src/who.c

   1 /* GNU's who.
   2    Copyright (C) 1992-2024 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 <https://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 "hard-locale.h"
  37 #include "quote.h"
  38
  39 #ifdef TTY_GROUP_NAME
  40 # include <grp.h>
  41 #endif
  42
  43 /* The official name of this program (e.g., no 'g' prefix).  */
  44 #define PROGRAM_NAME "who"
  45
  46 #define AUTHORS \
  47   proper_name ("Joseph Arceneaux"), \
  48   proper_name ("David MacKenzie"), \
  49   proper_name ("Michael Stone")
  50
  51 #ifdef RUN_LVL
  52 # define UT_TYPE_RUN_LVL(U) ((U)->ut_type == RUN_LVL)
  53 #else
  54 # define UT_TYPE_RUN_LVL(U) false
  55 #endif
  56
  57 #ifdef INIT_PROCESS
  58 # define UT_TYPE_INIT_PROCESS(U) ((U)->ut_type == INIT_PROCESS)
  59 #else
  60 # define UT_TYPE_INIT_PROCESS(U) false
  61 #endif
  62
  63 #ifdef LOGIN_PROCESS
  64 # define UT_TYPE_LOGIN_PROCESS(U) ((U)->ut_type == LOGIN_PROCESS)
  65 #else
  66 # define UT_TYPE_LOGIN_PROCESS(U) false
  67 #endif
  68
  69 #ifdef DEAD_PROCESS
  70 # define UT_TYPE_DEAD_PROCESS(U) ((U)->ut_type == DEAD_PROCESS)
  71 #else
  72 # define UT_TYPE_DEAD_PROCESS(U) false
  73 #endif
  74
  75 #ifdef NEW_TIME
  76 # define UT_TYPE_NEW_TIME(U) ((U)->ut_type == NEW_TIME)
  77 #else
  78 # define UT_TYPE_NEW_TIME(U) false
  79 #endif
  80
  81 #define IDLESTR_LEN 6
  82
  83 #if HAVE_STRUCT_XTMP_UT_PID
  84 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  85   char Var[INT_STRLEN_BOUND (Utmp_ent->ut_pid) + 1]; \
  86   sprintf (Var, "%ld", (long int) (Utmp_ent->ut_pid))
  87 #else
  88 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  89   char const *Var = ""
  90 #endif
  91
  92 #if HAVE_STRUCT_XTMP_UT_ID
  93 # define UT_ID(U) ((U)->ut_id)
  94 #else
  95 # define UT_ID(U) "??"
  96 #endif
  97
  98 /* If true, attempt to canonicalize hostnames via a DNS lookup. */
  99 static bool do_lookup;
 100
 101 /* If true, display only a list of usernames and count of
 102    the users logged on.
 103    Ignored for 'who am i'.  */
 104 static bool short_list;
 105
 106 /* If true, display only name, line, and time fields.  */
 107 static bool short_output;
 108
 109 /* If true, display the hours:minutes since each user has touched
 110    the keyboard, or "." if within the last minute, or "old" if
 111    not within the last day.  */
 112 static bool include_idle;
 113
 114 /* If true, display a line at the top describing each field.  */
 115 static bool include_heading;
 116
 117 /* If true, display a '+' for each user if mesg y, a '-' if mesg n,
 118    or a '?' if their tty cannot be statted. */
 119 static bool include_mesg;
 120
 121 /* If true, display process termination & exit status.  */
 122 static bool include_exit;
 123
 124 /* If true, display the last boot time.  */
 125 static bool need_boottime;
 126
 127 /* If true, display dead processes.  */
 128 static bool need_deadprocs;
 129
 130 /* If true, display processes waiting for user login.  */
 131 static bool need_login;
 132
 133 /* If true, display processes started by init.  */
 134 static bool need_initspawn;
 135
 136 /* If true, display the last clock change.  */
 137 static bool need_clockchange;
 138
 139 /* If true, display the current runlevel.  */
 140 static bool need_runlevel;
 141
 142 /* If true, display user processes.  */
 143 static bool need_users;
 144
 145 /* If true, display info only for the controlling tty.  */
 146 static bool my_line_only;
 147
 148 /* The strftime format to use for login times, and its expected
 149    output width.  */
 150 static char const *time_format;
 151 static int time_format_width;
 152
 153 /* for long options with no corresponding short option, use enum */
 154 enum
 155 {
 156   LOOKUP_OPTION = CHAR_MAX + 1
 157 };
 158
 159 static struct option const longopts[] =
 160 {
 161   {"all", no_argument, nullptr, 'a'},
 162   {"boot", no_argument, nullptr, 'b'},
 163   {"count", no_argument, nullptr, 'q'},
 164   {"dead", no_argument, nullptr, 'd'},
 165   {"heading", no_argument, nullptr, 'H'},
 166   {"login", no_argument, nullptr, 'l'},
 167   {"lookup", no_argument, nullptr, LOOKUP_OPTION},
 168   {"message", no_argument, nullptr, 'T'},
 169   {"mesg", no_argument, nullptr, 'T'},
 170   {"process", no_argument, nullptr, 'p'},
 171   {"runlevel", no_argument, nullptr, 'r'},
 172   {"short", no_argument, nullptr, 's'},
 173   {"time", no_argument, nullptr, 't'},
 174   {"users", no_argument, nullptr, 'u'},
 175   {"writable", no_argument, nullptr, 'T'},
 176   {GETOPT_HELP_OPTION_DECL},
 177   {GETOPT_VERSION_OPTION_DECL},
 178   {nullptr, 0, nullptr, 0}
 179 };
 180
 181 /* Return a string representing the time between WHEN and now.
 182    BOOTTIME is the time of last reboot.
 183    FIXME: locale? */
 184 static char const *
 185 idle_string (time_t when, time_t boottime)
 186 {
 187   static time_t now = TYPE_MINIMUM (time_t);
 188
 189   if (now == TYPE_MINIMUM (time_t))
 190     time (&now);
 191
 192   int seconds_idle;
 193   if (boottime < when && when <= now
 194       && ! ckd_sub (&seconds_idle, now, when)
 195       && seconds_idle < 24 * 60 * 60)
 196     {
 197       if (seconds_idle < 60)
 198         return "  .  ";
 199       else
 200         {
 201           static char idle_hhmm[IDLESTR_LEN];
 202           sprintf (idle_hhmm, "%02d:%02d",
 203                    seconds_idle / (60 * 60),
 204                    (seconds_idle % (60 * 60)) / 60);
 205           return idle_hhmm;
 206         }
 207     }
 208
 209   return _(" old ");
 210 }
 211
 212 /* Return a time string.  */
 213 static char const *
 214 time_string (struct gl_utmp const *utmp_ent)
 215 {
 216   static char buf[INT_STRLEN_BOUND (intmax_t) + sizeof "-%m-%d %H:%M"];
 217   struct tm *tmp = localtime (&utmp_ent->ut_ts.tv_sec);
 218
 219   if (tmp)
 220     {
 221       strftime (buf, sizeof buf, time_format, tmp);
 222       return buf;
 223     }
 224   else
 225     return timetostr (utmp_ent->ut_ts.tv_sec, buf);
 226 }
 227
 228 /* Print formatted output line. Uses mostly arbitrary field sizes, probably
 229    will need tweaking if any of the localization stuff is done, or for 64 bit
 230    pids, etc. */
 231 static void
 232 print_line (char const *user, const char state,
 233             char const *line,
 234             char const *time_str, char const *idle, char const *pid,
 235             char const *comment, char const *exitstr)
 236 {
 237   static char mesg[3] = { ' ', 'x', '\0' };
 238   char *buf;
 239   char x_idle[1 + IDLESTR_LEN + 1];
 240   char x_pid[1 + INT_STRLEN_BOUND (pid_t) + 1];
 241   char *x_exitstr;
 242   int err;
 243
 244   mesg[1] = state;
 245
 246   if (include_idle && !short_output && strlen (idle) < sizeof x_idle - 1)
 247     sprintf (x_idle, " %-6s", idle);
 248   else
 249     *x_idle = '\0';
 250
 251   if (!short_output && strlen (pid) < sizeof x_pid - 1)
 252     sprintf (x_pid, " %10s", pid);
 253   else
 254     *x_pid = '\0';
 255
 256   x_exitstr = xmalloc (include_exit ? 1 + MAX (12, strlen (exitstr)) + 1 : 1);
 257   if (include_exit)
 258     sprintf (x_exitstr, " %-12s", exitstr);
 259   else
 260     *x_exitstr = '\0';
 261
 262   err = asprintf (&buf,
 263                   "%-8s"
 264                   "%s"
 265                   " %-12s"
 266                   " %-*s"
 267                   "%s"
 268                   "%s"
 269                   " %-8s"
 270                   "%s"
 271                   ,
 272                   user ? user : "   .",
 273                   include_mesg ? mesg : "",
 274                   line,
 275                   time_format_width,
 276                   time_str,
 277                   x_idle,
 278                   x_pid,
 279                   /* FIXME: it's not really clear whether the following
 280                      field should be in the short_output.  A strict reading
 281                      of SUSv2 would suggest not, but I haven't seen any
 282                      implementations that actually work that way... */
 283                   comment,
 284                   x_exitstr
 285                   );
 286   if (err == -1)
 287     xalloc_die ();
 288
 289   {
 290     /* Remove any trailing spaces.  */
 291     char *p = buf + strlen (buf);
 292     while (*--p == ' ')
 293       /* empty */;
 294     *(p + 1) = '\0';
 295   }
 296
 297   puts (buf);
 298   free (buf);
 299   free (x_exitstr);
 300 }
 301
 302 /* Return true if a terminal device given as PSTAT allows other users
 303    to send messages to; false otherwise */
 304 static bool
 305 is_tty_writable (struct stat const *pstat)
 306 {
 307 #ifdef TTY_GROUP_NAME
 308   /* Ensure the group of the TTY device matches TTY_GROUP_NAME, more info at
 309      https://bugzilla.redhat.com/454261 */
 310   struct group *ttygr = getgrnam (TTY_GROUP_NAME);
 311   if (!ttygr || (pstat->st_gid != ttygr->gr_gid))
 312     return false;
 313 #endif
 314
 315   return pstat->st_mode & S_IWGRP;
 316 }
 317
 318 /* Send properly parsed USER_PROCESS info to print_line.  The most
 319    recent boot time is BOOTTIME. */
 320 static void
 321 print_user (struct gl_utmp const *utmp_ent, time_t boottime)
 322 {
 323   struct stat stats;
 324   time_t last_change;
 325   char mesg;
 326   char idlestr[IDLESTR_LEN + 1];
 327   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 328   static char *hoststr;
 329 #if HAVE_STRUCT_XTMP_UT_HOST
 330   static idx_t hostlen;
 331 #endif
 332
 333   /* If ut_line contains a space, the device name starts after the space.  */
 334   char *line = utmp_ent->ut_line;
 335   char *space = strchr (line, ' ');
 336   line = space ? space + 1 : line;
 337
 338   int dirfd;
 339   if (IS_ABSOLUTE_FILE_NAME (line))
 340     dirfd = AT_FDCWD;
 341   else
 342     {
 343       static int dev_dirfd;
 344       if (!dev_dirfd)
 345         {
 346           dev_dirfd = open ("/dev", O_PATHSEARCH | O_DIRECTORY);
 347           if (dev_dirfd < 0)
 348             dev_dirfd = AT_FDCWD - 1;
 349         }
 350       dirfd = dev_dirfd;
 351     }
 352
 353   if (AT_FDCWD <= dirfd && fstatat (dirfd, line, &stats, 0) == 0)
 354     {
 355       mesg = is_tty_writable (&stats) ? '+' : '-';
 356       last_change = stats.st_atime;
 357     }
 358   else
 359     {
 360       mesg = '?';
 361       last_change = 0;
 362     }
 363
 364   if (last_change)
 365     sprintf (idlestr, "%.*s", IDLESTR_LEN, idle_string (last_change, boottime));
 366   else
 367     sprintf (idlestr, "  ?");
 368
 369 #if HAVE_STRUCT_XTMP_UT_HOST
 370   if (utmp_ent->ut_host[0])
 371     {
 372       char *host = nullptr;
 373       char *display = nullptr;
 374       char *ut_host = utmp_ent->ut_host;
 375
 376       /* Look for an X display.  */
 377       display = strchr (ut_host, ':');
 378       if (display)
 379         *display++ = '\0';
 380
 381       if (*ut_host && do_lookup)
 382         {
 383           /* See if we can canonicalize it.  */
 384           host = canon_host (ut_host);
 385         }
 386
 387       if (! host)
 388         host = ut_host;
 389
 390       if (display)
 391         {
 392           idx_t needed = strlen (host) + strlen (display) + 4;
 393           if (hostlen < needed)
 394             {
 395               free (hoststr);
 396               hoststr = xpalloc (nullptr, &hostlen, needed - hostlen, -1, 1);
 397             }
 398           char *p = hoststr;
 399           *p++ = '(';
 400           p = stpcpy (p, host);
 401           *p++ = ':';
 402           strcpy (stpcpy (p, display), ")");
 403         }
 404       else
 405         {
 406           idx_t needed = strlen (host) + 3;
 407           if (hostlen < needed)
 408             {
 409               free (hoststr);
 410               hoststr = xpalloc (nullptr, &hostlen, needed - hostlen, -1, 1);
 411             }
 412           char *p = hoststr;
 413           *p++ = '(';
 414           strcpy (stpcpy (p, host), ")");
 415         }
 416
 417       if (host != ut_host)
 418         free (host);
 419     }
 420   else
 421     {
 422       if (hostlen < 1)
 423         hoststr = xpalloc (hoststr, &hostlen, 1, -1, 1);
 424       *hoststr = '\0';
 425     }
 426 #endif
 427
 428   print_line (utmp_ent->ut_user, mesg,
 429               utmp_ent->ut_line,
 430               time_string (utmp_ent), idlestr, pidstr,
 431               hoststr ? hoststr : "", "");
 432 }
 433
 434 static void
 435 print_boottime (struct gl_utmp const *utmp_ent)
 436 {
 437   print_line ("", ' ', _("system boot"),
 438               time_string (utmp_ent), "", "", "", "");
 439 }
 440
 441 static char *
 442 make_id_equals_comment (struct gl_utmp const *utmp_ent)
 443 {
 444   char const *id = UT_ID (utmp_ent);
 445   idx_t idlen = strlen (id);
 446   char const *prefix = _("id=");
 447   idx_t prefixlen = strlen (prefix);
 448   char *comment = xmalloc (prefixlen + idlen + 1);
 449   char *p = mempcpy (comment, prefix, prefixlen);
 450   p = mempcpy (p, id, idlen);
 451   *p = '\0';
 452   return comment;
 453 }
 454
 455 static void
 456 print_deadprocs (struct gl_utmp const *utmp_ent)
 457 {
 458   static char *exitstr;
 459   char *comment = make_id_equals_comment (utmp_ent);
 460   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 461
 462   if (!exitstr)
 463     exitstr = xmalloc (strlen (_("term="))
 464                        + INT_STRLEN_BOUND (utmp_ent->ut_exit.e_termination) + 1
 465                        + strlen (_("exit="))
 466                        + INT_STRLEN_BOUND (utmp_ent->ut_exit.e_exit)
 467                        + 1);
 468   sprintf (exitstr, "%s%d %s%d", _("term="), utmp_ent->ut_exit.e_termination,
 469            _("exit="), utmp_ent->ut_exit.e_exit);
 470
 471   /* FIXME: add idle time? */
 472
 473   print_line ("", ' ', utmp_ent->ut_line,
 474               time_string (utmp_ent), "", pidstr, comment, exitstr);
 475   free (comment);
 476 }
 477
 478 static void
 479 print_login (struct gl_utmp const *utmp_ent)
 480 {
 481   char *comment = make_id_equals_comment (utmp_ent);
 482   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 483
 484   /* FIXME: add idle time? */
 485
 486   print_line (_("LOGIN"), ' ', utmp_ent->ut_line,
 487               time_string (utmp_ent), "", pidstr, comment, "");
 488   free (comment);
 489 }
 490
 491 static void
 492 print_initspawn (struct gl_utmp const *utmp_ent)
 493 {
 494   char *comment = make_id_equals_comment (utmp_ent);
 495   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 496
 497   print_line ("", ' ', utmp_ent->ut_line,
 498               time_string (utmp_ent), "", pidstr, comment, "");
 499   free (comment);
 500 }
 501
 502 static void
 503 print_clockchange (struct gl_utmp const *utmp_ent)
 504 {
 505   /* FIXME: handle NEW_TIME & OLD_TIME both */
 506   print_line ("", ' ', _("clock change"),
 507               time_string (utmp_ent), "", "", "", "");
 508 }
 509
 510 static void
 511 print_runlevel (struct gl_utmp const *utmp_ent)
 512 {
 513   static char *runlevline, *comment;
 514   unsigned char last = utmp_ent->ut_pid / 256;
 515   unsigned char curr = utmp_ent->ut_pid % 256;
 516
 517   if (!runlevline)
 518     runlevline = xmalloc (strlen (_("run-level")) + 3);
 519   sprintf (runlevline, "%s %c", _("run-level"), curr);
 520
 521   if (!comment)
 522     comment = xmalloc (strlen (_("last=")) + 2);
 523   sprintf (comment, "%s%c", _("last="), (last == 'N') ? 'S' : last);
 524
 525   print_line ("", ' ', runlevline, time_string (utmp_ent),
 526               "", "", c_isprint (last) ? comment : "", "");
 527
 528   return;
 529 }
 530
 531 /* Print the username of each valid entry and the number of valid entries
 532    in UTMP_BUF, which should have N elements. */
 533 static void
 534 list_entries_who (idx_t n, struct gl_utmp const *utmp_buf)
 535 {
 536   idx_t entries = 0;
 537   char const *separator = "";
 538
 539   while (n--)
 540     {
 541       if (IS_USER_PROCESS (utmp_buf))
 542         {
 543           char *trimmed_name;
 544
 545           trimmed_name = extract_trimmed_name (utmp_buf);
 546
 547           printf ("%s%s", separator, trimmed_name);
 548           free (trimmed_name);
 549           separator = " ";
 550           entries++;
 551         }
 552       utmp_buf++;
 553     }
 554   printf (_("\n# users=%td\n"), entries);
 555 }
 556
 557 static void
 558 print_heading (void)
 559 {
 560   print_line (_("NAME"), ' ', _("LINE"), _("TIME"), _("IDLE"),
 561               _("PID"), _("COMMENT"), _("EXIT"));
 562 }
 563
 564 /* Display UTMP_BUF, which should have N entries. */
 565 static void
 566 scan_entries (idx_t n, struct gl_utmp const *utmp_buf)
 567 {
 568   char *ttyname_b IF_LINT ( = nullptr);
 569   time_t boottime = TYPE_MINIMUM (time_t);
 570
 571   if (include_heading)
 572     print_heading ();
 573
 574   if (my_line_only)
 575     {
 576       ttyname_b = ttyname (STDIN_FILENO);
 577       if (!ttyname_b)
 578         return;
 579       if (STRNCMP_LIT (ttyname_b, "/dev/") == 0)
 580         ttyname_b += sizeof "/dev/" - 1;        /* Discard /dev/ prefix.  */
 581     }
 582
 583   while (n--)
 584     {
 585       if (!my_line_only
 586           || STREQ (ttyname_b, utmp_buf->ut_line))
 587         {
 588           if (need_users && IS_USER_PROCESS (utmp_buf))
 589             print_user (utmp_buf, boottime);
 590           else if (need_runlevel && UT_TYPE_RUN_LVL (utmp_buf))
 591             print_runlevel (utmp_buf);
 592           else if (need_boottime && UT_TYPE_BOOT_TIME (utmp_buf))
 593             print_boottime (utmp_buf);
 594           /* I've never seen one of these, so I don't know what it should
 595              look like :^)
 596              FIXME: handle OLD_TIME also, perhaps show the delta? */
 597           else if (need_clockchange && UT_TYPE_NEW_TIME (utmp_buf))
 598             print_clockchange (utmp_buf);
 599           else if (need_initspawn && UT_TYPE_INIT_PROCESS (utmp_buf))
 600             print_initspawn (utmp_buf);
 601           else if (need_login && UT_TYPE_LOGIN_PROCESS (utmp_buf))
 602             print_login (utmp_buf);
 603           else if (need_deadprocs && UT_TYPE_DEAD_PROCESS (utmp_buf))
 604             print_deadprocs (utmp_buf);
 605         }
 606
 607       if (UT_TYPE_BOOT_TIME (utmp_buf))
 608         boottime = utmp_buf->ut_ts.tv_sec;
 609
 610       utmp_buf++;
 611     }
 612 }
 613
 614 /* Display a list of who is on the system, according to utmp file FILENAME.
 615    Use read_utmp OPTIONS to read the file.  */
 616 static void
 617 who (char const *filename, int options)
 618 {
 619   idx_t n_users;
 620   struct gl_utmp *utmp_buf;
 621   if (short_list)
 622     options |= READ_UTMP_USER_PROCESS;
 623   if (read_utmp (filename, &n_users, &utmp_buf, options) != 0)
 624     error (EXIT_FAILURE, errno, "%s", quotef (filename));
 625
 626   if (short_list)
 627     list_entries_who (n_users, utmp_buf);
 628   else
 629     scan_entries (n_users, utmp_buf);
 630
 631   free (utmp_buf);
 632 }
 633
 634 void
 635 usage (int status)
 636 {
 637   if (status != EXIT_SUCCESS)
 638     emit_try_help ();
 639   else
 640     {
 641       printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
 642       fputs (_("\
 643 Print information about users who are currently logged in.\n\
 644 "), stdout);
 645       fputs (_("\
 646 \n\
 647   -a, --all         same as -b -d --login -p -r -t -T -u\n\
 648   -b, --boot        time of last system boot\n\
 649   -d, --dead        print dead processes\n\
 650   -H, --heading     print line of column headings\n\
 651 "), stdout);
 652       fputs (_("\
 653   -l, --login       print system login processes\n\
 654 "), stdout);
 655       fputs (_("\
 656       --lookup      attempt to canonicalize hostnames via DNS\n\
 657   -m                only hostname and user associated with stdin\n\
 658   -p, --process     print active processes spawned by init\n\
 659 "), stdout);
 660       fputs (_("\
 661   -q, --count       all login names and number of users logged on\n\
 662   -r, --runlevel    print current runlevel\n\
 663   -s, --short       print only name, line, and time (default)\n\
 664   -t, --time        print last system clock change\n\
 665 "), stdout);
 666       fputs (_("\
 667   -T, -w, --mesg    add user's message status as +, - or ?\n\
 668   -u, --users       list users logged in\n\
 669       --message     same as -T\n\
 670       --writable    same as -T\n\
 671 "), stdout);
 672       fputs (HELP_OPTION_DESCRIPTION, stdout);
 673       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 674       printf (_("\
 675 \n\
 676 If FILE is not specified, use %s.  %s as FILE is common.\n\
 677 If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.\n\
 678 "), UTMP_FILE, WTMP_FILE);
 679       emit_ancillary_info (PROGRAM_NAME);
 680     }
 681   exit (status);
 682 }
 683
 684 int
 685 main (int argc, char **argv)
 686 {
 687   int optc;
 688   bool assumptions = true;
 689
 690   initialize_main (&argc, &argv);
 691   set_program_name (argv[0]);
 692   setlocale (LC_ALL, "");
 693   bindtextdomain (PACKAGE, LOCALEDIR);
 694   textdomain (PACKAGE);
 695
 696   atexit (close_stdout);
 697
 698   while ((optc = getopt_long (argc, argv, "abdlmpqrstuwHT", longopts, nullptr))
 699          != -1)
 700     {
 701       switch (optc)
 702         {
 703         case 'a':
 704           need_boottime = true;
 705           need_deadprocs = true;
 706           need_login = true;
 707           need_initspawn = true;
 708           need_runlevel = true;
 709           need_clockchange = true;
 710           need_users = true;
 711           include_mesg = true;
 712           include_idle = true;
 713           include_exit = true;
 714           assumptions = false;
 715           break;
 716
 717         case 'b':
 718           need_boottime = true;
 719           assumptions = false;
 720           break;
 721
 722         case 'd':
 723           need_deadprocs = true;
 724           include_idle = true;
 725           include_exit = true;
 726           assumptions = false;
 727           break;
 728
 729         case 'H':
 730           include_heading = true;
 731           break;
 732
 733         case 'l':
 734           need_login = true;
 735           include_idle = true;
 736           assumptions = false;
 737           break;
 738
 739         case 'm':
 740           my_line_only = true;
 741           break;
 742
 743         case 'p':
 744           need_initspawn = true;
 745           assumptions = false;
 746           break;
 747
 748         case 'q':
 749           short_list = true;
 750           break;
 751
 752         case 'r':
 753           need_runlevel = true;
 754           include_idle = true;
 755           assumptions = false;
 756           break;
 757
 758         case 's':
 759           short_output = true;
 760           break;
 761
 762         case 't':
 763           need_clockchange = true;
 764           assumptions = false;
 765           break;
 766
 767         case 'T':
 768         case 'w':
 769           include_mesg = true;
 770           break;
 771
 772         case 'u':
 773           need_users = true;
 774           include_idle = true;
 775           assumptions = false;
 776           break;
 777
 778         case LOOKUP_OPTION:
 779           do_lookup = true;
 780           break;
 781
 782         case_GETOPT_HELP_CHAR;
 783
 784         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 785
 786         default:
 787           usage (EXIT_FAILURE);
 788         }
 789     }
 790
 791   if (assumptions)
 792     {
 793       need_users = true;
 794       short_output = true;
 795     }
 796
 797   if (include_exit)
 798     {
 799       short_output = false;
 800     }
 801
 802   if (hard_locale (LC_TIME))
 803     {
 804       time_format = "%Y-%m-%d %H:%M";
 805       time_format_width = 4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2;
 806     }
 807   else
 808     {
 809       time_format = "%b %e %H:%M";
 810       time_format_width = 3 + 1 + 2 + 1 + 2 + 1 + 2;
 811     }
 812
 813   switch (argc - optind)
 814     {
 815     case 2:                     /* who <blurf> <glop> */
 816       my_line_only = true;
 817       FALLTHROUGH;
 818     case -1:
 819     case 0:                     /* who */
 820       who (UTMP_FILE, READ_UTMP_CHECK_PIDS);
 821       break;
 822
 823     case 1:                     /* who <utmp file> */
 824       who (argv[optind], 0);
 825       break;
 826
 827     default:                    /* lose */
 828       error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
 829       usage (EXIT_FAILURE);
 830     }
 831
 832   return EXIT_SUCCESS;
 833 }