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 <stddef.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35 #include <time.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 int build_hotplugmsg(struct hotplug_msg *msg, char *action,
  57                             char *devpath, char *subsystem, int seqnum)
  58 {
  59         memset(msg, 0x00, sizeof(*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         return sizeof(struct hotplug_msg);
  66 }
  67
  68 static int start_daemon(void)
  69 {
  70         pid_t pid;
  71         pid_t child_pid;
  72
  73         pid = fork();
  74         switch (pid) {
  75         case 0:
  76                 /* helper child */
  77                 child_pid = fork();
  78                 switch (child_pid) {
  79                 case 0:
  80                         /* daemon */
  81                         setsid();
  82                         chdir("/");
  83                         execl(UDEVD_BIN, "udevd", NULL);
  84                         dbg("exec of daemon failed");
  85                         exit(1);
  86                 case -1:
  87                         dbg("fork of daemon failed");
  88                         return -1;
  89                 default:
  90                         exit(0);
  91                 }
  92                 break;
  93         case -1:
  94                 dbg("fork of helper failed");
  95                 return -1;
  96         default:
  97                 wait(NULL);
  98         }
  99         return 0;
 100 }
 101
 102 int main(int argc, char* argv[])
 103 {
 104         struct hotplug_msg msg;
 105         char *action;
 106         char *devpath;
 107         char *subsystem;
 108         char *seqnum;
 109         int seq;
 110         int retval = 1;
 111         int size;
 112         int loop;
 113         struct timespec tspec;
 114         int sock;
 115         struct sockaddr_un saddr;
 116         socklen_t addrlen;
 117         int started_daemon = 0;
 118
 119 #ifdef DEBUG
 120         init_logging("udevsend");
 121 #endif
 122         dbg("version %s", UDEV_VERSION);
 123
 124         subsystem = get_subsystem(argv[1]);
 125         if (subsystem == NULL) {
 126                 dbg("no subsystem");
 127                 goto exit;
 128         }
 129         dbg("subsystem = '%s'", subsystem);
 130
 131         devpath = get_devpath();
 132         if (devpath == NULL) {
 133                 dbg("no devpath");
 134                 goto exit;
 135         }
 136         dbg("DEVPATH = '%s'", devpath);
 137
 138         action = get_action();
 139         if (action == NULL) {
 140                 dbg("no action");
 141                 goto exit;
 142         }
 143         dbg("ACTION = '%s'", action);
 144
 145         seqnum = get_seqnum();
 146         if (seqnum == NULL)
 147                 seq = -1;
 148         else
 149                 seq = atoi(seqnum);
 150         dbg("SEQNUM = '%d'", seq);
 151
 152         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 153         if (sock == -1) {
 154                 dbg("error getting socket");
 155                 goto exit;
 156         }
 157
 158         memset(&saddr, 0x00, sizeof(saddr));
 159         saddr.sun_family = AF_LOCAL;
 160         /* use abstract namespace for socket path */
 161         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 162         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 163
 164         size = build_hotplugmsg(&msg, action, devpath, subsystem, seq);
 165
 166         /* If we can't send, try to start daemon and resend message */
 167         loop = UDEVSEND_CONNECT_RETRY;
 168         while (loop--) {
 169                 retval = sendto(sock, &msg, size, 0, (struct sockaddr *)&saddr, addrlen);
 170                 if (retval != -1) {
 171                         retval = 0;
 172                         goto close_and_exit;
 173                 }
 174
 175                 if (errno != ECONNREFUSED) {
 176                         dbg("error sending message");
 177                         goto close_and_exit;
 178                 }
 179
 180                 if (!started_daemon) {
 181                         dbg("connect failed, try starting daemon...");
 182                         retval = start_daemon();
 183                         if (retval) {
 184                                 dbg("error starting daemon");
 185                                 goto exit;
 186                         }
 187
 188                         dbg("daemon started");
 189                         started_daemon = 1;
 190                 } else {
 191                         dbg("retry to connect %d", UDEVSEND_CONNECT_RETRY - loop);
 192                         tspec.tv_sec = 0;
 193                         tspec.tv_nsec = 100000000;  /* 100 millisec */
 194                         nanosleep(&tspec, NULL);
 195                 }
 196         }
 197
 198 close_and_exit:
 199         close(sock);
 200 exit:
 201         return retval;
 202 }