2 * Copyright (c) 2019 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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35 * As of 500503 the sbrk() system call works. Prior to 500503 the sbrk()
36 * system call returns EOPNOTSUPP and must be emulated by libc, which we
37 * accomplish with some fake_sbrk() assembly that calls into the even older
38 * 'break' system call.
40 * Note that in older kernels sbrk() does not ENOSYS or generate a signal.
41 * It returns -1 and EOPNOTSUPP.
43 * libc generates the normal sbrk() system call where 'sbrk' is a weak
44 * symbol. We override it here.
46 #include "namespace.h"
47 #include <sys/errno.h>
50 #include "un-namespace.h"
52 void *_sbrk(intptr_t incr);
53 void *fake_sbrk(intptr_t incr);
61 if (res == (void *)-1 && errno == EOPNOTSUPP)
62 res = fake_sbrk(incr);