--- /dev/null
+/* pt_chown - helper program for `grantpt'.
+ Copyright (C) 1998, 1999, 2009, 2010 Free Software Foundation, Inc.
+ Contributed by C. Scott Ananian <cananian@alumni.princeton.edu>, 1998.
+
+ 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/>. */
+
+#include <config.h>
+
+#include <errno.h>
+#include <grp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "idpriv.h"
+#include "pty-private.h"
+
+/* For security reasons, we try to minimize the dependencies on libraries
+ outside libc. This means, in particular:
+ - No use of gettext(), since it's usually implemented in libintl.
+ - No use of error() or argp, since they rely on gettext by default. */
+
+
+static int
+do_pt_chown (void)
+{
+ char *pty;
+ struct stat st;
+ struct group *p;
+ gid_t gid;
+
+ /* Check that PTY_FILENO is a valid master pseudo terminal. */
+ pty = ptsname (PTY_FILENO);
+ if (pty == NULL)
+ return errno == EBADF ? FAIL_EBADF : FAIL_EINVAL;
+
+ /* Check that the returned slave pseudo terminal is a
+ character device. */
+ if (stat (pty, &st) < 0 || !S_ISCHR (st.st_mode))
+ return FAIL_EINVAL;
+
+ /* Get the group ID of the special `tty' group. */
+ p = getgrnam (TTY_GROUP);
+ gid = p ? p->gr_gid : getgid ();
+
+ /* Set the owner to the real user ID, and the group to that special
+ group ID. */
+ if (st.st_gid != gid && chown (pty, getuid (), gid) < 0)
+ return FAIL_EACCES;
+
+ /* Set the permission mode to readable and writable by the owner,
+ and writable by the group. */
+ if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != (S_IRUSR|S_IWUSR|S_IWGRP)
+ && chmod (pty, S_IRUSR|S_IWUSR|S_IWGRP) < 0)
+ return FAIL_EACCES;
+
+ return 0;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+ uid_t euid = geteuid ();
+
+ if (argc == 1 && euid == 0)
+ {
+ /* Normal invocation of this program is with no arguments and
+ with privileges. */
+ return do_pt_chown ();
+ }
+
+ /* We aren't going to be using privileges, so drop them right now. */
+ if (idpriv_drop () < 0)
+ return EXIT_FAILURE;
+
+ {
+ int do_help = 0;
+ int do_version = 0;
+ int remaining;
+
+ for (remaining = 1; remaining < argc; remaining++)
+ {
+ const char *arg = argv[remaining];
+
+ if (arg[0] == '-')
+ {
+ if (strcmp (arg, "--") == 0)
+ {
+ remaining++;
+ break;
+ }
+ else if (strcmp (arg, "--help") == 0)
+ do_help = 1;
+ else if (strcmp (arg, "--version") == 0)
+ do_version = 1;
+ else
+ {
+ fprintf (stderr, "pt_chown: invalid option: %s\n", arg);
+ return EXIT_FAILURE;
+ }
+ }
+ else
+ break;
+ }
+
+ if (remaining < argc)
+ {
+ fprintf (stderr, "pt_chown: too many arguments\n");
+ return EXIT_FAILURE;
+ }
+
+ if (do_help)
+ {
+ printf ("Usage: pt_chown [OPTION...]\n");
+ printf ("Set the owner, group and access permission of the slave pseudo terminal\n"
+ "corresponding to the master pseudo terminal passed on file descriptor %d.\n"
+ "This is the helper program for the 'grantpt' function. It is not intended\n"
+ "to be run directly from the command line.\n",
+ PTY_FILENO);
+ printf ("\n");
+ printf (" --help Give this help list\n");
+ printf (" --version Print program version\n");
+ printf ("\n");
+ printf ("The owner is set to the current user, the group is set to '%s', and the\n"
+ "access permission is set to '%o'.\n",
+ TTY_GROUP, S_IRUSR|S_IWUSR|S_IWGRP);
+ printf ("Please report bugs to <bug-gnulib@gnu.org>.\n");
+ return EXIT_SUCCESS;
+ }
+
+ if (do_version)
+ {
+ printf ("pt_chown (GNU %s) %s\n", "libc", "2.11");
+ printf ("Copyright (C) %s Free Software Foundation, Inc.\n"
+ "This is free software; see the source for copying conditions. There is NO\n"
+ "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
+ "1999");
+ return EXIT_SUCCESS;
+ }
+ }
+
+ /* Check if we are properly installed. */
+ if (euid != 0)
+ {
+ fprintf (stderr, "pt_chown: needs to be installed setuid 'root'\n");
+ return FAIL_EXEC;
+ }
+
+ return EXIT_SUCCESS;
+}
--- /dev/null
+/* Interface to the pt_chown program.
+ Copyright (C) 1998, 1999, 2009, 2010 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _PTY_PRIVATE_H
+#define _PTY_PRIVATE_H 1
+
+/* The group slave pseudo terminals belong to. */
+#define TTY_GROUP "tty"
+
+/* The file descriptor connected to the master pseudo terminal. */
+#define PTY_FILENO 3
+
+/* Path to the helper program that implements `grantpt' in user space. */
+#define _PATH_PT_CHOWN PKGLIBEXECDIR "/pt_chown"
+
+/* Test whether given TTY is really a Unix98 pseudo terminal. */
+/* #define unix98_pseudo_p(Dev) ... */
+
+/* Exit codes for the helper program. */
+enum /* failure modes */
+{
+ FAIL_EBADF = 1,
+ FAIL_EINVAL,
+ FAIL_EACCES,
+ FAIL_EXEC,
+ FAIL_ENOMEM
+};
+
+#endif /* pty-private.h */
projects / gnulib.git / commitdiff