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 #ifndef stat
52 #define stat _stat
53 #endif
54 #ifndef fstat
55 #define fstat _fstat
56 #endif
57 #ifndef open
58 #define open _open
59 #endif
60 #ifndef close
61 #define close _close
62 #endif
63 #ifndef O_RDONLY
64 #define O_RDONLY _O_RDONLY
65 #endif
66 #endif
67
68 char uri_root[512];
69
70 static const struct table_entry {
71 const char *extension;
72 const char *content_type;
73 } content_type_table[] = {
74 { "txt", "text/plain" },
75 { "c", "text/plain" },
76 { "h", "text/plain" },
77 { "html", "text/html" },
78 { "htm", "text/htm" },
79 { "css", "text/css" },
80 { "gif", "image/gif" },
81 { "jpg", "image/jpeg" },
82 { "jpeg", "image/jpeg" },
83 { "png", "image/png" },
84 { "pdf", "application/pdf" },
85 { "ps", "application/postscript" },
86 { NULL, NULL },
87 };
88
89 /* Try to guess a good content-type for 'path' */
90 static const char *
guess_content_type(const char * path)91 guess_content_type(const char *path)
92 {
93 const char *last_period, *extension;
94 const struct table_entry *ent;
95 last_period = strrchr(path, '.');
96 if (!last_period || strchr(last_period, '/'))
97 goto not_found; /* no exension */
98 extension = last_period + 1;
99 for (ent = &content_type_table[0]; ent->extension; ++ent) {
100 if (!evutil_ascii_strcasecmp(ent->extension, extension))
101 return ent->content_type;
102 }
103
104 not_found:
105 return "application/misc";
106 }
107
108 /* Callback used for the /dump URI, and for every non-GET request:
109 * dumps all information to stdout and gives back a trivial 200 ok */
110 static void
dump_request_cb(struct evhttp_request * req,void * arg)111 dump_request_cb(struct evhttp_request *req, void *arg)
112 {
113 const char *cmdtype;
114 struct evkeyvalq *headers;
115 struct evkeyval *header;
116 struct evbuffer *buf;
117
118 switch (evhttp_request_get_command(req)) {
119 case EVHTTP_REQ_GET: cmdtype = "GET"; break;
120 case EVHTTP_REQ_POST: cmdtype = "POST"; break;
121 case EVHTTP_REQ_HEAD: cmdtype = "HEAD"; break;
122 case EVHTTP_REQ_PUT: cmdtype = "PUT"; break;
123 case EVHTTP_REQ_DELETE: cmdtype = "DELETE"; break;
124 case EVHTTP_REQ_OPTIONS: cmdtype = "OPTIONS"; break;
125 case EVHTTP_REQ_TRACE: cmdtype = "TRACE"; break;
126 case EVHTTP_REQ_CONNECT: cmdtype = "CONNECT"; break;
127 case EVHTTP_REQ_PATCH: cmdtype = "PATCH"; break;
128 default: cmdtype = "unknown"; break;
129 }
130
131 printf("Received a %s request for %s\nHeaders:\n",
132 cmdtype, evhttp_request_get_uri(req));
133
134 headers = evhttp_request_get_input_headers(req);
135 for (header = headers->tqh_first; header;
136 header = header->next.tqe_next) {
137 printf(" %s: %s\n", header->key, header->value);
138 }
139
140 buf = evhttp_request_get_input_buffer(req);
141 puts("Input data: <<<");
142 while (evbuffer_get_length(buf)) {
143 int n;
144 char cbuf[128];
145 n = evbuffer_remove(buf, cbuf, sizeof(cbuf));
146 if (n > 0)
147 (void) fwrite(cbuf, 1, n, stdout);
148 }
149 puts(">>>");
150
151 evhttp_send_reply(req, 200, "OK", NULL);
152 }
153
154 /* This callback gets invoked when we get any http request that doesn't match
155 * any other callback. Like any evhttp server callback, it has a simple job:
156 * it must eventually call evhttp_send_error() or evhttp_send_reply().
157 */
158 static void
send_document_cb(struct evhttp_request * req,void * arg)159 send_document_cb(struct evhttp_request *req, void *arg)
160 {
161 struct evbuffer *evb = NULL;
162 const char *docroot = arg;
163 const char *uri = evhttp_request_get_uri(req);
164 struct evhttp_uri *decoded = NULL;
165 const char *path;
166 char *decoded_path;
167 char *whole_path = NULL;
168 size_t len;
169 int fd = -1;
170 struct stat st;
171
172 if (evhttp_request_get_command(req) != EVHTTP_REQ_GET) {
173 dump_request_cb(req, arg);
174 return;
175 }
176
177 printf("Got a GET request for <%s>\n", uri);
178
179 /* Decode the URI */
180 decoded = evhttp_uri_parse(uri);
181 if (!decoded) {
182 printf("It's not a good URI. Sending BADREQUEST\n");
183 evhttp_send_error(req, HTTP_BADREQUEST, 0);
184 return;
185 }
186
187 /* Let's see what path the user asked for. */
188 path = evhttp_uri_get_path(decoded);
189 if (!path) path = "/";
190
191 /* We need to decode it, to see what path the user really wanted. */
192 decoded_path = evhttp_uridecode(path, 0, NULL);
193 if (decoded_path == NULL)
194 goto err;
195 /* Don't allow any ".."s in the path, to avoid exposing stuff outside
196 * of the docroot. This test is both overzealous and underzealous:
197 * it forbids aceptable paths like "/this/one..here", but it doesn't
198 * do anything to prevent symlink following." */
199 if (strstr(decoded_path, ".."))
200 goto err;
201
202 len = strlen(decoded_path)+strlen(docroot)+2;
203 if (!(whole_path = malloc(len))) {
204 perror("malloc");
205 goto err;
206 }
207 evutil_snprintf(whole_path, len, "%s/%s", docroot, decoded_path);
208
209 if (stat(whole_path, &st)<0) {
210 goto err;
211 }
212
213 /* This holds the content we're sending. */
214 evb = evbuffer_new();
215
216 if (S_ISDIR(st.st_mode)) {
217 /* If it's a directory, read the comments and make a little
218 * index page */
219 #ifdef _WIN32
220 HANDLE d;
221 WIN32_FIND_DATAA ent;
222 char *pattern;
223 size_t dirlen;
224 #else
225 DIR *d;
226 struct dirent *ent;
227 #endif
228 const char *trailing_slash = "";
229
230 if (!strlen(path) || path[strlen(path)-1] != '/')
231 trailing_slash = "/";
232
233 #ifdef _WIN32
234 dirlen = strlen(whole_path);
235 pattern = malloc(dirlen+3);
236 memcpy(pattern, whole_path, dirlen);
237 pattern[dirlen] = '\\';
238 pattern[dirlen+1] = '*';
239 pattern[dirlen+2] = '\0';
240 d = FindFirstFileA(pattern, &ent);
241 free(pattern);
242 if (d == INVALID_HANDLE_VALUE)
243 goto err;
244 #else
245 if (!(d = opendir(whole_path)))
246 goto err;
247 #endif
248
249 evbuffer_add_printf(evb,
250 "<!DOCTYPE html>\n"
251 "<html>\n <head>\n"
252 " <meta charset='utf-8'>\n"
253 " <title>%s</title>\n"
254 " <base href='%s%s'>\n"
255 " </head>\n"
256 " <body>\n"
257 " <h1>%s</h1>\n"
258 " <ul>\n",
259 decoded_path, /* XXX html-escape this. */
260 path, /* XXX html-escape this? */
261 trailing_slash,
262 decoded_path /* XXX html-escape this */);
263 #ifdef _WIN32
264 do {
265 const char *name = ent.cFileName;
266 #else
267 while ((ent = readdir(d))) {
268 const char *name = ent->d_name;
269 #endif
270 evbuffer_add_printf(evb,
271 " <li><a href=\"%s\">%s</a>\n",
272 name, name);/* XXX escape this */
273 #ifdef _WIN32
274 } while (FindNextFileA(d, &ent));
275 #else
276 }
277 #endif
278 evbuffer_add_printf(evb, "</ul></body></html>\n");
279 #ifdef _WIN32
280 FindClose(d);
281 #else
282 closedir(d);
283 #endif
284 evhttp_add_header(evhttp_request_get_output_headers(req),
285 "Content-Type", "text/html");
286 } else {
287 /* Otherwise it's a file; add it to the buffer to get
288 * sent via sendfile */
289 const char *type = guess_content_type(decoded_path);
290 if ((fd = open(whole_path, O_RDONLY)) < 0) {
291 perror("open");
292 goto err;
293 }
294
295 if (fstat(fd, &st)<0) {
296 /* Make sure the length still matches, now that we
297 * opened the file :/ */
298 perror("fstat");
299 goto err;
300 }
301 evhttp_add_header(evhttp_request_get_output_headers(req),
302 "Content-Type", type);
303 evbuffer_add_file(evb, fd, 0, st.st_size);
304 }
305
306 evhttp_send_reply(req, 200, "OK", evb);
307 goto done;
308 err:
309 evhttp_send_error(req, 404, "Document was not found");
310 if (fd>=0)
311 close(fd);
312 done:
313 if (decoded)
314 evhttp_uri_free(decoded);
315 if (decoded_path)
316 free(decoded_path);
317 if (whole_path)
318 free(whole_path);
319 if (evb)
320 evbuffer_free(evb);
321 }
322
323 static void
syntax(void)324 syntax(void)
325 {
326 fprintf(stdout, "Syntax: http-server <docroot>\n");
327 }
328
329 int
main(int argc,char ** argv)330 main(int argc, char **argv)
331 {
332 struct event_base *base;
333 struct evhttp *http;
334 struct evhttp_bound_socket *handle;
335
336 ev_uint16_t port = 0;
337 #ifdef _WIN32
338 WSADATA WSAData;
339 WSAStartup(0x101, &WSAData);
340 #else
341 if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
342 return (1);
343 #endif
344 if (argc < 2) {
345 syntax();
346 return 1;
347 }
348
349 base = event_base_new();
350 if (!base) {
351 fprintf(stderr, "Couldn't create an event_base: exiting\n");
352 return 1;
353 }
354
355 /* Create a new evhttp object to handle requests. */
356 http = evhttp_new(base);
357 if (!http) {
358 fprintf(stderr, "couldn't create evhttp. Exiting.\n");
359 return 1;
360 }
361
362 /* The /dump URI will dump all requests to stdout and say 200 ok. */
363 evhttp_set_cb(http, "/dump", dump_request_cb, NULL);
364
365 /* We want to accept arbitrary requests, so we need to set a "generic"
366 * cb. We can also add callbacks for specific paths. */
367 evhttp_set_gencb(http, send_document_cb, argv[1]);
368
369 /* Now we tell the evhttp what port to listen on */
370 handle = evhttp_bind_socket_with_handle(http, "0.0.0.0", port);
371 if (!handle) {
372 fprintf(stderr, "couldn't bind to port %d. Exiting.\n",
373 (int)port);
374 return 1;
375 }
376
377 {
378 /* Extract and display the address we're listening on. */
379 struct sockaddr_storage ss;
380 evutil_socket_t fd;
381 ev_socklen_t socklen = sizeof(ss);
382 char addrbuf[128];
383 void *inaddr;
384 const char *addr;
385 int got_port = -1;
386 fd = evhttp_bound_socket_get_fd(handle);
387 memset(&ss, 0, sizeof(ss));
388 if (getsockname(fd, (struct sockaddr *)&ss, &socklen)) {
389 perror("getsockname() failed");
390 return 1;
391 }
392 if (ss.ss_family == AF_INET) {
393 got_port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
394 inaddr = &((struct sockaddr_in*)&ss)->sin_addr;
395 } else if (ss.ss_family == AF_INET6) {
396 got_port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
397 inaddr = &((struct sockaddr_in6*)&ss)->sin6_addr;
398 } else {
399 fprintf(stderr, "Weird address family %d\n",
400 ss.ss_family);
401 return 1;
402 }
403 addr = evutil_inet_ntop(ss.ss_family, inaddr, addrbuf,
404 sizeof(addrbuf));
405 if (addr) {
406 printf("Listening on %s:%d\n", addr, got_port);
407 evutil_snprintf(uri_root, sizeof(uri_root),
408 "http://%s:%d",addr,got_port);
409 } else {
410 fprintf(stderr, "evutil_inet_ntop failed\n");
411 return 1;
412 }
413 }
414
415 event_base_dispatch(base);
416
417 return 0;
418 }
419