udev.c

   1 /*
   2  * udev.c
   3  *
   4  * Userspace devfs
   5  *
   6  * Copyright (C) 2003,2004 Greg Kroah-Hartman <greg@kroah.com>
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stdio.h>
  24 #include <stddef.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <errno.h>
  29 #include <signal.h>
  30
  31 #include "libsysfs/sysfs/libsysfs.h"
  32 #include "udev.h"
  33 #include "udev_lib.h"
  34 #include "udev_version.h"
  35 #include "logging.h"
  36 #include "namedev.h"
  37 #include "udevdb.h"
  38
  39 /* timeout flag for udevdb */
  40 extern sig_atomic_t gotalarm;
  41
  42 /* global variables */
  43 char **main_argv;
  44 char **main_envp;
  45
  46 #ifdef LOG
  47 unsigned char logname[LOGNAME_SIZE];
  48 void log_message(int level, const char *format, ...)
  49 {
  50         va_list args;
  51
  52         if (!udev_log)
  53                 return;
  54
  55         va_start(args, format);
  56         vsyslog(level, format, args);
  57         va_end(args);
  58 }
  59 #endif
  60
  61 asmlinkage static void sig_handler(int signum)
  62 {
  63         switch (signum) {
  64                 case SIGALRM:
  65                         gotalarm = 1;
  66                         info("error: timeout reached, event probably not handled correctly");
  67                         break;
  68                 case SIGINT:
  69                 case SIGTERM:
  70                         udevdb_exit();
  71                         exit(20 + signum);
  72                 default:
  73                         dbg("unhandled signal %d", signum);
  74         }
  75 }
  76
  77 static char *subsystem_blacklist[] = {
  78         "scsi_host",
  79         "scsi_device",
  80         "usb_host",
  81         "pci_bus",
  82         "pcmcia_socket",
  83         ""
  84 };
  85
  86 int main(int argc, char *argv[], char *envp[])
  87 {
  88         main_argv = argv;
  89         main_envp = envp;
  90         struct sigaction act;
  91         char *action;
  92         char *devpath = "";
  93         char *subsystem = "";
  94         int i;
  95         int retval = -EINVAL;
  96         enum {
  97                 ADD,
  98                 REMOVE,
  99                 UDEVSTART,
 100         } act_type;
 101
 102         dbg("version %s", UDEV_VERSION);
 103
 104         init_logging("udev");
 105
 106         udev_init_config();
 107
 108         if (strstr(argv[0], "udevstart")) {
 109                 act_type = UDEVSTART;
 110         } else {
 111                 action = get_action();
 112                 if (!action) {
 113                         dbg("no action?");
 114                         goto exit;
 115                 }
 116                 if (strcmp(action, "add") == 0) {
 117                         act_type = ADD;
 118                 } else if (strcmp(action, "remove") == 0) {
 119                         act_type = REMOVE;
 120                 } else {
 121                         dbg("unknown action '%s'", action);
 122                         goto exit;
 123                 }
 124
 125                 devpath = get_devpath();
 126                 if (!devpath) {
 127                         dbg("no devpath?");
 128                         goto exit;
 129                 }
 130                 dbg("looking at '%s'", devpath);
 131
 132                 /* we only care about class devices and block stuff */
 133                 if (!strstr(devpath, "class") && !strstr(devpath, "block")) {
 134                         dbg("not a block or class device");
 135                         goto exit;
 136                 }
 137
 138                 subsystem = get_subsystem(main_argv[1]);
 139                 if (!subsystem) {
 140                         dbg("no subsystem?");
 141                         goto exit;
 142                 }
 143
 144                 /* skip blacklisted subsystems */
 145                 i = 0;
 146                 while (subsystem_blacklist[i][0] != '\0') {
 147                         if (strcmp(subsystem, subsystem_blacklist[i]) == 0) {
 148                                 dbg("don't care about '%s' devices", subsystem);
 149                                 goto exit;
 150                         }
 151                         i++;
 152                 }
 153         }
 154
 155         /* set signal handlers */
 156         act.sa_handler = (void (*) (int))sig_handler;
 157
 158         sigemptyset (&act.sa_mask);
 159         /* alarm must interrupt syscalls*/
 160         sigaction(SIGALRM, &act, NULL);
 161         sigaction(SIGINT, &act, NULL);
 162         sigaction(SIGTERM, &act, NULL);
 163
 164         /* trigger timout to interrupt blocking syscalls */
 165         alarm(ALARM_TIMEOUT);
 166
 167         /* initialize udev database */
 168         if (udevdb_init(UDEVDB_DEFAULT) != 0)
 169                 info("error: unable to initialize database, continuing without database");
 170
 171         switch(act_type) {
 172         case UDEVSTART:
 173                 dbg("udevstart");
 174                 namedev_init();
 175                 udev_sleep = 0;
 176                 retval = udev_start();
 177                 break;
 178         case ADD:
 179                 dbg("udev add");
 180                 namedev_init();
 181                 retval = udev_add_device(devpath, subsystem, NOFAKE);
 182                 break;
 183         case REMOVE:
 184                 dbg("udev remove");
 185                 retval = udev_remove_device(devpath, subsystem);
 186         }
 187
 188         udevdb_exit();
 189
 190 exit:
 191         return retval;
 192 }