src/shared/device-nodes.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <sys/stat.h>
   6
   7 #include "device-nodes.h"
   8 #include "path-util.h"
   9 #include "string-util.h"
  10 #include "utf8.h"
  11
  12 int allow_listed_char_for_devnode(char c, const char *additional) {
  13         return
  14                 ascii_isdigit(c) ||
  15                 ascii_isalpha(c) ||
  16                 strchr("#+-.:=@_", c) ||
  17                 (additional && strchr(additional, c));
  18 }
  19
  20 int encode_devnode_name(const char *str, char *str_enc, size_t len) {
  21         size_t i, j;
  22
  23         if (!str || !str_enc)
  24                 return -EINVAL;
  25
  26         for (i = 0, j = 0; str[i] != '\0'; i++) {
  27                 int seqlen;
  28
  29                 seqlen = utf8_encoded_valid_unichar(str + i, SIZE_MAX);
  30                 if (seqlen > 1) {
  31
  32                         if (len-j < (size_t) seqlen)
  33                                 return -EINVAL;
  34
  35                         memcpy(&str_enc[j], &str[i], seqlen);
  36                         j += seqlen;
  37                         i += (seqlen-1);
  38
  39                 } else if (str[i] == '\\' || !allow_listed_char_for_devnode(str[i], NULL)) {
  40
  41                         if (len-j < 4)
  42                                 return -EINVAL;
  43
  44                         sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
  45                         j += 4;
  46
  47                 } else {
  48                         if (len-j < 1)
  49                                 return -EINVAL;
  50
  51                         str_enc[j] = str[i];
  52                         j++;
  53                 }
  54         }
  55
  56         if (len-j < 1)
  57                 return -EINVAL;
  58
  59         str_enc[j] = '\0';
  60         return 0;
  61 }
  62
  63 int devnode_same(const char *a, const char *b) {
  64         struct stat sa, sb;
  65
  66         assert(a);
  67         assert(b);
  68
  69         if (!valid_device_node_path(a) || !valid_device_node_path(b))
  70                 return -EINVAL;
  71
  72         if (stat(a, &sa) < 0)
  73                 return -errno;
  74         if (stat(b, &sb) < 0)
  75                 return -errno;
  76
  77         if (!S_ISBLK(sa.st_mode) && !S_ISCHR(sa.st_mode))
  78                 return -ENODEV;
  79         if (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode))
  80                 return -ENODEV;
  81
  82         if (((sa.st_mode ^ sb.st_mode) & S_IFMT) != 0) /* both inode same device node type? */
  83                 return false;
  84
  85         return sa.st_rdev == sb.st_rdev;
  86 }