summaryrefslogtreecommitdiffstats
path: root/term-utils/wall.c
blob: c601d3e5b73582dfaa20edf04b2a61e8384a7f1f (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
444
445
446
447
448
449
450
/*
 * Copyright (c) 1988, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Modified Sun Mar 12 10:34:34 1995, faith@cs.unc.edu, for Linux
 */

/*
 * This program is not related to David Wall, whose Stanford Ph.D. thesis
 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
 *
 * 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
 * - added Native Language Support
 *
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>

#include <errno.h>
#include <paths.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include <getopt.h>
#include <sys/types.h>
#include <grp.h>

#include "nls.h"
#include "xalloc.h"
#include "strutils.h"
#include "ttymsg.h"
#include "pathnames.h"
#include "carefulputc.h"
#include "c.h"
#include "cctype.h"
#include "fileutils.h"
#include "closestream.h"
#include "timeutils.h"
#include "pwdutils.h"

#define	TERM_WIDTH	79
#define	WRITE_TIME_OUT	300		/* in seconds */

/* Function prototypes */
static char *makemsg(char *fname, char **mvec, int mvecsz,
		    size_t *mbufsize, int print_banner);

static void __attribute__((__noreturn__)) usage(void)
{
	FILE *out = stdout;
	fputs(USAGE_HEADER, out);
	fprintf(out,
	      _(" %s [options] [<file> | <message>]\n"), program_invocation_short_name);

	fputs(USAGE_SEPARATOR, out);
	fputs(_("Write a message to all users.\n"), out);

	fputs(USAGE_OPTIONS, out);
	fputs(_(" -g, --group <group>     only send message to group\n"), out);
	fputs(_(" -n, --nobanner          do not print banner, works only for root\n"), out);
	fputs(_(" -t, --timeout <timeout> write timeout in seconds\n"), out);
	fputs(USAGE_SEPARATOR, out);
	printf(USAGE_HELP_OPTIONS(25));
	printf(USAGE_MAN_TAIL("wall(1)"));

	exit(EXIT_SUCCESS);
}

struct group_workspace {
	gid_t	requested_group;
	int	ngroups;

/* getgrouplist() on OSX takes int* not gid_t* */
#ifdef __APPLE__
	int	*groups;
#else
	gid_t	*groups;
#endif
};

static gid_t get_group_gid(const char *group)
{
	struct group *gr;
	gid_t gid;

	if ((gr = getgrnam(group)))
		return gr->gr_gid;

	gid = strtou32_or_err(group, _("invalid group argument"));
	if (!getgrgid(gid))
		errx(EXIT_FAILURE, _("%s: unknown gid"), group);

	return gid;
}

static struct group_workspace *init_group_workspace(const char *group)
{
	struct group_workspace *buf = xmalloc(sizeof(struct group_workspace));

	buf->requested_group = get_group_gid(group);
	buf->ngroups = sysconf(_SC_NGROUPS_MAX) + 1;  /* room for the primary gid */
	buf->groups = xcalloc(sizeof(*buf->groups), buf->ngroups);

	return buf;
}

static void free_group_workspace(struct group_workspace *buf)
{
	if (!buf)
		return;

	free(buf->groups);
	free(buf);
}

static int is_gr_member(const char *login, const struct group_workspace *buf)
{
	struct passwd *pw;
	int ngroups = buf->ngroups;
	int rc;

	pw = getpwnam(login);
	if (!pw)
		return 0;

	if (buf->requested_group == pw->pw_gid)
		return 1;

	rc = getgrouplist(login, pw->pw_gid, buf->groups, &ngroups);
	if (rc < 0) {
		/* buffer too small, not sure how this can happen, since
		   we used sysconf to get the size... */
		errx(EXIT_FAILURE,
			_("getgrouplist found more groups than sysconf allows"));
	}

	for (; ngroups >= 0; --ngroups) {
		if (buf->requested_group == (gid_t) buf->groups[ngroups])
			return 1;
	}

	return 0;
}

int main(int argc, char **argv)
{
	int ch;
	struct iovec iov;
	struct utmpx *utmpptr;
	char *p;
	char line[sizeof(utmpptr->ut_line) + 1];
	int print_banner = TRUE;
	struct group_workspace *group_buf = NULL;
	char *mbuf, *fname = NULL;
	size_t mbufsize;
	unsigned timeout = WRITE_TIME_OUT;
	char **mvec = NULL;
	int mvecsz = 0;

	static const struct option longopts[] = {
		{ "nobanner",	no_argument,		NULL, 'n' },
		{ "timeout",	required_argument,	NULL, 't' },
		{ "group",	required_argument,	NULL, 'g' },
		{ "version",	no_argument,		NULL, 'V' },
		{ "help",	no_argument,		NULL, 'h' },
		{ NULL,	0, NULL, 0 }
	};

	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);
	close_stdout_atexit();

	while ((ch = getopt_long(argc, argv, "nt:g:Vh", longopts, NULL)) != -1) {
		switch (ch) {
		case 'n':
			if (geteuid() == 0)
				print_banner = FALSE;
			else
				warnx(_("--nobanner is available only for root"));
			break;
		case 't':
			timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
			if (timeout < 1)
				errx(EXIT_FAILURE, _("invalid timeout argument: %s"), optarg);
			break;
		case 'g':
			group_buf = init_group_workspace(optarg);
			break;

		case 'V':
			print_version(EXIT_SUCCESS);
		case 'h':
			usage();
		default:
			errtryhelp(EXIT_FAILURE);
		}
	}
	argc -= optind;
	argv += optind;

	if (argc == 1 && access(argv[0], F_OK) == 0)
		fname = argv[0];
	else if (argc >= 1) {
		mvec = argv;
		mvecsz = argc;
	}

	mbuf = makemsg(fname, mvec, mvecsz, &mbufsize, print_banner);

	iov.iov_base = mbuf;
	iov.iov_len = mbufsize;
	while((utmpptr = getutxent())) {
		if (!utmpptr->ut_user[0])
			continue;
#ifdef USER_PROCESS
		if (utmpptr->ut_type != USER_PROCESS)
			continue;
#endif
		/* Joey Hess reports that use-sessreg in /etc/X11/wdm/ produces
		 * ut_line entries like :0, and a write to /dev/:0 fails.
		 *
		 * It also seems that some login manager may produce empty ut_line.
		 */
		if (!*utmpptr->ut_line || *utmpptr->ut_line == ':')
			continue;

		if (group_buf && !is_gr_member(utmpptr->ut_user, group_buf))
			continue;

		mem2strcpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line), sizeof(line));
		if ((p = ttymsg(&iov, 1, line, timeout)) != NULL)
			warnx("%s", p);
	}
	endutxent();
	free(mbuf);
	free_group_workspace(group_buf);
	exit(EXIT_SUCCESS);
}

struct buffer {
	size_t	sz;
	size_t	used;
	char	*data;
};

static void buf_enlarge(struct buffer *bs, size_t len)
{
	if (bs->sz == 0 || len > bs->sz - bs->used) {
		bs->sz += len < 128 ? 128 : len;
		bs->data = xrealloc(bs->data, bs->sz);
	}
}

static void buf_puts(struct buffer *bs, const char *s)
{
	size_t len = strlen(s);

	buf_enlarge(bs, len + 1);
	memcpy(bs->data + bs->used, s, len + 1);
	bs->used += len;
}

static void __attribute__((__format__ (__printf__, 2, 3)))
	buf_printf(struct buffer *bs, const char *fmt, ...)
{
	int rc;
	va_list ap;
	size_t limit;

	buf_enlarge(bs, 0);	/* default size */
	limit = bs->sz - bs->used;

	va_start(ap, fmt);
	rc = vsnprintf(bs->data + bs->used, limit, fmt, ap);
	va_end(ap);

	if (rc >= 0 && (size_t) rc >= limit) {	/* not enough, enlarge */
		buf_enlarge(bs, (size_t)rc + 1);
		limit = bs->sz - bs->used;
		va_start(ap, fmt);
		rc = vsnprintf(bs->data  + bs->used, limit, fmt, ap);
		va_end(ap);
	}

	if (rc > 0)
		bs->used += rc;
}

static void buf_putc_careful(struct buffer *bs, int c)
{
	if (isprint(c) || c == '\a' || c == '\t' || c == '\r' || c == '\n') {
		buf_enlarge(bs, 1);
		bs->data[bs->used++] = c;
	} else if (!c_isascii(c))
		buf_printf(bs, "\\%3o", (unsigned char)c);
	else {
		char tmp[] = { '^', c ^ 0x40, '\0' };
		buf_puts(bs, tmp);
	}
}

static char *makemsg(char *fname, char **mvec, int mvecsz,
		     size_t *mbufsize, int print_banner)
{
	struct buffer _bs = {.used = 0}, *bs = &_bs;
	register int ch, cnt;
	char *p, *lbuf;
	long line_max;

	line_max = sysconf(_SC_LINE_MAX);
	if (line_max <= 0)
		line_max = 512;

	lbuf = xmalloc(line_max);

	if (print_banner == TRUE) {
		char *hostname = xgethostname();
		char *whom, *where, date[CTIME_BUFSIZ];
		time_t now;

		whom = xgetlogin();
		if (!whom) {
			whom = "<someone>";
			warn(_("cannot get passwd uid"));
		}
		where = ttyname(STDOUT_FILENO);
		if (!where) {
			where = "somewhere";
		} else if (strncmp(where, "/dev/", 5) == 0)
			where += 5;

		time(&now);
		ctime_r(&now, date);
		date[strlen(date) - 1] = '\0';

		/*
		 * all this stuff is to blank out a square for the message;
		 * we wrap message lines at column 79, not 80, because some
		 * terminals wrap after 79, some do not, and we can't tell.
		 * Which means that we may leave a non-blank character
		 * in column 80, but that can't be helped.
		 */
		/* snprintf is not always available, but the sprintf's here
		   will not overflow as long as %d takes at most 100 chars */
		buf_printf(bs, "\r%*s\r\n", TERM_WIDTH, " ");

		snprintf(lbuf, line_max,
				_("Broadcast message from %s@%s (%s) (%s):"),
				whom, hostname, where, date);
		buf_printf(bs, "%-*.*s\007\007\r\n", TERM_WIDTH, TERM_WIDTH, lbuf);
		free(hostname);
	}
	buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");

	 if (mvec) {
		/*
		 * Read message from argv[]
		 */
		int i;

		for (i = 0; i < mvecsz; i++) {
			buf_puts(bs, mvec[i]);
			if (i < mvecsz - 1)
				buf_puts(bs, " ");
		}
		buf_puts(bs, "\r\n");
	} else {
		/*
		 * read message from <file>
		 */
		if (fname) {
			/*
			 * When we are not root, but suid or sgid, refuse to read files
			 * (e.g. device files) that the user may not have access to.
			 * After all, our invoker can easily do "wall < file"
			 * instead of "wall file".
			 */
			uid_t uid = getuid();
			if (uid && (uid != geteuid() || getgid() != getegid()))
				errx(EXIT_FAILURE, _("will not read %s - use stdin."),
				     fname);

			if (!freopen(fname, "r", stdin))
				err(EXIT_FAILURE, _("cannot open %s"), fname);

		}

		/*
		 * Read message from stdin.
		 */
		while (fgets(lbuf, line_max, stdin)) {
			for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
				if (cnt == TERM_WIDTH || ch == '\n') {
					for (; cnt < TERM_WIDTH; ++cnt)
						buf_puts(bs, " ");
					buf_puts(bs, "\r\n");
					cnt = 0;
				}
				if (ch == '\t')
					cnt += (7 - (cnt % 8));
				if (ch != '\n')
					buf_putc_careful(bs, ch);
			}
		}
	}
	buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");

	free(lbuf);

	bs->data[bs->used] = '\0';	/* be paranoid */
	*mbufsize = bs->used;
	return bs->data;
}