udevstart.c

   1 /*
   2  * udevstart.c
   3  *
   4  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5  *
   6  * Quick and dirty way to populate a /dev with udev if your system
   7  * does not have access to a shell.  Based originally on a patch to udev
   8  * from Harald Hoyer <harald@redhat.com>
   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 <stdlib.h>
  26 #include <stddef.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29 #include <errno.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <sys/wait.h>
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35
  36 #include "logging.h"
  37 #include "udev_lib.h"
  38 #include "list.h"
  39
  40
  41 #ifdef LOG
  42 unsigned char logname[LOGNAME_SIZE];
  43 void log_message(int level, const char *format, ...)
  44 {
  45         va_list args;
  46
  47         va_start(args, format);
  48         vsyslog(level, format, args);
  49         va_end(args);
  50 }
  51 #endif
  52
  53
  54 #define MAX_PATHLEN             1024
  55 #define SYSBLOCK                "/sys/block"
  56 #define SYSCLASS                "/sys/class"
  57 #define UDEV_BIN                "/sbin/udev"
  58
  59 struct device {
  60         struct list_head list;
  61         char path[MAX_PATHLEN];
  62         char subsys[MAX_PATHLEN];
  63 };
  64
  65 /* sort files in lexical order */
  66 static int device_list_insert(char *path, char *subsystem, struct list_head *device_list)
  67 {
  68         struct device *loop_device;
  69         struct device *new_device;
  70
  71         list_for_each_entry(loop_device, device_list, list) {
  72                 if (strcmp(loop_device->path, path) > 0) {
  73                         break;
  74                 }
  75         }
  76
  77         new_device = malloc(sizeof(struct device));
  78         if (new_device == NULL) {
  79                 dbg("error malloc");
  80                 return -ENOMEM;
  81         }
  82
  83         strfieldcpy(new_device->path, path);
  84         strfieldcpy(new_device->subsys, subsystem);
  85         list_add_tail(&new_device->list, &loop_device->list);
  86         return 0;
  87 }
  88
  89 static void udev_exec(const char *path, const char* subsystem)
  90 {
  91         pid_t pid;
  92         char action[] = "ACTION=add";
  93         char devpath[MAX_PATHLEN];
  94         char nosleep[] = "UDEV_NO_SLEEP=1";
  95         char *env[] = { action, devpath, nosleep, NULL };
  96
  97         strcpy(devpath, "DEVPATH=");
  98         strfieldcat(devpath, path);
  99
 100         pid = fork();
 101         switch (pid) {
 102         case 0:
 103                 /* child */
 104                 execle(UDEV_BIN, "udev", subsystem, NULL, env);
 105                 dbg("exec of child failed");
 106                 exit(1);
 107                 break;
 108         case -1:
 109                 dbg("fork of child failed");
 110                 break;
 111         default:
 112                 wait(NULL);
 113         }
 114 }
 115
 116 /* list of devices that we should run last due to any one of a number of reasons */
 117 static char *last_list[] = {
 118         "/block/dm",    /* on here because dm wants to have the block devices around before it */
 119         NULL,
 120 };
 121
 122 static void exec_list(struct list_head *device_list)
 123 {
 124         struct device *loop_device;
 125         struct device *tmp_device;
 126
 127         /* handle the devices we are allowed to, excluding the "last" type devices */
 128         list_for_each_entry_safe(loop_device, tmp_device, device_list, list) {
 129                 int found = 0;
 130                 int i;
 131                 for (i=0; last_list[i] != NULL; i++) {
 132                         if (strncmp(loop_device->path, last_list[i], strlen(last_list[i])) == 0) {
 133                                 found = 1;
 134                                 break;
 135                         }
 136                 }
 137                 if (found)
 138                         continue;
 139
 140                 udev_exec(loop_device->path, loop_device->subsys);
 141                 list_del(&loop_device->list);
 142                 free(loop_device);
 143         }
 144
 145         /* handle the rest of the devices left over, if any */
 146         list_for_each_entry_safe(loop_device, tmp_device, device_list, list) {
 147                 udev_exec(loop_device->path, loop_device->subsys);
 148                 list_del(&loop_device->list);
 149                 free(loop_device);
 150         }
 151 }
 152
 153 static void udev_scan_block(void)
 154 {
 155         DIR *dir;
 156         struct dirent *dent;
 157         LIST_HEAD(device_list);
 158
 159         dir = opendir(SYSBLOCK);
 160         if (dir != NULL) {
 161                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 162                         char dirname[MAX_PATHLEN];
 163                         DIR *dir2;
 164                         struct dirent *dent2;
 165
 166                         if ((strcmp(dent->d_name, ".") == 0) ||
 167                             (strcmp(dent->d_name, "..") == 0))
 168                                 continue;
 169
 170                         snprintf(dirname, MAX_PATHLEN, "/block/%s", dent->d_name);
 171                         dirname[MAX_PATHLEN-1] = '\0';
 172                         device_list_insert(dirname, "block", &device_list);
 173
 174                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSBLOCK, dent->d_name);
 175                         dir2 = opendir(dirname);
 176                         if (dir2 != NULL) {
 177                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 178                                         char dirname2[MAX_PATHLEN];
 179                                         DIR *dir3;
 180                                         struct dirent *dent3;
 181
 182                                         if ((strcmp(dent2->d_name, ".") == 0) ||
 183                                             (strcmp(dent2->d_name, "..") == 0))
 184                                                 continue;
 185
 186                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 187                                         dirname2[MAX_PATHLEN-1] = '\0';
 188
 189                                         dir3 = opendir(dirname2);
 190                                         if (dir3 != NULL) {
 191                                                 for (dent3 = readdir(dir3); dent3 != NULL; dent3 = readdir(dir3)) {
 192                                                         char filename[MAX_PATHLEN];
 193
 194                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 195                                                                 snprintf(filename, MAX_PATHLEN, "/block/%s/%s",
 196                                                                          dent->d_name, dent2->d_name);
 197                                                                 filename[MAX_PATHLEN-1] = '\0';
 198                                                                 device_list_insert(filename, "block", &device_list);
 199                                                         }
 200                                                 }
 201                                                 closedir(dir3);
 202                                         }
 203                                 }
 204                                 closedir(dir2);
 205                         }
 206                 }
 207                 closedir(dir);
 208         }
 209
 210         exec_list(&device_list);
 211 }
 212
 213 static void udev_scan_class(void)
 214 {
 215         DIR *dir;
 216         struct dirent *dent;
 217         LIST_HEAD(device_list);
 218
 219         dir = opendir(SYSCLASS);
 220         if (dir != NULL) {
 221                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 222                         char dirname[MAX_PATHLEN];
 223                         DIR *dir2;
 224                         struct dirent *dent2;
 225
 226                         if ((strcmp(dent->d_name, ".") == 0) ||
 227                             (strcmp(dent->d_name, "..") == 0))
 228                                 continue;
 229
 230                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSCLASS, dent->d_name);
 231                         dirname[MAX_PATHLEN] = '\0';
 232                         dir2 = opendir(dirname);
 233                         if (dir2 != NULL) {
 234                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 235                                         char dirname2[MAX_PATHLEN-1];
 236                                         DIR *dir3;
 237                                         struct dirent *dent3;
 238
 239                                         if ((strcmp(dent2->d_name, ".") == 0) ||
 240                                             (strcmp(dent2->d_name, "..") == 0))
 241                                                 continue;
 242
 243                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 244                                         dirname2[MAX_PATHLEN-1] = '\0';
 245
 246                                         dir3 = opendir(dirname2);
 247                                         if (dir3 != NULL) {
 248                                                 for (dent3 = readdir(dir3); dent3 != NULL; dent3 = readdir(dir3)) {
 249                                                         char filename[MAX_PATHLEN];
 250
 251                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 252                                                                 snprintf(filename, MAX_PATHLEN, "/class/%s/%s",
 253                                                                          dent->d_name, dent2->d_name);
 254                                                                 filename[MAX_PATHLEN-1] = '\0';
 255                                                                 device_list_insert(filename, dent->d_name, &device_list);
 256                                                         }
 257                                                 }
 258                                                 closedir(dir3);
 259                                         }
 260                                 }
 261                                 closedir(dir2);
 262                         }
 263                 }
 264                 closedir(dir);
 265         }
 266
 267         exec_list(&device_list);
 268 }
 269
 270 int main(int argc, char *argv[], char *envp[])
 271 {
 272         init_logging("udevstart");
 273
 274         udev_scan_class();
 275         udev_scan_block();
 276
 277         return 0;
 278 }