1 /* Copyright (C) 2000 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library 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 GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26 #include <set-hooks.h>
28 /* Try to get a machine dependent instruction which will make the
29 program crash. This is used in case everything else fails. */
30 #include <abort-instr.h>
31 #ifndef ABORT_INSTRUCTION
32 /* No such instruction is available. */
33 # define ABORT_INSTRUCTION
37 check_one_fd (int fd, int mode)
41 d = _hurd_fd_get (fd);
44 /* This descriptor hasn't been opened. We try to allocate the
45 descriptor and open /dev/null on it so that the SUID program
46 we are about to start does not accidently use this
48 d = _hurd_alloc_fd (NULL, fd);
53 port = __file_name_lookup (_PATH_DEVNULL, mode, 0);
56 /* Since /dev/null isn't supposed to be a terminal, we
57 avoid any ctty magic. */
61 __spin_unlock (&d->port.lock);
66 /* We cannot even give an error message here since it would run
67 into the same problems. */
69 /* Try for ever and ever. */
75 check_standard_fds (void)
77 /* Check all three standard file descriptors. */
78 check_one_fd (STDIN_FILENO, O_RDONLY);
79 check_one_fd (STDOUT_FILENO, O_RDWR);
80 check_one_fd (STDERR_FILENO, O_RDWR);
84 init_standard_fds (void)
86 /* Now that we have FDs, make sure that, if this is a SUID program,
87 FDs 0, 1 and 2 are allocated. If necessary we'll set them up
88 ourselves. If that's not possible we stop the program. */
89 if (__builtin_expect (__libc_enable_secure, 0))
90 check_standard_fds ();
92 (void) &init_standard_fds; /* Avoid "defined but not used" warning. */
94 text_set_element (_hurd_fd_subinit, init_standard_fds);
99 __libc_check_standard_fds (void)
101 /* We don't check the standard file descriptors here. They will be
102 checked when we initialize the file descriptor table, as part of
103 the _hurd_fd_subinit hook.
105 This function is only present to make sure that this module gets
106 linked in when part of the static libc. */