initd/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 "init.h"
  30
  31 #include "../log.h"
  32
  33 static char **patterns;
  34 static int n_patterns;
  35 static char buf[PATH_MAX];
  36 static char buf2[PATH_MAX];
  37 static unsigned int mode = 0600;
  38
  39 static bool find_pattern(const char *name)
  40 {
  41         int i;
  42
  43         for (i = 0; i < n_patterns; i++)
  44                 if (!fnmatch(patterns[i], name, 0))
  45                         return true;
  46
  47         return false;
  48 }
  49
  50 static void make_dev(const char *path, bool block, int major, int minor)
  51 {
  52         unsigned int oldumask = umask(0);
  53         unsigned int _mode = mode | (block ? S_IFBLK : S_IFCHR);
  54
  55         DEBUG(4, "Creating %s device %s(%d,%d)\n",
  56                 block ? "block" : "character",
  57                 path, major, minor);
  58
  59         mknod(path, _mode, makedev(major, minor));
  60         umask(oldumask);
  61 }
  62
  63 static void find_devs(bool block)
  64 {
  65         char *path = block ? "/sys/dev/block" : "/sys/dev/char";
  66         struct dirent *dp;
  67         DIR *dir;
  68
  69         dir = opendir(path);
  70         if (!dir)
  71                 return;
  72
  73         path = buf2 + sprintf(buf2, "%s/", path);
  74         while ((dp = readdir(dir)) != NULL) {
  75                 char *c;
  76                 int major = 0, minor = 0;
  77                 int len;
  78
  79                 if (dp->d_type != DT_LNK)
  80                         continue;
  81
  82                 if (sscanf(dp->d_name, "%d:%d", &major, &minor) != 2)
  83                         continue;
  84
  85                 strcpy(path, dp->d_name);
  86                 len = readlink(buf2, buf, sizeof(buf));
  87                 if (len <= 0)
  88                         continue;
  89
  90                 buf[len] = 0;
  91                 if (!find_pattern(buf))
  92                         continue;
  93
  94                 c = strrchr(buf, '/');
  95                 if (!c)
  96                         continue;
  97
  98                 c++;
  99                 make_dev(c, block, major, minor);
 100         }
 101         closedir(dir);
 102 }
 103
 104 static char *add_pattern(const char *name)
 105 {
 106         char *str = malloc(strlen(name) + 2);
 107
 108         str[0] = '*';
 109         strcpy(str + 1, name);
 110         return str;
 111 }
 112
 113 int mkdev(const char *name, int _mode)
 114 {
 115         char *pattern;
 116
 117         if (chdir("/dev"))
 118                 return 1;
 119
 120         pattern = add_pattern(name);
 121         patterns = &pattern;
 122         mode = _mode;
 123         n_patterns = 1;
 124         find_devs(true);
 125         find_devs(false);
 126         chdir("/");
 127
 128         return 0;
 129 }