usr.bin/mail/head.c

   1 /*      $NetBSD: head.c,v 1.20 2006/11/28 18:45:32 christos Exp $       */
   2
   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 <sys/cdefs.h>
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)head.c      8.2 (Berkeley) 4/20/95";
  36 #else
  37 __RCSID("$NetBSD: head.c,v 1.20 2006/11/28 18:45:32 christos Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include "rcv.h"
  42 #include "extern.h"
  43
  44 /*
  45  * Mail -- a mail program
  46  *
  47  * Routines for processing and detecting headlines.
  48  */
  49
  50 /*
  51  * Match the given string (cp) against the given template (tp).
  52  * Return 1 if they match, 0 if they don't
  53  */
  54 static int
  55 cmatch(const char *cp, char *tp)
  56 {
  57
  58         while (*cp && *tp)
  59                 switch (*tp++) {
  60                 case 'a':
  61                         if (!islower((unsigned char)*cp++))
  62                                 return 0;
  63                         break;
  64                 case 'A':
  65                         if (!isupper((unsigned char)*cp++))
  66                                 return 0;
  67                         break;
  68                 case ' ':
  69                         if (*cp++ != ' ')
  70                                 return 0;
  71                         break;
  72                 case '0':
  73                         if (!isdigit((unsigned char)*cp++))
  74                                 return 0;
  75                         break;
  76                 case 'O':
  77                         if (*cp != ' ' && !isdigit((unsigned char)*cp))
  78                                 return 0;
  79                         cp++;
  80                         break;
  81                 case ':':
  82                         if (*cp++ != ':')
  83                                 return 0;
  84                         break;
  85                 case 'N':
  86                         if (*cp++ != '\n')
  87                                 return 0;
  88                         break;
  89                 }
  90         if (*cp || *tp)
  91                 return 0;
  92         return 1;
  93 }
  94
  95 /*
  96  * Test to see if the passed string is a ctime(3) generated
  97  * date string as documented in the manual.  The template
  98  * below is used as the criterion of correctness.
  99  * Also, we check for a possible trailing time zone using
 100  * the tmztype template.
 101  */
 102
 103 /*
 104  * 'A'  An upper case char
 105  * 'a'  A lower case char
 106  * ' '  A space
 107  * '0'  A digit
 108  * 'O'  An optional digit or space
 109  * ':'  A colon
 110  * 'N'  A new line
 111  */
 112 static char ctype[] = "Aaa Aaa O0 00:00:00 0000";
 113 static char SysV_ctype[] = "Aaa Aaa O0 00:00 0000";
 114 static char tmztype[] = "Aaa Aaa O0 00:00:00 AAA 0000";
 115 static char SysV_tmztype[] = "Aaa Aaa O0 00:00 AAA 0000";
 116
 117 static int
 118 isdate(const char date[])
 119 {
 120
 121         return cmatch(date, ctype) ||
 122                cmatch(date, tmztype) ||
 123                cmatch(date, SysV_tmztype) || cmatch(date, SysV_ctype);
 124 }
 125
 126 static void
 127 fail(const char linebuf[], const char reason[])
 128 {
 129 #ifndef FMT_PROG
 130         if (debug)
 131                 (void)fprintf(stderr, "\"%s\"\nnot a header because %s\n",
 132                     linebuf, reason);
 133 #endif
 134 }
 135
 136 /*
 137  * Collect a liberal (space, tab delimited) word into the word buffer
 138  * passed.  Also, return a pointer to the next word following that,
 139  * or NULL if none follow.
 140  */
 141 static const char *
 142 nextword(const char *wp, char *wbuf)
 143 {
 144         if (wp == NULL) {
 145                 *wbuf = 0;
 146                 return NULL;
 147         }
 148         while (*wp && !is_WSP(*wp)) {
 149                 *wbuf++ = *wp;
 150                 if (*wp++ == '"') {
 151                         while (*wp && *wp != '"')
 152                                 *wbuf++ = *wp++;
 153                         if (*wp == '"')
 154                                 *wbuf++ = *wp++;
 155                 }
 156         }
 157         *wbuf = '\0';
 158         wp = skip_WSP(wp);
 159         if (*wp == '\0')
 160                 return NULL;
 161         return wp;
 162 }
 163
 164 /*
 165  * Copy the string on the left into the string on the right
 166  * and bump the right (reference) string pointer by the length.
 167  * Thus, dynamically allocate space in the right string, copying
 168  * the left string into it.
 169  */
 170 static char *
 171 copyin(const char *src, char **space)
 172 {
 173         char *cp;
 174         char *begin;
 175
 176         begin = cp = *space;
 177         while ((*cp++ = *src++) != '\0')
 178                 continue;
 179         *space = cp;
 180         return begin;
 181 }
 182
 183 /*
 184  * Split a headline into its useful components.
 185  * Copy the line into dynamic string space, then set
 186  * pointers into the copied line in the passed headline
 187  * structure.  Actually, it scans.
 188  *
 189  * XXX - line[], pbuf[], and word[] must be LINESIZE in length or
 190  * overflow can occur in nextword() or copyin().
 191  */
 192 PUBLIC void
 193 parse(const char line[], struct headline *hl, char pbuf[])
 194 {
 195         const char *cp;
 196         char *sp;
 197         char word[LINESIZE];
 198
 199         hl->l_from = NULL;
 200         hl->l_tty = NULL;
 201         hl->l_date = NULL;
 202         cp = line;
 203         sp = pbuf;
 204         /*
 205          * Skip over "From" first.
 206          */
 207         cp = nextword(cp, word);
 208         cp = nextword(cp, word);
 209         if (*word)
 210                 hl->l_from = copyin(word, &sp);
 211         if (cp != NULL && cp[0] == 't' && cp[1] == 't' && cp[2] == 'y') {
 212                 cp = nextword(cp, word);
 213                 hl->l_tty = copyin(word, &sp);
 214         }
 215         if (cp != NULL)
 216                 hl->l_date = copyin(cp, &sp);
 217 }
 218
 219 /*
 220  * See if the passed line buffer is a mail header.
 221  * Return true if yes.  Note the extreme pains to
 222  * accomodate all funny formats.
 223  */
 224 PUBLIC int
 225 ishead(const char linebuf[])
 226 {
 227         const char *cp;
 228         struct headline hl;
 229         char parbuf[LINESIZE];
 230
 231         cp = linebuf;
 232         if (*cp++ != 'F' || *cp++ != 'r' || *cp++ != 'o' || *cp++ != 'm' ||
 233             *cp++ != ' ')
 234                 return 0;
 235         parse(linebuf, &hl, parbuf);
 236         if (hl.l_from == NULL || hl.l_date == NULL) {
 237                 fail(linebuf, "No from or date field");
 238                 return 0;
 239         }
 240         if (!isdate(hl.l_date)) {
 241                 fail(linebuf, "Date field not legal date");
 242                 return 0;
 243         }
 244         /*
 245          * I guess we got it!
 246          */
 247         return 1;
 248 }