udev_rules_parse.c

   1 /*
   2  * udev_rules_parse.c
   3  *
   4  * Copyright (C) 2003,2004 Greg Kroah-Hartman <greg@kroah.com>
   5  * Copyright (C) 2003-2005 Kay Sievers <kay.sievers@vrfy.org>
   6  *
   7  *      This program is free software; you can redistribute it and/or modify it
   8  *      under the terms of the GNU General Public License as published by the
   9  *      Free Software Foundation version 2 of the License.
  10  *
  11  *      This program 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  *      General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU General Public License along
  17  *      with this program; if not, write to the Free Software Foundation, Inc.,
  18  *      675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #include <stddef.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26 #include <ctype.h>
  27 #include <unistd.h>
  28 #include <sys/stat.h>
  29 #include <errno.h>
  30
  31 #include "udev.h"
  32 #include "udev_rules.h"
  33
  34
  35 void udev_rules_iter_init(struct udev_rules *rules)
  36 {
  37         dbg("bufsize=%zi", rules->bufsize);
  38         rules->current = 0;
  39 }
  40
  41 struct udev_rule *udev_rules_iter_next(struct udev_rules *rules)
  42 {
  43         static struct udev_rule *rule;
  44
  45         if (!rules)
  46                 return NULL;
  47
  48         dbg("current=%zi", rules->current);
  49         if (rules->current >= rules->bufsize) {
  50                 dbg("no more rules");
  51                 return NULL;
  52         }
  53
  54         /* get next rule */
  55         rule = (struct udev_rule *) (rules->buf + rules->current);
  56         rules->current += sizeof(struct udev_rule) + rule->bufsize;
  57
  58         return rule;
  59 }
  60
  61 struct udev_rule *udev_rules_iter_label(struct udev_rules *rules, const char *label)
  62 {
  63         static struct udev_rule *rule;
  64
  65 next:
  66         dbg("current=%zi", rules->current);
  67         if (rules->current >= rules->bufsize) {
  68                 dbg("no more rules");
  69                 return NULL;
  70         }
  71         rule = (struct udev_rule *) (rules->buf + rules->current);
  72
  73         if (strcmp(&rule->buf[rule->label.val_off], label) != 0) {
  74                 dbg("moving forward, looking for label '%s'", label);
  75                 rules->current += sizeof(struct udev_rule) + rule->bufsize;
  76                 goto next;
  77         }
  78
  79         dbg("found label '%s'", label);
  80         return rule;
  81 }
  82
  83 static int get_key(char **line, char **key, enum key_operation *operation, char **value)
  84 {
  85         char *linepos;
  86         char *temp;
  87
  88         linepos = *line;
  89         if (linepos == NULL && linepos[0] == '\0')
  90                 return -1;
  91
  92         /* skip whitespace */
  93         while (isspace(linepos[0]) || linepos[0] == ',')
  94                 linepos++;
  95
  96         /* get the key */
  97         if (linepos[0] == '\0')
  98                 return -1;
  99         *key = linepos;
 100
 101         while (1) {
 102                 linepos++;
 103                 if (linepos[0] == '\0')
 104                         return -1;
 105                 if (isspace(linepos[0]))
 106                         break;
 107                 if (linepos[0] == '=')
 108                         break;
 109                 if (linepos[0] == '+')
 110                         break;
 111                 if (linepos[0] == '!')
 112                         break;
 113                 if (linepos[0] == ':')
 114                         break;
 115         }
 116
 117         /* remember end of key */
 118         temp = linepos;
 119
 120         /* skip whitespace after key */
 121         while (isspace(linepos[0]))
 122                 linepos++;
 123         if (linepos[0] == '\0')
 124                 return -1;
 125
 126         /* get operation type */
 127         if (linepos[0] == '=' && linepos[1] == '=') {
 128                 *operation = KEY_OP_MATCH;
 129                 linepos += 2;
 130                 dbg("operator=match");
 131         } else if (linepos[0] == '!' && linepos[1] == '=') {
 132                 *operation = KEY_OP_NOMATCH;
 133                 linepos += 2;
 134                 dbg("operator=nomatch");
 135         } else if (linepos[0] == '+' && linepos[1] == '=') {
 136                 *operation = KEY_OP_ADD;
 137                 linepos += 2;
 138                 dbg("operator=add");
 139         } else if (linepos[0] == '=') {
 140                 *operation = KEY_OP_ASSIGN;
 141                 linepos++;
 142                 dbg("operator=assign");
 143         } else if (linepos[0] == ':' && linepos[1] == '=') {
 144                 *operation = KEY_OP_ASSIGN_FINAL;
 145                 linepos += 2;
 146                 dbg("operator=assign_final");
 147         } else
 148                 return -1;
 149
 150         /* terminate key */
 151         temp[0] = '\0';
 152         dbg("key='%s'", *key);
 153
 154         /* skip whitespace after operator */
 155         while (isspace(linepos[0]))
 156                 linepos++;
 157         if (linepos[0] == '\0')
 158                 return -1;
 159
 160         /* get the value*/
 161         if (linepos[0] == '"')
 162                 linepos++;
 163         else
 164                 return -1;
 165         *value = linepos;
 166
 167         temp = strchr(linepos, '"');
 168         if (!temp)
 169                 return -1;
 170         temp[0] = '\0';
 171         temp++;
 172         dbg("value='%s'", *value);
 173
 174         /* move line to next key */
 175         *line = temp;
 176
 177         return 0;
 178 }
 179
 180 /* extract possible KEY{attr} */
 181 static char *get_key_attribute(char *str)
 182 {
 183         char *pos;
 184         char *attr;
 185
 186         attr = strchr(str, '{');
 187         if (attr != NULL) {
 188                 attr++;
 189                 pos = strchr(attr, '}');
 190                 if (pos == NULL) {
 191                         err("missing closing brace for format");
 192                         return NULL;
 193                 }
 194                 pos[0] = '\0';
 195                 dbg("attribute='%s'", attr);
 196                 return attr;
 197         }
 198
 199         return NULL;
 200 }
 201
 202 static int add_rule_key(struct udev_rule *rule, struct key *key,
 203                         enum key_operation operation, const char *value)
 204 {
 205         size_t val_len = strnlen(value, PATH_SIZE);
 206
 207         key->operation = operation;
 208
 209         key->val_off = rule->bufsize;
 210         strlcpy(rule->buf + rule->bufsize, value, val_len+1);
 211         rule->bufsize += val_len+1;
 212
 213         return 0;
 214 }
 215
 216 static int add_rule_key_pair(struct udev_rule *rule, struct key_pairs *pairs,
 217                              enum key_operation operation, const char *key, const char *value)
 218 {
 219         size_t key_len = strnlen(key, PATH_SIZE);
 220
 221         if (pairs->count >= PAIRS_MAX) {
 222                 err("skip, too many keys in a single rule");
 223                 return -1;
 224         }
 225
 226         add_rule_key(rule, &pairs->keys[pairs->count].key, operation, value);
 227
 228         /* add the key-name of the pair */
 229         pairs->keys[pairs->count].key_name_off = rule->bufsize;
 230         strlcpy(rule->buf + rule->bufsize, key, key_len+1);
 231         rule->bufsize += key_len+1;
 232
 233         pairs->count++;
 234
 235         return 0;
 236 }
 237
 238 static int add_to_rules(struct udev_rules *rules, char *line)
 239 {
 240         struct udev_rule *rule;
 241         size_t rule_size;
 242         int valid;
 243         char *linepos;
 244         char *attr;
 245         size_t padding;
 246         int retval;
 247
 248         /* get all the keys */
 249         rule = calloc(1, sizeof (struct udev_rule) + LINE_SIZE);
 250         if (!rule) {
 251                 err("malloc failed");
 252                 return -1;
 253         }
 254         linepos = line;
 255         valid = 0;
 256
 257         while (1) {
 258                 char *key;
 259                 char *value;
 260                 enum key_operation operation = KEY_OP_UNSET;
 261
 262                 retval = get_key(&linepos, &key, &operation, &value);
 263                 if (retval)
 264                         break;
 265
 266                 if (strcasecmp(key, "LABEL") == 0) {
 267                         add_rule_key(rule, &rule->label, operation, value);
 268                         valid = 1;
 269                         continue;
 270                 }
 271
 272                 if (strcasecmp(key, "GOTO") == 0) {
 273                         add_rule_key(rule, &rule->goto_label, operation, value);
 274                         valid = 1;
 275                         continue;
 276                 }
 277
 278                 if (strcasecmp(key, "KERNEL") == 0) {
 279                         add_rule_key(rule, &rule->kernel_name, operation, value);
 280                         valid = 1;
 281                         continue;
 282                 }
 283
 284                 if (strcasecmp(key, "SUBSYSTEM") == 0) {
 285                         add_rule_key(rule, &rule->subsystem, operation, value);
 286                         valid = 1;
 287                         continue;
 288                 }
 289
 290                 if (strcasecmp(key, "ACTION") == 0) {
 291                         add_rule_key(rule, &rule->action, operation, value);
 292                         valid = 1;
 293                         continue;
 294                 }
 295
 296                 if (strcasecmp(key, "DEVPATH") == 0) {
 297                         add_rule_key(rule, &rule->devpath, operation, value);
 298                         valid = 1;
 299                         continue;
 300                 }
 301
 302                 if (strcasecmp(key, "BUS") == 0) {
 303                         add_rule_key(rule, &rule->bus, operation, value);
 304                         valid = 1;
 305                         continue;
 306                 }
 307
 308                 if (strcasecmp(key, "ID") == 0) {
 309                         add_rule_key(rule, &rule->id, operation, value);
 310                         valid = 1;
 311                         continue;
 312                 }
 313
 314                 if (strncasecmp(key, "SYSFS", sizeof("SYSFS")-1) == 0) {
 315                         attr = get_key_attribute(key + sizeof("SYSFS")-1);
 316                         if (attr == NULL) {
 317                                 err("error parsing SYSFS attribute in '%s'", line);
 318                                 continue;
 319                         }
 320                         add_rule_key_pair(rule, &rule->sysfs, operation, attr, value);
 321                         valid = 1;
 322                         continue;
 323                 }
 324
 325                 if (strcasecmp(key, "WAIT_FOR_SYSFS") == 0) {
 326                         add_rule_key(rule, &rule->wait_for_sysfs, operation, value);
 327                         valid = 1;
 328                         continue;
 329                 }
 330
 331                 if (strncasecmp(key, "ENV", sizeof("ENV")-1) == 0) {
 332                         attr = get_key_attribute(key + sizeof("ENV")-1);
 333                         if (attr == NULL) {
 334                                 err("error parsing ENV attribute");
 335                                 continue;
 336                         }
 337                         add_rule_key_pair(rule, &rule->env, operation, attr, value);
 338                         valid = 1;
 339                         continue;
 340                 }
 341
 342                 if (strcasecmp(key, "MODALIAS") == 0) {
 343                         add_rule_key(rule, &rule->modalias, operation, value);
 344                         valid = 1;
 345                         continue;
 346                 }
 347
 348                 if (strncasecmp(key, "IMPORT", sizeof("IMPORT")-1) == 0) {
 349                         attr = get_key_attribute(key + sizeof("IMPORT")-1);
 350                         if (attr && strstr(attr, "program")) {
 351                                 dbg("IMPORT will be executed");
 352                                 rule->import_type  = IMPORT_PROGRAM;
 353                         } else if (attr && strstr(attr, "file")) {
 354                                 dbg("IMPORT will be included as file");
 355                                 rule->import_type  = IMPORT_FILE;
 356                         } else if (attr && strstr(attr, "parent")) {
 357                                 dbg("IMPORT will include the parent values");
 358                                 rule->import_type = IMPORT_PARENT;
 359                         } else {
 360                                 /* figure it out if it is executable */
 361                                 char file[PATH_SIZE];
 362                                 char *pos;
 363                                 struct stat stats;
 364
 365                                 strlcpy(file, value, sizeof(file));
 366                                 pos = strchr(file, ' ');
 367                                 if (pos)
 368                                         pos[0] = '\0';
 369                                 dbg("IMPORT auto mode for '%s'", file);
 370                                 if (!lstat(file, &stats) && (stats.st_mode & S_IXUSR)) {
 371                                         dbg("IMPORT is executable, will be executed (autotype)");
 372                                         rule->import_type  = IMPORT_PROGRAM;
 373                                 } else {
 374                                         dbg("IMPORT is not executable, will be included as file (autotype)");
 375                                         rule->import_type  = IMPORT_FILE;
 376                                 }
 377                         }
 378                         add_rule_key(rule, &rule->import, operation, value);
 379                         valid = 1;
 380                         continue;
 381                 }
 382
 383                 if (strcasecmp(key, "DRIVER") == 0) {
 384                         add_rule_key(rule, &rule->driver, operation, value);
 385                         valid = 1;
 386                         continue;
 387                 }
 388
 389                 if (strcasecmp(key, "RESULT") == 0) {
 390                         add_rule_key(rule, &rule->result, operation, value);
 391                         valid = 1;
 392                         continue;
 393                 }
 394
 395                 if (strcasecmp(key, "PROGRAM") == 0) {
 396                         add_rule_key(rule, &rule->program, operation, value);
 397                         valid = 1;
 398                         continue;
 399                 }
 400
 401                 if (strncasecmp(key, "NAME", sizeof("NAME")-1) == 0) {
 402                         attr = get_key_attribute(key + sizeof("NAME")-1);
 403                         if (attr != NULL) {
 404                                 if (strstr(attr, "all_partitions") != NULL) {
 405                                         dbg("creation of partition nodes requested");
 406                                         rule->partitions = DEFAULT_PARTITIONS_COUNT;
 407                                 }
 408                                 if (strstr(attr, "ignore_remove") != NULL) {
 409                                         dbg("remove event should be ignored");
 410                                         rule->ignore_remove = 1;
 411                                 }
 412                         }
 413                         if (value[0] == '\0')
 414                                 dbg("name empty, not creation supressed");
 415                         add_rule_key(rule, &rule->name, operation, value);
 416                         continue;
 417                 }
 418
 419                 if (strcasecmp(key, "SYMLINK") == 0) {
 420                         add_rule_key(rule, &rule->symlink, operation, value);
 421                         valid = 1;
 422                         continue;
 423                 }
 424
 425                 if (strcasecmp(key, "OWNER") == 0) {
 426                         valid = 1;
 427                         if (rules->resolve_names && (!strchr(value, '$') && !strchr(value, '%'))) {
 428                                 char *endptr;
 429                                 strtoul(value, &endptr, 10);
 430                                 if (endptr[0] != '\0') {
 431                                         char owner[32];
 432                                         uid_t uid = lookup_user(value);
 433                                         dbg("replacing username='%s' by id=%i", value, uid);
 434                                         sprintf(owner, "%u", (unsigned int) uid);
 435                                         add_rule_key(rule, &rule->owner, operation, owner);
 436                                         continue;
 437                                 }
 438                         }
 439
 440                         add_rule_key(rule, &rule->owner, operation, value);
 441                         continue;
 442                 }
 443
 444                 if (strcasecmp(key, "GROUP") == 0) {
 445                         valid = 1;
 446                         if (rules->resolve_names && (!strchr(value, '$') && !strchr(value, '%'))) {
 447                                 char *endptr;
 448                                 strtoul(value, &endptr, 10);
 449                                 if (endptr[0] != '\0') {
 450                                         char group[32];
 451                                         gid_t gid = lookup_group(value);
 452                                         dbg("replacing groupname='%s' by id=%i", value, gid);
 453                                         sprintf(group, "%u", (unsigned int) gid);
 454                                         add_rule_key(rule, &rule->group, operation, group);
 455                                         continue;
 456                                 }
 457                         }
 458
 459                         add_rule_key(rule, &rule->group, operation, value);
 460                         continue;
 461                 }
 462
 463                 if (strcasecmp(key, "MODE") == 0) {
 464                         rule->mode = strtol(value, NULL, 8);
 465                         rule->mode_operation = operation;
 466                         valid = 1;
 467                         continue;
 468                 }
 469
 470                 if (strcasecmp(key, "RUN") == 0) {
 471                         add_rule_key(rule, &rule->run, operation, value);
 472                         valid = 1;
 473                         continue;
 474                 }
 475
 476                 if (strcasecmp(key, "OPTIONS") == 0) {
 477                         if (strstr(value, "last_rule") != NULL) {
 478                                 dbg("last rule to be applied");
 479                                 rule->last_rule = 1;
 480                         }
 481                         if (strstr(value, "ignore_device") != NULL) {
 482                                 dbg("device should be ignored");
 483                                 rule->ignore_device = 1;
 484                         }
 485                         if (strstr(value, "ignore_remove") != NULL) {
 486                                 dbg("remove event should be ignored");
 487                                 rule->ignore_remove = 1;
 488                         }
 489                         if (strstr(value, "all_partitions") != NULL) {
 490                                 dbg("creation of partition nodes requested");
 491                                 rule->partitions = DEFAULT_PARTITIONS_COUNT;
 492                         }
 493                         valid = 1;
 494                         continue;
 495                 }
 496
 497                 err("unknown key '%s', in '%s'", key, line);
 498         }
 499
 500         /* skip line if not any valid key was found */
 501         if (!valid) {
 502                 err("invalid rule '%s'", line);
 503                 goto exit;
 504         }
 505
 506         /* grow buffer and add rule */
 507         rule_size = sizeof(struct udev_rule) + rule->bufsize;
 508         padding = (sizeof(size_t) - rule_size % sizeof(size_t)) % sizeof(size_t);
 509         dbg("add %zi padding bytes", padding);
 510         rule_size += padding;
 511         rule->bufsize += padding;
 512
 513         rules->buf = realloc(rules->buf, rules->bufsize + rule_size);
 514         if (!rules->buf) {
 515                 err("realloc failed");
 516                 goto exit;
 517         }
 518         dbg("adding rule to offset %zi", rules->bufsize);
 519         memcpy(rules->buf + rules->bufsize, rule, rule_size);
 520         rules->bufsize += rule_size;
 521 exit:
 522         free(rule);
 523         return 0;
 524 }
 525
 526 static int parse_file(struct udev_rules *rules, const char *filename)
 527 {
 528         char line[LINE_SIZE];
 529         char *bufline;
 530         int lineno;
 531         char *buf;
 532         size_t bufsize;
 533         size_t cur;
 534         size_t count;
 535         int retval = 0;
 536
 537         if (file_map(filename, &buf, &bufsize) != 0) {
 538                 err("can't open '%s' as rules file: %s", filename, strerror(errno));
 539                 return -1;
 540         }
 541         dbg("reading '%s' as rules file", filename);
 542
 543         /* loop through the whole file */
 544         cur = 0;
 545         lineno = 0;
 546         while (cur < bufsize) {
 547                 unsigned int i, j;
 548
 549                 count = buf_get_line(buf, bufsize, cur);
 550                 bufline = &buf[cur];
 551                 cur += count+1;
 552                 lineno++;
 553
 554                 if (count >= sizeof(line)) {
 555                         info("line too long, rule skipped %s, line %d", filename, lineno);
 556                         continue;
 557                 }
 558
 559                 /* eat the whitespace */
 560                 while ((count > 0) && isspace(bufline[0])) {
 561                         bufline++;
 562                         count--;
 563                 }
 564                 if (count == 0)
 565                         continue;
 566
 567                 /* see if this is a comment */
 568                 if (bufline[0] == COMMENT_CHARACTER)
 569                         continue;
 570
 571                 /* skip backslash and newline from multi line rules */
 572                 for (i = j = 0; i < count; i++) {
 573                         if (bufline[i] == '\\' && bufline[i+1] == '\n')
 574                                 continue;
 575
 576                         line[j++] = bufline[i];
 577                 }
 578                 line[j] = '\0';
 579
 580                 dbg("read '%s'", line);
 581                 add_to_rules(rules, line);
 582         }
 583
 584         file_unmap(buf, bufsize);
 585         return retval;
 586 }
 587
 588 int udev_rules_init(struct udev_rules *rules, int resolve_names)
 589 {
 590         struct stat stats;
 591         int retval;
 592
 593         memset(rules, 0x00, sizeof(struct udev_rules));
 594         rules->resolve_names = resolve_names;
 595
 596         /* parse rules file or all matching files in directory */
 597         if (stat(udev_rules_filename, &stats) != 0)
 598                 return -1;
 599
 600         if ((stats.st_mode & S_IFMT) != S_IFDIR) {
 601                 dbg("parse single rules file '%s'", udev_rules_filename);
 602                 retval = parse_file(rules, udev_rules_filename);
 603         } else {
 604                 struct name_entry *name_loop, *name_tmp;
 605                 LIST_HEAD(name_list);
 606
 607                 dbg("parse rules directory '%s'", udev_rules_filename);
 608                 retval = add_matching_files(&name_list, udev_rules_filename, RULEFILE_SUFFIX);
 609
 610                 list_for_each_entry_safe(name_loop, name_tmp, &name_list, node) {
 611                         if (stat(name_loop->name, &stats) == 0) {
 612                                 if (stats.st_size)
 613                                         parse_file(rules, name_loop->name);
 614                                 else
 615                                         dbg("empty rules file '%s'", name_loop->name);
 616                         } else
 617                                 err("could not read '%s': %s", name_loop->name, strerror(errno));
 618                         list_del(&name_loop->node);
 619                         free(name_loop);
 620                 }
 621         }
 622
 623         return retval;
 624 }
 625
 626 void udev_rules_cleanup(struct udev_rules *rules)
 627 {
 628         if (rules->buf) {
 629                 free(rules->buf);
 630                 rules->buf = NULL;
 631         }
 632 }