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 /* Compatibility for possible missing IPv6 declarations */ 10 #include "../util-internal.h" 11 12 #include <stdio.h> 13 #include <stdlib.h> 14 #include <string.h> 15 16 #include <sys/types.h> 17 #include <sys/stat.h> 18 19 #ifdef _WIN32 20 #include <winsock2.h> 21 #include <ws2tcpip.h> 22 #include <windows.h> 23 #include <io.h> 24 #include <fcntl.h> 25 #ifndef S_ISDIR 26 #define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR) 27 #endif 28 #else 29 #include <sys/stat.h> 30 #include <sys/socket.h> 31 #include <signal.h> 32 #include <fcntl.h> 33 #include <unistd.h> 34 #include <dirent.h> 35 #endif 36 37 #include <event2/event.h> 38 #include <event2/http.h> 39 #include <event2/buffer.h> 40 #include <event2/util.h> 41 #include <event2/keyvalq_struct.h> 42 43 #ifdef EVENT__HAVE_NETINET_IN_H 44 #include <netinet/in.h> 45 # ifdef _XOPEN_SOURCE_EXTENDED 46 # include <arpa/inet.h> 47 # endif 48 #endif 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 } 406