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 	const char	*entrypoint;
84 	int		 dirfd;
85 
86 	/* the first location rule is always '*' and holds the default
87 	 * settings for the vhost, from locations[1] onwards there are
88 	 * the "real" location rules specified in the configuration. */
89 	struct location	 locations[LOCLEN];
90 };
91 
92 extern struct vhost hosts[HOSTSLEN];
93 
94 struct etm {			/* extension to mime */
95 	const char	*mime;
96 	const char	*ext;
97 };
98 
99 struct mime {
100 	struct etm	*t;
101 	size_t		len;
102 	size_t		cap;
103 };
104 
105 struct conf {
106 	int		 port;
107 	int		 ipv6;
108 	uint32_t	 protos;
109 	struct mime	 mime;
110 	char		*chroot;
111 	char		*user;
112 };
113 
114 extern struct conf conf;
115 extern int exfd;
116 
117 extern volatile sig_atomic_t hupped;
118 
119 struct iri {
120 	char		*schema;
121 	char		*host;
122 	char		*port;
123 	uint16_t	 port_no;
124 	char		*path;
125 	char		*query;
126 	char		*fragment;
127 };
128 
129 struct parser {
130 	char		*iri;
131 	struct iri	*parsed;
132 	const char	*err;
133 };
134 
135 struct client;
136 
137 typedef void (*statefn)(struct pollfd*, struct client*);
138 
139 /*
140  * DFA: handle_handshake is the initial state, close_conn the final.
141  * Sometimes we have an enter_* function to handle the state switch.
142  *
143  * handle_handshake -> handle_open_conn
144  * handle_handshake -> close_conn		// on err
145  *
146  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
147  * handle_open_conn -> handle_dirlist		// ...same
148  * handle_open_conn -> send_file		// ...same
149  * handle_open_conn -> start_reply		// on error
150  *
151  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
152  * handle_cgi_reply -> start_reply	// on error
153  *
154  * handle_cgi -> close_conn
155  *
156  * handle_dirlist -> send_directory_listing
157  * handle_dirlist -> close_conn			// on error
158  *
159  * send_directory_listing -> close_conn
160  *
161  * send_file -> close_conn
162  */
163 struct client {
164 	struct tls	*ctx;
165 	char		 req[GEMINI_URL_LEN];
166 	struct iri	 iri;
167 	char		 domain[DOMAIN_NAME_LEN];
168 	statefn		 state, next;
169 	int		 code;
170 	const char	*meta;
171 	int		 fd, waiting_on_child;
172 	char		 sbuf[1024];	  /* static buffer */
173 	void		*buf, *i;	  /* mmap buffer */
174 	ssize_t		 len, off;	  /* mmap/static buffer  */
175 	DIR		*dir;
176 	struct sockaddr_storage	 addr;
177 	struct vhost	*host;	/* host she's talking to */
178 };
179 
180 enum {
181 	FILE_EXISTS,
182 	FILE_EXECUTABLE,
183 	FILE_DIRECTORY,
184 	FILE_MISSING,
185 };
186 
187 /* gmid.c */
188 __attribute__((format (printf, 1, 2)))
189 __attribute__((__noreturn__))
190 void fatal(const char*, ...);
191 
192 __attribute__((format (printf, 3, 4)))
193 void logs(int, struct client*, const char*, ...);
194 void log_request(struct client*, char*, size_t);
195 
196 void		 sig_handler(int);
197 void		 gen_certificate(const char*, const char*, const char*);
198 void		 mkdirs(const char*);
199 char		*data_dir(void);
200 void		 load_local_cert(const char*, const char*);
201 void		 load_vhosts(void);
202 int		 make_socket(int, int);
203 void		 setup_tls(void);
204 void		 init_config(void);
205 void		 free_config(void);
206 void		 drop_priv(void);
207 void		 usage(const char*);
208 
209 /* provided by lex/yacc */
210 extern FILE *yyin;
211 extern int yylineno;
212 extern int yyparse(void);
213 extern int yylex(void);
214 
215 void		 yyerror(const char*, ...);
216 int		 parse_portno(const char*);
217 void		 parse_conf(const char*);
218 
219 /* mime.c */
220 void		 init_mime(struct mime*);
221 void		 add_mime(struct mime*, const char*, const char*);
222 void		 load_default_mime(struct mime*);
223 const char	*mime(struct vhost*, const char*);
224 
225 /* server.c */
226 const char	*vhost_lang(struct vhost*, const char*);
227 const char	*vhost_default_mime(struct vhost*, const char*);
228 const char	*vhost_index(struct vhost*, const char*);
229 int		 vhost_auto_index(struct vhost*, const char*);
230 int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
231 int		 vhost_strip(struct vhost*, const char*);
232 void		 mark_nonblock(int);
233 void		 loop(struct tls*, int, int);
234 
235 /* ex.c */
236 int		 send_string(int, const char*);
237 int		 recv_string(int, char**);
238 int		 send_iri(int, struct iri*);
239 int		 recv_iri(int, struct iri*);
240 void		 free_recvd_iri(struct iri*);
241 int		 send_vhost(int, struct vhost*);
242 int		 recv_vhost(int, struct vhost**);
243 int		 send_fd(int, int);
244 int		 recv_fd(int);
245 int		 executor_main(void);
246 
247 /* sandbox.c */
248 void		 sandbox(void);
249 
250 /* utf8.c */
251 int		 valid_multibyte_utf8(struct parser*);
252 char		*utf8_nth(char*, size_t);
253 
254 /* iri.c */
255 int		 parse_iri(char*, struct iri*, const char**);
256 int		 trim_req_iri(char*, const char **);
257 int		 serialize_iri(struct iri*, char*, size_t);
258 
259 /* puny.c */
260 int		 puny_decode(const char*, char*, size_t, const char**);
261 
262 /* utils.c */
263 void		 block_signals(void);
264 void		 unblock_signals(void);
265 int		 starts_with(const char*, const char*);
266 int		 ends_with(const char*, const char*);
267 ssize_t		 filesize(int);
268 char		*absolutify_path(const char*);
269 char		*xstrdup(const char*);
270 
271 #endif