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