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04277e02 | 1 | /* Copyright (C) 1991-2019 Free Software Foundation, Inc. |
478b92f0 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
478b92f0 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
28f540f4 | 8 | |
478b92f0 UD |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 | 17 | |
683158e0 | 18 | #include <errno.h> |
1fdd89a7 UD |
19 | #include <stdint.h> |
20 | #include <unistd.h> | |
54e4b8f2 | 21 | #include <libc-internal.h> |
28f540f4 RM |
22 | |
23 | /* Defined in brk.c. */ | |
683158e0 RM |
24 | extern void *__curbrk; |
25 | extern int __brk (void *addr); | |
28f540f4 RM |
26 | |
27 | /* Extend the process's data space by INCREMENT. | |
28 | If INCREMENT is negative, shrink data space by - INCREMENT. | |
29 | Return start of new space allocated, or -1 for errors. */ | |
683158e0 | 30 | void * |
0ed99ce4 | 31 | __sbrk (intptr_t increment) |
28f540f4 | 32 | { |
683158e0 RM |
33 | void *oldbrk; |
34 | ||
a8874ead UD |
35 | /* If this is not part of the dynamic library or the library is used |
36 | via dynamic loading in a statically linked program update | |
37 | __curbrk from the kernel's brk value. That way two separate | |
38 | instances of __brk and __sbrk can share the heap, returning | |
39 | interleaved pieces of it. */ | |
39778c6c | 40 | if (__curbrk == NULL || __libc_multiple_libcs) |
14bab8de UD |
41 | if (__brk (0) < 0) /* Initialize the break. */ |
42 | return (void *) -1; | |
28f540f4 RM |
43 | |
44 | if (increment == 0) | |
45 | return __curbrk; | |
46 | ||
47 | oldbrk = __curbrk; | |
c13e0783 CH |
48 | if (increment > 0 |
49 | ? ((uintptr_t) oldbrk + (uintptr_t) increment < (uintptr_t) oldbrk) | |
50 | : ((uintptr_t) oldbrk < (uintptr_t) -increment)) | |
51 | { | |
52 | __set_errno (ENOMEM); | |
53 | return (void *) -1; | |
54 | } | |
55 | ||
56 | if (__brk (oldbrk + increment) < 0) | |
683158e0 | 57 | return (void *) -1; |
28f540f4 RM |
58 | |
59 | return oldbrk; | |
60 | } | |
37ba7d66 | 61 | libc_hidden_def (__sbrk) |
28f540f4 | 62 | weak_alias (__sbrk, sbrk) |