xref: /freebsd/usr.sbin/watch/watch.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * Copyright (c) 1995 Ugen J.S.Antsilevich
3  *
4  * Redistribution and use in source forms, with and without modification,
5  * are permitted provided that this entire comment appears intact.
6  *
7  * Redistribution in binary form may occur without any restrictions.
8  * Obviously, it would be nice if you gave credit where credit is due
9  * but requiring it would be too onerous.
10  *
11  * This software is provided ``AS IS'' without any warranties of any kind.
12  *
13  * Snoop stuff.
14  */
15 
16 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include <sys/param.h>
20 #include <sys/fcntl.h>
21 #include <sys/filio.h>
22 #include <sys/snoop.h>
23 #include <sys/stat.h>
24 #include <sys/linker.h>
25 #include <sys/module.h>
26 
27 #include <err.h>
28 #include <errno.h>
29 #include <locale.h>
30 #include <paths.h>
31 #include <signal.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <sysexits.h>
36 #include <termcap.h>
37 #include <termios.h>
38 #include <time.h>
39 #include <unistd.h>
40 
41 #define MSG_INIT	"Snoop started."
42 #define MSG_OFLOW	"Snoop stopped due to overflow. Reconnecting."
43 #define MSG_CLOSED	"Snoop stopped due to tty close. Reconnecting."
44 #define MSG_CHANGE	"Snoop device change by user request."
45 #define MSG_NOWRITE	"Snoop device change due to write failure."
46 
47 #define DEV_NAME_LEN	1024	/* for /dev/ttyXX++ */
48 #define MIN_SIZE	256
49 
50 #define CHR_SWITCH	24	/* Ctrl+X	 */
51 #define CHR_CLEAR	23	/* Ctrl+V	 */
52 
53 static void	clear(void);
54 static void	timestamp(const char *);
55 static void	set_tty(void);
56 static void	unset_tty(void);
57 static void	fatal(int, const char *);
58 static int	open_snp(void);
59 static void	cleanup(int);
60 static void	usage(void) __dead2;
61 static void	setup_scr(void);
62 static void	attach_snp(void);
63 static void	detach_snp(void);
64 static void	set_dev(const char *);
65 static void	ask_dev(char *, const char *);
66 
67 int		opt_reconn_close = 0;
68 int		opt_reconn_oflow = 0;
69 int		opt_interactive = 1;
70 int		opt_timestamp = 0;
71 int		opt_write = 0;
72 int		opt_no_switch = 0;
73 const char	*opt_snpdev;
74 
75 char		dev_name[DEV_NAME_LEN];
76 int		snp_io;
77 int		std_in = 0, std_out = 1;
78 
79 int		clear_ok = 0;
80 struct termios	otty;
81 char		tbuf[1024], gbuf[1024];
82 
83 static void
84 clear(void)
85 {
86 
87 	if (clear_ok)
88 		tputs(gbuf, 1, putchar);
89 	fflush(stdout);
90 }
91 
92 static void
93 timestamp(const char *buf)
94 {
95 	time_t		t;
96 	char		btmp[1024];
97 
98 	clear();
99 	printf("\n---------------------------------------------\n");
100 	t = time(NULL);
101 	strftime(btmp, 1024, "Time: %d %b %H:%M", localtime(&t));
102 	printf("%s\n", btmp);
103 	printf("%s\n", buf);
104 	printf("---------------------------------------------\n");
105 	fflush(stdout);
106 }
107 
108 static void
109 set_tty(void)
110 {
111 	struct termios	ntty;
112 
113 	ntty = otty;
114 	ntty.c_lflag &= ~ICANON;	/* disable canonical operation */
115 	ntty.c_lflag &= ~ECHO;
116 #ifdef FLUSHO
117 	ntty.c_lflag &= ~FLUSHO;
118 #endif
119 #ifdef PENDIN
120 	ntty.c_lflag &= ~PENDIN;
121 #endif
122 #ifdef IEXTEN
123 	ntty.c_lflag &= ~IEXTEN;
124 #endif
125 	ntty.c_cc[VMIN] = 1;		/* minimum of one character */
126 	ntty.c_cc[VTIME] = 0;		/* timeout value */
127 
128 	ntty.c_cc[VINTR] = 07;		/* ^G */
129 	ntty.c_cc[VQUIT] = 07;		/* ^G */
130 	tcsetattr(std_in, TCSANOW, &ntty);
131 }
132 
133 static void
134 unset_tty(void)
135 {
136 
137 	tcsetattr(std_in, TCSANOW, &otty);
138 }
139 
140 static void
141 fatal(int error, const char *buf)
142 {
143 
144 	unset_tty();
145 	if (buf)
146 		errx(error, "fatal: %s", buf);
147 	else
148 		exit(error);
149 }
150 
151 static int
152 open_snp(void)
153 {
154 	int		f, mode;
155 
156 	if (opt_write)
157 		mode = O_RDWR;
158 	else
159 		mode = O_RDONLY;
160 
161 	if (opt_snpdev == NULL)
162 		f = open(_PATH_DEV "snp", mode);
163 	else
164 		f = open(opt_snpdev, mode);
165 	if (f == -1)
166 		fatal(EX_OSFILE, "cannot open snoop device");
167 
168 	return (f);
169 }
170 
171 static void
172 cleanup(int signo __unused)
173 {
174 
175 	if (opt_timestamp)
176 		timestamp("Logging Exited.");
177 	close(snp_io);
178 	unset_tty();
179 	exit(EX_OK);
180 }
181 
182 static void
183 usage(void)
184 {
185 
186 	fprintf(stderr, "usage: watch [-ciotnW] [tty name]\n");
187 	exit(EX_USAGE);
188 }
189 
190 static void
191 setup_scr(void)
192 {
193 	char		*cbuf = gbuf, *term;
194 
195 	if (!opt_interactive)
196 		return;
197 	if ((term = getenv("TERM")))
198 		if (tgetent(tbuf, term) == 1)
199 			if (tgetstr("cl", &cbuf))
200 				clear_ok = 1;
201 	set_tty();
202 	clear();
203 }
204 
205 static void
206 detach_snp(void)
207 {
208 	int		fd;
209 
210 	fd = -1;
211 	ioctl(snp_io, SNPSTTY, &fd);
212 }
213 
214 static void
215 attach_snp(void)
216 {
217 	int		snp_tty;
218 
219 	snp_tty = open(dev_name, O_RDONLY | O_NONBLOCK);
220 	if (snp_tty < 0)
221 		fatal(EX_DATAERR, "can't open device");
222 	if (ioctl(snp_io, SNPSTTY, &snp_tty) != 0)
223 		fatal(EX_UNAVAILABLE, "cannot attach to tty");
224 	close(snp_tty);
225 	if (opt_timestamp)
226 		timestamp("Logging Started.");
227 }
228 
229 static void
230 set_dev(const char *name)
231 {
232 	char		buf[DEV_NAME_LEN];
233 	struct stat	sb;
234 
235 	if (strlen(name) > 5 && !strncmp(name, _PATH_DEV, sizeof _PATH_DEV - 1)) {
236 		snprintf(buf, sizeof buf, "%s", name);
237 	} else {
238 		if (strlen(name) == 2)
239 			sprintf(buf, "%s%s", _PATH_TTY, name);
240 		else
241 			sprintf(buf, "%s%s", _PATH_DEV, name);
242 	}
243 
244 	if (*name == '\0' || stat(buf, &sb) < 0)
245 		fatal(EX_DATAERR, "bad device name");
246 
247 	if ((sb.st_mode & S_IFMT) != S_IFCHR)
248 		fatal(EX_DATAERR, "must be a character device");
249 
250 	strlcpy(dev_name, buf, sizeof(dev_name));
251 
252 	attach_snp();
253 }
254 
255 void
256 ask_dev(char *dbuf, const char *msg)
257 {
258 	char		buf[DEV_NAME_LEN];
259 	int		len;
260 
261 	clear();
262 	unset_tty();
263 
264 	if (msg)
265 		printf("%s\n", msg);
266 	if (dbuf)
267 		printf("Enter device name [%s]:", dbuf);
268 	else
269 		printf("Enter device name:");
270 
271 	if (fgets(buf, DEV_NAME_LEN - 1, stdin)) {
272 		len = strlen(buf);
273 		if (buf[len - 1] == '\n')
274 			buf[len - 1] = '\0';
275 		if (buf[0] != '\0' && buf[0] != ' ')
276 			strcpy(dbuf, buf);
277 	}
278 	set_tty();
279 }
280 
281 #define READB_LEN	5
282 
283 int
284 main(int ac, char *av[])
285 {
286 	int		ch, res, rv, nread;
287 	size_t		b_size = MIN_SIZE;
288 	char		*buf, chb[READB_LEN];
289 	fd_set		fd_s;
290 
291 	(void) setlocale(LC_TIME, "");
292 
293 	if (isatty(std_out))
294 		opt_interactive = 1;
295 	else
296 		opt_interactive = 0;
297 
298 	while ((ch = getopt(ac, av, "Wciotnf:")) != -1)
299 		switch (ch) {
300 		case 'W':
301 			opt_write = 1;
302 			break;
303 		case 'c':
304 			opt_reconn_close = 1;
305 			break;
306 		case 'i':
307 			opt_interactive = 1;
308 			break;
309 		case 'o':
310 			opt_reconn_oflow = 1;
311 			break;
312 		case 't':
313 			opt_timestamp = 1;
314 			break;
315 		case 'n':
316 			opt_no_switch = 1;
317 			break;
318 		case 'f':
319 			opt_snpdev = optarg;
320 			break;
321 		case '?':
322 		default:
323 			usage();
324 		}
325 
326 	tcgetattr(std_in, &otty);
327 
328 	if (modfind("snp") == -1)
329 		if (kldload("snp") == -1 || modfind("snp") == -1)
330 			warn("snp module not available");
331 
332 	signal(SIGINT, cleanup);
333 
334 	snp_io = open_snp();
335 	setup_scr();
336 
337 	if (*(av += optind) == NULL) {
338 		if (opt_interactive && !opt_no_switch)
339 			ask_dev(dev_name, MSG_INIT);
340 		else
341 			fatal(EX_DATAERR, "no device name given");
342 	} else
343 		strlcpy(dev_name, *av, sizeof(dev_name));
344 
345 	set_dev(dev_name);
346 
347 	if (!(buf = (char *) malloc(b_size)))
348 		fatal(EX_UNAVAILABLE, "malloc failed");
349 
350 	FD_ZERO(&fd_s);
351 
352 	for (;;) {
353 		if (opt_interactive)
354 			FD_SET(std_in, &fd_s);
355 		FD_SET(snp_io, &fd_s);
356 		res = select(snp_io + 1, &fd_s, NULL, NULL, NULL);
357 		if (opt_interactive && FD_ISSET(std_in, &fd_s)) {
358 
359 			if ((res = ioctl(std_in, FIONREAD, &nread)) != 0)
360 				fatal(EX_OSERR, "ioctl(FIONREAD)");
361 			if (nread > READB_LEN)
362 				nread = READB_LEN;
363 			rv = read(std_in, chb, nread);
364 			if (rv == -1 || rv != nread)
365 				fatal(EX_IOERR, "read (stdin) failed");
366 
367 			switch (chb[0]) {
368 			case CHR_CLEAR:
369 				clear();
370 				break;
371 			case CHR_SWITCH:
372 				if (!opt_no_switch) {
373 					detach_snp();
374 					ask_dev(dev_name, MSG_CHANGE);
375 					set_dev(dev_name);
376 					break;
377 				}
378 			default:
379 				if (opt_write) {
380 					rv = write(snp_io, chb, nread);
381 					if (rv == -1 || rv != nread) {
382 						detach_snp();
383 						if (opt_no_switch)
384 							fatal(EX_IOERR,
385 							    "write failed");
386 						ask_dev(dev_name, MSG_NOWRITE);
387 						set_dev(dev_name);
388 					}
389 				}
390 
391 			}
392 		}
393 		if (!FD_ISSET(snp_io, &fd_s))
394 			continue;
395 
396 		if ((res = ioctl(snp_io, FIONREAD, &nread)) != 0)
397 			fatal(EX_OSERR, "ioctl(FIONREAD)");
398 
399 		switch (nread) {
400 		case SNP_OFLOW:
401 			if (opt_reconn_oflow)
402 				attach_snp();
403 			else if (opt_interactive && !opt_no_switch) {
404 				ask_dev(dev_name, MSG_OFLOW);
405 				set_dev(dev_name);
406 			} else
407 				cleanup(-1);
408 			break;
409 		case SNP_DETACH:
410 		case SNP_TTYCLOSE:
411 			if (opt_reconn_close)
412 				attach_snp();
413 			else if (opt_interactive && !opt_no_switch) {
414 				ask_dev(dev_name, MSG_CLOSED);
415 				set_dev(dev_name);
416 			} else
417 				cleanup(-1);
418 			break;
419 		default:
420 			if (nread < (b_size / 2) && (b_size / 2) > MIN_SIZE) {
421 				free(buf);
422 				if (!(buf = (char *) malloc(b_size / 2)))
423 					fatal(EX_UNAVAILABLE, "malloc failed");
424 				b_size = b_size / 2;
425 			}
426 			if (nread > b_size) {
427 				b_size = (nread % 2) ? (nread + 1) : (nread);
428 				free(buf);
429 				if (!(buf = (char *) malloc(b_size)))
430 					fatal(EX_UNAVAILABLE, "malloc failed");
431 			}
432 			rv = read(snp_io, buf, nread);
433 			if (rv == -1 || rv != nread)
434 				fatal(EX_IOERR, "read failed");
435 			rv = write(std_out, buf, nread);
436 			if (rv == -1 || rv != nread)
437 				fatal(EX_IOERR, "write failed");
438 		}
439 	}			/* While */
440 	return(0);
441 }
442