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