xref: /freebsd/usr.bin/who/who.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /*-
2  * Copyright (c) 2002 Tim J. Robbins.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/types.h>
32 #include <sys/ioctl.h>
33 #include <sys/stat.h>
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <langinfo.h>
38 #include <limits.h>
39 #include <locale.h>
40 #include <paths.h>
41 #include <pwd.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <time.h>
46 #include <timeconv.h>
47 #include <unistd.h>
48 #include <utmp.h>
49 
50 static void	heading(void);
51 static void	process_utmp(FILE *);
52 static void	quick(FILE *);
53 static void	row(struct utmp *);
54 static int	ttywidth(void);
55 static void	usage(void);
56 static void	whoami(FILE *);
57 
58 static int	Hflag;			/* Write column headings */
59 static int	mflag;			/* Show info about current terminal */
60 static int	qflag;			/* "Quick" mode */
61 static int	sflag;			/* Show name, line, time */
62 static int	Tflag;			/* Show terminal state */
63 static int	uflag;			/* Show idle time */
64 
65 int
66 main(int argc, char *argv[])
67 {
68 	int ch;
69 	const char *file;
70 	FILE *fp;
71 
72 	setlocale(LC_TIME, "");
73 
74 	while ((ch = getopt(argc, argv, "HTmqsu")) != -1) {
75 		switch (ch) {
76 		case 'H':		/* Write column headings */
77 			Hflag = 1;
78 			break;
79 		case 'T':		/* Show terminal state */
80 			Tflag = 1;
81 			break;
82 		case 'm':		/* Show info about current terminal */
83 			mflag = 1;
84 			break;
85 		case 'q':		/* "Quick" mode */
86 			qflag = 1;
87 			break;
88 		case 's':		/* Show name, line, time */
89 			sflag = 1;
90 			break;
91 		case 'u':		/* Show idle time */
92 			uflag = 1;
93 			break;
94 		default:
95 			usage();
96 			/*NOTREACHED*/
97 		}
98 	}
99 	argc -= optind;
100 	argv += optind;
101 
102 	if (argc >= 2 && strcmp(argv[0], "am") == 0 &&
103 	    (strcmp(argv[1], "i") == 0 || strcmp(argv[1], "I") == 0)) {
104 		/* "who am i" or "who am I", equivalent to -m */
105 		mflag = 1;
106 		argc -= 2;
107 		argv += 2;
108 	}
109 	if (argc > 1)
110 		usage();
111 
112 	if (*argv != NULL)
113 		file = *argv;
114 	else
115 		file = _PATH_UTMP;
116 	if ((fp = fopen(file, "r")) == NULL)
117 		err(1, "%s", file);
118 
119 	if (qflag)
120 		quick(fp);
121 	else {
122 		if (sflag)
123 			Tflag = uflag = 0;
124 		if (Hflag)
125 			heading();
126 		if (mflag)
127 			whoami(fp);
128 		else
129 			process_utmp(fp);
130 	}
131 
132 	fclose(fp);
133 
134 	exit(0);
135 }
136 
137 static void
138 usage(void)
139 {
140 
141 	fprintf(stderr, "usage: who [-HmqsTu] [am I] [file]\n");
142 	exit(1);
143 }
144 
145 static void
146 heading(void)
147 {
148 
149 	printf("%-*s ", UT_NAMESIZE, "NAME");
150 	if (Tflag)
151 		printf("S ");
152 	printf("%-*s ", UT_LINESIZE, "LINE");
153 	printf("%-*s ", 12, "TIME");
154 	if (uflag)
155 		printf("IDLE  ");
156 	printf("%-*s", UT_HOSTSIZE, "FROM");
157 	putchar('\n');
158 }
159 
160 static void
161 row(struct utmp *ut)
162 {
163 	char buf[80], tty[sizeof(_PATH_DEV) + UT_LINESIZE];
164 	struct stat sb;
165 	time_t idle, t;
166 	static int d_first = -1;
167 	struct tm *tm;
168 	char state;
169 
170 	if (d_first < 0)
171 		d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
172 
173 	state = '?';
174 	idle = 0;
175 	if (Tflag || uflag) {
176 		snprintf(tty, sizeof(tty), "%s%.*s", _PATH_DEV,
177 			UT_LINESIZE, ut->ut_line);
178 		if (stat(tty, &sb) == 0) {
179 			state = sb.st_mode & (S_IWOTH|S_IWGRP) ?
180 			    '+' : '-';
181 			idle = time(NULL) - sb.st_mtime;
182 		}
183 	}
184 
185 	printf("%-*.*s ", UT_NAMESIZE, UT_NAMESIZE, ut->ut_name);
186 	if (Tflag)
187 		printf("%c ", state);
188 	printf("%-*.*s ", UT_LINESIZE, UT_LINESIZE, ut->ut_line);
189 	t = _time32_to_time(ut->ut_time);
190 	tm = localtime(&t);
191 	strftime(buf, sizeof(buf), d_first ? "%e %b %R" : "%b %e %R", tm);
192 	printf("%-*s ", 12, buf);
193 	if (uflag) {
194 		if (idle < 60)
195 			printf("  .   ");
196 		else if (idle < 24 * 60 * 60)
197 			printf("%02d:%02d ", (int)(idle / 60 / 60),
198 			    (int)(idle / 60 % 60));
199 		else
200 			printf(" old  ");
201 	}
202 	if (*ut->ut_host != '\0')
203 		printf("(%.*s)", UT_HOSTSIZE, ut->ut_host);
204 	putchar('\n');
205 }
206 
207 static int
208 ttystat(char *line, int sz)
209 {
210 	struct stat sb;
211 	char ttybuf[MAXPATHLEN];
212 
213 	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%.*s", _PATH_DEV, sz, line);
214 	if (stat(ttybuf, &sb) == 0) {
215 		return (0);
216 	} else
217 		return (-1);
218 }
219 
220 static void
221 process_utmp(FILE *fp)
222 {
223 	struct utmp ut;
224 
225 	while (fread(&ut, sizeof(ut), 1, fp) == 1) {
226 		if (*ut.ut_name == '\0')
227 			continue;
228 		if (ttystat(ut.ut_line, UT_LINESIZE) != 0)
229 			continue;
230 		row(&ut);
231 	}
232 }
233 
234 static void
235 quick(FILE *fp)
236 {
237 	struct utmp ut;
238 	int col, ncols, num;
239 
240 	ncols = ttywidth();
241 	col = num = 0;
242 	while (fread(&ut, sizeof(ut), 1, fp) == 1) {
243 		if (*ut.ut_name == '\0')
244 			continue;
245 		printf("%-*.*s", UT_NAMESIZE, UT_NAMESIZE, ut.ut_name);
246 		if (++col < ncols / (UT_NAMESIZE + 1))
247 			putchar(' ');
248 		else {
249 			col = 0;
250 			putchar('\n');
251 		}
252 		num++;
253 	}
254 	if (col != 0)
255 		putchar('\n');
256 
257 	printf("# users = %d\n", num);
258 }
259 
260 static void
261 whoami(FILE *fp)
262 {
263 	struct utmp ut;
264 	struct passwd *pwd;
265 	const char *name, *p, *tty;
266 
267 	if ((tty = ttyname(STDIN_FILENO)) == NULL)
268 		tty = "tty??";
269 	else if ((p = strrchr(tty, '/')) != NULL)
270 		tty = p + 1;
271 
272 	/* Search utmp for our tty, dump first matching record. */
273 	while (fread(&ut, sizeof(ut), 1, fp) == 1)
274 		if (*ut.ut_name != '\0' && strncmp(ut.ut_line, tty,
275 		    UT_LINESIZE) == 0) {
276 			row(&ut);
277 			return;
278 		}
279 
280 	/* Not found; fill the utmp structure with the information we have. */
281 	memset(&ut, 0, sizeof(ut));
282 	if ((pwd = getpwuid(getuid())) != NULL)
283 		name = pwd->pw_name;
284 	else
285 		name = "?";
286 	strncpy(ut.ut_name, name, UT_NAMESIZE);
287 	strncpy(ut.ut_line, tty, UT_LINESIZE);
288 	ut.ut_time = _time_to_time32(time(NULL));
289 	row(&ut);
290 }
291 
292 static int
293 ttywidth(void)
294 {
295 	struct winsize ws;
296 	long width;
297 	char *cols, *ep;
298 
299 	if ((cols = getenv("COLUMNS")) != NULL && *cols != '\0') {
300 		errno = 0;
301 		width = strtol(cols, &ep, 10);
302 		if (errno || width <= 0 || width > INT_MAX || ep == cols ||
303 		    *ep != '\0')
304 			warnx("invalid COLUMNS environment variable ignored");
305 		else
306 			return (width);
307 	}
308 	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1)
309 		return (ws.ws_col);
310 
311 	return (80);
312 }
313