usr.bin/who/who.c

   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  * $FreeBSD: src/usr.bin/who/who.c,v 1.9.2.4 2002/12/21 00:44:58 tjr Exp $
  27  * $DragonFly: src/usr.bin/who/who.c,v 1.7 2008/06/05 18:06:33 swildner Exp $
  28  */
  29
  30 #include <sys/types.h>
  31 #include <sys/ioctl.h>
  32 #include <sys/stat.h>
  33 #include <sys/sysctl.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 <unistd.h>
  47 #include <utmp.h>
  48
  49 static void     print_boottime(void);
  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      bflag;                  /* Show date and time of last reboot */
  59 static int      Hflag;                  /* Write column headings */
  60 static int      mflag;                  /* Show info about current terminal */
  61 static int      qflag;                  /* "Quick" mode */
  62 static int      sflag;                  /* Show name, line, time */
  63 static int      Tflag;                  /* Show terminal state */
  64 static int      uflag;                  /* Show idle time */
  65
  66 int
  67 main(int argc, char **argv)
  68 {
  69         int ch;
  70         const char *file;
  71         FILE *fp;
  72
  73         setlocale(LC_TIME, "");
  74
  75         while ((ch = getopt(argc, argv, "HTbmqsu")) != -1) {
  76                 switch (ch) {
  77                 case 'H':               /* Write column headings */
  78                         Hflag = 1;
  79                         break;
  80                 case 'T':               /* Show terminal state */
  81                         Tflag = 1;
  82                         break;
  83                 case 'b':               /* Show time and date since last boot */
  84                         bflag = 1;
  85                         break;
  86                 case 'm':               /* Show info about current terminal */
  87                         mflag = 1;
  88                         break;
  89                 case 'q':               /* "Quick" mode */
  90                         qflag = 1;
  91                         break;
  92                 case 's':               /* Show name, line, time */
  93                         sflag = 1;
  94                         break;
  95                 case 'u':               /* Show idle time */
  96                         uflag = 1;
  97                         break;
  98                 default:
  99                         usage();
 100                         /*NOTREACHED*/
 101                 }
 102         }
 103         argc -= optind;
 104         argv += optind;
 105
 106         if (argc >= 2 && strcmp(argv[0], "am") == 0 &&
 107             strcasecmp(argv[1], "i") == 0) {
 108                 /* "who am i" or "who am I", equivalent to -m */
 109                 mflag = 1;
 110                 argc -= 2;
 111                 argv += 2;
 112         }
 113         if (argc > 1)
 114                 usage();
 115
 116         if (*argv != NULL)
 117                 file = *argv;
 118         else
 119                 file = _PATH_UTMP;
 120         if ((fp = fopen(file, "r")) == NULL)
 121                 err(1, "%s", file);
 122
 123         if (qflag)
 124                 quick(fp);
 125         else {
 126                 if (sflag)
 127                         Tflag = uflag = 0;
 128                 if (bflag)
 129                         print_boottime();
 130                 if (Hflag)
 131                         heading();
 132                 if (mflag)
 133                         whoami(fp);
 134                 else
 135                         process_utmp(fp);
 136         }
 137
 138         fclose(fp);
 139
 140         exit(0);
 141 }
 142
 143 static void
 144 usage(void)
 145 {
 146         fprintf(stderr, "usage: who [-bHmqsTu] [am I] [file]\n");
 147         exit(1);
 148 }
 149
 150 static void
 151 print_boottime(void)
 152 {
 153         struct timeval boottime;
 154         size_t size;
 155
 156         size = sizeof(boottime);
 157         if (sysctlbyname("kern.boottime", &boottime, &size, NULL, 0) != -1 &&
 158             boottime.tv_sec != 0) {
 159                 printf("%s", ctime(&boottime.tv_sec));
 160         }
 161 }
 162
 163 static void
 164 heading(void)
 165 {
 166         printf("%-*s ", UT_NAMESIZE, "NAME");
 167         if (Tflag)
 168                 printf("S ");
 169         printf("%-*s ", UT_LINESIZE, "LINE");
 170         printf("%-*s ", 12, "TIME");
 171         if (uflag)
 172                 printf("IDLE  ");
 173         printf("%-*s", UT_HOSTSIZE, "FROM");
 174         putchar('\n');
 175 }
 176
 177 static void
 178 row(struct utmp *ut)
 179 {
 180         char buf[80], tty[sizeof(_PATH_DEV) + UT_LINESIZE];
 181         struct stat sb;
 182         time_t idle = 0;
 183         static int d_first = -1;
 184         struct tm *tm;
 185         char state = '?';
 186
 187         if (d_first < 0)
 188                 d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
 189
 190         if (Tflag || uflag) {
 191                 snprintf(tty, sizeof(tty), "%s%.*s", _PATH_DEV,
 192                         UT_LINESIZE, ut->ut_line);
 193                 if (stat(tty, &sb) == 0) {
 194                         state = sb.st_mode & (S_IWOTH|S_IWGRP) ?
 195                             '+' : '-';
 196                         idle = time(NULL) - sb.st_mtime;
 197                 } else {
 198                         err(1, "Cannot open %s", tty);
 199                 }
 200         }
 201
 202         printf("%-*.*s ", UT_NAMESIZE, UT_NAMESIZE, ut->ut_name);
 203         if (Tflag)
 204                 printf("%c ", state);
 205         printf("%-*.*s ", UT_LINESIZE, UT_LINESIZE, ut->ut_line);
 206         tm = localtime(&ut->ut_time);
 207         strftime(buf, sizeof(buf), d_first ? "%e %b %R" : "%b %e %R", tm);
 208         printf("%-*s ", 12, buf);
 209         if (uflag) {
 210                 if (idle < 60)
 211                         printf("  .   ");
 212                 else if (idle < 24 * 60 * 60)
 213                         printf("%02d:%02d ", (int)(idle / 60 / 60),
 214                             (int)(idle / 60 % 60));
 215                 else
 216                         printf(" old  ");
 217         }
 218         if (*ut->ut_host != '\0')
 219                 printf("(%.*s)", UT_HOSTSIZE, ut->ut_host);
 220         putchar('\n');
 221 }
 222
 223 static void
 224 process_utmp(FILE *fp)
 225 {
 226         struct utmp ut;
 227
 228         while (fread(&ut, sizeof(ut), 1, fp) == 1)
 229                 if (*ut.ut_name != '\0')
 230                         row(&ut);
 231 }
 232
 233 static void
 234 quick(FILE *fp)
 235 {
 236         struct utmp ut;
 237         int col, ncols, num;
 238
 239         ncols = ttywidth();
 240         col = num = 0;
 241         while (fread(&ut, sizeof(ut), 1, fp) == 1) {
 242                 if (*ut.ut_name == '\0')
 243                         continue;
 244                 printf("%-*.*s", UT_NAMESIZE, UT_NAMESIZE, ut.ut_name);
 245                 if (++col < ncols / (UT_NAMESIZE + 1))
 246                         putchar(' ');
 247                 else {
 248                         col = 0;
 249                         putchar('\n');
 250                 }
 251                 num++;
 252         }
 253         if (col != 0)
 254                 putchar('\n');
 255
 256         printf("# users = %d\n", num);
 257 }
 258
 259 static void
 260 whoami(FILE *fp)
 261 {
 262         struct utmp ut;
 263         struct passwd *pwd;
 264         const char *name, *p, *tty;
 265
 266         if ((tty = ttyname(STDIN_FILENO)) == NULL)
 267                 tty = "tty??";
 268         else if ((p = strrchr(tty, '/')) != NULL)
 269                 tty = p + 1;
 270
 271         /* Search utmp for our tty, dump first matching record. */
 272         while (fread(&ut, sizeof(ut), 1, fp) == 1)
 273                 if (*ut.ut_name != '\0' && strncmp(ut.ut_line, tty,
 274                     UT_LINESIZE) == 0) {
 275                         row(&ut);
 276                         return;
 277                 }
 278
 279         /* Not found; fill the utmp structure with the information we have. */
 280         memset(&ut, 0, sizeof(ut));
 281         if ((pwd = getpwuid(getuid())) != NULL)
 282                 name = pwd->pw_name;
 283         else
 284                 name = "?";
 285         strncpy(ut.ut_name, name, UT_NAMESIZE);
 286         strncpy(ut.ut_line, tty, UT_LINESIZE);
 287         time(&ut.ut_time);
 288         row(&ut);
 289 }
 290
 291 static int
 292 ttywidth(void)
 293 {
 294         struct winsize ws;
 295         long width;
 296         char *cols, *ep;
 297
 298         if ((cols = getenv("COLUMNS")) != NULL && *cols != '\0') {
 299                 errno = 0;
 300                 width = strtol(cols, &ep, 10);
 301                 if (errno || width <= 0 || width > INT_MAX || ep == cols ||
 302                     *ep != '\0')
 303                         warnx("invalid COLUMNS environment variable ignored");
 304                 else
 305                         return (width);
 306         }
 307         if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1)
 308                 return (ws.ws_col);
 309
 310         return (80);
 311 }