summaryrefslogtreecommitdiffhomepage
path: root/opentrack-compat/shm.cpp
blob: 55aa7a4158194ef8915becbde7a9d370e3faa1bb (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
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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
/* Copyright (c) 2013 Stanisław 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>

struct secattr
{
    bool success;
    SECURITY_DESCRIPTOR* pSD;
    SECURITY_ATTRIBUTES attrs;
    PSID pEveryoneSID;
    PACL pACL;

    void cleanup()
    {
        if (pEveryoneSID)
            FreeSid(pEveryoneSID);
        if (pACL)
            LocalFree(pACL);
        if (pSD)
            LocalFree(pSD);
        success = false;
        pSD = nullptr;
        pEveryoneSID = nullptr;
        pACL = nullptr;
    }

    secattr(DWORD perms) : success(true), pSD(nullptr), pEveryoneSID(nullptr), pACL(nullptr)
    {
        SID_IDENTIFIER_AUTHORITY SIDAuthWorld = SECURITY_WORLD_SID_AUTHORITY;
        EXPLICIT_ACCESS ea;

        if(!AllocateAndInitializeSid(&SIDAuthWorld, 1,
                         SECURITY_WORLD_RID,
                         0, 0, 0, 0, 0, 0, 0,
                         &pEveryoneSID))
        {
            fprintf(stderr, "AllocateAndInitializeSid: %d\n", (int) GetLastError());
            goto cleanup;
        }

        memset(&ea, 0, sizeof(ea));

        ea.grfAccessPermissions = perms;
        ea.grfAccessMode = SET_ACCESS;
        ea.grfInheritance = NO_INHERITANCE;
        ea.Trustee.TrusteeForm = TRUSTEE_IS_SID;
        ea.Trustee.TrusteeType = TRUSTEE_IS_WELL_KNOWN_GROUP;
        ea.Trustee.ptstrName  = (LPTSTR) pEveryoneSID;

        if (SetEntriesInAcl(1, &ea, NULL, &pACL) != ERROR_SUCCESS)
        {
            fprintf(stderr, "SetEntriesInAcl: %d\n", (int) GetLastError());
            goto cleanup;
        }

        pSD = (SECURITY_DESCRIPTOR*) LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
        if (pSD == nullptr)
        {
            fprintf(stderr, "LocalAlloc: %d\n", (int) GetLastError());
            goto cleanup;
        }

        if (!InitializeSecurityDescriptor(pSD,
                    SECURITY_DESCRIPTOR_REVISION))
        {
            fprintf(stderr, "InitializeSecurityDescriptor: %d\n", (int) GetLastError());
            goto cleanup;
        }

        if (!SetSecurityDescriptorDacl(pSD,
                                       TRUE,
                                       pACL,
                                       FALSE))
        {
            fprintf(stderr, "SetSecurityDescriptorDacl: %d\n", (int) GetLastError());
            goto cleanup;
        }

        attrs.bInheritHandle = false;
        attrs.lpSecurityDescriptor = pSD;
        attrs.nLength = sizeof(SECURITY_ATTRIBUTES);

        fflush(stderr);

        return;
cleanup:
        fflush(stderr);
        cleanup();
    }

    ~secattr()
    {
        cleanup();
    }
};

PortableLockedShm::PortableLockedShm(const char* shmName, const char* mutexName, int mapSize)
{
    secattr sa(GENERIC_ALL|SYNCHRONIZE);

    hMutex = CreateMutexA(sa.success ? &sa.attrs : nullptr, false, mutexName);
    if (!hMutex)
    {
        fprintf(stderr, "CreateMutexA: %d\n", (int) GetLastError());
        fflush(stderr);
    }
    hMapFile = CreateFileMappingA(
                 INVALID_HANDLE_VALUE,
                 sa.success ? &sa.attrs : nullptr,
                 PAGE_READWRITE,
                 0,
                 mapSize,
                 shmName);
    if (!hMapFile)
    {
        fprintf(stderr, "CreateFileMappingA: %d\n", (int) GetLastError());
        fflush(stderr);
    }
    mem = MapViewOfFile(hMapFile,
                        FILE_MAP_WRITE,
                        0,
                        0,
                        mapSize);
    if (!mem)
    {
        fprintf(stderr, "MapViewOfFile: %d\n", (int) GetLastError());
        fflush(stderr);
    }
}

PortableLockedShm::~PortableLockedShm()
{
    UnmapViewOfFile(mem);
    CloseHandle(hMapFile);
    CloseHandle(hMutex);
}

void PortableLockedShm::lock()
{
    (void) WaitForSingleObject(hMutex, INFINITE);
}

void PortableLockedShm::unlock()
{
    (void) ReleaseMutex(hMutex);
}
#else

#include <limits.h>

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

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

void PortableLockedShm::lock()
{
    flock(fd, LOCK_EX);
}

void PortableLockedShm::unlock()
{
    flock(fd, LOCK_UN);
}
#endif

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