framebuffer_service.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdlib.h>
18#include <stdio.h>
19#include <unistd.h>
20#include <string.h>
21#include <fcntl.h>
22
23#include <cutils/fdevent.h>
24#include "adb.h"
25
26#include <linux/fb.h>
27#include <sys/mman.h>
28
29/* TODO:
30** - grab the current buffer, not the first buffer
31** - sync with vsync to avoid tearing
32*/
33
34void framebuffer_service(int fd, void *cookie)
35{
36    struct fb_var_screeninfo vinfo;
37    int fb;
38    void *ptr = MAP_FAILED;
39    char x;
40
41    unsigned fbinfo[4];
42
43    fb = open("/dev/graphics/fb0", O_RDONLY);
44    if(fb < 0) goto done;
45
46    if(ioctl(fb, FBIOGET_VSCREENINFO, &vinfo) < 0) goto done;
47    fcntl(fb, F_SETFD, FD_CLOEXEC);
48
49    fbinfo[0] = 16;
50    fbinfo[1] = vinfo.xres * vinfo.yres * 2;
51    fbinfo[2] = vinfo.xres;
52    fbinfo[3] = vinfo.yres;
53
54    ptr = mmap(0, fbinfo[1], PROT_READ, MAP_SHARED, fb, 0);
55    if(ptr == MAP_FAILED) goto done;
56
57    if(writex(fd, fbinfo, sizeof(unsigned) * 4)) goto done;
58
59    for(;;) {
60        if(readx(fd, &x, 1)) goto done;
61        if(writex(fd, ptr, fbinfo[1])) goto done;
62    }
63
64done:
65    if(ptr != MAP_FAILED) munmap(ptr, fbinfo[1]);
66    if(fb >= 0) close(fb);
67    close(fd);
68}
69
70