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, size_t olen, int once) {
 168         data_unset *du;
 169
 170         if (NULL != (du = array_get_element_klen(ca, option, olen))) {
 171                 data_array *da;
 172                 size_t j;
 173
 174                 da = (data_array *)du;
 175
 176                 if (du->type != TYPE_ARRAY || !array_is_kvstring(da->value)) {
 177                         log_error_write(srv, __FILE__, __LINE__, "SSS",
 178                                         "unexpected value for ", option, "; expected list of \"regex\" => \"subst\"");
 179                         return HANDLER_ERROR;
 180                 }
 181
 182                 for (j = 0; j < da->value->used; j++) {
 183                         if (0 != rewrite_rule_buffer_append(kvb,
 184                                                             ((data_string *)(da->value->data[j]))->key,
 185                                                             ((data_string *)(da->value->data[j]))->value,
 186                                                             once)) {
 187                                 log_error_write(srv, __FILE__, __LINE__, "sb",
 188                                                 "pcre-compile failed for", da->value->data[j]->key);
 189                                 return HANDLER_ERROR;
 190                         }
 191                 }
 192         }
 193
 194         return 0;
 195 }
 196 #else
 197 static int parse_config_entry(server *srv, array *ca, const char *option, size_t olen) {
 198         static int logged_message = 0;
 199         if (logged_message) return 0;
 200         if (NULL != array_get_element_klen(ca, option, olen)) {
 201                 logged_message = 1;
 202                 log_error_write(srv, __FILE__, __LINE__, "s",
 203                         "pcre support is missing, please install libpcre and the headers");
 204         }
 205         return 0;
 206 }
 207 #endif
 208
 209 SETDEFAULTS_FUNC(mod_rewrite_set_defaults) {
 210         size_t i = 0;
 211         config_values_t cv[] = {
 212                 { "url.rewrite-repeat",        NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 0 */
 213                 { "url.rewrite-once",          NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 1 */
 214
 215                 /* these functions only rewrite if the target is not already in the filestore
 216                  *
 217                  * url.rewrite-repeat-if-not-file is the equivalent of url.rewrite-repeat
 218                  * url.rewrite-if-not-file is the equivalent of url.rewrite-once
 219                  *
 220                  */
 221                 { "url.rewrite-repeat-if-not-file", NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 2 */
 222                 { "url.rewrite-if-not-file",        NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 3 */
 223
 224                 /* old names, still supported
 225                  *
 226                  * url.rewrite remapped to url.rewrite-once
 227                  * url.rewrite-final    is url.rewrite-once
 228                  *
 229                  */
 230                 { "url.rewrite",               NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 4 */
 231                 { "url.rewrite-final",         NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION }, /* 5 */
 232                 { NULL,                        NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
 233         };
 234
 235 #ifdef HAVE_PCRE_H
 236         plugin_data *p = p_d;
 237
 238         if (!p) return HANDLER_ERROR;
 239
 240         /* 0 */
 241         p->config_storage = calloc(1, srv->config_context->used * sizeof(plugin_config *));
 242 #else
 243         UNUSED(p_d);
 244 #endif
 245
 246         for (i = 0; i < srv->config_context->used; i++) {
 247                 data_config const* config = (data_config const*)srv->config_context->data[i];
 248 #ifdef HAVE_PCRE_H
 249                 plugin_config *s;
 250
 251                 s = calloc(1, sizeof(plugin_config));
 252                 s->rewrite = rewrite_rule_buffer_init();
 253                 s->rewrite_NF = rewrite_rule_buffer_init();
 254                 p->config_storage[i] = s;
 255 #endif
 256
 257                 if (0 != config_insert_values_global(srv, config->value, cv, i == 0 ? T_CONFIG_SCOPE_SERVER : T_CONFIG_SCOPE_CONNECTION)) {
 258                         return HANDLER_ERROR;
 259                 }
 260
 261 #ifndef HAVE_PCRE_H
 262 # define parse_config_entry(srv, ca, x, option, y) parse_config_entry(srv, ca, option)
 263 #endif
 264                 parse_config_entry(srv, config->value, s->rewrite, CONST_STR_LEN("url.rewrite-once"),      1);
 265                 parse_config_entry(srv, config->value, s->rewrite, CONST_STR_LEN("url.rewrite-final"),     1);
 266                 parse_config_entry(srv, config->value, s->rewrite_NF, CONST_STR_LEN("url.rewrite-if-not-file"),   1);
 267                 parse_config_entry(srv, config->value, s->rewrite_NF, CONST_STR_LEN("url.rewrite-repeat-if-not-file"), 0);
 268                 parse_config_entry(srv, config->value, s->rewrite, CONST_STR_LEN("url.rewrite"),           1);
 269                 parse_config_entry(srv, config->value, s->rewrite, CONST_STR_LEN("url.rewrite-repeat"),    0);
 270         }
 271
 272         return HANDLER_GO_ON;
 273 }
 274
 275 #ifdef HAVE_PCRE_H
 276
 277 #define PATCH(x) \
 278         p->conf.x = s->x;
 279 static int mod_rewrite_patch_connection(server *srv, connection *con, plugin_data *p) {
 280         size_t i, j;
 281         plugin_config *s = p->config_storage[0];
 282
 283         PATCH(rewrite);
 284         PATCH(rewrite_NF);
 285         p->conf.context = NULL;
 286         p->conf.context_NF = NULL;
 287
 288         /* skip the first, the global context */
 289         for (i = 1; i < srv->config_context->used; i++) {
 290                 data_config *dc = (data_config *)srv->config_context->data[i];
 291                 s = p->config_storage[i];
 292
 293                 /* condition didn't match */
 294                 if (!config_check_cond(srv, con, dc)) continue;
 295
 296                 /* merge config */
 297                 for (j = 0; j < dc->value->used; j++) {
 298                         data_unset *du = dc->value->data[j];
 299
 300                         if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite"))) {
 301                                 PATCH(rewrite);
 302                                 p->conf.context = dc;
 303                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-once"))) {
 304                                 PATCH(rewrite);
 305                                 p->conf.context = dc;
 306                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-repeat"))) {
 307                                 PATCH(rewrite);
 308                                 p->conf.context = dc;
 309                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-if-not-file"))) {
 310                                 PATCH(rewrite_NF);
 311                                 p->conf.context_NF = dc;
 312                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-repeat-if-not-file"))) {
 313                                 PATCH(rewrite_NF);
 314                                 p->conf.context_NF = dc;
 315                         } else if (buffer_is_equal_string(du->key, CONST_STR_LEN("url.rewrite-final"))) {
 316                                 PATCH(rewrite);
 317                                 p->conf.context = dc;
 318                         }
 319                 }
 320         }
 321
 322         return 0;
 323 }
 324
 325 URIHANDLER_FUNC(mod_rewrite_con_reset) {
 326         plugin_data *p = p_d;
 327
 328         UNUSED(srv);
 329
 330         if (con->plugin_ctx[p->id]) {
 331                 handler_ctx_free(con->plugin_ctx[p->id]);
 332                 con->plugin_ctx[p->id] = NULL;
 333         }
 334
 335         return HANDLER_GO_ON;
 336 }
 337
 338 static handler_t process_rewrite_rules(server *srv, connection *con, plugin_data *p, rewrite_rule_buffer *kvb) {
 339         size_t i;
 340         handler_ctx *hctx;
 341
 342         if (con->plugin_ctx[p->id]) {
 343                 hctx = con->plugin_ctx[p->id];
 344
 345                 if (hctx->loops++ > 100) {
 346                         data_config *dc = p->conf.context;
 347                         log_error_write(srv, __FILE__, __LINE__,  "SbbSBS",
 348                                         "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, "\")");
 349
 350                         return HANDLER_ERROR;
 351                 }
 352
 353                 if (hctx->state == REWRITE_STATE_FINISHED) return HANDLER_GO_ON;
 354         }
 355
 356         buffer_copy_buffer(p->match_buf, con->request.uri);
 357
 358         for (i = 0; i < kvb->used; i++) {
 359                 pcre *match;
 360                 const char *pattern;
 361                 size_t pattern_len;
 362                 int n;
 363                 rewrite_rule *rule = kvb->ptr[i];
 364 # define N 10
 365                 int ovec[N * 3];
 366
 367                 match       = rule->key;
 368                 pattern     = rule->value->ptr;
 369                 pattern_len = buffer_string_length(rule->value);
 370
 371                 if ((n = pcre_exec(match, NULL, CONST_BUF_LEN(p->match_buf), 0, 0, ovec, 3 * N)) < 0) {
 372                         if (n != PCRE_ERROR_NOMATCH) {
 373                                 log_error_write(srv, __FILE__, __LINE__, "sd",
 374                                                 "execution error while matching: ", n);
 375                                 return HANDLER_ERROR;
 376                         }
 377                 } else if (0 == pattern_len) {
 378                         /* short-circuit if blank replacement pattern
 379                          * (do not attempt to match against remaining rewrite rules) */
 380                         return HANDLER_GO_ON;
 381                 } else {
 382                         const char **list;
 383                         size_t start;
 384                         size_t k;
 385
 386                         /* it matched */
 387                         pcre_get_substring_list(p->match_buf->ptr, ovec, n, &list);
 388
 389                         /* search for $[0-9] */
 390
 391                         buffer_reset(con->request.uri);
 392
 393                         start = 0;
 394                         for (k = 0; k+1 < pattern_len; k++) {
 395                                 if (pattern[k] == '$' || pattern[k] == '%') {
 396                                         /* got one */
 397
 398                                         size_t num = pattern[k + 1] - '0';
 399
 400                                         buffer_append_string_len(con->request.uri, pattern + start, k - start);
 401
 402                                         if (!isdigit((unsigned char)pattern[k + 1])) {
 403                                                 /* enable escape: "%%" => "%", "%a" => "%a", "$$" => "$" */
 404                                                 buffer_append_string_len(con->request.uri, pattern+k, pattern[k] == pattern[k+1] ? 1 : 2);
 405                                         } else if (pattern[k] == '$') {
 406                                                 /* n is always > 0 */
 407                                                 if (num < (size_t)n) {
 408                                                         buffer_append_string(con->request.uri, list[num]);
 409                                                 }
 410                                         } else if (p->conf.context == NULL) {
 411                                                 /* we have no context, we are global */
 412                                                 log_error_write(srv, __FILE__, __LINE__, "sb",
 413                                                                 "used a redirect containing a %[0-9]+ in the global scope, ignored:",
 414                                                                 rule->value);
 415
 416                                         } else {
 417                                                 config_append_cond_match_buffer(con, p->conf.context, con->request.uri, num);
 418                                         }
 419
 420                                         k++;
 421                                         start = k + 1;
 422                                 }
 423                         }
 424
 425                         buffer_append_string_len(con->request.uri, pattern + start, pattern_len - start);
 426
 427                         pcre_free(list);
 428
 429                         if (con->plugin_ctx[p->id] == NULL) {
 430                                 hctx = handler_ctx_init();
 431                                 con->plugin_ctx[p->id] = hctx;
 432                         } else {
 433                                 hctx = con->plugin_ctx[p->id];
 434                         }
 435
 436                         if (rule->once) hctx->state = REWRITE_STATE_FINISHED;
 437
 438                         return HANDLER_COMEBACK;
 439                 }
 440 #undef N
 441         }
 442
 443         return HANDLER_GO_ON;
 444 }
 445
 446 URIHANDLER_FUNC(mod_rewrite_physical) {
 447         plugin_data *p = p_d;
 448         handler_t r;
 449         stat_cache_entry *sce;
 450
 451         if (con->mode != DIRECT) return HANDLER_GO_ON;
 452
 453         mod_rewrite_patch_connection(srv, con, p);
 454         p->conf.context = p->conf.context_NF;
 455
 456         if (!p->conf.rewrite_NF) return HANDLER_GO_ON;
 457
 458         /* skip if physical.path is a regular file */
 459         sce = NULL;
 460         if (HANDLER_ERROR != stat_cache_get_entry(srv, con, con->physical.path, &sce)) {
 461                 if (S_ISREG(sce->st.st_mode)) return HANDLER_GO_ON;
 462         }
 463
 464         switch(r = process_rewrite_rules(srv, con, p, p->conf.rewrite_NF)) {
 465         case HANDLER_COMEBACK:
 466                 buffer_reset(con->physical.path);
 467                 /* fall through */
 468         default:
 469                 return r;
 470         }
 471
 472         return HANDLER_GO_ON;
 473 }
 474
 475 URIHANDLER_FUNC(mod_rewrite_uri_handler) {
 476         plugin_data *p = p_d;
 477
 478         mod_rewrite_patch_connection(srv, con, p);
 479
 480         if (!p->conf.rewrite) return HANDLER_GO_ON;
 481
 482         return process_rewrite_rules(srv, con, p, p->conf.rewrite);
 483 }
 484 #endif
 485
 486 int mod_rewrite_plugin_init(plugin *p);
 487 int mod_rewrite_plugin_init(plugin *p) {
 488         p->version     = LIGHTTPD_VERSION_ID;
 489         p->name        = buffer_init_string("rewrite");
 490
 491 #ifdef HAVE_PCRE_H
 492         p->init        = mod_rewrite_init;
 493         /* it has to stay _raw as we are matching on uri + querystring
 494          */
 495
 496         p->handle_uri_raw = mod_rewrite_uri_handler;
 497         p->handle_physical = mod_rewrite_physical;
 498         p->cleanup     = mod_rewrite_free;
 499         p->connection_reset = mod_rewrite_con_reset;
 500 #endif
 501         p->set_defaults = mod_rewrite_set_defaults;
 502
 503         p->data        = NULL;
 504
 505         return 0;
 506 }