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 LIST_HEAD(index_files);
  34 static LIST_HEAD(dispatch_handlers);
  35
  36 struct index_file {
  37         struct list_head list;
  38         const char *name;
  39 };
  40
  41 enum file_hdr {
  42         HDR_AUTHORIZATION,
  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 static const char * uh_file_mime_lookup(const char *path)
 250 {
 251         struct mimetype *m = &uh_mime_types[0];
 252         const char *e;
 253
 254         while (m->extn) {
 255                 e = &path[strlen(path)-1];
 256
 257                 while (e >= path) {
 258                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 259                                 return m->mime;
 260
 261                         e--;
 262                 }
 263
 264                 m++;
 265         }
 266
 267         return "application/octet-stream";
 268 }
 269
 270 static const char * uh_file_mktag(struct stat *s, char *buf)
 271 {
 272         snprintf(buf, sizeof(buf), "\"%x-%x-%x\"",
 273                          (unsigned int) s->st_ino,
 274                          (unsigned int) s->st_size,
 275                          (unsigned int) s->st_mtime);
 276
 277         return buf;
 278 }
 279
 280 static time_t uh_file_date2unix(const char *date)
 281 {
 282         struct tm t;
 283
 284         memset(&t, 0, sizeof(t));
 285
 286         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 287                 return timegm(&t);
 288
 289         return 0;
 290 }
 291
 292 static char * uh_file_unix2date(time_t ts, char *buf, int len)
 293 {
 294         struct tm *t = gmtime(&ts);
 295
 296         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 297
 298         return buf;
 299 }
 300
 301 static char *uh_file_header(struct client *cl, int idx)
 302 {
 303         if (!cl->dispatch.file.hdr[idx])
 304                 return NULL;
 305
 306         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 307 }
 308
 309 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 310 {
 311         char buf[128];
 312
 313         if (s) {
 314                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf));
 315                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 316                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 317         }
 318         ustream_printf(cl->us, "Date: %s\r\n",
 319                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 320 }
 321
 322 static void uh_file_response_200(struct client *cl, struct stat *s)
 323 {
 324         uh_http_header(cl, 200, "OK");
 325         return uh_file_response_ok_hdrs(cl, s);
 326 }
 327
 328 static void uh_file_response_304(struct client *cl, struct stat *s)
 329 {
 330         uh_http_header(cl, 304, "Not Modified");
 331
 332         return uh_file_response_ok_hdrs(cl, s);
 333 }
 334
 335 static void uh_file_response_412(struct client *cl)
 336 {
 337         uh_http_header(cl, 412, "Precondition Failed");
 338 }
 339
 340 static bool uh_file_if_match(struct client *cl, struct stat *s)
 341 {
 342         char buf[128];
 343         const char *tag = uh_file_mktag(s, buf);
 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         char buf[128];
 384         const char *tag = uh_file_mktag(s, buf);
 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 = uh_buf;
 446         char *pathptr;
 447         struct dirent **files = NULL;
 448         struct stat s;
 449         char buf[128];
 450
 451         uh_file_response_200(cl, NULL);
 452         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 453
 454         uh_chunk_printf(cl,
 455                 "<html><head><title>Index of %s</title></head>"
 456                 "<body><h1>Index of %s</h1><hr /><ol>",
 457                 pi->name, pi->name);
 458
 459         if ((count = scandir(pi->phys, &files, uh_file_scandir_filter_dir,
 460                                                  alphasort)) > 0)
 461         {
 462                 int len;
 463
 464                 strcpy(filename, pi->phys);
 465                 len = strlen(filename);
 466                 pathptr = filename + len;
 467                 len = PATH_MAX - len;
 468
 469                 /* list subdirs */
 470                 for (i = 0; i < count; i++) {
 471                         snprintf(pathptr, len, "%s", files[i]->d_name);
 472
 473                         if (!stat(filename, &s) &&
 474                                 (s.st_mode & S_IFDIR) && (s.st_mode & S_IXOTH))
 475                                 uh_chunk_printf(cl,
 476                                         "<li><strong><a href='%s%s/'>%s</a>/"
 477                                         "</strong><br /><small>modified: %s"
 478                                         "<br />directory - %.02f kbyte<br />"
 479                                         "<br /></small></li>",
 480                                         pi->name, files[i]->d_name,
 481                                         files[i]->d_name,
 482                                         uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 483                                         s.st_size / 1024.0);
 484
 485                         *pathptr = 0;
 486                 }
 487
 488                 /* list files */
 489                 for (i = 0; i < count; i++) {
 490                         snprintf(pathptr, len, "%s", files[i]->d_name);
 491
 492                         if (!stat(filename, &s) &&
 493                                 !(s.st_mode & S_IFDIR) && (s.st_mode & S_IROTH))
 494                                 uh_chunk_printf(cl,
 495                                         "<li><strong><a href='%s%s'>%s</a>"
 496                                         "</strong><br /><small>modified: %s"
 497                                         "<br />%s - %.02f kbyte<br />"
 498                                         "<br /></small></li>",
 499                                         pi->name, files[i]->d_name,
 500                                         files[i]->d_name,
 501                                         uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 502                                         uh_file_mime_lookup(filename),
 503                                         s.st_size / 1024.0);
 504
 505                         *pathptr = 0;
 506                 }
 507         }
 508
 509         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 510         uh_request_done(cl);
 511
 512         if (files)
 513         {
 514                 for (i = 0; i < count; i++)
 515                         free(files[i]);
 516
 517                 free(files);
 518         }
 519 }
 520
 521 static void file_write_cb(struct client *cl)
 522 {
 523         int fd = cl->dispatch.file.fd;
 524         int r;
 525
 526         while (cl->us->w.data_bytes < 256) {
 527                 r = read(fd, uh_buf, sizeof(uh_buf));
 528                 if (r < 0) {
 529                         if (errno == EINTR)
 530                                 continue;
 531                 }
 532
 533                 if (!r) {
 534                         uh_request_done(cl);
 535                         return;
 536                 }
 537
 538                 uh_chunk_write(cl, uh_buf, r);
 539         }
 540 }
 541
 542 static void uh_file_free(struct client *cl)
 543 {
 544         close(cl->dispatch.file.fd);
 545 }
 546
 547 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 548 {
 549         /* test preconditions */
 550         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 551                 !uh_file_if_match(cl, &pi->stat) ||
 552                 !uh_file_if_range(cl, &pi->stat) ||
 553                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 554                 !uh_file_if_none_match(cl, &pi->stat)) {
 555                 uh_request_done(cl);
 556                 close(fd);
 557                 return;
 558         }
 559
 560         /* write status */
 561         uh_file_response_200(cl, &pi->stat);
 562
 563         ustream_printf(cl->us, "Content-Type: %s\r\n",
 564                            uh_file_mime_lookup(pi->name));
 565
 566         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 567                            pi->stat.st_size);
 568
 569
 570         /* send body */
 571         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 572                 uh_request_done(cl);
 573                 close(fd);
 574                 return;
 575         }
 576
 577         cl->dispatch.file.fd = fd;
 578         cl->dispatch.write_cb = file_write_cb;
 579         cl->dispatch.free = uh_file_free;
 580         cl->dispatch.close_fds = uh_file_free;
 581         file_write_cb(cl);
 582 }
 583
 584 static void uh_file_request(struct client *cl, const char *url,
 585                             struct path_info *pi, struct blob_attr **tb)
 586 {
 587         int fd;
 588
 589         if (!(pi->stat.st_mode & S_IROTH))
 590                 goto error;
 591
 592         if (pi->stat.st_mode & S_IFREG) {
 593                 fd = open(pi->phys, O_RDONLY);
 594                 if (fd < 0)
 595                         goto error;
 596
 597                 cl->dispatch.file.hdr = tb;
 598                 uh_file_data(cl, pi, fd);
 599                 cl->dispatch.file.hdr = NULL;
 600                 return;
 601         }
 602
 603         if ((pi->stat.st_mode & S_IFDIR)) {
 604                 if (conf.no_dirlists)
 605                         goto error;
 606
 607                 uh_file_dirlist(cl, pi);
 608                 return;
 609         }
 610
 611 error:
 612         uh_client_error(cl, 403, "Forbidden",
 613                         "You don't have permission to access %s on this server.",
 614                         url);
 615 }
 616
 617 void uh_dispatch_add(struct dispatch_handler *d)
 618 {
 619         list_add_tail(&d->list, &dispatch_handlers);
 620 }
 621
 622 static struct dispatch_handler *
 623 dispatch_find(const char *url, struct path_info *pi)
 624 {
 625         struct dispatch_handler *d;
 626
 627         list_for_each_entry(d, &dispatch_handlers, list) {
 628                 if (pi) {
 629                         if (d->check_url)
 630                                 continue;
 631
 632                         if (d->check_path(pi, url))
 633                                 return d;
 634                 } else {
 635                         if (d->check_path)
 636                                 continue;
 637
 638                         if (d->check_url(url))
 639                                 return d;
 640                 }
 641         }
 642
 643         return NULL;
 644 }
 645
 646 static bool __handle_file_request(struct client *cl, const char *url)
 647 {
 648         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 649                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 650                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 651                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 652                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 653                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 654                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 655         };
 656         struct dispatch_handler *d;
 657         struct blob_attr *tb[__HDR_MAX];
 658         struct path_info *pi;
 659
 660         pi = uh_path_lookup(cl, url);
 661         if (!pi)
 662                 return false;
 663
 664         if (pi->redirected)
 665                 return true;
 666
 667         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 668         if (tb[HDR_AUTHORIZATION])
 669                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 670
 671         if (!uh_auth_check(cl, pi))
 672                 return true;
 673
 674         d = dispatch_find(url, pi);
 675         if (d)
 676                 d->handle_request(cl, url, pi);
 677         else
 678                 uh_file_request(cl, url, pi, tb);
 679
 680         return true;
 681 }
 682
 683 void uh_handle_request(struct client *cl)
 684 {
 685         struct dispatch_handler *d;
 686         const char *url = cl->request.url;
 687
 688         d = dispatch_find(url, NULL);
 689         if (d) {
 690                 d->handle_request(cl, url, NULL);
 691                 return;
 692         }
 693
 694         if (__handle_file_request(cl, url) ||
 695             __handle_file_request(cl, conf.error_handler))
 696                 return;
 697
 698         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", cl->request.url);
 699 }