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 #define _KLIBC_HAS_ARCH_SIG_ATOMIC_T
  24 #include <stdio.h>
  25 #include <stddef.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <errno.h>
  30 #include <signal.h>
  31
  32 #include "libsysfs/sysfs/libsysfs.h"
  33 #include "udev.h"
  34 #include "udev_lib.h"
  35 #include "udev_version.h"
  36 #include "logging.h"
  37 #include "namedev.h"
  38 #include "udevdb.h"
  39
  40 /* timeout flag for udevdb */
  41 extern sig_atomic_t gotalarm;
  42
  43 /* global variables */
  44 char **main_argv;
  45 char **main_envp;
  46
  47 #ifdef LOG
  48 unsigned char logname[LOGNAME_SIZE];
  49 void log_message(int level, const char *format, ...)
  50 {
  51         va_list args;
  52
  53         if (!udev_log)
  54                 return;
  55
  56         va_start(args, format);
  57         vsyslog(level, format, args);
  58         va_end(args);
  59 }
  60 #endif
  61
  62 static void asmlinkage sig_handler(int signum)
  63 {
  64         switch (signum) {
  65                 case SIGALRM:
  66                         gotalarm = 1;
  67                         info("error: timeout reached, event probably not handled correctly");
  68                         break;
  69                 case SIGINT:
  70                 case SIGTERM:
  71                         udevdb_exit();
  72                         exit(20 + signum);
  73                 default:
  74                         dbg("unhandled signal %d", signum);
  75         }
  76 }
  77
  78 /* list of subsystems we don't care about. not listing such systems here
  79  * is not critical, but it makes it faster as we don't look for the "dev" file
  80  */
  81 static int subsystem_without_dev(const char *subsystem)
  82 {
  83         char *subsystem_blacklist[] = {
  84                 "scsi_host",
  85                 "scsi_device",
  86                 "usb_host",
  87                 "pci_bus",
  88                 "pcmcia_socket",
  89                 "bluetooth",
  90                 "i2c-adapter",
  91                 "pci_bus",
  92                 "ieee1394",
  93                 "ieee1394_host",
  94                 "ieee1394_node",
  95                 NULL
  96         };
  97         char **subsys;
  98
  99         for (subsys = subsystem_blacklist; *subsys != NULL; subsys++) {
 100                 if (strcmp(subsystem, *subsys) == 0)
 101                         return 1;
 102         }
 103
 104         return 0;
 105 }
 106
 107 int main(int argc, char *argv[], char *envp[])
 108 {
 109         struct sigaction act;
 110         char *action;
 111         char *devpath = "";
 112         char *subsystem = "";
 113         int retval = -EINVAL;
 114         enum {
 115                 ADD,
 116                 REMOVE,
 117                 UDEVSTART,
 118         } act_type;
 119
 120         dbg("version %s", UDEV_VERSION);
 121
 122         main_argv = argv;
 123         main_envp = envp;
 124
 125         init_logging("udev");
 126
 127         udev_init_config();
 128
 129         if (strstr(argv[0], "udevstart")) {
 130                 act_type = UDEVSTART;
 131         } else {
 132                 action = get_action();
 133                 if (!action) {
 134                         dbg("no action?");
 135                         goto exit;
 136                 }
 137                 if (strcmp(action, "add") == 0) {
 138                         act_type = ADD;
 139                 } else if (strcmp(action, "remove") == 0) {
 140                         act_type = REMOVE;
 141                 } else {
 142                         dbg("unknown action '%s'", action);
 143                         goto exit;
 144                 }
 145
 146                 devpath = get_devpath();
 147                 if (!devpath) {
 148                         dbg("no devpath?");
 149                         goto exit;
 150                 }
 151                 dbg("looking at '%s'", devpath);
 152
 153                 /* we only care about class devices and block stuff */
 154                 if (!strstr(devpath, "class") && !strstr(devpath, "block")) {
 155                         dbg("not a block or class device");
 156                         goto exit;
 157                 }
 158
 159                 subsystem = get_subsystem(main_argv[1]);
 160                 if (!subsystem) {
 161                         dbg("no subsystem?");
 162                         goto exit;
 163                 }
 164
 165                 /* skip blacklisted subsystems */
 166                 if (subsystem_without_dev(subsystem)) {
 167                         dbg("don't care about '%s' devices", subsystem);
 168                         exit(0);
 169                 };
 170         }
 171
 172         /* set signal handlers */
 173         act.sa_handler = (void (*) (int))sig_handler;
 174         sigemptyset (&act.sa_mask);
 175         /* alarm must not restart syscalls*/
 176         sigaction(SIGALRM, &act, NULL);
 177         sigaction(SIGINT, &act, NULL);
 178         sigaction(SIGTERM, &act, NULL);
 179
 180         /* trigger timout to interrupt blocking syscalls */
 181         alarm(ALARM_TIMEOUT);
 182
 183         /* initialize udev database */
 184         if (udevdb_init(UDEVDB_DEFAULT) != 0)
 185                 info("error: unable to initialize database, continuing without database");
 186
 187         switch(act_type) {
 188         case UDEVSTART:
 189                 dbg("udevstart");
 190                 namedev_init();
 191                 retval = udev_start();
 192                 break;
 193         case ADD:
 194                 dbg("udev add");
 195                 namedev_init();
 196                 retval = udev_add_device(devpath, subsystem, NOFAKE);
 197                 break;
 198         case REMOVE:
 199                 dbg("udev remove");
 200                 retval = udev_remove_device(devpath, subsystem);
 201         }
 202
 203         udevdb_exit();
 204
 205 exit:
 206         return retval;
 207 }