src/libudev/libudev-util.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008-2011 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <stddef.h>
  15 #include <unistd.h>
  16 #include <errno.h>
  17 #include <string.h>
  18 #include <dirent.h>
  19 #include <ctype.h>
  20 #include <fcntl.h>
  21 #include <time.h>
  22 #include <pwd.h>
  23 #include <grp.h>
  24 #include <sys/stat.h>
  25 #include <sys/param.h>
  26
  27 #include "libudev.h"
  28 #include "libudev-private.h"
  29
  30 /**
  31  * SECTION:libudev-util
  32  * @short_description: utils
  33  *
  34  * Utilities useful when dealing with devices and device node names.
  35  */
  36
  37 int util_delete_path(struct udev *udev, const char *path)
  38 {
  39         char p[UTIL_PATH_SIZE];
  40         char *pos;
  41         int err = 0;
  42
  43         if (path[0] == '/')
  44                 while(path[1] == '/')
  45                         path++;
  46         util_strscpy(p, sizeof(p), path);
  47         pos = strrchr(p, '/');
  48         if (pos == p || pos == NULL)
  49                 return 0;
  50
  51         for (;;) {
  52                 *pos = '\0';
  53                 pos = strrchr(p, '/');
  54
  55                 /* don't remove the last one */
  56                 if ((pos == p) || (pos == NULL))
  57                         break;
  58
  59                 err = rmdir(p);
  60                 if (err < 0) {
  61                         if (errno == ENOENT)
  62                                 err = 0;
  63                         break;
  64                 }
  65         }
  66         return err;
  67 }
  68
  69 uid_t util_lookup_user(struct udev *udev, const char *user)
  70 {
  71         char *endptr;
  72         struct passwd pwbuf;
  73         struct passwd *pw;
  74         uid_t uid;
  75         size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
  76         char *buf = alloca(buflen);
  77
  78         if (strcmp(user, "root") == 0)
  79                 return 0;
  80         uid = strtoul(user, &endptr, 10);
  81         if (endptr[0] == '\0')
  82                 return uid;
  83
  84         errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
  85         if (pw != NULL)
  86                 return pw->pw_uid;
  87         if (errno == 0 || errno == ENOENT || errno == ESRCH)
  88                 err(udev, "specified user '%s' unknown\n", user);
  89         else
  90                 err(udev, "error resolving user '%s': %m\n", user);
  91         return 0;
  92 }
  93
  94 gid_t util_lookup_group(struct udev *udev, const char *group)
  95 {
  96         char *endptr;
  97         struct group grbuf;
  98         struct group *gr;
  99         gid_t gid = 0;
 100         size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 101         char *buf = NULL;
 102
 103         if (strcmp(group, "root") == 0)
 104                 return 0;
 105         gid = strtoul(group, &endptr, 10);
 106         if (endptr[0] == '\0')
 107                 return gid;
 108         gid = 0;
 109         for (;;) {
 110                 char *newbuf;
 111
 112                 newbuf = realloc(buf, buflen);
 113                 if (!newbuf)
 114                         break;
 115                 buf = newbuf;
 116                 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
 117                 if (gr != NULL) {
 118                         gid = gr->gr_gid;
 119                 } else if (errno == ERANGE) {
 120                         buflen *= 2;
 121                         continue;
 122                 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
 123                         err(udev, "specified group '%s' unknown\n", group);
 124                 } else {
 125                         err(udev, "error resolving group '%s': %m\n", group);
 126                 }
 127                 break;
 128         }
 129         free(buf);
 130         return gid;
 131 }
 132
 133 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
 134 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 135                                char *result, size_t maxsize, int read_value)
 136 {
 137         char temp[UTIL_PATH_SIZE];
 138         char *subsys;
 139         char *sysname;
 140         struct udev_device *dev;
 141         char *attr;
 142
 143         if (string[0] != '[')
 144                 return -1;
 145
 146         util_strscpy(temp, sizeof(temp), string);
 147
 148         subsys = &temp[1];
 149
 150         sysname = strchr(subsys, '/');
 151         if (sysname == NULL)
 152                 return -1;
 153         sysname[0] = '\0';
 154         sysname = &sysname[1];
 155
 156         attr = strchr(sysname, ']');
 157         if (attr == NULL)
 158                 return -1;
 159         attr[0] = '\0';
 160         attr = &attr[1];
 161         if (attr[0] == '/')
 162                 attr = &attr[1];
 163         if (attr[0] == '\0')
 164                 attr = NULL;
 165
 166         if (read_value && attr == NULL)
 167                 return -1;
 168
 169         dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 170         if (dev == NULL)
 171                 return -1;
 172
 173         if (read_value) {
 174                 const char *val;
 175
 176                 val = udev_device_get_sysattr_value(dev, attr);
 177                 if (val != NULL)
 178                         util_strscpy(result, maxsize, val);
 179                 else
 180                         result[0] = '\0';
 181                 dbg(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 182         } else {
 183                 size_t l;
 184                 char *s;
 185
 186                 s = result;
 187                 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
 188                 if (attr != NULL)
 189                         util_strpcpyl(&s, l, "/", attr, NULL);
 190                 dbg(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
 191         }
 192         udev_device_unref(dev);
 193         return 0;
 194 }
 195 ssize_t util_get_sys_core_link_value(struct udev *udev, const char *slink, const char *syspath, char *value, size_t size)
 196 {
 197         char path[UTIL_PATH_SIZE];
 198         char target[UTIL_PATH_SIZE];
 199         ssize_t len;
 200         const char *pos;
 201
 202         util_strscpyl(path, sizeof(path), syspath, "/", slink, NULL);
 203         len = readlink(path, target, sizeof(target));
 204         if (len <= 0 || len == (ssize_t)sizeof(target))
 205                 return -1;
 206         target[len] = '\0';
 207         pos = strrchr(target, '/');
 208         if (pos == NULL)
 209                 return -1;
 210         pos = &pos[1];
 211         return util_strscpy(value, size, pos);
 212 }
 213
 214 int util_resolve_sys_link(struct udev *udev, char *syspath, size_t size)
 215 {
 216         char link_target[UTIL_PATH_SIZE];
 217
 218         ssize_t len;
 219         int i;
 220         int back;
 221         char *base = NULL;
 222
 223         len = readlink(syspath, link_target, sizeof(link_target));
 224         if (len <= 0 || len == (ssize_t)sizeof(link_target))
 225                 return -1;
 226         link_target[len] = '\0';
 227
 228         for (back = 0; startswith(&link_target[back * 3], "../"); back++)
 229                 ;
 230         for (i = 0; i <= back; i++) {
 231                 base = strrchr(syspath, '/');
 232                 if (base == NULL)
 233                         return -EINVAL;
 234                 base[0] = '\0';
 235         }
 236         if (base == NULL)
 237                 return -EINVAL;
 238         util_strscpyl(base, size - (base - syspath), "/", &link_target[back * 3], NULL);
 239         return 0;
 240 }
 241
 242 int util_log_priority(const char *priority)
 243 {
 244         char *endptr;
 245         int prio;
 246
 247         prio = strtol(priority, &endptr, 10);
 248         if (endptr[0] == '\0' || isspace(endptr[0]))
 249                 return prio;
 250         if (startswith(priority, "err"))
 251                 return LOG_ERR;
 252         if (startswith(priority, "info"))
 253                 return LOG_INFO;
 254         if (startswith(priority, "debug"))
 255                 return LOG_DEBUG;
 256         return 0;
 257 }
 258
 259 size_t util_path_encode(const char *src, char *dest, size_t size)
 260 {
 261         size_t i, j;
 262
 263         for (i = 0, j = 0; src[i] != '\0'; i++) {
 264                 if (src[i] == '/') {
 265                         if (j+4 >= size) {
 266                                 j = 0;
 267                                 break;
 268                         }
 269                         memcpy(&dest[j], "\\x2f", 4);
 270                         j += 4;
 271                 } else if (src[i] == '\\') {
 272                         if (j+4 >= size) {
 273                                 j = 0;
 274                                 break;
 275                         }
 276                         memcpy(&dest[j], "\\x5c", 4);
 277                         j += 4;
 278                 } else {
 279                         if (j+1 >= size) {
 280                                 j = 0;
 281                                 break;
 282                         }
 283                         dest[j] = src[i];
 284                         j++;
 285                 }
 286         }
 287         dest[j] = '\0';
 288         return j;
 289 }
 290
 291 size_t util_path_decode(char *s)
 292 {
 293         size_t i, j;
 294
 295         for (i = 0, j = 0; s[i] != '\0'; j++) {
 296                 if (memcmp(&s[i], "\\x2f", 4) == 0) {
 297                         s[j] = '/';
 298                         i += 4;
 299                 } else if (memcmp(&s[i], "\\x5c", 4) == 0) {
 300                         s[j] = '\\';
 301                         i += 4;
 302                 } else {
 303                         s[j] = s[i];
 304                         i++;
 305                 }
 306         }
 307         s[j] = '\0';
 308         return j;
 309 }
 310
 311 void util_remove_trailing_chars(char *path, char c)
 312 {
 313         size_t len;
 314
 315         if (path == NULL)
 316                 return;
 317         len = strlen(path);
 318         while (len > 0 && path[len-1] == c)
 319                 path[--len] = '\0';
 320 }
 321
 322 /*
 323  * Concatenates strings. In any case, terminates in _all_ cases with '\0'
 324  * and moves the @dest pointer forward to the added '\0'. Returns the
 325  * remaining size, and 0 if the string was truncated.
 326  */
 327 size_t util_strpcpy(char **dest, size_t size, const char *src)
 328 {
 329         size_t len;
 330
 331         len = strlen(src);
 332         if (len >= size) {
 333                 if (size > 1)
 334                         *dest = mempcpy(*dest, src, size-1);
 335                 size = 0;
 336                 *dest[0] = '\0';
 337         } else {
 338                 if (len > 0) {
 339                         *dest = mempcpy(*dest, src, len);
 340                         size -= len;
 341                 }
 342                 *dest[0] = '\0';
 343         }
 344         return size;
 345 }
 346
 347 /* concatenates list of strings, moves dest forward */
 348 size_t util_strpcpyl(char **dest, size_t size, const char *src, ...)
 349 {
 350         va_list va;
 351
 352         va_start(va, src);
 353         do {
 354                 size = util_strpcpy(dest, size, src);
 355                 src = va_arg(va, char *);
 356         } while (src != NULL);
 357         va_end(va);
 358
 359         return size;
 360 }
 361
 362 /* copies string */
 363 size_t util_strscpy(char *dest, size_t size, const char *src)
 364 {
 365         char *s;
 366
 367         s = dest;
 368         return util_strpcpy(&s, size, src);
 369 }
 370
 371 /* concatenates list of strings */
 372 size_t util_strscpyl(char *dest, size_t size, const char *src, ...)
 373 {
 374         va_list va;
 375         char *s;
 376
 377         va_start(va, src);
 378         s = dest;
 379         do {
 380                 size = util_strpcpy(&s, size, src);
 381                 src = va_arg(va, char *);
 382         } while (src != NULL);
 383         va_end(va);
 384
 385         return size;
 386 }
 387
 388 /* count of characters used to encode one unicode char */
 389 static int utf8_encoded_expected_len(const char *str)
 390 {
 391         unsigned char c = (unsigned char)str[0];
 392
 393         if (c < 0x80)
 394                 return 1;
 395         if ((c & 0xe0) == 0xc0)
 396                 return 2;
 397         if ((c & 0xf0) == 0xe0)
 398                 return 3;
 399         if ((c & 0xf8) == 0xf0)
 400                 return 4;
 401         if ((c & 0xfc) == 0xf8)
 402                 return 5;
 403         if ((c & 0xfe) == 0xfc)
 404                 return 6;
 405         return 0;
 406 }
 407
 408 /* decode one unicode char */
 409 static int utf8_encoded_to_unichar(const char *str)
 410 {
 411         int unichar;
 412         int len;
 413         int i;
 414
 415         len = utf8_encoded_expected_len(str);
 416         switch (len) {
 417         case 1:
 418                 return (int)str[0];
 419         case 2:
 420                 unichar = str[0] & 0x1f;
 421                 break;
 422         case 3:
 423                 unichar = (int)str[0] & 0x0f;
 424                 break;
 425         case 4:
 426                 unichar = (int)str[0] & 0x07;
 427                 break;
 428         case 5:
 429                 unichar = (int)str[0] & 0x03;
 430                 break;
 431         case 6:
 432                 unichar = (int)str[0] & 0x01;
 433                 break;
 434         default:
 435                 return -1;
 436         }
 437
 438         for (i = 1; i < len; i++) {
 439                 if (((int)str[i] & 0xc0) != 0x80)
 440                         return -1;
 441                 unichar <<= 6;
 442                 unichar |= (int)str[i] & 0x3f;
 443         }
 444
 445         return unichar;
 446 }
 447
 448 /* expected size used to encode one unicode char */
 449 static int utf8_unichar_to_encoded_len(int unichar)
 450 {
 451         if (unichar < 0x80)
 452                 return 1;
 453         if (unichar < 0x800)
 454                 return 2;
 455         if (unichar < 0x10000)
 456                 return 3;
 457         if (unichar < 0x200000)
 458                 return 4;
 459         if (unichar < 0x4000000)
 460                 return 5;
 461         return 6;
 462 }
 463
 464 /* check if unicode char has a valid numeric range */
 465 static int utf8_unichar_valid_range(int unichar)
 466 {
 467         if (unichar > 0x10ffff)
 468                 return 0;
 469         if ((unichar & 0xfffff800) == 0xd800)
 470                 return 0;
 471         if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
 472                 return 0;
 473         if ((unichar & 0xffff) == 0xffff)
 474                 return 0;
 475         return 1;
 476 }
 477
 478 /* validate one encoded unicode char and return its length */
 479 static int utf8_encoded_valid_unichar(const char *str)
 480 {
 481         int len;
 482         int unichar;
 483         int i;
 484
 485         len = utf8_encoded_expected_len(str);
 486         if (len == 0)
 487                 return -1;
 488
 489         /* ascii is valid */
 490         if (len == 1)
 491                 return 1;
 492
 493         /* check if expected encoded chars are available */
 494         for (i = 0; i < len; i++)
 495                 if ((str[i] & 0x80) != 0x80)
 496                         return -1;
 497
 498         unichar = utf8_encoded_to_unichar(str);
 499
 500         /* check if encoded length matches encoded value */
 501         if (utf8_unichar_to_encoded_len(unichar) != len)
 502                 return -1;
 503
 504         /* check if value has valid range */
 505         if (!utf8_unichar_valid_range(unichar))
 506                 return -1;
 507
 508         return len;
 509 }
 510
 511 int util_replace_whitespace(const char *str, char *to, size_t len)
 512 {
 513         size_t i, j;
 514
 515         /* strip trailing whitespace */
 516         len = strnlen(str, len);
 517         while (len && isspace(str[len-1]))
 518                 len--;
 519
 520         /* strip leading whitespace */
 521         i = 0;
 522         while (isspace(str[i]) && (i < len))
 523                 i++;
 524
 525         j = 0;
 526         while (i < len) {
 527                 /* substitute multiple whitespace with a single '_' */
 528                 if (isspace(str[i])) {
 529                         while (isspace(str[i]))
 530                                 i++;
 531                         to[j++] = '_';
 532                 }
 533                 to[j++] = str[i++];
 534         }
 535         to[j] = '\0';
 536         return 0;
 537 }
 538
 539 static int is_whitelisted(char c, const char *white)
 540 {
 541         if ((c >= '0' && c <= '9') ||
 542             (c >= 'A' && c <= 'Z') ||
 543             (c >= 'a' && c <= 'z') ||
 544             strchr("#+-.:=@_", c) != NULL ||
 545             (white != NULL && strchr(white, c) != NULL))
 546                 return 1;
 547         return 0;
 548 }
 549
 550 /* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
 551 int util_replace_chars(char *str, const char *white)
 552 {
 553         size_t i = 0;
 554         int replaced = 0;
 555
 556         while (str[i] != '\0') {
 557                 int len;
 558
 559                 if (is_whitelisted(str[i], white)) {
 560                         i++;
 561                         continue;
 562                 }
 563
 564                 /* accept hex encoding */
 565                 if (str[i] == '\\' && str[i+1] == 'x') {
 566                         i += 2;
 567                         continue;
 568                 }
 569
 570                 /* accept valid utf8 */
 571                 len = utf8_encoded_valid_unichar(&str[i]);
 572                 if (len > 1) {
 573                         i += len;
 574                         continue;
 575                 }
 576
 577                 /* if space is allowed, replace whitespace with ordinary space */
 578                 if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
 579                         str[i] = ' ';
 580                         i++;
 581                         replaced++;
 582                         continue;
 583                 }
 584
 585                 /* everything else is replaced with '_' */
 586                 str[i] = '_';
 587                 i++;
 588                 replaced++;
 589         }
 590         return replaced;
 591 }
 592
 593 /**
 594  * udev_util_encode_string:
 595  * @str: input string to be encoded
 596  * @str_enc: output string to store the encoded input string
 597  * @len: maximum size of the output string, which may be
 598  *       four times as long as the input string
 599  *
 600  * Encode all potentially unsafe characters of a string to the
 601  * corresponding 2 char hex value prefixed by '\x'.
 602  *
 603  * Returns: 0 if the entire string was copied, non-zero otherwise.
 604  **/
 605 _public_ int udev_util_encode_string(const char *str, char *str_enc, size_t len)
 606 {
 607         size_t i, j;
 608
 609         if (str == NULL || str_enc == NULL)
 610                 return -1;
 611
 612         for (i = 0, j = 0; str[i] != '\0'; i++) {
 613                 int seqlen;
 614
 615                 seqlen = utf8_encoded_valid_unichar(&str[i]);
 616                 if (seqlen > 1) {
 617                         if (len-j < (size_t)seqlen)
 618                                 goto err;
 619                         memcpy(&str_enc[j], &str[i], seqlen);
 620                         j += seqlen;
 621                         i += (seqlen-1);
 622                 } else if (str[i] == '\\' || !is_whitelisted(str[i], NULL)) {
 623                         if (len-j < 4)
 624                                 goto err;
 625                         sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
 626                         j += 4;
 627                 } else {
 628                         if (len-j < 1)
 629                                 goto err;
 630                         str_enc[j] = str[i];
 631                         j++;
 632                 }
 633         }
 634         if (len-j < 1)
 635                 goto err;
 636         str_enc[j] = '\0';
 637         return 0;
 638 err:
 639         return -1;
 640 }
 641
 642 /*
 643  * http://sites.google.com/site/murmurhash/
 644  *
 645  * All code is released to the public domain. For business purposes,
 646  * Murmurhash is under the MIT license.
 647  *
 648  */
 649 static unsigned int murmur_hash2(const char *key, int len, unsigned int seed)
 650 {
 651         /*
 652          *  'm' and 'r' are mixing constants generated offline.
 653          *  They're not really 'magic', they just happen to work well.
 654          */
 655         const unsigned int m = 0x5bd1e995;
 656         const int r = 24;
 657
 658         /* initialize the hash to a 'random' value */
 659         unsigned int h = seed ^ len;
 660
 661         /* mix 4 bytes at a time into the hash */
 662         const unsigned char * data = (const unsigned char *)key;
 663
 664         while(len >= 4) {
 665                 unsigned int k = *(unsigned int *)data;
 666
 667                 k *= m;
 668                 k ^= k >> r;
 669                 k *= m;
 670                 h *= m;
 671                 h ^= k;
 672
 673                 data += 4;
 674                 len -= 4;
 675         }
 676
 677         /* handle the last few bytes of the input array */
 678         switch(len) {
 679         case 3:
 680                 h ^= data[2] << 16;
 681         case 2:
 682                 h ^= data[1] << 8;
 683         case 1:
 684                 h ^= data[0];
 685                 h *= m;
 686         };
 687
 688         /* do a few final mixes of the hash to ensure the last few bytes are well-incorporated */
 689         h ^= h >> 13;
 690         h *= m;
 691         h ^= h >> 15;
 692
 693         return h;
 694 }
 695
 696 unsigned int util_string_hash32(const char *str)
 697 {
 698         return murmur_hash2(str, strlen(str), 0);
 699 }
 700
 701 /* get a bunch of bit numbers out of the hash, and set the bits in our bit field */
 702 uint64_t util_string_bloom64(const char *str)
 703 {
 704         uint64_t bits = 0;
 705         unsigned int hash = util_string_hash32(str);
 706
 707         bits |= 1LLU << (hash & 63);
 708         bits |= 1LLU << ((hash >> 6) & 63);
 709         bits |= 1LLU << ((hash >> 12) & 63);
 710         bits |= 1LLU << ((hash >> 18) & 63);
 711         return bits;
 712 }
 713
 714 #define USEC_PER_SEC  1000000ULL
 715 #define NSEC_PER_USEC 1000ULL
 716 unsigned long long ts_usec(const struct timespec *ts)
 717 {
 718         return (unsigned long long) ts->tv_sec * USEC_PER_SEC +
 719                (unsigned long long) ts->tv_nsec / NSEC_PER_USEC;
 720 }
 721
 722 unsigned long long now_usec(void)
 723 {
 724         struct timespec ts;
 725
 726         if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
 727                 return 0;
 728         return ts_usec(&ts);
 729 }