file.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2012 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License");
   8  *  you may not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS,
  15  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License.
  18  */
  19
  20 #define _BSD_SOURCE
  21 #define _XOPEN_SOURCE 700
  22
  23 #include <sys/types.h>
  24 #include <sys/dir.h>
  25 #include <time.h>
  26 #include <strings.h>
  27
  28 #include <libubox/blobmsg.h>
  29
  30 #include "uhttpd.h"
  31 #include "mimetypes.h"
  32
  33 static char _tag[128];
  34 static LIST_HEAD(index_files);
  35 static LIST_HEAD(dispatch_handlers);
  36
  37 struct index_file {
  38         struct list_head list;
  39         const char *name;
  40 };
  41
  42 enum file_hdr {
  43         HDR_IF_MODIFIED_SINCE,
  44         HDR_IF_UNMODIFIED_SINCE,
  45         HDR_IF_MATCH,
  46         HDR_IF_NONE_MATCH,
  47         HDR_IF_RANGE,
  48         __HDR_MAX
  49 };
  50
  51 void uh_index_add(const char *filename)
  52 {
  53         struct index_file *idx;
  54
  55         idx = calloc(1, sizeof(*idx));
  56         idx->name = filename;
  57         list_add_tail(&idx->list, &index_files);
  58 }
  59
  60 static char * canonpath(const char *path, char *path_resolved)
  61 {
  62         const char *path_cpy = path;
  63         char *path_res = path_resolved;
  64
  65         if (conf.no_symlinks)
  66                 return realpath(path, path_resolved);
  67
  68         /* normalize */
  69         while ((*path_cpy != '\0') && (path_cpy < (path + PATH_MAX - 2))) {
  70                 if (*path_cpy != '/')
  71                         goto next;
  72
  73                 /* skip repeating / */
  74                 if (path_cpy[1] == '/') {
  75                         path_cpy++;
  76                         continue;
  77                 }
  78
  79                 /* /./ or /../ */
  80                 if (path_cpy[1] == '.') {
  81                         /* skip /./ */
  82                         if ((path_cpy[2] == '/') || (path_cpy[2] == '\0')) {
  83                                 path_cpy += 2;
  84                                 continue;
  85                         }
  86
  87                         /* collapse /x/../ */
  88                         if ((path_cpy[2] == '.') &&
  89                             ((path_cpy[3] == '/') || (path_cpy[3] == '\0'))) {
  90                                 while ((path_res > path_resolved) && (*--path_res != '/'));
  91
  92                                 path_cpy += 3;
  93                                 continue;
  94                         }
  95                 }
  96
  97 next:
  98                 *path_res++ = *path_cpy++;
  99         }
 100
 101         /* remove trailing slash if not root / */
 102         if ((path_res > (path_resolved+1)) && (path_res[-1] == '/'))
 103                 path_res--;
 104         else if (path_res == path_resolved)
 105                 *path_res++ = '/';
 106
 107         *path_res = '\0';
 108
 109         return path_resolved;
 110 }
 111
 112 /* Returns NULL on error.
 113 ** NB: improperly encoded URL should give client 400 [Bad Syntax]; returning
 114 ** NULL here causes 404 [Not Found], but that's not too unreasonable. */
 115 static struct path_info *
 116 uh_path_lookup(struct client *cl, const char *url)
 117 {
 118         static char path_phys[PATH_MAX];
 119         static char path_info[PATH_MAX];
 120         static struct path_info p;
 121
 122         const char *docroot = conf.docroot;
 123         int docroot_len = strlen(docroot);
 124         char *pathptr = NULL;
 125         bool slash;
 126
 127         int i = 0;
 128         int len;
 129         struct stat s;
 130         struct index_file *idx;
 131
 132         /* back out early if url is undefined */
 133         if (url == NULL)
 134                 return NULL;
 135
 136         memset(&p, 0, sizeof(p));
 137         path_phys[0] = 0;
 138         path_info[0] = 0;
 139
 140         strcpy(uh_buf, docroot);
 141
 142         /* separate query string from url */
 143         if ((pathptr = strchr(url, '?')) != NULL) {
 144                 p.query = pathptr[1] ? pathptr + 1 : NULL;
 145
 146                 /* urldecode component w/o query */
 147                 if (pathptr > url) {
 148                         if (uh_urldecode(&uh_buf[docroot_len],
 149                                          sizeof(uh_buf) - docroot_len - 1,
 150                                          url, pathptr - url ) < 0)
 151                                 return NULL;
 152                 }
 153         }
 154
 155         /* no query string, decode all of url */
 156         else if (uh_urldecode(&uh_buf[docroot_len],
 157                               sizeof(uh_buf) - docroot_len - 1,
 158                               url, strlen(url) ) < 0)
 159                 return NULL;
 160
 161         /* create canon path */
 162         len = strlen(uh_buf);
 163         slash = len && uh_buf[len - 1] == '/';
 164         len = min(len, sizeof(path_phys) - 1);
 165
 166         for (i = len; i >= 0; i--) {
 167                 char ch = uh_buf[i];
 168                 bool exists;
 169
 170                 if (ch != 0 && ch != '/')
 171                         continue;
 172
 173                 uh_buf[i] = 0;
 174                 exists = !!canonpath(uh_buf, path_phys);
 175                 uh_buf[i] = ch;
 176
 177                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 178                 break;
 179         }
 180
 181         /* check whether found path is within docroot */
 182         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 183             (path_phys[docroot_len] != 0 &&
 184              path_phys[docroot_len] != '/'))
 185                 return NULL;
 186
 187         /* test current path */
 188         if (stat(path_phys, &p.stat))
 189                 return NULL;
 190
 191         /* is a regular file */
 192         if (p.stat.st_mode & S_IFREG) {
 193                 p.root = docroot;
 194                 p.phys = path_phys;
 195                 p.name = &path_phys[docroot_len];
 196                 p.info = path_info[0] ? path_info : NULL;
 197                 return &p;
 198         }
 199
 200         if (!(p.stat.st_mode & S_IFDIR))
 201                 return NULL;
 202
 203         if (path_info[0])
 204             return NULL;
 205
 206         pathptr = path_phys + strlen(path_phys);
 207
 208         /* ensure trailing slash */
 209         if (pathptr[-1] != '/') {
 210                 pathptr[0] = '/';
 211                 pathptr[1] = 0;
 212                 pathptr++;
 213         }
 214
 215         /* if requested url resolves to a directory and a trailing slash
 216            is missing in the request url, redirect the client to the same
 217            url with trailing slash appended */
 218         if (!slash) {
 219                 uh_http_header(cl, 302, "Found");
 220                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 221                                 &path_phys[docroot_len],
 222                                 p.query ? "?" : "",
 223                                 p.query ? p.query : "");
 224                 uh_request_done(cl);
 225                 p.redirected = 1;
 226                 return &p;
 227         }
 228
 229         /* try to locate index file */
 230         len = path_phys + sizeof(path_phys) - pathptr - 1;
 231         list_for_each_entry(idx, &index_files, list) {
 232                 if (strlen(idx->name) > len)
 233                         continue;
 234
 235                 strcpy(pathptr, idx->name);
 236                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG))
 237                         break;
 238
 239                 *pathptr = 0;
 240         }
 241
 242         p.root = docroot;
 243         p.phys = path_phys;
 244         p.name = &path_phys[docroot_len];
 245
 246         return p.phys ? &p : NULL;
 247 }
 248
 249 #ifdef __APPLE__
 250 time_t timegm (struct tm *tm);
 251 #endif
 252
 253 static const char * uh_file_mime_lookup(const char *path)
 254 {
 255         struct mimetype *m = &uh_mime_types[0];
 256         const char *e;
 257
 258         while (m->extn) {
 259                 e = &path[strlen(path)-1];
 260
 261                 while (e >= path) {
 262                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 263                                 return m->mime;
 264
 265                         e--;
 266                 }
 267
 268                 m++;
 269         }
 270
 271         return "application/octet-stream";
 272 }
 273
 274 static const char * uh_file_mktag(struct stat *s)
 275 {
 276         snprintf(_tag, sizeof(_tag), "\"%x-%x-%x\"",
 277                          (unsigned int) s->st_ino,
 278                          (unsigned int) s->st_size,
 279                          (unsigned int) s->st_mtime);
 280
 281         return _tag;
 282 }
 283
 284 static time_t uh_file_date2unix(const char *date)
 285 {
 286         struct tm t;
 287
 288         memset(&t, 0, sizeof(t));
 289
 290         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 291                 return timegm(&t);
 292
 293         return 0;
 294 }
 295
 296 static char * uh_file_unix2date(time_t ts)
 297 {
 298         struct tm *t = gmtime(&ts);
 299
 300         strftime(_tag, sizeof(_tag), "%a, %d %b %Y %H:%M:%S GMT", t);
 301
 302         return _tag;
 303 }
 304
 305 static char *uh_file_header(struct client *cl, int idx)
 306 {
 307         if (!cl->dispatch.file.hdr[idx])
 308                 return NULL;
 309
 310         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 311 }
 312
 313 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 314 {
 315         if (s) {
 316                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s));
 317                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 318                                uh_file_unix2date(s->st_mtime));
 319         }
 320         ustream_printf(cl->us, "Date: %s\r\n", uh_file_unix2date(time(NULL)));
 321 }
 322
 323 static void uh_file_response_200(struct client *cl, struct stat *s)
 324 {
 325         uh_http_header(cl, 200, "OK");
 326         return uh_file_response_ok_hdrs(cl, s);
 327 }
 328
 329 static void uh_file_response_304(struct client *cl, struct stat *s)
 330 {
 331         uh_http_header(cl, 304, "Not Modified");
 332
 333         return uh_file_response_ok_hdrs(cl, s);
 334 }
 335
 336 static void uh_file_response_412(struct client *cl)
 337 {
 338         uh_http_header(cl, 412, "Precondition Failed");
 339 }
 340
 341 static bool uh_file_if_match(struct client *cl, struct stat *s)
 342 {
 343         const char *tag = uh_file_mktag(s);
 344         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 345         char *p;
 346         int i;
 347
 348         if (!hdr)
 349                 return true;
 350
 351         p = &hdr[0];
 352         for (i = 0; i < strlen(hdr); i++)
 353         {
 354                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 355                         hdr[i++] = 0;
 356                         p = &hdr[i];
 357                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 358                         return true;
 359                 }
 360         }
 361
 362         uh_file_response_412(cl);
 363         return false;
 364 }
 365
 366 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 367 {
 368         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 369
 370         if (!hdr)
 371                 return true;
 372
 373         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 374                 uh_file_response_304(cl, s);
 375                 return false;
 376         }
 377
 378         return true;
 379 }
 380
 381 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 382 {
 383         const char *tag = uh_file_mktag(s);
 384         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 385         char *p;
 386         int i;
 387
 388         if (!hdr)
 389                 return true;
 390
 391         p = &hdr[0];
 392         for (i = 0; i < strlen(hdr); i++) {
 393                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 394                         hdr[i++] = 0;
 395                         p = &hdr[i];
 396                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 397                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 398                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 399                                 uh_file_response_304(cl, s);
 400                         else
 401                                 uh_file_response_412(cl);
 402
 403                         return false;
 404                 }
 405         }
 406
 407         return true;
 408 }
 409
 410 static int uh_file_if_range(struct client *cl, struct stat *s)
 411 {
 412         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 413
 414         if (hdr) {
 415                 uh_file_response_412(cl);
 416                 return false;
 417         }
 418
 419         return true;
 420 }
 421
 422 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 423 {
 424         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 425
 426         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 427                 uh_file_response_412(cl);
 428                 return false;
 429         }
 430
 431         return true;
 432 }
 433
 434
 435 static int uh_file_scandir_filter_dir(const struct dirent *e)
 436 {
 437         return strcmp(e->d_name, ".") ? 1 : 0;
 438 }
 439
 440 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 441 {
 442         int i;
 443         int count = 0;
 444         char filename[PATH_MAX];
 445         char *pathptr;
 446         struct dirent **files = NULL;
 447         struct stat s;
 448
 449         uh_file_response_200(cl, NULL);
 450         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 451
 452         uh_chunk_printf(cl,
 453                 "<html><head><title>Index of %s</title></head>"
 454                 "<body><h1>Index of %s</h1><hr /><ol>",
 455                 pi->name, pi->name);
 456
 457         if ((count = scandir(pi->phys, &files, uh_file_scandir_filter_dir,
 458                                                  alphasort)) > 0)
 459         {
 460                 memset(filename, 0, sizeof(filename));
 461                 memcpy(filename, pi->phys, sizeof(filename));
 462                 pathptr = &filename[strlen(filename)];
 463
 464                 /* list subdirs */
 465                 for (i = 0; i < count; i++) {
 466                         strncat(filename, files[i]->d_name,
 467                                         sizeof(filename) - strlen(files[i]->d_name));
 468
 469                         if (!stat(filename, &s) &&
 470                                 (s.st_mode & S_IFDIR) && (s.st_mode & S_IXOTH))
 471                                 uh_chunk_printf(cl,
 472                                         "<li><strong><a href='%s%s/'>%s</a>/"
 473                                         "</strong><br /><small>modified: %s"
 474                                         "<br />directory - %.02f kbyte<br />"
 475                                         "<br /></small></li>",
 476                                         pi->name, files[i]->d_name,
 477                                         files[i]->d_name,
 478                                         uh_file_unix2date(s.st_mtime),
 479                                         s.st_size / 1024.0);
 480
 481                         *pathptr = 0;
 482                 }
 483
 484                 /* list files */
 485                 for (i = 0; i < count; i++) {
 486                         strncat(filename, files[i]->d_name,
 487                                         sizeof(filename) - strlen(files[i]->d_name));
 488
 489                         if (!stat(filename, &s) &&
 490                                 !(s.st_mode & S_IFDIR) && (s.st_mode & S_IROTH))
 491                                 uh_chunk_printf(cl,
 492                                         "<li><strong><a href='%s%s'>%s</a>"
 493                                         "</strong><br /><small>modified: %s"
 494                                         "<br />%s - %.02f kbyte<br />"
 495                                         "<br /></small></li>",
 496                                         pi->name, files[i]->d_name,
 497                                         files[i]->d_name,
 498                                         uh_file_unix2date(s.st_mtime),
 499                                         uh_file_mime_lookup(filename),
 500                                         s.st_size / 1024.0);
 501
 502                         *pathptr = 0;
 503                 }
 504         }
 505
 506         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 507         uh_request_done(cl);
 508
 509         if (files)
 510         {
 511                 for (i = 0; i < count; i++)
 512                         free(files[i]);
 513
 514                 free(files);
 515         }
 516 }
 517
 518 static void file_write_cb(struct client *cl)
 519 {
 520         int fd = cl->dispatch.file.fd;
 521         int r;
 522
 523         while (cl->us->w.data_bytes < 256) {
 524                 r = read(fd, uh_buf, sizeof(uh_buf));
 525                 if (r < 0) {
 526                         if (errno == EINTR)
 527                                 continue;
 528                 }
 529
 530                 if (!r) {
 531                         uh_request_done(cl);
 532                         return;
 533                 }
 534
 535                 uh_chunk_write(cl, uh_buf, r);
 536         }
 537 }
 538
 539 static void uh_file_free(struct client *cl)
 540 {
 541         close(cl->dispatch.file.fd);
 542 }
 543
 544 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 545 {
 546         /* test preconditions */
 547         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 548                 !uh_file_if_match(cl, &pi->stat) ||
 549                 !uh_file_if_range(cl, &pi->stat) ||
 550                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 551                 !uh_file_if_none_match(cl, &pi->stat)) {
 552                 uh_request_done(cl);
 553                 close(fd);
 554                 return;
 555         }
 556
 557         /* write status */
 558         uh_file_response_200(cl, &pi->stat);
 559
 560         ustream_printf(cl->us, "Content-Type: %s\r\n",
 561                            uh_file_mime_lookup(pi->name));
 562
 563         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 564                            pi->stat.st_size);
 565
 566
 567         /* send body */
 568         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 569                 uh_request_done(cl);
 570                 close(fd);
 571                 return;
 572         }
 573
 574         cl->dispatch.file.fd = fd;
 575         cl->dispatch.write_cb = file_write_cb;
 576         cl->dispatch.free = uh_file_free;
 577         cl->dispatch.close_fds = uh_file_free;
 578         file_write_cb(cl);
 579 }
 580
 581 static void uh_file_request(struct client *cl, const char *url, struct path_info *pi)
 582 {
 583         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 584                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 585                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 586                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 587                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 588                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 589         };
 590         struct blob_attr *tb[__HDR_MAX];
 591         int fd;
 592
 593         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 594
 595         cl->dispatch.file.hdr = tb;
 596
 597         if (!(pi->stat.st_mode & S_IROTH))
 598                 goto error;
 599
 600         if (pi->stat.st_mode & S_IFREG) {
 601                 fd = open(pi->phys, O_RDONLY);
 602                 if (fd < 0)
 603                         goto error;
 604
 605                 uh_file_data(cl, pi, fd);
 606         } else if ((pi->stat.st_mode & S_IFDIR)) {
 607                 if (conf.no_dirlists)
 608                         goto error;
 609
 610                 uh_file_dirlist(cl, pi);
 611         } else {
 612                 goto error;
 613         }
 614
 615         cl->dispatch.file.hdr = NULL;
 616         return;
 617
 618 error:
 619         uh_client_error(cl, 403, "Forbidden",
 620                         "You don't have permission to access %s on this server.",
 621                         url);
 622         cl->dispatch.file.hdr = NULL;
 623 }
 624
 625 void uh_dispatch_add(struct dispatch_handler *d)
 626 {
 627         list_add_tail(&d->list, &dispatch_handlers);
 628 }
 629
 630 static struct dispatch_handler *
 631 dispatch_find(const char *url, struct path_info *pi)
 632 {
 633         struct dispatch_handler *d;
 634
 635         list_for_each_entry(d, &dispatch_handlers, list) {
 636                 if (pi) {
 637                         if (d->check_url)
 638                                 continue;
 639
 640                         if (d->check_path(pi, url))
 641                                 return d;
 642                 } else {
 643                         if (d->check_path)
 644                                 continue;
 645
 646                         if (d->check_url(url))
 647                                 return d;
 648                 }
 649         }
 650
 651         return NULL;
 652 }
 653
 654 static bool __handle_file_request(struct client *cl, const char *url)
 655 {
 656         struct dispatch_handler *d;
 657         struct path_info *pi;
 658
 659         pi = uh_path_lookup(cl, url);
 660         if (!pi)
 661                 return false;
 662
 663         if (pi->redirected)
 664                 return true;
 665
 666         d = dispatch_find(url, pi);
 667         if (d)
 668                 d->handle_request(cl, url, pi);
 669         else
 670                 uh_file_request(cl, url, pi);
 671
 672         return true;
 673 }
 674
 675 void uh_handle_request(struct client *cl)
 676 {
 677         struct dispatch_handler *d;
 678         const char *url = cl->request.url;
 679
 680         d = dispatch_find(url, NULL);
 681         if (d) {
 682                 d->handle_request(cl, url, NULL);
 683                 return;
 684         }
 685
 686         if (__handle_file_request(cl, url) ||
 687             __handle_file_request(cl, conf.error_handler))
 688                 return;
 689
 690         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", cl->request.url);
 691 }