+
−/* GNU's read utmp module.
+
−
+
−   Copyright (C) 1992-2001, 2003-2006, 2009-2013 Free Software Foundation, Inc.
+
−
+
−   This program is free software: you can redistribute it and/or modify
+
−   it under the terms of the GNU General Public License as published by
+
−   the Free Software Foundation; either version 3 of the License, or
+
−   (at your option) any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
+
−   but WITHOUT ANY WARRANTY; without even the implied warranty of
+
−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+
−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
−
+
−/* Written by jla; revised by djm */
+
−
+
−#include <config.h>
+
−
+
−#include "readutmp.h"
+
−
+
−#include <errno.h>
+
−#include <stdio.h>
+
−
+
−#include <sys/types.h>
+
−#include <sys/stat.h>
+
−#include <signal.h>
+
−#include <stdbool.h>
+
−#include <string.h>
+
−#include <stdlib.h>
+
−#include <stdint.h>
+
−
+
−#include "xalloc.h"
+
−
+
−#if USE_UNLOCKED_IO
+
−# include "unlocked-io.h"
+
−#endif
+
−
+
−/* Copy UT->ut_name into storage obtained from malloc.  Then remove any
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−   trailing spaces from the copy, NUL terminate it, and return the copy.  */
+
−
+
−char *
+
−extract_trimmed_name (const STRUCT_UTMP *ut)
+
−{
+
−  char *p, *trimmed_name;
+
−
+
−  trimmed_name = xmalloc (sizeof (UT_USER (ut)) + 1);
+
−  strncpy (trimmed_name, UT_USER (ut), sizeof (UT_USER (ut)));
+
−  /* Append a trailing NUL.  Some systems pad names shorter than the
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−     maximum with spaces, others pad with NULs.  Remove any trailing
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−     spaces.  */
+
−  trimmed_name[sizeof (UT_USER (ut))] = '\0';
+
−  for (p = trimmed_name + strlen (trimmed_name);
+
−       trimmed_name < p && p[-1] == ' ';
+
−       *--p = '\0')
+
−    continue;
+
−  return trimmed_name;
+
−}
+
−
+
−/* Is the utmp entry U desired by the user who asked for OPTIONS?  */
+
−
+
−static bool
+
−desirable_utmp_entry (STRUCT_UTMP const *u, int options)
+
−{
+
−  bool user_proc = IS_USER_PROCESS (u);
+
−  if ((options & READ_UTMP_USER_PROCESS) && !user_proc)
+
−    return false;
+
−  if ((options & READ_UTMP_CHECK_PIDS)
+
−      && user_proc
+
−      && 0 < UT_PID (u)
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−      && (kill (UT_PID (u), 0) < 0 && errno == ESRCH))
+
−    return false;
+
−  return true;
+
−}
+
−
+
−/* Read the utmp entries corresponding to file FILE into freshly-
+
−   malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to
+
−   the number of entries, and return zero.  If there is any error,
+
−   return -1, setting errno, and don't modify the parameters.
+
−   If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose
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−   process-IDs do not currently exist.  */
+
−
+
−#ifdef UTMP_NAME_FUNCTION
+
−
+
−int
+
−read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
+
−           int options)
+
−{
+
−  size_t n_read = 0;
+
−  size_t n_alloc = 0;
+
−  STRUCT_UTMP *utmp = NULL;
+
−  STRUCT_UTMP *u;
+
−
+
−  /* Ignore the return value for now.
+
−     Solaris' utmpname returns 1 upon success -- which is contrary
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−     to what the GNU libc version does.  In addition, older GNU libc
+
−     versions are actually void.   */
+
−  UTMP_NAME_FUNCTION (file);
+
−
+
−  SET_UTMP_ENT ();
+
−
+
−  while ((u = GET_UTMP_ENT ()) != NULL)
+
−    if (desirable_utmp_entry (u, options))
+
−      {
+
−        if (n_read == n_alloc)
+
−          utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
+
−
+
−        utmp[n_read++] = *u;
+
−      }
+
−
+
−  END_UTMP_ENT ();
+
−
+
−  *n_entries = n_read;
+
−  *utmp_buf = utmp;
+
−
+
−  return 0;
+
−}
+
−
+
−#else
+
−
+
−int
+
−read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
+
−           int options)
+
−{
+
−  size_t n_read = 0;
+
−  size_t n_alloc = 0;
+
−  STRUCT_UTMP *utmp = NULL;
+
−  int saved_errno;
+
−  FILE *f = fopen (file, "r");
+
−
+
−  if (! f)
+
−    return -1;
+
−
+
−  for (;;)
+
−    {
+
−      if (n_read == n_alloc)
+
−        utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
+
−      if (fread (&utmp[n_read], sizeof utmp[n_read], 1, f) == 0)
+
−        break;
+
−      n_read += desirable_utmp_entry (&utmp[n_read], options);
+
−    }
+
−
+
−  saved_errno = ferror (f) ? errno : 0;
+
−  if (fclose (f) != 0)
+
−    saved_errno = errno;
+
−  if (saved_errno != 0)
+
−    {
+
−      free (utmp);
+
−      errno = saved_errno;
+
−      return -1;
+
−    }
+
−
+
−  *n_entries = n_read;
+
−  *utmp_buf = utmp;
+
−
+
−  return 0;
+
−}
+
−
+
−#endif