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 <time.h>
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <stddef.h>
  34 #include <string.h>
  35 #include <unistd.h>
  36 #include <linux/stddef.h>
  37
  38 #include "udev.h"
  39 #include "udev_lib.h"
  40 #include "udev_version.h"
  41 #include "udevd.h"
  42 #include "logging.h"
  43
  44 #ifdef LOG
  45 unsigned char logname[LOGNAME_SIZE];
  46 void log_message (int level, const char *format, ...)
  47 {
  48         va_list args;
  49
  50         va_start(args, format);
  51         vsyslog(level, format, args);
  52         va_end(args);
  53 }
  54 #endif
  55
  56 static void build_hotplugmsg(struct hotplug_msg *msg, char *action,
  57                              char *devpath, char *subsystem, int seqnum)
  58 {
  59         memset(msg, 0x00, sizeof(struct hotplug_msg));
  60         strfieldcpy(msg->magic, UDEV_MAGIC);
  61         msg->seqnum = seqnum;
  62         strfieldcpy(msg->action, action);
  63         strfieldcpy(msg->devpath, devpath);
  64         strfieldcpy(msg->subsystem, subsystem);
  65 }
  66
  67 static int start_daemon(void)
  68 {
  69         pid_t pid;
  70         pid_t child_pid;
  71
  72         pid = fork();
  73         switch (pid) {
  74         case 0:
  75                 /* helper child */
  76                 child_pid = fork();
  77                 switch (child_pid) {
  78                 case 0:
  79                         /* daemon */
  80                         setsid();
  81                         chdir("/");
  82                         execl(UDEVD_BIN, "udevd", NULL);
  83                         dbg("exec of daemon failed");
  84                         exit(1);
  85                 case -1:
  86                         dbg("fork of daemon failed");
  87                         return -1;
  88                 default:
  89                         exit(0);
  90                 }
  91                 break;
  92         case -1:
  93                 dbg("fork of helper failed");
  94                 return -1;
  95         default:
  96                 wait(NULL);
  97         }
  98         return 0;
  99 }
 100
 101 int main(int argc, char* argv[])
 102 {
 103         struct hotplug_msg msg;
 104         char *action;
 105         char *devpath;
 106         char *subsystem;
 107         char *seqnum;
 108         int seq;
 109         int retval = 1;
 110         int loop;
 111         struct timespec tspec;
 112         int sock;
 113         struct sockaddr_un saddr;
 114         socklen_t addrlen;
 115         int started_daemon = 0;
 116
 117 #ifdef DEBUG
 118         init_logging("udevsend");
 119 #endif
 120         dbg("version %s", UDEV_VERSION);
 121
 122         subsystem = get_subsystem(argv[1]);
 123         if (subsystem == NULL) {
 124                 dbg("no subsystem");
 125                 goto exit;
 126         }
 127         dbg("subsystem = '%s'", subsystem);
 128
 129         devpath = get_devpath();
 130         if (devpath == NULL) {
 131                 dbg("no devpath");
 132                 goto exit;
 133         }
 134         dbg("DEVPATH = '%s'", devpath);
 135
 136         action = get_action();
 137         if (action == NULL) {
 138                 dbg("no action");
 139                 goto exit;
 140         }
 141         dbg("ACTION = '%s'", action);
 142
 143         seqnum = get_seqnum();
 144         if (seqnum == NULL)
 145                 seq = -1;
 146         else
 147                 seq = atoi(seqnum);
 148         dbg("SEQNUM = '%d'", seq);
 149
 150         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 151         if (sock == -1) {
 152                 dbg("error getting socket");
 153                 goto exit;
 154         }
 155
 156         memset(&saddr, 0x00, sizeof(struct sockaddr_un));
 157         saddr.sun_family = AF_LOCAL;
 158         /* use abstract namespace for socket path */
 159         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 160         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 161
 162         build_hotplugmsg(&msg, action, devpath, subsystem, seq);
 163
 164         /* If we can't send, try to start daemon and resend message */
 165         loop = UDEVSEND_CONNECT_RETRY;
 166         while (loop--) {
 167                 retval = sendto(sock, &msg, sizeof(struct hotplug_msg), 0,
 168                                 (struct sockaddr *)&saddr, addrlen);
 169                 if (retval != -1) {
 170                         retval = 0;
 171                         goto close_and_exit;
 172                 }
 173
 174                 if (errno != ECONNREFUSED) {
 175                         dbg("error sending message");
 176                         goto close_and_exit;
 177                 }
 178
 179                 if (!started_daemon) {
 180                         dbg("connect failed, try starting daemon...");
 181                         retval = start_daemon();
 182                         if (retval) {
 183                                 dbg("error starting daemon");
 184                                 goto exit;
 185                         }
 186
 187                         dbg("daemon started");
 188                         started_daemon = 1;
 189                 } else {
 190                         dbg("retry to connect %d", UDEVSEND_CONNECT_RETRY - loop);
 191                         tspec.tv_sec = 0;
 192                         tspec.tv_nsec = 100000000;  /* 100 millisec */
 193                         nanosleep(&tspec, NULL);
 194                 }
 195         }
 196
 197 close_and_exit:
 198         close(sock);
 199 exit:
 200         return retval;
 201 }