Haven't tried this myself, but libudev's udev_device_get_property_value should be it; it is used in pulseaudio's udev-util.c as udev_device_get_property_value(card, "ID_VENDOR_FROM_DATABASE"))
.
Here is a small example I just put together, based on udev-util.c
- note that I've used an Arduino Duemillanove with FTDI FT232 chip, whose udev path I find using udevadm
(see comments in code below), and then I hardcoded it in the below program, udevl.c
:
// sudo apt-get install libudev-dev
// build with: gcc -o udevl -ludev -Wall -g udevl.c
#include <stdio.h>
#include <libudev.h>
int main( int argc, char **argv )
{
const char *v;
char t[256];
struct udev *udev;
struct udev_device *card = NULL;
if (!(udev = udev_new())) {
fprintf(stderr, "Failed to allocate udev context.\n");
return -1;
}
// $ lsusb | grep FT232
// Bus 002 Device 002: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
// $ udevadm info --name=/dev/ttyUSB0 --attribute-walk | grep "looking at device"
// looking at device '/devices/pci0000:00/0000:00:1d.0/usb2/2-2/2-2:1.0/ttyUSB0/tty/ttyUSB0'
// (that one is under /sys)
// hardcode that path below:
// udev_get_sys_path(udev) for me: '/sys'
sprintf(t, "%s/devices/pci0000:00/0000:00:1d.0/usb2/2-2/2-2:1.0/ttyUSB0/tty/ttyUSB0", udev_get_sys_path(udev));
fprintf(stdout, " path: %s\n", t);
card = udev_device_new_from_syspath(udev, t);
fprintf(stdout, " udev_device: 0x%08X\n", (unsigned int)card);
if ((v = udev_device_get_property_value(card, "ID_MODEL_FROM_DATABASE")) )
fprintf(stdout, "got ID_MODEL_FROM_DATABASE: %s\n", v);
else
fprintf(stdout, "failed getting ID_MODEL_FROM_DATABASE: %s\n", v);
fprintf(stdout, "Done.\n");
if (card)
udev_device_unref(card);
if (udev)
udev_unref(udev);
return 0;
}
This program (with the Arduino attached) outputs:
$ ./udevl
path: /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-2/2-2:1.0/ttyUSB0/tty/ttyUSB0
udev_device: 0x09FBF080
got ID_MODEL_FROM_DATABASE: FT232 USB-Serial (UART) IC
Done.
... and "FT232 USB-Serial (UART) IC" is the right entry for VID:PID 0403:6001 in usb.ids.
Hope this helps,
Cheers!
/usr/share/usb.ids
. Can't find any standard that governs the place for this file. – Mesne