libcallback.c

#define _GNU_SOURCE
#include <dlfcn.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <fcntl.h>
#include <linux/videodev2.h>


static ssize_t (*real_write)(int fd, const void *buf, size_t count) = NULL;
static uint32_t (*real_local_sdk_video_set_encode_frame_callback)(uint32_t param1,uint32_t param2)=NULL;
static uint32_t (*real_local_sdk_video_set_yuv_frame_callback)(uint32_t param1,uint32_t param2)=NULL;
typedef uint32_t (* framecb)(uint32_t);

void *pfunccb=NULL;
void *pfuncycb=NULL;
int cnt=0;
struct v4l2_capability vid_caps;
struct v4l2_format vid_format;
int v4l2_fd;
char v4l2_device_path[255];
static uint32_t test_capture(void *param){
    int ret=0;
    strcpy(v4l2_device_path,"/dev/video1");
    // param is malloc'd pointer
    if( cnt==0 ){
        fprintf(stderr,"Opening V4L2 device: %s ", v4l2_device_path);
        v4l2_fd=open(v4l2_device_path, O_WRONLY, 0777);

        if (v4l2_fd < 0) {
            fprintf(stderr,"Failed to open V4L2 device: %s", v4l2_device_path);
            //return -1;
        }
        memset(&vid_format, 0, sizeof(vid_format));
        vid_format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
        vid_format.fmt.pix.width = 1920;
        vid_format.fmt.pix.height = 1080;

        vid_format.fmt.pix.pixelformat = V4L2_PIX_FMT_H264;
        vid_format.fmt.pix.sizeimage = 0;
        vid_format.fmt.pix.field = V4L2_FIELD_NONE;
        vid_format.fmt.pix.bytesperline = 0;
        vid_format.fmt.pix.colorspace = V4L2_PIX_FMT_YUV420;

        ret = ioctl(v4l2_fd, VIDIOC_S_FMT, &vid_format);
        if (ret < 0) {
            fprintf(stderr,"Unable to set V4L2 device video format: %d", ret);
            //return -1;
        }

        ret = ioctl(v4l2_fd, VIDIOC_STREAMON, &vid_format);
        if (ret < 0) {
            fprintf(stderr,"Unable to perform VIDIOC_STREAMON: %d", ret);
            //return -1;
        }
    }


    uint32_t *ptr=(uint32_t *)param;
    uint32_t length=ptr[1];
    ret = write(v4l2_fd, (void *)(*(uint32_t*)param), length);
    if (ret != length) {
        fprintf(stderr,"Stream write error: %s", ret);
    }
    cnt++;
    return ((framecb)pfunccb)((uint32_t)param);
}

uint32_t local_sdk_video_set_encode_frame_callback(uint32_t param1,uint32_t param2){
    void *handle;
	fprintf(stderr,"!!! injected local_sdk_video_set_encode_frame_callback !!!\n");
	fflush(stderr);

    if (real_local_sdk_video_set_encode_frame_callback == NULL){
        handle = dlopen ("/system/lib/liblocalsdk.so", RTLD_LAZY);
        if (!handle) {
            fputs (dlerror(), stderr);
        }
        real_local_sdk_video_set_encode_frame_callback = dlsym(handle, "local_sdk_video_set_encode_frame_callback");
        fprintf(stderr,"ptr=%d injected!!! err=%s\n",real_local_sdk_video_set_encode_frame_callback,dlerror());
	}
    fprintf(stderr,"param1=0x%x,param2=0x%x,*param2=0x%x",param1,param2,*(int32_t*)param2);
    if(param1==0){
        pfunccb=param2;
        fprintf(stderr,"enc func injection save pcb=0x%x\n",pfunccb);
        param2=(uint32_t)test_capture;
        fprintf(stderr,"override to 0x%x\n",param2);
    }
    int ret=real_local_sdk_video_set_encode_frame_callback(param1,param2);
	return ret;
}