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
68char uri_root[512];
69
70static 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' */
90static const char *
91guess_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
104not_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 */
110static void
111dump_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 */
158static void
159send_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;
308err:
309	evhttp_send_error(req, 404, "Document was not found");
310	if (fd>=0)
311		close(fd);
312done:
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
323static void
324syntax(void)
325{
326	fprintf(stdout, "Syntax: http-server <docroot>\n");
327}
328
329int
330main(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