I want to turn ON/OFF some port bits on ttyS2 suspend/resume scenario but from driver code it is difficult to find code stub where I can check for ttyS2 and set/unset bits on suspend/resume.
Can anyone point be specific location or logic where i can decode port name and do specific action?
You should do it in user space.
One can look for driver name using "kobject_name" as registered by device driver. For serial driver we get tty instance number on specific platform.
Related
I just want to know how to find a usb device is connected to USB3.0 or USB2.0 port in window . I am using c++ and win32 API. please let me know your thoughts.
Based on how your question is phrased, I assume that you know when a device is connected, and need to know if the port it's connected is capable of USB 3.0 speeds.
Take a look at the USB_NODE_CONNECTION_INFORMATION_EX structure, and specifically the field Speed in it, which could correspond to a value defined in the enum USB_DEVICE_SPEED. For USB 3.0, the value of Speed would be UsbSuperSpeed.
The documentation page says that you could use IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX request to obtain information about the connection associated with the indicated USB port.
You may also find the following remarks from the documentation helpful:
If there is no device connected, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX just returns information about the port.
If a device is connected to the port IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX returns information about both the port and the connected device.
The USB_NODE_CONNECTION_INFORMATION_EX structure is an extended version of USB_NODE_CONNECTION_INFORMATION. The two structures are identical, except for one member. In the extended structure, the Speed member indicates the device speed.
I'd also encourage you to single-step through the usbview project which is part of the windows driver samples available in Github.
I am modifying a monitor controller for a prototype. It would be convenient to send commands to the prototype using DDC/CI. In Windows, I can't find an obvious way to send a DDC/CI command to a "display dependent device".
The Monitor Configuration API can send virtual control panel commands, but it does not give access to display dependent devices (which would have an I2C address other than 0x6e).
Nicomsoft's WinI2C/DDC product seems to give access to a display dependent device, but it is end-of-life. I would prefer not to build a dependency on an end-of-life product.
NVIDIA's NVAPI has an I2C API, but I would like a solution that also works with Intel and AMD graphics adaptors.
A solution exists for windows which respect XDDM driver display model. Windows 8 and 10 use WDDM.
In XDDM there is a windows O.S. supplied video port driver, and the hardware vendor supplies a miniport driver. When the miniport driver call's the video port driver's edid helper api (VideoPortDDCMonitorHelper), the miniport must supply 4 i2c function pointers as arguments.
In order to utilize these interfaces however you must be acting as the video port driver. So you have to write a video port lower filter driver which just passes along all the interfaces on from the windows supplied video port driver to the miniport driver. Hook the api's and export them to a usermode driver or ioctl which an application can call.
It may be possible to simply mount an instance of the miniport driver and some how get it to call VideoPortDDCMonitorHelper. But with out the help of the actual video port driver it would be difficult to get guidance on how to do that. Also you would have 2 instances of the driver running which may be against the rules for windows.
It does not appear this solution works for windows 8 and 10 because they use a different display driver model which doesn't appear to expose low level control of i2c. It is internal to the miniport driver.
I'm attempting to set up a USB serial port using:
GNAT.SERIAL_COMMUNICATIONS.
I am able to open the port but when I try to set attributes of the port I get the following exception
raised GNAT.SERIAL_COMMUNICATIONS.SERIAL_ERROR : set: cannot get comm state ( 6)
Any ideas?
Sean
Since what you are working with is not a natural Windows COM port, but an extra COM port created by a device driver, you may be interested in this question (and in particular my answer to it).
The digest is that sometimes virtual COM ports aren't accessible to programs with the normal name. Before giving up on "COM2", try "\\.\COM2"
I need to create a Cocoa app that will create a virtual serial port available to other apps, meaning registered in the IO Kit Registry.
Gist of the app:
Create a virtual serial port (listed in /dev and registered with the IOKit Registry)
Initiate a tcp connection out to another computer
Proxy everything received on the virtual serial port out to the
network and vice versa.
This app will be used by third party apps that talk to serial ports on the computer, allowing for the particular serial device to be located across the network. The Cocoa and network part is no problem, I've written several apps that talk over the network. My hangup is the serial port.
I've done the test with socat/netcat/minicom to verify that it all works to proxy pty/tty traffic over the network but the tty I use doesn't show up as usable by random applications because it's not registered in the IO Kit Registry.
While I can use a pty/tty master/slave for the communication, I need this slave tty to show up to Mac applications. What would be very handy is a way to register a tty in the IO Kit Registry.
Do I really need to create a custom IOKit kext driver that gets registered at Cocoa app runtime? If so, I have a big learning curve ahead of me. Where should I start reading? Or, can I use IOKit to create a virtual serial port and register it as a usable serial port for applications without having to load any kernel extensions?
Thank you for any help you can provide,
Stateful
First of all, have you checked if you can borrow a solution from this app? It's not obvious from the website if they've managed to get their virtual serial ports fully integrated into the system.
If there is a way to do it from user space, I'm not aware of it. The user-space IOKit API generally doesn't let you create class instances, let alone new device driver classes. Maybe you can somehow otherwise persuade the Cocoa libraries to find it despite not being registered in the kernel.
I don't know if you could get away with creating a "dummy" serial port in the kernel and then move your tty into its place in /dev from your userspace daemon. Maybe that's an option.
In case you do have to do it all in the kernel:
The virtual driver itself shouldn't be too much work, at least, though it will require some time to get up to speed with kernel dev. Unfortunately, the documentation is pretty thin for serial port drivers - the key is subclassing the IOSerialDriverSync abstract class. Just about the only description I've seen is in Ole Henry Halvorsen's OSX and iOS Kernel Programming book. It also has a fragment of an example for the reading & writing operations. (disclosure: I was one of the tech reviewers for this book; I don't receive any incentives for recommending it - in this case it's literally the only documentation I know of) You can find the source for a complete serial port driver in Apple's USBCDC driver, AppleUSBCDCDMM is the class that actually represents the serial port node.
It's relatively straightforward to open a so-called "kernel control" socket in the kernel, the individual APIs are documented here; from user space you use the normal BSD socket send/recv APIs. (this is also described in the aforementioned book) Your daemon can then connect to that, and all you'd need to do is push the data between the socket and the virtual serial port device. You'll need to handle disconnect events and such correctly of course.
Still, I think this is achievable as a first kernel project for an experienced C programmer (with some C++).
I hope that helps!
Is it possible to detect if some serial port is being sniffed by another process running on Windows?
We have an application that receives some sensitive data that cannot be read by other people. So, before opening the serial port, we need to check if the port is being monitored.
We can use the CreateFile Windows API function to open the serial port with exclusive access rights, but if the monitor runs before our call, it can read all the communication (it opens the serial port with shared access rights, so we can open the port at the same time). To avoid this, the attempt is to check if the port is being monitored and raise an exception, warning the user. Is it possible to do this?
Port sniffing requires a filter driver, like SysInternals' PortMon utility. You are taking the wrong kind of approach to secure your application. When somebody can install a filter driver, the attacker has more than enough privileges to completely disable your app and replace it with something else of his own making. Trying to detect and prevent information loss through your app is pointless, the system itself has to be secured. A serial port is probably the first thing you'll have to lose, it is trivial to tap its wires.
Rather than lose the serial port why not encrypt your data. This assumes that both the DTE and DCE are programmable.