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Diffstat (limited to 'REORG.TODO/sysdeps/mach/hurd/check_fds.c')
-rw-r--r--REORG.TODO/sysdeps/mach/hurd/check_fds.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/mach/hurd/check_fds.c b/REORG.TODO/sysdeps/mach/hurd/check_fds.c
new file mode 100644
index 0000000000..69dc11e257
--- /dev/null
+++ b/REORG.TODO/sysdeps/mach/hurd/check_fds.c
@@ -0,0 +1,107 @@
+/* Copyright (C) 2000-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <fcntl.h>
+#include <paths.h>
+#include <unistd.h>
+
+#include <hurd.h>
+#include <hurd/fd.h>
+
+#include <set-hooks.h>
+
+/* Try to get a machine dependent instruction which will make the
+ program crash. This is used in case everything else fails. */
+#include <abort-instr.h>
+#ifndef ABORT_INSTRUCTION
+/* No such instruction is available. */
+# define ABORT_INSTRUCTION
+#endif
+
+static void
+check_one_fd (int fd, int mode)
+{
+ struct hurd_fd *d;
+
+ d = _hurd_fd_get (fd);
+ if (d == NULL)
+ {
+ /* This descriptor hasn't been opened. We try to allocate the
+ descriptor and open /dev/null on it so that the SUID program
+ we are about to start does not accidentally use this
+ descriptor. */
+ d = _hurd_alloc_fd (NULL, fd);
+ if (d != NULL)
+ {
+ mach_port_t port;
+
+ port = __file_name_lookup (_PATH_DEVNULL, mode, 0);
+ if (port)
+ {
+ /* Since /dev/null isn't supposed to be a terminal, we
+ avoid any ctty magic. */
+ d->port.port = port;
+ d->flags = 0;
+
+ __spin_unlock (&d->port.lock);
+ return;
+ }
+ }
+
+ /* We cannot even give an error message here since it would run
+ into the same problems. */
+ while (1)
+ /* Try for ever and ever. */
+ ABORT_INSTRUCTION;
+ }
+}
+
+static void
+check_standard_fds (void)
+{
+ /* Check all three standard file descriptors. */
+ check_one_fd (STDIN_FILENO, O_RDONLY);
+ check_one_fd (STDOUT_FILENO, O_RDWR);
+ check_one_fd (STDERR_FILENO, O_RDWR);
+}
+
+static void
+init_standard_fds (void)
+{
+ /* Now that we have FDs, make sure that, if this is a SUID program,
+ FDs 0, 1 and 2 are allocated. If necessary we'll set them up
+ ourselves. If that's not possible we stop the program. */
+ if (__builtin_expect (__libc_enable_secure, 0))
+ check_standard_fds ();
+
+ (void) &init_standard_fds; /* Avoid "defined but not used" warning. */
+}
+text_set_element (_hurd_fd_subinit, init_standard_fds);
+
+
+#ifndef SHARED
+void
+__libc_check_standard_fds (void)
+{
+ /* We don't check the standard file descriptors here. They will be
+ checked when we initialize the file descriptor table, as part of
+ the _hurd_fd_subinit hook.
+
+ This function is only present to make sure that this module gets
+ linked in when part of the static libc. */
+}
+#endif