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 /* Compatibility for possible missing IPv6 declarations */ 45 #include "../util-internal.h" 46 47 #ifdef WIN32 48 #define stat _stat 49 #define fstat _fstat 50 #define open _open 51 #define close _close 52 #define O_RDONLY _O_RDONLY 53 #endif 54 55 char uri_root[512]; 56 57 static const struct table_entry { 58 const char *extension; 59 const char *content_type; 60 } content_type_table[] = { 61 { "txt", "text/plain" }, 62 { "c", "text/plain" }, 63 { "h", "text/plain" }, 64 { "html", "text/html" }, 65 { "htm", "text/htm" }, 66 { "css", "text/css" }, 67 { "gif", "image/gif" }, 68 { "jpg", "image/jpeg" }, 69 { "jpeg", "image/jpeg" }, 70 { "png", "image/png" }, 71 { "pdf", "application/pdf" }, 72 { "ps", "application/postsript" }, 73 { NULL, NULL }, 74 }; 75 76 /* Try to guess a good content-type for 'path' */ 77 static const char * 78 guess_content_type(const char *path) 79 { 80 const char *last_period, *extension; 81 const struct table_entry *ent; 82 last_period = strrchr(path, '.'); 83 if (!last_period || strchr(last_period, '/')) 84 goto not_found; /* no exension */ 85 extension = last_period + 1; 86 for (ent = &content_type_table[0]; ent->extension; ++ent) { 87 if (!evutil_ascii_strcasecmp(ent->extension, extension)) 88 return ent->content_type; 89 } 90 91 not_found: 92 return "application/misc"; 93 } 94 95 /* Callback used for the /dump URI, and for every non-GET request: 96 * dumps all information to stdout and gives back a trivial 200 ok */ 97 static void 98 dump_request_cb(struct evhttp_request *req, void *arg) 99 { 100 const char *cmdtype; 101 struct evkeyvalq *headers; 102 struct evkeyval *header; 103 struct evbuffer *buf; 104 105 switch (evhttp_request_get_command(req)) { 106 case EVHTTP_REQ_GET: cmdtype = "GET"; break; 107 case EVHTTP_REQ_POST: cmdtype = "POST"; break; 108 case EVHTTP_REQ_HEAD: cmdtype = "HEAD"; break; 109 case EVHTTP_REQ_PUT: cmdtype = "PUT"; break; 110 case EVHTTP_REQ_DELETE: cmdtype = "DELETE"; break; 111 case EVHTTP_REQ_OPTIONS: cmdtype = "OPTIONS"; break; 112 case EVHTTP_REQ_TRACE: cmdtype = "TRACE"; break; 113 case EVHTTP_REQ_CONNECT: cmdtype = "CONNECT"; break; 114 case EVHTTP_REQ_PATCH: cmdtype = "PATCH"; break; 115 default: cmdtype = "unknown"; break; 116 } 117 118 printf("Received a %s request for %s\nHeaders:\n", 119 cmdtype, evhttp_request_get_uri(req)); 120 121 headers = evhttp_request_get_input_headers(req); 122 for (header = headers->tqh_first; header; 123 header = header->next.tqe_next) { 124 printf(" %s: %s\n", header->key, header->value); 125 } 126 127 buf = evhttp_request_get_input_buffer(req); 128 puts("Input data: <<<"); 129 while (evbuffer_get_length(buf)) { 130 int n; 131 char cbuf[128]; 132 n = evbuffer_remove(buf, cbuf, sizeof(buf)-1); 133 fwrite(cbuf, 1, n, stdout); 134 } 135 puts(">>>"); 136 137 evhttp_send_reply(req, 200, "OK", NULL); 138 } 139 140 /* This callback gets invoked when we get any http request that doesn't match 141 * any other callback. Like any evhttp server callback, it has a simple job: 142 * it must eventually call evhttp_send_error() or evhttp_send_reply(). 143 */ 144 static void 145 send_document_cb(struct evhttp_request *req, void *arg) 146 { 147 struct evbuffer *evb; 148 const char *docroot = arg; 149 const char *uri = evhttp_request_get_uri(req); 150 struct evhttp_uri *decoded = NULL; 151 const char *path; 152 char *decoded_path; 153 char *whole_path = NULL; 154 size_t len; 155 int fd = -1; 156 struct stat st; 157 158 if (evhttp_request_get_command(req) != EVHTTP_REQ_GET) { 159 dump_request_cb(req, arg); 160 return; 161 } 162 163 printf("Got a GET request for <%s>\n", uri); 164 165 /* Decode the URI */ 166 decoded = evhttp_uri_parse(uri); 167 if (!decoded) { 168 printf("It's not a good URI. Sending BADREQUEST\n"); 169 evhttp_send_error(req, HTTP_BADREQUEST, 0); 170 return; 171 } 172 173 /* Let's see what path the user asked for. */ 174 path = evhttp_uri_get_path(decoded); 175 if (!path) path = "/"; 176 177 /* We need to decode it, to see what path the user really wanted. */ 178 decoded_path = evhttp_uridecode(path, 0, NULL); 179 /* Don't allow any ".."s in the path, to avoid exposing stuff outside 180 * of the docroot. This test is both overzealous and underzealous: 181 * it forbids aceptable paths like "/this/one..here", but it doesn't 182 * do anything to prevent symlink following." */ 183 if (strstr(decoded_path, "..")) 184 goto err; 185 186 len = strlen(decoded_path)+strlen(docroot)+2; 187 if (!(whole_path = malloc(len))) { 188 perror("malloc"); 189 goto err; 190 } 191 evutil_snprintf(whole_path, len, "%s/%s", docroot, decoded_path); 192 193 if (stat(whole_path, &st)<0) { 194 goto err; 195 } 196 197 /* This holds the content we're sending. */ 198 evb = evbuffer_new(); 199 200 if (S_ISDIR(st.st_mode)) { 201 /* If it's a directory, read the comments and make a little 202 * index page */ 203 #ifdef WIN32 204 HANDLE d; 205 WIN32_FIND_DATAA ent; 206 char *pattern; 207 size_t dirlen; 208 #else 209 DIR *d; 210 struct dirent *ent; 211 #endif 212 const char *trailing_slash = ""; 213 214 if (!strlen(path) || path[strlen(path)-1] != '/') 215 trailing_slash = "/"; 216 217 #ifdef WIN32 218 dirlen = strlen(whole_path); 219 pattern = malloc(dirlen+3); 220 memcpy(pattern, whole_path, dirlen); 221 pattern[dirlen] = '\\'; 222 pattern[dirlen+1] = '*'; 223 pattern[dirlen+2] = '\0'; 224 d = FindFirstFileA(pattern, &ent); 225 free(pattern); 226 if (d == INVALID_HANDLE_VALUE) 227 goto err; 228 #else 229 if (!(d = opendir(whole_path))) 230 goto err; 231 #endif 232 close(fd); 233 234 evbuffer_add_printf(evb, "<html>\n <head>\n" 235 " <title>%s</title>\n" 236 " <base href='%s%s%s'>\n" 237 " </head>\n" 238 " <body>\n" 239 " <h1>%s</h1>\n" 240 " <ul>\n", 241 decoded_path, /* XXX html-escape this. */ 242 uri_root, path, /* XXX html-escape this? */ 243 trailing_slash, 244 decoded_path /* XXX html-escape this */); 245 #ifdef WIN32 246 do { 247 const char *name = ent.cFileName; 248 #else 249 while ((ent = readdir(d))) { 250 const char *name = ent->d_name; 251 #endif 252 evbuffer_add_printf(evb, 253 " <li><a href=\"%s\">%s</a>\n", 254 name, name);/* XXX escape this */ 255 #ifdef WIN32 256 } while (FindNextFileA(d, &ent)); 257 #else 258 } 259 #endif 260 evbuffer_add_printf(evb, "</ul></body></html>\n"); 261 #ifdef WIN32 262 CloseHandle(d); 263 #else 264 closedir(d); 265 #endif 266 evhttp_add_header(evhttp_request_get_output_headers(req), 267 "Content-Type", "text/html"); 268 } else { 269 /* Otherwise it's a file; add it to the buffer to get 270 * sent via sendfile */ 271 const char *type = guess_content_type(decoded_path); 272 if ((fd = open(whole_path, O_RDONLY)) < 0) { 273 perror("open"); 274 goto err; 275 } 276 277 if (fstat(fd, &st)<0) { 278 /* Make sure the length still matches, now that we 279 * opened the file :/ */ 280 perror("fstat"); 281 goto err; 282 } 283 evhttp_add_header(evhttp_request_get_output_headers(req), 284 "Content-Type", type); 285 evbuffer_add_file(evb, fd, 0, st.st_size); 286 } 287 288 evhttp_send_reply(req, 200, "OK", evb); 289 evbuffer_free(evb); 290 return; 291 err: 292 evhttp_send_error(req, 404, "Document was not found"); 293 if (fd>=0) 294 close(fd); 295 if (decoded) 296 evhttp_uri_free(decoded); 297 if (decoded_path) 298 free(decoded_path); 299 if (whole_path) 300 free(whole_path); 301 } 302 303 static void 304 syntax(void) 305 { 306 fprintf(stdout, "Syntax: http-server <docroot>\n"); 307 } 308 309 int 310 main(int argc, char **argv) 311 { 312 struct event_base *base; 313 struct evhttp *http; 314 struct evhttp_bound_socket *handle; 315 316 unsigned short port = 0; 317 #ifdef WIN32 318 WSADATA WSAData; 319 WSAStartup(0x101, &WSAData); 320 #else 321 if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) 322 return (1); 323 #endif 324 if (argc < 2) { 325 syntax(); 326 return 1; 327 } 328 329 base = event_base_new(); 330 if (!base) { 331 fprintf(stderr, "Couldn't create an event_base: exiting\n"); 332 return 1; 333 } 334 335 /* Create a new evhttp object to handle requests. */ 336 http = evhttp_new(base); 337 if (!http) { 338 fprintf(stderr, "couldn't create evhttp. Exiting.\n"); 339 return 1; 340 } 341 342 /* The /dump URI will dump all requests to stdout and say 200 ok. */ 343 evhttp_set_cb(http, "/dump", dump_request_cb, NULL); 344 345 /* We want to accept arbitrary requests, so we need to set a "generic" 346 * cb. We can also add callbacks for specific paths. */ 347 evhttp_set_gencb(http, send_document_cb, argv[1]); 348 349 /* Now we tell the evhttp what port to listen on */ 350 handle = evhttp_bind_socket_with_handle(http, "0.0.0.0", port); 351 if (!handle) { 352 fprintf(stderr, "couldn't bind to port %d. Exiting.\n", 353 (int)port); 354 return 1; 355 } 356 357 { 358 /* Extract and display the address we're listening on. */ 359 struct sockaddr_storage ss; 360 evutil_socket_t fd; 361 ev_socklen_t socklen = sizeof(ss); 362 char addrbuf[128]; 363 void *inaddr; 364 const char *addr; 365 int got_port = -1; 366 fd = evhttp_bound_socket_get_fd(handle); 367 memset(&ss, 0, sizeof(ss)); 368 if (getsockname(fd, (struct sockaddr *)&ss, &socklen)) { 369 perror("getsockname() failed"); 370 return 1; 371 } 372 if (ss.ss_family == AF_INET) { 373 got_port = ntohs(((struct sockaddr_in*)&ss)->sin_port); 374 inaddr = &((struct sockaddr_in*)&ss)->sin_addr; 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 } else { 379 fprintf(stderr, "Weird address family %d\n", 380 ss.ss_family); 381 return 1; 382 } 383 addr = evutil_inet_ntop(ss.ss_family, inaddr, addrbuf, 384 sizeof(addrbuf)); 385 if (addr) { 386 printf("Listening on %s:%d\n", addr, got_port); 387 evutil_snprintf(uri_root, sizeof(uri_root), 388 "http://%s:%d",addr,got_port); 389 } else { 390 fprintf(stderr, "evutil_inet_ntop failed\n"); 391 return 1; 392 } 393 } 394 395 event_base_dispatch(base); 396 397 return 0; 398 } 399