src/who.c

   1 /* GNU's who.
   2    Copyright (C) 1992-2011 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 3 of the License, or
   7    (at your option) 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, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by jla; revised by djm; revised again by mstone */
  18
  19 /* Output format:
  20    name [state] line time [activity] [pid] [comment] [exit]
  21    state: -T
  22    name, line, time: not -q
  23    idle: -u
  24 */
  25
  26 #include <config.h>
  27 #include <getopt.h>
  28 #include <stdio.h>
  29
  30 #include <sys/types.h>
  31 #include "system.h"
  32
  33 #include "c-ctype.h"
  34 #include "canon-host.h"
  35 #include "readutmp.h"
  36 #include "error.h"
  37 #include "hard-locale.h"
  38 #include "quote.h"
  39
  40 #ifdef TTY_GROUP_NAME
  41 # include <grp.h>
  42 #endif
  43
  44 /* The official name of this program (e.g., no `g' prefix).  */
  45 #define PROGRAM_NAME "who"
  46
  47 #define AUTHORS \
  48   proper_name ("Joseph Arceneaux"), \
  49   proper_name ("David MacKenzie"), \
  50   proper_name ("Michael Stone")
  51
  52 #ifdef RUN_LVL
  53 # define UT_TYPE_RUN_LVL(U) UT_TYPE_EQ (U, RUN_LVL)
  54 #else
  55 # define UT_TYPE_RUN_LVL(U) false
  56 #endif
  57
  58 #ifdef INIT_PROCESS
  59 # define UT_TYPE_INIT_PROCESS(U) UT_TYPE_EQ (U, INIT_PROCESS)
  60 #else
  61 # define UT_TYPE_INIT_PROCESS(U) false
  62 #endif
  63
  64 #ifdef LOGIN_PROCESS
  65 # define UT_TYPE_LOGIN_PROCESS(U) UT_TYPE_EQ (U, LOGIN_PROCESS)
  66 #else
  67 # define UT_TYPE_LOGIN_PROCESS(U) false
  68 #endif
  69
  70 #ifdef DEAD_PROCESS
  71 # define UT_TYPE_DEAD_PROCESS(U) UT_TYPE_EQ (U, DEAD_PROCESS)
  72 #else
  73 # define UT_TYPE_DEAD_PROCESS(U) false
  74 #endif
  75
  76 #ifdef NEW_TIME
  77 # define UT_TYPE_NEW_TIME(U) UT_TYPE_EQ (U, NEW_TIME)
  78 #else
  79 # define UT_TYPE_NEW_TIME(U) false
  80 #endif
  81
  82 #define IDLESTR_LEN 6
  83
  84 #if HAVE_STRUCT_XTMP_UT_PID
  85 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  86   char Var[INT_STRLEN_BOUND (Utmp_ent->ut_pid) + 1]; \
  87   sprintf (Var, "%ld", (long int) (Utmp_ent->ut_pid))
  88 #else
  89 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  90   const char *Var = ""
  91 #endif
  92
  93 #if HAVE_STRUCT_XTMP_UT_ID
  94 # define UT_ID(U) ((U)->ut_id)
  95 #else
  96 # define UT_ID(U) "??"
  97 #endif
  98
  99 char *ttyname (int);
 100
 101 /* If true, attempt to canonicalize hostnames via a DNS lookup. */
 102 static bool do_lookup;
 103
 104 /* If true, display only a list of usernames and count of
 105    the users logged on.
 106    Ignored for `who am i'.  */
 107 static bool short_list;
 108
 109 /* If true, display only name, line, and time fields.  */
 110 static bool short_output;
 111
 112 /* If true, display the hours:minutes since each user has touched
 113    the keyboard, or "." if within the last minute, or "old" if
 114    not within the last day.  */
 115 static bool include_idle;
 116
 117 /* If true, display a line at the top describing each field.  */
 118 static bool include_heading;
 119
 120 /* If true, display a `+' for each user if mesg y, a `-' if mesg n,
 121    or a `?' if their tty cannot be statted. */
 122 static bool include_mesg;
 123
 124 /* If true, display process termination & exit status.  */
 125 static bool include_exit;
 126
 127 /* If true, display the last boot time.  */
 128 static bool need_boottime;
 129
 130 /* If true, display dead processes.  */
 131 static bool need_deadprocs;
 132
 133 /* If true, display processes waiting for user login.  */
 134 static bool need_login;
 135
 136 /* If true, display processes started by init.  */
 137 static bool need_initspawn;
 138
 139 /* If true, display the last clock change.  */
 140 static bool need_clockchange;
 141
 142 /* If true, display the current runlevel.  */
 143 static bool need_runlevel;
 144
 145 /* If true, display user processes.  */
 146 static bool need_users;
 147
 148 /* If true, display info only for the controlling tty.  */
 149 static bool my_line_only;
 150
 151 /* The strftime format to use for login times, and its expected
 152    output width.  */
 153 static char const *time_format;
 154 static int time_format_width;
 155
 156 /* for long options with no corresponding short option, use enum */
 157 enum
 158 {
 159   LOOKUP_OPTION = CHAR_MAX + 1
 160 };
 161
 162 static struct option const longopts[] =
 163 {
 164   {"all", no_argument, NULL, 'a'},
 165   {"boot", no_argument, NULL, 'b'},
 166   {"count", no_argument, NULL, 'q'},
 167   {"dead", no_argument, NULL, 'd'},
 168   {"heading", no_argument, NULL, 'H'},
 169   {"login", no_argument, NULL, 'l'},
 170   {"lookup", no_argument, NULL, LOOKUP_OPTION},
 171   {"message", no_argument, NULL, 'T'},
 172   {"mesg", no_argument, NULL, 'T'},
 173   {"process", no_argument, NULL, 'p'},
 174   {"runlevel", no_argument, NULL, 'r'},
 175   {"short", no_argument, NULL, 's'},
 176   {"time", no_argument, NULL, 't'},
 177   {"users", no_argument, NULL, 'u'},
 178   {"writable", no_argument, NULL, 'T'},
 179   {GETOPT_HELP_OPTION_DECL},
 180   {GETOPT_VERSION_OPTION_DECL},
 181   {NULL, 0, NULL, 0}
 182 };
 183
 184 /* Return a string representing the time between WHEN and now.
 185    BOOTTIME is the time of last reboot.
 186    FIXME: locale? */
 187 static const char *
 188 idle_string (time_t when, time_t boottime)
 189 {
 190   static time_t now = TYPE_MINIMUM (time_t);
 191
 192   if (now == TYPE_MINIMUM (time_t))
 193     time (&now);
 194
 195   if (boottime < when && now - 24 * 60 * 60 < when && when <= now)
 196     {
 197       int seconds_idle = now - when;
 198       if (seconds_idle < 60)
 199         return "  .  ";
 200       else
 201         {
 202           static char idle_hhmm[IDLESTR_LEN];
 203           sprintf (idle_hhmm, "%02d:%02d",
 204                    seconds_idle / (60 * 60),
 205                    (seconds_idle % (60 * 60)) / 60);
 206           return idle_hhmm;
 207         }
 208     }
 209
 210   return _(" old ");
 211 }
 212
 213 /* Return a time string.  */
 214 static const char *
 215 time_string (const STRUCT_UTMP *utmp_ent)
 216 {
 217   static char buf[INT_STRLEN_BOUND (intmax_t) + sizeof "-%m-%d %H:%M"];
 218
 219   /* Don't take the address of UT_TIME_MEMBER directly.
 220      Ulrich Drepper wrote:
 221      ``... GNU libc (and perhaps other libcs as well) have extended
 222      utmp file formats which do not use a simple time_t ut_time field.
 223      In glibc, ut_time is a macro which selects for backward compatibility
 224      the tv_sec member of a struct timeval value.''  */
 225   time_t t = UT_TIME_MEMBER (utmp_ent);
 226   struct tm *tmp = localtime (&t);
 227
 228   if (tmp)
 229     {
 230       strftime (buf, sizeof buf, time_format, tmp);
 231       return buf;
 232     }
 233   else
 234     return timetostr (t, buf);
 235 }
 236
 237 /* Print formatted output line. Uses mostly arbitrary field sizes, probably
 238    will need tweaking if any of the localization stuff is done, or for 64 bit
 239    pids, etc. */
 240 static void
 241 print_line (int userlen, const char *user, const char state,
 242             int linelen, const char *line,
 243             const char *time_str, const char *idle, const char *pid,
 244             const char *comment, const char *exitstr)
 245 {
 246   static char mesg[3] = { ' ', 'x', '\0' };
 247   char *buf;
 248   char x_idle[1 + IDLESTR_LEN + 1];
 249   char x_pid[1 + INT_STRLEN_BOUND (pid_t) + 1];
 250   char *x_exitstr;
 251   int err;
 252
 253   mesg[1] = state;
 254
 255   if (include_idle && !short_output && strlen (idle) < sizeof x_idle - 1)
 256     sprintf (x_idle, " %-6s", idle);
 257   else
 258     *x_idle = '\0';
 259
 260   if (!short_output && strlen (pid) < sizeof x_pid - 1)
 261     sprintf (x_pid, " %10s", pid);
 262   else
 263     *x_pid = '\0';
 264
 265   x_exitstr = xmalloc (include_exit ? 1 + MAX (12, strlen (exitstr)) + 1 : 1);
 266   if (include_exit)
 267     sprintf (x_exitstr, " %-12s", exitstr);
 268   else
 269     *x_exitstr = '\0';
 270
 271   err = asprintf (&buf,
 272                   "%-8.*s"
 273                   "%s"
 274                   " %-12.*s"
 275                   " %-*s"
 276                   "%s"
 277                   "%s"
 278                   " %-8s"
 279                   "%s"
 280                   ,
 281                   userlen, user ? user : "   .",
 282                   include_mesg ? mesg : "",
 283                   linelen, line,
 284                   time_format_width,
 285                   time_str,
 286                   x_idle,
 287                   x_pid,
 288                   /* FIXME: it's not really clear whether the following
 289                      field should be in the short_output.  A strict reading
 290                      of SUSv2 would suggest not, but I haven't seen any
 291                      implementations that actually work that way... */
 292                   comment,
 293                   x_exitstr
 294                   );
 295   if (err == -1)
 296     xalloc_die ();
 297
 298   {
 299     /* Remove any trailing spaces.  */
 300     char *p = buf + strlen (buf);
 301     while (*--p == ' ')
 302       /* empty */;
 303     *(p + 1) = '\0';
 304   }
 305
 306   puts (buf);
 307   free (buf);
 308   free (x_exitstr);
 309 }
 310
 311 /* Return true if a terminal device given as PSTAT allows other users
 312    to send messages to; false otherwise */
 313 static bool
 314 is_tty_writable (struct stat const *pstat)
 315 {
 316 #ifdef TTY_GROUP_NAME
 317   /* Ensure the group of the TTY device matches TTY_GROUP_NAME, more info at
 318      https://bugzilla.redhat.com/454261 */
 319   struct group *ttygr = getgrnam (TTY_GROUP_NAME);
 320   if (!ttygr || (pstat->st_gid != ttygr->gr_gid))
 321     return false;
 322 #endif
 323
 324   return pstat->st_mode & S_IWGRP;
 325 }
 326
 327 /* Send properly parsed USER_PROCESS info to print_line.  The most
 328    recent boot time is BOOTTIME. */
 329 static void
 330 print_user (const STRUCT_UTMP *utmp_ent, time_t boottime)
 331 {
 332   struct stat stats;
 333   time_t last_change;
 334   char mesg;
 335   char idlestr[IDLESTR_LEN + 1];
 336   static char *hoststr;
 337 #if HAVE_UT_HOST
 338   static size_t hostlen;
 339 #endif
 340
 341 #define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
 342 #define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
 343
 344   char line[sizeof (utmp_ent->ut_line) + DEV_DIR_LEN + 1];
 345   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 346
 347   /* Copy ut_line into LINE, prepending `/dev/' if ut_line is not
 348      already an absolute file name.  Some systems may put the full,
 349      absolute file name in ut_line.  */
 350   if (utmp_ent->ut_line[0] == '/')
 351     {
 352       strncpy (line, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
 353       line[sizeof (utmp_ent->ut_line)] = '\0';
 354     }
 355   else
 356     {
 357       strcpy (line, DEV_DIR_WITH_TRAILING_SLASH);
 358       strncpy (line + DEV_DIR_LEN, utmp_ent->ut_line,
 359                sizeof (utmp_ent->ut_line));
 360       line[DEV_DIR_LEN + sizeof (utmp_ent->ut_line)] = '\0';
 361     }
 362
 363   if (stat (line, &stats) == 0)
 364     {
 365       mesg = is_tty_writable (&stats) ? '+' : '-';
 366       last_change = stats.st_atime;
 367     }
 368   else
 369     {
 370       mesg = '?';
 371       last_change = 0;
 372     }
 373
 374   if (last_change)
 375     sprintf (idlestr, "%.*s", IDLESTR_LEN, idle_string (last_change, boottime));
 376   else
 377     sprintf (idlestr, "  ?");
 378
 379 #if HAVE_UT_HOST
 380   if (utmp_ent->ut_host[0])
 381     {
 382       char ut_host[sizeof (utmp_ent->ut_host) + 1];
 383       char *host = NULL;
 384       char *display = NULL;
 385
 386       /* Copy the host name into UT_HOST, and ensure it's nul terminated. */
 387       strncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host));
 388       ut_host[sizeof (utmp_ent->ut_host)] = '\0';
 389
 390       /* Look for an X display.  */
 391       display = strchr (ut_host, ':');
 392       if (display)
 393         *display++ = '\0';
 394
 395       if (*ut_host && do_lookup)
 396         {
 397           /* See if we can canonicalize it.  */
 398           host = canon_host (ut_host);
 399         }
 400
 401       if (! host)
 402         host = ut_host;
 403
 404       if (display)
 405         {
 406           if (hostlen < strlen (host) + strlen (display) + 4)
 407             {
 408               hostlen = strlen (host) + strlen (display) + 4;
 409               free (hoststr);
 410               hoststr = xmalloc (hostlen);
 411             }
 412           sprintf (hoststr, "(%s:%s)", host, display);
 413         }
 414       else
 415         {
 416           if (hostlen < strlen (host) + 3)
 417             {
 418               hostlen = strlen (host) + 3;
 419               free (hoststr);
 420               hoststr = xmalloc (hostlen);
 421             }
 422           sprintf (hoststr, "(%s)", host);
 423         }
 424
 425       if (host != ut_host)
 426         free (host);
 427     }
 428   else
 429     {
 430       if (hostlen < 1)
 431         {
 432           hostlen = 1;
 433           free (hoststr);
 434           hoststr = xmalloc (hostlen);
 435         }
 436       *hoststr = '\0';
 437     }
 438 #endif
 439
 440   print_line (sizeof UT_USER (utmp_ent), UT_USER (utmp_ent), mesg,
 441               sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 442               time_string (utmp_ent), idlestr, pidstr,
 443               hoststr ? hoststr : "", "");
 444 }
 445
 446 static void
 447 print_boottime (const STRUCT_UTMP *utmp_ent)
 448 {
 449   print_line (-1, "", ' ', -1, _("system boot"),
 450               time_string (utmp_ent), "", "", "", "");
 451 }
 452
 453 static char *
 454 make_id_equals_comment (STRUCT_UTMP const *utmp_ent)
 455 {
 456   char *comment = xmalloc (strlen (_("id=")) + sizeof UT_ID (utmp_ent) + 1);
 457
 458   strcpy (comment, _("id="));
 459   strncat (comment, UT_ID (utmp_ent), sizeof UT_ID (utmp_ent));
 460   return comment;
 461 }
 462
 463 static void
 464 print_deadprocs (const STRUCT_UTMP *utmp_ent)
 465 {
 466   static char *exitstr;
 467   char *comment = make_id_equals_comment (utmp_ent);
 468   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 469
 470   if (!exitstr)
 471     exitstr = xmalloc (strlen (_("term="))
 472                        + INT_STRLEN_BOUND (UT_EXIT_E_TERMINATION (utmp_ent)) + 1
 473                        + strlen (_("exit="))
 474                        + INT_STRLEN_BOUND (UT_EXIT_E_EXIT (utmp_ent))
 475                        + 1);
 476   sprintf (exitstr, "%s%d %s%d", _("term="), UT_EXIT_E_TERMINATION (utmp_ent),
 477            _("exit="), UT_EXIT_E_EXIT (utmp_ent));
 478
 479   /* FIXME: add idle time? */
 480
 481   print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 482               time_string (utmp_ent), "", pidstr, comment, exitstr);
 483   free (comment);
 484 }
 485
 486 static void
 487 print_login (const STRUCT_UTMP *utmp_ent)
 488 {
 489   char *comment = make_id_equals_comment (utmp_ent);
 490   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 491
 492   /* FIXME: add idle time? */
 493
 494   print_line (-1, _("LOGIN"), ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 495               time_string (utmp_ent), "", pidstr, comment, "");
 496   free (comment);
 497 }
 498
 499 static void
 500 print_initspawn (const STRUCT_UTMP *utmp_ent)
 501 {
 502   char *comment = make_id_equals_comment (utmp_ent);
 503   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 504
 505   print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 506               time_string (utmp_ent), "", pidstr, comment, "");
 507   free (comment);
 508 }
 509
 510 static void
 511 print_clockchange (const STRUCT_UTMP *utmp_ent)
 512 {
 513   /* FIXME: handle NEW_TIME & OLD_TIME both */
 514   print_line (-1, "", ' ', -1, _("clock change"),
 515               time_string (utmp_ent), "", "", "", "");
 516 }
 517
 518 static void
 519 print_runlevel (const STRUCT_UTMP *utmp_ent)
 520 {
 521   static char *runlevline, *comment;
 522   unsigned char last = UT_PID (utmp_ent) / 256;
 523   unsigned char curr = UT_PID (utmp_ent) % 256;
 524
 525   if (!runlevline)
 526     runlevline = xmalloc (strlen (_("run-level")) + 3);
 527   sprintf (runlevline, "%s %c", _("run-level"), curr);
 528
 529   if (!comment)
 530     comment = xmalloc (strlen (_("last=")) + 2);
 531   sprintf (comment, "%s%c", _("last="), (last == 'N') ? 'S' : last);
 532
 533   print_line (-1, "", ' ', -1, runlevline, time_string (utmp_ent),
 534               "", "", c_isprint (last) ? comment : "", "");
 535
 536   return;
 537 }
 538
 539 /* Print the username of each valid entry and the number of valid entries
 540    in UTMP_BUF, which should have N elements. */
 541 static void
 542 list_entries_who (size_t n, const STRUCT_UTMP *utmp_buf)
 543 {
 544   unsigned long int entries = 0;
 545   char const *separator = "";
 546
 547   while (n--)
 548     {
 549       if (IS_USER_PROCESS (utmp_buf))
 550         {
 551           char *trimmed_name;
 552
 553           trimmed_name = extract_trimmed_name (utmp_buf);
 554
 555           printf ("%s%s", separator, trimmed_name);
 556           free (trimmed_name);
 557           separator = " ";
 558           entries++;
 559         }
 560       utmp_buf++;
 561     }
 562   printf (_("\n# users=%lu\n"), entries);
 563 }
 564
 565 static void
 566 print_heading (void)
 567 {
 568   print_line (-1, _("NAME"), ' ', -1, _("LINE"), _("TIME"), _("IDLE"),
 569               _("PID"), _("COMMENT"), _("EXIT"));
 570 }
 571
 572 /* Display UTMP_BUF, which should have N entries. */
 573 static void
 574 scan_entries (size_t n, const STRUCT_UTMP *utmp_buf)
 575 {
 576   char *ttyname_b IF_LINT ( = NULL);
 577   time_t boottime = TYPE_MINIMUM (time_t);
 578
 579   if (include_heading)
 580     print_heading ();
 581
 582   if (my_line_only)
 583     {
 584       ttyname_b = ttyname (STDIN_FILENO);
 585       if (!ttyname_b)
 586         return;
 587       if (STRNCMP_LIT (ttyname_b, DEV_DIR_WITH_TRAILING_SLASH) == 0)
 588         ttyname_b += DEV_DIR_LEN;       /* Discard /dev/ prefix.  */
 589     }
 590
 591   while (n--)
 592     {
 593       if (!my_line_only ||
 594           strncmp (ttyname_b, utmp_buf->ut_line,
 595                    sizeof (utmp_buf->ut_line)) == 0)
 596         {
 597           if (need_users && IS_USER_PROCESS (utmp_buf))
 598             print_user (utmp_buf, boottime);
 599           else if (need_runlevel && UT_TYPE_RUN_LVL (utmp_buf))
 600             print_runlevel (utmp_buf);
 601           else if (need_boottime && UT_TYPE_BOOT_TIME (utmp_buf))
 602             print_boottime (utmp_buf);
 603           /* I've never seen one of these, so I don't know what it should
 604              look like :^)
 605              FIXME: handle OLD_TIME also, perhaps show the delta? */
 606           else if (need_clockchange && UT_TYPE_NEW_TIME (utmp_buf))
 607             print_clockchange (utmp_buf);
 608           else if (need_initspawn && UT_TYPE_INIT_PROCESS (utmp_buf))
 609             print_initspawn (utmp_buf);
 610           else if (need_login && UT_TYPE_LOGIN_PROCESS (utmp_buf))
 611             print_login (utmp_buf);
 612           else if (need_deadprocs && UT_TYPE_DEAD_PROCESS (utmp_buf))
 613             print_deadprocs (utmp_buf);
 614         }
 615
 616       if (UT_TYPE_BOOT_TIME (utmp_buf))
 617         boottime = UT_TIME_MEMBER (utmp_buf);
 618
 619       utmp_buf++;
 620     }
 621 }
 622
 623 /* Display a list of who is on the system, according to utmp file FILENAME.
 624    Use read_utmp OPTIONS to read the file.  */
 625 static void
 626 who (const char *filename, int options)
 627 {
 628   size_t n_users;
 629   STRUCT_UTMP *utmp_buf;
 630
 631   if (read_utmp (filename, &n_users, &utmp_buf, options) != 0)
 632     error (EXIT_FAILURE, errno, "%s", filename);
 633
 634   if (short_list)
 635     list_entries_who (n_users, utmp_buf);
 636   else
 637     scan_entries (n_users, utmp_buf);
 638
 639   free (utmp_buf);
 640 }
 641
 642 void
 643 usage (int status)
 644 {
 645   if (status != EXIT_SUCCESS)
 646     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 647              program_name);
 648   else
 649     {
 650       printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
 651       fputs (_("\
 652 Print information about users who are currently logged in.\n\
 653 "), stdout);
 654       fputs (_("\
 655 \n\
 656   -a, --all         same as -b -d --login -p -r -t -T -u\n\
 657   -b, --boot        time of last system boot\n\
 658   -d, --dead        print dead processes\n\
 659   -H, --heading     print line of column headings\n\
 660 "), stdout);
 661       fputs (_("\
 662   -l, --login       print system login processes\n\
 663 "), stdout);
 664       fputs (_("\
 665       --lookup      attempt to canonicalize hostnames via DNS\n\
 666   -m                only hostname and user associated with stdin\n\
 667   -p, --process     print active processes spawned by init\n\
 668 "), stdout);
 669       fputs (_("\
 670   -q, --count       all login names and number of users logged on\n\
 671   -r, --runlevel    print current runlevel\n\
 672   -s, --short       print only name, line, and time (default)\n\
 673   -t, --time        print last system clock change\n\
 674 "), stdout);
 675       fputs (_("\
 676   -T, -w, --mesg    add user's message status as +, - or ?\n\
 677   -u, --users       list users logged in\n\
 678       --message     same as -T\n\
 679       --writable    same as -T\n\
 680 "), stdout);
 681       fputs (HELP_OPTION_DESCRIPTION, stdout);
 682       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 683       printf (_("\
 684 \n\
 685 If FILE is not specified, use %s.  %s as FILE is common.\n\
 686 If ARG1 ARG2 given, -m presumed: `am i' or `mom likes' are usual.\n\
 687 "), UTMP_FILE, WTMP_FILE);
 688       emit_ancillary_info ();
 689     }
 690   exit (status);
 691 }
 692
 693 int
 694 main (int argc, char **argv)
 695 {
 696   int optc;
 697   bool assumptions = true;
 698
 699   initialize_main (&argc, &argv);
 700   set_program_name (argv[0]);
 701   setlocale (LC_ALL, "");
 702   bindtextdomain (PACKAGE, LOCALEDIR);
 703   textdomain (PACKAGE);
 704
 705   atexit (close_stdout);
 706
 707   while ((optc = getopt_long (argc, argv, "abdlmpqrstuwHT", longopts, NULL))
 708          != -1)
 709     {
 710       switch (optc)
 711         {
 712         case 'a':
 713           need_boottime = true;
 714           need_deadprocs = true;
 715           need_login = true;
 716           need_initspawn = true;
 717           need_runlevel = true;
 718           need_clockchange = true;
 719           need_users = true;
 720           include_mesg = true;
 721           include_idle = true;
 722           include_exit = true;
 723           assumptions = false;
 724           break;
 725
 726         case 'b':
 727           need_boottime = true;
 728           assumptions = false;
 729           break;
 730
 731         case 'd':
 732           need_deadprocs = true;
 733           include_idle = true;
 734           include_exit = true;
 735           assumptions = false;
 736           break;
 737
 738         case 'H':
 739           include_heading = true;
 740           break;
 741
 742         case 'l':
 743           need_login = true;
 744           include_idle = true;
 745           assumptions = false;
 746           break;
 747
 748         case 'm':
 749           my_line_only = true;
 750           break;
 751
 752         case 'p':
 753           need_initspawn = true;
 754           assumptions = false;
 755           break;
 756
 757         case 'q':
 758           short_list = true;
 759           break;
 760
 761         case 'r':
 762           need_runlevel = true;
 763           include_idle = true;
 764           assumptions = false;
 765           break;
 766
 767         case 's':
 768           short_output = true;
 769           break;
 770
 771         case 't':
 772           need_clockchange = true;
 773           assumptions = false;
 774           break;
 775
 776         case 'T':
 777         case 'w':
 778           include_mesg = true;
 779           break;
 780
 781         case 'u':
 782           need_users = true;
 783           include_idle = true;
 784           assumptions = false;
 785           break;
 786
 787         case LOOKUP_OPTION:
 788           do_lookup = true;
 789           break;
 790
 791         case_GETOPT_HELP_CHAR;
 792
 793         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 794
 795         default:
 796           usage (EXIT_FAILURE);
 797         }
 798     }
 799
 800   if (assumptions)
 801     {
 802       need_users = true;
 803       short_output = true;
 804     }
 805
 806   if (include_exit)
 807     {
 808       short_output = false;
 809     }
 810
 811   if (hard_locale (LC_TIME))
 812     {
 813       time_format = "%Y-%m-%d %H:%M";
 814       time_format_width = 4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2;
 815     }
 816   else
 817     {
 818       time_format = "%b %e %H:%M";
 819       time_format_width = 3 + 1 + 2 + 1 + 2 + 1 + 2;
 820     }
 821
 822   switch (argc - optind)
 823     {
 824     case 2:                     /* who <blurf> <glop> */
 825       my_line_only = true;
 826       /* Fall through.  */
 827     case -1:
 828     case 0:                     /* who */
 829       who (UTMP_FILE, READ_UTMP_CHECK_PIDS);
 830       break;
 831
 832     case 1:                     /* who <utmp file> */
 833       who (argv[optind], 0);
 834       break;
 835
 836     default:                    /* lose */
 837       error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
 838       usage (EXIT_FAILURE);
 839     }
 840
 841   exit (EXIT_SUCCESS);
 842 }