summaryrefslogtreecommitdiffhomepage
path: root/compat/shm.cpp
blob: d30f63463c41bbd2260ae96667833755a7d1149f (plain)
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
/* Copyright (c) 2013 Stanislaw Halik <sthalik@misaki.pl>

 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 */

#include "shm.h"

#if defined _WIN32

#include <cstring>
#include <stdio.h>

#include <accctrl.h>
#include <aclapi.h>

#if !defined __WINE__
#   include <QDebug>
#   define warn(...) (qDebug() << __VA_ARGS__)
#else
#   define warn(...)
#endif

shm_wrapper::shm_wrapper(const char* shm_name, const char* mutex_name, int map_size)
{
    if (mutex_name == nullptr)
        mutex = nullptr;
    else
    {
        mutex = CreateMutexA(nullptr, false, mutex_name);

        if (!mutex)
        {
            warn("CreateMutexA:" << (int) GetLastError());
            return;
        }
    }

    mapped_file = CreateFileMappingA(
                 INVALID_HANDLE_VALUE,
                 nullptr,
                 PAGE_READWRITE,
                 0,
                 map_size,
                 shm_name);

    if (!mapped_file)
    {
        warn("CreateFileMappingA:" << (int) GetLastError());

        return;
    }

    mem = MapViewOfFile(mapped_file,
                        FILE_MAP_WRITE,
                        0,
                        0,
                        map_size);

    if (!mem)
        warn("MapViewOfFile:" << (int) GetLastError());
}

shm_wrapper::~shm_wrapper()
{
    if(mem && !UnmapViewOfFile(mem))
        goto fail;

    if (!CloseHandle(mapped_file))
        goto fail;

    if (mutex && !CloseHandle(mutex))
        goto fail;

    return;

fail:
    (void)0;
#if !defined __WINE__
    qDebug() << "failed to close mapping";
#endif
}

bool shm_wrapper::lock()
{
    if (mutex)
        return WaitForSingleObject(mutex, INFINITE) == WAIT_OBJECT_0;
    else
        return false;
}

bool shm_wrapper::unlock()
{
    if (mutex)
        return ReleaseMutex(mutex);
    else
        return false;
}
#else

#include <limits.h>

#pragma GCC diagnostic ignored "-Wunused-result"
shm_wrapper::shm_wrapper(const char *shm_name, const char* /*mutex_name*/, int map_size) : size(map_size)
{
    char filename[PATH_MAX+2] {};
    strcpy(filename, "/");
    strcat(filename, shm_name);
    fd = shm_open(filename, O_RDWR | O_CREAT, 0600);
    (void) ftruncate(fd, map_size);
    mem = mmap(NULL, map_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, (off_t)0);
}

shm_wrapper::~shm_wrapper()
{
    (void) munmap(mem, size);
    (void) close(fd);
}

bool shm_wrapper::lock()
{
    return flock(fd, LOCK_EX) == 0;
}

bool shm_wrapper::unlock()
{
    return flock(fd, LOCK_UN) == 0;
}
#endif

bool shm_wrapper::success()
{
#ifndef _WIN32
    return mem != (void*) -1;
#else
    return mem != NULL;
#endif
}