Send a USB port reset to a USB device

usbreset.c

/*
usbreset -- send a USB port reset to a USB device

http://askubuntu.com/questions/645#answer-661

    cc usbreset.c -o usbreset

    lsusb |grep DUB
    Bus 001 Device 021: ID 2001:1a02 D-Link Corp. DUB-E100 Fast Ethernet Adapter(rev.C1) [ASIX AX88772]

    sudo /home/stav/bin/usbreset /dev/bus/usb/001/007
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>

#include <linux/usbdevice_fs.h>


int main(int argc, char **argv)
{
    const char *filename;
    int fd;
    int rc;

    if (argc != 2) {
        fprintf(stderr, "Usage: usbreset device-filename\n");
        return 1;
    }
    filename = argv[1];

    fd = open(filename, O_WRONLY);
    if (fd < 0) {
        perror("Error opening output file");
        return 1;
    }

    printf("Resetting USB device %s\n", filename);
    rc = ioctl(fd, USBDEVFS_RESET, 0);
    if (rc < 0) {
        perror("Error in ioctl");
        return 1;
    }
    printf("Reset successful\n");

    close(fd);
    return 0;
}

See also the more complete Python version.