file.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2013 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #define _BSD_SOURCE
  21 #define _DARWIN_C_SOURCE
  22 #define _XOPEN_SOURCE 700
  23
  24 #include <sys/types.h>
  25 #include <sys/dir.h>
  26 #include <time.h>
  27 #include <strings.h>
  28 #include <dirent.h>
  29
  30 #include <libubox/blobmsg.h>
  31
  32 #include "uhttpd.h"
  33 #include "mimetypes.h"
  34
  35 static LIST_HEAD(index_files);
  36 static LIST_HEAD(dispatch_handlers);
  37 static LIST_HEAD(pending_requests);
  38 static int n_requests;
  39
  40 struct deferred_request {
  41         struct list_head list;
  42         struct dispatch_handler *d;
  43         struct client *cl;
  44         struct path_info pi;
  45         bool called, path;
  46 };
  47
  48 struct index_file {
  49         struct list_head list;
  50         const char *name;
  51 };
  52
  53 enum file_hdr {
  54         HDR_AUTHORIZATION,
  55         HDR_IF_MODIFIED_SINCE,
  56         HDR_IF_UNMODIFIED_SINCE,
  57         HDR_IF_MATCH,
  58         HDR_IF_NONE_MATCH,
  59         HDR_IF_RANGE,
  60         __HDR_MAX
  61 };
  62
  63 void uh_index_add(const char *filename)
  64 {
  65         struct index_file *idx;
  66
  67         idx = calloc(1, sizeof(*idx));
  68         idx->name = filename;
  69         list_add_tail(&idx->list, &index_files);
  70 }
  71
  72 static char * canonpath(const char *path, char *path_resolved)
  73 {
  74         const char *path_cpy = path;
  75         char *path_res = path_resolved;
  76
  77         if (conf.no_symlinks)
  78                 return realpath(path, path_resolved);
  79
  80         /* normalize */
  81         while ((*path_cpy != '\0') && (path_cpy < (path + PATH_MAX - 2))) {
  82                 if (*path_cpy != '/')
  83                         goto next;
  84
  85                 /* skip repeating / */
  86                 if (path_cpy[1] == '/') {
  87                         path_cpy++;
  88                         continue;
  89                 }
  90
  91                 /* /./ or /../ */
  92                 if (path_cpy[1] == '.') {
  93                         /* skip /./ */
  94                         if ((path_cpy[2] == '/') || (path_cpy[2] == '\0')) {
  95                                 path_cpy += 2;
  96                                 continue;
  97                         }
  98
  99                         /* collapse /x/../ */
 100                         if ((path_cpy[2] == '.') &&
 101                             ((path_cpy[3] == '/') || (path_cpy[3] == '\0'))) {
 102                                 while ((path_res > path_resolved) && (*--path_res != '/'));
 103
 104                                 path_cpy += 3;
 105                                 continue;
 106                         }
 107                 }
 108
 109 next:
 110                 *path_res++ = *path_cpy++;
 111         }
 112
 113         /* remove trailing slash if not root / */
 114         if ((path_res > (path_resolved+1)) && (path_res[-1] == '/'))
 115                 path_res--;
 116         else if (path_res == path_resolved)
 117                 *path_res++ = '/';
 118
 119         *path_res = '\0';
 120
 121         return path_resolved;
 122 }
 123
 124 /* Returns NULL on error.
 125 ** NB: improperly encoded URL should give client 400 [Bad Syntax]; returning
 126 ** NULL here causes 404 [Not Found], but that's not too unreasonable. */
 127 static struct path_info *
 128 uh_path_lookup(struct client *cl, const char *url)
 129 {
 130         static char path_phys[PATH_MAX];
 131         static char path_info[PATH_MAX];
 132         static struct path_info p;
 133
 134         const char *docroot = conf.docroot;
 135         int docroot_len = strlen(docroot);
 136         char *pathptr = NULL;
 137         bool slash;
 138
 139         int i = 0;
 140         int len;
 141         struct stat s;
 142         struct index_file *idx;
 143
 144         /* back out early if url is undefined */
 145         if (url == NULL)
 146                 return NULL;
 147
 148         memset(&p, 0, sizeof(p));
 149         path_phys[0] = 0;
 150         path_info[0] = 0;
 151
 152         strcpy(uh_buf, docroot);
 153
 154         /* separate query string from url */
 155         if ((pathptr = strchr(url, '?')) != NULL) {
 156                 p.query = pathptr[1] ? pathptr + 1 : NULL;
 157
 158                 /* urldecode component w/o query */
 159                 if (pathptr > url) {
 160                         if (uh_urldecode(&uh_buf[docroot_len],
 161                                          sizeof(uh_buf) - docroot_len - 1,
 162                                          url, pathptr - url ) < 0)
 163                                 return NULL;
 164                 }
 165         }
 166
 167         /* no query string, decode all of url */
 168         else if (uh_urldecode(&uh_buf[docroot_len],
 169                               sizeof(uh_buf) - docroot_len - 1,
 170                               url, strlen(url) ) < 0)
 171                 return NULL;
 172
 173         /* create canon path */
 174         len = strlen(uh_buf);
 175         slash = len && uh_buf[len - 1] == '/';
 176         len = min(len, sizeof(path_phys) - 1);
 177
 178         for (i = len; i >= 0; i--) {
 179                 char ch = uh_buf[i];
 180                 bool exists;
 181
 182                 if (ch != 0 && ch != '/')
 183                         continue;
 184
 185                 uh_buf[i] = 0;
 186                 exists = !!canonpath(uh_buf, path_phys);
 187                 uh_buf[i] = ch;
 188
 189                 if (!exists)
 190                         continue;
 191
 192                 /* test current path */
 193                 if (stat(path_phys, &p.stat))
 194                         continue;
 195
 196                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 197                 break;
 198         }
 199
 200         /* check whether found path is within docroot */
 201         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 202             (path_phys[docroot_len] != 0 &&
 203              path_phys[docroot_len] != '/'))
 204                 return NULL;
 205
 206         /* is a regular file */
 207         if (p.stat.st_mode & S_IFREG) {
 208                 p.root = docroot;
 209                 p.phys = path_phys;
 210                 p.name = &path_phys[docroot_len];
 211                 p.info = path_info[0] ? path_info : NULL;
 212                 return &p;
 213         }
 214
 215         if (!(p.stat.st_mode & S_IFDIR))
 216                 return NULL;
 217
 218         if (path_info[0])
 219             return NULL;
 220
 221         pathptr = path_phys + strlen(path_phys);
 222
 223         /* ensure trailing slash */
 224         if (pathptr[-1] != '/') {
 225                 pathptr[0] = '/';
 226                 pathptr[1] = 0;
 227                 pathptr++;
 228         }
 229
 230         /* if requested url resolves to a directory and a trailing slash
 231            is missing in the request url, redirect the client to the same
 232            url with trailing slash appended */
 233         if (!slash) {
 234                 uh_http_header(cl, 302, "Found");
 235                 ustream_printf(cl->us, "Content-Length: 0\r\n");
 236                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 237                                 &path_phys[docroot_len],
 238                                 p.query ? "?" : "",
 239                                 p.query ? p.query : "");
 240                 uh_request_done(cl);
 241                 p.redirected = 1;
 242                 return &p;
 243         }
 244
 245         /* try to locate index file */
 246         len = path_phys + sizeof(path_phys) - pathptr - 1;
 247         list_for_each_entry(idx, &index_files, list) {
 248                 if (strlen(idx->name) > len)
 249                         continue;
 250
 251                 strcpy(pathptr, idx->name);
 252                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG)) {
 253                         memcpy(&p.stat, &s, sizeof(p.stat));
 254                         break;
 255                 }
 256
 257                 *pathptr = 0;
 258         }
 259
 260         p.root = docroot;
 261         p.phys = path_phys;
 262         p.name = &path_phys[docroot_len];
 263
 264         return p.phys ? &p : NULL;
 265 }
 266
 267 static const char * uh_file_mime_lookup(const char *path)
 268 {
 269         const struct mimetype *m = &uh_mime_types[0];
 270         const char *e;
 271
 272         while (m->extn) {
 273                 e = &path[strlen(path)-1];
 274
 275                 while (e >= path) {
 276                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 277                                 return m->mime;
 278
 279                         e--;
 280                 }
 281
 282                 m++;
 283         }
 284
 285         return "application/octet-stream";
 286 }
 287
 288 static const char * uh_file_mktag(struct stat *s, char *buf, int len)
 289 {
 290         snprintf(buf, len, "\"%x-%x-%x\"",
 291                          (unsigned int) s->st_ino,
 292                          (unsigned int) s->st_size,
 293                          (unsigned int) s->st_mtime);
 294
 295         return buf;
 296 }
 297
 298 static time_t uh_file_date2unix(const char *date)
 299 {
 300         struct tm t;
 301
 302         memset(&t, 0, sizeof(t));
 303
 304         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 305                 return timegm(&t);
 306
 307         return 0;
 308 }
 309
 310 static char * uh_file_unix2date(time_t ts, char *buf, int len)
 311 {
 312         struct tm *t = gmtime(&ts);
 313
 314         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 315
 316         return buf;
 317 }
 318
 319 static char *uh_file_header(struct client *cl, int idx)
 320 {
 321         if (!cl->dispatch.file.hdr[idx])
 322                 return NULL;
 323
 324         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 325 }
 326
 327 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 328 {
 329         char buf[128];
 330
 331         if (s) {
 332                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf, sizeof(buf)));
 333                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 334                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 335         }
 336         ustream_printf(cl->us, "Date: %s\r\n",
 337                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 338 }
 339
 340 static void uh_file_response_200(struct client *cl, struct stat *s)
 341 {
 342         uh_http_header(cl, 200, "OK");
 343         return uh_file_response_ok_hdrs(cl, s);
 344 }
 345
 346 static void uh_file_response_304(struct client *cl, struct stat *s)
 347 {
 348         uh_http_header(cl, 304, "Not Modified");
 349
 350         return uh_file_response_ok_hdrs(cl, s);
 351 }
 352
 353 static void uh_file_response_412(struct client *cl)
 354 {
 355         uh_http_header(cl, 412, "Precondition Failed");
 356 }
 357
 358 static bool uh_file_if_match(struct client *cl, struct stat *s)
 359 {
 360         char buf[128];
 361         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 362         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 363         char *p;
 364         int i;
 365
 366         if (!hdr)
 367                 return true;
 368
 369         p = &hdr[0];
 370         for (i = 0; i < strlen(hdr); i++)
 371         {
 372                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 373                         hdr[i++] = 0;
 374                         p = &hdr[i];
 375                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 376                         return true;
 377                 }
 378         }
 379
 380         uh_file_response_412(cl);
 381         return false;
 382 }
 383
 384 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 385 {
 386         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 387
 388         if (!hdr)
 389                 return true;
 390
 391         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 392                 uh_file_response_304(cl, s);
 393                 return false;
 394         }
 395
 396         return true;
 397 }
 398
 399 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 400 {
 401         char buf[128];
 402         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 403         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 404         char *p;
 405         int i;
 406
 407         if (!hdr)
 408                 return true;
 409
 410         p = &hdr[0];
 411         for (i = 0; i < strlen(hdr); i++) {
 412                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 413                         hdr[i++] = 0;
 414                         p = &hdr[i];
 415                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 416                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 417                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 418                                 uh_file_response_304(cl, s);
 419                         else
 420                                 uh_file_response_412(cl);
 421
 422                         return false;
 423                 }
 424         }
 425
 426         return true;
 427 }
 428
 429 static int uh_file_if_range(struct client *cl, struct stat *s)
 430 {
 431         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 432
 433         if (hdr) {
 434                 uh_file_response_412(cl);
 435                 return false;
 436         }
 437
 438         return true;
 439 }
 440
 441 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 442 {
 443         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 444
 445         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 446                 uh_file_response_412(cl);
 447                 return false;
 448         }
 449
 450         return true;
 451 }
 452
 453 static int dirent_cmp(const struct dirent **a, const struct dirent **b)
 454 {
 455         bool dir_a = !!((*a)->d_type & DT_DIR);
 456         bool dir_b = !!((*b)->d_type & DT_DIR);
 457
 458         /* directories first */
 459         if (dir_a != dir_b)
 460                 return dir_b - dir_a;
 461
 462         return alphasort(a, b);
 463 }
 464
 465 static void list_entries(struct client *cl, struct dirent **files, int count,
 466                          const char *path, char *local_path)
 467 {
 468         const char *suffix = "/";
 469         const char *type = "directory";
 470         unsigned int mode = S_IXOTH;
 471         struct stat s;
 472         char *file;
 473         char buf[128];
 474         int i;
 475
 476         file = local_path + strlen(local_path);
 477         for (i = 0; i < count; i++) {
 478                 const char *name = files[i]->d_name;
 479                 bool dir = !!(files[i]->d_type & DT_DIR);
 480
 481                 if (name[0] == '.' && name[1] == 0)
 482                         continue;
 483
 484                 sprintf(file, "%s", name);
 485                 if (stat(local_path, &s))
 486                         continue;
 487
 488                 if (!dir) {
 489                         suffix = "";
 490                         mode = S_IROTH;
 491                         type = uh_file_mime_lookup(local_path);
 492                 }
 493
 494                 if (!(s.st_mode & mode))
 495                         continue;
 496
 497                 uh_chunk_printf(cl,
 498                                 "<li><strong><a href='%s%s%s'>%s</a>%s"
 499                                 "</strong><br /><small>modified: %s"
 500                                 "<br />%s - %.02f kbyte<br />"
 501                                 "<br /></small></li>",
 502                                 path, name, suffix,
 503                                 name, suffix,
 504                                 uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 505                                 type, s.st_size / 1024.0);
 506
 507                 *file = 0;
 508                 free(files[i]);
 509         }
 510 }
 511
 512 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 513 {
 514         struct dirent **files = NULL;
 515         int count = 0;
 516
 517         uh_file_response_200(cl, NULL);
 518         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 519
 520         uh_chunk_printf(cl,
 521                 "<html><head><title>Index of %s</title></head>"
 522                 "<body><h1>Index of %s</h1><hr /><ol>",
 523                 pi->name, pi->name);
 524
 525         count = scandir(pi->phys, &files, NULL, dirent_cmp);
 526         if (count > 0) {
 527                 strcpy(uh_buf, pi->phys);
 528                 list_entries(cl, files, count, pi->name, uh_buf);
 529         }
 530         free(files);
 531
 532         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 533         uh_request_done(cl);
 534 }
 535
 536 static void file_write_cb(struct client *cl)
 537 {
 538         int fd = cl->dispatch.file.fd;
 539         int r;
 540
 541         while (cl->us->w.data_bytes < 256) {
 542                 r = read(fd, uh_buf, sizeof(uh_buf));
 543                 if (r < 0) {
 544                         if (errno == EINTR)
 545                                 continue;
 546                 }
 547
 548                 if (!r) {
 549                         uh_request_done(cl);
 550                         return;
 551                 }
 552
 553                 uh_chunk_write(cl, uh_buf, r);
 554         }
 555 }
 556
 557 static void uh_file_free(struct client *cl)
 558 {
 559         close(cl->dispatch.file.fd);
 560 }
 561
 562 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 563 {
 564         /* test preconditions */
 565         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 566                 !uh_file_if_match(cl, &pi->stat) ||
 567                 !uh_file_if_range(cl, &pi->stat) ||
 568                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 569                 !uh_file_if_none_match(cl, &pi->stat)) {
 570                 ustream_printf(cl->us, "Content-Length: 0\r\n");
 571                 ustream_printf(cl->us, "\r\n");
 572                 uh_request_done(cl);
 573                 close(fd);
 574                 return;
 575         }
 576
 577         /* write status */
 578         uh_file_response_200(cl, &pi->stat);
 579
 580         ustream_printf(cl->us, "Content-Type: %s\r\n",
 581                            uh_file_mime_lookup(pi->name));
 582
 583         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 584                            pi->stat.st_size);
 585
 586
 587         /* send body */
 588         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 589                 uh_request_done(cl);
 590                 close(fd);
 591                 return;
 592         }
 593
 594         cl->dispatch.file.fd = fd;
 595         cl->dispatch.write_cb = file_write_cb;
 596         cl->dispatch.free = uh_file_free;
 597         cl->dispatch.close_fds = uh_file_free;
 598         file_write_cb(cl);
 599 }
 600
 601 static void uh_file_request(struct client *cl, const char *url,
 602                             struct path_info *pi, struct blob_attr **tb)
 603 {
 604         int fd;
 605
 606         if (!(pi->stat.st_mode & S_IROTH))
 607                 goto error;
 608
 609         if (pi->stat.st_mode & S_IFREG) {
 610                 fd = open(pi->phys, O_RDONLY);
 611                 if (fd < 0)
 612                         goto error;
 613
 614                 cl->dispatch.file.hdr = tb;
 615                 uh_file_data(cl, pi, fd);
 616                 cl->dispatch.file.hdr = NULL;
 617                 return;
 618         }
 619
 620         if ((pi->stat.st_mode & S_IFDIR)) {
 621                 if (conf.no_dirlists)
 622                         goto error;
 623
 624                 uh_file_dirlist(cl, pi);
 625                 return;
 626         }
 627
 628 error:
 629         uh_client_error(cl, 403, "Forbidden",
 630                         "You don't have permission to access %s on this server.",
 631                         url);
 632 }
 633
 634 void uh_dispatch_add(struct dispatch_handler *d)
 635 {
 636         list_add_tail(&d->list, &dispatch_handlers);
 637 }
 638
 639 static struct dispatch_handler *
 640 dispatch_find(const char *url, struct path_info *pi)
 641 {
 642         struct dispatch_handler *d;
 643
 644         list_for_each_entry(d, &dispatch_handlers, list) {
 645                 if (pi) {
 646                         if (d->check_url)
 647                                 continue;
 648
 649                         if (d->check_path(pi, url))
 650                                 return d;
 651                 } else {
 652                         if (d->check_path)
 653                                 continue;
 654
 655                         if (d->check_url(url))
 656                                 return d;
 657                 }
 658         }
 659
 660         return NULL;
 661 }
 662
 663 static void
 664 uh_invoke_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
 665 {
 666         char *url = blobmsg_data(blob_data(cl->hdr.head));
 667
 668         n_requests++;
 669         d->handle_request(cl, url, pi);
 670 }
 671
 672 static void uh_complete_request(struct client *cl)
 673 {
 674         struct deferred_request *dr;
 675
 676         n_requests--;
 677
 678         while (!list_empty(&pending_requests)) {
 679                 if (n_requests >= conf.max_script_requests)
 680                         return;
 681
 682                 dr = list_first_entry(&pending_requests, struct deferred_request, list);
 683                 list_del(&dr->list);
 684
 685                 dr->called = true;
 686                 uh_invoke_script(dr->cl, dr->d, dr->path ? &dr->pi : NULL);
 687         }
 688 }
 689
 690
 691 static void
 692 uh_free_pending_request(struct client *cl)
 693 {
 694         struct deferred_request *dr = cl->dispatch.req_data;
 695
 696         if (dr->called)
 697                 uh_complete_request(cl);
 698         else
 699                 list_del(&dr->list);
 700         free(dr);
 701 }
 702
 703 static int field_len(const char *ptr)
 704 {
 705         if (!ptr)
 706                 return 0;
 707
 708         return strlen(ptr) + 1;
 709 }
 710
 711 #define path_info_fields \
 712         _field(root) \
 713         _field(phys) \
 714         _field(name) \
 715         _field(info) \
 716         _field(query) \
 717         _field(auth)
 718
 719 static void
 720 uh_defer_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
 721 {
 722         struct deferred_request *dr;
 723         char *_root, *_phys, *_name, *_info, *_query, *_auth;
 724
 725         cl->dispatch.req_free = uh_free_pending_request;
 726
 727         if (pi) {
 728                 /* allocate enough memory to duplicate all path_info strings in one block */
 729 #undef _field
 730 #define _field(_name) &_##_name, field_len(pi->_name),
 731                 dr = calloc_a(sizeof(*dr), path_info_fields NULL);
 732
 733                 memcpy(&dr->pi, pi, sizeof(*pi));
 734                 dr->path = true;
 735
 736                 /* copy all path_info strings */
 737 #undef _field
 738 #define _field(_name) if (pi->_name) dr->pi._name = strcpy(_##_name, pi->_name);
 739                 path_info_fields
 740         } else {
 741                 dr = calloc(1, sizeof(*dr));
 742         }
 743
 744         cl->dispatch.req_data = dr;
 745         dr->cl = cl;
 746         dr->d = d;
 747         list_add(&dr->list, &pending_requests);
 748 }
 749
 750 static void
 751 uh_invoke_handler(struct client *cl, struct dispatch_handler *d, char *url, struct path_info *pi)
 752 {
 753         if (!d->script)
 754                 return d->handle_request(cl, url, pi);
 755
 756         if (n_requests >= conf.max_script_requests)
 757                 return uh_defer_script(cl, d, pi);
 758
 759         cl->dispatch.req_free = uh_complete_request;
 760         uh_invoke_script(cl, d, pi);
 761 }
 762
 763 static bool __handle_file_request(struct client *cl, char *url)
 764 {
 765         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 766                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 767                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 768                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 769                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 770                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 771                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 772         };
 773         struct dispatch_handler *d;
 774         struct blob_attr *tb[__HDR_MAX];
 775         struct path_info *pi;
 776
 777         pi = uh_path_lookup(cl, url);
 778         if (!pi)
 779                 return false;
 780
 781         if (pi->redirected)
 782                 return true;
 783
 784         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 785         if (tb[HDR_AUTHORIZATION])
 786                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 787
 788         if (!uh_auth_check(cl, pi))
 789                 return true;
 790
 791         d = dispatch_find(url, pi);
 792         if (d)
 793                 uh_invoke_handler(cl, d, url, pi);
 794         else
 795                 uh_file_request(cl, url, pi, tb);
 796
 797         return true;
 798 }
 799
 800 void uh_handle_request(struct client *cl)
 801 {
 802         struct http_request *req = &cl->request;
 803         struct dispatch_handler *d;
 804         char *url = blobmsg_data(blob_data(cl->hdr.head));
 805         char *error_handler;
 806
 807         req->redirect_status = 200;
 808         d = dispatch_find(url, NULL);
 809         if (d)
 810                 return uh_invoke_handler(cl, d, url, NULL);
 811
 812         if (__handle_file_request(cl, url))
 813                 return;
 814
 815         req->redirect_status = 404;
 816         if (conf.error_handler) {
 817                 error_handler = alloca(strlen(conf.error_handler) + 1);
 818                 strcpy(error_handler, conf.error_handler);
 819                 if (__handle_file_request(cl, error_handler))
 820                         return;
 821         }
 822
 823         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", url);
 824 }