1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/* Copyright (C) 2020-2021 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
<https://www.gnu.org/licenses/>. */
#include <sys/types.h>
#include <sys/mman.h>
#include <errno.h>
#include <stdarg.h>
#include <hurd.h>
#include <stdio.h>
/* Remap pages mapped by the range [ADDR,ADDR+OLD_LEN) to new length
NEW_LEN. If MREMAP_MAYMOVE is set in FLAGS the returned address
may differ from ADDR. If MREMAP_FIXED is set in FLAGS the function
takes another parameter which is a fixed address at which the block
resides after a successful call. */
void *
__mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
{
error_t err;
vm_address_t vm_addr = (vm_address_t) addr;
vm_offset_t new_vm_addr = 0;
vm_address_t begin = vm_addr;
vm_address_t end;
vm_size_t len;
vm_prot_t prot;
vm_prot_t max_prot;
vm_inherit_t inherit;
boolean_t shared;
memory_object_name_t obj;
vm_offset_t offset;
if ((flags & ~(MREMAP_MAYMOVE | MREMAP_FIXED)) ||
((flags & MREMAP_FIXED) && !(flags & MREMAP_MAYMOVE)) ||
(old_len == 0 && !(flags & MREMAP_MAYMOVE)))
return (void *) (long int) __hurd_fail (EINVAL);
if (flags & MREMAP_FIXED)
{
va_list arg;
va_start (arg, flags);
new_vm_addr = (vm_offset_t) va_arg (arg, void *);
va_end (arg);
}
err = __vm_region (__mach_task_self (),
&begin, &len, &prot, &max_prot, &inherit,
&shared, &obj, &offset);
if (err)
return (void *) (uintptr_t) __hurd_fail (err);
if (begin > vm_addr)
{
err = EFAULT;
goto out;
}
if (begin < vm_addr || (old_len != 0 && old_len != len))
{
err = EINVAL;
goto out;
}
end = begin + len;
if ((flags & MREMAP_FIXED) &&
((new_vm_addr + new_len > vm_addr && new_vm_addr < end)))
{
/* Overlapping is not supported, like in Linux. */
err = EINVAL;
goto out;
}
/* FIXME: locked memory. */
if (old_len != 0 && !(flags & MREMAP_FIXED))
{
/* A mere change of the existing map. */
if (new_len == len)
{
new_vm_addr = vm_addr;
goto out;
}
if (new_len < len)
{
/* Shrink. */
__mach_port_deallocate (__mach_task_self (), obj);
err = __vm_deallocate (__mach_task_self (),
begin + new_len, len - new_len);
new_vm_addr = vm_addr;
goto out;
}
/* Try to expand. */
err = __vm_map (__mach_task_self (),
&end, new_len - len, 0, 0,
obj, offset + len, 0, prot, max_prot, inherit);
if (!err)
{
/* Ok, that worked. Now coalesce them. */
new_vm_addr = vm_addr;
/* XXX this is not atomic as it is in unix! */
err = __vm_deallocate (__mach_task_self (), begin, new_len);
if (err)
{
__vm_deallocate (__mach_task_self (), end, new_len - len);
goto out;
}
err = __vm_map (__mach_task_self (),
&begin, new_len, 0, 0,
obj, offset, 0, prot, max_prot, inherit);
if (err)
{
/* Oops, try to remap before reporting. */
__vm_map (__mach_task_self (),
&begin, len, 0, 0,
obj, offset, 0, prot, max_prot, inherit);
}
goto out;
}
}
if (!(flags & MREMAP_MAYMOVE))
{
/* Can not map here */
err = ENOMEM;
goto out;
}
err = __vm_map (__mach_task_self (),
&new_vm_addr, new_len, 0,
new_vm_addr == 0, obj, offset,
old_len == 0, prot, max_prot, inherit);
if (err == KERN_NO_SPACE && (flags & MREMAP_FIXED))
{
/* XXX this is not atomic as it is in unix! */
/* The region is already allocated; deallocate it first. */
err = __vm_deallocate (__mach_task_self (), new_vm_addr, new_len);
if (! err)
err = __vm_map (__mach_task_self (),
&new_vm_addr, new_len, 0,
0, obj, offset,
old_len == 0, prot, max_prot, inherit);
}
if (!err)
/* Alright, can remove old mapping. */
__vm_deallocate (__mach_task_self (), begin, len);
out:
__mach_port_deallocate (__mach_task_self (), obj);
if (err)
return (void *) (uintptr_t) __hurd_fail (err);
return (void *) new_vm_addr;
}
libc_hidden_def (__mremap)
weak_alias (__mremap, mremap)
|
