1 /*
2  * Copyright (c) 2020 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #ifndef GMID_H
18 #define GMID_H
19 
20 #include <sys/socket.h>
21 #include <sys/types.h>
22 
23 #include <arpa/inet.h>
24 #include <netinet/in.h>
25 
26 #include <dirent.h>
27 #include <poll.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <syslog.h>
31 #include <tls.h>
32 #include <unistd.h>
33 
34 #include "config.h"
35 
36 #ifndef INFTIM
37 # define INFTIM -1
38 #endif
39 
40 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
41 
42 #define SUCCESS		20
43 #define TEMP_REDIRECT	30
44 #define TEMP_FAILURE	40
45 #define CGI_ERROR	42
46 #define NOT_FOUND	51
47 #define PROXY_REFUSED	53
48 #define BAD_REQUEST	59
49 
50 #define MAX_USERS	64
51 
52 #define HOSTSLEN	64
53 #define LOCLEN		32
54 
55 /* maximum hostname and label length, +1 for the NUL-terminator */
56 #define DOMAIN_NAME_LEN	(253+1)
57 #define LABEL_LEN	(63+1)
58 
59 #define LOGE(c, fmt, ...) logs(LOG_ERR,     c, fmt, __VA_ARGS__)
60 #define LOGW(c, fmt, ...) logs(LOG_WARNING, c, fmt, __VA_ARGS__)
61 #define LOGN(c, fmt, ...) logs(LOG_NOTICE,  c, fmt, __VA_ARGS__)
62 #define LOGI(c, fmt, ...) logs(LOG_INFO,    c, fmt, __VA_ARGS__)
63 #define LOGD(c, fmt, ...) logs(LOG_DEBUG,   c, fmt, __VA_ARGS__)
64 
65 struct location {
66 	const char	*match;
67 	const char	*lang;
68 	const char	*default_mime;
69 	const char	*index;
70 	int		 auto_index; /* 0 auto, -1 off, 1 on */
71 };
72 
73 struct vhost {
74 	const char	*domain;
75 	const char	*cert;
76 	const char	*key;
77 	const char	*dir;
78 	const char	*cgi;
79 	int		 dirfd;
80 
81 	/* the first location rule is always '*' and holds the default
82 	 * settings for the vhost, from locations[1] onwards there are
83 	 * the "real" location rules specified in the configuration. */
84 	struct location	 locations[LOCLEN];
85 };
86 
87 extern struct vhost hosts[HOSTSLEN];
88 
89 struct etm {			/* extension to mime */
90 	const char	*mime;
91 	const char	*ext;
92 };
93 
94 struct mime {
95 	struct etm	*t;
96 	size_t		len;
97 	size_t		cap;
98 };
99 
100 struct conf {
101 	int		 port;
102 	int		 ipv6;
103 	uint32_t	 protos;
104 	struct mime	 mime;
105 	char		*chroot;
106 	char		*user;
107 };
108 
109 extern struct conf conf;
110 extern int exfd;
111 
112 struct iri {
113 	char		*schema;
114 	char		*host;
115 	char		*port;
116 	uint16_t	 port_no;
117 	char		*path;
118 	char		*query;
119 	char		*fragment;
120 };
121 
122 struct parser {
123 	char		*iri;
124 	struct iri	*parsed;
125 	const char	*err;
126 };
127 
128 struct client;
129 
130 typedef void (*statefn)(struct pollfd*, struct client*);
131 
132 /*
133  * DFA: handle_handshake is the initial state, close_conn the final.
134  * Sometimes we have an enter_* function to handle the state switch.
135  *
136  * handle_handshake -> handle_open_conn
137  * handle_handshake -> close_conn		// on err
138  *
139  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
140  * handle_open_conn -> handle_dirlist		// ...same
141  * handle_open_conn -> send_file		// ...same
142  * handle_open_conn -> start_reply		// on error
143  *
144  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
145  * handle_cgi_reply -> start_reply	// on error
146  *
147  * handle_cgi -> close_conn
148  *
149  * handle_dirlist -> send_directory_listing
150  * handle_dirlist -> close_conn			// on error
151  *
152  * send_directory_listing -> close_conn
153  *
154  * send_file -> close_conn
155  */
156 struct client {
157 	struct tls	*ctx;
158 	char		 req[GEMINI_URL_LEN];
159 	struct iri	 iri;
160 	char		 domain[DOMAIN_NAME_LEN];
161 	statefn		 state, next;
162 	int		 code;
163 	const char	*meta;
164 	int		 fd, waiting_on_child;
165 	char		 sbuf[1024];	  /* static buffer */
166 	void		*buf, *i;	  /* mmap buffer */
167 	ssize_t		 len, off;	  /* mmap/static buffer  */
168 	DIR		*dir;
169 	struct sockaddr_storage	 addr;
170 	struct vhost	*host;	/* host she's talking to */
171 };
172 
173 enum {
174 	FILE_EXISTS,
175 	FILE_EXECUTABLE,
176 	FILE_DIRECTORY,
177 	FILE_MISSING,
178 };
179 
180 /* gmid.c */
181 __attribute__((format (printf, 1, 2)))
182 __attribute__((__noreturn__))
183 void fatal(const char*, ...);
184 
185 __attribute__((format (printf, 3, 4)))
186 void logs(int, struct client*, const char*, ...);
187 void log_request(struct client*, char*, size_t);
188 
189 void		 sig_handler(int);
190 void		 gen_certificate(const char*, const char*, const char*);
191 void		 mkdirs(const char*);
192 char		*data_dir(void);
193 void		 load_local_cert(const char*, const char*);
194 void		 load_vhosts(void);
195 int		 make_socket(int, int);
196 void		 setup_tls(void);
197 int		 listener_main(void);
198 void		 init_config(void);
199 void		 drop_priv(void);
200 void		 usage(const char*);
201 
202 /* provided by lex/yacc */
203 extern FILE *yyin;
204 extern int yylineno;
205 extern int yyparse(void);
206 extern int yylex(void);
207 
208 void		 yyerror(const char*);
209 int		 parse_portno(const char*);
210 void		 parse_conf(const char*);
211 
212 /* mime.c */
213 void		 init_mime(struct mime*);
214 void		 add_mime(struct mime*, const char*, const char*);
215 void		 load_default_mime(struct mime*);
216 const char	*mime(struct vhost*, const char*);
217 
218 /* server.c */
219 const char	*vhost_lang(struct vhost*, const char*);
220 const char	*vhost_default_mime(struct vhost*, const char*);
221 const char	*vhost_index(struct vhost*, const char*);
222 int		 vhost_auto_index(struct vhost*, const char*);
223 int		 check_path(struct client*, const char*, int*);
224 void		 open_file(struct pollfd*, struct client*);
225 void		 load_file(struct pollfd*, struct client*);
226 void		 check_for_cgi(struct pollfd*, struct client*);
227 void		 mark_nonblock(int);
228 void		 handle_handshake(struct pollfd*, struct client*);
229 void		 handle_open_conn(struct pollfd*, struct client*);
230 void		 start_reply(struct pollfd*, struct client*, int, const char*);
231 void		 handle_start_reply(struct pollfd*, struct client*);
232 void		 start_cgi(const char*, const char*, struct pollfd*, struct client*);
233 void		 send_file(struct pollfd*, struct client*);
234 void		 open_dir(struct pollfd*, struct client*);
235 void		 redirect_canonical_dir(struct pollfd*, struct client*);
236 void		 enter_handle_dirlist(struct pollfd*, struct client*);
237 void		 handle_dirlist(struct pollfd*, struct client*);
238 int		 read_next_dir_entry(struct client*);
239 void		 send_directory_listing(struct pollfd*, struct client*);
240 void		 cgi_poll_on_child(struct pollfd*, struct client*);
241 void		 cgi_poll_on_client(struct pollfd*, struct client*);
242 void		 handle_cgi_reply(struct pollfd*, struct client*);
243 void		 handle_cgi(struct pollfd*, struct client*);
244 void		 close_conn(struct pollfd*, struct client*);
245 void		 do_accept(int, struct tls*, struct pollfd*, struct client*);
246 void		 loop(struct tls*, int, int);
247 
248 /* ex.c */
249 int		 send_string(int, const char*);
250 int		 recv_string(int, char**);
251 int		 send_iri(int, struct iri*);
252 int		 recv_iri(int, struct iri*);
253 void		 free_recvd_iri(struct iri*);
254 int		 send_vhost(int, struct vhost*);
255 int		 recv_vhost(int, struct vhost**);
256 int		 send_fd(int, int);
257 int		 recv_fd(int);
258 int		 executor_main(int);
259 
260 /* sandbox.c */
261 void		 sandbox(void);
262 
263 /* utf8.c */
264 int		 valid_multibyte_utf8(struct parser*);
265 char		*utf8_nth(char*, size_t);
266 
267 /* iri.c */
268 int		 parse_iri(char*, struct iri*, const char**);
269 int		 trim_req_iri(char*, const char **);
270 int		 serialize_iri(struct iri*, char*, size_t);
271 
272 /* puny.c */
273 int		 puny_decode(const char*, char*, size_t, const char**);
274 
275 /* utils.c */
276 int		 starts_with(const char*, const char*);
277 int		 ends_with(const char*, const char*);
278 ssize_t		 filesize(int);
279 char		*absolutify_path(const char*);
280 
281 #endif