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Update some other copyright years automatically, by running: Run 'UPDATE_COPYRIGHT_YEAR=2019 \ UPDATE_COPYRIGHT_USE_INTERVALS=1 \ UPDATE_COPYRIGHT_MAX_LINE_LENGTH=79 admin/update-copyright' followed by 'admin/merge-gnulib'.
79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
/* Pointer bounds checking for GNU Emacs
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Copyright 2017-2019 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs 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 Emacs is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU 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 GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
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/* Pointer bounds checking is a no-op unless running on hardware
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supporting Intel MPX (Intel Skylake or better). Also, it requires
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GCC 5 and Linux kernel 3.19, or later. Configure with
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CFLAGS='-fcheck-pointer-bounds -mmpx', perhaps with
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-fchkp-first-field-has-own-bounds thrown in.
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Although pointer bounds checking can help during debugging, it is
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disabled by default because it hurts performance significantly.
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The checking does not detect all pointer errors. For example, a
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dumped Emacs might not detect a bounds violation of a pointer that
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was created before Emacs was dumped. */
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#ifndef PTR_BOUNDS_H
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#define PTR_BOUNDS_H
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#include <stddef.h>
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/* When not checking pointer bounds, the following macros simply
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return their first argument. These macros return either void *, or
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the same type as their first argument. */
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INLINE_HEADER_BEGIN
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/* Return a copy of P, with bounds narrowed to [P, P + N). */
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#ifdef __CHKP__
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INLINE void *
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ptr_bounds_clip (void const *p, size_t n)
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{
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return __builtin___bnd_narrow_ptr_bounds (p, p, n);
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}
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#else
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# define ptr_bounds_clip(p, n) ((void) (size_t) {n}, p)
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#endif
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/* Return a copy of P, but with the bounds of Q. */
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#ifdef __CHKP__
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# define ptr_bounds_copy(p, q) __builtin___bnd_copy_ptr_bounds (p, q)
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#else
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# define ptr_bounds_copy(p, q) ((void) (void const *) {q}, p)
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#endif
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/* Return a copy of P, but with infinite bounds.
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This is a loophole in pointer bounds checking. */
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#ifdef __CHKP__
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# define ptr_bounds_init(p) __builtin___bnd_init_ptr_bounds (p)
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#else
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# define ptr_bounds_init(p) (p)
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#endif
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/* Return a copy of P, but with bounds [P, P + N).
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This is a loophole in pointer bounds checking. */
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#ifdef __CHKP__
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# define ptr_bounds_set(p, n) __builtin___bnd_set_ptr_bounds (p, n)
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#else
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# define ptr_bounds_set(p, n) ((void) (size_t) {n}, p)
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#endif
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INLINE_HEADER_END
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#endif /* PTR_BOUNDS_H */
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