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
|
// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef GVISOR_TEST_UTIL_MEMORY_UTIL_H_
#define GVISOR_TEST_UTIL_MEMORY_UTIL_H_
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/mman.h>
#include "absl/strings/str_format.h"
#include "absl/strings/string_view.h"
#include "test/util/logging.h"
#include "test/util/posix_error.h"
#include "test/util/save_util.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
// RAII type for mmap'ed memory. Only usable in tests due to use of a test-only
// macro that can't be named without invoking the presubmit's wrath.
class Mapping {
public:
// Constructs a mapping that owns nothing.
Mapping() = default;
// Constructs a mapping that owns the mmapped memory [ptr, ptr+len). Most
// users should use Mmap or MmapAnon instead.
Mapping(void* ptr, size_t len) : ptr_(ptr), len_(len) {}
Mapping(Mapping&& orig) : ptr_(orig.ptr_), len_(orig.len_) { orig.release(); }
Mapping& operator=(Mapping&& orig) {
ptr_ = orig.ptr_;
len_ = orig.len_;
orig.release();
return *this;
}
Mapping(Mapping const&) = delete;
Mapping& operator=(Mapping const&) = delete;
~Mapping() { reset(); }
void* ptr() const { return ptr_; }
size_t len() const { return len_; }
// Returns a pointer to the end of the mapping. Useful for when the mapping
// is used as a thread stack.
void* endptr() const { return reinterpret_cast<void*>(addr() + len_); }
// Returns the start of this mapping cast to uintptr_t for ease of pointer
// arithmetic.
uintptr_t addr() const { return reinterpret_cast<uintptr_t>(ptr_); }
// Returns the end of this mapping cast to uintptr_t for ease of pointer
// arithmetic.
uintptr_t endaddr() const { return reinterpret_cast<uintptr_t>(endptr()); }
// Returns this mapping as a StringPiece for ease of comparison.
//
// This function is named view in anticipation of the eventual replacement of
// StringPiece with std::string_view.
absl::string_view view() const {
return absl::string_view(static_cast<char const*>(ptr_), len_);
}
// These are both named reset for consistency with standard smart pointers.
void reset(void* ptr, size_t len) {
if (len_) {
TEST_PCHECK(munmap(ptr_, len_) == 0);
}
ptr_ = ptr;
len_ = len;
}
void reset() { reset(nullptr, 0); }
void release() {
ptr_ = nullptr;
len_ = 0;
}
private:
void* ptr_ = nullptr;
size_t len_ = 0;
};
// Wrapper around mmap(2) that returns a Mapping.
inline PosixErrorOr<Mapping> Mmap(void* addr, size_t length, int prot,
int flags, int fd, off_t offset) {
void* ptr = mmap(addr, length, prot, flags, fd, offset);
if (ptr == MAP_FAILED) {
return PosixError(
errno, absl::StrFormat("mmap(%p, %d, %x, %x, %d, %d)", addr, length,
prot, flags, fd, offset));
}
MaybeSave();
return Mapping(ptr, length);
}
// Convenience wrapper around Mmap for anonymous mappings.
inline PosixErrorOr<Mapping> MmapAnon(size_t length, int prot, int flags) {
return Mmap(nullptr, length, prot, flags | MAP_ANONYMOUS, -1, 0);
}
// Wrapper for mremap that returns a PosixErrorOr<>, since the return type of
// void* isn't directly compatible with SyscallSucceeds.
inline PosixErrorOr<void*> Mremap(void* old_address, size_t old_size,
size_t new_size, int flags,
void* new_address) {
void* rv = mremap(old_address, old_size, new_size, flags, new_address);
if (rv == MAP_FAILED) {
return PosixError(errno, "mremap failed");
}
return rv;
}
// Returns true if the page containing addr is mapped.
inline bool IsMapped(uintptr_t addr) {
int const rv = msync(reinterpret_cast<void*>(addr & ~(kPageSize - 1)),
kPageSize, MS_ASYNC);
if (rv == 0) {
return true;
}
TEST_PCHECK_MSG(errno == ENOMEM, "msync failed with unexpected errno");
return false;
}
} // namespace testing
} // namespace gvisor
#endif // GVISOR_TEST_UTIL_MEMORY_UTIL_H_
|
