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 #include "udev.h"
  40
  41
  42 #define MAX_PATHLEN             1024
  43 #define SYSBLOCK                "/sys/block"
  44 #define SYSCLASS                "/sys/class"
  45
  46 struct device {
  47         struct list_head list;
  48         char path[MAX_PATHLEN];
  49         char subsys[MAX_PATHLEN];
  50 };
  51
  52 /* sort files in lexical order */
  53 static int device_list_insert(char *path, char *subsystem, struct list_head *device_list)
  54 {
  55         struct device *loop_device;
  56         struct device *new_device;
  57
  58         list_for_each_entry(loop_device, device_list, list) {
  59                 if (strcmp(loop_device->path, path) > 0) {
  60                         break;
  61                 }
  62         }
  63
  64         new_device = malloc(sizeof(struct device));
  65         if (new_device == NULL) {
  66                 dbg("error malloc");
  67                 return -ENOMEM;
  68         }
  69
  70         strfieldcpy(new_device->path, path);
  71         strfieldcpy(new_device->subsys, subsystem);
  72         list_add_tail(&new_device->list, &loop_device->list);
  73         dbg("add '%s' from subsys '%s'", new_device->path, new_device->subsys);
  74         return 0;
  75 }
  76
  77 /* list of devices that we should run last due to any one of a number of reasons */
  78 static char *last_list[] = {
  79         "/block/dm",    /* on here because dm wants to have the block devices around before it */
  80         NULL,
  81 };
  82
  83 static void exec_list(struct list_head *device_list)
  84 {
  85         struct device *loop_device;
  86         struct device *tmp_device;
  87
  88         /* handle the devices we are allowed to, excluding the "last" type devices */
  89         list_for_each_entry_safe(loop_device, tmp_device, device_list, list) {
  90                 int found = 0;
  91                 int i;
  92                 for (i=0; last_list[i] != NULL; i++) {
  93                         if (strncmp(loop_device->path, last_list[i], strlen(last_list[i])) == 0) {
  94                                 found = 1;
  95                                 break;
  96                         }
  97                 }
  98                 if (found)
  99                         continue;
 100
 101                 udev_add_device(loop_device->path, loop_device->subsys, NOFAKE);
 102                 list_del(&loop_device->list);
 103                 free(loop_device);
 104         }
 105
 106         /* handle the rest of the devices left over, if any */
 107         list_for_each_entry_safe(loop_device, tmp_device, device_list, list) {
 108                 udev_add_device(loop_device->path, loop_device->subsys, NOFAKE);
 109                 list_del(&loop_device->list);
 110                 free(loop_device);
 111         }
 112 }
 113
 114 static void udev_scan_block(void)
 115 {
 116         DIR *dir;
 117         struct dirent *dent;
 118         LIST_HEAD(device_list);
 119
 120         dir = opendir(SYSBLOCK);
 121         if (dir != NULL) {
 122                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 123                         char dirname[MAX_PATHLEN];
 124                         DIR *dir2;
 125                         struct dirent *dent2;
 126
 127                         if ((strcmp(dent->d_name, ".") == 0) ||
 128                             (strcmp(dent->d_name, "..") == 0))
 129                                 continue;
 130
 131                         snprintf(dirname, MAX_PATHLEN, "/block/%s", dent->d_name);
 132                         dirname[MAX_PATHLEN-1] = '\0';
 133                         device_list_insert(dirname, "block", &device_list);
 134
 135                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSBLOCK, dent->d_name);
 136                         dir2 = opendir(dirname);
 137                         if (dir2 != NULL) {
 138                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 139                                         char dirname2[MAX_PATHLEN];
 140                                         DIR *dir3;
 141                                         struct dirent *dent3;
 142
 143                                         if ((strcmp(dent2->d_name, ".") == 0) ||
 144                                             (strcmp(dent2->d_name, "..") == 0))
 145                                                 continue;
 146
 147                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 148                                         dirname2[MAX_PATHLEN-1] = '\0';
 149
 150                                         dir3 = opendir(dirname2);
 151                                         if (dir3 != NULL) {
 152                                                 for (dent3 = readdir(dir3); dent3 != NULL; dent3 = readdir(dir3)) {
 153                                                         char filename[MAX_PATHLEN];
 154
 155                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 156                                                                 snprintf(filename, MAX_PATHLEN, "/block/%s/%s",
 157                                                                          dent->d_name, dent2->d_name);
 158                                                                 filename[MAX_PATHLEN-1] = '\0';
 159                                                                 device_list_insert(filename, "block", &device_list);
 160                                                         }
 161                                                 }
 162                                                 closedir(dir3);
 163                                         }
 164                                 }
 165                                 closedir(dir2);
 166                         }
 167                 }
 168                 closedir(dir);
 169         }
 170
 171         exec_list(&device_list);
 172 }
 173
 174 static void udev_scan_class(void)
 175 {
 176         DIR *dir;
 177         struct dirent *dent;
 178         LIST_HEAD(device_list);
 179
 180         dir = opendir(SYSCLASS);
 181         if (dir != NULL) {
 182                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 183                         char dirname[MAX_PATHLEN];
 184                         DIR *dir2;
 185                         struct dirent *dent2;
 186
 187                         if ((strcmp(dent->d_name, ".") == 0) ||
 188                             (strcmp(dent->d_name, "..") == 0))
 189                                 continue;
 190
 191                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSCLASS, dent->d_name);
 192                         dirname[MAX_PATHLEN-1] = '\0';
 193                         dir2 = opendir(dirname);
 194                         if (dir2 != NULL) {
 195                                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
 196                                         char dirname2[MAX_PATHLEN-1];
 197                                         DIR *dir3;
 198                                         struct dirent *dent3;
 199
 200                                         if ((strcmp(dent2->d_name, ".") == 0) ||
 201                                             (strcmp(dent2->d_name, "..") == 0))
 202                                                 continue;
 203
 204                                         /* pass the net class as it is */
 205                                         if (strcmp(dent->d_name, "net") == 0) {
 206                                                 snprintf(dirname2, MAX_PATHLEN, "/class/net/%s", dent2->d_name);
 207                                                 device_list_insert(dirname2, "net", &device_list);
 208                                                 continue;
 209                                         }
 210
 211                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 212                                         dirname2[MAX_PATHLEN-1] = '\0';
 213                                         dir3 = opendir(dirname2);
 214                                         if (dir3 != NULL) {
 215                                                 for (dent3 = readdir(dir3); dent3 != NULL; dent3 = readdir(dir3)) {
 216                                                         char filename[MAX_PATHLEN];
 217
 218                                                         /* pass devices with a "dev" file */
 219                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 220                                                                 snprintf(filename, MAX_PATHLEN, "/class/%s/%s",
 221                                                                          dent->d_name, dent2->d_name);
 222                                                                 filename[MAX_PATHLEN-1] = '\0';
 223                                                                 device_list_insert(filename, dent->d_name, &device_list);
 224                                                                 break;
 225                                                         }
 226                                                 }
 227                                                 closedir(dir3);
 228                                         }
 229                                 }
 230                                 closedir(dir2);
 231                         }
 232                 }
 233                 closedir(dir);
 234         }
 235
 236         exec_list(&device_list);
 237 }
 238
 239 int udev_start(void)
 240 {
 241         udev_scan_class();
 242         udev_scan_block();
 243         return 0;
 244 }