1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1980, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include "rcv.h"
33#include "extern.h"
34
35/*
36 * Mail -- a mail program
37 *
38 * Routines for processing and detecting headlines.
39 */
40
41/*
42 * See if the passed line buffer is a mail header.
43 * Return true if yes.  Note the extreme pains to
44 * accommodate all funny formats.
45 */
46int
47ishead(char linebuf[])
48{
49	struct headline hl;
50	char parbuf[BUFSIZ];
51
52	if (strncmp(linebuf, "From ", 5) != 0)
53		return (0);
54	parse(linebuf, &hl, parbuf);
55	if (hl.l_date == NULL) {
56		fail(linebuf, "No date field");
57		return (0);
58	}
59	if (!isdate(hl.l_date)) {
60		fail(linebuf, "Date field not legal date");
61		return (0);
62	}
63	/*
64	 * I guess we got it!
65	 */
66	return (1);
67}
68
69void
70fail(const char *linebuf __unused, const char *reason __unused)
71{
72
73	/*
74	if (value("debug") == NULL)
75		return;
76	fprintf(stderr, "\"%s\"\nnot a header because %s\n", linebuf, reason);
77	*/
78}
79
80/*
81 * Split a headline into its useful components.
82 * Copy the line into dynamic string space, then set
83 * pointers into the copied line in the passed headline
84 * structure.  Actually, it scans.
85 */
86void
87parse(char line[], struct headline *hl, char pbuf[])
88{
89	char *cp, *sp;
90	char word[LINESIZE];
91
92	hl->l_from = NULL;
93	hl->l_tty = NULL;
94	hl->l_date = NULL;
95	cp = line;
96	sp = pbuf;
97	/*
98	 * Skip over "From" first.
99	 */
100	cp = nextword(cp, word);
101	/*
102	 * Check for missing return-path.
103	 */
104	if (isdate(cp)) {
105		hl->l_date = copyin(cp, &sp);
106		return;
107	}
108	cp = nextword(cp, word);
109	if (strlen(word) > 0)
110		hl->l_from = copyin(word, &sp);
111	if (cp != NULL && strncmp(cp, "tty", 3) == 0) {
112		cp = nextword(cp, word);
113		hl->l_tty = copyin(word, &sp);
114	}
115	if (cp != NULL)
116		hl->l_date = copyin(cp, &sp);
117}
118
119/*
120 * Copy the string on the left into the string on the right
121 * and bump the right (reference) string pointer by the length.
122 * Thus, dynamically allocate space in the right string, copying
123 * the left string into it.
124 */
125char *
126copyin(char *src, char **space)
127{
128	char *cp, *top;
129
130	top = cp = *space;
131	while ((*cp++ = *src++) != '\0')
132		;
133	*space = cp;
134	return (top);
135}
136
137/*
138 * Test to see if the passed string is a ctime(3) generated
139 * date string as documented in the manual.  The template
140 * below is used as the criterion of correctness.
141 * Also, we check for a possible trailing time zone using
142 * the tmztype template.
143 *
144 * If the mail file is created by Sys V (Solaris), there are
145 * no seconds in the time. If the mail is created by another
146 * program such as imapd, it might have timezone as
147 * <-|+>nnnn (-0800 for instance) at the end.
148 */
149
150/*
151 * 'A'	An upper case char
152 * 'a'	A lower case char
153 * ' '	A space
154 * '0'	A digit
155 * 'O'	A digit or space
156 * 'p'	A punctuation char
157 * 'P'	A punctuation char or space
158 * ':'	A colon
159 * 'N'	A new line
160 */
161
162static char *date_formats[] = {
163	"Aaa Aaa O0 00:00:00 0000",	   /* Mon Jan 01 23:59:59 2001 */
164	"Aaa Aaa O0 00:00:00 AAA 0000",	   /* Mon Jan 01 23:59:59 PST 2001 */
165	"Aaa Aaa O0 00:00:00 0000 p0000",  /* Mon Jan 01 23:59:59 2001 -0800 */
166	"Aaa Aaa O0 00:00 0000",	   /* Mon Jan 01 23:59 2001 */
167	"Aaa Aaa O0 00:00 AAA 0000",	   /* Mon Jan 01 23:59 PST 2001 */
168	"Aaa Aaa O0 00:00 0000 p0000",	   /* Mon Jan 01 23:59 2001 -0800 */
169	NULL
170};
171
172int
173isdate(char date[])
174{
175	int i;
176
177	for(i = 0; date_formats[i] != NULL; i++) {
178		if (cmatch(date, date_formats[i]))
179			return (1);
180	}
181	return (0);
182}
183
184/*
185 * Match the given string (cp) against the given template (tp).
186 * Return 1 if they match, 0 if they don't
187 */
188int
189cmatch(char *cp, char *tp)
190{
191
192	while (*cp != '\0' && *tp != '\0')
193		switch (*tp++) {
194		case 'a':
195			if (!islower((unsigned char)*cp++))
196				return (0);
197			break;
198		case 'A':
199			if (!isupper((unsigned char)*cp++))
200				return (0);
201			break;
202		case ' ':
203			if (*cp++ != ' ')
204				return (0);
205			break;
206		case '0':
207			if (!isdigit((unsigned char)*cp++))
208				return (0);
209			break;
210		case 'O':
211			if (*cp != ' ' && !isdigit((unsigned char)*cp))
212				return (0);
213			cp++;
214			break;
215		case 'p':
216			if (!ispunct((unsigned char)*cp++))
217				return (0);
218			break;
219		case 'P':
220			if (*cp != ' ' && !ispunct((unsigned char)*cp))
221				return (0);
222			cp++;
223			break;
224		case ':':
225			if (*cp++ != ':')
226				return (0);
227			break;
228		case 'N':
229			if (*cp++ != '\n')
230				return (0);
231			break;
232		}
233	if (*cp != '\0' || *tp != '\0')
234		return (0);
235	return (1);
236}
237
238/*
239 * Collect a liberal (space, tab delimited) word into the word buffer
240 * passed.  Also, return a pointer to the next word following that,
241 * or NULL if none follow.
242 */
243char *
244nextword(char *wp, char *wbuf)
245{
246	int c;
247
248	if (wp == NULL) {
249		*wbuf = '\0';
250		return (NULL);
251	}
252	while ((c = *wp++) != '\0' && c != ' ' && c != '\t') {
253		*wbuf++ = c;
254		if (c == '"') {
255 			while ((c = *wp++) != '\0' && c != '"')
256 				*wbuf++ = c;
257 			if (c == '"')
258 				*wbuf++ = c;
259			else
260				wp--;
261 		}
262	}
263	*wbuf = '\0';
264	for (; c == ' ' || c == '\t'; c = *wp++)
265		;
266	if (c == '\0')
267		return (NULL);
268	return (wp - 1);
269}
270