1*d7847a8dSBrooks Davis /*-
2*d7847a8dSBrooks Davis * SPDX-License-Identifier: BSD-2-Clause
3*d7847a8dSBrooks Davis *
4*d7847a8dSBrooks Davis * Copyright (c) 2018 Mark Johnston <markj@FreeBSD.org>
5*d7847a8dSBrooks Davis *
6*d7847a8dSBrooks Davis * Redistribution and use in source and binary forms, with or without
7*d7847a8dSBrooks Davis * modification, are permitted provided that the following conditions
8*d7847a8dSBrooks Davis * are met:
9*d7847a8dSBrooks Davis * 1. Redistributions of source code must retain the above copyright
10*d7847a8dSBrooks Davis * notice, this list of conditions and the following disclaimer.
11*d7847a8dSBrooks Davis * 2. Redistributions in binary form must reproduce the above copyright
12*d7847a8dSBrooks Davis * notice, this list of conditions and the following disclaimer in the
13*d7847a8dSBrooks Davis * documentation and/or other materials provided with the distribution.
14*d7847a8dSBrooks Davis *
15*d7847a8dSBrooks Davis * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16*d7847a8dSBrooks Davis * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17*d7847a8dSBrooks Davis * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18*d7847a8dSBrooks Davis * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19*d7847a8dSBrooks Davis * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20*d7847a8dSBrooks Davis * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21*d7847a8dSBrooks Davis * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22*d7847a8dSBrooks Davis * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23*d7847a8dSBrooks Davis * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24*d7847a8dSBrooks Davis * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25*d7847a8dSBrooks Davis * SUCH DAMAGE.
26*d7847a8dSBrooks Davis */
27*d7847a8dSBrooks Davis
28*d7847a8dSBrooks Davis #include <sys/types.h>
29*d7847a8dSBrooks Davis #include <sys/syscall.h>
30*d7847a8dSBrooks Davis #include <errno.h>
31*d7847a8dSBrooks Davis #include <stdint.h>
32*d7847a8dSBrooks Davis #include <stdlib.h>
33*d7847a8dSBrooks Davis
34*d7847a8dSBrooks Davis void *__sys_break(char *nsize);
35*d7847a8dSBrooks Davis
36*d7847a8dSBrooks Davis static uintptr_t curbrk, minbrk;
37*d7847a8dSBrooks Davis static int curbrk_initted;
38*d7847a8dSBrooks Davis
39*d7847a8dSBrooks Davis static int
initbrk(void)40*d7847a8dSBrooks Davis initbrk(void)
41*d7847a8dSBrooks Davis {
42*d7847a8dSBrooks Davis void *newbrk;
43*d7847a8dSBrooks Davis
44*d7847a8dSBrooks Davis if (!curbrk_initted) {
45*d7847a8dSBrooks Davis newbrk = __sys_break(NULL);
46*d7847a8dSBrooks Davis if (newbrk == (void *)-1)
47*d7847a8dSBrooks Davis return (-1);
48*d7847a8dSBrooks Davis curbrk = minbrk = (uintptr_t)newbrk;
49*d7847a8dSBrooks Davis curbrk_initted = 1;
50*d7847a8dSBrooks Davis }
51*d7847a8dSBrooks Davis return (0);
52*d7847a8dSBrooks Davis }
53*d7847a8dSBrooks Davis
54*d7847a8dSBrooks Davis static void *
mvbrk(void * addr)55*d7847a8dSBrooks Davis mvbrk(void *addr)
56*d7847a8dSBrooks Davis {
57*d7847a8dSBrooks Davis uintptr_t oldbrk;
58*d7847a8dSBrooks Davis
59*d7847a8dSBrooks Davis if ((uintptr_t)addr < minbrk) {
60*d7847a8dSBrooks Davis /* Emulate legacy error handling in the syscall. */
61*d7847a8dSBrooks Davis errno = EINVAL;
62*d7847a8dSBrooks Davis return ((void *)-1);
63*d7847a8dSBrooks Davis }
64*d7847a8dSBrooks Davis if (__sys_break(addr) == (void *)-1)
65*d7847a8dSBrooks Davis return ((void *)-1);
66*d7847a8dSBrooks Davis oldbrk = curbrk;
67*d7847a8dSBrooks Davis curbrk = (uintptr_t)addr;
68*d7847a8dSBrooks Davis return ((void *)oldbrk);
69*d7847a8dSBrooks Davis }
70*d7847a8dSBrooks Davis
71*d7847a8dSBrooks Davis int
brk(const void * addr)72*d7847a8dSBrooks Davis brk(const void *addr)
73*d7847a8dSBrooks Davis {
74*d7847a8dSBrooks Davis
75*d7847a8dSBrooks Davis if (initbrk() == -1)
76*d7847a8dSBrooks Davis return (-1);
77*d7847a8dSBrooks Davis if ((uintptr_t)addr < minbrk)
78*d7847a8dSBrooks Davis addr = (void *)minbrk;
79*d7847a8dSBrooks Davis return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0);
80*d7847a8dSBrooks Davis }
81*d7847a8dSBrooks Davis
82*d7847a8dSBrooks Davis int
_brk(const void * addr)83*d7847a8dSBrooks Davis _brk(const void *addr)
84*d7847a8dSBrooks Davis {
85*d7847a8dSBrooks Davis
86*d7847a8dSBrooks Davis if (initbrk() == -1)
87*d7847a8dSBrooks Davis return (-1);
88*d7847a8dSBrooks Davis return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0);
89*d7847a8dSBrooks Davis }
90*d7847a8dSBrooks Davis
91*d7847a8dSBrooks Davis void *
sbrk(intptr_t incr)92*d7847a8dSBrooks Davis sbrk(intptr_t incr)
93*d7847a8dSBrooks Davis {
94*d7847a8dSBrooks Davis
95*d7847a8dSBrooks Davis if (initbrk() == -1)
96*d7847a8dSBrooks Davis return ((void *)-1);
97*d7847a8dSBrooks Davis if ((incr > 0 && curbrk + incr < curbrk) ||
98*d7847a8dSBrooks Davis (incr < 0 && curbrk + incr > curbrk)) {
99*d7847a8dSBrooks Davis /* Emulate legacy error handling in the syscall. */
100*d7847a8dSBrooks Davis errno = EINVAL;
101*d7847a8dSBrooks Davis return ((void *)-1);
102*d7847a8dSBrooks Davis }
103*d7847a8dSBrooks Davis return (mvbrk((void *)(curbrk + incr)));
104*d7847a8dSBrooks Davis }
105