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 <signal.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <syslog.h>
32 #include <tls.h>
33 #include <unistd.h>
34 
35 #include "config.h"
36 
37 #ifndef INFTIM
38 # define INFTIM -1
39 #endif
40 
41 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
42 
43 #define SUCCESS		20
44 #define TEMP_REDIRECT	30
45 #define TEMP_FAILURE	40
46 #define CGI_ERROR	42
47 #define NOT_FOUND	51
48 #define PROXY_REFUSED	53
49 #define BAD_REQUEST	59
50 
51 #define MAX_USERS	64
52 
53 #define HOSTSLEN	64
54 #define LOCLEN		32
55 
56 /* maximum hostname and label length, +1 for the NUL-terminator */
57 #define DOMAIN_NAME_LEN	(253+1)
58 #define LABEL_LEN	(63+1)
59 
60 #define LOGE(c, fmt, ...) logs(LOG_ERR,     c, fmt, __VA_ARGS__)
61 #define LOGW(c, fmt, ...) logs(LOG_WARNING, c, fmt, __VA_ARGS__)
62 #define LOGN(c, fmt, ...) logs(LOG_NOTICE,  c, fmt, __VA_ARGS__)
63 #define LOGI(c, fmt, ...) logs(LOG_INFO,    c, fmt, __VA_ARGS__)
64 #define LOGD(c, fmt, ...) logs(LOG_DEBUG,   c, fmt, __VA_ARGS__)
65 
66 struct location {
67 	const char	*match;
68 	const char	*lang;
69 	const char	*default_mime;
70 	const char	*index;
71 	int		 auto_index; /* 0 auto, -1 off, 1 on */
72 	int		 block_code;
73 	const char	*block_fmt;
74 	int		 strip;
75 };
76 
77 struct vhost {
78 	const char	*domain;
79 	const char	*cert;
80 	const char	*key;
81 	const char	*dir;
82 	const char	*cgi;
83 	int		 dirfd;
84 
85 	/* the first location rule is always '*' and holds the default
86 	 * settings for the vhost, from locations[1] onwards there are
87 	 * the "real" location rules specified in the configuration. */
88 	struct location	 locations[LOCLEN];
89 };
90 
91 extern struct vhost hosts[HOSTSLEN];
92 
93 struct etm {			/* extension to mime */
94 	const char	*mime;
95 	const char	*ext;
96 };
97 
98 struct mime {
99 	struct etm	*t;
100 	size_t		len;
101 	size_t		cap;
102 };
103 
104 struct conf {
105 	int		 port;
106 	int		 ipv6;
107 	uint32_t	 protos;
108 	struct mime	 mime;
109 	char		*chroot;
110 	char		*user;
111 };
112 
113 extern struct conf conf;
114 extern int exfd;
115 
116 extern volatile sig_atomic_t hupped;
117 
118 struct iri {
119 	char		*schema;
120 	char		*host;
121 	char		*port;
122 	uint16_t	 port_no;
123 	char		*path;
124 	char		*query;
125 	char		*fragment;
126 };
127 
128 struct parser {
129 	char		*iri;
130 	struct iri	*parsed;
131 	const char	*err;
132 };
133 
134 struct client;
135 
136 typedef void (*statefn)(struct pollfd*, struct client*);
137 
138 /*
139  * DFA: handle_handshake is the initial state, close_conn the final.
140  * Sometimes we have an enter_* function to handle the state switch.
141  *
142  * handle_handshake -> handle_open_conn
143  * handle_handshake -> close_conn		// on err
144  *
145  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
146  * handle_open_conn -> handle_dirlist		// ...same
147  * handle_open_conn -> send_file		// ...same
148  * handle_open_conn -> start_reply		// on error
149  *
150  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
151  * handle_cgi_reply -> start_reply	// on error
152  *
153  * handle_cgi -> close_conn
154  *
155  * handle_dirlist -> send_directory_listing
156  * handle_dirlist -> close_conn			// on error
157  *
158  * send_directory_listing -> close_conn
159  *
160  * send_file -> close_conn
161  */
162 struct client {
163 	struct tls	*ctx;
164 	char		 req[GEMINI_URL_LEN];
165 	struct iri	 iri;
166 	char		 domain[DOMAIN_NAME_LEN];
167 	statefn		 state, next;
168 	int		 code;
169 	const char	*meta;
170 	int		 fd, waiting_on_child;
171 	char		 sbuf[1024];	  /* static buffer */
172 	void		*buf, *i;	  /* mmap buffer */
173 	ssize_t		 len, off;	  /* mmap/static buffer  */
174 	DIR		*dir;
175 	struct sockaddr_storage	 addr;
176 	struct vhost	*host;	/* host she's talking to */
177 };
178 
179 enum {
180 	FILE_EXISTS,
181 	FILE_EXECUTABLE,
182 	FILE_DIRECTORY,
183 	FILE_MISSING,
184 };
185 
186 /* gmid.c */
187 __attribute__((format (printf, 1, 2)))
188 __attribute__((__noreturn__))
189 void fatal(const char*, ...);
190 
191 __attribute__((format (printf, 3, 4)))
192 void logs(int, struct client*, const char*, ...);
193 void log_request(struct client*, char*, size_t);
194 
195 void		 sig_handler(int);
196 void		 gen_certificate(const char*, const char*, const char*);
197 void		 mkdirs(const char*);
198 char		*data_dir(void);
199 void		 load_local_cert(const char*, const char*);
200 void		 load_vhosts(void);
201 int		 make_socket(int, int);
202 void		 setup_tls(void);
203 void		 init_config(void);
204 void		 free_config(void);
205 void		 drop_priv(void);
206 void		 usage(const char*);
207 
208 /* provided by lex/yacc */
209 extern FILE *yyin;
210 extern int yylineno;
211 extern int yyparse(void);
212 extern int yylex(void);
213 
214 void		 yyerror(const char*, ...);
215 int		 parse_portno(const char*);
216 void		 parse_conf(const char*);
217 
218 /* mime.c */
219 void		 init_mime(struct mime*);
220 void		 add_mime(struct mime*, const char*, const char*);
221 void		 load_default_mime(struct mime*);
222 const char	*mime(struct vhost*, const char*);
223 
224 /* server.c */
225 const char	*vhost_lang(struct vhost*, const char*);
226 const char	*vhost_default_mime(struct vhost*, const char*);
227 const char	*vhost_index(struct vhost*, const char*);
228 int		 vhost_auto_index(struct vhost*, const char*);
229 int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
230 int		 vhost_strip(struct vhost*, const char*);
231 void		 mark_nonblock(int);
232 void		 loop(struct tls*, int, int);
233 
234 /* ex.c */
235 int		 send_string(int, const char*);
236 int		 recv_string(int, char**);
237 int		 send_iri(int, struct iri*);
238 int		 recv_iri(int, struct iri*);
239 void		 free_recvd_iri(struct iri*);
240 int		 send_vhost(int, struct vhost*);
241 int		 recv_vhost(int, struct vhost**);
242 int		 send_fd(int, int);
243 int		 recv_fd(int);
244 int		 executor_main(void);
245 
246 /* sandbox.c */
247 void		 sandbox(void);
248 
249 /* utf8.c */
250 int		 valid_multibyte_utf8(struct parser*);
251 char		*utf8_nth(char*, size_t);
252 
253 /* iri.c */
254 int		 parse_iri(char*, struct iri*, const char**);
255 int		 trim_req_iri(char*, const char **);
256 int		 serialize_iri(struct iri*, char*, size_t);
257 
258 /* puny.c */
259 int		 puny_decode(const char*, char*, size_t, const char**);
260 
261 /* utils.c */
262 void		 block_signals(void);
263 void		 unblock_signals(void);
264 int		 starts_with(const char*, const char*);
265 int		 ends_with(const char*, const char*);
266 ssize_t		 filesize(int);
267 char		*absolutify_path(const char*);
268 char		*xstrdup(const char*);
269 
270 #endif