uevents.c

   1 /*******************************************************************************
   2 this code is protected by the GNU affero GPLv3
   3 author:Sylvain BERTRAND <sylvain.bertrand AT gmail dot com>
   4 *******************************************************************************/
   5 #include <ulinux/compiler_types.h>
   6 #include <ulinux/sysc.h>
   7 #include <ulinux/types.h>
   8 #include <ulinux/error.h>
   9 #include <ulinux/socket/socket.h>
  10 #include <ulinux/socket/msg.h>
  11 #include <ulinux/socket/netlink.h>
  12 #include <ulinux/epoll.h>
  13 #include <ulinux/utils/mem.h>
  14
  15 #include "out.h"
  16 #include "ulinux_namespace.h"
  17 #include "globals.h"
  18 #include "uevent.h"
  19 static i ep_fd;
  20 static i so;
  21
  22 void uevents_cleanup(void)
  23 {
  24   l r;
  25   loop{
  26     r=close(ep_fd);
  27     if(r!=-EINTR) break;
  28   }
  29   if(ISERR(r)){
  30     OUT("ERROR(%ld):unable to close epoll fd\n",r);
  31     exit_group(-1);
  32   }
  33
  34   loop{
  35     r=close(so);
  36     if(r!=-EINTR) break;
  37   }
  38   if(ISERR(r)){
  39     OUT("ERROR(%ld):unable to close netlink socket\n",r);
  40     exit_group(-1);
  41   }
  42 }
  43
  44 void uevents_setup(void)
  45 {
  46   i recv_buf_sz;
  47   i r;
  48   struct sockaddr_nl addr={AF_NETLINK,0,0,1};
  49   struct epoll_event ep_evt;
  50
  51   OUT(PRE "setting up uevent...");
  52   ep_fd=(i)epoll_create1(0);
  53   if(ISERR(ep_fd)){
  54     OUT("ERROR(%d):unable to create epoll fd\n",ep_fd);
  55     exit_group(-1);
  56   }
  57
  58   /*--------------------------------------------------------------------------*/
  59
  60   /* blocking socket */
  61   so=(i)socket(PF_NETLINK,SOCK_RAW,NETLINK_KOBJECT_UEVENT);
  62   if(ISERR(so)){
  63     OUT("ERROR(%d):unable to create uevent netlink socket\n",so);
  64     exit_group(-1);
  65   }
  66
  67   /*--------------------------------------------------------------------------*/
  68
  69   recv_buf_sz=128*1024;/* 128k for kernel buffering */
  70   r=setsockopt(so,SOL_SOCKET,SO_RCVBUFFORCE,&recv_buf_sz,sizeof(recv_buf_sz));
  71   if(ISERR(r)){
  72     OUT("ERROR(%ld):unable to force the size of the socket buffer\n",r);
  73     exit_group(-1);
  74   }
  75
  76   /*--------------------------------------------------------------------------*/
  77
  78   /* uevent groups-->only one: 1 */
  79   r=bind(so,&addr,sizeof(addr));
  80   if(ISERR(r)){
  81     OUT("ERROR(%ld):unable to bind address to uevent netlink socket\n",r);
  82     exit_group(-1);
  83   }
  84
  85   /*--------------------------------------------------------------------------*/
  86
  87   memset(&ep_evt,0,sizeof(ep_evt));
  88   ep_evt.events=EPOLLIN;
  89   ep_evt.data.fd=so;
  90   r=epoll_ctl(ep_fd,EPOLL_CTL_ADD,so,&ep_evt);
  91   if(ISERR(r)){
  92     OUT("ERROR(%ld):unable to register uevent netlink socket to epoll\n",r);
  93     exit_group(-1);
  94   }
  95   OUT("done\n");
  96 }
  97
  98 static u8 uevent_msg(void)
  99 {
 100   u8 buf[8192];/*presume 8kB is enough for one message*/
 101   struct io_vec uev_io_vec;
 102   struct msg_hdr msg;
 103   l r;
 104
 105   memset(buf,0,sizeof(buf));
 106
 107   uev_io_vec.base=buf;
 108   uev_io_vec.len=sizeof(buf);
 109
 110   memset(&msg,0,sizeof(msg));
 111   msg.iov=&uev_io_vec;
 112   msg.iov_len=1;
 113
 114   loop{
 115     r=recvmsg(so,&msg,0);
 116     if(r!=-EINTR) break;
 117   }
 118   if(ISERR(r)){
 119     OUT("ERROR(%ld):unable to receive the uevent\n",r);
 120     exit_group(-1);
 121   }
 122   if(msg.flgs&MSG_TRUNC){
 123     OUT("ERROR:the uevent was truncated(flags=0x%x)\n",msg.flgs);
 124     exit_group(-1);
 125   }
 126   return uevent_process(&buf[0],(i)r);
 127 }
 128
 129 u8 uevents_process(void)
 130 {
 131   u8 r;
 132
 133   r=ROOT_NOT_FOUND;
 134   OUT(PRE "processing uevents...\n");
 135   loop{
 136     l r1;
 137     static struct epoll_event evts;/*uevent netlink event*/
 138     loop{
 139       memset(&evts,0,sizeof(evts));
 140       r1=epoll_wait(ep_fd,&evts,1,UEVENTS_TIMEOUT);
 141
 142       if(r1!=-EINTR) break;
 143     }
 144     if(ISERR(r1)){
 145       OUT(PRE "ERROR(%ld):error epolling uevent netlink socket\n",r1);
 146       exit_group(-1);
 147     }
 148     if(!r1) break;/*assume no more uevents and unable to find root*/
 149     if(evts.events&EPOLLIN){
 150       r=uevent_msg();
 151       if(r==ROOT_FOUND) break;
 152     }else{
 153       OUT(PRE "ERROR:unmanaged epolling event on uevent netlink socket(events=%u)\n",
 154                                                                    evts.events);
 155       exit_group(-1);
 156     }
 157   }
 158   OUT(PRE "uevents processing terminated\n");
 159   return r;
 160 }