diff options
Diffstat (limited to 'REORG.TODO/misc/sbrk.c')
-rw-r--r-- | REORG.TODO/misc/sbrk.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/REORG.TODO/misc/sbrk.c b/REORG.TODO/misc/sbrk.c new file mode 100644 index 0000000000..965c0ef879 --- /dev/null +++ b/REORG.TODO/misc/sbrk.c @@ -0,0 +1,64 @@ +/* Copyright (C) 1991-2017 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)) + { + __set_errno (ENOMEM); + return (void *) -1; + } + + if (__brk (oldbrk + increment) < 0) + return (void *) -1; + + return oldbrk; +} +libc_hidden_def (__sbrk) +weak_alias (__sbrk, sbrk) |