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 _DEFAULT_SOURCE
  16
  17 #include <sys/stat.h>
  18 #include <sys/types.h>
  19 #include <sys/sysmacros.h>
  20
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include <stdbool.h>
  26 #include <dirent.h>
  27 #include <limits.h>
  28 #include <fnmatch.h>
  29
  30 #include "init.h"
  31
  32 static char **patterns;
  33 static int n_patterns;
  34 static char buf[PATH_MAX];
  35 static char buf2[PATH_MAX];
  36 static unsigned int mode = 0600;
  37
  38 static bool find_pattern(const char *name)
  39 {
  40         int i;
  41
  42         for (i = 0; i < n_patterns; i++)
  43                 if (!fnmatch(patterns[i], name, 0))
  44                         return true;
  45
  46         return false;
  47 }
  48
  49 static void make_dev(const char *path, bool block, int major, int minor)
  50 {
  51         unsigned int oldumask = umask(0);
  52         unsigned int _mode = mode | (block ? S_IFBLK : S_IFCHR);
  53
  54         DEBUG(4, "Creating %s device %s(%d,%d)\n",
  55                 block ? "block" : "character",
  56                 path, major, minor);
  57
  58         mknod(path, _mode, makedev(major, minor));
  59         umask(oldumask);
  60 }
  61
  62 static void find_devs(bool block)
  63 {
  64         char *path = block ? "/sys/dev/block" : "/sys/dev/char";
  65         struct dirent *dp;
  66         DIR *dir;
  67
  68         dir = opendir(path);
  69         if (!dir)
  70                 return;
  71
  72         path = buf2 + sprintf(buf2, "%s/", path);
  73         while ((dp = readdir(dir)) != NULL) {
  74                 char *c;
  75                 int major = 0, minor = 0;
  76                 int len;
  77
  78                 if (dp->d_type != DT_LNK)
  79                         continue;
  80
  81                 if (sscanf(dp->d_name, "%d:%d", &major, &minor) != 2)
  82                         continue;
  83
  84                 strcpy(path, dp->d_name);
  85                 len = readlink(buf2, buf, sizeof(buf));
  86                 if (len <= 0)
  87                         continue;
  88
  89                 buf[len] = 0;
  90                 if (!find_pattern(buf))
  91                         continue;
  92
  93                 c = strrchr(buf, '/');
  94                 if (!c)
  95                         continue;
  96
  97                 c++;
  98                 make_dev(c, block, major, minor);
  99         }
 100         closedir(dir);
 101 }
 102
 103 static char *add_pattern(const char *name)
 104 {
 105         char *str = malloc(strlen(name) + 2);
 106
 107         str[0] = '*';
 108         strcpy(str + 1, name);
 109         return str;
 110 }
 111
 112 int mkdev(const char *name, int _mode)
 113 {
 114         char *pattern;
 115
 116         if (chdir("/dev"))
 117                 return 1;
 118
 119         pattern = add_pattern(name);
 120         patterns = &pattern;
 121         mode = _mode;
 122         n_patterns = 1;
 123         find_devs(true);
 124         find_devs(false);
 125         free(pattern);
 126         return chdir("/");
 127 }