udevsend.c

   1 /*
   2  * udevsend.c
   3  *
   4  * Userspace devfs
   5  *
   6  * Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
   7  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   8  *
   9  *
  10  *      This program is free software; you can redistribute it and/or modify it
  11  *      under the terms of the GNU General Public License as published by the
  12  *      Free Software Foundation version 2 of the License.
  13  *
  14  *      This program is distributed in the hope that it will be useful, but
  15  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *      General Public License for more details.
  18  *
  19  *      You should have received a copy of the GNU General Public License along
  20  *      with this program; if not, write to the Free Software Foundation, Inc.,
  21  *      675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  */
  24
  25 #include <sys/types.h>
  26 #include <sys/socket.h>
  27 #include <sys/wait.h>
  28 #include <sys/un.h>
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <time.h>
  35
  36 #include "udev.h"
  37 #include "udev_version.h"
  38 #include "udevd.h"
  39 #include "logging.h"
  40
  41 unsigned char logname[42];
  42
  43 static inline char *get_action(void)
  44 {
  45         char *action;
  46
  47         action = getenv("ACTION");
  48         return action;
  49 }
  50
  51 static inline char *get_devpath(void)
  52 {
  53         char *devpath;
  54
  55         devpath = getenv("DEVPATH");
  56         return devpath;
  57 }
  58
  59 static inline char *get_seqnum(void)
  60 {
  61         char *seqnum;
  62
  63         seqnum = getenv("SEQNUM");
  64         return seqnum;
  65 }
  66
  67 static int build_hotplugmsg(struct hotplug_msg *msg, char *action,
  68                             char *devpath, char *subsystem, int seqnum)
  69 {
  70         memset(msg, 0x00, sizeof(*msg));
  71         strfieldcpy(msg->magic, UDEV_MAGIC);
  72         msg->seqnum = seqnum;
  73         strncpy(msg->action, action, 8);
  74         strncpy(msg->devpath, devpath, 128);
  75         strncpy(msg->subsystem, subsystem, 16);
  76         return sizeof(struct hotplug_msg);
  77 }
  78
  79 static int start_daemon(void)
  80 {
  81         pid_t pid;
  82         pid_t child_pid;
  83
  84         pid = fork();
  85         switch (pid) {
  86         case 0:
  87                 /* helper child */
  88                 child_pid = fork();
  89                 switch (child_pid) {
  90                 case 0:
  91                         /* daemon */
  92                         setsid();
  93                         chdir("/");
  94                         execl(UDEVD_BIN, "udevd", NULL);
  95                         dbg("exec of daemon failed");
  96                         exit(1);
  97                 case -1:
  98                         dbg("fork of daemon failed");
  99                         return -1;
 100                 default:
 101                         exit(0);
 102                 }
 103                 break;
 104         case -1:
 105                 dbg("fork of helper failed");
 106                 return -1;
 107         default:
 108                 wait(NULL);
 109         }
 110         return 0;
 111 }
 112
 113 int main(int argc, char* argv[])
 114 {
 115         struct hotplug_msg message;
 116         char *action;
 117         char *devpath;
 118         char *subsystem;
 119         char *seqnum;
 120         int seq;
 121         int retval = -EINVAL;
 122         int size;
 123         int loop;
 124         struct timespec tspec;
 125         int sock;
 126         struct sockaddr_un saddr;
 127
 128 #ifdef DEBUG
 129         init_logging("udevsend");
 130 #endif
 131
 132         subsystem = argv[1];
 133         if (subsystem == NULL) {
 134                 dbg("no subsystem");
 135                 goto exit;
 136         }
 137
 138         devpath = get_devpath();
 139         if (devpath == NULL) {
 140                 dbg("no devpath");
 141                 goto exit;
 142         }
 143
 144         action = get_action();
 145         if (action == NULL) {
 146                 dbg("no action");
 147                 goto exit;
 148         }
 149
 150         seqnum = get_seqnum();
 151         if (seqnum == NULL)
 152                 seq = 0;
 153         else
 154                 seq = atoi(seqnum);
 155
 156         sock = socket(AF_LOCAL, SOCK_STREAM, 0);
 157         if (sock == -1) {
 158                 dbg("error getting socket");
 159                 goto exit;
 160         }
 161
 162         memset(&saddr, 0x00, sizeof(saddr));
 163         saddr.sun_family = AF_LOCAL;
 164         strcpy(saddr.sun_path, UDEVD_SOCK);
 165
 166         /* try to connect, if it fails start daemon */
 167         retval = connect(sock, (struct sockaddr *) &saddr, sizeof(saddr));
 168         if (retval != -1) {
 169                 goto send;
 170         } else {
 171                 dbg("connect failed, try starting daemon...");
 172                 retval = start_daemon();
 173                 if (retval == 0) {
 174                         dbg("daemon started");
 175                 } else {
 176                         dbg("error starting daemon");
 177                         goto exit;
 178                 }
 179         }
 180
 181         /* try to connect while daemon to starts */
 182         tspec.tv_sec = 0;
 183         tspec.tv_nsec = 100000000;  /* 100 millisec */
 184         loop = UDEVSEND_CONNECT_RETRY;
 185         while (loop--) {
 186                 retval = connect(sock, (struct sockaddr *) &saddr, sizeof(saddr));
 187                 if (retval != -1)
 188                         goto send;
 189                 else
 190                         dbg("retry to connect %d",
 191                             UDEVSEND_CONNECT_RETRY - loop);
 192                 nanosleep(&tspec, NULL);
 193         }
 194         dbg("error connecting to daemon, start daemon failed");
 195         goto exit;
 196
 197 send:
 198         size = build_hotplugmsg(&message, action, devpath, subsystem, seq);
 199         retval = send(sock, &message, size, 0);
 200         if (retval == -1) {
 201                 dbg("error sending message");
 202                 close (sock);
 203                 goto exit;
 204         }
 205         close (sock);
 206         return 0;
 207
 208 exit:
 209         return 1;
 210 }