533dde4dbf
Note that the kernel returns the current break on error or if the requested break is smaller than the minimum break, or the new break. I don't know where we got the idea that the kernel could return -1. Also optimizes the query case. Also hides an accidentally-exported symbol for LP64. Change-Id: I0fd6b8b14ddf1ae82935c0c3fc610da5cc74932e
75 lines
2.4 KiB
C++
75 lines
2.4 KiB
C++
/*
|
|
* 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.
|
|
intptr_t old_brk = reinterpret_cast<intptr_t>(__bionic_brk);
|
|
if ((increment > 0 && INTPTR_MAX - increment > old_brk) ||
|
|
(increment < 0 && (increment == PTRDIFF_MIN || old_brk < -increment))) {
|
|
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);
|
|
}
|