src/who.c

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