udevstart.c

   1 /*
   2  * quick and dirty way to populate a /dev directory
   3  *
   4  * Copyright (C) 2004 Harald Hoyer <harald@redhat.com>
   5  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   6  * Copyright (C) 2004-2006 Kay Sievers <kay@vrfy.org>
   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  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20  *
  21  */
  22
  23 #include <stdlib.h>
  24 #include <stddef.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <unistd.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30 #include <dirent.h>
  31 #include <signal.h>
  32 #include <syslog.h>
  33 #include <sys/wait.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36
  37 #include "udev.h"
  38 #include "udev_rules.h"
  39 #include "udev_selinux.h"
  40
  41 static const char *udev_run_str;
  42 static const char *udev_log_str;
  43 static struct udev_rules rules;
  44
  45 #ifdef USE_LOG
  46 void log_message(int priority, const char *format, ...)
  47 {
  48         va_list args;
  49
  50         if (priority > udev_log_priority)
  51                 return;
  52
  53         va_start(args, format);
  54         vsyslog(priority, format, args);
  55         va_end(args);
  56 }
  57 #endif
  58
  59 struct device {
  60         struct list_head node;
  61         char path[PATH_SIZE];
  62 };
  63
  64 /* sort files in lexical order */
  65 static int device_list_insert(const char *path, struct list_head *device_list)
  66 {
  67         struct device *loop_device;
  68         struct device *new_device;
  69         const char *devpath = &path[strlen(sysfs_path)];
  70
  71         dbg("insert: '%s'", devpath);
  72
  73         list_for_each_entry(loop_device, device_list, node) {
  74                 if (strcmp(loop_device->path, devpath) > 0) {
  75                         break;
  76                 }
  77         }
  78
  79         new_device = malloc(sizeof(struct device));
  80         if (new_device == NULL) {
  81                 dbg("error malloc");
  82                 return -ENOMEM;
  83         }
  84
  85         strlcpy(new_device->path, devpath, sizeof(new_device->path));
  86         list_add_tail(&new_device->node, &loop_device->node);
  87         dbg("add '%s'" , new_device->path);
  88         return 0;
  89 }
  90
  91 /* list of devices that we should run last due to any one of a number of reasons */
  92 static char *last_list[] = {
  93         "/block/dm",    /* on here because dm wants to have the block devices around before it */
  94         NULL,
  95 };
  96
  97 /* list of devices that we should run first due to any one of a number of reasons */
  98 static char *first_list[] = {
  99         "/class/mem",
 100         "/class/tty",
 101         NULL,
 102 };
 103
 104 static int add_device(const char *devpath)
 105 {
 106         struct sysfs_device *dev;
 107         struct udevice *udev;
 108         int retval = 0;
 109
 110         /* clear and set environment for next event */
 111         clearenv();
 112         setenv("ACTION", "add", 1);
 113         setenv("UDEV_START", "1", 1);
 114         if (udev_log_str)
 115                 setenv("UDEV_LOG", udev_log_str, 1);
 116         if (udev_run_str)
 117                 setenv("UDEV_RUN", udev_run_str, 1);
 118
 119         dev = sysfs_device_get(devpath);
 120         if (dev == NULL)
 121                 return -1;
 122
 123         udev = udev_device_init(NULL);
 124         if (udev == NULL)
 125                 return -1;
 126
 127         /* override built-in sysfs device */
 128         udev->dev = dev;
 129         strcpy(udev->action, "add");
 130
 131         if (strcmp(udev->dev->subsystem, "net") != 0) {
 132                 udev->devt = udev_device_get_devt(udev);
 133                 if (major(udev->devt) == 0)
 134                         return -1;
 135         }
 136
 137         dbg("add '%s'", udev->dev->devpath);
 138         setenv("DEVPATH", udev->dev->devpath, 1);
 139         setenv("SUBSYSTEM", udev->dev->subsystem, 1);
 140
 141         udev_rules_get_name(&rules, udev);
 142         if (udev->ignore_device) {
 143                 dbg("device event will be ignored");
 144                 goto exit;
 145         }
 146         if (udev->name[0] != '\0')
 147                 retval = udev_device_event(&rules, udev);
 148         else
 149                 info("device node creation supressed");
 150
 151         if (retval == 0 && udev_run)
 152                 udev_rules_run(udev);
 153
 154 exit:
 155         udev_device_cleanup(udev);
 156         return 0;
 157 }
 158
 159 static void exec_list(struct list_head *device_list)
 160 {
 161         struct device *loop_device;
 162         struct device *tmp_device;
 163         int i;
 164
 165         /* handle the "first" type devices first */
 166         list_for_each_entry_safe(loop_device, tmp_device, device_list, node) {
 167                 for (i = 0; first_list[i] != NULL; i++) {
 168                         if (strncmp(loop_device->path, first_list[i], strlen(first_list[i])) == 0) {
 169                                 add_device(loop_device->path);
 170                                 list_del(&loop_device->node);
 171                                 free(loop_device);
 172                                 break;
 173                         }
 174                 }
 175         }
 176
 177         /* handle the devices we are allowed to, excluding the "last" type devices */
 178         list_for_each_entry_safe(loop_device, tmp_device, device_list, node) {
 179                 int found = 0;
 180                 for (i = 0; last_list[i] != NULL; i++) {
 181                         if (strncmp(loop_device->path, last_list[i], strlen(last_list[i])) == 0) {
 182                                 found = 1;
 183                                 break;
 184                         }
 185                 }
 186                 if (found)
 187                         continue;
 188
 189                 add_device(loop_device->path);
 190                 list_del(&loop_device->node);
 191                 free(loop_device);
 192         }
 193
 194         /* handle the rest of the devices left over, if any */
 195         list_for_each_entry_safe(loop_device, tmp_device, device_list, node) {
 196                 add_device(loop_device->path);
 197                 list_del(&loop_device->node);
 198                 free(loop_device);
 199         }
 200 }
 201
 202 static int has_devt(const char *path)
 203 {
 204         char filename[PATH_SIZE];
 205         struct stat statbuf;
 206
 207         snprintf(filename, sizeof(filename), "%s/dev", path);
 208         filename[sizeof(filename)-1] = '\0';
 209
 210         if (stat(filename, &statbuf) == 0)
 211                 return 1;
 212
 213         return 0;
 214 }
 215
 216 static void udev_scan_block(struct list_head *device_list)
 217 {
 218         char base[PATH_SIZE];
 219         DIR *dir;
 220         struct dirent *dent;
 221
 222         snprintf(base, sizeof(base), "%s/block", sysfs_path);
 223         base[sizeof(base)-1] = '\0';
 224
 225         dir = opendir(base);
 226         if (dir != NULL) {
 227                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 228                         char dirname[PATH_SIZE];
 229                         DIR *dir2;
 230                         struct dirent *dent2;
 231
 232                         if (dent->d_name[0] == '.')
 233                                 continue;
 234
 235                         snprintf(dirname, sizeof(dirname), "%s/%s", base, dent->d_name);
 236                         dirname[sizeof(dirname)-1] = '\0';
 237                         if (has_devt(dirname))
 238                                 device_list_insert(dirname, device_list);
 239                         else
 240                                 continue;
 241
 242                         /* look for partitions */
 243                         dir2 = opendir(dirname);
 244                         if (dir2 != NULL) {
 245                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 246                                         char dirname2[PATH_SIZE];
 247
 248                                         if (dent2->d_name[0] == '.')
 249                                                 continue;
 250
 251                                         snprintf(dirname2, sizeof(dirname2), "%s/%s", dirname, dent2->d_name);
 252                                         dirname2[sizeof(dirname2)-1] = '\0';
 253
 254                                         if (has_devt(dirname2))
 255                                                 device_list_insert(dirname2, device_list);
 256                                 }
 257                                 closedir(dir2);
 258                         }
 259                 }
 260                 closedir(dir);
 261         }
 262 }
 263
 264 static void udev_scan_class(struct list_head *device_list)
 265 {
 266         char base[PATH_SIZE];
 267         DIR *dir;
 268         struct dirent *dent;
 269
 270         snprintf(base, sizeof(base), "%s/class", sysfs_path);
 271         base[sizeof(base)-1] = '\0';
 272
 273         dir = opendir(base);
 274         if (dir != NULL) {
 275                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 276                         char dirname[PATH_SIZE];
 277                         DIR *dir2;
 278                         struct dirent *dent2;
 279
 280                         if (dent->d_name[0] == '.')
 281                                 continue;
 282
 283                         snprintf(dirname, sizeof(dirname), "%s/%s", base, dent->d_name);
 284                         dirname[sizeof(dirname)-1] = '\0';
 285
 286                         dir2 = opendir(dirname);
 287                         if (dir2 != NULL) {
 288                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 289                                         char dirname2[PATH_SIZE];
 290
 291                                         if (dent2->d_name[0] == '.')
 292                                                 continue;
 293
 294                                         snprintf(dirname2, sizeof(dirname2), "%s/%s", dirname, dent2->d_name);
 295                                         dirname2[sizeof(dirname2)-1] = '\0';
 296
 297                                         if (has_devt(dirname2) || strcmp(dent->d_name, "net") == 0)
 298                                                 device_list_insert(dirname2, device_list);
 299                                 }
 300                                 closedir(dir2);
 301                         }
 302                 }
 303                 closedir(dir);
 304         }
 305 }
 306
 307 static void asmlinkage sig_handler(int signum)
 308 {
 309         switch (signum) {
 310                 case SIGALRM:
 311                         exit(1);
 312                 case SIGINT:
 313                 case SIGTERM:
 314                         exit(20 + signum);
 315         }
 316 }
 317
 318 int main(int argc, char *argv[], char *envp[])
 319 {
 320         LIST_HEAD(device_list);
 321         struct sigaction act;
 322
 323         logging_init("udevstart");
 324         udev_config_init();
 325         selinux_init();
 326         dbg("version %s", UDEV_VERSION);
 327
 328         udev_run_str = getenv("UDEV_RUN");
 329         udev_log_str = getenv("UDEV_LOG");
 330
 331         /* disable all logging if not explicitely requested */
 332         if (udev_log_str == NULL)
 333                 udev_log_priority = 0;
 334
 335         /* set signal handlers */
 336         memset(&act, 0x00, sizeof(act));
 337         act.sa_handler = (void (*) (int))sig_handler;
 338         sigemptyset (&act.sa_mask);
 339         act.sa_flags = 0;
 340         sigaction(SIGALRM, &act, NULL);
 341         sigaction(SIGINT, &act, NULL);
 342         sigaction(SIGTERM, &act, NULL);
 343
 344         /* trigger timeout to prevent hanging processes */
 345         alarm(UDEV_ALARM_TIMEOUT);
 346
 347         sysfs_init();
 348         udev_rules_init(&rules, 1);
 349
 350         udev_scan_class(&device_list);
 351         udev_scan_block(&device_list);
 352         exec_list(&device_list);
 353
 354         udev_rules_cleanup(&rules);
 355         sysfs_cleanup();
 356         selinux_exit();
 357         logging_close();
 358         return 0;
 359 }