xref: /freebsd/usr.bin/who/who.c (revision 43a5ec4eb41567cc92586503212743d89686d78f)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Tim J. Robbins.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/ioctl.h>
35 #include <sys/stat.h>
36 
37 #include <err.h>
38 #include <errno.h>
39 #include <langinfo.h>
40 #include <limits.h>
41 #include <locale.h>
42 #include <paths.h>
43 #include <pwd.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <time.h>
48 #include <timeconv.h>
49 #include <unistd.h>
50 #include <utmpx.h>
51 
52 static void	heading(void);
53 static void	process_utmp(void);
54 static void	quick(void);
55 static void	row(const struct utmpx *);
56 static int	ttywidth(void);
57 static void	usage(void);
58 static void	whoami(void);
59 
60 static int	Hflag;			/* Write column headings */
61 static int	aflag;			/* Print all entries */
62 static int	bflag;			/* Show date of the last reboot */
63 static int	mflag;			/* Show info about current terminal */
64 static int	qflag;			/* "Quick" mode */
65 static int	sflag;			/* Show name, line, time */
66 static int	Tflag;			/* Show terminal state */
67 static int	uflag;			/* Show idle time */
68 
69 int
70 main(int argc, char *argv[])
71 {
72 	int ch;
73 
74 	setlocale(LC_TIME, "");
75 
76 	while ((ch = getopt(argc, argv, "HTabmqsu")) != -1) {
77 		switch (ch) {
78 		case 'H':		/* Write column headings */
79 			Hflag = 1;
80 			break;
81 		case 'T':		/* Show terminal state */
82 			Tflag = 1;
83 			break;
84 		case 'a':		/* Same as -bdlprtTu */
85 			aflag = bflag = Tflag = uflag = 1;
86 			break;
87 		case 'b':		/* Show date of the last reboot */
88 			bflag = 1;
89 			break;
90 		case 'm':		/* Show info about current terminal */
91 			mflag = 1;
92 			break;
93 		case 'q':		/* "Quick" mode */
94 			qflag = 1;
95 			break;
96 		case 's':		/* Show name, line, time */
97 			sflag = 1;
98 			break;
99 		case 'u':		/* Show idle time */
100 			uflag = 1;
101 			break;
102 		default:
103 			usage();
104 			/*NOTREACHED*/
105 		}
106 	}
107 	argc -= optind;
108 	argv += optind;
109 
110 	if (argc >= 2 && strcmp(argv[0], "am") == 0 &&
111 	    (strcmp(argv[1], "i") == 0 || strcmp(argv[1], "I") == 0)) {
112 		/* "who am i" or "who am I", equivalent to -m */
113 		mflag = 1;
114 		argc -= 2;
115 		argv += 2;
116 	}
117 	if (argc > 1)
118 		usage();
119 
120 	if (*argv != NULL) {
121 		if (setutxdb(UTXDB_ACTIVE, *argv) != 0)
122 			err(1, "%s", *argv);
123 	}
124 
125 	if (qflag)
126 		quick();
127 	else {
128 		if (sflag)
129 			Tflag = uflag = 0;
130 		if (Hflag)
131 			heading();
132 		if (mflag)
133 			whoami();
134 		else
135 			process_utmp();
136 	}
137 
138 	endutxent();
139 
140 	exit(0);
141 }
142 
143 static void
144 usage(void)
145 {
146 
147 	fprintf(stderr, "usage: who [-abHmqsTu] [am I] [file]\n");
148 	exit(1);
149 }
150 
151 static void
152 heading(void)
153 {
154 
155 	printf("%-16s ", "NAME");
156 	if (Tflag)
157 		printf("S ");
158 	printf("%-12s %-12s ", "LINE", "TIME");
159 	if (uflag)
160 		printf("IDLE  ");
161 	printf("%-16s\n", "FROM");
162 }
163 
164 static void
165 row(const struct utmpx *ut)
166 {
167 	char buf[80], tty[PATH_MAX];
168 	struct stat sb;
169 	time_t idle, t;
170 	static int d_first = -1;
171 	struct tm *tm;
172 	char state;
173 
174 	if (d_first < 0)
175 		d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
176 
177 	state = '?';
178 	idle = 0;
179 	if (Tflag || uflag) {
180 		snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, ut->ut_line);
181 		if (stat(tty, &sb) == 0) {
182 			state = sb.st_mode & (S_IWOTH|S_IWGRP) ?
183 			    '+' : '-';
184 			idle = time(NULL) - sb.st_mtime;
185 		}
186 	}
187 
188 	printf("%-16s ", ut->ut_user);
189 	if (Tflag)
190 		printf("%c ", state);
191 	if (ut->ut_type == BOOT_TIME)
192 		printf("%-12s ", "system boot");
193 	else
194 		printf("%-12s ", ut->ut_line);
195 	t = ut->ut_tv.tv_sec;
196 	tm = localtime(&t);
197 	strftime(buf, sizeof(buf), d_first ? "%e %b %R" : "%b %e %R", tm);
198 	printf("%-*s ", 12, buf);
199 	if (uflag) {
200 		if (idle < 60)
201 			printf("  .   ");
202 		else if (idle < 24 * 60 * 60)
203 			printf("%02d:%02d ", (int)(idle / 60 / 60),
204 			    (int)(idle / 60 % 60));
205 		else
206 			printf(" old  ");
207 	}
208 	if (*ut->ut_host != '\0')
209 		printf("(%s)", ut->ut_host);
210 	putchar('\n');
211 }
212 
213 static int
214 ttystat(char *line)
215 {
216 	struct stat sb;
217 	char ttybuf[MAXPATHLEN];
218 
219 	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
220 	if (stat(ttybuf, &sb) == 0) {
221 		return (0);
222 	} else
223 		return (-1);
224 }
225 
226 static void
227 process_utmp(void)
228 {
229 	struct utmpx *utx;
230 
231 	while ((utx = getutxent()) != NULL) {
232 		if (((aflag || !bflag) && utx->ut_type == USER_PROCESS) ||
233 		    (bflag && utx->ut_type == BOOT_TIME))
234 			if (ttystat(utx->ut_line) == 0)
235 				row(utx);
236 	}
237 }
238 
239 static void
240 quick(void)
241 {
242 	struct utmpx *utx;
243 	int col, ncols, num;
244 
245 	ncols = ttywidth();
246 	col = num = 0;
247 	while ((utx = getutxent()) != NULL) {
248 		if (utx->ut_type != USER_PROCESS)
249 			continue;
250 		printf("%-16s", utx->ut_user);
251 		if (++col < ncols / (16 + 1))
252 			putchar(' ');
253 		else {
254 			col = 0;
255 			putchar('\n');
256 		}
257 		num++;
258 	}
259 	if (col != 0)
260 		putchar('\n');
261 
262 	printf("# users = %d\n", num);
263 }
264 
265 static void
266 whoami(void)
267 {
268 	struct utmpx ut, *utx;
269 	struct passwd *pwd;
270 	const char *name, *tty;
271 
272 	if ((tty = ttyname(STDIN_FILENO)) == NULL)
273 		tty = "tty??";
274 	else if (strncmp(tty, _PATH_DEV, sizeof _PATH_DEV - 1) == 0)
275 		tty += sizeof _PATH_DEV - 1;
276 	strlcpy(ut.ut_line, tty, sizeof ut.ut_line);
277 
278 	/* Search utmp for our tty, dump first matching record. */
279 	if ((utx = getutxline(&ut)) != NULL && utx->ut_type == USER_PROCESS) {
280 		row(utx);
281 		return;
282 	}
283 
284 	/* Not found; fill the utmp structure with the information we have. */
285 	memset(&ut, 0, sizeof(ut));
286 	if ((pwd = getpwuid(getuid())) != NULL)
287 		name = pwd->pw_name;
288 	else
289 		name = "?";
290 	strlcpy(ut.ut_user, name, sizeof ut.ut_user);
291 	gettimeofday(&ut.ut_tv, NULL);
292 	row(&ut);
293 }
294 
295 static int
296 ttywidth(void)
297 {
298 	struct winsize ws;
299 	long width;
300 	char *cols, *ep;
301 
302 	if ((cols = getenv("COLUMNS")) != NULL && *cols != '\0') {
303 		errno = 0;
304 		width = strtol(cols, &ep, 10);
305 		if (errno || width <= 0 || width > INT_MAX || ep == cols ||
306 		    *ep != '\0')
307 			warnx("invalid COLUMNS environment variable ignored");
308 		else
309 			return (width);
310 	}
311 	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1)
312 		return (ws.ws_col);
313 
314 	return (80);
315 }
316