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                 snprintf(path_info, sizeof(path_info), "%s", uh_buf + i);
 180                 break;
 181         }
 182
 183         /* check whether found path is within docroot */
 184         if (strncmp(path_phys, docroot, docroot_len) != 0 ||
 185             (path_phys[docroot_len] != 0 &&
 186              path_phys[docroot_len] != '/'))
 187                 return NULL;
 188
 189         /* test current path */
 190         if (stat(path_phys, &p.stat))
 191                 return NULL;
 192
 193         /* is a regular file */
 194         if (p.stat.st_mode & S_IFREG) {
 195                 p.root = docroot;
 196                 p.phys = path_phys;
 197                 p.name = &path_phys[docroot_len];
 198                 p.info = path_info[0] ? path_info : NULL;
 199                 return &p;
 200         }
 201
 202         if (!(p.stat.st_mode & S_IFDIR))
 203                 return NULL;
 204
 205         if (path_info[0])
 206             return NULL;
 207
 208         pathptr = path_phys + strlen(path_phys);
 209
 210         /* ensure trailing slash */
 211         if (pathptr[-1] != '/') {
 212                 pathptr[0] = '/';
 213                 pathptr[1] = 0;
 214                 pathptr++;
 215         }
 216
 217         /* if requested url resolves to a directory and a trailing slash
 218            is missing in the request url, redirect the client to the same
 219            url with trailing slash appended */
 220         if (!slash) {
 221                 uh_http_header(cl, 302, "Found");
 222                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 223                                 &path_phys[docroot_len],
 224                                 p.query ? "?" : "",
 225                                 p.query ? p.query : "");
 226                 uh_request_done(cl);
 227                 p.redirected = 1;
 228                 return &p;
 229         }
 230
 231         /* try to locate index file */
 232         len = path_phys + sizeof(path_phys) - pathptr - 1;
 233         list_for_each_entry(idx, &index_files, list) {
 234                 if (strlen(idx->name) > len)
 235                         continue;
 236
 237                 strcpy(pathptr, idx->name);
 238                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG)) {
 239                         memcpy(&p.stat, &s, sizeof(p.stat));
 240                         break;
 241                 }
 242
 243                 *pathptr = 0;
 244         }
 245
 246         p.root = docroot;
 247         p.phys = path_phys;
 248         p.name = &path_phys[docroot_len];
 249
 250         return p.phys ? &p : NULL;
 251 }
 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, char *buf)
 275 {
 276         snprintf(buf, sizeof(buf), "\"%x-%x-%x\"",
 277                          (unsigned int) s->st_ino,
 278                          (unsigned int) s->st_size,
 279                          (unsigned int) s->st_mtime);
 280
 281         return buf;
 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, char *buf, int len)
 297 {
 298         struct tm *t = gmtime(&ts);
 299
 300         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 301
 302         return buf;
 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         char buf[128];
 316
 317         if (s) {
 318                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf));
 319                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 320                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 321         }
 322         ustream_printf(cl->us, "Date: %s\r\n",
 323                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 324 }
 325
 326 static void uh_file_response_200(struct client *cl, struct stat *s)
 327 {
 328         uh_http_header(cl, 200, "OK");
 329         return uh_file_response_ok_hdrs(cl, s);
 330 }
 331
 332 static void uh_file_response_304(struct client *cl, struct stat *s)
 333 {
 334         uh_http_header(cl, 304, "Not Modified");
 335
 336         return uh_file_response_ok_hdrs(cl, s);
 337 }
 338
 339 static void uh_file_response_412(struct client *cl)
 340 {
 341         uh_http_header(cl, 412, "Precondition Failed");
 342 }
 343
 344 static bool uh_file_if_match(struct client *cl, struct stat *s)
 345 {
 346         char buf[128];
 347         const char *tag = uh_file_mktag(s, buf);
 348         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 349         char *p;
 350         int i;
 351
 352         if (!hdr)
 353                 return true;
 354
 355         p = &hdr[0];
 356         for (i = 0; i < strlen(hdr); i++)
 357         {
 358                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 359                         hdr[i++] = 0;
 360                         p = &hdr[i];
 361                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 362                         return true;
 363                 }
 364         }
 365
 366         uh_file_response_412(cl);
 367         return false;
 368 }
 369
 370 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 371 {
 372         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 373
 374         if (!hdr)
 375                 return true;
 376
 377         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 378                 uh_file_response_304(cl, s);
 379                 return false;
 380         }
 381
 382         return true;
 383 }
 384
 385 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 386 {
 387         char buf[128];
 388         const char *tag = uh_file_mktag(s, buf);
 389         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 390         char *p;
 391         int i;
 392
 393         if (!hdr)
 394                 return true;
 395
 396         p = &hdr[0];
 397         for (i = 0; i < strlen(hdr); i++) {
 398                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 399                         hdr[i++] = 0;
 400                         p = &hdr[i];
 401                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 402                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 403                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 404                                 uh_file_response_304(cl, s);
 405                         else
 406                                 uh_file_response_412(cl);
 407
 408                         return false;
 409                 }
 410         }
 411
 412         return true;
 413 }
 414
 415 static int uh_file_if_range(struct client *cl, struct stat *s)
 416 {
 417         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 418
 419         if (hdr) {
 420                 uh_file_response_412(cl);
 421                 return false;
 422         }
 423
 424         return true;
 425 }
 426
 427 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 428 {
 429         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 430
 431         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 432                 uh_file_response_412(cl);
 433                 return false;
 434         }
 435
 436         return true;
 437 }
 438
 439 static int dirent_cmp(const struct dirent **a, const struct dirent **b)
 440 {
 441         bool dir_a = !!((*a)->d_type & DT_DIR);
 442         bool dir_b = !!((*b)->d_type & DT_DIR);
 443
 444         /* directories first */
 445         if (dir_a != dir_b)
 446                 return dir_b - dir_a;
 447
 448         return alphasort(a, b);
 449 }
 450
 451 static void list_entries(struct client *cl, struct dirent **files, int count,
 452                          const char *path, char *local_path)
 453 {
 454         const char *suffix = "/";
 455         const char *type = "directory";
 456         unsigned int mode = S_IXOTH;
 457         struct stat s;
 458         char *file;
 459         char buf[128];
 460         int i;
 461
 462         file = local_path + strlen(local_path);
 463         for (i = 0; i < count; i++) {
 464                 const char *name = files[i]->d_name;
 465                 bool dir = !!(files[i]->d_type & DT_DIR);
 466
 467                 if (name[0] == '.' && name[1] == 0)
 468                         continue;
 469
 470                 sprintf(file, "%s", name);
 471                 if (stat(local_path, &s))
 472                         continue;
 473
 474                 if (!dir) {
 475                         suffix = "";
 476                         mode = S_IROTH;
 477                         type = uh_file_mime_lookup(local_path);
 478                 }
 479
 480                 if (!(s.st_mode & mode))
 481                         continue;
 482
 483                 uh_chunk_printf(cl,
 484                                 "<li><strong><a href='%s%s%s'>%s</a>%s"
 485                                 "</strong><br /><small>modified: %s"
 486                                 "<br />%s - %.02f kbyte<br />"
 487                                 "<br /></small></li>",
 488                                 path, name, suffix,
 489                                 name, suffix,
 490                                 uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 491                                 type, s.st_size / 1024.0);
 492
 493                 *file = 0;
 494                 free(files[i]);
 495         }
 496 }
 497
 498 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 499 {
 500         struct dirent **files = NULL;
 501         int count = 0;
 502
 503         uh_file_response_200(cl, NULL);
 504         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 505
 506         uh_chunk_printf(cl,
 507                 "<html><head><title>Index of %s</title></head>"
 508                 "<body><h1>Index of %s</h1><hr /><ol>",
 509                 pi->name, pi->name);
 510
 511         count = scandir(pi->phys, &files, NULL, dirent_cmp);
 512         if (count > 0) {
 513                 strcpy(uh_buf, pi->phys);
 514                 list_entries(cl, files, count, pi->name, uh_buf);
 515         }
 516         free(files);
 517
 518         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 519         uh_request_done(cl);
 520 }
 521
 522 static void file_write_cb(struct client *cl)
 523 {
 524         int fd = cl->dispatch.file.fd;
 525         int r;
 526
 527         while (cl->us->w.data_bytes < 256) {
 528                 r = read(fd, uh_buf, sizeof(uh_buf));
 529                 if (r < 0) {
 530                         if (errno == EINTR)
 531                                 continue;
 532                 }
 533
 534                 if (!r) {
 535                         uh_request_done(cl);
 536                         return;
 537                 }
 538
 539                 uh_chunk_write(cl, uh_buf, r);
 540         }
 541 }
 542
 543 static void uh_file_free(struct client *cl)
 544 {
 545         close(cl->dispatch.file.fd);
 546 }
 547
 548 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 549 {
 550         /* test preconditions */
 551         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 552                 !uh_file_if_match(cl, &pi->stat) ||
 553                 !uh_file_if_range(cl, &pi->stat) ||
 554                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 555                 !uh_file_if_none_match(cl, &pi->stat)) {
 556                 uh_request_done(cl);
 557                 close(fd);
 558                 return;
 559         }
 560
 561         /* write status */
 562         uh_file_response_200(cl, &pi->stat);
 563
 564         ustream_printf(cl->us, "Content-Type: %s\r\n",
 565                            uh_file_mime_lookup(pi->name));
 566
 567         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 568                            pi->stat.st_size);
 569
 570
 571         /* send body */
 572         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 573                 uh_request_done(cl);
 574                 close(fd);
 575                 return;
 576         }
 577
 578         cl->dispatch.file.fd = fd;
 579         cl->dispatch.write_cb = file_write_cb;
 580         cl->dispatch.free = uh_file_free;
 581         cl->dispatch.close_fds = uh_file_free;
 582         file_write_cb(cl);
 583 }
 584
 585 static void uh_file_request(struct client *cl, const char *url,
 586                             struct path_info *pi, struct blob_attr **tb)
 587 {
 588         int fd;
 589
 590         if (!(pi->stat.st_mode & S_IROTH))
 591                 goto error;
 592
 593         if (pi->stat.st_mode & S_IFREG) {
 594                 fd = open(pi->phys, O_RDONLY);
 595                 if (fd < 0)
 596                         goto error;
 597
 598                 cl->dispatch.file.hdr = tb;
 599                 uh_file_data(cl, pi, fd);
 600                 cl->dispatch.file.hdr = NULL;
 601                 return;
 602         }
 603
 604         if ((pi->stat.st_mode & S_IFDIR)) {
 605                 if (conf.no_dirlists)
 606                         goto error;
 607
 608                 uh_file_dirlist(cl, pi);
 609                 return;
 610         }
 611
 612 error:
 613         uh_client_error(cl, 403, "Forbidden",
 614                         "You don't have permission to access %s on this server.",
 615                         url);
 616 }
 617
 618 void uh_dispatch_add(struct dispatch_handler *d)
 619 {
 620         list_add_tail(&d->list, &dispatch_handlers);
 621 }
 622
 623 static struct dispatch_handler *
 624 dispatch_find(const char *url, struct path_info *pi)
 625 {
 626         struct dispatch_handler *d;
 627
 628         list_for_each_entry(d, &dispatch_handlers, list) {
 629                 if (pi) {
 630                         if (d->check_url)
 631                                 continue;
 632
 633                         if (d->check_path(pi, url))
 634                                 return d;
 635                 } else {
 636                         if (d->check_path)
 637                                 continue;
 638
 639                         if (d->check_url(url))
 640                                 return d;
 641                 }
 642         }
 643
 644         return NULL;
 645 }
 646
 647 static bool __handle_file_request(struct client *cl, const char *url)
 648 {
 649         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 650                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 651                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 652                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 653                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 654                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 655                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 656         };
 657         struct dispatch_handler *d;
 658         struct blob_attr *tb[__HDR_MAX];
 659         struct path_info *pi;
 660
 661         pi = uh_path_lookup(cl, url);
 662         if (!pi)
 663                 return false;
 664
 665         if (pi->redirected)
 666                 return true;
 667
 668         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 669         if (tb[HDR_AUTHORIZATION])
 670                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 671
 672         if (!uh_auth_check(cl, pi))
 673                 return true;
 674
 675         d = dispatch_find(url, pi);
 676         if (d)
 677                 d->handle_request(cl, url, pi);
 678         else
 679                 uh_file_request(cl, url, pi, tb);
 680
 681         return true;
 682 }
 683
 684 void uh_handle_request(struct client *cl)
 685 {
 686         struct dispatch_handler *d;
 687         const char *url = blobmsg_data(blob_data(cl->hdr.head));;
 688
 689         d = dispatch_find(url, NULL);
 690         if (d) {
 691                 d->handle_request(cl, url, NULL);
 692                 return;
 693         }
 694
 695         if (__handle_file_request(cl, url) ||
 696             __handle_file_request(cl, conf.error_handler))
 697                 return;
 698
 699         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", url);
 700 }