head.c revision 77274 
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	8.1 (Berkeley) 6/6/93";
37#endif
38static const char rcsid[] =
39  "$FreeBSD: head/usr.bin/mail/head.c 77274 2001-05-27 20:26:22Z mikeh $";
40#endif /* not lint */
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
155/*
156 * 'A'	An upper case char
157 * 'a'	A lower case char
158 * ' '	A space
159 * '0'	A digit
160 * 'O'	An optional digit or space
161 * ':'	A colon
162 * 'N'	A new line
163 */
164char ctype[] = "Aaa Aaa O0 00:00:00 0000";
165char tmztype[] = "Aaa Aaa O0 00:00:00 AAA 0000";
166
167int
168isdate(date)
169	char date[];
170{
171
172	return (cmatch(date, ctype) || cmatch(date, tmztype));
173}
174
175/*
176 * Match the given string (cp) against the given template (tp).
177 * Return 1 if they match, 0 if they don't
178 */
179int
180cmatch(cp, tp)
181	char *cp, *tp;
182{
183
184	while (*cp != '\0' && *tp != '\0')
185		switch (*tp++) {
186		case 'a':
187			if (!islower(*cp++))
188				return (0);
189			break;
190		case 'A':
191			if (!isupper(*cp++))
192				return (0);
193			break;
194		case ' ':
195			if (*cp++ != ' ')
196				return (0);
197			break;
198		case '0':
199			if (!isdigit(*cp++))
200				return (0);
201			break;
202		case 'O':
203			if (*cp != ' ' && !isdigit(*cp))
204				return (0);
205			cp++;
206			break;
207		case ':':
208			if (*cp++ != ':')
209				return (0);
210			break;
211		case 'N':
212			if (*cp++ != '\n')
213				return (0);
214			break;
215		}
216	if (*cp != '\0' || *tp != '\0')
217		return (0);
218	return (1);
219}
220
221/*
222 * Collect a liberal (space, tab delimited) word into the word buffer
223 * passed.  Also, return a pointer to the next word following that,
224 * or NULL if none follow.
225 */
226char *
227nextword(wp, wbuf)
228	char *wp, *wbuf;
229{
230	int c;
231
232	if (wp == NULL) {
233		*wbuf = '\0';
234		return (NULL);
235	}
236	while ((c = *wp++) != '\0' && c != ' ' && c != '\t') {
237		*wbuf++ = c;
238		if (c == '"') {
239 			while ((c = *wp++) != '\0' && c != '"')
240 				*wbuf++ = c;
241 			if (c == '"')
242 				*wbuf++ = c;
243			else
244				wp--;
245 		}
246	}
247	*wbuf = '\0';
248	for (; c == ' ' || c == '\t'; c = *wp++)
249		;
250	if (c == '\0')
251		return (NULL);
252	return (wp - 1);
253}
254