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https://git.savannah.gnu.org/git/inetutils.git
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100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
/* readutmp - Basic test of existing utmp/utmpx access.
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Copyright (C) 2010-2025 Free Software Foundation, Inc.
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This file is part of GNU Inetutils.
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GNU Inetutils is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at
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your option) any later version.
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GNU Inetutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see `http://www.gnu.org/licenses/'. */
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/* Written by Mats Erik Andersson. */
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/* Readutmp reads the system's standard UTMP or UTMPX file
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* and verifies that a specific user is logged in.
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*
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* Invocation:
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*
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* readutmp
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* readutmp name
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*
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* The first mode investigates the present user.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <pwd.h>
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#include <progname.h>
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#include <readutmp.h>
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#include <xalloc.h>
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int
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main (int argc, char *argv[])
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{
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#ifndef HAVE_GETUTXUSER
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STRUCT_UTMP *utmpp, *uptr;
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size_t count;
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#endif
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struct passwd *pw;
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char *name;
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int found = 0;
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set_program_name (argv[0]);
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if (argc > 1)
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pw = getpwnam (argv[1]);
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else
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pw = getpwuid (getuid ());
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if (pw)
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name = xstrdup (pw->pw_name);
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else
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{
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fprintf (stderr, "Unknown user '%s'.\n",
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(argc > 1) ? argv[1] : "my own UID");
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return EXIT_FAILURE;
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}
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#ifdef HAVE_GETUTXUSER
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setutxent ();
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found = (getutxuser (name) != 0);
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endutxent ();
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#else /* !HAVE_GETUTXUSER */
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if (read_utmp (UTMP_FILE, &count, &utmpp,
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READ_UTMP_USER_PROCESS | READ_UTMP_CHECK_PIDS))
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{
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perror ("read_utmp");
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return EXIT_FAILURE;
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}
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for (uptr = utmpp; uptr < utmpp + count; uptr++)
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if (!strncmp (name, UT_USER (uptr), sizeof (UT_USER (uptr))))
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{
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found = 1;
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break;
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}
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free (utmpp);
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#endif /* HAVE_GETUTXUSER */
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if (found)
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return EXIT_SUCCESS;
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fprintf (stderr, "User '%s' is not logged in.\n", name);
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return EXIT_FAILURE;
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}
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