src/mod_rewrite.c

   1 #include "first.h"
   2
   3 #include "base.h"
   4 #include "log.h"
   5 #include "buffer.h"
   6
   7 #include "plugin.h"
   8 #include "stat_cache.h"
   9
  10 #include <ctype.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #ifdef HAVE_PCRE_H
  15 typedef struct {
  16         pcre *key;
  17
  18         buffer *value;
  19
  20         int once;
  21 } rewrite_rule;
  22
  23 typedef struct {
  24         rewrite_rule **ptr;
  25
  26         size_t used;
  27         size_t size;
  28 } rewrite_rule_buffer;
  29
  30 typedef struct {
  31         rewrite_rule_buffer *rewrite;
  32         rewrite_rule_buffer *rewrite_NF;
  33         data_config *context, *context_NF; /* to which apply me */
  34 } plugin_config;
  35
  36 typedef struct {
  37         enum { REWRITE_STATE_UNSET, REWRITE_STATE_FINISHED} state;
  38         int loops;
  39 } handler_ctx;
  40
  41 typedef struct {
  42         PLUGIN_DATA;
  43         buffer *match_buf;
  44
  45         plugin_config **config_storage;
  46
  47         plugin_config conf;
  48 } plugin_data;
  49
  50 static handler_ctx * handler_ctx_init(void) {
  51         handler_ctx * hctx;
  52
  53         hctx = calloc(1, sizeof(*hctx));
  54
  55         hctx->state = REWRITE_STATE_UNSET;
  56         hctx->loops = 0;
  57
  58         return hctx;
  59 }
  60
  61 static void handler_ctx_free(handler_ctx *hctx) {
  62         free(hctx);
  63 }
  64
  65 static rewrite_rule_buffer *rewrite_rule_buffer_init(void) {
  66         rewrite_rule_buffer *kvb;
  67
  68         kvb = calloc(1, sizeof(*kvb));
  69
  70         return kvb;
  71 }
  72
  73 static int rewrite_rule_buffer_append(rewrite_rule_buffer *kvb, buffer *key, buffer *value, int once) {
  74         size_t i;
  75         const char *errptr;
  76         int erroff;
  77
  78         if (!key) return -1;
  79
  80         if (kvb->size == 0) {
  81                 kvb->size = 4;
  82                 kvb->used = 0;
  83
  84                 kvb->ptr = malloc(kvb->size * sizeof(*kvb->ptr));
  85
  86                 for(i = 0; i < kvb->size; i++) {
  87                         kvb->ptr[i] = calloc(1, sizeof(**kvb->ptr));
  88                 }
  89         } else if (kvb->used == kvb->size) {
  90                 kvb->size += 4;
  91
  92                 kvb->ptr = realloc(kvb->ptr, kvb->size * sizeof(*kvb->ptr));
  93
  94                 for(i = kvb->used; i < kvb->size; i++) {
  95                         kvb->ptr[i] = calloc(1, sizeof(**kvb->ptr));
  96                 }
  97         }
  98
  99         if (NULL == (kvb->ptr[kvb->used]->key = pcre_compile(key->ptr,
 100                                                             0, &errptr, &erroff, NULL))) {
 101
 102                 return -1;
 103         }
 104
 105         kvb->ptr[kvb->used]->value = buffer_init();
 106         buffer_copy_buffer(kvb->ptr[kvb->used]->value, value);
 107         kvb->ptr[kvb->used]->once = once;
 108
 109         kvb->used++;
 110
 111         return 0;
 112 }
 113
 114 static void rewrite_rule_buffer_free(rewrite_rule_buffer *kvb) {
 115         size_t i;
 116
 117         for (i = 0; i < kvb->size; i++) {
 118                 if (kvb->ptr[i]->key) pcre_free(kvb->ptr[i]->key);
 119                 if (kvb->ptr[i]->value) buffer_free(kvb->ptr[i]->value);
 120                 free(kvb->ptr[i]);
 121         }
 122
 123         if (kvb->ptr) free(kvb->ptr);
 124
 125         free(kvb);
 126 }
 127
 128
 129 INIT_FUNC(mod_rewrite_init) {
 130         plugin_data *p;
 131
 132         p = calloc(1, sizeof(*p));
 133
 134         p->match_buf = buffer_init();
 135
 136         return p;
 137 }
 138
 139 FREE_FUNC(mod_rewrite_free) {
 140         plugin_data *p = p_d;
 141
 142         UNUSED(srv);
 143
 144         if (!p) return HANDLER_GO_ON;
 145
 146         buffer_free(p->match_buf);
 147         if (p->config_storage) {
 148                 size_t i;
 149                 for (i = 0; i < srv->config_context->used; i++) {
 150                         plugin_config *s = p->config_storage[i];
 151
 152                         if (NULL == s) continue;
 153
 154                         rewrite_rule_buffer_free(s->rewrite);
 155                         rewrite_rule_buffer_free(s->rewrite_NF);
 156
 157                         free(s);
 158                 }
 159                 free(p->config_storage);
 160         }
 161
 162         free(p);
 163
 164         return HANDLER_GO_ON;
 165 }
 166
 167 static int parse_config_entry(server *srv, array *ca, rewrite_rule_buffer *kvb, const char *option, int once) {
 168         data_unset *du;
 169
 170         if (NULL != (du = array_get_element(ca, option))) {
 171                 data_array *da;
 172                 size_t j;
 173
 174                 if (du->type != TYPE_ARRAY) {
 175                         log_error_write(srv, __FILE__, __LINE__, "sss",
 176                                         "unexpected type for key: ", option, "array of strings");
 177
 178                         return HANDLER_ERROR;
 179                 }
 180
 181                 da = (data_array *)du;
 182
 183                 for (j = 0; j < da->value->used; j++) {
 184                         if (da->value->data[j]->type != TYPE_STRING) {
 185                                 log_error_write(srv, __FILE__, __LINE__, "sssbs",
 186                                                 "unexpected type for key: ",
 187                                                 option,
 188                                                 "[", da->value->data[j]->key, "](string)");
 189
 190                                 return HANDLER_ERROR;
 191                         }
 192
 193                         if (0 != rewrite_rule_buffer_append(kvb,
 194                                                             ((data_string *)(da->value->data[j]))->key,
 195                                                             ((data_string *)(da->value->data[j]))->value,
 196                                                             once)) {
 197                                 log_error_write(srv, __FILE__, __LINE__, "sb",
 198                                                 "pcre-compile failed for", da->value->data[j]->key);
 199                                 return HANDLER_ERROR;
 200                         }
 201                 }
 202         }
 203
 204         return 0;
 205 }
 206 #else
 207 static int parse_config_entry(server *srv, array *ca, const char *option) {
 208         static int logged_message = 0;
 209         if (logged_message) return 0;
 210         if (NULL != array_get_element(ca, option)) {
 211                 logged_message = 1;
 212                 log_error_write(srv, __FILE__, __LINE__, "s",
 213                         "pcre support is missing, please install libpcre and the headers");
 214         }
 215         return 0;
 216 }
 217 #endif
 218
 219 SETDEFAULTS_FUNC(mod_rewrite_set_defaults) {
 220         size_t i = 0;
 221         config_values_t cv[] = {
 222                 { "url.rewrite-repeat",        NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 0 */
 223                 { "url.rewrite-once",          NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 1 */
 224
 225                 /* these functions only rewrite if the target is not already in the filestore
 226                  *
 227                  * url.rewrite-repeat-if-not-file is the equivalent of url.rewrite-repeat
 228                  * url.rewrite-if-not-file is the equivalent of url.rewrite-once
 229                  *
 230                  */
 231                 { "url.rewrite-repeat-if-not-file", NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 2 */
 232                 { "url.rewrite-if-not-file",        NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 3 */
 233
 234                 /* old names, still supported
 235                  *
 236                  * url.rewrite remapped to url.rewrite-once
 237                  * url.rewrite-final    is url.rewrite-once
 238                  *
 239                  */
 240                 { "url.rewrite",               NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 4 */
 241                 { "url.rewrite-final",         NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 5 */
 242                 { NULL,                        NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
 243         };
 244
 245 #ifdef HAVE_PCRE_H
 246         plugin_data *p = p_d;
 247
 248         if (!p) return HANDLER_ERROR;
 249
 250         /* 0 */
 251         p->config_storage = calloc(1, srv->config_context->used * sizeof(plugin_config *));
 252 #else
 253         UNUSED(p_d);
 254 #endif
 255
 256         for (i = 0; i < srv->config_context->used; i++) {
 257                 data_config const* config = (data_config const*)srv->config_context->data[i];
 258 #ifdef HAVE_PCRE_H
 259                 plugin_config *s;
 260
 261                 s = calloc(1, sizeof(plugin_config));
 262                 s->rewrite = rewrite_rule_buffer_init();
 263                 s->rewrite_NF = rewrite_rule_buffer_init();
 264                 p->config_storage[i] = s;
 265 #endif
 266
 267                 if (0 != config_insert_values_global(srv, config->value, cv, i == 0 ? T_CONFIG_SCOPE_SERVER : T_CONFIG_SCOPE_CONNECTION)) {
 268                         return HANDLER_ERROR;
 269                 }
 270
 271 #ifndef HAVE_PCRE_H
 272 # define parse_config_entry(srv, ca, x, option, y) parse_config_entry(srv, ca, option)
 273 #endif
 274                 parse_config_entry(srv, config->value, s->rewrite, "url.rewrite-once",      1);
 275                 parse_config_entry(srv, config->value, s->rewrite, "url.rewrite-final",     1);
 276                 parse_config_entry(srv, config->value, s->rewrite_NF, "url.rewrite-if-not-file",   1);
 277                 parse_config_entry(srv, config->value, s->rewrite_NF, "url.rewrite-repeat-if-not-file", 0);
 278                 parse_config_entry(srv, config->value, s->rewrite, "url.rewrite",           1);
 279                 parse_config_entry(srv, config->value, s->rewrite, "url.rewrite-repeat",    0);
 280         }
 281
 282         return HANDLER_GO_ON;
 283 }
 284
 285 #ifdef HAVE_PCRE_H
 286
 287 #define PATCH(x) \
 288         p->conf.x = s->x;
 289 static int mod_rewrite_patch_connection(server *srv, connection *con, plugin_data *p) {
 290         size_t i, j;
 291         plugin_config *s = p->config_storage[0];
 292
 293         PATCH(rewrite);
 294         PATCH(rewrite_NF);
 295         p->conf.context = NULL;
 296         p->conf.context_NF = NULL;
 297
 298         /* skip the first, the global context */
 299         for (i = 1; i < srv->config_context->used; i++) {
 300                 data_config *dc = (data_config *)srv->config_context->data[i];
 301                 s = p->config_storage[i];
 302
 303                 /* condition didn't match */
 304                 if (!config_check_cond(srv, con, dc)) continue;
 305
 306                 /* merge config */
 307                 for (j = 0; j < dc->value->used; j++) {
 308                         data_unset *du = dc->value->data[j];
 309
 310                         if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite"))) {
 311                                 PATCH(rewrite);
 312                                 p->conf.context = dc;
 313                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-once"))) {
 314                                 PATCH(rewrite);
 315                                 p->conf.context = dc;
 316                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-repeat"))) {
 317                                 PATCH(rewrite);
 318                                 p->conf.context = dc;
 319                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-if-not-file"))) {
 320                                 PATCH(rewrite_NF);
 321                                 p->conf.context_NF = dc;
 322                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-repeat-if-not-file"))) {
 323                                 PATCH(rewrite_NF);
 324                                 p->conf.context_NF = dc;
 325                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-final"))) {
 326                                 PATCH(rewrite);
 327                                 p->conf.context = dc;
 328                         }
 329                 }
 330         }
 331
 332         return 0;
 333 }
 334
 335 URIHANDLER_FUNC(mod_rewrite_con_reset) {
 336         plugin_data *p = p_d;
 337
 338         UNUSED(srv);
 339
 340         if (con->plugin_ctx[p->id]) {
 341                 handler_ctx_free(con->plugin_ctx[p->id]);
 342                 con->plugin_ctx[p->id] = NULL;
 343         }
 344
 345         return HANDLER_GO_ON;
 346 }
 347
 348 static handler_t process_rewrite_rules(server *srv, connection *con, plugin_data *p, rewrite_rule_buffer *kvb) {
 349         size_t i;
 350         handler_ctx *hctx;
 351
 352         if (con->plugin_ctx[p->id]) {
 353                 hctx = con->plugin_ctx[p->id];
 354
 355                 if (hctx->loops++ > 100) {
 356                         data_config *dc = p->conf.context;
 357                         log_error_write(srv, __FILE__, __LINE__,  "SbbSBS",
 358                                         "ENDLESS LOOP IN rewrite-rule DETECTED ... aborting request, perhaps you want to use url.rewrite-once instead of url.rewrite-repeat ($", dc->comp_key, dc->op, "\"", dc->string, "\")");
 359
 360                         return HANDLER_ERROR;
 361                 }
 362
 363                 if (hctx->state == REWRITE_STATE_FINISHED) return HANDLER_GO_ON;
 364         }
 365
 366         buffer_copy_buffer(p->match_buf, con->request.uri);
 367
 368         for (i = 0; i < kvb->used; i++) {
 369                 pcre *match;
 370                 const char *pattern;
 371                 size_t pattern_len;
 372                 int n;
 373                 rewrite_rule *rule = kvb->ptr[i];
 374 # define N 10
 375                 int ovec[N * 3];
 376
 377                 match       = rule->key;
 378                 pattern     = rule->value->ptr;
 379                 pattern_len = buffer_string_length(rule->value);
 380
 381                 if ((n = pcre_exec(match, NULL, CONST_BUF_LEN(p->match_buf), 0, 0, ovec, 3 * N)) < 0) {
 382                         if (n != PCRE_ERROR_NOMATCH) {
 383                                 log_error_write(srv, __FILE__, __LINE__, "sd",
 384                                                 "execution error while matching: ", n);
 385                                 return HANDLER_ERROR;
 386                         }
 387                 } else if (0 == pattern_len) {
 388                         /* short-circuit if blank replacement pattern
 389                          * (do not attempt to match against remaining rewrite rules) */
 390                         return HANDLER_GO_ON;
 391                 } else {
 392                         const char **list;
 393                         size_t start;
 394                         size_t k;
 395
 396                         /* it matched */
 397                         pcre_get_substring_list(p->match_buf->ptr, ovec, n, &list);
 398
 399                         /* search for $[0-9] */
 400
 401                         buffer_reset(con->request.uri);
 402
 403                         start = 0;
 404                         for (k = 0; k+1 < pattern_len; k++) {
 405                                 if (pattern[k] == '$' || pattern[k] == '%') {
 406                                         /* got one */
 407
 408                                         size_t num = pattern[k + 1] - '0';
 409
 410                                         buffer_append_string_len(con->request.uri, pattern + start, k - start);
 411
 412                                         if (!isdigit((unsigned char)pattern[k + 1])) {
 413                                                 /* enable escape: "%%" => "%", "%a" => "%a", "$$" => "$" */
 414                                                 buffer_append_string_len(con->request.uri, pattern+k, pattern[k] == pattern[k+1] ? 1 : 2);
 415                                         } else if (pattern[k] == '$') {
 416                                                 /* n is always > 0 */
 417                                                 if (num < (size_t)n) {
 418                                                         buffer_append_string(con->request.uri, list[num]);
 419                                                 }
 420                                         } else if (p->conf.context == NULL) {
 421                                                 /* we have no context, we are global */
 422                                                 log_error_write(srv, __FILE__, __LINE__, "sb",
 423                                                                 "used a redirect containing a %[0-9]+ in the global scope, ignored:",
 424                                                                 rule->value);
 425
 426                                         } else {
 427                                                 config_append_cond_match_buffer(con, p->conf.context, con->request.uri, num);
 428                                         }
 429
 430                                         k++;
 431                                         start = k + 1;
 432                                 }
 433                         }
 434
 435                         buffer_append_string_len(con->request.uri, pattern + start, pattern_len - start);
 436
 437                         pcre_free(list);
 438
 439                         if (con->plugin_ctx[p->id] == NULL) {
 440                                 hctx = handler_ctx_init();
 441                                 con->plugin_ctx[p->id] = hctx;
 442                         } else {
 443                                 hctx = con->plugin_ctx[p->id];
 444                         }
 445
 446                         if (rule->once) hctx->state = REWRITE_STATE_FINISHED;
 447
 448                         return HANDLER_COMEBACK;
 449                 }
 450 #undef N
 451         }
 452
 453         return HANDLER_GO_ON;
 454 }
 455
 456 URIHANDLER_FUNC(mod_rewrite_physical) {
 457         plugin_data *p = p_d;
 458         handler_t r;
 459         stat_cache_entry *sce;
 460
 461         if (con->mode != DIRECT) return HANDLER_GO_ON;
 462
 463         mod_rewrite_patch_connection(srv, con, p);
 464         p->conf.context = p->conf.context_NF;
 465
 466         if (!p->conf.rewrite_NF) return HANDLER_GO_ON;
 467
 468         /* skip if physical.path is a regular file */
 469         sce = NULL;
 470         if (HANDLER_ERROR != stat_cache_get_entry(srv, con, con->physical.path, &sce)) {
 471                 if (S_ISREG(sce->st.st_mode)) return HANDLER_GO_ON;
 472         }
 473
 474         switch(r = process_rewrite_rules(srv, con, p, p->conf.rewrite_NF)) {
 475         case HANDLER_COMEBACK:
 476                 buffer_reset(con->physical.path);
 477         default:
 478                 return r;
 479         }
 480
 481         return HANDLER_GO_ON;
 482 }
 483
 484 URIHANDLER_FUNC(mod_rewrite_uri_handler) {
 485         plugin_data *p = p_d;
 486
 487         mod_rewrite_patch_connection(srv, con, p);
 488
 489         if (!p->conf.rewrite) return HANDLER_GO_ON;
 490
 491         return process_rewrite_rules(srv, con, p, p->conf.rewrite);
 492 }
 493 #endif
 494
 495 int mod_rewrite_plugin_init(plugin *p);
 496 int mod_rewrite_plugin_init(plugin *p) {
 497         p->version     = LIGHTTPD_VERSION_ID;
 498         p->name        = buffer_init_string("rewrite");
 499
 500 #ifdef HAVE_PCRE_H
 501         p->init        = mod_rewrite_init;
 502         /* it has to stay _raw as we are matching on uri + querystring
 503          */
 504
 505         p->handle_uri_raw = mod_rewrite_uri_handler;
 506         p->handle_physical = mod_rewrite_physical;
 507         p->cleanup     = mod_rewrite_free;
 508         p->connection_reset = mod_rewrite_con_reset;
 509 #endif
 510         p->set_defaults = mod_rewrite_set_defaults;
 511
 512         p->data        = NULL;
 513
 514         return 0;
 515 }