usr.bin/mail/head.c

   1 /*      $NetBSD: head.c,v 1.24 2013/01/16 15:21:42 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 1.24 2013/01/16 15:21:42 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, const 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                 case '+':
  90                         if (*cp != '+' && *cp != '-')
  91                                 return 0;
  92                         cp++;
  93                         break;
  94                 }
  95         if (*cp || *tp)
  96                 return 0;
  97         return 1;
  98 }
  99
 100 /*
 101  * Test to see if the passed string is a ctime(3) generated
 102  * date string as documented in the manual.  The template
 103  * below is used as the criterion of correctness.
 104  * Also, we check for a possible trailing time zone using
 105  * the tmztype template.
 106  */
 107
 108 /*
 109  * 'A'  An upper case char
 110  * 'a'  A lower case char
 111  * ' '  A space
 112  * '0'  A digit
 113  * 'O'  An optional digit or space
 114  * ':'  A colon
 115  * 'N'  A new line
 116  * '+'  A plus or minus sign
 117  */
 118 static struct cmatch_data {
 119         size_t          tlen;
 120         char const      *tdata;
 121 } const cmatch_data[] = {
 122 #define TSZ(a)  (sizeof(a) - 1), a
 123         { TSZ("Aaa Aaa O0 00:00:00 0000") },            /* BSD ctype */
 124         { TSZ("Aaa Aaa O0 00:00 0000") },               /* SysV ctype */
 125         { TSZ("Aaa Aaa O0 00:00:00 AAA 0000") },        /* BSD tmztype */
 126         { TSZ("Aaa Aaa O0 00:00 AAA 0000") },           /* SysV tmztype */
 127         /*
 128          * RFC 822-alike From_ lines do not conform to RFC 4155, but seem to
 129          * be used in the wild by UW-imap (MBX format plus)
 130          */
 131         { TSZ("Aaa Aaa O0 00:00:00 0000 +0000") },      /* RFC822, UT offset */
 132         /*
 133          * RFC 822 with zone spec:
 134          *    1. military,
 135          *    2. UT,
 136          *    3. north america time zone strings
 137          * note that 1. is strictly speaking not correct as some letters are
 138          * not used
 139          */
 140         { TSZ("Aaa Aaa O0 00:00:00 0000 A") },
 141         { TSZ("Aaa Aaa O0 00:00:00 0000 AA") },
 142         { TSZ("Aaa Aaa O0 00:00:00 0000 AAA") },
 143         { 0, NULL },
 144 };
 145
 146 static int
 147 isdate(const char date[])
 148 {
 149         static size_t cmatch_minlen = 0;
 150         struct cmatch_data const *cmdp;
 151         size_t dl = strlen(date);
 152
 153         if (cmatch_minlen == 0)
 154                 for (cmdp = cmatch_data; cmdp->tdata != NULL; ++cmdp)
 155                         cmatch_minlen = MIN(cmatch_minlen, cmdp->tlen);
 156
 157         if (dl < cmatch_minlen)
 158                 return 0;
 159
 160         for (cmdp = cmatch_data; cmdp->tdata != NULL; ++cmdp)
 161                 if (dl == cmdp->tlen && cmatch(date, cmdp->tdata))
 162                         return 1;
 163
 164         return 0;
 165 }
 166
 167 static void
 168 fail(const char linebuf[], const char reason[])
 169 {
 170 #ifndef FMT_PROG
 171         if (debug)
 172                 (void)fprintf(stderr, "\"%s\"\nnot a header because %s\n",
 173                     linebuf, reason);
 174 #endif
 175 }
 176
 177 /*
 178  * Collect a liberal (space, tab delimited) word into the word buffer
 179  * passed.  Also, return a pointer to the next word following that,
 180  * or NULL if none follow.
 181  */
 182 static const char *
 183 nextword(const char *wp, char *wbuf)
 184 {
 185         if (wp == NULL) {
 186                 *wbuf = 0;
 187                 return NULL;
 188         }
 189         while (*wp && !is_WSP(*wp)) {
 190                 *wbuf++ = *wp;
 191                 if (*wp++ == '"') {
 192                         while (*wp && *wp != '"')
 193                                 *wbuf++ = *wp++;
 194                         if (*wp == '"')
 195                                 *wbuf++ = *wp++;
 196                 }
 197         }
 198         *wbuf = '\0';
 199         wp = skip_WSP(wp);
 200         if (*wp == '\0')
 201                 return NULL;
 202         return wp;
 203 }
 204
 205 /*
 206  * Copy the string on the left into the string on the right
 207  * and bump the right (reference) string pointer by the length.
 208  * Thus, dynamically allocate space in the right string, copying
 209  * the left string into it.
 210  */
 211 static char *
 212 copyin(const char *src, char **space)
 213 {
 214         char *cp;
 215         char *begin;
 216
 217         begin = cp = *space;
 218         while ((*cp++ = *src++) != '\0')
 219                 continue;
 220         *space = cp;
 221         return begin;
 222 }
 223
 224 /*
 225  * Split a headline into its useful components.
 226  * Copy the line into dynamic string space, then set
 227  * pointers into the copied line in the passed headline
 228  * structure.  Actually, it scans.
 229  *
 230  * XXX - line[], pbuf[], and word[] must be LINESIZE in length or
 231  * overflow can occur in nextword() or copyin().
 232  */
 233 PUBLIC void
 234 parse(const char line[], struct headline *hl, char pbuf[])
 235 {
 236         const char *cp;
 237         char *sp;
 238         char word[LINESIZE];
 239
 240         hl->l_from = NULL;
 241         hl->l_tty = NULL;
 242         hl->l_date = NULL;
 243         cp = line;
 244         sp = pbuf;
 245         /*
 246          * Skip over "From" first.
 247          */
 248         cp = nextword(cp, word);
 249         cp = nextword(cp, word);
 250         if (*word)
 251                 hl->l_from = copyin(word, &sp);
 252         if (cp != NULL && cp[0] == 't' && cp[1] == 't' && cp[2] == 'y') {
 253                 cp = nextword(cp, word);
 254                 hl->l_tty = copyin(word, &sp);
 255         }
 256         if (cp != NULL)
 257                 hl->l_date = copyin(cp, &sp);
 258 }
 259
 260 /*
 261  * See if the passed line buffer is a mail header.
 262  * Return true if yes.  Note the extreme pains to
 263  * accommodate all funny formats.
 264  */
 265 PUBLIC int
 266 ishead(const char linebuf[])
 267 {
 268         const char *cp;
 269         struct headline hl;
 270         char parbuf[LINESIZE];
 271
 272         cp = linebuf;
 273         if (*cp++ != 'F' || *cp++ != 'r' || *cp++ != 'o' || *cp++ != 'm' ||
 274             *cp++ != ' ')
 275                 return 0;
 276         parse(linebuf, &hl, parbuf);
 277         if (hl.l_from == NULL || hl.l_date == NULL) {
 278                 fail(linebuf, "No from or date field");
 279                 return 0;
 280         }
 281         if (!isdate(hl.l_date)) {
 282                 fail(linebuf, "Date field not legal date");
 283                 return 0;
 284         }
 285         /*
 286          * I guess we got it!
 287          */
 288         return 1;
 289 }