87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
/* Determine the protection of a virtual memory area.
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Copyright (C) 2024 Free Software Foundation, Inc.
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This file 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
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by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2024. */
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#include <config.h>
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/* Specification. */
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#include "vma-prot.h"
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#include <stdint.h>
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struct locals
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{
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/* The common protections seen so far. */
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unsigned int prot_so_far;
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/* The remaining address interval.
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remaining_start <= remaining_end-1. */
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uintptr_t remaining_start;
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uintptr_t remaining_end;
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};
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static int
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callback (void *data, uintptr_t start, uintptr_t end, unsigned int flags)
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{
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struct locals *l = (struct locals *) data;
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if (start > l->remaining_start)
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{
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/* The interval [remaining_start, min (remaining_end, start)) is
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unmapped. */
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l->prot_so_far = 0;
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return 1;
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}
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if (end - 1 < l->remaining_start)
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/* The interval [start,end) lies before [remaining_start,remaining_end). */
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return 0;
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/* Here start <= remaining_start <= remaining_end-1
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and remaining_start <= end-1,
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hence start <= remaining_start <= min (end-1, remaining_end-1).
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So, the two intervals intersect. */
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l->prot_so_far &= flags;
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if (l->prot_so_far == 0)
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return 1;
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if (l->remaining_end - 1 <= end - 1)
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/* Done. */
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return 1;
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/* Trim the remaining address interval. */
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l->remaining_start = end;
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return 0;
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}
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int
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get_vma_prot (void *start, size_t size)
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{
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uintptr_t start_address = (uintptr_t) start;
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struct locals l;
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l.prot_so_far = VMA_PROT_READ | VMA_PROT_WRITE | VMA_PROT_EXECUTE;
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l.remaining_start = start_address;
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l.remaining_end = start_address + size;
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if (l.remaining_end < l.remaining_start)
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/* Invalid arguments. */
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return -1;
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if (l.remaining_end > l.remaining_start)
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{
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if (vma_iterate (callback, &l) < 0)
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return -1;
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}
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return l.prot_so_far;
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}
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