head.c revision 99112 
1/*
2 * Copyright (c) 1980, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35#if 0
36static char sccsid[] = "@(#)head.c	8.2 (Berkeley) 4/20/95";
37#endif
38#endif /* not lint */
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD: head/usr.bin/mail/head.c 99112 2002-06-30 05:25:07Z obrien $");
41
42#include "rcv.h"
43#include "extern.h"
44
45/*
46 * Mail -- a mail program
47 *
48 * Routines for processing and detecting headlines.
49 */
50
51/*
52 * See if the passed line buffer is a mail header.
53 * Return true if yes.  Note the extreme pains to
54 * accomodate all funny formats.
55 */
56int
57ishead(linebuf)
58	char linebuf[];
59{
60	struct headline hl;
61	char parbuf[BUFSIZ];
62
63	if (strncmp(linebuf, "From ", 5))
64		return (0);
65	parse(linebuf, &hl, parbuf);
66	if (hl.l_from == NULL || hl.l_date == NULL) {
67		fail(linebuf, "No from or date field");
68		return (0);
69	}
70	if (!isdate(hl.l_date)) {
71		fail(linebuf, "Date field not legal date");
72		return (0);
73	}
74	/*
75	 * I guess we got it!
76	 */
77	return (1);
78}
79
80/*ARGSUSED*/
81void
82fail(linebuf, reason)
83	const char *linebuf, *reason;
84{
85
86	/*
87	if (value("debug") == NULL)
88		return;
89	fprintf(stderr, "\"%s\"\nnot a header because %s\n", linebuf, reason);
90	*/
91}
92
93/*
94 * Split a headline into its useful components.
95 * Copy the line into dynamic string space, then set
96 * pointers into the copied line in the passed headline
97 * structure.  Actually, it scans.
98 */
99void
100parse(line, hl, pbuf)
101	char line[], pbuf[];
102	struct headline *hl;
103{
104	char *cp, *sp;
105	char word[LINESIZE];
106
107	hl->l_from = NULL;
108	hl->l_tty = NULL;
109	hl->l_date = NULL;
110	cp = line;
111	sp = pbuf;
112	/*
113	 * Skip over "From" first.
114	 */
115	cp = nextword(cp, word);
116	cp = nextword(cp, word);
117	if (*word != '\0')
118		hl->l_from = copyin(word, &sp);
119	if (cp != NULL && cp[0] == 't' && cp[1] == 't' && cp[2] == 'y') {
120		cp = nextword(cp, word);
121		hl->l_tty = copyin(word, &sp);
122	}
123	if (cp != NULL)
124		hl->l_date = copyin(cp, &sp);
125}
126
127/*
128 * Copy the string on the left into the string on the right
129 * and bump the right (reference) string pointer by the length.
130 * Thus, dynamically allocate space in the right string, copying
131 * the left string into it.
132 */
133char *
134copyin(src, space)
135	char *src;
136	char **space;
137{
138	char *cp, *top;
139
140	top = cp = *space;
141	while ((*cp++ = *src++) != '\0')
142		;
143	*space = cp;
144	return (top);
145}
146
147/*
148 * Test to see if the passed string is a ctime(3) generated
149 * date string as documented in the manual.  The template
150 * below is used as the criterion of correctness.
151 * Also, we check for a possible trailing time zone using
152 * the tmztype template.
153 *
154 * If the mail file is created by Sys V (Solaris), there are
155 * no seconds in the time. If the mail is created by another
156 * program such as imapd, it might have timezone as
157 * <-|+>nnnn (-0800 for instance) at the end.
158 */
159
160/*
161 * 'A'	An upper case char
162 * 'a'	A lower case char
163 * ' '	A space
164 * '0'	A digit
165 * 'O'	A digit or space
166 * 'p'	A punctuation char
167 * 'P'	A punctuation char or space
168 * ':'	A colon
169 * 'N'	A new line
170 */
171
172static char *date_formats[] = {
173	"Aaa Aaa O0 00:00:00 0000",	   /* Mon Jan 01 23:59:59 2001 */
174	"Aaa Aaa O0 00:00:00 AAA 0000",	   /* Mon Jan 01 23:59:59 PST 2001 */
175	"Aaa Aaa O0 00:00:00 0000 p0000",  /* Mon Jan 01 23:59:59 2001 -0800 */
176	"Aaa Aaa O0 00:00 0000",	   /* Mon Jan 01 23:59 2001 */
177	"Aaa Aaa O0 00:00 AAA 0000",	   /* Mon Jan 01 23:59 PST 2001 */
178	"Aaa Aaa O0 00:00 0000 p0000",	   /* Mon Jan 01 23:59 2001 -0800 */
179	NULL
180};
181
182int
183isdate(date)
184	char date[];
185{
186	int i;
187
188	for(i = 0; date_formats[i] != NULL; i++) {
189		if (cmatch(date, date_formats[i]))
190			return (1);
191	}
192	return (0);
193}
194
195/*
196 * Match the given string (cp) against the given template (tp).
197 * Return 1 if they match, 0 if they don't
198 */
199int
200cmatch(cp, tp)
201	char *cp, *tp;
202{
203
204	while (*cp != '\0' && *tp != '\0')
205		switch (*tp++) {
206		case 'a':
207			if (!islower((unsigned char)*cp++))
208				return (0);
209			break;
210		case 'A':
211			if (!isupper((unsigned char)*cp++))
212				return (0);
213			break;
214		case ' ':
215			if (*cp++ != ' ')
216				return (0);
217			break;
218		case '0':
219			if (!isdigit((unsigned char)*cp++))
220				return (0);
221			break;
222		case 'O':
223			if (*cp != ' ' && !isdigit((unsigned char)*cp))
224				return (0);
225			cp++;
226			break;
227		case 'p':
228			if (!ispunct((unsigned char)*cp++))
229				return (0);
230			break;
231		case 'P':
232			if (*cp != ' ' && !ispunct((unsigned char)*cp))
233				return (0);
234			cp++;
235			break;
236		case ':':
237			if (*cp++ != ':')
238				return (0);
239			break;
240		case 'N':
241			if (*cp++ != '\n')
242				return (0);
243			break;
244		}
245	if (*cp != '\0' || *tp != '\0')
246		return (0);
247	return (1);
248}
249
250/*
251 * Collect a liberal (space, tab delimited) word into the word buffer
252 * passed.  Also, return a pointer to the next word following that,
253 * or NULL if none follow.
254 */
255char *
256nextword(wp, wbuf)
257	char *wp, *wbuf;
258{
259	int c;
260
261	if (wp == NULL) {
262		*wbuf = '\0';
263		return (NULL);
264	}
265	while ((c = *wp++) != '\0' && c != ' ' && c != '\t') {
266		*wbuf++ = c;
267		if (c == '"') {
268 			while ((c = *wp++) != '\0' && c != '"')
269 				*wbuf++ = c;
270 			if (c == '"')
271 				*wbuf++ = c;
272			else
273				wp--;
274 		}
275	}
276	*wbuf = '\0';
277	for (; c == ' ' || c == '\t'; c = *wp++)
278		;
279	if (c == '\0')
280		return (NULL);
281	return (wp - 1);
282}
283