Andorid TF卡挂载流程

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于 2025-04-12 10:54:28 发布 · 436 阅读

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#java #c++

TF卡挂载流程

1. 驱动层TF卡消息通过socket发送给vold

vold启动如下

system\vold\main.cpp
int main(int argc, char** argv) {
   
   
	......
	VolumeManager* vm;
    NetlinkManager* nm;
    if (!(vm = VolumeManager::Instance())) {
   
   
        LOG(ERROR) << "Unable to create VolumeManager";
        exit(1);
    }
    
    if (!(nm = NetlinkManager::Instance())) {
   
   
        LOG(ERROR) << "Unable to create NetlinkManager";
        exit(1);
    }
    
    if (android::vold::VoldNativeService::start() != android::OK) {
   
   
        LOG(ERROR) << "Unable to start VoldNativeService";
        exit(1);
    }
	......
}

2. NetlinkManager socket建立

//文件：system\vold\NetlinkManager.cpp
int NetlinkManager::start() {
   
   
    struct sockaddr_nl nladdr;
    int sz = 64 * 1024;
    int on = 1;
	memset(&nladdr, 0, sizeof(nladdr));
    nladdr.nl_family = AF_NETLINK;
    nladdr.nl_pid = getpid();
    nladdr.nl_groups = 0xffffffff;
    if ((mSock = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT)) < 0) {
   
   
        PLOG(ERROR) << "Unable to create uevent socket";
        return -1;
    }
    if ((setsockopt(mSock, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz)) < 0) &&
        (setsockopt(mSock, SOL_SOCKET, SO_RCVBUF, &sz, sizeof(sz)) < 0)) {
   
   
         PLOG(ERROR) << "Unable to set uevent socket SO_RCVBUF/SO_RCVBUFFORCE option";
        goto out;
    }
    if (setsockopt(mSock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) {
   
   
        PLOG(ERROR) << "Unable to set uevent socket SO_PASSCRED option";
        goto out;
    }
    if (bind(mSock, (struct sockaddr*)&nladdr, sizeof(nladdr)) < 0) {
   
   
        PLOG(ERROR) << "Unable to bind uevent socket";
        goto out;
    }
    mHandler = new NetlinkHandler(mSock);
        if (mHandler->start()) {
   
   
        PLOG(ERROR) << "Unable to start NetlinkHandler";
        goto out;
    }
    return 0;
out:
    close(mSock);
    return -1;
}

3. NetlinkHandler消息接收

//文件：system\vold\NetlinkHandler.cpp
void NetlinkHandler::onEvent(NetlinkEvent* evt) {
   
   
    VolumeManager* vm = VolumeManager::Instance();
    const char*

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