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