1 /*
2  * Copyright (c) 2021 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 #include "compat.h"
18 
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 
23 #include "parser.h"
24 #include "utils.h"
25 
26 struct gm_selector {
27 	char		 type;
28 	const char	*ds;
29 	const char	*selector;
30 	const char	*addr;
31 	const char	*port;
32 };
33 
34 static void	gm_parse_selector(char *, struct gm_selector *);
35 
36 static int	gm_parse(struct parser *, const char *, size_t);
37 static int	gm_foreach_line(struct parser *, const char *, size_t);
38 static int	gm_free(struct parser *);
39 static int	gm_serialize(struct parser *, FILE *);
40 
41 void
42 gophermap_initparser(struct parser *p)
43 {
44 	memset(p, 0, sizeof(*p));
45 
46 	p->name = "gophermap";
47 	p->parse = &gm_parse;
48 	p->free = &gm_free;
49 	p->serialize = &gm_serialize;
50 
51 	TAILQ_INIT(&p->head);
52 }
53 
54 static void
55 gm_parse_selector(char *line, struct gm_selector *s)
56 {
57 	s->type = *line++;
58 	s->ds = line;
59 	s->selector = "";
60 	s->addr = "";
61 	s->port = "";
62 
63 	if ((line = strchr(line, '\t')) == NULL)
64 		return;
65 	*line++ = '\0';
66 	s->selector = line;
67 
68 	if ((line = strchr(line, '\t')) == NULL)
69 		return;
70 	*line++ = '\0';
71 	s->addr = line;
72 
73 	if ((line = strchr(line, '\t')) == NULL)
74 		return;
75 	*line++ = '\0';
76 	s->port = line;
77 }
78 
79 static int
80 gm_parse(struct parser *p, const char *buf, size_t size)
81 {
82 	return parser_foreach_line(p, buf, size, gm_foreach_line);
83 }
84 
85 static inline int
86 emit_line(struct parser *p, enum line_type type, struct gm_selector *s)
87 {
88 	struct line *l;
89 	char buf[LINE_MAX], b[2] = {0};
90 
91 	if ((l = calloc(1, sizeof(*l))) == NULL)
92 		goto err;
93 
94 	if ((l->line = strdup(s->ds)) == NULL)
95 		goto err;
96 
97 	switch (l->type = type) {
98 	case LINE_LINK:
99 		if (s->type == 'h' && !strncmp(s->selector, "URL:", 4)) {
100 			strlcpy(buf, s->selector+4, sizeof(buf));
101 		} else {
102 			strlcpy(buf, "gopher://", sizeof(buf));
103 			strlcat(buf, s->addr, sizeof(buf));
104 			strlcat(buf, ":", sizeof(buf));
105 			strlcat(buf, s->port, sizeof(buf));
106 			strlcat(buf, "/", sizeof(buf));
107 			b[0] = s->type;
108 			strlcat(buf, b, sizeof(buf));
109 			if (*s->selector != '/')
110 				strlcat(buf, "/", sizeof(buf));
111 			strlcat(buf, s->selector, sizeof(buf));
112 		}
113 
114 		if ((l->alt = strdup(buf)) == NULL)
115 			goto err;
116 		break;
117 
118 	default:
119 		break;
120 	}
121 
122 	TAILQ_INSERT_TAIL(&p->head, l, lines);
123 
124 	return 1;
125 
126 err:
127 	if (l != NULL) {
128 		free(l->line);
129 		free(l->alt);
130 		free(l);
131 	}
132 	return 0;
133 }
134 
135 static int
136 gm_foreach_line(struct parser *p, const char *line, size_t linelen)
137 {
138 	char buf[LINE_MAX] = {0};
139 	struct gm_selector s = {0};
140 
141 	memcpy(buf, line, MIN(sizeof(buf)-1, linelen));
142 	gm_parse_selector(buf, &s);
143 
144 	switch (s.type) {
145 	case '0':	/* text file */
146 	case '1':	/* gopher submenu */
147 	case '2':	/* CCSO nameserver */
148 	case '4':	/* binhex-encoded file */
149 	case '5':	/* DOS file */
150 	case '6':	/* uuencoded file */
151 	case '7':	/* full-text search */
152 	case '8':	/* telnet */
153 	case '9':	/* binary file */
154 	case '+':	/* mirror or alternate server */
155 	case 'g':	/* gif */
156 	case 'I':	/* image */
157 	case 'T':	/* telnet 3270 */
158 	case ':':	/* gopher+: bitmap image */
159 	case ';':	/* gopher+: movie file */
160 	case 'd':	/* non-canonical: doc */
161 	case 'h':	/* non-canonical: html file */
162 	case 's':	/* non-canonical: sound file */
163 		if (!emit_line(p, LINE_LINK, &s))
164 			return 0;
165 		break;
166 
167 	case 'i':	/* non-canonical: message */
168 		if (!emit_line(p, LINE_TEXT, &s))
169 			return 0;
170 		break;
171 
172 	case '3':	/* error code */
173 		if (!emit_line(p, LINE_QUOTE, &s))
174 			return 0;
175 		break;
176 	}
177 
178 	return 1;
179 }
180 
181 static int
182 gm_free(struct parser *p)
183 {
184 	/* flush the buffer */
185 	if (p->len != 0)
186 		gm_foreach_line(p, p->buf, p->len);
187 
188 	free(p->buf);
189 
190 	return 1;
191 }
192 
193 static inline const char *
194 gopher_skip_selector(const char *path, int *ret_type)
195 {
196 	*ret_type = 0;
197 
198 	if (!strcmp(path, "/") || *path == '\0') {
199 		*ret_type = '1';
200 		return path;
201 	}
202 
203 	if (*path != '/')
204 		return path;
205 	path++;
206 
207 	switch (*ret_type = *path) {
208 	case '0':
209 	case '1':
210 	case '7':
211 		break;
212 
213 	default:
214 		*ret_type = 0;
215 		path -= 1;
216 		return path;
217 	}
218 
219 	return ++path;
220 }
221 
222 static int
223 serialize_link(struct line *line, const char *text, FILE *fp)
224 {
225 	size_t		 portlen = 0;
226 	int		 type;
227 	const char	*uri, *endhost, *port, *path, *colon;
228 
229 	if ((uri = line->alt) == NULL)
230 		return -1;
231 
232 	if (strncmp(uri, "gopher://", 9) != 0)
233 		return fprintf(fp, "h%s\tURL:%s\terror.host\t1\n",
234 		    text, line->alt);
235 
236 	uri += 9; /* skip gopher:// */
237 
238 	path = strchr(uri, '/');
239 	colon = strchr(uri, ':');
240 
241 	if (path != NULL && colon > path)
242 		colon = NULL;
243 
244 	if ((endhost = colon) == NULL &&
245 	    (endhost = path) == NULL)
246 		endhost = strchr(uri, '\0');
247 
248 	if (colon != NULL) {
249 		for (port = colon+1; *port && *port != '/'; ++port)
250 			++portlen;
251 		port = colon+1;
252 	} else {
253 		port = "70";
254 		portlen = 2;
255 	}
256 
257 	if (path == NULL) {
258 		type = '1';
259 		path = "";
260 	} else
261 		path = gopher_skip_selector(path, &type);
262 
263 	return fprintf(fp, "%c%s\t%s\t%.*s\t%.*s\n", type, text,
264 	    path, (int)(endhost - uri), uri, (int)portlen, port);
265 }
266 
267 static int
268 gm_serialize(struct parser *p, FILE *fp)
269 {
270 	struct line	*line;
271 	const char	*text;
272 	int		 r;
273 
274 	TAILQ_FOREACH(line, &p->head, lines) {
275 		if ((text = line->line) == NULL)
276 			text = "";
277 
278 		switch (line->type) {
279 		case LINE_LINK:
280 			r = serialize_link(line, text, fp);
281 			break;
282 
283 		case LINE_TEXT:
284 			r = fprintf(fp, "i%s\t\terror.host\t1\n", text);
285 			break;
286 
287 		case LINE_QUOTE:
288 			r = fprintf(fp, "3%s\t\terror.host\t1\n", text);
289 			break;
290 
291 		default:
292 			/* unreachable */
293 			abort();
294 		}
295 
296 		if (r == -1)
297 			return 0;
298 	}
299 
300 	return 1;
301 }