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