release/src/router/dnscrypt/src/libevent/sample/http-server.c

   1 /*
   2   A trivial static http webserver using Libevent's evhttp.
   3
   4   This is not the best code in the world, and it does some fairly stupid stuff
   5   that you would never want to do in a production webserver. Caveat hackor!
   6
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15
  16 #ifdef WIN32
  17 #include <winsock2.h>
  18 #include <ws2tcpip.h>
  19 #include <windows.h>
  20 #include <io.h>
  21 #include <fcntl.h>
  22 #ifndef S_ISDIR
  23 #define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR)
  24 #endif
  25 #else
  26 #include <sys/stat.h>
  27 #include <sys/socket.h>
  28 #include <signal.h>
  29 #include <fcntl.h>
  30 #include <unistd.h>
  31 #include <dirent.h>
  32 #endif
  33
  34 #include <event2/event.h>
  35 #include <event2/http.h>
  36 #include <event2/buffer.h>
  37 #include <event2/util.h>
  38 #include <event2/keyvalq_struct.h>
  39
  40 #ifdef _EVENT_HAVE_NETINET_IN_H
  41 #include <netinet/in.h>
  42 # ifdef _XOPEN_SOURCE_EXTENDED
  43 #  include <arpa/inet.h>
  44 # endif
  45 #endif
  46
  47 /* Compatibility for possible missing IPv6 declarations */
  48 #include "../util-internal.h"
  49
  50 #ifdef WIN32
  51 #define stat _stat
  52 #define fstat _fstat
  53 #define open _open
  54 #define close _close
  55 #define O_RDONLY _O_RDONLY
  56 #endif
  57
  58 char uri_root[512];
  59
  60 static const struct table_entry {
  61         const char *extension;
  62         const char *content_type;
  63 } content_type_table[] = {
  64         { "txt", "text/plain" },
  65         { "c", "text/plain" },
  66         { "h", "text/plain" },
  67         { "html", "text/html" },
  68         { "htm", "text/htm" },
  69         { "css", "text/css" },
  70         { "gif", "image/gif" },
  71         { "jpg", "image/jpeg" },
  72         { "jpeg", "image/jpeg" },
  73         { "png", "image/png" },
  74         { "pdf", "application/pdf" },
  75         { "ps", "application/postsript" },
  76         { NULL, NULL },
  77 };
  78
  79 /* Try to guess a good content-type for 'path' */
  80 static const char *
  81 guess_content_type(const char *path)
  82 {
  83         const char *last_period, *extension;
  84         const struct table_entry *ent;
  85         last_period = strrchr(path, '.');
  86         if (!last_period || strchr(last_period, '/'))
  87                 goto not_found; /* no exension */
  88         extension = last_period + 1;
  89         for (ent = &content_type_table[0]; ent->extension; ++ent) {
  90                 if (!evutil_ascii_strcasecmp(ent->extension, extension))
  91                         return ent->content_type;
  92         }
  93
  94 not_found:
  95         return "application/misc";
  96 }
  97
  98 /* Callback used for the /dump URI, and for every non-GET request:
  99  * dumps all information to stdout and gives back a trivial 200 ok */
 100 static void
 101 dump_request_cb(struct evhttp_request *req, void *arg)
 102 {
 103         const char *cmdtype;
 104         struct evkeyvalq *headers;
 105         struct evkeyval *header;
 106         struct evbuffer *buf;
 107
 108         switch (evhttp_request_get_command(req)) {
 109         case EVHTTP_REQ_GET: cmdtype = "GET"; break;
 110         case EVHTTP_REQ_POST: cmdtype = "POST"; break;
 111         case EVHTTP_REQ_HEAD: cmdtype = "HEAD"; break;
 112         case EVHTTP_REQ_PUT: cmdtype = "PUT"; break;
 113         case EVHTTP_REQ_DELETE: cmdtype = "DELETE"; break;
 114         case EVHTTP_REQ_OPTIONS: cmdtype = "OPTIONS"; break;
 115         case EVHTTP_REQ_TRACE: cmdtype = "TRACE"; break;
 116         case EVHTTP_REQ_CONNECT: cmdtype = "CONNECT"; break;
 117         case EVHTTP_REQ_PATCH: cmdtype = "PATCH"; break;
 118         default: cmdtype = "unknown"; break;
 119         }
 120
 121         printf("Received a %s request for %s\nHeaders:\n",
 122             cmdtype, evhttp_request_get_uri(req));
 123
 124         headers = evhttp_request_get_input_headers(req);
 125         for (header = headers->tqh_first; header;
 126             header = header->next.tqe_next) {
 127                 printf("  %s: %s\n", header->key, header->value);
 128         }
 129
 130         buf = evhttp_request_get_input_buffer(req);
 131         puts("Input data: <<<");
 132         while (evbuffer_get_length(buf)) {
 133                 int n;
 134                 char cbuf[128];
 135                 n = evbuffer_remove(buf, cbuf, sizeof(buf)-1);
 136                 if (n > 0)
 137                         (void) fwrite(cbuf, 1, n, stdout);
 138         }
 139         puts(">>>");
 140
 141         evhttp_send_reply(req, 200, "OK", NULL);
 142 }
 143
 144 /* This callback gets invoked when we get any http request that doesn't match
 145  * any other callback.  Like any evhttp server callback, it has a simple job:
 146  * it must eventually call evhttp_send_error() or evhttp_send_reply().
 147  */
 148 static void
 149 send_document_cb(struct evhttp_request *req, void *arg)
 150 {
 151         struct evbuffer *evb = NULL;
 152         const char *docroot = arg;
 153         const char *uri = evhttp_request_get_uri(req);
 154         struct evhttp_uri *decoded = NULL;
 155         const char *path;
 156         char *decoded_path;
 157         char *whole_path = NULL;
 158         size_t len;
 159         int fd = -1;
 160         struct stat st;
 161
 162         if (evhttp_request_get_command(req) != EVHTTP_REQ_GET) {
 163                 dump_request_cb(req, arg);
 164                 return;
 165         }
 166
 167         printf("Got a GET request for <%s>\n",  uri);
 168
 169         /* Decode the URI */
 170         decoded = evhttp_uri_parse(uri);
 171         if (!decoded) {
 172                 printf("It's not a good URI. Sending BADREQUEST\n");
 173                 evhttp_send_error(req, HTTP_BADREQUEST, 0);
 174                 return;
 175         }
 176
 177         /* Let's see what path the user asked for. */
 178         path = evhttp_uri_get_path(decoded);
 179         if (!path) path = "/";
 180
 181         /* We need to decode it, to see what path the user really wanted. */
 182         decoded_path = evhttp_uridecode(path, 0, NULL);
 183         if (decoded_path == NULL)
 184                 goto err;
 185         /* Don't allow any ".."s in the path, to avoid exposing stuff outside
 186          * of the docroot.  This test is both overzealous and underzealous:
 187          * it forbids aceptable paths like "/this/one..here", but it doesn't
 188          * do anything to prevent symlink following." */
 189         if (strstr(decoded_path, ".."))
 190                 goto err;
 191
 192         len = strlen(decoded_path)+strlen(docroot)+2;
 193         if (!(whole_path = malloc(len))) {
 194                 perror("malloc");
 195                 goto err;
 196         }
 197         evutil_snprintf(whole_path, len, "%s/%s", docroot, decoded_path);
 198
 199         if (stat(whole_path, &st)<0) {
 200                 goto err;
 201         }
 202
 203         /* This holds the content we're sending. */
 204         evb = evbuffer_new();
 205
 206         if (S_ISDIR(st.st_mode)) {
 207                 /* If it's a directory, read the comments and make a little
 208                  * index page */
 209 #ifdef WIN32
 210                 HANDLE d;
 211                 WIN32_FIND_DATAA ent;
 212                 char *pattern;
 213                 size_t dirlen;
 214 #else
 215                 DIR *d;
 216                 struct dirent *ent;
 217 #endif
 218                 const char *trailing_slash = "";
 219
 220                 if (!strlen(path) || path[strlen(path)-1] != '/')
 221                         trailing_slash = "/";
 222
 223 #ifdef WIN32
 224                 dirlen = strlen(whole_path);
 225                 pattern = malloc(dirlen+3);
 226                 memcpy(pattern, whole_path, dirlen);
 227                 pattern[dirlen] = '\\';
 228                 pattern[dirlen+1] = '*';
 229                 pattern[dirlen+2] = '\0';
 230                 d = FindFirstFileA(pattern, &ent);
 231                 free(pattern);
 232                 if (d == INVALID_HANDLE_VALUE)
 233                         goto err;
 234 #else
 235                 if (!(d = opendir(whole_path)))
 236                         goto err;
 237 #endif
 238
 239                 evbuffer_add_printf(evb, "<html>\n <head>\n"
 240                     "  <title>%s</title>\n"
 241                     "  <base href='%s%s%s'>\n"
 242                     " </head>\n"
 243                     " <body>\n"
 244                     "  <h1>%s</h1>\n"
 245                     "  <ul>\n",
 246                     decoded_path, /* XXX html-escape this. */
 247                     uri_root, path, /* XXX html-escape this? */
 248                     trailing_slash,
 249                     decoded_path /* XXX html-escape this */);
 250 #ifdef WIN32
 251                 do {
 252                         const char *name = ent.cFileName;
 253 #else
 254                 while ((ent = readdir(d))) {
 255                         const char *name = ent->d_name;
 256 #endif
 257                         evbuffer_add_printf(evb,
 258                             "    <li><a href=\"%s\">%s</a>\n",
 259                             name, name);/* XXX escape this */
 260 #ifdef WIN32
 261                 } while (FindNextFileA(d, &ent));
 262 #else
 263                 }
 264 #endif
 265                 evbuffer_add_printf(evb, "</ul></body></html>\n");
 266 #ifdef WIN32
 267                 CloseHandle(d);
 268 #else
 269                 closedir(d);
 270 #endif
 271                 evhttp_add_header(evhttp_request_get_output_headers(req),
 272                     "Content-Type", "text/html");
 273         } else {
 274                 /* Otherwise it's a file; add it to the buffer to get
 275                  * sent via sendfile */
 276                 const char *type = guess_content_type(decoded_path);
 277                 if ((fd = open(whole_path, O_RDONLY)) < 0) {
 278                         perror("open");
 279                         goto err;
 280                 }
 281
 282                 if (fstat(fd, &st)<0) {
 283                         /* Make sure the length still matches, now that we
 284                          * opened the file :/ */
 285                         perror("fstat");
 286                         goto err;
 287                 }
 288                 evhttp_add_header(evhttp_request_get_output_headers(req),
 289                     "Content-Type", type);
 290                 evbuffer_add_file(evb, fd, 0, st.st_size);
 291         }
 292
 293         evhttp_send_reply(req, 200, "OK", evb);
 294         goto done;
 295 err:
 296         evhttp_send_error(req, 404, "Document was not found");
 297         if (fd>=0)
 298                 close(fd);
 299 done:
 300         if (decoded)
 301                 evhttp_uri_free(decoded);
 302         if (decoded_path)
 303                 free(decoded_path);
 304         if (whole_path)
 305                 free(whole_path);
 306         if (evb)
 307                 evbuffer_free(evb);
 308 }
 309
 310 static void
 311 syntax(void)
 312 {
 313         fprintf(stdout, "Syntax: http-server <docroot>\n");
 314 }
 315
 316 int
 317 main(int argc, char **argv)
 318 {
 319         struct event_base *base;
 320         struct evhttp *http;
 321         struct evhttp_bound_socket *handle;
 322
 323         unsigned short port = 0;
 324 #ifdef WIN32
 325         WSADATA WSAData;
 326         WSAStartup(0x101, &WSAData);
 327 #else
 328         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 329                 return (1);
 330 #endif
 331         if (argc < 2) {
 332                 syntax();
 333                 return 1;
 334         }
 335
 336         base = event_base_new();
 337         if (!base) {
 338                 fprintf(stderr, "Couldn't create an event_base: exiting\n");
 339                 return 1;
 340         }
 341
 342         /* Create a new evhttp object to handle requests. */
 343         http = evhttp_new(base);
 344         if (!http) {
 345                 fprintf(stderr, "couldn't create evhttp. Exiting.\n");
 346                 return 1;
 347         }
 348
 349         /* The /dump URI will dump all requests to stdout and say 200 ok. */
 350         evhttp_set_cb(http, "/dump", dump_request_cb, NULL);
 351
 352         /* We want to accept arbitrary requests, so we need to set a "generic"
 353          * cb.  We can also add callbacks for specific paths. */
 354         evhttp_set_gencb(http, send_document_cb, argv[1]);
 355
 356         /* Now we tell the evhttp what port to listen on */
 357         handle = evhttp_bind_socket_with_handle(http, "0.0.0.0", port);
 358         if (!handle) {
 359                 fprintf(stderr, "couldn't bind to port %d. Exiting.\n",
 360                     (int)port);
 361                 return 1;
 362         }
 363
 364         {
 365                 /* Extract and display the address we're listening on. */
 366                 struct sockaddr_storage ss;
 367                 evutil_socket_t fd;
 368                 ev_socklen_t socklen = sizeof(ss);
 369                 char addrbuf[128];
 370                 void *inaddr;
 371                 const char *addr;
 372                 int got_port = -1;
 373                 fd = evhttp_bound_socket_get_fd(handle);
 374                 memset(&ss, 0, sizeof(ss));
 375                 if (getsockname(fd, (struct sockaddr *)&ss, &socklen)) {
 376                         perror("getsockname() failed");
 377                         return 1;
 378                 }
 379                 if (ss.ss_family == AF_INET) {
 380                         got_port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
 381                         inaddr = &((struct sockaddr_in*)&ss)->sin_addr;
 382                 } else if (ss.ss_family == AF_INET6) {
 383                         got_port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
 384                         inaddr = &((struct sockaddr_in6*)&ss)->sin6_addr;
 385                 } else {
 386                         fprintf(stderr, "Weird address family %d\n",
 387                             ss.ss_family);
 388                         return 1;
 389                 }
 390                 addr = evutil_inet_ntop(ss.ss_family, inaddr, addrbuf,
 391                     sizeof(addrbuf));
 392                 if (addr) {
 393                         printf("Listening on %s:%d\n", addr, got_port);
 394                         evutil_snprintf(uri_root, sizeof(uri_root),
 395                             "http://%s:%d",addr,got_port);
 396                 } else {
 397                         fprintf(stderr, "evutil_inet_ntop failed\n");
 398                         return 1;
 399                 }
 400         }
 401
 402         event_base_dispatch(base);
 403
 404         return 0;
 405 }