mirror of
https://https.git.savannah.gnu.org/git/bash.git
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Chet Ramey
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
/* Copyright (C) 2023-2024 Free Software Foundation, Inc.
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This file is part of GNU Bash, the Bourne Again SHell.
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Bash 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
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(at your option) any later version.
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Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <unistd.h>
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#include <errno.h>
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#if defined (HAVE_BRK) && !defined (HAVE_SBRK)
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static void *initialbrk;
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static void *curbrk;
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static int
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initbrk (void)
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{
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if (initialbrk == 0)
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{
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void *b;
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b = brk (NULL);
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if (b == (void *)-1)
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return -1;
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initialbrk = curbrk = b;
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}
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return (0);
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}
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/* sbrk(3) implementation in terms of brk(2). Good enough for malloc to use. */
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void *
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sbrk (intptr_t incr)
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{
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void *newbrk, *oldbrk;
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if (initialbrk == 0 && initbrk () == -1)
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{
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errno = ENOMEM;
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return (void *)-1;
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}
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if (incr == 0)
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return curbrk;
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/* bounds checking, overflow */
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if ((incr > 0 && (uintptr_t) curbrk + incr < (uintptr_t) curbrk) ||
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(incr < 0 && (uintptr_t) curbrk + incr > (uintptr_t) curbrk))
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{
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errno = ENOMEM;
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return (void *)-1;
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}
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newbrk = curbrk + incr;
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if (newbrk < initialbrk)
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{
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errno = EINVAL;
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return (void *)-1;
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}
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if (brk (newbrk) == (void *)-1)
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return (void *)-1; /* preserve errno */
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oldbrk = curbrk;
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curbrk = newbrk;
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return (oldbrk);
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}
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#endif /* HAVE_BRK && !HAVE_SBRK */
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