libblkid-tiny/mkdev.c

   1 /*
   2  * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   3  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License version 2.1
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #define _BSD_SOURCE
  16
  17 #include <sys/stat.h>
  18 #include <sys/types.h>
  19
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <stdbool.h>
  25 #include <dirent.h>
  26 #include <limits.h>
  27 #include <fnmatch.h>
  28
  29 #include "libblkid-tiny.h"
  30
  31 #include <syslog.h>
  32
  33 static char buf[PATH_MAX];
  34 static char buf2[PATH_MAX];
  35 static unsigned int mode = 0600;
  36
  37 static void make_dev(const char *path, bool block, int major, int minor)
  38 {
  39         unsigned int _mode = mode | (block ? S_IFBLK : S_IFCHR);
  40
  41         mknod(path, _mode, makedev(major, minor));
  42 }
  43
  44 static void find_devs(bool block)
  45 {
  46         char *path = block ? "/sys/dev/block" : "/sys/dev/char";
  47         struct dirent *dp;
  48         DIR *dir;
  49
  50         dir = opendir(path);
  51         if (!dir)
  52                 return;
  53
  54         path = buf2 + sprintf(buf2, "%s/", path);
  55         while ((dp = readdir(dir)) != NULL) {
  56                 char *c;
  57                 int major = 0, minor = 0;
  58                 int len;
  59
  60                 if (dp->d_type != DT_LNK)
  61                         continue;
  62
  63                 if (sscanf(dp->d_name, "%d:%d", &major, &minor) != 2)
  64                         continue;
  65
  66                 strcpy(path, dp->d_name);
  67                 len = readlink(buf2, buf, sizeof(buf));
  68                 if (len <= 0)
  69                         continue;
  70
  71                 buf[len] = 0;
  72
  73                 c = strrchr(buf, '/');
  74                 if (!c)
  75                         continue;
  76
  77
  78                 c++;
  79                 make_dev(c, block, major, minor);
  80         }
  81         closedir(dir);
  82 }
  83
  84 int mkblkdev(void)
  85 {
  86         if (chdir("/dev"))
  87                 return 1;
  88
  89         mode = 0600;
  90         find_devs(true);
  91         chdir("/");
  92
  93         return 0;
  94 }