android /system/vold源码分析(8)

DirectVolume::handleBlockEvent
int DirectVolume::handleBlockEvent(NetlinkEvent *evt) {
const char *dp = evt->findParam("DEVPATH");

PathCollection::iterator it;
for (it = mPaths->begin(); it != mPaths->end(); ++it) {
if (!strncmp(dp, *it, strlen(*it))) { //比较字符
/* We can handle this disk */
int action = evt->getAction();
const char *devtype = evt->findParam("DEVTYPE");

if (action == NetlinkEvent::NlActionAdd) {
int major = atoi(evt->findParam("MAJOR"));
int minor = atoi(evt->findParam("MINOR"));
char nodepath[255];

snprintf(nodepath,
sizeof(nodepath), "/dev/block/vold/%d:%d",
major, minor);
//创建设备结点/dev/block/volk/主设备号:次设备号
if (createDeviceNode(nodepath, major, minor)) {
SLOGE("Error making device node '%s' (%s)", nodepath,
strerror(errno));
}
if (!strcmp(devtype, "disk")) {
handleDiskAdded(dp, evt);
} else {
handlePartitionAdded(dp, evt);
}
/* Send notification iff disk is ready (ie all partitions found) */
if (getState() == Volume::State_Idle) {
char msg[255];

snprintf(msg, sizeof(msg),
"Volume %s %s disk inserted (%d:%d)", getLabel(),
getFuseMountpoint(), mDiskMajor, mDiskMinor);
mVm->getBroadcaster()->sendBroadcast(ResponseCode::VolumeDiskInserted,
msg, false);
}
} else if (action == NetlinkEvent::NlActionRemove) {
if (!strcmp(devtype, "disk")) {
handleDiskRemoved(dp, evt);
} else {
handlePartitionRemoved(dp, evt);
}
} else if (action == NetlinkEvent::NlActionChange) {
if (!strcmp(devtype, "disk")) {
handleDiskChanged(dp, evt);
} else {
handlePartitionChanged(dp, evt);
}
} else {
SLOGW("Ignoring non add/remove/change event");
}

return 0;
}
}
errno = ENODEV;
return -1;
}

这段代码处理了块设备的添加、删除和改变。