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 };
73 
74 struct vhost {
75 	const char	*domain;
76 	const char	*cert;
77 	const char	*key;
78 	const char	*dir;
79 	const char	*cgi;
80 	int		 dirfd;
81 
82 	/* the first location rule is always '*' and holds the default
83 	 * settings for the vhost, from locations[1] onwards there are
84 	 * the "real" location rules specified in the configuration. */
85 	struct location	 locations[LOCLEN];
86 };
87 
88 extern struct vhost hosts[HOSTSLEN];
89 
90 struct etm {			/* extension to mime */
91 	const char	*mime;
92 	const char	*ext;
93 };
94 
95 struct mime {
96 	struct etm	*t;
97 	size_t		len;
98 	size_t		cap;
99 };
100 
101 struct conf {
102 	int		 port;
103 	int		 ipv6;
104 	uint32_t	 protos;
105 	struct mime	 mime;
106 	char		*chroot;
107 	char		*user;
108 };
109 
110 extern struct conf conf;
111 extern int exfd;
112 
113 extern volatile sig_atomic_t hupped;
114 
115 struct iri {
116 	char		*schema;
117 	char		*host;
118 	char		*port;
119 	uint16_t	 port_no;
120 	char		*path;
121 	char		*query;
122 	char		*fragment;
123 };
124 
125 struct parser {
126 	char		*iri;
127 	struct iri	*parsed;
128 	const char	*err;
129 };
130 
131 struct client;
132 
133 typedef void (*statefn)(struct pollfd*, struct client*);
134 
135 /*
136  * DFA: handle_handshake is the initial state, close_conn the final.
137  * Sometimes we have an enter_* function to handle the state switch.
138  *
139  * handle_handshake -> handle_open_conn
140  * handle_handshake -> close_conn		// on err
141  *
142  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
143  * handle_open_conn -> handle_dirlist		// ...same
144  * handle_open_conn -> send_file		// ...same
145  * handle_open_conn -> start_reply		// on error
146  *
147  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
148  * handle_cgi_reply -> start_reply	// on error
149  *
150  * handle_cgi -> close_conn
151  *
152  * handle_dirlist -> send_directory_listing
153  * handle_dirlist -> close_conn			// on error
154  *
155  * send_directory_listing -> close_conn
156  *
157  * send_file -> close_conn
158  */
159 struct client {
160 	struct tls	*ctx;
161 	char		 req[GEMINI_URL_LEN];
162 	struct iri	 iri;
163 	char		 domain[DOMAIN_NAME_LEN];
164 	statefn		 state, next;
165 	int		 code;
166 	const char	*meta;
167 	int		 fd, waiting_on_child;
168 	char		 sbuf[1024];	  /* static buffer */
169 	void		*buf, *i;	  /* mmap buffer */
170 	ssize_t		 len, off;	  /* mmap/static buffer  */
171 	DIR		*dir;
172 	struct sockaddr_storage	 addr;
173 	struct vhost	*host;	/* host she's talking to */
174 };
175 
176 enum {
177 	FILE_EXISTS,
178 	FILE_EXECUTABLE,
179 	FILE_DIRECTORY,
180 	FILE_MISSING,
181 };
182 
183 /* gmid.c */
184 __attribute__((format (printf, 1, 2)))
185 __attribute__((__noreturn__))
186 void fatal(const char*, ...);
187 
188 __attribute__((format (printf, 3, 4)))
189 void logs(int, struct client*, const char*, ...);
190 void log_request(struct client*, char*, size_t);
191 
192 void		 sig_handler(int);
193 void		 gen_certificate(const char*, const char*, const char*);
194 void		 mkdirs(const char*);
195 char		*data_dir(void);
196 void		 load_local_cert(const char*, const char*);
197 void		 load_vhosts(void);
198 int		 make_socket(int, int);
199 void		 setup_tls(void);
200 void		 init_config(void);
201 void		 free_config(void);
202 void		 drop_priv(void);
203 void		 usage(const char*);
204 
205 /* provided by lex/yacc */
206 extern FILE *yyin;
207 extern int yylineno;
208 extern int yyparse(void);
209 extern int yylex(void);
210 
211 void		 yyerror(const char*);
212 int		 parse_portno(const char*);
213 void		 parse_conf(const char*);
214 
215 /* mime.c */
216 void		 init_mime(struct mime*);
217 void		 add_mime(struct mime*, const char*, const char*);
218 void		 load_default_mime(struct mime*);
219 const char	*mime(struct vhost*, const char*);
220 
221 /* server.c */
222 const char	*vhost_lang(struct vhost*, const char*);
223 const char	*vhost_default_mime(struct vhost*, const char*);
224 const char	*vhost_index(struct vhost*, const char*);
225 int		 vhost_auto_index(struct vhost*, const char*);
226 void		 mark_nonblock(int);
227 void		 loop(struct tls*, int, int);
228 
229 /* ex.c */
230 int		 send_string(int, const char*);
231 int		 recv_string(int, char**);
232 int		 send_iri(int, struct iri*);
233 int		 recv_iri(int, struct iri*);
234 void		 free_recvd_iri(struct iri*);
235 int		 send_vhost(int, struct vhost*);
236 int		 recv_vhost(int, struct vhost**);
237 int		 send_fd(int, int);
238 int		 recv_fd(int);
239 int		 executor_main(void);
240 
241 /* sandbox.c */
242 void		 sandbox(void);
243 
244 /* utf8.c */
245 int		 valid_multibyte_utf8(struct parser*);
246 char		*utf8_nth(char*, size_t);
247 
248 /* iri.c */
249 int		 parse_iri(char*, struct iri*, const char**);
250 int		 trim_req_iri(char*, const char **);
251 int		 serialize_iri(struct iri*, char*, size_t);
252 
253 /* puny.c */
254 int		 puny_decode(const char*, char*, size_t, const char**);
255 
256 /* utils.c */
257 void		 block_signals(void);
258 void		 unblock_signals(void);
259 int		 starts_with(const char*, const char*);
260 int		 ends_with(const char*, const char*);
261 ssize_t		 filesize(int);
262 char		*absolutify_path(const char*);
263 char		*xstrdup(const char*);
264 
265 #endif