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
|
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <errno.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include "base/gfx/size.h"
#include "base/logging.h"
#include "chrome/common/transport_dib.h"
#include "chrome/common/x11_util.h"
// The shmat system call uses this as it's invalid return address
static void *const kInvalidAddress = (void*) -1;
TransportDIB::TransportDIB()
: key_(-1),
address_(kInvalidAddress),
x_shm_(0),
display_(NULL),
size_(0) {
}
TransportDIB::~TransportDIB() {
if (address_ != kInvalidAddress) {
shmdt(address_);
address_ = kInvalidAddress;
}
if (x_shm_) {
DCHECK(display_);
x11_util::DetachSharedMemory(display_, x_shm_);
}
}
// static
TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
// We use a mode of 0666 since the X server won't attach to memory which is
// 0600 since it can't know if it (as a root process) is being asked to map
// someone else's private shared memory region.
const int shmkey = shmget(IPC_PRIVATE, size, 0666);
if (shmkey == -1) {
DLOG(ERROR) << "Failed to create SysV shared memory region"
<< " errno:" << errno;
return false;
}
void* address = shmat(shmkey, NULL /* desired address */, 0 /* flags */);
// Here we mark the shared memory for deletion. Since we attached it in the
// line above, it doesn't actually get deleted but, if we crash, this means
// that the kernel will automatically clean it up for us.
shmctl(shmkey, IPC_RMID, 0);
if (address == kInvalidAddress)
return false;
TransportDIB* dib = new TransportDIB;
dib->key_ = shmkey;
dib->address_ = address;
dib->size_ = size;
return dib;
}
TransportDIB* TransportDIB::Map(Handle shmkey) {
struct shmid_ds shmst;
if (shmctl(shmkey, IPC_STAT, &shmst) == -1)
return NULL;
void* address = shmat(shmkey, NULL /* desired address */, SHM_RDONLY);
if (address == kInvalidAddress)
return NULL;
TransportDIB* dib = new TransportDIB;
dib->address_ = address;
dib->size_ = shmst.shm_segsz;
dib->key_ = shmkey;
return dib;
}
void* TransportDIB::memory() const {
DCHECK_NE(address_, kInvalidAddress);
return address_;
}
TransportDIB::Id TransportDIB::id() const {
return key_;
}
TransportDIB::Handle TransportDIB::handle() const {
return key_;
}
XID TransportDIB::MapToX(Display* display) {
if (!x_shm_) {
x_shm_ = x11_util::AttachSharedMemory(display, key_);
display_ = display;
}
return x_shm_;
}
|
