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 fwrite(cbuf, 1, n, stdout); 137 } 138 puts(">>>"); 139 140 evhttp_send_reply(req, 200, "OK", NULL); 141 } 142 143 /* This callback gets invoked when we get any http request that doesn't match 144 * any other callback. Like any evhttp server callback, it has a simple job: 145 * it must eventually call evhttp_send_error() or evhttp_send_reply(). 146 */ 147 static void 148 send_document_cb(struct evhttp_request *req, void *arg) 149 { 150 struct evbuffer *evb = NULL; 151 const char *docroot = arg; 152 const char *uri = evhttp_request_get_uri(req); 153 struct evhttp_uri *decoded = NULL; 154 const char *path; 155 char *decoded_path; 156 char *whole_path = NULL; 157 size_t len; 158 int fd = -1; 159 struct stat st; 160 161 if (evhttp_request_get_command(req) != EVHTTP_REQ_GET) { 162 dump_request_cb(req, arg); 163 return; 164 } 165 166 printf("Got a GET request for <%s>\n", uri); 167 168 /* Decode the URI */ 169 decoded = evhttp_uri_parse(uri); 170 if (!decoded) { 171 printf("It's not a good URI. Sending BADREQUEST\n"); 172 evhttp_send_error(req, HTTP_BADREQUEST, 0); 173 return; 174 } 175 176 /* Let's see what path the user asked for. */ 177 path = evhttp_uri_get_path(decoded); 178 if (!path) path = "/"; 179 180 /* We need to decode it, to see what path the user really wanted. */ 181 decoded_path = evhttp_uridecode(path, 0, NULL); 182 /* Don't allow any ".."s in the path, to avoid exposing stuff outside 183 * of the docroot. This test is both overzealous and underzealous: 184 * it forbids aceptable paths like "/this/one..here", but it doesn't 185 * do anything to prevent symlink following." */ 186 if (strstr(decoded_path, "..")) 187 goto err; 188 189 len = strlen(decoded_path)+strlen(docroot)+2; 190 if (!(whole_path = malloc(len))) { 191 perror("malloc"); 192 goto err; 193 } 194 evutil_snprintf(whole_path, len, "%s/%s", docroot, decoded_path); 195 196 if (stat(whole_path, &st)<0) { 197 goto err; 198 } 199 200 /* This holds the content we're sending. */ 201 evb = evbuffer_new(); 202 203 if (S_ISDIR(st.st_mode)) { 204 /* If it's a directory, read the comments and make a little 205 * index page */ 206 #ifdef _WIN32 207 HANDLE d; 208 WIN32_FIND_DATAA ent; 209 char *pattern; 210 size_t dirlen; 211 #else 212 DIR *d; 213 struct dirent *ent; 214 #endif 215 const char *trailing_slash = ""; 216 217 if (!strlen(path) || path[strlen(path)-1] != '/') 218 trailing_slash = "/"; 219 220 #ifdef _WIN32 221 dirlen = strlen(whole_path); 222 pattern = malloc(dirlen+3); 223 memcpy(pattern, whole_path, dirlen); 224 pattern[dirlen] = '\\'; 225 pattern[dirlen+1] = '*'; 226 pattern[dirlen+2] = '\0'; 227 d = FindFirstFileA(pattern, &ent); 228 free(pattern); 229 if (d == INVALID_HANDLE_VALUE) 230 goto err; 231 #else 232 if (!(d = opendir(whole_path))) 233 goto err; 234 #endif 235 236 evbuffer_add_printf(evb, "<html>\n <head>\n" 237 " <title>%s</title>\n" 238 " <base href='%s%s%s'>\n" 239 " </head>\n" 240 " <body>\n" 241 " <h1>%s</h1>\n" 242 " <ul>\n", 243 decoded_path, /* XXX html-escape this. */ 244 uri_root, path, /* XXX html-escape this? */ 245 trailing_slash, 246 decoded_path /* XXX html-escape this */); 247 #ifdef _WIN32 248 do { 249 const char *name = ent.cFileName; 250 #else 251 while ((ent = readdir(d))) { 252 const char *name = ent->d_name; 253 #endif 254 evbuffer_add_printf(evb, 255 " <li><a href=\"%s\">%s</a>\n", 256 name, name);/* XXX escape this */ 257 #ifdef _WIN32 258 } while (FindNextFileA(d, &ent)); 259 #else 260 } 261 #endif 262 evbuffer_add_printf(evb, "</ul></body></html>\n"); 263 #ifdef _WIN32 264 CloseHandle(d); 265 #else 266 closedir(d); 267 #endif 268 evhttp_add_header(evhttp_request_get_output_headers(req), 269 "Content-Type", "text/html"); 270 } else { 271 /* Otherwise it's a file; add it to the buffer to get 272 * sent via sendfile */ 273 const char *type = guess_content_type(decoded_path); 274 if ((fd = open(whole_path, O_RDONLY)) < 0) { 275 perror("open"); 276 goto err; 277 } 278 279 if (fstat(fd, &st)<0) { 280 /* Make sure the length still matches, now that we 281 * opened the file :/ */ 282 perror("fstat"); 283 goto err; 284 } 285 evhttp_add_header(evhttp_request_get_output_headers(req), 286 "Content-Type", type); 287 evbuffer_add_file(evb, fd, 0, st.st_size); 288 } 289 290 evhttp_send_reply(req, 200, "OK", evb); 291 goto done; 292 err: 293 evhttp_send_error(req, 404, "Document was not found"); 294 if (fd>=0) 295 close(fd); 296 done: 297 if (decoded) 298 evhttp_uri_free(decoded); 299 if (decoded_path) 300 free(decoded_path); 301 if (whole_path) 302 free(whole_path); 303 if (evb) 304 evbuffer_free(evb); 305 } 306 307 static void 308 syntax(void) 309 { 310 fprintf(stdout, "Syntax: http-server <docroot>\n"); 311 } 312 313 int 314 main(int argc, char **argv) 315 { 316 struct event_base *base; 317 struct evhttp *http; 318 struct evhttp_bound_socket *handle; 319 320 unsigned short port = 0; 321 #ifdef _WIN32 322 WSADATA WSAData; 323 WSAStartup(0x101, &WSAData); 324 #else 325 if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) 326 return (1); 327 #endif 328 if (argc < 2) { 329 syntax(); 330 return 1; 331 } 332 333 base = event_base_new(); 334 if (!base) { 335 fprintf(stderr, "Couldn't create an event_base: exiting\n"); 336 return 1; 337 } 338 339 /* Create a new evhttp object to handle requests. */ 340 http = evhttp_new(base); 341 if (!http) { 342 fprintf(stderr, "couldn't create evhttp. Exiting.\n"); 343 return 1; 344 } 345 346 /* The /dump URI will dump all requests to stdout and say 200 ok. */ 347 evhttp_set_cb(http, "/dump", dump_request_cb, NULL); 348 349 /* We want to accept arbitrary requests, so we need to set a "generic" 350 * cb. We can also add callbacks for specific paths. */ 351 evhttp_set_gencb(http, send_document_cb, argv[1]); 352 353 /* Now we tell the evhttp what port to listen on */ 354 handle = evhttp_bind_socket_with_handle(http, "0.0.0.0", port); 355 if (!handle) { 356 fprintf(stderr, "couldn't bind to port %d. Exiting.\n", 357 (int)port); 358 return 1; 359 } 360 361 { 362 /* Extract and display the address we're listening on. */ 363 struct sockaddr_storage ss; 364 evutil_socket_t fd; 365 ev_socklen_t socklen = sizeof(ss); 366 char addrbuf[128]; 367 void *inaddr; 368 const char *addr; 369 int got_port = -1; 370 fd = evhttp_bound_socket_get_fd(handle); 371 memset(&ss, 0, sizeof(ss)); 372 if (getsockname(fd, (struct sockaddr *)&ss, &socklen)) { 373 perror("getsockname() failed"); 374 return 1; 375 } 376 if (ss.ss_family == AF_INET) { 377 got_port = ntohs(((struct sockaddr_in*)&ss)->sin_port); 378 inaddr = &((struct sockaddr_in*)&ss)->sin_addr; 379 } else if (ss.ss_family == AF_INET6) { 380 got_port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port); 381 inaddr = &((struct sockaddr_in6*)&ss)->sin6_addr; 382 } else { 383 fprintf(stderr, "Weird address family %d\n", 384 ss.ss_family); 385 return 1; 386 } 387 addr = evutil_inet_ntop(ss.ss_family, inaddr, addrbuf, 388 sizeof(addrbuf)); 389 if (addr) { 390 printf("Listening on %s:%d\n", addr, got_port); 391 evutil_snprintf(uri_root, sizeof(uri_root), 392 "http://%s:%d",addr,got_port); 393 } else { 394 fprintf(stderr, "evutil_inet_ntop failed\n"); 395 return 1; 396 } 397 } 398 399 event_base_dispatch(base); 400 401 return 0; 402 } 403