#include <libudev.h> #include <stdio.h> #include <stdlib.h> #include <locale.h> #include <unistd.h> int main(void) { struct udev *udev; struct udev_enumerate *enumerate; struct udev_list_entry *devices, *dev_list_entry; struct udev_device *dev; /* Create the udev object */ udev = udev_new(); if (!udev) { printf("Can't create udev\n"); exit(1); } /* Create a list of the devices in the 'hidraw' subsystem. */ enumerate = udev_enumerate_new ( udev ); udev_enumerate_add_match_subsystem ( enumerate, "hidraw" ); udev_enumerate_scan_devices ( enumerate ); devices = udev_enumerate_get_list_entry ( enumerate ); /* For each item enumerated, print out its information. udev_list_entry_foreach is a macro which expands to a loop. The loop will be executed for each member in devices, setting dev_list_entry to a list entry which contains the device's path in `/sys.` */ udev_list_entry_foreach(dev_list_entry, devices) { const char *path; // Get the filename of the /sys entry for the device // and create a udev_device object (dev) representing it path = udev_list_entry_get_name(dev_list_entry); dev = udev_device_new_from_syspath(udev, path); /* usb_device_get_devnode() returns the path to the device node itself in /dev. */ printf("Device Node Path: %s\n", udev_device_get_devnode(dev)); /* The device pointed to by dev contains information about the hidraw device. In order to get information about the USB device, get the parent device with the subsystem/devtype pair of "usb"/"usb_device". This will be several levels up the tree, but the function will find it.*/ dev = udev_device_get_parent_with_subsystem_devtype( dev, "usb", "usb_device"); if (!dev) { printf("Unable to find parent usb device."); exit(1); } /* From here, we can call get_sysattr_value() for each file in the device's /sys entry. The strings passed into these functions (idProduct, idVendor, serial, etc.) correspond directly to the files in the directory which represents the USB device. Note that USB strings are Unicode, UCS2 encoded, but the strings returned from udev_device_get_sysattr_value() are UTF-8 encoded. */ printf(" VID/PID: %s %s\n", udev_device_get_sysattr_value(dev,"idVendor"), udev_device_get_sysattr_value(dev, "idProduct")); printf(" %s\n %s\n", udev_device_get_sysattr_value(dev,"manufacturer"), udev_device_get_sysattr_value(dev,"product")); printf(" serial: %s\n", udev_device_get_sysattr_value(dev, "serial")); udev_device_unref(dev); } /* Free the enumerator object */ udev_enumerate_unref(enumerate); udev_unref(udev); return 0; }