| /* |
| * 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 defined(__LP64__) |
| staticvoid* __bionic_brk; |
| #else |
| void* __bionic_brk;// Accidentally exported by the NDK. |
| #endif |
| |
| extern"C"void* __brk(void* __addr); |
| |
| int brk(void* end_data){ |
| __bionic_brk= __brk(end_data); |
| if(__bionic_brk< end_data){ |
| errno= ENOMEM; |
| return-1; |
| } |
| return0; |
| } |
| |
| void* sbrk(ptrdiff_t increment){ |
| // Initialize __bionic_brk if necessary. |
| if(__bionic_brk==nullptr){ |
| __bionic_brk= __brk(nullptr); |
| } |
| |
| // 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; |
| returnreinterpret_cast<void*>(-1); |
| } |
| |
| void* desired_brk=reinterpret_cast<void*>(old_brk+ increment); |
| __bionic_brk= __brk(desired_brk); |
| if(__bionic_brk< desired_brk){ |
| errno= ENOMEM; |
| returnreinterpret_cast<void*>(-1); |
| } |
| |
| returnreinterpret_cast<void*>(old_brk); |
| } |
