src/who.c

   1 /* GNU's who.
   2    Copyright (C) 1992-1999 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by jla; revised by djm */
  19
  20 /* Output format:
  21    name [state] line time [idle] host
  22    state: -T
  23    name, line, time: not -q
  24    idle: -u
  25 */
  26
  27 #include <config.h>
  28 #include <getopt.h>
  29 #include <stdio.h>
  30
  31 #include "error.h"
  32 #include "readutmp.h"
  33 #include "system.h"
  34
  35 /* The official name of this program (e.g., no `g' prefix).  */
  36 #define PROGRAM_NAME "who"
  37
  38 #define AUTHORS "Joseph Arceneaux and David MacKenzie"
  39
  40 #ifndef MAXHOSTNAMELEN
  41 # define MAXHOSTNAMELEN 64
  42 #endif
  43
  44 #ifndef S_IWGRP
  45 # define S_IWGRP 020
  46 #endif
  47
  48 int gethostname ();
  49 char *ttyname ();
  50 char *canon_host ();
  51
  52 /* The name this program was run with. */
  53 char *program_name;
  54
  55 /* If nonzero, attempt to canonicalize hostnames via a DNS lookup. */
  56 static int do_lookup;
  57
  58 /* If nonzero, display only a list of usernames and count of
  59    the users logged on.
  60    Ignored for `who am i'. */
  61 static int short_list;
  62
  63 /* If nonzero, display the hours:minutes since each user has touched
  64    the keyboard, or "." if within the last minute, or "old" if
  65    not within the last day. */
  66 static int include_idle;
  67
  68 /* If nonzero, display a line at the top describing each field. */
  69 static int include_heading;
  70
  71 /* If nonzero, display a `+' for each user if mesg y, a `-' if mesg n,
  72    or a `?' if their tty cannot be statted. */
  73 static int include_mesg;
  74
  75 static struct option const longopts[] =
  76 {
  77   {"count", no_argument, NULL, 'q'},
  78   {"idle", no_argument, NULL, 'u'},
  79   {"heading", no_argument, NULL, 'H'},
  80   {"lookup", no_argument, NULL, 'l'},
  81   {"message", no_argument, NULL, 'T'},
  82   {"mesg", no_argument, NULL, 'T'},
  83   {"writable", no_argument, NULL, 'T'},
  84   {GETOPT_HELP_OPTION_DECL},
  85   {GETOPT_VERSION_OPTION_DECL},
  86   {NULL, 0, NULL, 0}
  87 };
  88
  89 /* Return a string representing the time between WHEN and the time
  90    that this function is first run. */
  91
  92 static const char *
  93 idle_string (time_t when)
  94 {
  95   static time_t now = 0;
  96   static char idle_hhmm[10];
  97   time_t seconds_idle;
  98
  99   if (now == 0)
 100     time (&now);
 101
 102   seconds_idle = now - when;
 103   if (seconds_idle < 60)        /* One minute. */
 104     return "  .  ";
 105   if (seconds_idle < (24 * 60 * 60)) /* One day. */
 106     {
 107       sprintf (idle_hhmm, "%02d:%02d",
 108                (int) (seconds_idle / (60 * 60)),
 109                (int) ((seconds_idle % (60 * 60)) / 60));
 110       return (const char *) idle_hhmm;
 111     }
 112   return _(" old ");
 113 }
 114
 115 /* Display a line of information about UTMP_ENT. */
 116
 117 static void
 118 print_entry (const STRUCT_UTMP *utmp_ent)
 119 {
 120   struct stat stats;
 121   time_t last_change;
 122   char mesg;
 123
 124 #define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
 125 #define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
 126
 127   char line[sizeof (utmp_ent->ut_line) + DEV_DIR_LEN + 1];
 128   time_t tm;
 129
 130   /* Copy ut_line into LINE, prepending `/dev/' if ut_line is not
 131      already an absolute pathname.  Some system may put the full,
 132      absolute pathname in ut_line.  */
 133   if (utmp_ent->ut_line[0] == '/')
 134     {
 135       strncpy (line, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
 136       line[sizeof (utmp_ent->ut_line)] = '\0';
 137     }
 138   else
 139     {
 140       strcpy (line, DEV_DIR_WITH_TRAILING_SLASH);
 141       strncpy (line + DEV_DIR_LEN, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
 142       line[DEV_DIR_LEN + sizeof (utmp_ent->ut_line)] = '\0';
 143     }
 144
 145   if (stat (line, &stats) == 0)
 146     {
 147       mesg = (stats.st_mode & S_IWGRP) ? '+' : '-';
 148       last_change = stats.st_atime;
 149     }
 150   else
 151     {
 152       mesg = '?';
 153       last_change = 0;
 154     }
 155
 156   printf ("%-8.*s", (int) sizeof (utmp_ent->ut_name), utmp_ent->ut_name);
 157   if (include_mesg)
 158     printf ("  %c  ", mesg);
 159   printf (" %-8.*s", (int) sizeof (utmp_ent->ut_line), utmp_ent->ut_line);
 160
 161   /* Don't take the address of UT_TIME_MEMBER directly.
 162      Ulrich Drepper wrote:
 163      ``... GNU libc (and perhaps other libcs as well) have extended
 164      utmp file formats which do not use a simple time_t ut_time field.
 165      In glibc, ut_time is a macro which selects for backward compatibility
 166      the tv_sec member of a struct timeval value.''  */
 167   tm = UT_TIME_MEMBER (utmp_ent);
 168   printf (" %-12.12s", ctime (&tm) + 4);
 169
 170   if (include_idle)
 171     {
 172       if (last_change)
 173         printf (" %s", idle_string (last_change));
 174       else
 175         printf ("   .  ");
 176     }
 177 #if HAVE_UT_HOST
 178   if (utmp_ent->ut_host[0] && do_lookup)
 179     {
 180       char ut_host[sizeof (utmp_ent->ut_host) + 1];
 181       char *host = 0, *display = 0;
 182
 183       /* Copy the host name into UT_HOST, and ensure it's nul terminated. */
 184       strncpy (ut_host, utmp_ent->ut_host, (int) sizeof (utmp_ent->ut_host));
 185       ut_host[sizeof (utmp_ent->ut_host)] = '\0';
 186
 187       /* Look for an X display.  */
 188       display = strrchr (ut_host, ':');
 189       if (display)
 190         *display++ = '\0';
 191
 192       if (*ut_host)
 193         /* See if we can canonicalize it.  */
 194         host = canon_host (ut_host);
 195       if (! host)
 196         host = ut_host;
 197
 198       if (display)
 199         printf (" (%s:%s)", host, display);
 200       else
 201         printf (" (%s)", host);
 202     }
 203 #endif
 204
 205   putchar ('\n');
 206 }
 207
 208 /* Print the username of each valid entry and the number of valid entries
 209    in UTMP_BUF, which should have N elements. */
 210
 211 static void
 212 list_entries_who (int n, const STRUCT_UTMP *utmp_buf)
 213 {
 214   int entries;
 215
 216   entries = 0;
 217   while (n--)
 218     {
 219       if (utmp_buf->ut_name[0]
 220 #ifdef USER_PROCESS
 221           && utmp_buf->ut_type == USER_PROCESS
 222 #endif
 223          )
 224         {
 225           char *trimmed_name;
 226
 227           trimmed_name = extract_trimmed_name (utmp_buf);
 228
 229           printf ("%s ", trimmed_name);
 230           free (trimmed_name);
 231           entries++;
 232         }
 233       utmp_buf++;
 234     }
 235   printf (_("\n# users=%u\n"), entries);
 236 }
 237
 238 static void
 239 print_heading (void)
 240 {
 241   printf ("%-8s ", _("USER"));
 242   if (include_mesg)
 243     printf (_("MESG "));
 244   printf ("%-8s ", _("LINE"));
 245   printf (_("LOGIN-TIME   "));
 246   if (include_idle)
 247     printf (_("IDLE  "));
 248   printf (_("FROM\n"));
 249 }
 250
 251 /* Display UTMP_BUF, which should have N entries. */
 252
 253 static void
 254 scan_entries (int n, const STRUCT_UTMP *utmp_buf)
 255 {
 256   if (include_heading)
 257     print_heading ();
 258
 259   while (n--)
 260     {
 261       if (utmp_buf->ut_name[0]
 262 #ifdef USER_PROCESS
 263           && utmp_buf->ut_type == USER_PROCESS
 264 #endif
 265          )
 266         print_entry (utmp_buf);
 267       utmp_buf++;
 268     }
 269 }
 270
 271 /* Display a list of who is on the system, according to utmp file FILENAME. */
 272
 273 static void
 274 who (const char *filename)
 275 {
 276   int n_users;
 277   STRUCT_UTMP *utmp_buf;
 278   int fail = read_utmp (filename, &n_users, &utmp_buf);
 279
 280   if (fail)
 281     error (1, errno, "%s", filename);
 282
 283   if (short_list)
 284     list_entries_who (n_users, utmp_buf);
 285   else
 286     scan_entries (n_users, utmp_buf);
 287 }
 288
 289 /* Search UTMP_CONTENTS, which should have N entries, for
 290    an entry with a `ut_line' field identical to LINE.
 291    Return the first matching entry found, or NULL if there
 292    is no matching entry. */
 293
 294 static const STRUCT_UTMP *
 295 search_entries (int n, const STRUCT_UTMP *utmp_buf, const char *line)
 296 {
 297   while (n--)
 298     {
 299       if (utmp_buf->ut_name[0]
 300 #ifdef USER_PROCESS
 301           && utmp_buf->ut_type == USER_PROCESS
 302 #endif
 303           && !strncmp (line, utmp_buf->ut_line, sizeof (utmp_buf->ut_line)))
 304         return utmp_buf;
 305       utmp_buf++;
 306     }
 307   return NULL;
 308 }
 309
 310 /* Display the entry in utmp file FILENAME for this tty on standard input,
 311    or nothing if there is no entry for it. */
 312
 313 static void
 314 who_am_i (const char *filename)
 315 {
 316   const STRUCT_UTMP *utmp_entry;
 317   STRUCT_UTMP *utmp_buf;
 318   char hostname[MAXHOSTNAMELEN + 1];
 319   char *tty;
 320   int fail;
 321   int n_users;
 322
 323   if (gethostname (hostname, MAXHOSTNAMELEN + 1))
 324     *hostname = 0;
 325
 326   if (include_heading)
 327     {
 328       printf ("%*s ", (int) strlen (hostname), " ");
 329       print_heading ();
 330     }
 331
 332   tty = ttyname (0);
 333   if (tty == NULL)
 334     return;
 335   tty += 5;                     /* Remove "/dev/".  */
 336
 337   fail = read_utmp (filename, &n_users, &utmp_buf);
 338
 339   if (fail)
 340     error (1, errno, "%s", filename);
 341
 342   utmp_entry = search_entries (n_users, utmp_buf, tty);
 343   if (utmp_entry == NULL)
 344     return;
 345
 346   printf ("%s!", hostname);
 347   print_entry (utmp_entry);
 348 }
 349
 350 void
 351 usage (int status)
 352 {
 353   if (status != 0)
 354     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 355              program_name);
 356   else
 357     {
 358       printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
 359       printf (_("\
 360 \n\
 361   -H, --heading     print line of column headings\n\
 362   -i, -u, --idle    add user idle time as HOURS:MINUTES, . or old\n\
 363   -l, --lookup      attempt to canonicalize hostnames via DNS\n\
 364   -m                only hostname and user associated with stdin\n\
 365   -q, --count       all login names and number of users logged on\n\
 366   -s                (ignored)\n\
 367   -T, -w, --mesg    add user's message status as +, - or ?\n\
 368       --message     same as -T\n\
 369       --writable    same as -T\n\
 370       --help        display this help and exit\n\
 371       --version     output version information and exit\n\
 372 \n\
 373 If FILE is not specified, use %s.  %s as FILE is common.\n\
 374 If ARG1 ARG2 given, -m presumed: `am i' or `mom likes' are usual.\n\
 375 "), UTMP_FILE, WTMP_FILE);
 376       puts (_("\nReport bugs to <bug-sh-utils@gnu.org>."));
 377     }
 378   exit (status);
 379 }
 380
 381 int
 382 main (int argc, char **argv)
 383 {
 384   int optc, longind;
 385   int my_line_only = 0;
 386
 387   program_name = argv[0];
 388   setlocale (LC_ALL, "");
 389   bindtextdomain (PACKAGE, LOCALEDIR);
 390   textdomain (PACKAGE);
 391
 392   while ((optc = getopt_long (argc, argv, "ilmqsuwHT", longopts, &longind))
 393          != -1)
 394     {
 395       switch (optc)
 396         {
 397         case 0:
 398           break;
 399
 400         case 'm':
 401           my_line_only = 1;
 402           break;
 403
 404         case 'l':
 405           do_lookup = 1;
 406           break;
 407
 408         case 'q':
 409           short_list = 1;
 410           break;
 411
 412         case 's':
 413           break;
 414
 415         case 'i':
 416         case 'u':
 417           include_idle = 1;
 418           break;
 419
 420         case 'H':
 421           include_heading = 1;
 422           break;
 423
 424         case 'w':
 425         case 'T':
 426           include_mesg = 1;
 427           break;
 428
 429         case_GETOPT_HELP_CHAR;
 430
 431         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 432
 433         default:
 434           usage (1);
 435         }
 436     }
 437
 438   switch (argc - optind)
 439     {
 440     case 0:                     /* who */
 441       if (my_line_only)
 442         who_am_i (UTMP_FILE);
 443       else
 444         who (UTMP_FILE);
 445       break;
 446
 447     case 1:                     /* who <utmp file> */
 448       if (my_line_only)
 449         who_am_i (argv[optind]);
 450       else
 451         who (argv[optind]);
 452       break;
 453
 454     case 2:                     /* who <blurf> <glop> */
 455       who_am_i (UTMP_FILE);
 456       break;
 457
 458     default:                    /* lose */
 459       error (0, 0, _("too many arguments"));
 460       usage (1);
 461     }
 462
 463   exit (0);
 464 }