/**
 * This program's outputs.
 * 
root@slax:~# ./a.out 
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/bsg/5:0:0:0
change@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/block/sdb
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/scsi_device/5:0:0:0
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/scsi_disk/5:0:0:0
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/block/sdb/sdb1
remove@/devices/virtual/bdi/8:16
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0/block/sdb
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/target5:0:0/5:0:0:0
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5/scsi_host/host5
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host5
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0
remove@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1
remove@/host5/target5:0:0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/scsi_host/host6
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0/scsi_disk/6:0:0:0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0/scsi_device/6:0:0:0
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0/bsg/6:0:0:0
add@/devices/virtual/bdi/8:16
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0/block/sdb
add@/devices/pci0000:00/0000:00:15.0/0000:03:00.0/usb3/3-2/3-2.1/3-2.1:1.0/host6/target6:0:0/6:0:0:0/block/sdb/sdb1 
*/

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <linux/netlink.h>

#define UEVENT_BUFFER_SIZE      2048

static int init_hotplug_sock(void)
{
    struct sockaddr_nl snl;
    const int buffersize = 16 * 1024 * 1024;
    int retval;

    memset(&snl, 0x00, sizeof(struct sockaddr_nl));
    snl.nl_family = AF_NETLINK;
    snl.nl_pid = getpid();
    snl.nl_groups = 1;

    int hotplug_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
    if (hotplug_sock == -1) {
        printf("error getting socket: %s", strerror(errno));
        return -1;
    }

    /* set receive buffersize */
    setsockopt(hotplug_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
    retval = bind(hotplug_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
    if (retval < 0) {
        printf("bind failed: %s", strerror(errno));
        close(hotplug_sock);
        hotplug_sock = -1;
        return -1;
    }
    return hotplug_sock;
}

int main(int argc, char* argv[])
{
    int hotplug_sock = init_hotplug_sock();
    
    while(1)
    {
      //printf("sunqidong debug\n");
      char buf[UEVENT_BUFFER_SIZE*2] = {0};
      recv(hotplug_sock, &buf, sizeof(buf), 0);
      printf("%s\n", buf);
    }
    return 0;
}