kernel_who.c

#include <config.h>
#include <getopt.h>
#include <stdio.h>
#include <assert.h>
#include <sys/types.h>
#include "system.h"
#include "c-ctype.h"
#include "canon-host.h"
#include "readutmp.h"
#include "die.h"
#include "error.h"
#include "hard-locale.h"
#include "quote.h"
#ifdef TTY_GROUP_NAME
# include <grp.h>
#endif
#define PROGRAM_NAME "who"
#ifdef RUN_LVL
# define UT_TYPE_RUN_LVL(U) UT_TYPE_EQ (U, RUN_LVL)
#else
# define UT_TYPE_RUN_LVL(U) false
#endif

#ifdef INIT_PROCESS
# define UT_TYPE_INIT_PROCESS(U) UT_TYPE_EQ (U, INIT_PROCESS)
#else
# define UT_TYPE_INIT_PROCESS(U) false
#endif

#ifdef LOGIN_PROCESS
# define UT_TYPE_LOGIN_PROCESS(U) UT_TYPE_EQ (U, LOGIN_PROCESS)
#else
# define UT_TYPE_LOGIN_PROCESS(U) false
#endif

#ifdef DEAD_PROCESS
# define UT_TYPE_DEAD_PROCESS(U) UT_TYPE_EQ (U, DEAD_PROCESS)
#else
# define UT_TYPE_DEAD_PROCESS(U) false
#endif

#ifdef NEW_TIME
# define UT_TYPE_NEW_TIME(U) UT_TYPE_EQ (U, NEW_TIME)
#else
# define UT_TYPE_NEW_TIME(U) false
#endif

#define IDLESTR_LEN 6
#if HAVE_STRUCT_XTMP_UT_PID
# define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  char Var[INT_STRLEN_BOUND (Utmp_ent->ut_pid) + 1]; \
  sprintf (Var, "%ld", (long int) (Utmp_ent->ut_pid))
#else
# define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
  char const *Var = ""
#endif

#if HAVE_STRUCT_XTMP_UT_ID
# define UT_ID(U) ((U)->ut_id)
#else
# define UT_ID(U) "??"
#endif
static bool do_lookup;
static bool short_list;
static bool short_output;
static bool include_idle;
static bool include_heading;
static bool include_mesg;
static bool include_exit;
static bool need_boottime;
static bool need_deadprocs;
static bool need_login;
static bool need_initspawn;
static bool need_clockchange;
static bool need_runlevel;
static bool need_users;
static bool my_line_only;
static char const *time_format;
static int time_format_width;
enum
{
  LOOKUP_OPTION = CHAR_MAX + 1
};
static struct option const longopts[] =
{
  {"all", no_argument, NULL, 'a'},
  {"boot", no_argument, NULL, 'b'},
  {"count", no_argument, NULL, 'q'},
  {"dead", no_argument, NULL, 'd'},
  {"heading", no_argument, NULL, 'H'},
  {"login", no_argument, NULL, 'l'},
  {"lookup", no_argument, NULL, LOOKUP_OPTION},
  {"message", no_argument, NULL, 'T'},
  {"mesg", no_argument, NULL, 'T'},
  {"process", no_argument, NULL, 'p'},
  {"runlevel", no_argument, NULL, 'r'},
  {"short", no_argument, NULL, 's'},
  {"time", no_argument, NULL, 't'},
  {"users", no_argument, NULL, 'u'},
  {"writable", no_argument, NULL, 'T'},
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};
static char const *idle_string (time_t when, time_t boottime)
{
  static time_t now = TYPE_MINIMUM (time_t);
  if (now == TYPE_MINIMUM (time_t))
    time (&now);
  if (boottime < when && now - 24 * 60 * 60 < when && when <= now)
    {
      int seconds_idle = now - when;
      if (seconds_idle < 60)
        return "  .  ";
      else
        {
          static char idle_hhmm[IDLESTR_LEN];
          assert (seconds_idle / (60 * 60) < 24);
          sprintf (idle_hhmm, "%02d:%02d", seconds_idle / (60 * 60), (seconds_idle % (60 * 60)) / 60);
          return idle_hhmm;
        }
    }
  return _(" old ");
}
static char const *time_string (const STRUCT_UTMP *utmp_ent)
{
  static char buf[INT_STRLEN_BOUND (intmax_t) + sizeof "-%m-%d %H:%M"];
  time_t t = UT_TIME_MEMBER (utmp_ent);
  struct tm *tmp = localtime (&t);
  if (tmp)
    {
      strftime (buf, sizeof buf, time_format, tmp);
      return buf;
    }
  else
    return timetostr (t, buf);
}
static void print_line (int userlen, char const *user, const char state, int linelen, char const *line, char const *time_str, char const *idle, char const *pid, char const *comment, char const *exitstr)
{
  static char mesg[3] = { ' ', 'x', '\0' };
  char *buf;
  char x_idle[1 + IDLESTR_LEN + 1];
  char x_pid[1 + INT_STRLEN_BOUND (pid_t) + 1];
  char *x_exitstr;
  int err;
  mesg[1] = state;
  if (include_idle && !short_output && strlen (idle) < sizeof x_idle - 1)
    sprintf (x_idle, " %-6s", idle);
  else
    *x_idle = '\0';
  if (!short_output && strlen (pid) < sizeof x_pid - 1)
    sprintf (x_pid, " %10s", pid);
  else
    *x_pid = '\0';
  x_exitstr = xmalloc (include_exit ? 1 + MAX (12, strlen (exitstr)) + 1 : 1);
  if (include_exit)
    sprintf (x_exitstr, " %-12s", exitstr);
  else
    *x_exitstr = '\0';
  err = asprintf (&buf,
                  "%-8.*s"
                  "%s"
                  " %-12.*s"
                  " %-*s"
                  "%s"
                  "%s"
                  " %-8s"
                  "%s"
                  ,
                  userlen, user ? user : "   .", include_mesg ? mesg : "", linelen, line, time_format_width, time_str, x_idle, x_pid, comment, x_exitstr);
  if (err == -1)
    xalloc_die ();
  {
    char *p = buf + strlen (buf);
    while (*--p == ' ')
      ;
    *(p + 1) = '\0';
  }
  puts (buf);
  free (buf);
  free (x_exitstr);
}
static bool
is_tty_writable (struct stat const *pstat)
{
#ifdef TTY_GROUP_NAME
  struct group *ttygr = getgrnam (TTY_GROUP_NAME);
  if (!ttygr || (pstat->st_gid != ttygr->gr_gid))
    return false;
#endif
  return pstat->st_mode & S_IWGRP;
}
static void
print_user (const STRUCT_UTMP *utmp_ent, time_t boottime)
{
  struct stat stats;
  time_t last_change;
  char mesg;
  char idlestr[IDLESTR_LEN + 1];
  static char *hoststr;
#if HAVE_UT_HOST
  static size_t hostlen;
#endif
#define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
#define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
  char line[sizeof (utmp_ent->ut_line) + DEV_DIR_LEN + 1];
  char *p = line;
  PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
  if ( ! IS_ABSOLUTE_FILE_NAME (utmp_ent->ut_line))
    p = stpcpy (p, DEV_DIR_WITH_TRAILING_SLASH);
  stzncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
  if (stat (line, &stats) == 0)
    {
      mesg = is_tty_writable (&stats) ? '+' : '-';
      last_change = stats.st_atime;
    }
  else
    {
      mesg = '?';
      last_change = 0;
    }
  if (last_change)
    sprintf (idlestr, "%.*s", IDLESTR_LEN, idle_string (last_change, boottime));
  else
    sprintf (idlestr, "  ?");
#if HAVE_UT_HOST
  if (utmp_ent->ut_host[0])
    {
      char ut_host[sizeof (utmp_ent->ut_host) + 1];
      char *host = NULL;
      char *display = NULL;
      stzncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host));
      display = strchr (ut_host, ':');
      if (display)
        *display++ = '\0';
      if (*ut_host && do_lookup)
        {
          host = canon_host (ut_host);
        }
      if (! host)
        host = ut_host;
      if (display)
        {
          if (hostlen < strlen (host) + strlen (display) + 4)
            {
              hostlen = strlen (host) + strlen (display) + 4;
              free (hoststr);
              hoststr = xmalloc (hostlen);
            }
          sprintf (hoststr, "(%s:%s)", host, display);
        }
      else
        {
          if (hostlen < strlen (host) + 3)
            {
              hostlen = strlen (host) + 3;
              free (hoststr);
              hoststr = xmalloc (hostlen);
            }
          sprintf (hoststr, "(%s)", host);
        }
      if (host != ut_host)
        free (host);
    }
  else
    {
      if (hostlen < 1)
        {
          hostlen = 1;
          free (hoststr);
          hoststr = xmalloc (hostlen);
        }
      *hoststr = '\0';
    }
#endif
  print_line (sizeof UT_USER (utmp_ent), UT_USER (utmp_ent), mesg, sizeof utmp_ent->ut_line, utmp_ent->ut_line, time_string (utmp_ent), idlestr, pidstr, hoststr ? hoststr : "", "");
}
static void print_boottime (const STRUCT_UTMP *utmp_ent)
{
  print_line (-1, "", ' ', -1, _("system boot"), time_string (utmp_ent), "", "", "", "");
}
static char *make_id_equals_comment (STRUCT_UTMP const *utmp_ent)
{
  size_t utmpsize = sizeof UT_ID (utmp_ent);
  char *comment = xmalloc (strlen (_("id=")) + utmpsize + 1);
  char *p = stpcpy (comment, _("id="));
  stzncpy (p, UT_ID (utmp_ent), utmpsize);
  return comment;
}
static void print_deadprocs (const STRUCT_UTMP *utmp_ent)
{
  static char *exitstr;
  char *comment = make_id_equals_comment (utmp_ent);
  PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
  if (!exitstr)
    exitstr = xmalloc (strlen (_("term=")) + INT_STRLEN_BOUND (UT_EXIT_E_TERMINATION (utmp_ent)) + 1 + strlen (_("exit=")) + INT_STRLEN_BOUND (UT_EXIT_E_EXIT (utmp_ent)) + 1);
  sprintf (exitstr, "%s%d %s%d", _("term="), UT_EXIT_E_TERMINATION (utmp_ent), _("exit="), UT_EXIT_E_EXIT (utmp_ent));
  print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line, time_string (utmp_ent), "", pidstr, comment, exitstr);
  free (comment);
}
static void print_login (const STRUCT_UTMP *utmp_ent)
{
  char *comment = make_id_equals_comment (utmp_ent);
  PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
  print_line (-1, _("LOGIN"), ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line, time_string (utmp_ent), "", pidstr, comment, "");
  free (comment);
}
static void print_initspawn (const STRUCT_UTMP *utmp_ent)
{
  char *comment = make_id_equals_comment (utmp_ent);
  PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
  print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line, time_string (utmp_ent), "", pidstr, comment, "");
  free (comment);
}
static void print_clockchange (const STRUCT_UTMP *utmp_ent)
{
  print_line (-1, "", ' ', -1, _("clock change"), time_string (utmp_ent), "", "", "", "");
}
static void print_runlevel (const STRUCT_UTMP *utmp_ent)
{
  static char *runlevline, *comment;
  unsigned char last = UT_PID (utmp_ent) / 256;
  unsigned char curr = UT_PID (utmp_ent) % 256;
  if (!runlevline)
    runlevline = xmalloc (strlen (_("run-level")) + 3);
  sprintf (runlevline, "%s %c", _("run-level"), curr);
  if (!comment)
    comment = xmalloc (strlen (_("last=")) + 2);
  sprintf (comment, "%s%c", _("last="), (last == 'N') ? 'S' : last);
  print_line (-1, "", ' ', -1, runlevline, time_string (utmp_ent), "", "", c_isprint (last) ? comment : "", "");
  return;
}
static void list_entries_who (size_t n, const STRUCT_UTMP *utmp_buf)
{
  unsigned long int entries = 0;
  char const *separator = "";
  while (n--)
    {
      if (IS_USER_PROCESS (utmp_buf))
        {
          char *trimmed_name;
          trimmed_name = extract_trimmed_name (utmp_buf);
          printf ("%s%s", separator, trimmed_name);
          free (trimmed_name);
          separator = " ";
          entries++;
        }
      utmp_buf++;
    }
  printf (_("\n# users=%lu\n"), entries);
}
static void print_heading (void)
{
  print_line (-1, _("NAME"), ' ', -1, _("LINE"), _("TIME"), _("IDLE"), _("PID"), _("COMMENT"), _("EXIT"));
}
static void scan_entries (size_t n, const STRUCT_UTMP *utmp_buf)
{
  char *ttyname_b IF_LINT ( = NULL);
  time_t boottime = TYPE_MINIMUM (time_t);
  if (include_heading)
    print_heading ();
  if (my_line_only)
    {
      ttyname_b = ttyname (STDIN_FILENO);
      if (!ttyname_b)
        return;
      if (STRNCMP_LIT (ttyname_b, DEV_DIR_WITH_TRAILING_SLASH) == 0)
        ttyname_b += DEV_DIR_LEN;	
    }
  while (n--)
    {
      if (!my_line_only
          || STREQ_LEN (ttyname_b, utmp_buf->ut_line, sizeof (utmp_buf->ut_line)))
        {
          if (need_users && IS_USER_PROCESS (utmp_buf))
            print_user (utmp_buf, boottime);
          else if (need_runlevel && UT_TYPE_RUN_LVL (utmp_buf))
            print_runlevel (utmp_buf);
          else if (need_boottime && UT_TYPE_BOOT_TIME (utmp_buf))
            print_boottime (utmp_buf);
          else if (need_clockchange && UT_TYPE_NEW_TIME (utmp_buf))
            print_clockchange (utmp_buf);
          else if (need_initspawn && UT_TYPE_INIT_PROCESS (utmp_buf))
            print_initspawn (utmp_buf);
          else if (need_login && UT_TYPE_LOGIN_PROCESS (utmp_buf))
            print_login (utmp_buf);
          else if (need_deadprocs && UT_TYPE_DEAD_PROCESS (utmp_buf))
            print_deadprocs (utmp_buf);
        }
      if (UT_TYPE_BOOT_TIME (utmp_buf))
        boottime = UT_TIME_MEMBER (utmp_buf);
      utmp_buf++;
    }
}
static void who (char const *filename, int options)
{
  size_t n_users;
  STRUCT_UTMP *utmp_buf;
  if (read_utmp (filename, &n_users, &utmp_buf, options) != 0)
    die (EXIT_FAILURE, errno, "%s", quotef (filename));
  if (short_list)
    list_entries_who (n_users, utmp_buf);
  else
    scan_entries (n_users, utmp_buf);
  free (utmp_buf);
}
void usage (int status)
{
  if (status != EXIT_SUCCESS)
    emit_try_help ();
  else
    {
      printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
      fputs (_("\
Print information about users who are currently logged in.\n\
"), stdout);
      fputs (_("\
\n\
  -a, --all         same as -b -d --login -p -r -t -T -u\n\
  -b, --boot        time of last system boot\n\
  -d, --dead        print dead processes\n\
  -H, --heading     print line of column headings\n\
"), stdout);
      fputs (_("\
  -l, --login       print system login processes\n\
"), stdout);
      fputs (_("\
      --lookup      attempt to canonicalize hostnames via DNS\n\
  -m                only hostname and user associated with stdin\n\
  -p, --process     print active processes spawned by init\n\
"), stdout);
      fputs (_("\
  -q, --count       all login names and number of users logged on\n\
  -r, --runlevel    print current runlevel\n\
  -s, --short       print only name, line, and time (default)\n\
  -t, --time        print last system clock change\n\
"), stdout);
      fputs (_("\
  -T, -w, --mesg    add user's message status as +, - or ?\n\
  -u, --users       list users logged in\n\
      --message     same as -T\n\
      --writable    same as -T\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (_("\
\n\
If FILE is not specified, use %s.  %s as FILE is common.\n\
If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.\n\
"), UTMP_FILE, WTMP_FILE);
      emit_ancillary_info (PROGRAM_NAME);
    }
  exit (status);
}
int main (int argc, char **argv)
{
  int optc;
  bool assumptions = true;
  initialize_main (&argc, &argv);
  set_program_name (argv[0]);
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);
  atexit (close_stdout);
  while ((optc = getopt_long (argc, argv, "abdlmpqrstuwHT", longopts, NULL)) != -1)
    {
      switch (optc)
        {
        case 'a':
          need_boottime = true;
          need_deadprocs = true;
          need_login = true;
          need_initspawn = true;
          need_runlevel = true;
          need_clockchange = true;
          need_users = true;
          include_mesg = true;
          include_idle = true;
          include_exit = true;
          assumptions = false;
          break;
        case 'b':
          need_boottime = true;
          assumptions = false;
          break;
        case 'd':
          need_deadprocs = true;
          include_idle = true;
          include_exit = true;
          assumptions = false;
          break;
        case 'H':
          include_heading = true;
          break;
        case 'l':
          need_login = true;
          include_idle = true;
          assumptions = false;
          break;
        case 'm':
          my_line_only = true;
          break;
        case 'p':
          need_initspawn = true;
          assumptions = false;
          break;
        case 'q':
          short_list = true;
          break;
        case 'r':
          need_runlevel = true;
          include_idle = true;
          assumptions = false;
          break;
        case 's':
          short_output = true;
          break;
        case 't':
          need_clockchange = true;
          assumptions = false;
          break;
        case 'T':
        case 'w':
          include_mesg = true;
          break;
        case 'u':
          need_users = true;
          include_idle = true;
          assumptions = false;
          break;
        case LOOKUP_OPTION:
          do_lookup = true;
          break;
        case_GETOPT_HELP_CHAR;
        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
        default:
          usage (EXIT_FAILURE);
        }
    }
  if (assumptions)
    {
      need_users = true;
      short_output = true;
    }
  if (include_exit)
    {
      short_output = false;
    }
  if (hard_locale (LC_TIME))
    {
      time_format = "%Y-%m-%d %H:%M";
      time_format_width = 4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2;
    }
  else
    {
      time_format = "%b %e %H:%M";
      time_format_width = 3 + 1 + 2 + 1 + 2 + 1 + 2;
    }
  switch (argc - optind)
    {
    case 2:			
      my_line_only = true;
      FALLTHROUGH;
    case -1:
    case 0:			
      who (UTMP_FILE, READ_UTMP_CHECK_PIDS);
      break;
    case 1:			
      who (argv[optind], 0);
      break;
    default:	
      error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
      usage (EXIT_FAILURE);
    }
  return EXIT_SUCCESS;
}