src/libudev/libudev-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <stddef.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "libudev.h"
  28
  29 #include "MurmurHash2.h"
  30 #include "device-nodes.h"
  31 #include "libudev-private.h"
  32 #include "utf8.h"
  33
  34 /**
  35  * SECTION:libudev-util
  36  * @short_description: utils
  37  *
  38  * Utilities useful when dealing with devices and device node names.
  39  */
  40
  41 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
  42 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
  43                                char *result, size_t maxsize, int read_value)
  44 {
  45         char temp[UTIL_PATH_SIZE];
  46         char *subsys;
  47         char *sysname;
  48         struct udev_device *dev;
  49         char *attr;
  50
  51         if (string[0] != '[')
  52                 return -1;
  53
  54         strscpy(temp, sizeof(temp), string);
  55
  56         subsys = &temp[1];
  57
  58         sysname = strchr(subsys, '/');
  59         if (sysname == NULL)
  60                 return -1;
  61         sysname[0] = '\0';
  62         sysname = &sysname[1];
  63
  64         attr = strchr(sysname, ']');
  65         if (attr == NULL)
  66                 return -1;
  67         attr[0] = '\0';
  68         attr = &attr[1];
  69         if (attr[0] == '/')
  70                 attr = &attr[1];
  71         if (attr[0] == '\0')
  72                 attr = NULL;
  73
  74         if (read_value && attr == NULL)
  75                 return -1;
  76
  77         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
  78         if (dev == NULL)
  79                 return -1;
  80
  81         if (read_value) {
  82                 const char *val;
  83
  84                 val = udev_device_get_sysattr_value(dev, attr);
  85                 if (val != NULL)
  86                         strscpy(result, maxsize, val);
  87                 else
  88                         result[0] = '\0';
  89                 log_debug("value '[%s/%s]%s' is '%s'", subsys, sysname, attr, result);
  90         } else {
  91                 size_t l;
  92                 char *s;
  93
  94                 s = result;
  95                 l = strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
  96                 if (attr != NULL)
  97                         strpcpyl(&s, l, "/", attr, NULL);
  98                 log_debug("path '[%s/%s]%s' is '%s'", subsys, sysname, attr, result);
  99         }
 100         udev_device_unref(dev);
 101         return 0;
 102 }
 103
 104 int util_log_priority(const char *priority)
 105 {
 106         char *endptr;
 107         int prio;
 108
 109         prio = strtoul(priority, &endptr, 10);
 110         if (endptr[0] == '\0' || isspace(endptr[0])) {
 111                 if (prio >= 0 && prio <= 7)
 112                         return prio;
 113                 else
 114                         return -ERANGE;
 115         }
 116
 117         return log_level_from_string(priority);
 118 }
 119
 120 size_t util_path_encode(const char *src, char *dest, size_t size)
 121 {
 122         size_t i, j;
 123
 124         for (i = 0, j = 0; src[i] != '\0'; i++) {
 125                 if (src[i] == '/') {
 126                         if (j+4 >= size) {
 127                                 j = 0;
 128                                 break;
 129                         }
 130                         memcpy(&dest[j], "\\x2f", 4);
 131                         j += 4;
 132                 } else if (src[i] == '\\') {
 133                         if (j+4 >= size) {
 134                                 j = 0;
 135                                 break;
 136                         }
 137                         memcpy(&dest[j], "\\x5c", 4);
 138                         j += 4;
 139                 } else {
 140                         if (j+1 >= size) {
 141                                 j = 0;
 142                                 break;
 143                         }
 144                         dest[j] = src[i];
 145                         j++;
 146                 }
 147         }
 148         dest[j] = '\0';
 149         return j;
 150 }
 151
 152 void util_remove_trailing_chars(char *path, char c)
 153 {
 154         size_t len;
 155
 156         if (path == NULL)
 157                 return;
 158         len = strlen(path);
 159         while (len > 0 && path[len-1] == c)
 160                 path[--len] = '\0';
 161 }
 162
 163 int util_replace_whitespace(const char *str, char *to, size_t len)
 164 {
 165         size_t i, j;
 166
 167         /* strip trailing whitespace */
 168         len = strnlen(str, len);
 169         while (len && isspace(str[len-1]))
 170                 len--;
 171
 172         /* strip leading whitespace */
 173         i = 0;
 174         while ((i < len) && isspace(str[i]))
 175                 i++;
 176
 177         j = 0;
 178         while (i < len) {
 179                 /* substitute multiple whitespace with a single '_' */
 180                 if (isspace(str[i])) {
 181                         while (isspace(str[i]))
 182                                 i++;
 183                         to[j++] = '_';
 184                 }
 185                 to[j++] = str[i++];
 186         }
 187         to[j] = '\0';
 188         return 0;
 189 }
 190
 191 /* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
 192 int util_replace_chars(char *str, const char *white)
 193 {
 194         size_t i = 0;
 195         int replaced = 0;
 196
 197         while (str[i] != '\0') {
 198                 int len;
 199
 200                 if (whitelisted_char_for_devnode(str[i], white)) {
 201                         i++;
 202                         continue;
 203                 }
 204
 205                 /* accept hex encoding */
 206                 if (str[i] == '\\' && str[i+1] == 'x') {
 207                         i += 2;
 208                         continue;
 209                 }
 210
 211                 /* accept valid utf8 */
 212                 len = utf8_encoded_valid_unichar(&str[i]);
 213                 if (len > 1) {
 214                         i += len;
 215                         continue;
 216                 }
 217
 218                 /* if space is allowed, replace whitespace with ordinary space */
 219                 if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
 220                         str[i] = ' ';
 221                         i++;
 222                         replaced++;
 223                         continue;
 224                 }
 225
 226                 /* everything else is replaced with '_' */
 227                 str[i] = '_';
 228                 i++;
 229                 replaced++;
 230         }
 231         return replaced;
 232 }
 233
 234 /**
 235  * udev_util_encode_string:
 236  * @str: input string to be encoded
 237  * @str_enc: output string to store the encoded input string
 238  * @len: maximum size of the output string, which may be
 239  *       four times as long as the input string
 240  *
 241  * Encode all potentially unsafe characters of a string to the
 242  * corresponding 2 char hex value prefixed by '\x'.
 243  *
 244  * Returns: 0 if the entire string was copied, non-zero otherwise.
 245  **/
 246 _public_ int udev_util_encode_string(const char *str, char *str_enc, size_t len)
 247 {
 248         return encode_devnode_name(str, str_enc, len);
 249 }
 250
 251 unsigned int util_string_hash32(const char *str)
 252 {
 253         return MurmurHash2(str, strlen(str), 0);
 254 }
 255
 256 /* get a bunch of bit numbers out of the hash, and set the bits in our bit field */
 257 uint64_t util_string_bloom64(const char *str)
 258 {
 259         uint64_t bits = 0;
 260         unsigned int hash = util_string_hash32(str);
 261
 262         bits |= 1LLU << (hash & 63);
 263         bits |= 1LLU << ((hash >> 6) & 63);
 264         bits |= 1LLU << ((hash >> 12) & 63);
 265         bits |= 1LLU << ((hash >> 18) & 63);
 266         return bits;
 267 }