src/who.c

   1 /* GNU's who.
   2    Copyright (C) 1992-2022 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 #include <assert.h>
  30
  31 #include <sys/types.h>
  32 #include "system.h"
  33
  34 #include "c-ctype.h"
  35 #include "canon-host.h"
  36 #include "readutmp.h"
  37 #include "die.h"
  38 #include "error.h"
  39 #include "hard-locale.h"
  40 #include "quote.h"
  41
  42 #ifdef TTY_GROUP_NAME
  43 # include <grp.h>
  44 #endif
  45
  46 /* The official name of this program (e.g., no 'g' prefix).  */
  47 #define PROGRAM_NAME "who"
  48
  49 #define AUTHORS \
  50   proper_name ("Joseph Arceneaux"), \
  51   proper_name ("David MacKenzie"), \
  52   proper_name ("Michael Stone")
  53
  54 #ifdef RUN_LVL
  55 # define UT_TYPE_RUN_LVL(U) UT_TYPE_EQ (U, RUN_LVL)
  56 #else
  57 # define UT_TYPE_RUN_LVL(U) false
  58 #endif
  59
  60 #ifdef INIT_PROCESS
  61 # define UT_TYPE_INIT_PROCESS(U) UT_TYPE_EQ (U, INIT_PROCESS)
  62 #else
  63 # define UT_TYPE_INIT_PROCESS(U) false
  64 #endif
  65
  66 #ifdef LOGIN_PROCESS
  67 # define UT_TYPE_LOGIN_PROCESS(U) UT_TYPE_EQ (U, LOGIN_PROCESS)
  68 #else
  69 # define UT_TYPE_LOGIN_PROCESS(U) false
  70 #endif
  71
  72 #ifdef DEAD_PROCESS
  73 # define UT_TYPE_DEAD_PROCESS(U) UT_TYPE_EQ (U, DEAD_PROCESS)
  74 #else
  75 # define UT_TYPE_DEAD_PROCESS(U) false
  76 #endif
  77
  78 #ifdef NEW_TIME
  79 # define UT_TYPE_NEW_TIME(U) UT_TYPE_EQ (U, NEW_TIME)
  80 #else
  81 # define UT_TYPE_NEW_TIME(U) false
  82 #endif
  83
  84 #define IDLESTR_LEN 6
  85
  86 #if HAVE_STRUCT_XTMP_UT_PID
  87 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  88   char Var[INT_STRLEN_BOUND (Utmp_ent->ut_pid) + 1]; \
  89   sprintf (Var, "%ld", (long int) (Utmp_ent->ut_pid))
  90 #else
  91 # define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  92   char const *Var = ""
  93 #endif
  94
  95 #if HAVE_STRUCT_XTMP_UT_ID
  96 # define UT_ID(U) ((U)->ut_id)
  97 #else
  98 # define UT_ID(U) "??"
  99 #endif
 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 char const *
 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           /* FIXME-in-2018: see if this assert is still required in order
 204              to suppress gcc's unwarranted -Wformat-length= warning.  */
 205           assert (seconds_idle / (60 * 60) < 24);
 206           sprintf (idle_hhmm, "%02d:%02d",
 207                    seconds_idle / (60 * 60),
 208                    (seconds_idle % (60 * 60)) / 60);
 209           return idle_hhmm;
 210         }
 211     }
 212
 213   return _(" old ");
 214 }
 215
 216 /* Return a time string.  */
 217 static char const *
 218 time_string (const STRUCT_UTMP *utmp_ent)
 219 {
 220   static char buf[INT_STRLEN_BOUND (intmax_t) + sizeof "-%m-%d %H:%M"];
 221
 222   /* Don't take the address of UT_TIME_MEMBER directly.
 223      Ulrich Drepper wrote:
 224      "... GNU libc (and perhaps other libcs as well) have extended
 225      utmp file formats which do not use a simple time_t ut_time field.
 226      In glibc, ut_time is a macro which selects for backward compatibility
 227      the tv_sec member of a struct timeval value."  */
 228   time_t t = UT_TIME_MEMBER (utmp_ent);
 229   struct tm *tmp = localtime (&t);
 230
 231   if (tmp)
 232     {
 233       strftime (buf, sizeof buf, time_format, tmp);
 234       return buf;
 235     }
 236   else
 237     return timetostr (t, buf);
 238 }
 239
 240 /* Print formatted output line. Uses mostly arbitrary field sizes, probably
 241    will need tweaking if any of the localization stuff is done, or for 64 bit
 242    pids, etc. */
 243 static void
 244 print_line (int userlen, char const *user, const char state,
 245             int linelen, char const *line,
 246             char const *time_str, char const *idle, char const *pid,
 247             char const *comment, char const *exitstr)
 248 {
 249   static char mesg[3] = { ' ', 'x', '\0' };
 250   char *buf;
 251   char x_idle[1 + IDLESTR_LEN + 1];
 252   char x_pid[1 + INT_STRLEN_BOUND (pid_t) + 1];
 253   char *x_exitstr;
 254   int err;
 255
 256   mesg[1] = state;
 257
 258   if (include_idle && !short_output && strlen (idle) < sizeof x_idle - 1)
 259     sprintf (x_idle, " %-6s", idle);
 260   else
 261     *x_idle = '\0';
 262
 263   if (!short_output && strlen (pid) < sizeof x_pid - 1)
 264     sprintf (x_pid, " %10s", pid);
 265   else
 266     *x_pid = '\0';
 267
 268   x_exitstr = xmalloc (include_exit ? 1 + MAX (12, strlen (exitstr)) + 1 : 1);
 269   if (include_exit)
 270     sprintf (x_exitstr, " %-12s", exitstr);
 271   else
 272     *x_exitstr = '\0';
 273
 274   err = asprintf (&buf,
 275                   "%-8.*s"
 276                   "%s"
 277                   " %-12.*s"
 278                   " %-*s"
 279                   "%s"
 280                   "%s"
 281                   " %-8s"
 282                   "%s"
 283                   ,
 284                   userlen, user ? user : "   .",
 285                   include_mesg ? mesg : "",
 286                   linelen, line,
 287                   time_format_width,
 288                   time_str,
 289                   x_idle,
 290                   x_pid,
 291                   /* FIXME: it's not really clear whether the following
 292                      field should be in the short_output.  A strict reading
 293                      of SUSv2 would suggest not, but I haven't seen any
 294                      implementations that actually work that way... */
 295                   comment,
 296                   x_exitstr
 297                   );
 298   if (err == -1)
 299     xalloc_die ();
 300
 301   {
 302     /* Remove any trailing spaces.  */
 303     char *p = buf + strlen (buf);
 304     while (*--p == ' ')
 305       /* empty */;
 306     *(p + 1) = '\0';
 307   }
 308
 309   puts (buf);
 310   free (buf);
 311   free (x_exitstr);
 312 }
 313
 314 /* Return true if a terminal device given as PSTAT allows other users
 315    to send messages to; false otherwise */
 316 static bool
 317 is_tty_writable (struct stat const *pstat)
 318 {
 319 #ifdef TTY_GROUP_NAME
 320   /* Ensure the group of the TTY device matches TTY_GROUP_NAME, more info at
 321      https://bugzilla.redhat.com/454261 */
 322   struct group *ttygr = getgrnam (TTY_GROUP_NAME);
 323   if (!ttygr || (pstat->st_gid != ttygr->gr_gid))
 324     return false;
 325 #endif
 326
 327   return pstat->st_mode & S_IWGRP;
 328 }
 329
 330 /* Send properly parsed USER_PROCESS info to print_line.  The most
 331    recent boot time is BOOTTIME. */
 332 static void
 333 print_user (const STRUCT_UTMP *utmp_ent, time_t boottime)
 334 {
 335   struct stat stats;
 336   time_t last_change;
 337   char mesg;
 338   char idlestr[IDLESTR_LEN + 1];
 339   static char *hoststr;
 340 #if HAVE_UT_HOST
 341   static size_t hostlen;
 342 #endif
 343
 344 #define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
 345 #define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
 346
 347   char line[sizeof (utmp_ent->ut_line) + DEV_DIR_LEN + 1];
 348   char *p = line;
 349   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 350
 351   /* Copy ut_line into LINE, prepending '/dev/' if ut_line is not
 352      already an absolute file name.  Some systems may put the full,
 353      absolute file name in ut_line.  */
 354   if ( ! IS_ABSOLUTE_FILE_NAME (utmp_ent->ut_line))
 355     p = stpcpy (p, DEV_DIR_WITH_TRAILING_SLASH);
 356   stzncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
 357
 358   if (stat (line, &stats) == 0)
 359     {
 360       mesg = is_tty_writable (&stats) ? '+' : '-';
 361       last_change = stats.st_atime;
 362     }
 363   else
 364     {
 365       mesg = '?';
 366       last_change = 0;
 367     }
 368
 369   if (last_change)
 370     sprintf (idlestr, "%.*s", IDLESTR_LEN, idle_string (last_change, boottime));
 371   else
 372     sprintf (idlestr, "  ?");
 373
 374 #if HAVE_UT_HOST
 375   if (utmp_ent->ut_host[0])
 376     {
 377       char ut_host[sizeof (utmp_ent->ut_host) + 1];
 378       char *host = NULL;
 379       char *display = NULL;
 380
 381       /* Copy the host name into UT_HOST, and ensure it's nul terminated. */
 382       stzncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host));
 383
 384       /* Look for an X display.  */
 385       display = strchr (ut_host, ':');
 386       if (display)
 387         *display++ = '\0';
 388
 389       if (*ut_host && do_lookup)
 390         {
 391           /* See if we can canonicalize it.  */
 392           host = canon_host (ut_host);
 393         }
 394
 395       if (! host)
 396         host = ut_host;
 397
 398       if (display)
 399         {
 400           if (hostlen < strlen (host) + strlen (display) + 4)
 401             {
 402               hostlen = strlen (host) + strlen (display) + 4;
 403               free (hoststr);
 404               hoststr = xmalloc (hostlen);
 405             }
 406           sprintf (hoststr, "(%s:%s)", host, display);
 407         }
 408       else
 409         {
 410           if (hostlen < strlen (host) + 3)
 411             {
 412               hostlen = strlen (host) + 3;
 413               free (hoststr);
 414               hoststr = xmalloc (hostlen);
 415             }
 416           sprintf (hoststr, "(%s)", host);
 417         }
 418
 419       if (host != ut_host)
 420         free (host);
 421     }
 422   else
 423     {
 424       if (hostlen < 1)
 425         {
 426           hostlen = 1;
 427           free (hoststr);
 428           hoststr = xmalloc (hostlen);
 429         }
 430       *hoststr = '\0';
 431     }
 432 #endif
 433
 434   print_line (sizeof UT_USER (utmp_ent), UT_USER (utmp_ent), mesg,
 435               sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 436               time_string (utmp_ent), idlestr, pidstr,
 437               hoststr ? hoststr : "", "");
 438 }
 439
 440 static void
 441 print_boottime (const STRUCT_UTMP *utmp_ent)
 442 {
 443   print_line (-1, "", ' ', -1, _("system boot"),
 444               time_string (utmp_ent), "", "", "", "");
 445 }
 446
 447 static char *
 448 make_id_equals_comment (STRUCT_UTMP const *utmp_ent)
 449 {
 450   size_t utmpsize = sizeof UT_ID (utmp_ent);
 451   char *comment = xmalloc (strlen (_("id=")) + utmpsize + 1);
 452
 453   char *p = stpcpy (comment, _("id="));
 454   stzncpy (p, UT_ID (utmp_ent), utmpsize);
 455   return comment;
 456 }
 457
 458 static void
 459 print_deadprocs (const STRUCT_UTMP *utmp_ent)
 460 {
 461   static char *exitstr;
 462   char *comment = make_id_equals_comment (utmp_ent);
 463   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 464
 465   if (!exitstr)
 466     exitstr = xmalloc (strlen (_("term="))
 467                        + INT_STRLEN_BOUND (UT_EXIT_E_TERMINATION (utmp_ent)) + 1
 468                        + strlen (_("exit="))
 469                        + INT_STRLEN_BOUND (UT_EXIT_E_EXIT (utmp_ent))
 470                        + 1);
 471   sprintf (exitstr, "%s%d %s%d", _("term="), UT_EXIT_E_TERMINATION (utmp_ent),
 472            _("exit="), UT_EXIT_E_EXIT (utmp_ent));
 473
 474   /* FIXME: add idle time? */
 475
 476   print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 477               time_string (utmp_ent), "", pidstr, comment, exitstr);
 478   free (comment);
 479 }
 480
 481 static void
 482 print_login (const STRUCT_UTMP *utmp_ent)
 483 {
 484   char *comment = make_id_equals_comment (utmp_ent);
 485   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 486
 487   /* FIXME: add idle time? */
 488
 489   print_line (-1, _("LOGIN"), ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 490               time_string (utmp_ent), "", pidstr, comment, "");
 491   free (comment);
 492 }
 493
 494 static void
 495 print_initspawn (const STRUCT_UTMP *utmp_ent)
 496 {
 497   char *comment = make_id_equals_comment (utmp_ent);
 498   PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
 499
 500   print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
 501               time_string (utmp_ent), "", pidstr, comment, "");
 502   free (comment);
 503 }
 504
 505 static void
 506 print_clockchange (const STRUCT_UTMP *utmp_ent)
 507 {
 508   /* FIXME: handle NEW_TIME & OLD_TIME both */
 509   print_line (-1, "", ' ', -1, _("clock change"),
 510               time_string (utmp_ent), "", "", "", "");
 511 }
 512
 513 static void
 514 print_runlevel (const STRUCT_UTMP *utmp_ent)
 515 {
 516   static char *runlevline, *comment;
 517   unsigned char last = UT_PID (utmp_ent) / 256;
 518   unsigned char curr = UT_PID (utmp_ent) % 256;
 519
 520   if (!runlevline)
 521     runlevline = xmalloc (strlen (_("run-level")) + 3);
 522   sprintf (runlevline, "%s %c", _("run-level"), curr);
 523
 524   if (!comment)
 525     comment = xmalloc (strlen (_("last=")) + 2);
 526   sprintf (comment, "%s%c", _("last="), (last == 'N') ? 'S' : last);
 527
 528   print_line (-1, "", ' ', -1, runlevline, time_string (utmp_ent),
 529               "", "", c_isprint (last) ? comment : "", "");
 530
 531   return;
 532 }
 533
 534 /* Print the username of each valid entry and the number of valid entries
 535    in UTMP_BUF, which should have N elements. */
 536 static void
 537 list_entries_who (size_t n, const STRUCT_UTMP *utmp_buf)
 538 {
 539   unsigned long int entries = 0;
 540   char const *separator = "";
 541
 542   while (n--)
 543     {
 544       if (IS_USER_PROCESS (utmp_buf))
 545         {
 546           char *trimmed_name;
 547
 548           trimmed_name = extract_trimmed_name (utmp_buf);
 549
 550           printf ("%s%s", separator, trimmed_name);
 551           free (trimmed_name);
 552           separator = " ";
 553           entries++;
 554         }
 555       utmp_buf++;
 556     }
 557   printf (_("\n# users=%lu\n"), entries);
 558 }
 559
 560 static void
 561 print_heading (void)
 562 {
 563   print_line (-1, _("NAME"), ' ', -1, _("LINE"), _("TIME"), _("IDLE"),
 564               _("PID"), _("COMMENT"), _("EXIT"));
 565 }
 566
 567 /* Display UTMP_BUF, which should have N entries. */
 568 static void
 569 scan_entries (size_t n, const STRUCT_UTMP *utmp_buf)
 570 {
 571   char *ttyname_b IF_LINT ( = NULL);
 572   time_t boottime = TYPE_MINIMUM (time_t);
 573
 574   if (include_heading)
 575     print_heading ();
 576
 577   if (my_line_only)
 578     {
 579       ttyname_b = ttyname (STDIN_FILENO);
 580       if (!ttyname_b)
 581         return;
 582       if (STRNCMP_LIT (ttyname_b, DEV_DIR_WITH_TRAILING_SLASH) == 0)
 583         ttyname_b += DEV_DIR_LEN;       /* Discard /dev/ prefix.  */
 584     }
 585
 586   while (n--)
 587     {
 588       if (!my_line_only
 589           || STREQ_LEN (ttyname_b, utmp_buf->ut_line,
 590                         sizeof (utmp_buf->ut_line)))
 591         {
 592           if (need_users && IS_USER_PROCESS (utmp_buf))
 593             print_user (utmp_buf, boottime);
 594           else if (need_runlevel && UT_TYPE_RUN_LVL (utmp_buf))
 595             print_runlevel (utmp_buf);
 596           else if (need_boottime && UT_TYPE_BOOT_TIME (utmp_buf))
 597             print_boottime (utmp_buf);
 598           /* I've never seen one of these, so I don't know what it should
 599              look like :^)
 600              FIXME: handle OLD_TIME also, perhaps show the delta? */
 601           else if (need_clockchange && UT_TYPE_NEW_TIME (utmp_buf))
 602             print_clockchange (utmp_buf);
 603           else if (need_initspawn && UT_TYPE_INIT_PROCESS (utmp_buf))
 604             print_initspawn (utmp_buf);
 605           else if (need_login && UT_TYPE_LOGIN_PROCESS (utmp_buf))
 606             print_login (utmp_buf);
 607           else if (need_deadprocs && UT_TYPE_DEAD_PROCESS (utmp_buf))
 608             print_deadprocs (utmp_buf);
 609         }
 610
 611       if (UT_TYPE_BOOT_TIME (utmp_buf))
 612         boottime = UT_TIME_MEMBER (utmp_buf);
 613
 614       utmp_buf++;
 615     }
 616 }
 617
 618 /* Display a list of who is on the system, according to utmp file FILENAME.
 619    Use read_utmp OPTIONS to read the file.  */
 620 static void
 621 who (char const *filename, int options)
 622 {
 623   size_t n_users;
 624   STRUCT_UTMP *utmp_buf;
 625
 626   if (read_utmp (filename, &n_users, &utmp_buf, options) != 0)
 627     die (EXIT_FAILURE, errno, "%s", quotef (filename));
 628
 629   if (short_list)
 630     list_entries_who (n_users, utmp_buf);
 631   else
 632     scan_entries (n_users, utmp_buf);
 633
 634   free (utmp_buf);
 635 }
 636
 637 void
 638 usage (int status)
 639 {
 640   if (status != EXIT_SUCCESS)
 641     emit_try_help ();
 642   else
 643     {
 644       printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
 645       fputs (_("\
 646 Print information about users who are currently logged in.\n\
 647 "), stdout);
 648       fputs (_("\
 649 \n\
 650   -a, --all         same as -b -d --login -p -r -t -T -u\n\
 651   -b, --boot        time of last system boot\n\
 652   -d, --dead        print dead processes\n\
 653   -H, --heading     print line of column headings\n\
 654 "), stdout);
 655       fputs (_("\
 656   -l, --login       print system login processes\n\
 657 "), stdout);
 658       fputs (_("\
 659       --lookup      attempt to canonicalize hostnames via DNS\n\
 660   -m                only hostname and user associated with stdin\n\
 661   -p, --process     print active processes spawned by init\n\
 662 "), stdout);
 663       fputs (_("\
 664   -q, --count       all login names and number of users logged on\n\
 665   -r, --runlevel    print current runlevel\n\
 666   -s, --short       print only name, line, and time (default)\n\
 667   -t, --time        print last system clock change\n\
 668 "), stdout);
 669       fputs (_("\
 670   -T, -w, --mesg    add user's message status as +, - or ?\n\
 671   -u, --users       list users logged in\n\
 672       --message     same as -T\n\
 673       --writable    same as -T\n\
 674 "), stdout);
 675       fputs (HELP_OPTION_DESCRIPTION, stdout);
 676       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 677       printf (_("\
 678 \n\
 679 If FILE is not specified, use %s.  %s as FILE is common.\n\
 680 If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.\n\
 681 "), UTMP_FILE, WTMP_FILE);
 682       emit_ancillary_info (PROGRAM_NAME);
 683     }
 684   exit (status);
 685 }
 686
 687 int
 688 main (int argc, char **argv)
 689 {
 690   int optc;
 691   bool assumptions = true;
 692
 693   initialize_main (&argc, &argv);
 694   set_program_name (argv[0]);
 695   setlocale (LC_ALL, "");
 696   bindtextdomain (PACKAGE, LOCALEDIR);
 697   textdomain (PACKAGE);
 698
 699   atexit (close_stdout);
 700
 701   while ((optc = getopt_long (argc, argv, "abdlmpqrstuwHT", longopts, NULL))
 702          != -1)
 703     {
 704       switch (optc)
 705         {
 706         case 'a':
 707           need_boottime = true;
 708           need_deadprocs = true;
 709           need_login = true;
 710           need_initspawn = true;
 711           need_runlevel = true;
 712           need_clockchange = true;
 713           need_users = true;
 714           include_mesg = true;
 715           include_idle = true;
 716           include_exit = true;
 717           assumptions = false;
 718           break;
 719
 720         case 'b':
 721           need_boottime = true;
 722           assumptions = false;
 723           break;
 724
 725         case 'd':
 726           need_deadprocs = true;
 727           include_idle = true;
 728           include_exit = true;
 729           assumptions = false;
 730           break;
 731
 732         case 'H':
 733           include_heading = true;
 734           break;
 735
 736         case 'l':
 737           need_login = true;
 738           include_idle = true;
 739           assumptions = false;
 740           break;
 741
 742         case 'm':
 743           my_line_only = true;
 744           break;
 745
 746         case 'p':
 747           need_initspawn = true;
 748           assumptions = false;
 749           break;
 750
 751         case 'q':
 752           short_list = true;
 753           break;
 754
 755         case 'r':
 756           need_runlevel = true;
 757           include_idle = true;
 758           assumptions = false;
 759           break;
 760
 761         case 's':
 762           short_output = true;
 763           break;
 764
 765         case 't':
 766           need_clockchange = true;
 767           assumptions = false;
 768           break;
 769
 770         case 'T':
 771         case 'w':
 772           include_mesg = true;
 773           break;
 774
 775         case 'u':
 776           need_users = true;
 777           include_idle = true;
 778           assumptions = false;
 779           break;
 780
 781         case LOOKUP_OPTION:
 782           do_lookup = true;
 783           break;
 784
 785         case_GETOPT_HELP_CHAR;
 786
 787         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 788
 789         default:
 790           usage (EXIT_FAILURE);
 791         }
 792     }
 793
 794   if (assumptions)
 795     {
 796       need_users = true;
 797       short_output = true;
 798     }
 799
 800   if (include_exit)
 801     {
 802       short_output = false;
 803     }
 804
 805   if (hard_locale (LC_TIME))
 806     {
 807       time_format = "%Y-%m-%d %H:%M";
 808       time_format_width = 4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2;
 809     }
 810   else
 811     {
 812       time_format = "%b %e %H:%M";
 813       time_format_width = 3 + 1 + 2 + 1 + 2 + 1 + 2;
 814     }
 815
 816   switch (argc - optind)
 817     {
 818     case 2:                     /* who <blurf> <glop> */
 819       my_line_only = true;
 820       FALLTHROUGH;
 821     case -1:
 822     case 0:                     /* who */
 823       who (UTMP_FILE, READ_UTMP_CHECK_PIDS);
 824       break;
 825
 826     case 1:                     /* who <utmp file> */
 827       who (argv[optind], 0);
 828       break;
 829
 830     default:                    /* lose */
 831       error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
 832       usage (EXIT_FAILURE);
 833     }
 834
 835   return EXIT_SUCCESS;
 836 }