file.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2013 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  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, "Content-Length: 0\r\n");
 226                 ustream_printf(cl->us, "Location: %s%s%s\r\n\r\n",
 227                                 &path_phys[docroot_len],
 228                                 p.query ? "?" : "",
 229                                 p.query ? p.query : "");
 230                 uh_request_done(cl);
 231                 p.redirected = 1;
 232                 return &p;
 233         }
 234
 235         /* try to locate index file */
 236         len = path_phys + sizeof(path_phys) - pathptr - 1;
 237         list_for_each_entry(idx, &index_files, list) {
 238                 if (strlen(idx->name) > len)
 239                         continue;
 240
 241                 strcpy(pathptr, idx->name);
 242                 if (!stat(path_phys, &s) && (s.st_mode & S_IFREG)) {
 243                         memcpy(&p.stat, &s, sizeof(p.stat));
 244                         break;
 245                 }
 246
 247                 *pathptr = 0;
 248         }
 249
 250         p.root = docroot;
 251         p.phys = path_phys;
 252         p.name = &path_phys[docroot_len];
 253
 254         return p.phys ? &p : NULL;
 255 }
 256
 257 static const char * uh_file_mime_lookup(const char *path)
 258 {
 259         const struct mimetype *m = &uh_mime_types[0];
 260         const char *e;
 261
 262         while (m->extn) {
 263                 e = &path[strlen(path)-1];
 264
 265                 while (e >= path) {
 266                         if ((*e == '.' || *e == '/') && !strcasecmp(&e[1], m->extn))
 267                                 return m->mime;
 268
 269                         e--;
 270                 }
 271
 272                 m++;
 273         }
 274
 275         return "application/octet-stream";
 276 }
 277
 278 static const char * uh_file_mktag(struct stat *s, char *buf, int len)
 279 {
 280         snprintf(buf, len, "\"%x-%x-%x\"",
 281                          (unsigned int) s->st_ino,
 282                          (unsigned int) s->st_size,
 283                          (unsigned int) s->st_mtime);
 284
 285         return buf;
 286 }
 287
 288 static time_t uh_file_date2unix(const char *date)
 289 {
 290         struct tm t;
 291
 292         memset(&t, 0, sizeof(t));
 293
 294         if (strptime(date, "%a, %d %b %Y %H:%M:%S %Z", &t) != NULL)
 295                 return timegm(&t);
 296
 297         return 0;
 298 }
 299
 300 static char * uh_file_unix2date(time_t ts, char *buf, int len)
 301 {
 302         struct tm *t = gmtime(&ts);
 303
 304         strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", t);
 305
 306         return buf;
 307 }
 308
 309 static char *uh_file_header(struct client *cl, int idx)
 310 {
 311         if (!cl->dispatch.file.hdr[idx])
 312                 return NULL;
 313
 314         return (char *) blobmsg_data(cl->dispatch.file.hdr[idx]);
 315 }
 316
 317 static void uh_file_response_ok_hdrs(struct client *cl, struct stat *s)
 318 {
 319         char buf[128];
 320
 321         if (s) {
 322                 ustream_printf(cl->us, "ETag: %s\r\n", uh_file_mktag(s, buf, sizeof(buf)));
 323                 ustream_printf(cl->us, "Last-Modified: %s\r\n",
 324                                uh_file_unix2date(s->st_mtime, buf, sizeof(buf)));
 325         }
 326         ustream_printf(cl->us, "Date: %s\r\n",
 327                        uh_file_unix2date(time(NULL), buf, sizeof(buf)));
 328 }
 329
 330 static void uh_file_response_200(struct client *cl, struct stat *s)
 331 {
 332         uh_http_header(cl, 200, "OK");
 333         return uh_file_response_ok_hdrs(cl, s);
 334 }
 335
 336 static void uh_file_response_304(struct client *cl, struct stat *s)
 337 {
 338         uh_http_header(cl, 304, "Not Modified");
 339
 340         return uh_file_response_ok_hdrs(cl, s);
 341 }
 342
 343 static void uh_file_response_412(struct client *cl)
 344 {
 345         uh_http_header(cl, 412, "Precondition Failed");
 346 }
 347
 348 static bool uh_file_if_match(struct client *cl, struct stat *s)
 349 {
 350         char buf[128];
 351         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 352         char *hdr = uh_file_header(cl, HDR_IF_MATCH);
 353         char *p;
 354         int i;
 355
 356         if (!hdr)
 357                 return true;
 358
 359         p = &hdr[0];
 360         for (i = 0; i < strlen(hdr); i++)
 361         {
 362                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 363                         hdr[i++] = 0;
 364                         p = &hdr[i];
 365                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 366                         return true;
 367                 }
 368         }
 369
 370         uh_file_response_412(cl);
 371         return false;
 372 }
 373
 374 static int uh_file_if_modified_since(struct client *cl, struct stat *s)
 375 {
 376         char *hdr = uh_file_header(cl, HDR_IF_MODIFIED_SINCE);
 377
 378         if (!hdr)
 379                 return true;
 380
 381         if (uh_file_date2unix(hdr) >= s->st_mtime) {
 382                 uh_file_response_304(cl, s);
 383                 return false;
 384         }
 385
 386         return true;
 387 }
 388
 389 static int uh_file_if_none_match(struct client *cl, struct stat *s)
 390 {
 391         char buf[128];
 392         const char *tag = uh_file_mktag(s, buf, sizeof(buf));
 393         char *hdr = uh_file_header(cl, HDR_IF_NONE_MATCH);
 394         char *p;
 395         int i;
 396
 397         if (!hdr)
 398                 return true;
 399
 400         p = &hdr[0];
 401         for (i = 0; i < strlen(hdr); i++) {
 402                 if ((hdr[i] == ' ') || (hdr[i] == ',')) {
 403                         hdr[i++] = 0;
 404                         p = &hdr[i];
 405                 } else if (!strcmp(p, "*") || !strcmp(p, tag)) {
 406                         if ((cl->request.method == UH_HTTP_MSG_GET) ||
 407                                 (cl->request.method == UH_HTTP_MSG_HEAD))
 408                                 uh_file_response_304(cl, s);
 409                         else
 410                                 uh_file_response_412(cl);
 411
 412                         return false;
 413                 }
 414         }
 415
 416         return true;
 417 }
 418
 419 static int uh_file_if_range(struct client *cl, struct stat *s)
 420 {
 421         char *hdr = uh_file_header(cl, HDR_IF_RANGE);
 422
 423         if (hdr) {
 424                 uh_file_response_412(cl);
 425                 return false;
 426         }
 427
 428         return true;
 429 }
 430
 431 static int uh_file_if_unmodified_since(struct client *cl, struct stat *s)
 432 {
 433         char *hdr = uh_file_header(cl, HDR_IF_UNMODIFIED_SINCE);
 434
 435         if (hdr && uh_file_date2unix(hdr) <= s->st_mtime) {
 436                 uh_file_response_412(cl);
 437                 return false;
 438         }
 439
 440         return true;
 441 }
 442
 443 static int dirent_cmp(const struct dirent **a, const struct dirent **b)
 444 {
 445         bool dir_a = !!((*a)->d_type & DT_DIR);
 446         bool dir_b = !!((*b)->d_type & DT_DIR);
 447
 448         /* directories first */
 449         if (dir_a != dir_b)
 450                 return dir_b - dir_a;
 451
 452         return alphasort(a, b);
 453 }
 454
 455 static void list_entries(struct client *cl, struct dirent **files, int count,
 456                          const char *path, char *local_path)
 457 {
 458         const char *suffix = "/";
 459         const char *type = "directory";
 460         unsigned int mode = S_IXOTH;
 461         struct stat s;
 462         char *file;
 463         char buf[128];
 464         int i;
 465
 466         file = local_path + strlen(local_path);
 467         for (i = 0; i < count; i++) {
 468                 const char *name = files[i]->d_name;
 469                 bool dir = !!(files[i]->d_type & DT_DIR);
 470
 471                 if (name[0] == '.' && name[1] == 0)
 472                         continue;
 473
 474                 sprintf(file, "%s", name);
 475                 if (stat(local_path, &s))
 476                         continue;
 477
 478                 if (!dir) {
 479                         suffix = "";
 480                         mode = S_IROTH;
 481                         type = uh_file_mime_lookup(local_path);
 482                 }
 483
 484                 if (!(s.st_mode & mode))
 485                         continue;
 486
 487                 uh_chunk_printf(cl,
 488                                 "<li><strong><a href='%s%s%s'>%s</a>%s"
 489                                 "</strong><br /><small>modified: %s"
 490                                 "<br />%s - %.02f kbyte<br />"
 491                                 "<br /></small></li>",
 492                                 path, name, suffix,
 493                                 name, suffix,
 494                                 uh_file_unix2date(s.st_mtime, buf, sizeof(buf)),
 495                                 type, s.st_size / 1024.0);
 496
 497                 *file = 0;
 498                 free(files[i]);
 499         }
 500 }
 501
 502 static void uh_file_dirlist(struct client *cl, struct path_info *pi)
 503 {
 504         struct dirent **files = NULL;
 505         int count = 0;
 506
 507         uh_file_response_200(cl, NULL);
 508         ustream_printf(cl->us, "Content-Type: text/html\r\n\r\n");
 509
 510         uh_chunk_printf(cl,
 511                 "<html><head><title>Index of %s</title></head>"
 512                 "<body><h1>Index of %s</h1><hr /><ol>",
 513                 pi->name, pi->name);
 514
 515         count = scandir(pi->phys, &files, NULL, dirent_cmp);
 516         if (count > 0) {
 517                 strcpy(uh_buf, pi->phys);
 518                 list_entries(cl, files, count, pi->name, uh_buf);
 519         }
 520         free(files);
 521
 522         uh_chunk_printf(cl, "</ol><hr /></body></html>");
 523         uh_request_done(cl);
 524 }
 525
 526 static void file_write_cb(struct client *cl)
 527 {
 528         int fd = cl->dispatch.file.fd;
 529         int r;
 530
 531         while (cl->us->w.data_bytes < 256) {
 532                 r = read(fd, uh_buf, sizeof(uh_buf));
 533                 if (r < 0) {
 534                         if (errno == EINTR)
 535                                 continue;
 536                 }
 537
 538                 if (!r) {
 539                         uh_request_done(cl);
 540                         return;
 541                 }
 542
 543                 uh_chunk_write(cl, uh_buf, r);
 544         }
 545 }
 546
 547 static void uh_file_free(struct client *cl)
 548 {
 549         close(cl->dispatch.file.fd);
 550 }
 551
 552 static void uh_file_data(struct client *cl, struct path_info *pi, int fd)
 553 {
 554         /* test preconditions */
 555         if (!uh_file_if_modified_since(cl, &pi->stat) ||
 556                 !uh_file_if_match(cl, &pi->stat) ||
 557                 !uh_file_if_range(cl, &pi->stat) ||
 558                 !uh_file_if_unmodified_since(cl, &pi->stat) ||
 559                 !uh_file_if_none_match(cl, &pi->stat)) {
 560                 ustream_printf(cl->us, "Content-Length: 0\r\n");
 561                 ustream_printf(cl->us, "\r\n");
 562                 uh_request_done(cl);
 563                 close(fd);
 564                 return;
 565         }
 566
 567         /* write status */
 568         uh_file_response_200(cl, &pi->stat);
 569
 570         ustream_printf(cl->us, "Content-Type: %s\r\n",
 571                            uh_file_mime_lookup(pi->name));
 572
 573         ustream_printf(cl->us, "Content-Length: %i\r\n\r\n",
 574                            pi->stat.st_size);
 575
 576
 577         /* send body */
 578         if (cl->request.method == UH_HTTP_MSG_HEAD) {
 579                 uh_request_done(cl);
 580                 close(fd);
 581                 return;
 582         }
 583
 584         cl->dispatch.file.fd = fd;
 585         cl->dispatch.write_cb = file_write_cb;
 586         cl->dispatch.free = uh_file_free;
 587         cl->dispatch.close_fds = uh_file_free;
 588         file_write_cb(cl);
 589 }
 590
 591 static void uh_file_request(struct client *cl, const char *url,
 592                             struct path_info *pi, struct blob_attr **tb)
 593 {
 594         int fd;
 595
 596         if (!(pi->stat.st_mode & S_IROTH))
 597                 goto error;
 598
 599         if (pi->stat.st_mode & S_IFREG) {
 600                 fd = open(pi->phys, O_RDONLY);
 601                 if (fd < 0)
 602                         goto error;
 603
 604                 cl->dispatch.file.hdr = tb;
 605                 uh_file_data(cl, pi, fd);
 606                 cl->dispatch.file.hdr = NULL;
 607                 return;
 608         }
 609
 610         if ((pi->stat.st_mode & S_IFDIR)) {
 611                 if (conf.no_dirlists)
 612                         goto error;
 613
 614                 uh_file_dirlist(cl, pi);
 615                 return;
 616         }
 617
 618 error:
 619         uh_client_error(cl, 403, "Forbidden",
 620                         "You don't have permission to access %s on this server.",
 621                         url);
 622 }
 623
 624 void uh_dispatch_add(struct dispatch_handler *d)
 625 {
 626         list_add_tail(&d->list, &dispatch_handlers);
 627 }
 628
 629 static struct dispatch_handler *
 630 dispatch_find(const char *url, struct path_info *pi)
 631 {
 632         struct dispatch_handler *d;
 633
 634         list_for_each_entry(d, &dispatch_handlers, list) {
 635                 if (pi) {
 636                         if (d->check_url)
 637                                 continue;
 638
 639                         if (d->check_path(pi, url))
 640                                 return d;
 641                 } else {
 642                         if (d->check_path)
 643                                 continue;
 644
 645                         if (d->check_url(url))
 646                                 return d;
 647                 }
 648         }
 649
 650         return NULL;
 651 }
 652
 653 static bool __handle_file_request(struct client *cl, char *url)
 654 {
 655         static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
 656                 [HDR_AUTHORIZATION] = { "authorization", BLOBMSG_TYPE_STRING },
 657                 [HDR_IF_MODIFIED_SINCE] = { "if-modified-since", BLOBMSG_TYPE_STRING },
 658                 [HDR_IF_UNMODIFIED_SINCE] = { "if-unmodified-since", BLOBMSG_TYPE_STRING },
 659                 [HDR_IF_MATCH] = { "if-match", BLOBMSG_TYPE_STRING },
 660                 [HDR_IF_NONE_MATCH] = { "if-none-match", BLOBMSG_TYPE_STRING },
 661                 [HDR_IF_RANGE] = { "if-range", BLOBMSG_TYPE_STRING },
 662         };
 663         struct dispatch_handler *d;
 664         struct blob_attr *tb[__HDR_MAX];
 665         struct path_info *pi;
 666
 667         pi = uh_path_lookup(cl, url);
 668         if (!pi)
 669                 return false;
 670
 671         if (pi->redirected)
 672                 return true;
 673
 674         blobmsg_parse(hdr_policy, __HDR_MAX, tb, blob_data(cl->hdr.head), blob_len(cl->hdr.head));
 675         if (tb[HDR_AUTHORIZATION])
 676                 pi->auth = blobmsg_data(tb[HDR_AUTHORIZATION]);
 677
 678         if (!uh_auth_check(cl, pi))
 679                 return true;
 680
 681         d = dispatch_find(url, pi);
 682         if (d)
 683                 d->handle_request(cl, url, pi);
 684         else
 685                 uh_file_request(cl, url, pi, tb);
 686
 687         return true;
 688 }
 689
 690 void uh_handle_request(struct client *cl)
 691 {
 692         struct http_request *req = &cl->request;
 693         struct dispatch_handler *d;
 694         char *url = blobmsg_data(blob_data(cl->hdr.head));;
 695         char *error_handler;
 696
 697         req->redirect_status = 200;
 698         d = dispatch_find(url, NULL);
 699         if (d) {
 700                 d->handle_request(cl, url, NULL);
 701                 return;
 702         }
 703
 704         if (__handle_file_request(cl, url))
 705                 return;
 706
 707         req->redirect_status = 404;
 708         if (conf.error_handler) {
 709                 error_handler = alloca(strlen(conf.error_handler) + 1);
 710                 strcpy(error_handler, conf.error_handler);
 711                 if (__handle_file_request(cl, error_handler))
 712                         return;
 713         }
 714
 715         uh_client_error(cl, 404, "Not Found", "The requested URL %s was not found on this server.", url);
 716 }