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 /* global variables */
  40 char **main_argv;
  41 char **main_envp;
  42
  43 /* local variables */
  44 static int is_udevstart;
  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 SIGINT:
  65                 case SIGTERM:
  66                         udevdb_exit();
  67                         exit(20 + signum);
  68                 default:
  69                         dbg("unhandled signal %d", signum);
  70         }
  71 }
  72
  73 static char *subsystem_blacklist[] = {
  74         "scsi_host",
  75         "scsi_device",
  76         "usb_host",
  77         "pci_bus",
  78         "pcmcia_socket",
  79         ""
  80 };
  81
  82 int __udev_hotplug(char *action, const char *devpath, const char *subsystem)
  83 {
  84         int retval = -EINVAL;
  85         int i;
  86         struct sigaction act;
  87         const int nofake = 0;
  88
  89         dbg("looking at '%s'", devpath);
  90
  91         /* we only care about class devices and block stuff */
  92         if (!strstr(devpath, "class") &&
  93             !strstr(devpath, "block")) {
  94                 dbg("not a block or class device");
  95                 goto exit;
  96         }
  97
  98         i = 0;
  99         while (subsystem_blacklist[i][0] != '\0') {
 100                 if (strcmp(subsystem, subsystem_blacklist[i]) == 0) {
 101                         dbg("don't care about '%s' devices", subsystem);
 102                         goto exit;
 103                 }
 104                 i++;
 105         }
 106
 107         /* initialize udev database */
 108         retval = udevdb_init(UDEVDB_DEFAULT);
 109         if (retval != 0) {
 110                 dbg("unable to initialize database");
 111                 goto exit;
 112         }
 113
 114         /* set signal handlers */
 115         act.sa_handler = sig_handler;
 116         sigemptyset (&act.sa_mask);
 117         act.sa_flags = SA_RESTART;
 118         sigaction(SIGINT, &act, NULL);
 119         sigaction(SIGTERM, &act, NULL);
 120
 121         if (strcmp(action, "add") == 0) {
 122                 /* Already done. */
 123                 if (!is_udevstart)
 124                         namedev_init();
 125                 retval = udev_add_device(devpath, subsystem, nofake);
 126                 goto action_done;
 127         }
 128
 129         if (strcmp(action, "remove") == 0) {
 130                 retval = udev_remove_device(devpath, subsystem);
 131                 goto action_done;
 132         }
 133
 134         dbg("unknown action '%s'", action);
 135         retval = -EINVAL;
 136
 137 action_done:
 138         udevdb_exit();
 139
 140 exit:
 141         return retval;
 142 }
 143
 144 static int udev_hotplug(void)
 145 {
 146         char *action;
 147         char *devpath;
 148         char *subsystem;
 149
 150         action = get_action();
 151         if (!action) {
 152                 dbg("no action?");
 153                 return -EINVAL;
 154         }
 155
 156         devpath = get_devpath();
 157         if (!devpath) {
 158                 dbg("no devpath?");
 159                 return -EINVAL;
 160         }
 161
 162         /* skip blacklisted subsystems */
 163         subsystem = get_subsystem(main_argv[1]);
 164         if (!subsystem) {
 165                 dbg("no subsystem?");
 166                 return -EINVAL;
 167         }
 168
 169         return __udev_hotplug(action, devpath, subsystem);
 170 }
 171
 172 int main(int argc, char *argv[], char *envp[])
 173 {
 174         main_argv = argv;
 175         main_envp = envp;
 176
 177         if (strstr(argv[0], "udevstart"))
 178                 is_udevstart = 1;
 179
 180         /* initialize our configuration */
 181         udev_init_config();
 182
 183         dbg("version %s", UDEV_VERSION);
 184
 185         if (is_udevstart) {
 186                 namedev_init();
 187                 return udev_start();
 188         } else
 189                 return udev_hotplug();
 190 }