udev_find_serial_by_vid_pid.c

// cc $(pkg-config --cflags --libs libudev) udev_find_serial_by_vid_pid.c -o udev_find_serial_by_vid_pid

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libudev.h>

int main(int argc, char **argv)
{
        if (argc != 3) {
                fprintf(stderr, "Usage: %s VID PID\n", argv[0]);
                return 1;
        }

        struct udev *ctx = udev_new();
        struct udev_enumerate *enm = udev_enumerate_new(ctx);

        udev_enumerate_add_match_subsystem(enm, "tty");
        udev_enumerate_add_match_property(enm, "ID_BUS", "usb");
        udev_enumerate_scan_devices(enm);

        int found = 0;
        struct udev_list_entry *devices = udev_enumerate_get_list_entry(enm), *device;
        udev_list_entry_foreach(device, devices) {
                const char *syspath = udev_list_entry_get_name(device);
                struct udev_device *dev = udev_device_new_from_syspath(ctx, syspath);
                if (!strcmp(udev_device_get_property_value(dev, "ID_VENDOR_ID"), argv[1]) &&
                    !strcmp(udev_device_get_property_value(dev, "ID_MODEL_ID"), argv[2])) {
                        puts(udev_device_get_devnode(dev));
                        found = 1;
                }
                udev_device_unref(dev);
        }

        udev_enumerate_unref(enm);
        udev_unref(ctx);
        return (found == 1) ? 0 : 1;
}