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 _DEFAULT_SOURCE
  21 #define _BSD_SOURCE
  22 #define _DARWIN_C_SOURCE
  23 #define _XOPEN_SOURCE 700
  24
  25 #include <sys/types.h>
  26 #include <sys/dir.h>
  27 #include <time.h>
  28 #include <strings.h>
  29 #include <dirent.h>
  30 #include <inttypes.h>
  31
  32 #include <libubox/blobmsg.h>
  33
  34 #include "uhttpd.h"
  35 #include "mimetypes.h"
  36
  37 #define MAX(a, b)       (((a) > (b)) ? (a) : (b))
  38
  39 static LIST_HEAD(index_files);
  40 static LIST_HEAD(dispatch_handlers);
  41 static LIST_HEAD(pending_requests);
  42 static int n_requests;
  43
  44 struct deferred_request {
  45         struct list_head list;
  46         struct dispatch_handler *d;
  47         struct client *cl;
  48         struct path_info pi;
  49         bool called, path;
  50 };
  51
  52 struct index_file {
  53         struct list_head list;
  54         const char *name;
  55 };
  56
  57 enum file_hdr {
  58         HDR_AUTHORIZATION,
  59         HDR_IF_MODIFIED_SINCE,
  60         HDR_IF_UNMODIFIED_SINCE,
  61         HDR_IF_MATCH,
  62         HDR_IF_NONE_MATCH,
  63         HDR_IF_RANGE,
  64         __HDR_MAX
  65 };
  66
  67 void uh_index_add(const char *filename)
  68 {
  69         struct index_file *idx;
  70
  71         idx = calloc(1, sizeof(*idx));
  72         idx->name = filename;
  73         list_add_tail(&idx->list, &index_files);
  74 }
  75
  76 static char * canonpath(const char *path, char *path_resolved)
  77 {
  78         const char *path_cpy = path;
  79         char *path_res = path_resolved;
  80
  81         if (conf.no_symlinks)
  82                 return realpath(path, path_resolved);
  83
  84         /* normalize */
  85         while ((*path_cpy != '\0') && (path_cpy < (path + PATH_MAX - 2))) {
  86                 if (*path_cpy != '/')
  87                         goto next;
  88
  89                 /* skip repeating / */
  90                 if (path_cpy[1] == '/') {
  91                         path_cpy++;
  92                         continue;
  93                 }
  94
  95                 /* /./ or /../ */
  96                 if (path_cpy[1] == '.') {
  97                         /* skip /./ */
  98                         if ((path_cpy[2] == '/') || (path_cpy[2] == '\0')) {
  99                                 path_cpy += 2;
 100                                 continue;
 101                         }
 102
 103                         /* collapse /x/../ */
 104                         if ((path_cpy[2] == '.') &&
 105                             ((path_cpy[3] == '/') || (path_cpy[3] == '\0'))) {
 106                                 while ((path_res > path_resolved) && (*--path_res != '/'));
 107
 108                                 path_cpy += 3;
 109                                 continue;
 110                         }
 111                 }
 112
 113 next:
 114                 *path_res++ = *path_cpy++;
 115         }
 116
 117         /* remove trailing slash if not root / */
 118         if ((path_res > (path_resolved+1)) && (path_res[-1] == '/'))
 119                 path_res--;
 120         else if (path_res == path_resolved)
 121                 *path_res++ = '/';
 122
 123         *path_res = '\0';
 124
 125         return path_resolved;
 126 }
 127
 128 /* Returns NULL on error.
 129 ** NB: improperly encoded URL should give client 400 [Bad Syntax]; returning
 130 ** NULL here causes 404 [Not Found], but that's not too unreasonable. */
 131 struct path_info *
 132 uh_path_lookup(struct client *cl, const char *url)
 133 {
 134         static char path_phys[PATH_MAX];
 135         static char path_info[PATH_MAX];
 136         static char path_query[PATH_MAX];
 137         static struct path_info p;
 138
 139         const char *docroot = conf.docroot;
 140         int docroot_len = strlen(docroot);
 141         char *pathptr = NULL;
 142         bool slash;
 143
 144         int i = 0;
 145         int len;
 146         struct stat s;
 147         struct index_file *idx;
 148
 149         /* back out early if url is undefined */
 150         if (url == NULL)
 151                 return NULL;
 152
 153         memset(&p, 0, sizeof(p));
 154         path_phys[0] = 0;
 155         path_info[0] = 0;
 156
 157         strcpy(uh_buf, docroot);
 158
 159         /* separate query string from url */
 160         if ((pathptr = strchr(url, '?')) != NULL) {
 161                 if (pathptr[1]) {
 162                         p.query = path_query;
 163                         snprintf(path_query, sizeof(path_query), "%s",
 164                                  pathptr + 1);
 165                 }
 166
 167                 /* urldecode component w/o query */
 168                 if (pathptr > url) {
 169                         if (uh_urldecode(&uh_buf[docroot_len],
 170                                          sizeof(uh_buf) - docroot_len - 1,
 171                                          url, pathptr - url ) < 0)
 172                                 return NULL;
 173                 }
 174         }
 175
 176         /* no query string, decode all of url */
 177         else if (uh_urldecode(&uh_buf[docroot_len],
 178                               sizeof(uh_buf) - docroot_len - 1,
 179                               url, strlen(url) ) < 0)
 180                 return NULL;
 181
 182         /* create canon path */
 183         len = strlen(uh_buf);
 184         slash = len && uh_buf[len - 1] == '/';
 185         len = min(len, sizeof(path_phys) - 1);
 186
 187         for (i = len; i >= 0; i--) {
 188                 char ch = uh_buf[i];
 189                 bool exists;
 190
 191                 if (ch != 0 && ch != '/')
 192                         continue;
 193
 194                 uh_buf[i] = 0;
 195                 exists = !!canonpath(uh_buf, path_phys);
 196                 uh_buf[i] = ch;
 197
 198                 if (!exists)
 199                         continue;
 200
 201                 /* test current path */
 202                 if (stat(path_phys, &p.stat))
 203                         continue;
 204
 205                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 206                 break;
 207         }
 208
 209         /* check whether found path is within docroot */
 210         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 211             (path_phys[docroot_len] != 0 &&
 212              path_phys[docroot_len] != '/'))
 213                 return NULL;
 214
 215         /* is a regular file */
 216         if (p.stat.st_mode & S_IFREG) {
 217                 p.root = docroot;
 218                 p.phys = path_phys;
 219                 p.name = &path_phys[docroot_len];
 220                 p.info = path_info[0] ? path_info : NULL;
 221                 return &p;
 222         }
 223
 224         if (!(p.stat.st_mode & S_IFDIR))
 225                 return NULL;
 226
 227         if (path_info[0])
 228             return NULL;
 229
 230         pathptr = path_phys + strlen(path_phys);
 231
 232         /* ensure trailing slash */
 233         if (pathptr[-1] != '/') {
 234                 pathptr[0] = '/';
 235                 pathptr[1] = 0;
 236                 pathptr++;
 237         }
 238
 239         /* if requested url resolves to a directory and a trailing slash
 240            is missing in the request url, redirect the client to the same
 241            url with trailing slash appended */
 242         if (!slash) {
 243                 uh_http_header(cl, 302, "Found");
 244                 if (!uh_use_chunked(cl))
 245                         ustream_printf(cl->us, "Content-Length: 0\r\n");
 246                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 247                                 &path_phys[docroot_len],
 248                                 p.query ? "?" : "",
 249                                 p.query ? p.query : "");
 250                 uh_request_done(cl);
 251                 p.redirected = 1;
 252                 return &p;
 253         }
 254
 255         /* try to locate index file */
 256         len = path_phys + sizeof(path_phys) - pathptr - 1;
 257         list_for_each_entry(idx, &index_files, list) {
 258                 if (strlen(idx->name) > len)
 259                         continue;
 260
 261                 strcpy(pathptr, idx->name);
 262                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG)) {
 263                         memcpy(&p.stat, &s, sizeof(p.stat));
 264                         break;
 265                 }
 266
 267                 *pathptr = 0;
 268         }
 269
 270         p.root = docroot;
 271         p.phys = path_phys;
 272         p.name = &path_phys[docroot_len];
 273
 274         return p.phys ? &p : NULL;
 275 }
 276
 277 static const char * uh_file_mime_lookup(const char *path)
 278 {
 279         const struct mimetype *m = &uh_mime_types[0];
 280         const char *e;
 281
 282         while (m->extn) {
 283                 e = &path[strlen(path)-1];
 284
 285                 while (e >= path) {
 286                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 287                                 return m->mime;
 288
 289                         e--;
 290                 }
 291
 292                 m++;
 293         }
 294
 295         return "application/octet-stream";
 296 }
 297
 298 static const char * uh_file_mktag(struct stat *s, char *buf, int len)
 299 {
 300         snprintf(buf, len, "\"%" PRIx64 "-%" PRIx64 "-%" PRIx64 "\"",
 301                  s->st_ino, s->st_size, (uint64_t)s->st_mtime);
 302
 303         return buf;
 304 }
 305
 306 static time_t uh_file_date2unix(const char *date)
 307 {
 308         struct tm t;
 309
 310         memset(&t, 0, sizeof(t));
 311
 312         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 313                 return timegm(&t);
 314
 315         return 0;
 316 }
 317
 318 static char * uh_file_unix2date(time_t ts, char *buf, int len)
 319 {
 320         struct tm *t = gmtime(&ts);
 321
 322         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 323
 324         return buf;
 325 }
 326
 327 static char *uh_file_header(struct client *cl, int idx)
 328 {
 329         if (!cl->dispatch.file.hdr[idx])
 330                 return NULL;
 331
 332         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 333 }
 334
 335 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 336 {
 337         char buf[128];
 338
 339         if (s) {
 340                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf, sizeof(buf)));
 341                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 342                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 343         }
 344         ustream_printf(cl->us, "Date: %s\r\n",
 345                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 346 }
 347
 348 static void uh_file_response_200(struct client *cl, struct stat *s)
 349 {
 350         uh_http_header(cl, 200, "OK");
 351         return uh_file_response_ok_hdrs(cl, s);
 352 }
 353
 354 static void uh_file_response_304(struct client *cl, struct stat *s)
 355 {
 356         uh_http_header(cl, 304, "Not Modified");
 357
 358         return uh_file_response_ok_hdrs(cl, s);
 359 }
 360
 361 static void uh_file_response_405(struct client *cl)
 362 {
 363         uh_http_header(cl, 405, "Method Not Allowed");
 364 }
 365
 366 static void uh_file_response_412(struct client *cl)
 367 {
 368         uh_http_header(cl, 412, "Precondition Failed");
 369 }
 370
 371 static bool uh_file_if_match(struct client *cl, struct stat *s)
 372 {
 373         char buf[128];
 374         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 375         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 376         char *p;
 377         int i;
 378
 379         if (!hdr)
 380                 return true;
 381
 382         p = &hdr[0];
 383         for (i = 0; i < strlen(hdr); i++)
 384         {
 385                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 386                         hdr[i++] = 0;
 387                         p = &hdr[i];
 388                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 389                         return true;
 390                 }
 391         }
 392
 393         uh_file_response_412(cl);
 394         return false;
 395 }
 396
 397 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 398 {
 399         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 400
 401         if (!hdr)
 402                 return true;
 403
 404         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 405                 uh_file_response_304(cl, s);
 406                 return false;
 407         }
 408
 409         return true;
 410 }
 411
 412 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 413 {
 414         char buf[128];
 415         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 416         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 417         char *p;
 418         int i;
 419
 420         if (!hdr)
 421                 return true;
 422
 423         p = &hdr[0];
 424         for (i = 0; i < strlen(hdr); i++) {
 425                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 426                         hdr[i++] = 0;
 427                         p = &hdr[i];
 428                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 429                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 430                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 431                                 uh_file_response_304(cl, s);
 432                         else
 433                                 uh_file_response_412(cl);
 434
 435                         return false;
 436                 }
 437         }
 438
 439         return true;
 440 }
 441
 442 static int uh_file_if_range(struct client *cl, struct stat *s)
 443 {
 444         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 445
 446         if (hdr) {
 447                 uh_file_response_412(cl);
 448                 return false;
 449         }
 450
 451         return true;
 452 }
 453
 454 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 455 {
 456         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 457
 458         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 459                 uh_file_response_412(cl);
 460                 return false;
 461         }
 462
 463         return true;
 464 }
 465
 466 static int dirent_cmp(const struct dirent **a, const struct dirent **b)
 467 {
 468         bool dir_a = !!((*a)->d_type & DT_DIR);
 469         bool dir_b = !!((*b)->d_type & DT_DIR);
 470
 471         /* directories first */
 472         if (dir_a != dir_b)
 473                 return dir_b - dir_a;
 474
 475         return alphasort(a, b);
 476 }
 477
 478 static void list_entries(struct client *cl, struct dirent **files, int count,
 479                          const char *path, char *local_path)
 480 {
 481         const char *suffix = "/";
 482         const char *type = "directory";
 483         unsigned int mode = S_IXOTH;
 484         struct stat s;
 485         char *escaped;
 486         char *file;
 487         char buf[128];
 488         int i;
 489
 490         file = local_path + strlen(local_path);
 491         for (i = 0; i < count; i++) {
 492                 const char *name = files[i]->d_name;
 493                 bool dir = !!(files[i]->d_type & DT_DIR);
 494
 495                 if (name[0] == '.' && name[1] == 0)
 496                         goto next;
 497
 498                 sprintf(file, "%s", name);
 499                 if (stat(local_path, &s))
 500                         goto next;
 501
 502                 if (!dir) {
 503                         suffix = "";
 504                         mode = S_IROTH;
 505                         type = uh_file_mime_lookup(local_path);
 506                 }
 507
 508                 if (!(s.st_mode & mode))
 509                         goto next;
 510
 511                 escaped = uh_htmlescape(name);
 512
 513                 if (!escaped)
 514                         goto next;
 515
 516                 uh_chunk_printf(cl,
 517                                 "<li><strong><a href='%s%s%s'>%s</a>%s"
 518                                 "</strong><br /><small>modified: %s"
 519                                 "<br />%s - %.02f kbyte<br />"
 520                                 "<br /></small></li>",
 521                                 path, escaped, suffix,
 522                                 escaped, suffix,
 523                                 uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 524                                 type, s.st_size / 1024.0);
 525
 526                 free(escaped);
 527                 *file = 0;
 528 next:
 529                 free(files[i]);
 530         }
 531 }
 532
 533 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 534 {
 535         struct dirent **files = NULL;
 536         char *escaped_path = uh_htmlescape(pi->name);
 537         int count = 0;
 538
 539         if (!escaped_path)
 540         {
 541                 uh_client_error(cl, 500, "Internal Server Error", "Out of memory");
 542                 return;
 543         }
 544
 545         uh_file_response_200(cl, NULL);
 546         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 547
 548         uh_chunk_printf(cl,
 549                 "<html><head><title>Index of %s</title></head>"
 550                 "<body><h1>Index of %s</h1><hr /><ol>",
 551                 escaped_path, escaped_path);
 552
 553         count = scandir(pi->phys, &files, NULL, dirent_cmp);
 554         if (count > 0) {
 555                 strcpy(uh_buf, pi->phys);
 556                 list_entries(cl, files, count, escaped_path, uh_buf);
 557         }
 558         free(escaped_path);
 559         free(files);
 560
 561         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 562         uh_request_done(cl);
 563 }
 564
 565 static void file_write_cb(struct client *cl)
 566 {
 567         int fd = cl->dispatch.file.fd;
 568         int r;
 569
 570         while (cl->us->w.data_bytes < 256) {
 571                 r = read(fd, uh_buf, sizeof(uh_buf));
 572                 if (r < 0) {
 573                         if (errno == EINTR)
 574                                 continue;
 575                 }
 576
 577                 if (!r) {
 578                         uh_request_done(cl);
 579                         return;
 580                 }
 581
 582                 uh_chunk_write(cl, uh_buf, r);
 583         }
 584 }
 585
 586 static void uh_file_free(struct client *cl)
 587 {
 588         close(cl->dispatch.file.fd);
 589 }
 590
 591 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 592 {
 593         /* test preconditions */
 594         if (!cl->dispatch.no_cache &&
 595             (!uh_file_if_modified_since(cl, &pi->stat) ||
 596              !uh_file_if_match(cl, &pi->stat) ||
 597              !uh_file_if_range(cl, &pi->stat) ||
 598              !uh_file_if_unmodified_since(cl, &pi->stat) ||
 599              !uh_file_if_none_match(cl, &pi->stat))) {
 600                 ustream_printf(cl->us, "\r\n");
 601                 uh_request_done(cl);
 602                 close(fd);
 603                 return;
 604         }
 605
 606         /* write status */
 607         uh_file_response_200(cl, &pi->stat);
 608
 609         ustream_printf(cl->us, "Content-Type: %s\r\n",
 610                            uh_file_mime_lookup(pi->name));
 611
 612         ustream_printf(cl->us, "Content-Length: %" PRIu64 "\r\n\r\n",
 613                            pi->stat.st_size);
 614
 615
 616         /* send body */
 617         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 618                 uh_request_done(cl);
 619                 close(fd);
 620                 return;
 621         }
 622
 623         cl->dispatch.file.fd = fd;
 624         cl->dispatch.write_cb = file_write_cb;
 625         cl->dispatch.free = uh_file_free;
 626         cl->dispatch.close_fds = uh_file_free;
 627         file_write_cb(cl);
 628 }
 629
 630 static bool __handle_file_request(struct client *cl, char *url);
 631
 632 static void uh_file_request(struct client *cl, const char *url,
 633                             struct path_info *pi, struct blob_attr **tb)
 634 {
 635         int fd;
 636         struct http_request *req = &cl->request;
 637         char *error_handler, *escaped_url;
 638
 639         switch (cl->request.method) {
 640         case UH_HTTP_MSG_GET:
 641         case UH_HTTP_MSG_POST:
 642         case UH_HTTP_MSG_HEAD:
 643         case UH_HTTP_MSG_OPTIONS:
 644                 break;
 645
 646         default:
 647                 uh_file_response_405(cl);
 648                 ustream_printf(cl->us, "\r\n");
 649                 uh_request_done(cl);
 650                 return;
 651         }
 652
 653         if (!(pi->stat.st_mode & S_IROTH))
 654                 goto error;
 655
 656         if (pi->stat.st_mode & S_IFREG) {
 657                 fd = open(pi->phys, O_RDONLY);
 658                 if (fd < 0)
 659                         goto error;
 660
 661                 req->disable_chunked = true;
 662                 cl->dispatch.file.hdr = tb;
 663                 uh_file_data(cl, pi, fd);
 664                 cl->dispatch.file.hdr = NULL;
 665                 return;
 666         }
 667
 668         if ((pi->stat.st_mode & S_IFDIR)) {
 669                 if (conf.no_dirlists)
 670                         goto error;
 671
 672                 uh_file_dirlist(cl, pi);
 673                 return;
 674         }
 675
 676 error:
 677         /* check for a previously set 403 redirect status to prevent infinite
 678            recursion when the error page itself lacks sufficient permissions */
 679         if (conf.error_handler && req->redirect_status != 403) {
 680                 req->redirect_status = 403;
 681                 error_handler = alloca(strlen(conf.error_handler) + 1);
 682                 strcpy(error_handler, conf.error_handler);
 683                 if (__handle_file_request(cl, error_handler))
 684                         return;
 685         }
 686
 687         escaped_url = uh_htmlescape(url);
 688
 689         uh_client_error(cl, 403, "Forbidden",
 690                         "You don't have permission to access %s on this server.",
 691                         escaped_url ? escaped_url : "the url");
 692
 693         if (escaped_url)
 694                 free(escaped_url);
 695 }
 696
 697 void uh_dispatch_add(struct dispatch_handler *d)
 698 {
 699         list_add_tail(&d->list, &dispatch_handlers);
 700 }
 701
 702 static struct dispatch_handler *
 703 dispatch_find(const char *url, struct path_info *pi)
 704 {
 705         struct dispatch_handler *d;
 706
 707         list_for_each_entry(d, &dispatch_handlers, list) {
 708                 if (pi) {
 709                         if (d->check_url)
 710                                 continue;
 711
 712                         if (d->check_path(pi, url))
 713                                 return d;
 714                 } else {
 715                         if (d->check_path)
 716                                 continue;
 717
 718                         if (d->check_url(url))
 719                                 return d;
 720                 }
 721         }
 722
 723         return NULL;
 724 }
 725
 726 static void
 727 uh_invoke_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
 728 {
 729         char *url = blobmsg_data(blob_data(cl->hdr.head));
 730
 731         n_requests++;
 732         d->handle_request(cl, url, pi);
 733 }
 734
 735 static void uh_complete_request(struct client *cl)
 736 {
 737         struct deferred_request *dr;
 738
 739         n_requests--;
 740
 741         while (!list_empty(&pending_requests)) {
 742                 if (n_requests >= conf.max_script_requests)
 743                         return;
 744
 745                 dr = list_first_entry(&pending_requests, struct deferred_request, list);
 746                 list_del(&dr->list);
 747
 748                 cl = dr->cl;
 749                 dr->called = true;
 750                 cl->dispatch.data_blocked = false;
 751                 uh_invoke_script(cl, dr->d, dr->path ? &dr->pi : NULL);
 752                 client_poll_post_data(cl);
 753         }
 754 }
 755
 756
 757 static void
 758 uh_free_pending_request(struct client *cl)
 759 {
 760         struct deferred_request *dr = cl->dispatch.req_data;
 761
 762         if (dr->called)
 763                 uh_complete_request(cl);
 764         else
 765                 list_del(&dr->list);
 766         free(dr);
 767 }
 768
 769 static int field_len(const char *ptr)
 770 {
 771         if (!ptr)
 772                 return 0;
 773
 774         return strlen(ptr) + 1;
 775 }
 776
 777 #define path_info_fields \
 778         _field(root) \
 779         _field(phys) \
 780         _field(name) \
 781         _field(info) \
 782         _field(query)
 783
 784 static void
 785 uh_defer_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
 786 {
 787         struct deferred_request *dr;
 788         char *_root, *_phys, *_name, *_info, *_query;
 789
 790         cl->dispatch.req_free = uh_free_pending_request;
 791
 792         if (pi) {
 793                 /* allocate enough memory to duplicate all path_info strings in one block */
 794 #undef _field
 795 #define _field(_name) &_##_name, field_len(pi->_name),
 796                 dr = calloc_a(sizeof(*dr), path_info_fields NULL);
 797
 798                 memcpy(&dr->pi, pi, sizeof(*pi));
 799                 dr->path = true;
 800
 801                 /* copy all path_info strings */
 802 #undef _field
 803 #define _field(_name) if (pi->_name) dr->pi._name = strcpy(_##_name, pi->_name);
 804                 path_info_fields
 805         } else {
 806                 dr = calloc(1, sizeof(*dr));
 807         }
 808
 809         cl->dispatch.req_data = dr;
 810         cl->dispatch.data_blocked = true;
 811         dr->cl = cl;
 812         dr->d = d;
 813         list_add(&dr->list, &pending_requests);
 814 }
 815
 816 static void
 817 uh_invoke_handler(struct client *cl, struct dispatch_handler *d, char *url, struct path_info *pi)
 818 {
 819         if (!d->script)
 820                 return d->handle_request(cl, url, pi);
 821
 822         if (n_requests >= conf.max_script_requests)
 823                 return uh_defer_script(cl, d, pi);
 824
 825         cl->dispatch.req_free = uh_complete_request;
 826         uh_invoke_script(cl, d, pi);
 827 }
 828
 829 static bool __handle_file_request(struct client *cl, char *url)
 830 {
 831         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 832                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 833                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 834                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 835                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 836                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 837                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 838         };
 839         struct dispatch_handler *d;
 840         struct blob_attr *tb[__HDR_MAX];
 841         struct path_info *pi;
 842         char *user, *pass, *auth;
 843
 844         pi = uh_path_lookup(cl, url);
 845         if (!pi)
 846                 return false;
 847
 848         if (pi->redirected)
 849                 return true;
 850
 851         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 852
 853         auth = tb[HDR_AUTHORIZATION] ? blobmsg_data(tb[HDR_AUTHORIZATION]) : NULL;
 854
 855         if (!uh_auth_check(cl, pi->name, auth, &user, &pass))
 856                 return true;
 857
 858         if (user && pass) {
 859                 blobmsg_add_string(&cl->hdr, "http-auth-user", user);
 860                 blobmsg_add_string(&cl->hdr, "http-auth-pass", pass);
 861         }
 862
 863         d = dispatch_find(url, pi);
 864         if (d)
 865                 uh_invoke_handler(cl, d, url, pi);
 866         else
 867                 uh_file_request(cl, url, pi, tb);
 868
 869         return true;
 870 }
 871
 872 static char *uh_handle_alias(char *old_url)
 873 {
 874         struct alias *alias;
 875         static char *new_url;
 876         static int url_len;
 877
 878         if (!list_empty(&conf.cgi_alias)) list_for_each_entry(alias, &conf.cgi_alias, list) {
 879                 int old_len;
 880                 int new_len;
 881                 int path_len = 0;
 882
 883                 if (!uh_path_match(alias->alias, old_url))
 884                         continue;
 885
 886                 if (alias->path)
 887                         path_len = strlen(alias->path);
 888
 889                 old_len = strlen(old_url) + 1;
 890                 new_len = old_len + MAX(conf.cgi_prefix_len, path_len);
 891
 892                 if (new_len > url_len) {
 893                         new_url = realloc(new_url, new_len);
 894                         url_len = new_len;
 895                 }
 896
 897                 *new_url = '\0';
 898
 899                 if (alias->path)
 900                         strcpy(new_url, alias->path);
 901                 else if (conf.cgi_prefix)
 902                         strcpy(new_url, conf.cgi_prefix);
 903                 strcat(new_url, old_url);
 904
 905                 return new_url;
 906         }
 907         return old_url;
 908 }
 909
 910 void uh_handle_request(struct client *cl)
 911 {
 912         struct http_request *req = &cl->request;
 913         struct dispatch_handler *d;
 914         char *url = blobmsg_data(blob_data(cl->hdr.head));
 915         char *error_handler, *escaped_url;
 916
 917         blob_buf_init(&cl->hdr_response, 0);
 918         url = uh_handle_alias(url);
 919
 920         uh_handler_run(cl, &url, false);
 921         if (!url)
 922                 return;
 923
 924         req->redirect_status = 200;
 925         d = dispatch_find(url, NULL);
 926         if (d)
 927                 return uh_invoke_handler(cl, d, url, NULL);
 928
 929         if (__handle_file_request(cl, url))
 930                 return;
 931
 932         if (uh_handler_run(cl, &url, true)) {
 933                 if (!url)
 934                         return;
 935
 936                 uh_handler_run(cl, &url, false);
 937                 if (__handle_file_request(cl, url))
 938                         return;
 939         }
 940
 941         req->redirect_status = 404;
 942         if (conf.error_handler) {
 943                 error_handler = alloca(strlen(conf.error_handler) + 1);
 944                 strcpy(error_handler, conf.error_handler);
 945                 if (__handle_file_request(cl, error_handler))
 946                         return;
 947         }
 948
 949         escaped_url = uh_htmlescape(url);
 950
 951         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.",
 952                         escaped_url ? escaped_url : "");
 953
 954         if (escaped_url)
 955                 free(escaped_url);
 956 }