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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <unistd.h>
#if __LP64__
static void* __bionic_brk;
#else
void* __bionic_brk; // Accidentally exported by the NDK.
#endif
int brk(void* end_data) {
__bionic_brk = __brk(end_data);
if (__bionic_brk < end_data) {
errno = ENOMEM;
return -1;
}
return 0;
}
void* sbrk(ptrdiff_t increment) {
// Initialize __bionic_brk if necessary.
if (__bionic_brk == NULL) {
__bionic_brk = __brk(NULL);
}
// Don't ask the kernel if we already know the answer.
if (increment == 0) {
return __bionic_brk;
}
// Avoid overflow.
uintptr_t old_brk = reinterpret_cast<uintptr_t>(__bionic_brk);
if ((increment > 0 && static_cast<uintptr_t>(increment) > (UINTPTR_MAX - old_brk)) ||
(increment < 0 && static_cast<uintptr_t>(-increment) > old_brk)) {
errno = ENOMEM;
return reinterpret_cast<void*>(-1);
}
void* desired_brk = reinterpret_cast<void*>(old_brk + increment);
__bionic_brk = __brk(desired_brk);
if (__bionic_brk < desired_brk) {
errno = ENOMEM;
return reinterpret_cast<void*>(-1);
}
return reinterpret_cast<void*>(old_brk);
}
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