if ENABLE_FEATURE_CHAT_SEND_ESCAPES
				pfd.fd = STDOUT_FILENO;
				pfd.events = POLLOUT;
				while (len && !exitcode
				    && poll(&pfd, 1, timeout) > 0
				    && (pfd.revents & POLLOUT)
				) {
					// ugly! ugly! ugly!
					// gotta send char by char to achieve this!
					// Brrr...
					// "\\d" means 1 sec delay, "\\p" means 0.01 sec delay
					// "\\K" means send BREAK
					char c = *buf;
					if ('\\' == c) {
						c = *++buf;
						if ('d' == c) {
							sleep(1);
							len--;
							continue;
						} else if ('p' == c) {
							usleep(10000);
							len--;
							continue;
						} else if ('K' == c) {
							tcsendbreak(STDOUT_FILENO, 0);
							len--;
							continue;
						} else {
							buf--;
						}
					}
					if (safe_write(STDOUT_FILENO, buf, 1) > 0) {
						len--;
						buf++;
					} else
						break;
				}
#else
//				if (len) {
					alarm(timeout);
					len -= full_write(STDOUT_FILENO, buf, len);
					alarm(0);
//				}
#endif

				// report I/O error if there still exists at least one non-sent char
				if (len)
					exitcode = ERR_IO;

				// free loaded command (if any)
				if (loaded)
					free(loaded);
#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
				// or terminate command with \r (if not inhibited)
				else if (!nocr)
					xwrite(STDOUT_FILENO, "\r", 1);
#endif

				// bail out unless we sent command successfully
				if (exitcode)
					break;

			}
		}
	}

#if ENABLE_FEATURE_CHAT_TTY_HIFI
	tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
#endif

	return exitcode;
}