util-linux/mdev.c

   1 /* vi:set ts=4:
   2  *
   3  * mdev - Mini udev for busybox
   4  *
   5  * Copyright 2005 Rob Landley <rob@landley.net>
   6  * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  */
  10
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <fcntl.h>
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <sys/stat.h>
  17 #include <sys/types.h>
  18 #include <unistd.h>
  19
  20 #define DEV_PATH        "/dev"
  21 #define DEV_MODE        0660
  22
  23 #include <busybox.h>
  24
  25 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
  26 void make_device(char *path)
  27 {
  28         char *device_name, *s;
  29         int major,minor,type,len,fd;
  30
  31         RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
  32
  33         /* Try to read major/minor string */
  34
  35         snprintf(temp, PATH_MAX, "%s/dev", path);
  36         fd = open(temp, O_RDONLY);
  37         len = read(fd, temp, PATH_MAX-1);
  38         if (len<1) goto end;
  39         temp[len] = 0;
  40         close(fd);
  41
  42         /* Determine device name, type, major and minor */
  43
  44         device_name = strrchr(path, '/') + 1;
  45         type = strncmp(path+5, "block/" ,6) ? S_IFCHR : S_IFBLK;
  46         major = minor = 0;
  47         for(s = temp; *s; s++) {
  48                 if(*s == ':') {
  49                         major = minor;
  50                         minor = 0;
  51                 } else {
  52                         minor *= 10;
  53                         minor += (*s) - '0';
  54                 }
  55         }
  56
  57 /* Open config file here, look up permissions */
  58
  59         sprintf(temp, "%s/%s", DEV_PATH, device_name);
  60         if(mknod(temp, DEV_MODE | type, makedev(major, minor)) && errno != EEXIST)
  61                 bb_perror_msg_and_die("mknod %s failed", temp);
  62
  63 /* Perform shellout here */
  64
  65 end:
  66         RELEASE_CONFIG_BUFFER(temp);
  67 }
  68
  69 /* Recursive search of /sys/block or /sys/class.  path must be a writeable
  70  * buffer of size PATH_MAX containing the directory string to start at. */
  71
  72 void find_dev(char *path)
  73 {
  74         DIR *dir;
  75         int len=strlen(path);
  76
  77         if(!(dir = opendir(path)))
  78                 bb_perror_msg_and_die("No %s",path);
  79
  80         for(;;) {
  81                 struct dirent *entry = readdir(dir);
  82
  83                 if(!entry) break;
  84
  85                 /* Skip "." and ".." (also skips hidden files, which is ok) */
  86
  87                 if (entry->d_name[0]=='.') continue;
  88
  89                 if (entry->d_type == DT_DIR) {
  90                         snprintf(path+len, PATH_MAX-len, "/%s", entry->d_name);
  91                         find_dev(path);
  92                         path[len] = 0;
  93                 }
  94
  95                 /* If there's a dev entry, mknod it */
  96
  97                 if (strcmp(entry->d_name, "dev")) make_device(path);
  98         }
  99
 100         closedir(dir);
 101 }
 102
 103 int mdev_main(int argc, char *argv[])
 104 {
 105         if (argc > 1) {
 106                 if(argc == 2 && !strcmp(argv[1],"-s")) {
 107                         RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
 108                         strcpy(temp,"/sys/block");
 109                         find_dev(temp);
 110                         strcpy(temp,"/sys/class");
 111                         find_dev(temp);
 112                         if(ENABLE_FEATURE_CLEAN_UP)
 113                                 RELEASE_CONFIG_BUFFER(temp);
 114                         return 0;
 115                 } else bb_show_usage();
 116         }
 117
 118 /* hotplug support goes here */
 119
 120         return 0;
 121 }