fetch_devices.c

   1 #define _GNU_SOURCE
   2 #include <libudev.h>
   3 #include <linux/netlink.h>
   4 #include <netinet/in.h>
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10
  11 #ifndef SOCK_CLOEXEC
  12 #define SOCK_CLOEXEC 0
  13 #endif
  14
  15 #define MONITOR_BUF_SIZE        4096
  16 #define UDEV_MONITOR_MAGIC      0xfeedcafe
  17 struct udev_monitor_netlink_header {
  18         /* "libudev" prefix to distinguish libudev and kernel messages */
  19         char prefix[8];
  20         /*
  21          * magic to protect against daemon <-> library message format mismatch
  22          * used in the kernel from socket filter rules; needs to be stored in network order
  23          */
  24         unsigned int magic;
  25         /* total length of header structure known to the sender */
  26         unsigned int header_size;
  27         /* properties string buffer */
  28         unsigned int properties_off;
  29         unsigned int properties_len;
  30         /*
  31          * hashes of primary device properties strings, to let libudev subscribers
  32          * use in-kernel socket filters; values need to be stored in network order
  33          */
  34         unsigned int filter_subsystem_hash;
  35         unsigned int filter_devtype_hash;
  36         unsigned int filter_tag_bloom_hi;
  37         unsigned int filter_tag_bloom_lo;
  38 };
  39
  40 int main() {
  41         int sock=socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
  42         struct msghdr msg;
  43         struct iovec iov[2];
  44         char val[MONITOR_BUF_SIZE];
  45         ssize_t i;
  46         struct udev_monitor_netlink_header nlh;
  47         struct udev *udev;
  48         struct udev_enumerate *enumerate;
  49         struct udev_list_entry *devices, *dev_list_entry;
  50         struct udev_device *dev;
  51         struct sockaddr_nl dst;
  52
  53         memset(&dst, 0 ,sizeof(dst));
  54         dst.nl_family= AF_NETLINK;
  55         dst.nl_pad=0;
  56         dst.nl_pid=1;
  57         dst.nl_groups=2;
  58
  59         memset(&msg,0,sizeof(msg));
  60         msg.msg_iov = iov;
  61         msg.msg_iovlen = 2;
  62         msg.msg_name = &dst;
  63         msg.msg_namelen = sizeof(dst);
  64
  65         memset(&nlh, 0, sizeof(nlh));
  66         memcpy(nlh.prefix, "libudev", 8);
  67         nlh.magic = htonl(UDEV_MONITOR_MAGIC);
  68         nlh.header_size = sizeof(nlh);
  69         iov[0].iov_base = &nlh;
  70         iov[0].iov_len = sizeof(nlh);
  71         nlh.properties_off = iov[0].iov_len;
  72         nlh.filter_tag_bloom_hi = htonl(0xffffffff);
  73         nlh.filter_tag_bloom_lo = htonl(0xffffffff);
  74
  75         udev = udev_new();
  76         enumerate = udev_enumerate_new(udev);
  77 //      udev_enumerate_add_match_subsystem(enumerate, "block");
  78         udev_enumerate_scan_devices(enumerate);
  79         devices = udev_enumerate_get_list_entry(enumerate);
  80         udev_list_entry_foreach(dev_list_entry, devices) {
  81                 const char *path;
  82                 path = udev_list_entry_get_name(dev_list_entry);
  83                 dev = udev_device_new_from_syspath(udev, path);
  84                 if(udev_device_get_devnum(dev)==0) continue;
  85                 char *tmp;
  86                 int l;
  87                 i=0;
  88                 l=asprintf(&tmp,"ACTION=add");                                  strcpy(val+i,tmp); i+=l+1; free(tmp);
  89                 l=asprintf(&tmp,"DEVNAME=%s",udev_device_get_devnode(dev));     strcpy(val+i,tmp); i+=l+1; free(tmp);
  90                 l=asprintf(&tmp,"DEVPATH=%s",udev_device_get_devpath(dev));     strcpy(val+i,tmp); i+=l+1; free(tmp);
  91                 l=asprintf(&tmp,"DEVTYPE=%s",udev_device_get_devtype(dev));     strcpy(val+i,tmp); i+=l+1; free(tmp);
  92                 l=asprintf(&tmp,"MAJOR=%u",major(udev_device_get_devnum(dev))); strcpy(val+i,tmp); i+=l+1; free(tmp);
  93                 l=asprintf(&tmp,"MINOR=%u",minor(udev_device_get_devnum(dev))); strcpy(val+i,tmp); i+=l+1; free(tmp);
  94                 l=asprintf(&tmp,"SEQNUM=%lld",udev_device_get_seqnum(dev));     strcpy(val+i,tmp); i+=l+1; free(tmp);
  95                 l=asprintf(&tmp,"SUBSYSTEM=%s",udev_device_get_subsystem(dev)); strcpy(val+i,tmp); i+=l+1; free(tmp);
  96                 l=asprintf(&tmp,"TAGS=:systemd:");                              strcpy(val+i,tmp); i+=l+1; free(tmp);
  97                 l=asprintf(&tmp,"UDEV_LOG=%u",udev_get_log_priority(udev));     strcpy(val+i,tmp); i+=l+1; free(tmp);
  98                 l=asprintf(&tmp,"USEC_INITIALIZED=%lld",udev_device_get_usec_since_initialized(dev)); strcpy(val+i,tmp); i+=l+1; free(tmp);
  99                 udev_device_unref(dev);
 100                 iov[1].iov_base = val;
 101                 iov[1].iov_len = i;
 102                 nlh.properties_len = i;
 103                 sendmsg(sock, &msg, 0);
 104         }
 105         udev_enumerate_unref(enumerate);
 106         udev_unref(udev);
 107
 108         close(sock);
 109         return EXIT_SUCCESS;
 110 }