| /* Copyright (C) 1991-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <stdint.h> |
| #include <unistd.h> |
| |
| /* Defined in brk.c. */ |
| extern void *__curbrk; |
| extern int __brk (void *addr); |
| |
| /* Defined in init-first.c. */ |
| extern int __libc_multiple_libcs attribute_hidden; |
| |
| /* Extend the process's data space by INCREMENT. |
| If INCREMENT is negative, shrink data space by - INCREMENT. |
| Return start of new space allocated, or -1 for errors. */ |
| void * |
| __sbrk (intptr_t increment) |
| { |
| void *oldbrk; |
| |
| /* If this is not part of the dynamic library or the library is used |
| via dynamic loading in a statically linked program update |
| __curbrk from the kernel's brk value. That way two separate |
| instances of __brk and __sbrk can share the heap, returning |
| interleaved pieces of it. */ |
| if (__curbrk == NULL || __libc_multiple_libcs) |
| if (__brk (0) < 0) /* Initialize the break. */ |
| return (void *) -1; |
| |
| if (increment == 0) |
| return __curbrk; |
| |
| oldbrk = __curbrk; |
| if ((increment > 0 |
| ? ((uintptr_t) oldbrk + (uintptr_t) increment < (uintptr_t) oldbrk) |
| : ((uintptr_t) oldbrk < (uintptr_t) -increment)) |
| || __brk (oldbrk + increment) < 0) |
| return (void *) -1; |
| |
| return oldbrk; |
| } |
| libc_hidden_def (__sbrk) |
| weak_alias (__sbrk, sbrk) |
