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_version.h"
  40 #include "udevd.h"
  41 #include "logging.h"
  42
  43 #ifdef LOG
  44 unsigned char logname[42];
  45 void log_message (int level, const char *format, ...)
  46 {
  47         va_list args;
  48
  49         va_start(args, format);
  50         vsyslog(level, format, args);
  51         va_end(args);
  52 }
  53 #endif
  54
  55 static inline char *get_action(void)
  56 {
  57         char *action;
  58
  59         action = getenv("ACTION");
  60         return action;
  61 }
  62
  63 static inline char *get_devpath(void)
  64 {
  65         char *devpath;
  66
  67         devpath = getenv("DEVPATH");
  68         return devpath;
  69 }
  70
  71 static inline char *get_seqnum(void)
  72 {
  73         char *seqnum;
  74
  75         seqnum = getenv("SEQNUM");
  76         return seqnum;
  77 }
  78
  79 static int build_hotplugmsg(struct hotplug_msg *msg, char *action,
  80                             char *devpath, char *subsystem, int seqnum)
  81 {
  82         memset(msg, 0x00, sizeof(*msg));
  83         strfieldcpy(msg->magic, UDEV_MAGIC);
  84         msg->seqnum = seqnum;
  85         strfieldcpy(msg->action, action);
  86         strfieldcpy(msg->devpath, devpath);
  87         strfieldcpy(msg->subsystem, subsystem);
  88         return sizeof(struct hotplug_msg);
  89 }
  90
  91 static int start_daemon(void)
  92 {
  93         pid_t pid;
  94         pid_t child_pid;
  95
  96         pid = fork();
  97         switch (pid) {
  98         case 0:
  99                 /* helper child */
 100                 child_pid = fork();
 101                 switch (child_pid) {
 102                 case 0:
 103                         /* daemon */
 104                         setsid();
 105                         chdir("/");
 106                         execl(UDEVD_BIN, "udevd", NULL);
 107                         dbg("exec of daemon failed");
 108                         exit(1);
 109                 case -1:
 110                         dbg("fork of daemon failed");
 111                         return -1;
 112                 default:
 113                         exit(0);
 114                 }
 115                 break;
 116         case -1:
 117                 dbg("fork of helper failed");
 118                 return -1;
 119         default:
 120                 wait(NULL);
 121         }
 122         return 0;
 123 }
 124
 125 int main(int argc, char* argv[])
 126 {
 127         struct hotplug_msg msg;
 128         char *action;
 129         char *devpath;
 130         char *subsystem;
 131         char *seqnum;
 132         int seq;
 133         int retval = 1;
 134         int size;
 135         int loop;
 136         struct timespec tspec;
 137         int sock;
 138         struct sockaddr_un saddr;
 139         socklen_t addrlen;
 140         int started_daemon = 0;
 141
 142 #ifdef DEBUG
 143         init_logging("udevsend");
 144 #endif
 145         dbg("version %s", UDEV_VERSION);
 146
 147         subsystem = argv[1];
 148         if (subsystem == NULL) {
 149                 dbg("no subsystem");
 150                 goto exit;
 151         }
 152         dbg("subsystem = '%s'", subsystem);
 153
 154         devpath = get_devpath();
 155         if (devpath == NULL) {
 156                 dbg("no devpath");
 157                 goto exit;
 158         }
 159         dbg("DEVPATH = '%s'", devpath);
 160
 161         action = get_action();
 162         if (action == NULL) {
 163                 dbg("no action");
 164                 goto exit;
 165         }
 166         dbg("ACTION = '%s'", action);
 167
 168         seqnum = get_seqnum();
 169         if (seqnum == NULL)
 170                 seq = -1;
 171         else
 172                 seq = atoi(seqnum);
 173         dbg("SEQNUM = '%d'", seq);
 174
 175         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 176         if (sock == -1) {
 177                 dbg("error getting socket");
 178                 goto exit;
 179         }
 180
 181         memset(&saddr, 0x00, sizeof(saddr));
 182         saddr.sun_family = AF_LOCAL;
 183         /* use abstract namespace for socket path */
 184         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 185         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 186
 187         size = build_hotplugmsg(&msg, action, devpath, subsystem, seq);
 188
 189         /* If we can't send, try to start daemon and resend message */
 190         loop = UDEVSEND_CONNECT_RETRY;
 191         while (loop--) {
 192                 retval = sendto(sock, &msg, size, 0, (struct sockaddr *)&saddr, addrlen);
 193                 if (retval != -1) {
 194                         retval = 0;
 195                         goto close_and_exit;
 196                 }
 197
 198                 if (errno != ECONNREFUSED) {
 199                         dbg("error sending message");
 200                         goto close_and_exit;
 201                 }
 202
 203                 if (!started_daemon) {
 204                         dbg("connect failed, try starting daemon...");
 205                         retval = start_daemon();
 206                         if (retval) {
 207                                 dbg("error starting daemon");
 208                                 goto exit;
 209                         }
 210
 211                         dbg("daemon started");
 212                         started_daemon = 1;
 213                 } else {
 214                         dbg("retry to connect %d", UDEVSEND_CONNECT_RETRY - loop);
 215                         tspec.tv_sec = 0;
 216                         tspec.tv_nsec = 100000000;  /* 100 millisec */
 217                         nanosleep(&tspec, NULL);
 218                 }
 219         }
 220
 221 close_and_exit:
 222         close(sock);
 223 exit:
 224         return retval;
 225 }