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_AUTHORIZATION,
  44         HDR_IF_MODIFIED_SINCE,
  45         HDR_IF_UNMODIFIED_SINCE,
  46         HDR_IF_MATCH,
  47         HDR_IF_NONE_MATCH,
  48         HDR_IF_RANGE,
  49         __HDR_MAX
  50 };
  51
  52 void uh_index_add(const char *filename)
  53 {
  54         struct index_file *idx;
  55
  56         idx = calloc(1, sizeof(*idx));
  57         idx->name = filename;
  58         list_add_tail(&idx->list, &index_files);
  59 }
  60
  61 static char * canonpath(const char *path, char *path_resolved)
  62 {
  63         const char *path_cpy = path;
  64         char *path_res = path_resolved;
  65
  66         if (conf.no_symlinks)
  67                 return realpath(path, path_resolved);
  68
  69         /* normalize */
  70         while ((*path_cpy != '\0') && (path_cpy < (path + PATH_MAX - 2))) {
  71                 if (*path_cpy != '/')
  72                         goto next;
  73
  74                 /* skip repeating / */
  75                 if (path_cpy[1] == '/') {
  76                         path_cpy++;
  77                         continue;
  78                 }
  79
  80                 /* /./ or /../ */
  81                 if (path_cpy[1] == '.') {
  82                         /* skip /./ */
  83                         if ((path_cpy[2] == '/') || (path_cpy[2] == '\0')) {
  84                                 path_cpy += 2;
  85                                 continue;
  86                         }
  87
  88                         /* collapse /x/../ */
  89                         if ((path_cpy[2] == '.') &&
  90                             ((path_cpy[3] == '/') || (path_cpy[3] == '\0'))) {
  91                                 while ((path_res > path_resolved) && (*--path_res != '/'));
  92
  93                                 path_cpy += 3;
  94                                 continue;
  95                         }
  96                 }
  97
  98 next:
  99                 *path_res++ = *path_cpy++;
 100         }
 101
 102         /* remove trailing slash if not root / */
 103         if ((path_res > (path_resolved+1)) && (path_res[-1] == '/'))
 104                 path_res--;
 105         else if (path_res == path_resolved)
 106                 *path_res++ = '/';
 107
 108         *path_res = '\0';
 109
 110         return path_resolved;
 111 }
 112
 113 /* Returns NULL on error.
 114 ** NB: improperly encoded URL should give client 400 [Bad Syntax]; returning
 115 ** NULL here causes 404 [Not Found], but that's not too unreasonable. */
 116 static struct path_info *
 117 uh_path_lookup(struct client *cl, const char *url)
 118 {
 119         static char path_phys[PATH_MAX];
 120         static char path_info[PATH_MAX];
 121         static struct path_info p;
 122
 123         const char *docroot = conf.docroot;
 124         int docroot_len = strlen(docroot);
 125         char *pathptr = NULL;
 126         bool slash;
 127
 128         int i = 0;
 129         int len;
 130         struct stat s;
 131         struct index_file *idx;
 132
 133         /* back out early if url is undefined */
 134         if (url == NULL)
 135                 return NULL;
 136
 137         memset(&p, 0, sizeof(p));
 138         path_phys[0] = 0;
 139         path_info[0] = 0;
 140
 141         strcpy(uh_buf, docroot);
 142
 143         /* separate query string from url */
 144         if ((pathptr = strchr(url, '?')) != NULL) {
 145                 p.query = pathptr[1] ? pathptr + 1 : NULL;
 146
 147                 /* urldecode component w/o query */
 148                 if (pathptr > url) {
 149                         if (uh_urldecode(&uh_buf[docroot_len],
 150                                          sizeof(uh_buf) - docroot_len - 1,
 151                                          url, pathptr - url ) < 0)
 152                                 return NULL;
 153                 }
 154         }
 155
 156         /* no query string, decode all of url */
 157         else if (uh_urldecode(&uh_buf[docroot_len],
 158                               sizeof(uh_buf) - docroot_len - 1,
 159                               url, strlen(url) ) < 0)
 160                 return NULL;
 161
 162         /* create canon path */
 163         len = strlen(uh_buf);
 164         slash = len && uh_buf[len - 1] == '/';
 165         len = min(len, sizeof(path_phys) - 1);
 166
 167         for (i = len; i >= 0; i--) {
 168                 char ch = uh_buf[i];
 169                 bool exists;
 170
 171                 if (ch != 0 && ch != '/')
 172                         continue;
 173
 174                 uh_buf[i] = 0;
 175                 exists = !!canonpath(uh_buf, path_phys);
 176                 uh_buf[i] = ch;
 177
 178                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 179                 break;
 180         }
 181
 182         /* check whether found path is within docroot */
 183         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 184             (path_phys[docroot_len] != 0 &&
 185              path_phys[docroot_len] != '/'))
 186                 return NULL;
 187
 188         /* test current path */
 189         if (stat(path_phys, &p.stat))
 190                 return NULL;
 191
 192         /* is a regular file */
 193         if (p.stat.st_mode & S_IFREG) {
 194                 p.root = docroot;
 195                 p.phys = path_phys;
 196                 p.name = &path_phys[docroot_len];
 197                 p.info = path_info[0] ? path_info : NULL;
 198                 return &p;
 199         }
 200
 201         if (!(p.stat.st_mode & S_IFDIR))
 202                 return NULL;
 203
 204         if (path_info[0])
 205             return NULL;
 206
 207         pathptr = path_phys + strlen(path_phys);
 208
 209         /* ensure trailing slash */
 210         if (pathptr[-1] != '/') {
 211                 pathptr[0] = '/';
 212                 pathptr[1] = 0;
 213                 pathptr++;
 214         }
 215
 216         /* if requested url resolves to a directory and a trailing slash
 217            is missing in the request url, redirect the client to the same
 218            url with trailing slash appended */
 219         if (!slash) {
 220                 uh_http_header(cl, 302, "Found");
 221                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 222                                 &path_phys[docroot_len],
 223                                 p.query ? "?" : "",
 224                                 p.query ? p.query : "");
 225                 uh_request_done(cl);
 226                 p.redirected = 1;
 227                 return &p;
 228         }
 229
 230         /* try to locate index file */
 231         len = path_phys + sizeof(path_phys) - pathptr - 1;
 232         list_for_each_entry(idx, &index_files, list) {
 233                 if (strlen(idx->name) > len)
 234                         continue;
 235
 236                 strcpy(pathptr, idx->name);
 237                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG))
 238                         break;
 239
 240                 *pathptr = 0;
 241         }
 242
 243         p.root = docroot;
 244         p.phys = path_phys;
 245         p.name = &path_phys[docroot_len];
 246
 247         return p.phys ? &p : NULL;
 248 }
 249
 250 #ifdef __APPLE__
 251 time_t timegm (struct tm *tm);
 252 #endif
 253
 254 static const char * uh_file_mime_lookup(const char *path)
 255 {
 256         struct mimetype *m = &uh_mime_types[0];
 257         const char *e;
 258
 259         while (m->extn) {
 260                 e = &path[strlen(path)-1];
 261
 262                 while (e >= path) {
 263                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 264                                 return m->mime;
 265
 266                         e--;
 267                 }
 268
 269                 m++;
 270         }
 271
 272         return "application/octet-stream";
 273 }
 274
 275 static const char * uh_file_mktag(struct stat *s)
 276 {
 277         snprintf(_tag, sizeof(_tag), "\"%x-%x-%x\"",
 278                          (unsigned int) s->st_ino,
 279                          (unsigned int) s->st_size,
 280                          (unsigned int) s->st_mtime);
 281
 282         return _tag;
 283 }
 284
 285 static time_t uh_file_date2unix(const char *date)
 286 {
 287         struct tm t;
 288
 289         memset(&t, 0, sizeof(t));
 290
 291         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 292                 return timegm(&t);
 293
 294         return 0;
 295 }
 296
 297 static char * uh_file_unix2date(time_t ts)
 298 {
 299         struct tm *t = gmtime(&ts);
 300
 301         strftime(_tag, sizeof(_tag), "%a, %d %b %Y %H:%M:%S GMT", t);
 302
 303         return _tag;
 304 }
 305
 306 static char *uh_file_header(struct client *cl, int idx)
 307 {
 308         if (!cl->dispatch.file.hdr[idx])
 309                 return NULL;
 310
 311         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 312 }
 313
 314 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 315 {
 316         if (s) {
 317                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s));
 318                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 319                                uh_file_unix2date(s->st_mtime));
 320         }
 321         ustream_printf(cl->us, "Date: %s\r\n", uh_file_unix2date(time(NULL)));
 322 }
 323
 324 static void uh_file_response_200(struct client *cl, struct stat *s)
 325 {
 326         uh_http_header(cl, 200, "OK");
 327         return uh_file_response_ok_hdrs(cl, s);
 328 }
 329
 330 static void uh_file_response_304(struct client *cl, struct stat *s)
 331 {
 332         uh_http_header(cl, 304, "Not Modified");
 333
 334         return uh_file_response_ok_hdrs(cl, s);
 335 }
 336
 337 static void uh_file_response_412(struct client *cl)
 338 {
 339         uh_http_header(cl, 412, "Precondition Failed");
 340 }
 341
 342 static bool uh_file_if_match(struct client *cl, struct stat *s)
 343 {
 344         const char *tag = uh_file_mktag(s);
 345         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 346         char *p;
 347         int i;
 348
 349         if (!hdr)
 350                 return true;
 351
 352         p = &hdr[0];
 353         for (i = 0; i < strlen(hdr); i++)
 354         {
 355                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 356                         hdr[i++] = 0;
 357                         p = &hdr[i];
 358                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 359                         return true;
 360                 }
 361         }
 362
 363         uh_file_response_412(cl);
 364         return false;
 365 }
 366
 367 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 368 {
 369         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 370
 371         if (!hdr)
 372                 return true;
 373
 374         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 375                 uh_file_response_304(cl, s);
 376                 return false;
 377         }
 378
 379         return true;
 380 }
 381
 382 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 383 {
 384         const char *tag = uh_file_mktag(s);
 385         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 386         char *p;
 387         int i;
 388
 389         if (!hdr)
 390                 return true;
 391
 392         p = &hdr[0];
 393         for (i = 0; i < strlen(hdr); i++) {
 394                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 395                         hdr[i++] = 0;
 396                         p = &hdr[i];
 397                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 398                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 399                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 400                                 uh_file_response_304(cl, s);
 401                         else
 402                                 uh_file_response_412(cl);
 403
 404                         return false;
 405                 }
 406         }
 407
 408         return true;
 409 }
 410
 411 static int uh_file_if_range(struct client *cl, struct stat *s)
 412 {
 413         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 414
 415         if (hdr) {
 416                 uh_file_response_412(cl);
 417                 return false;
 418         }
 419
 420         return true;
 421 }
 422
 423 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 424 {
 425         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 426
 427         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 428                 uh_file_response_412(cl);
 429                 return false;
 430         }
 431
 432         return true;
 433 }
 434
 435
 436 static int uh_file_scandir_filter_dir(const struct dirent *e)
 437 {
 438         return strcmp(e->d_name, ".") ? 1 : 0;
 439 }
 440
 441 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 442 {
 443         int i;
 444         int count = 0;
 445         char filename[PATH_MAX];
 446         char *pathptr;
 447         struct dirent **files = NULL;
 448         struct stat s;
 449
 450         uh_file_response_200(cl, NULL);
 451         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 452
 453         uh_chunk_printf(cl,
 454                 "<html><head><title>Index of %s</title></head>"
 455                 "<body><h1>Index of %s</h1><hr /><ol>",
 456                 pi->name, pi->name);
 457
 458         if ((count = scandir(pi->phys, &files, uh_file_scandir_filter_dir,
 459                                                  alphasort)) > 0)
 460         {
 461                 memset(filename, 0, sizeof(filename));
 462                 memcpy(filename, pi->phys, sizeof(filename));
 463                 pathptr = &filename[strlen(filename)];
 464
 465                 /* list subdirs */
 466                 for (i = 0; i < count; i++) {
 467                         strncat(filename, files[i]->d_name,
 468                                         sizeof(filename) - strlen(files[i]->d_name));
 469
 470                         if (!stat(filename, &s) &&
 471                                 (s.st_mode & S_IFDIR) && (s.st_mode & S_IXOTH))
 472                                 uh_chunk_printf(cl,
 473                                         "<li><strong><a href='%s%s/'>%s</a>/"
 474                                         "</strong><br /><small>modified: %s"
 475                                         "<br />directory - %.02f kbyte<br />"
 476                                         "<br /></small></li>",
 477                                         pi->name, files[i]->d_name,
 478                                         files[i]->d_name,
 479                                         uh_file_unix2date(s.st_mtime),
 480                                         s.st_size / 1024.0);
 481
 482                         *pathptr = 0;
 483                 }
 484
 485                 /* list files */
 486                 for (i = 0; i < count; i++) {
 487                         strncat(filename, files[i]->d_name,
 488                                         sizeof(filename) - strlen(files[i]->d_name));
 489
 490                         if (!stat(filename, &s) &&
 491                                 !(s.st_mode & S_IFDIR) && (s.st_mode & S_IROTH))
 492                                 uh_chunk_printf(cl,
 493                                         "<li><strong><a href='%s%s'>%s</a>"
 494                                         "</strong><br /><small>modified: %s"
 495                                         "<br />%s - %.02f kbyte<br />"
 496                                         "<br /></small></li>",
 497                                         pi->name, files[i]->d_name,
 498                                         files[i]->d_name,
 499                                         uh_file_unix2date(s.st_mtime),
 500                                         uh_file_mime_lookup(filename),
 501                                         s.st_size / 1024.0);
 502
 503                         *pathptr = 0;
 504                 }
 505         }
 506
 507         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 508         uh_request_done(cl);
 509
 510         if (files)
 511         {
 512                 for (i = 0; i < count; i++)
 513                         free(files[i]);
 514
 515                 free(files);
 516         }
 517 }
 518
 519 static void file_write_cb(struct client *cl)
 520 {
 521         int fd = cl->dispatch.file.fd;
 522         int r;
 523
 524         while (cl->us->w.data_bytes < 256) {
 525                 r = read(fd, uh_buf, sizeof(uh_buf));
 526                 if (r < 0) {
 527                         if (errno == EINTR)
 528                                 continue;
 529                 }
 530
 531                 if (!r) {
 532                         uh_request_done(cl);
 533                         return;
 534                 }
 535
 536                 uh_chunk_write(cl, uh_buf, r);
 537         }
 538 }
 539
 540 static void uh_file_free(struct client *cl)
 541 {
 542         close(cl->dispatch.file.fd);
 543 }
 544
 545 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 546 {
 547         /* test preconditions */
 548         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 549                 !uh_file_if_match(cl, &pi->stat) ||
 550                 !uh_file_if_range(cl, &pi->stat) ||
 551                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 552                 !uh_file_if_none_match(cl, &pi->stat)) {
 553                 uh_request_done(cl);
 554                 close(fd);
 555                 return;
 556         }
 557
 558         /* write status */
 559         uh_file_response_200(cl, &pi->stat);
 560
 561         ustream_printf(cl->us, "Content-Type: %s\r\n",
 562                            uh_file_mime_lookup(pi->name));
 563
 564         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 565                            pi->stat.st_size);
 566
 567
 568         /* send body */
 569         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 570                 uh_request_done(cl);
 571                 close(fd);
 572                 return;
 573         }
 574
 575         cl->dispatch.file.fd = fd;
 576         cl->dispatch.write_cb = file_write_cb;
 577         cl->dispatch.free = uh_file_free;
 578         cl->dispatch.close_fds = uh_file_free;
 579         file_write_cb(cl);
 580 }
 581
 582 static void uh_file_request(struct client *cl, const char *url,
 583                             struct path_info *pi, struct blob_attr **tb)
 584 {
 585         int fd;
 586
 587         if (!(pi->stat.st_mode & S_IROTH))
 588                 goto error;
 589
 590         if (pi->stat.st_mode & S_IFREG) {
 591                 fd = open(pi->phys, O_RDONLY);
 592                 if (fd < 0)
 593                         goto error;
 594
 595                 cl->dispatch.file.hdr = tb;
 596                 uh_file_data(cl, pi, fd);
 597                 cl->dispatch.file.hdr = NULL;
 598                 return;
 599         }
 600
 601         if ((pi->stat.st_mode & S_IFDIR)) {
 602                 if (conf.no_dirlists)
 603                         goto error;
 604
 605                 uh_file_dirlist(cl, pi);
 606                 return;
 607         }
 608
 609 error:
 610         uh_client_error(cl, 403, "Forbidden",
 611                         "You don't have permission to access %s on this server.",
 612                         url);
 613 }
 614
 615 void uh_dispatch_add(struct dispatch_handler *d)
 616 {
 617         list_add_tail(&d->list, &dispatch_handlers);
 618 }
 619
 620 static struct dispatch_handler *
 621 dispatch_find(const char *url, struct path_info *pi)
 622 {
 623         struct dispatch_handler *d;
 624
 625         list_for_each_entry(d, &dispatch_handlers, list) {
 626                 if (pi) {
 627                         if (d->check_url)
 628                                 continue;
 629
 630                         if (d->check_path(pi, url))
 631                                 return d;
 632                 } else {
 633                         if (d->check_path)
 634                                 continue;
 635
 636                         if (d->check_url(url))
 637                                 return d;
 638                 }
 639         }
 640
 641         return NULL;
 642 }
 643
 644 static bool __handle_file_request(struct client *cl, const char *url)
 645 {
 646         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 647                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 648                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 649                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 650                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 651                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 652                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 653         };
 654         struct dispatch_handler *d;
 655         struct blob_attr *tb[__HDR_MAX];
 656         struct path_info *pi;
 657
 658         pi = uh_path_lookup(cl, url);
 659         if (!pi)
 660                 return false;
 661
 662         if (pi->redirected)
 663                 return true;
 664
 665         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 666         if (tb[HDR_AUTHORIZATION])
 667                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 668
 669         if (!uh_auth_check(cl, pi))
 670                 return true;
 671
 672         d = dispatch_find(url, pi);
 673         if (d)
 674                 d->handle_request(cl, url, pi);
 675         else
 676                 uh_file_request(cl, url, pi, tb);
 677
 678         return true;
 679 }
 680
 681 void uh_handle_request(struct client *cl)
 682 {
 683         struct dispatch_handler *d;
 684         const char *url = cl->request.url;
 685
 686         d = dispatch_find(url, NULL);
 687         if (d) {
 688                 d->handle_request(cl, url, NULL);
 689                 return;
 690         }
 691
 692         if (__handle_file_request(cl, url) ||
 693             __handle_file_request(cl, conf.error_handler))
 694                 return;
 695
 696         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", cl->request.url);
 697 }