src/who.c

   1 /* GNU's users/who.
   2    Copyright (C) 92, 93, 94, 1995 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
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, 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    Options:
  27    -m           Same as 'who am i', for POSIX.
  28    -q           Only user names and # logged on; overrides all other options.
  29    -s           Name, line, time (default).
  30    -i, -u       Idle hours and minutes; '.' means active in last minute;
  31                 'old' means idle for >24 hours.
  32    -H           Print column headings at top.
  33    -w, -T       -s plus mesg (+ or -, or ? if bad line). */
  34
  35 #include <config.h>
  36 #include <stdio.h>
  37 #include <sys/types.h>
  38
  39 #ifdef HAVE_UTMPX_H
  40 #include <utmpx.h>
  41 #define STRUCT_UTMP struct utmpx
  42 #else
  43 #include <utmp.h>
  44 #define STRUCT_UTMP struct utmp
  45 #endif
  46
  47 #include <time.h>
  48 #include <getopt.h>
  49 #ifdef HAVE_SYS_PARAM_H
  50 #include <sys/param.h>
  51 #endif
  52
  53 #include "system.h"
  54 #include "version.h"
  55 #include "error.h"
  56
  57 #if !defined (UTMP_FILE) && defined (_PATH_UTMP)        /* 4.4BSD.  */
  58 #define UTMP_FILE _PATH_UTMP
  59 #endif
  60
  61 #if defined (UTMPX_FILE)        /* Solaris, SysVr4 */
  62 #undef  UTMP_FILE
  63 #define UTMP_FILE UTMPX_FILE
  64 #endif
  65
  66 #ifndef UTMP_FILE
  67 #define UTMP_FILE "/etc/utmp"
  68 #endif
  69
  70 #ifndef MAXHOSTNAMELEN
  71 #define MAXHOSTNAMELEN 64
  72 #endif
  73
  74 #ifndef S_IWGRP
  75 #define S_IWGRP 020
  76 #endif
  77
  78 #ifdef WHO
  79 #define COMMAND_NAME "who"
  80 #else
  81 #ifdef USERS
  82 #define COMMAND_NAME "users"
  83 #else
  84  error You must define one of WHO and USERS.
  85 #endif /* USERS */
  86 #endif /* WHO */
  87
  88 int gethostname ();
  89 char *ttyname ();
  90 char *xmalloc ();
  91
  92 /* The name this program was run with. */
  93 char *program_name;
  94
  95 /* If non-zero, display usage information and exit.  */
  96 static int show_help;
  97
  98 /* If non-zero, print the version on standard output and exit.  */
  99 static int show_version;
 100
 101 #ifdef WHO
 102 /* If nonzero, display only a list of usernames and count of
 103    the users logged on.
 104    Ignored for `who am i'. */
 105 static int short_list;
 106
 107 /* If nonzero, display the hours:minutes since each user has touched
 108    the keyboard, or "." if within the last minute, or "old" if
 109    not within the last day. */
 110 static int include_idle;
 111
 112 /* If nonzero, display a line at the top describing each field. */
 113 static int include_heading;
 114
 115 /* If nonzero, display a `+' for each user if mesg y, a `-' if mesg n,
 116    or a `?' if their tty cannot be statted. */
 117 static int include_mesg;
 118 #endif /* WHO */
 119
 120 static struct option const longopts[] =
 121 {
 122 #ifdef WHO
 123   {"count", no_argument, NULL, 'q'},
 124   {"idle", no_argument, NULL, 'u'},
 125   {"heading", no_argument, NULL, 'H'},
 126   {"message", no_argument, NULL, 'T'},
 127   {"mesg", no_argument, NULL, 'T'},
 128   {"writable", no_argument, NULL, 'T'},
 129 #endif /* WHO */
 130   {"help", no_argument, &show_help, 1},
 131   {"version", no_argument, &show_version, 1},
 132   {NULL, 0, NULL, 0}
 133 };
 134
 135 static STRUCT_UTMP *utmp_contents;
 136
 137 #if defined (WHO) || defined (USERS)
 138
 139 /* Copy UT->ut_name into storage obtained from malloc.  Then remove any
 140    trailing spaces from the copy, NUL terminate it, and return the copy.  */
 141
 142 static char *
 143 extract_trimmed_name (const STRUCT_UTMP *ut)
 144 {
 145   char *p, *trimmed_name;
 146
 147   trimmed_name = xmalloc (sizeof (ut->ut_name) + 1);
 148   strncpy (trimmed_name, ut->ut_name, sizeof (ut->ut_name));
 149   /* Append a trailing space character.  Some systems pad names shorter than
 150      the maximum with spaces, others pad with NULs.  Remove any spaces.  */
 151   trimmed_name[sizeof (ut->ut_name)] = ' ';
 152   p = strchr (trimmed_name, ' ');
 153   if (p != NULL)
 154     *p = '\0';
 155   return trimmed_name;
 156 }
 157
 158 #endif /* WHO || USERS */
 159
 160 #if WHO
 161
 162 /* Return a string representing the time between WHEN and the time
 163    that this function is first run. */
 164
 165 static const char *
 166 idle_string (when)
 167      time_t when;
 168 {
 169   static time_t now = 0;
 170   static char idle[10];
 171   time_t seconds_idle;
 172
 173   if (now == 0)
 174     time (&now);
 175
 176   seconds_idle = now - when;
 177   if (seconds_idle < 60)        /* One minute. */
 178     return "  .  ";
 179   if (seconds_idle < (24 * 60 * 60)) /* One day. */
 180     {
 181       sprintf (idle, "%02d:%02d",
 182                (int) (seconds_idle / (60 * 60)),
 183                (int) ((seconds_idle % (60 * 60)) / 60));
 184       return (const char *) idle;
 185     }
 186   return " old ";
 187 }
 188
 189 /* Display a line of information about entry THIS. */
 190
 191 static void
 192 print_entry (this)
 193      STRUCT_UTMP *this;
 194 {
 195   struct stat stats;
 196   time_t last_change;
 197   char mesg;
 198
 199 #define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
 200 #define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
 201
 202   char line[sizeof (this->ut_line) + DEV_DIR_LEN + 1];
 203
 204   /* Copy ut_line into LINE, prepending `/dev/' if ut_line is not
 205      already an absolute pathname.  Some system may put the full,
 206      absolute pathname in ut_line.  */
 207   if (this->ut_line[0] == '/')
 208     {
 209       strncpy (line, this->ut_line, sizeof (this->ut_line));
 210       line[sizeof (this->ut_line)] = '\0';
 211     }
 212   else
 213     {
 214       strcpy (line, DEV_DIR_WITH_TRAILING_SLASH);
 215       strncpy (line + DEV_DIR_LEN, this->ut_line, sizeof (this->ut_line));
 216       line[DEV_DIR_LEN + sizeof (this->ut_line)] = '\0';
 217     }
 218
 219   if (stat (line, &stats) == 0)
 220     {
 221       mesg = (stats.st_mode & S_IWGRP) ? '+' : '-';
 222       last_change = stats.st_atime;
 223     }
 224   else
 225     {
 226       mesg = '?';
 227       last_change = 0;
 228     }
 229
 230   printf ("%-8.*s", (int) sizeof (this->ut_name), this->ut_name);
 231   if (include_mesg)
 232     printf ("  %c  ", mesg);
 233   printf (" %-8.*s", (int) sizeof (this->ut_line), this->ut_line);
 234
 235 #ifdef HAVE_UTMPX_H
 236   printf (" %-12.12s", ctime (&this->ut_tv.tv_sec) + 4);
 237 #else
 238   printf (" %-12.12s", ctime (&this->ut_time) + 4);
 239 #endif
 240
 241   if (include_idle)
 242     {
 243       if (last_change)
 244         printf (" %s", idle_string (last_change));
 245       else
 246         printf ("   .  ");
 247     }
 248 #ifdef HAVE_UT_HOST
 249   if (this->ut_host[0])
 250     printf (" (%-.*s)", (int) sizeof (this->ut_host), this->ut_host);
 251 #endif
 252
 253   putchar ('\n');
 254 }
 255
 256 /* Print the username of each valid entry and the number of valid entries
 257    in `utmp_contents', which should have N elements. */
 258
 259 static void
 260 list_entries_who (n)
 261      int n;
 262 {
 263   register STRUCT_UTMP *this = utmp_contents;
 264   int entries;
 265
 266   entries = 0;
 267   while (n--)
 268     {
 269       if (this->ut_name[0]
 270 #ifdef USER_PROCESS
 271           && this->ut_type == USER_PROCESS
 272 #endif
 273          )
 274         {
 275           char *trimmed_name;
 276
 277           trimmed_name = extract_trimmed_name (this);
 278
 279           printf ("%s ", trimmed_name);
 280           free (trimmed_name);
 281           entries++;
 282         }
 283       this++;
 284     }
 285   printf ("\n# users=%u\n", entries);
 286 }
 287
 288 #endif /* WHO */
 289
 290 #ifdef USERS
 291
 292 static int
 293 userid_compare (v_a, v_b)
 294      const void *v_a;
 295      const void *v_b;
 296 {
 297   char **a = (char **) v_a;
 298   char **b = (char **) v_b;
 299   return strcmp (*a, *b);
 300 }
 301
 302 static void
 303 list_entries_users (n)
 304      int n;
 305 {
 306   register STRUCT_UTMP *this = utmp_contents;
 307   char **u;
 308   int i;
 309   int n_entries;
 310
 311   n_entries = 0;
 312   u = (char **) xmalloc (n * sizeof (u[0]));
 313   for (i=0; i<n; i++)
 314     {
 315       if (this->ut_name[0]
 316 #ifdef USER_PROCESS
 317           && this->ut_type == USER_PROCESS
 318 #endif
 319          )
 320         {
 321           char *trimmed_name;
 322
 323           trimmed_name = extract_trimmed_name (this);
 324
 325           u[n_entries] = trimmed_name;
 326           ++n_entries;
 327         }
 328       this++;
 329     }
 330
 331   qsort (u, n_entries, sizeof (u[0]), userid_compare);
 332
 333   for (i=0; i<n_entries; i++)
 334     {
 335       int c;
 336       fputs (u[i], stdout);
 337       c = (i < n_entries-1 ? ' ' : '\n');
 338       putchar (c);
 339     }
 340
 341   for (i=0; i<n_entries; i++)
 342     free (u[i]);
 343   free (u);
 344 }
 345
 346 #endif /* USERS */
 347
 348 #ifdef WHO
 349
 350 static void
 351 print_heading ()
 352 {
 353   printf ("%-8s ", "USER");
 354   if (include_mesg)
 355     printf ("MESG ");
 356   printf ("%-8s ", "LINE");
 357   printf ("LOGIN-TIME   ");
 358   if (include_idle)
 359     printf ("IDLE  ");
 360   printf ("FROM\n");
 361 }
 362
 363 /* Display `utmp_contents', which should have N entries. */
 364
 365 static void
 366 scan_entries (n)
 367      int n;
 368 {
 369   register STRUCT_UTMP *this = utmp_contents;
 370
 371   if (include_heading)
 372     print_heading ();
 373
 374   while (n--)
 375     {
 376       if (this->ut_name[0]
 377 #ifdef USER_PROCESS
 378           && this->ut_type == USER_PROCESS
 379 #endif
 380          )
 381         print_entry (this);
 382       this++;
 383     }
 384 }
 385
 386 #endif /* WHO */
 387
 388 /* Read the utmp file FILENAME into UTMP_CONTENTS and return the
 389    number of entries it contains. */
 390
 391 static int
 392 read_utmp (filename)
 393      char *filename;
 394 {
 395   FILE *utmp;
 396   struct stat file_stats;
 397   int n_read;
 398   size_t size;
 399
 400   utmp = fopen (filename, "r");
 401   if (utmp == NULL)
 402     error (1, errno, "%s", filename);
 403
 404   fstat (fileno (utmp), &file_stats);
 405   size = file_stats.st_size;
 406   if (size > 0)
 407     utmp_contents = (STRUCT_UTMP *) xmalloc (size);
 408   else
 409     {
 410       fclose (utmp);
 411       return 0;
 412     }
 413
 414   /* Use < instead of != in case the utmp just grew.  */
 415   n_read = fread (utmp_contents, 1, size, utmp);
 416   if (ferror (utmp) || fclose (utmp) == EOF
 417       || n_read < size)
 418     error (1, errno, "%s", filename);
 419
 420   return size / sizeof (STRUCT_UTMP);
 421 }
 422
 423 /* Display a list of who is on the system, according to utmp file FILENAME. */
 424
 425 static void
 426 who (filename)
 427      char *filename;
 428 {
 429   int users;
 430
 431   users = read_utmp (filename);
 432 #ifdef WHO
 433   if (short_list)
 434     list_entries_who (users);
 435   else
 436     scan_entries (users);
 437 #else
 438 #ifdef USERS
 439   list_entries_users (users);
 440 #endif /* USERS */
 441 #endif /* WHO */
 442 }
 443
 444 #ifdef WHO
 445
 446 /* Search `utmp_contents', which should have N entries, for
 447    an entry with a `ut_line' field identical to LINE.
 448    Return the first matching entry found, or NULL if there
 449    is no matching entry. */
 450
 451 static STRUCT_UTMP *
 452 search_entries (n, line)
 453      int n;
 454      char *line;
 455 {
 456   register STRUCT_UTMP *this = utmp_contents;
 457
 458   while (n--)
 459     {
 460       if (this->ut_name[0]
 461 #ifdef USER_PROCESS
 462           && this->ut_type == USER_PROCESS
 463 #endif
 464           && !strncmp (line, this->ut_line, sizeof (this->ut_line)))
 465         return this;
 466       this++;
 467     }
 468   return NULL;
 469 }
 470
 471 /* Display the entry in utmp file FILENAME for this tty on standard input,
 472    or nothing if there is no entry for it. */
 473
 474 static void
 475 who_am_i (filename)
 476      char *filename;
 477 {
 478   register STRUCT_UTMP *utmp_entry;
 479   char hostname[MAXHOSTNAMELEN + 1];
 480   char *tty;
 481
 482   if (gethostname (hostname, MAXHOSTNAMELEN + 1))
 483     *hostname = 0;
 484
 485   if (include_heading)
 486     {
 487       printf ("%*s ", (int) strlen (hostname), " ");
 488       print_heading ();
 489     }
 490
 491   tty = ttyname (0);
 492   if (tty == NULL)
 493     return;
 494   tty += 5;                     /* Remove "/dev/".  */
 495
 496   utmp_entry = search_entries (read_utmp (filename), tty);
 497   if (utmp_entry == NULL)
 498     return;
 499
 500   printf ("%s!", hostname);
 501   print_entry (utmp_entry);
 502 }
 503
 504 static void
 505 usage (status)
 506      int status;
 507 {
 508   if (status != 0)
 509     fprintf (stderr, "Try `%s --help' for more information.\n",
 510              program_name);
 511   else
 512     {
 513       printf ("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n", program_name);
 514       printf ("\
 515 \n\
 516   -H, --heading     print line of column headings\n\
 517   -T, -w, --mesg    add user's message status as +, - or ?\n\
 518   -i, -u, --idle    add user idle time as HOURS:MINUTES, . or old\n\
 519   -m                only hostname and user associated with stdin\n\
 520   -q, --count       all login names and number of users logged on\n\
 521   -s                (ignored)\n\
 522       --help        display this help and exit\n\
 523       --message     same as -T\n\
 524       --version     output version information and exit\n\
 525       --writeable   same as -T\n\
 526 \n\
 527 If FILE not given, uses /etc/utmp.  /etc/wtmp as FILE is common.\n\
 528 If ARG1 ARG2 given, -m presumed: `am i' or `mom likes' are usual.\n\
 529 ");
 530     }
 531   exit (status);
 532 }
 533 #endif /* WHO */
 534
 535 #ifdef USERS
 536 static void
 537 usage (status)
 538      int status;
 539 {
 540   if (status != 0)
 541     fprintf (stderr, "Try `%s --help' for more information.\n",
 542              program_name);
 543   else
 544     {
 545       printf ("Usage: %s [OPTION]... [ FILE ]\n", program_name);
 546       printf ("\
 547 Output who is currently logged in according to FILE.\n\
 548 If FILE not given, uses /etc/utmp.  /etc/wtmp as FILE is common.\n\
 549 \n\
 550       --help        display this help and exit\n\
 551       --version     output version information and exit\n");
 552     }
 553   exit (status);
 554 }
 555 #endif /* USERS */
 556
 557 void
 558 main (argc, argv)
 559      int argc;
 560      char **argv;
 561 {
 562   int optc, longind;
 563 #ifdef WHO
 564   int my_line_only = 0;
 565 #endif /* WHO */
 566
 567   program_name = argv[0];
 568
 569 #ifdef WHO
 570   while ((optc = getopt_long (argc, argv, "imqsuwHT", longopts, &longind))
 571 #else
 572   while ((optc = getopt_long (argc, argv, "", longopts, &longind))
 573 #endif /* WHO */
 574          != EOF)
 575     {
 576       switch (optc)
 577         {
 578         case 0:
 579           break;
 580
 581 #ifdef WHO
 582         case 'm':
 583           my_line_only = 1;
 584           break;
 585
 586         case 'q':
 587           short_list = 1;
 588           break;
 589
 590         case 's':
 591           break;
 592
 593         case 'i':
 594         case 'u':
 595           include_idle = 1;
 596           break;
 597
 598         case 'H':
 599           include_heading = 1;
 600           break;
 601
 602         case 'w':
 603         case 'T':
 604           include_mesg = 1;
 605           break;
 606 #endif /* WHO */
 607
 608         default:
 609           error (0, 0, "too many arguments");
 610           usage (1);
 611         }
 612     }
 613
 614   if (show_version)
 615     {
 616       printf ("%s - %s\n", COMMAND_NAME, version_string);
 617       exit (0);
 618     }
 619
 620   if (show_help)
 621     usage (0);
 622
 623   switch (argc - optind)
 624     {
 625     case 0:                     /* who */
 626 #ifdef WHO
 627       if (my_line_only)
 628         who_am_i (UTMP_FILE);
 629       else
 630 #endif /* WHO */
 631         who (UTMP_FILE);
 632       break;
 633
 634     case 1:                     /* who <utmp file> */
 635 #ifdef WHO
 636       if (my_line_only)
 637         who_am_i (argv[optind]);
 638       else
 639 #endif /* WHO */
 640         who (argv[optind]);
 641       break;
 642
 643 #ifdef WHO
 644     case 2:                     /* who <blurf> <glop> */
 645       who_am_i (UTMP_FILE);
 646       break;
 647 #endif /* WHO */
 648
 649     default:                    /* lose */
 650       usage (1);
 651     }
 652
 653   exit (0);
 654 }