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 _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
  30 #include <libubox/blobmsg.h>
  31
  32 #include "uhttpd.h"
  33 #include "mimetypes.h"
  34
  35 static LIST_HEAD(index_files);
  36 static LIST_HEAD(dispatch_handlers);
  37
  38 struct index_file {
  39         struct list_head list;
  40         const char *name;
  41 };
  42
  43 enum file_hdr {
  44         HDR_AUTHORIZATION,
  45         HDR_IF_MODIFIED_SINCE,
  46         HDR_IF_UNMODIFIED_SINCE,
  47         HDR_IF_MATCH,
  48         HDR_IF_NONE_MATCH,
  49         HDR_IF_RANGE,
  50         __HDR_MAX
  51 };
  52
  53 void uh_index_add(const char *filename)
  54 {
  55         struct index_file *idx;
  56
  57         idx = calloc(1, sizeof(*idx));
  58         idx->name = filename;
  59         list_add_tail(&idx->list, &index_files);
  60 }
  61
  62 static char * canonpath(const char *path, char *path_resolved)
  63 {
  64         const char *path_cpy = path;
  65         char *path_res = path_resolved;
  66
  67         if (conf.no_symlinks)
  68                 return realpath(path, path_resolved);
  69
  70         /* normalize */
  71         while ((*path_cpy != '\0') && (path_cpy < (path + PATH_MAX - 2))) {
  72                 if (*path_cpy != '/')
  73                         goto next;
  74
  75                 /* skip repeating / */
  76                 if (path_cpy[1] == '/') {
  77                         path_cpy++;
  78                         continue;
  79                 }
  80
  81                 /* /./ or /../ */
  82                 if (path_cpy[1] == '.') {
  83                         /* skip /./ */
  84                         if ((path_cpy[2] == '/') || (path_cpy[2] == '\0')) {
  85                                 path_cpy += 2;
  86                                 continue;
  87                         }
  88
  89                         /* collapse /x/../ */
  90                         if ((path_cpy[2] == '.') &&
  91                             ((path_cpy[3] == '/') || (path_cpy[3] == '\0'))) {
  92                                 while ((path_res > path_resolved) && (*--path_res != '/'));
  93
  94                                 path_cpy += 3;
  95                                 continue;
  96                         }
  97                 }
  98
  99 next:
 100                 *path_res++ = *path_cpy++;
 101         }
 102
 103         /* remove trailing slash if not root / */
 104         if ((path_res > (path_resolved+1)) && (path_res[-1] == '/'))
 105                 path_res--;
 106         else if (path_res == path_resolved)
 107                 *path_res++ = '/';
 108
 109         *path_res = '\0';
 110
 111         return path_resolved;
 112 }
 113
 114 /* Returns NULL on error.
 115 ** NB: improperly encoded URL should give client 400 [Bad Syntax]; returning
 116 ** NULL here causes 404 [Not Found], but that's not too unreasonable. */
 117 static struct path_info *
 118 uh_path_lookup(struct client *cl, const char *url)
 119 {
 120         static char path_phys[PATH_MAX];
 121         static char path_info[PATH_MAX];
 122         static struct path_info p;
 123
 124         const char *docroot = conf.docroot;
 125         int docroot_len = strlen(docroot);
 126         char *pathptr = NULL;
 127         bool slash;
 128
 129         int i = 0;
 130         int len;
 131         struct stat s;
 132         struct index_file *idx;
 133
 134         /* back out early if url is undefined */
 135         if (url == NULL)
 136                 return NULL;
 137
 138         memset(&p, 0, sizeof(p));
 139         path_phys[0] = 0;
 140         path_info[0] = 0;
 141
 142         strcpy(uh_buf, docroot);
 143
 144         /* separate query string from url */
 145         if ((pathptr = strchr(url, '?')) != NULL) {
 146                 p.query = pathptr[1] ? pathptr + 1 : NULL;
 147
 148                 /* urldecode component w/o query */
 149                 if (pathptr > url) {
 150                         if (uh_urldecode(&uh_buf[docroot_len],
 151                                          sizeof(uh_buf) - docroot_len - 1,
 152                                          url, pathptr - url ) < 0)
 153                                 return NULL;
 154                 }
 155         }
 156
 157         /* no query string, decode all of url */
 158         else if (uh_urldecode(&uh_buf[docroot_len],
 159                               sizeof(uh_buf) - docroot_len - 1,
 160                               url, strlen(url) ) < 0)
 161                 return NULL;
 162
 163         /* create canon path */
 164         len = strlen(uh_buf);
 165         slash = len && uh_buf[len - 1] == '/';
 166         len = min(len, sizeof(path_phys) - 1);
 167
 168         for (i = len; i >= 0; i--) {
 169                 char ch = uh_buf[i];
 170                 bool exists;
 171
 172                 if (ch != 0 && ch != '/')
 173                         continue;
 174
 175                 uh_buf[i] = 0;
 176                 exists = !!canonpath(uh_buf, path_phys);
 177                 uh_buf[i] = ch;
 178
 179                 if (!exists)
 180                         continue;
 181
 182                 /* test current path */
 183                 if (stat(path_phys, &p.stat))
 184                         continue;
 185
 186                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 187                 break;
 188         }
 189
 190         /* check whether found path is within docroot */
 191         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 192             (path_phys[docroot_len] != 0 &&
 193              path_phys[docroot_len] != '/'))
 194                 return NULL;
 195
 196         /* is a regular file */
 197         if (p.stat.st_mode & S_IFREG) {
 198                 p.root = docroot;
 199                 p.phys = path_phys;
 200                 p.name = &path_phys[docroot_len];
 201                 p.info = path_info[0] ? path_info : NULL;
 202                 return &p;
 203         }
 204
 205         if (!(p.stat.st_mode & S_IFDIR))
 206                 return NULL;
 207
 208         if (path_info[0])
 209             return NULL;
 210
 211         pathptr = path_phys + strlen(path_phys);
 212
 213         /* ensure trailing slash */
 214         if (pathptr[-1] != '/') {
 215                 pathptr[0] = '/';
 216                 pathptr[1] = 0;
 217                 pathptr++;
 218         }
 219
 220         /* if requested url resolves to a directory and a trailing slash
 221            is missing in the request url, redirect the client to the same
 222            url with trailing slash appended */
 223         if (!slash) {
 224                 uh_http_header(cl, 302, "Found");
 225                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 226                                 &path_phys[docroot_len],
 227                                 p.query ? "?" : "",
 228                                 p.query ? p.query : "");
 229                 uh_request_done(cl);
 230                 p.redirected = 1;
 231                 return &p;
 232         }
 233
 234         /* try to locate index file */
 235         len = path_phys + sizeof(path_phys) - pathptr - 1;
 236         list_for_each_entry(idx, &index_files, list) {
 237                 if (strlen(idx->name) > len)
 238                         continue;
 239
 240                 strcpy(pathptr, idx->name);
 241                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG)) {
 242                         memcpy(&p.stat, &s, sizeof(p.stat));
 243                         break;
 244                 }
 245
 246                 *pathptr = 0;
 247         }
 248
 249         p.root = docroot;
 250         p.phys = path_phys;
 251         p.name = &path_phys[docroot_len];
 252
 253         return p.phys ? &p : NULL;
 254 }
 255
 256 static const char * uh_file_mime_lookup(const char *path)
 257 {
 258         const struct mimetype *m = &uh_mime_types[0];
 259         const char *e;
 260
 261         while (m->extn) {
 262                 e = &path[strlen(path)-1];
 263
 264                 while (e >= path) {
 265                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 266                                 return m->mime;
 267
 268                         e--;
 269                 }
 270
 271                 m++;
 272         }
 273
 274         return "application/octet-stream";
 275 }
 276
 277 static const char * uh_file_mktag(struct stat *s, char *buf)
 278 {
 279         snprintf(buf, sizeof(buf), "\"%x-%x-%x\"",
 280                          (unsigned int) s->st_ino,
 281                          (unsigned int) s->st_size,
 282                          (unsigned int) s->st_mtime);
 283
 284         return buf;
 285 }
 286
 287 static time_t uh_file_date2unix(const char *date)
 288 {
 289         struct tm t;
 290
 291         memset(&t, 0, sizeof(t));
 292
 293         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 294                 return timegm(&t);
 295
 296         return 0;
 297 }
 298
 299 static char * uh_file_unix2date(time_t ts, char *buf, int len)
 300 {
 301         struct tm *t = gmtime(&ts);
 302
 303         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 304
 305         return buf;
 306 }
 307
 308 static char *uh_file_header(struct client *cl, int idx)
 309 {
 310         if (!cl->dispatch.file.hdr[idx])
 311                 return NULL;
 312
 313         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 314 }
 315
 316 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 317 {
 318         char buf[128];
 319
 320         if (s) {
 321                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf));
 322                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 323                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 324         }
 325         ustream_printf(cl->us, "Date: %s\r\n",
 326                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 327 }
 328
 329 static void uh_file_response_200(struct client *cl, struct stat *s)
 330 {
 331         uh_http_header(cl, 200, "OK");
 332         return uh_file_response_ok_hdrs(cl, s);
 333 }
 334
 335 static void uh_file_response_304(struct client *cl, struct stat *s)
 336 {
 337         uh_http_header(cl, 304, "Not Modified");
 338
 339         return uh_file_response_ok_hdrs(cl, s);
 340 }
 341
 342 static void uh_file_response_412(struct client *cl)
 343 {
 344         uh_http_header(cl, 412, "Precondition Failed");
 345 }
 346
 347 static bool uh_file_if_match(struct client *cl, struct stat *s)
 348 {
 349         char buf[128];
 350         const char *tag = uh_file_mktag(s, buf);
 351         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 352         char *p;
 353         int i;
 354
 355         if (!hdr)
 356                 return true;
 357
 358         p = &hdr[0];
 359         for (i = 0; i < strlen(hdr); i++)
 360         {
 361                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 362                         hdr[i++] = 0;
 363                         p = &hdr[i];
 364                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 365                         return true;
 366                 }
 367         }
 368
 369         uh_file_response_412(cl);
 370         return false;
 371 }
 372
 373 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 374 {
 375         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 376
 377         if (!hdr)
 378                 return true;
 379
 380         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 381                 uh_file_response_304(cl, s);
 382                 return false;
 383         }
 384
 385         return true;
 386 }
 387
 388 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 389 {
 390         char buf[128];
 391         const char *tag = uh_file_mktag(s, buf);
 392         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 393         char *p;
 394         int i;
 395
 396         if (!hdr)
 397                 return true;
 398
 399         p = &hdr[0];
 400         for (i = 0; i < strlen(hdr); i++) {
 401                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 402                         hdr[i++] = 0;
 403                         p = &hdr[i];
 404                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 405                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 406                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 407                                 uh_file_response_304(cl, s);
 408                         else
 409                                 uh_file_response_412(cl);
 410
 411                         return false;
 412                 }
 413         }
 414
 415         return true;
 416 }
 417
 418 static int uh_file_if_range(struct client *cl, struct stat *s)
 419 {
 420         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 421
 422         if (hdr) {
 423                 uh_file_response_412(cl);
 424                 return false;
 425         }
 426
 427         return true;
 428 }
 429
 430 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 431 {
 432         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 433
 434         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 435                 uh_file_response_412(cl);
 436                 return false;
 437         }
 438
 439         return true;
 440 }
 441
 442 static int dirent_cmp(const struct dirent **a, const struct dirent **b)
 443 {
 444         bool dir_a = !!((*a)->d_type & DT_DIR);
 445         bool dir_b = !!((*b)->d_type & DT_DIR);
 446
 447         /* directories first */
 448         if (dir_a != dir_b)
 449                 return dir_b - dir_a;
 450
 451         return alphasort(a, b);
 452 }
 453
 454 static void list_entries(struct client *cl, struct dirent **files, int count,
 455                          const char *path, char *local_path)
 456 {
 457         const char *suffix = "/";
 458         const char *type = "directory";
 459         unsigned int mode = S_IXOTH;
 460         struct stat s;
 461         char *file;
 462         char buf[128];
 463         int i;
 464
 465         file = local_path + strlen(local_path);
 466         for (i = 0; i < count; i++) {
 467                 const char *name = files[i]->d_name;
 468                 bool dir = !!(files[i]->d_type & DT_DIR);
 469
 470                 if (name[0] == '.' && name[1] == 0)
 471                         continue;
 472
 473                 sprintf(file, "%s", name);
 474                 if (stat(local_path, &s))
 475                         continue;
 476
 477                 if (!dir) {
 478                         suffix = "";
 479                         mode = S_IROTH;
 480                         type = uh_file_mime_lookup(local_path);
 481                 }
 482
 483                 if (!(s.st_mode & mode))
 484                         continue;
 485
 486                 uh_chunk_printf(cl,
 487                                 "<li><strong><a href='%s%s%s'>%s</a>%s"
 488                                 "</strong><br /><small>modified: %s"
 489                                 "<br />%s - %.02f kbyte<br />"
 490                                 "<br /></small></li>",
 491                                 path, name, suffix,
 492                                 name, suffix,
 493                                 uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 494                                 type, s.st_size / 1024.0);
 495
 496                 *file = 0;
 497                 free(files[i]);
 498         }
 499 }
 500
 501 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 502 {
 503         struct dirent **files = NULL;
 504         int count = 0;
 505
 506         uh_file_response_200(cl, NULL);
 507         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 508
 509         uh_chunk_printf(cl,
 510                 "<html><head><title>Index of %s</title></head>"
 511                 "<body><h1>Index of %s</h1><hr /><ol>",
 512                 pi->name, pi->name);
 513
 514         count = scandir(pi->phys, &files, NULL, dirent_cmp);
 515         if (count > 0) {
 516                 strcpy(uh_buf, pi->phys);
 517                 list_entries(cl, files, count, pi->name, uh_buf);
 518         }
 519         free(files);
 520
 521         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 522         uh_request_done(cl);
 523 }
 524
 525 static void file_write_cb(struct client *cl)
 526 {
 527         int fd = cl->dispatch.file.fd;
 528         int r;
 529
 530         while (cl->us->w.data_bytes < 256) {
 531                 r = read(fd, uh_buf, sizeof(uh_buf));
 532                 if (r < 0) {
 533                         if (errno == EINTR)
 534                                 continue;
 535                 }
 536
 537                 if (!r) {
 538                         uh_request_done(cl);
 539                         return;
 540                 }
 541
 542                 uh_chunk_write(cl, uh_buf, r);
 543         }
 544 }
 545
 546 static void uh_file_free(struct client *cl)
 547 {
 548         close(cl->dispatch.file.fd);
 549 }
 550
 551 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 552 {
 553         /* test preconditions */
 554         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 555                 !uh_file_if_match(cl, &pi->stat) ||
 556                 !uh_file_if_range(cl, &pi->stat) ||
 557                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 558                 !uh_file_if_none_match(cl, &pi->stat)) {
 559                 uh_request_done(cl);
 560                 close(fd);
 561                 return;
 562         }
 563
 564         /* write status */
 565         uh_file_response_200(cl, &pi->stat);
 566
 567         ustream_printf(cl->us, "Content-Type: %s\r\n",
 568                            uh_file_mime_lookup(pi->name));
 569
 570         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 571                            pi->stat.st_size);
 572
 573
 574         /* send body */
 575         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 576                 uh_request_done(cl);
 577                 close(fd);
 578                 return;
 579         }
 580
 581         cl->dispatch.file.fd = fd;
 582         cl->dispatch.write_cb = file_write_cb;
 583         cl->dispatch.free = uh_file_free;
 584         cl->dispatch.close_fds = uh_file_free;
 585         file_write_cb(cl);
 586 }
 587
 588 static void uh_file_request(struct client *cl, const char *url,
 589                             struct path_info *pi, struct blob_attr **tb)
 590 {
 591         int fd;
 592
 593         if (!(pi->stat.st_mode & S_IROTH))
 594                 goto error;
 595
 596         if (pi->stat.st_mode & S_IFREG) {
 597                 fd = open(pi->phys, O_RDONLY);
 598                 if (fd < 0)
 599                         goto error;
 600
 601                 cl->dispatch.file.hdr = tb;
 602                 uh_file_data(cl, pi, fd);
 603                 cl->dispatch.file.hdr = NULL;
 604                 return;
 605         }
 606
 607         if ((pi->stat.st_mode & S_IFDIR)) {
 608                 if (conf.no_dirlists)
 609                         goto error;
 610
 611                 uh_file_dirlist(cl, pi);
 612                 return;
 613         }
 614
 615 error:
 616         uh_client_error(cl, 403, "Forbidden",
 617                         "You don't have permission to access %s on this server.",
 618                         url);
 619 }
 620
 621 void uh_dispatch_add(struct dispatch_handler *d)
 622 {
 623         list_add_tail(&d->list, &dispatch_handlers);
 624 }
 625
 626 static struct dispatch_handler *
 627 dispatch_find(const char *url, struct path_info *pi)
 628 {
 629         struct dispatch_handler *d;
 630
 631         list_for_each_entry(d, &dispatch_handlers, list) {
 632                 if (pi) {
 633                         if (d->check_url)
 634                                 continue;
 635
 636                         if (d->check_path(pi, url))
 637                                 return d;
 638                 } else {
 639                         if (d->check_path)
 640                                 continue;
 641
 642                         if (d->check_url(url))
 643                                 return d;
 644                 }
 645         }
 646
 647         return NULL;
 648 }
 649
 650 static bool __handle_file_request(struct client *cl, char *url)
 651 {
 652         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 653                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 654                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 655                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 656                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 657                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 658                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 659         };
 660         struct dispatch_handler *d;
 661         struct blob_attr *tb[__HDR_MAX];
 662         struct path_info *pi;
 663
 664         pi = uh_path_lookup(cl, url);
 665         if (!pi)
 666                 return false;
 667
 668         if (pi->redirected)
 669                 return true;
 670
 671         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 672         if (tb[HDR_AUTHORIZATION])
 673                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 674
 675         if (!uh_auth_check(cl, pi))
 676                 return true;
 677
 678         d = dispatch_find(url, pi);
 679         if (d)
 680                 d->handle_request(cl, url, pi);
 681         else
 682                 uh_file_request(cl, url, pi, tb);
 683
 684         return true;
 685 }
 686
 687 void uh_handle_request(struct client *cl)
 688 {
 689         struct http_request *req = &cl->request;
 690         struct dispatch_handler *d;
 691         char *url = blobmsg_data(blob_data(cl->hdr.head));;
 692         char *error_handler;
 693
 694         req->redirect_status = 200;
 695         d = dispatch_find(url, NULL);
 696         if (d) {
 697                 d->handle_request(cl, url, NULL);
 698                 return;
 699         }
 700
 701         if (__handle_file_request(cl, url))
 702                 return;
 703
 704         req->redirect_status = 404;
 705         if (conf.error_handler) {
 706                 error_handler = alloca(strlen(conf.error_handler) + 1);
 707                 strcpy(error_handler, conf.error_handler);
 708                 if (__handle_file_request(cl, error_handler))
 709                         return;
 710         }
 711
 712         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", url);
 713 }