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