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softmagic.c

/*
 * Copyright (c) Ian F. Darwin 1986-1995.
 * Software written by Ian F. Darwin and others;
 * maintained 1995-present by Christos Zoulas and others.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice immediately at the beginning of the file, without modification,
 *    this list of conditions, and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * softmagic - interpret variable magic from MAGIC
 */

#include "file.h"
#include "magic.h"
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <time.h>
#include <regex.h>


#ifndef     lint
FILE_RCSID("@(#)$Id: softmagic.c,v 1.76 2005/10/17 19:04:36 christos Exp $")
#endif      /* lint */

private int match(struct magic_set *, struct magic *, uint32_t,
    const unsigned char *, size_t);
private int mget(struct magic_set *, union VALUETYPE *, const unsigned char *,
    struct magic *, size_t, unsigned int);
private int mcheck(struct magic_set *, union VALUETYPE *, struct magic *);
private int32_t mprint(struct magic_set *, union VALUETYPE *, struct magic *);
private void mdebug(uint32_t, const char *, size_t);
private int mcopy(struct magic_set *, union VALUETYPE *, int, int,
    const unsigned char *, size_t, size_t);
private int mconvert(struct magic_set *, union VALUETYPE *, struct magic *);
private int check_mem(struct magic_set *, unsigned int);

/*
 * softmagic - lookup one file in database 
 * (already read from MAGIC by apprentice.c).
 * Passed the name and FILE * of one file to be typed.
 */
/*ARGSUSED1*/           /* nbytes passed for regularity, maybe need later */
protected int
file_softmagic(struct magic_set *ms, const unsigned char *buf, size_t nbytes)
{
      struct mlist *ml;
      for (ml = ms->mlist->next; ml != ms->mlist; ml = ml->next)
            if (match(ms, ml->magic, ml->nmagic, buf, nbytes))
                  return 1;

      return 0;
}

/*
 * Go through the whole list, stopping if you find a match.  Process all
 * the continuations of that match before returning.
 *
 * We support multi-level continuations:
 *
 *    At any time when processing a successful top-level match, there is a
 *    current continuation level; it represents the level of the last
 *    successfully matched continuation.
 *
 *    Continuations above that level are skipped as, if we see one, it
 *    means that the continuation that controls them - i.e, the
 *    lower-level continuation preceding them - failed to match.
 *
 *    Continuations below that level are processed as, if we see one,
 *    it means we've finished processing or skipping higher-level
 *    continuations under the control of a successful or unsuccessful
 *    lower-level continuation, and are now seeing the next lower-level
 *    continuation and should process it.  The current continuation
 *    level reverts to the level of the one we're seeing.
 *
 *    Continuations at the current level are processed as, if we see
 *    one, there's no lower-level continuation that may have failed.
 *
 *    If a continuation matches, we bump the current continuation level
 *    so that higher-level continuations are processed.
 */
private int
match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
    const unsigned char *s, size_t nbytes)
{
      uint32_t magindex = 0;
      unsigned int cont_level = 0;
      int need_separator = 0;
      union VALUETYPE p;
      int32_t oldoff = 0;
      int returnval = 0; /* if a match is found it is set to 1*/
      int firstline = 1; /* a flag to print X\n  X\n- X */

      if (check_mem(ms, cont_level) == -1)
            return -1;

      for (magindex = 0; magindex < nmagic; magindex++) {
            /* if main entry matches, print it... */
            int flush = !mget(ms, &p, s, &magic[magindex], nbytes,
                cont_level);
            if (flush) {
                  if (magic[magindex].reln == '!') flush = 0;
            } else {    
                  switch (mcheck(ms, &p, &magic[magindex])) {
                  case -1:
                        return -1;
                  case 0:
                        flush++;
                        break;
                  default:
                        break;
                  }
            }
            if (flush) {
                  /* 
                   * main entry didn't match,
                   * flush its continuations
                   */
                  while (magindex < nmagic - 1 &&
                         magic[magindex + 1].cont_level != 0)
                         magindex++;
                  continue;
            }

            if (!firstline) { /* we found another match */
                  /* put a newline and '-' to do some simple formatting*/
                  if (file_printf(ms, "\n- ") == -1)
                        return -1;
            }

            if ((ms->c.off[cont_level] = mprint(ms, &p, &magic[magindex]))
                == -1)
                  return -1;
            /*
             * If we printed something, we'll need to print
             * a blank before we print something else.
             */
            if (magic[magindex].desc[0])
                  need_separator = 1;
            /* and any continuations that match */
            if (check_mem(ms, ++cont_level) == -1)
                  return -1;

            while (magic[magindex+1].cont_level != 0 && 
                   ++magindex < nmagic) {
                  if (cont_level < magic[magindex].cont_level)
                        continue;
                  if (cont_level > magic[magindex].cont_level) {
                        /*
                         * We're at the end of the level
                         * "cont_level" continuations.
                         */
                        cont_level = magic[magindex].cont_level;
                  }
                  oldoff = magic[magindex].offset;
                  if (magic[magindex].flag & OFFADD) {
                        magic[magindex].offset +=
                            ms->c.off[cont_level - 1];
                  }

                  flush = !mget(ms, &p, s, &magic[magindex], nbytes,
                      cont_level);
                  if (flush && magic[magindex].reln != '!')
                        goto done;
                        
                  switch (flush ? 1 : mcheck(ms, &p, &magic[magindex])) {
                  case -1:
                        return -1;
                  case 0:
                        break;
                  default:
                        /*
                         * This continuation matched.
                         * Print its message, with
                         * a blank before it if
                         * the previous item printed
                         * and this item isn't empty.
                         */
                        /* space if previous printed */
                        if (need_separator
                            && (magic[magindex].nospflag == 0)
                           && (magic[magindex].desc[0] != '\0')) {
                              if (file_printf(ms, " ") == -1)
                                    return -1;
                              need_separator = 0;
                        }
                        if ((ms->c.off[cont_level] = mprint(ms, &p,
                            &magic[magindex])) == -1)
                              return -1;
                        if (magic[magindex].desc[0])
                              need_separator = 1;

                        /*
                         * If we see any continuations
                         * at a higher level,
                         * process them.
                         */
                        if (check_mem(ms, ++cont_level) == -1)
                              return -1;
                  }
done:
                  magic[magindex].offset = oldoff;
            }
            firstline = 0;
            returnval = 1;
            if ((ms->flags & MAGIC_CONTINUE) == 0) {
                  return 1; /* don't keep searching */
            }                 
      }
      return returnval;  /* This is hit if -k is set or there is no match */
}

private int
check_mem(struct magic_set *ms, unsigned int level)
{
      size_t len;

      if (level < ms->c.len)
            return 0;

      len = (ms->c.len += 20) * sizeof(*ms->c.off);
      ms->c.off = (ms->c.off == NULL) ? malloc(len) : realloc(ms->c.off, len);
      if (ms->c.off != NULL)
            return 0;
      file_oomem(ms);
      return -1;
}

private int32_t
mprint(struct magic_set *ms, union VALUETYPE *p, struct magic *m)
{
      uint32_t v;
      int32_t t=0 ;


      switch (m->type) {
      case FILE_BYTE:
            v = file_signextend(ms, m, (size_t)p->b);
            if (file_printf(ms, m->desc, (unsigned char) v) == -1)
                  return -1;
            t = m->offset + sizeof(char);
            break;

      case FILE_SHORT:
      case FILE_BESHORT:
      case FILE_LESHORT:
            v = file_signextend(ms, m, (size_t)p->h);
            if (file_printf(ms, m->desc, (unsigned short) v) == -1)
                  return -1;
            t = m->offset + sizeof(short);
            break;

      case FILE_LONG:
      case FILE_BELONG:
      case FILE_LELONG:
            v = file_signextend(ms, m, p->l);
            if (file_printf(ms, m->desc, (uint32_t) v) == -1)
                  return -1;
            t = m->offset + sizeof(int32_t);
            break;

      case FILE_STRING:
      case FILE_PSTRING:
      case FILE_BESTRING16:
      case FILE_LESTRING16:
            if (m->reln == '=' || m->reln == '!') {
                  if (file_printf(ms, m->desc, m->value.s) == -1)
                        return -1;
                  t = m->offset + m->vallen;
            }
            else {
                  if (*m->value.s == '\0') {
                        char *cp = strchr(p->s,'\n');
                        if (cp)
                              *cp = '\0';
                  }
                  if (file_printf(ms, m->desc, p->s) == -1)
                        return -1;
                  t = m->offset + strlen(p->s);
            }
            break;

      case FILE_DATE:
      case FILE_BEDATE:
      case FILE_LEDATE:
            if (file_printf(ms, m->desc, file_fmttime(p->l, 1)) == -1)
                  return -1;
            t = m->offset + sizeof(time_t);
            break;

      case FILE_LDATE:
      case FILE_BELDATE:
      case FILE_LELDATE:
            if (file_printf(ms, m->desc, file_fmttime(p->l, 0)) == -1)
                  return -1;
            t = m->offset + sizeof(time_t);
            break;
      case FILE_REGEX:
            if (file_printf(ms, m->desc, p->s) == -1)
                  return -1;
            t = m->offset + strlen(p->s);
            break;
      case FILE_SEARCH:
            if (file_printf(ms, m->desc, m->value.s) == -1)
                  return -1;
            t = m->offset + m->vallen;
            break;

      default:
            file_error(ms, 0, "invalid m->type (%d) in mprint()", m->type);
            return -1;
      }
      return(t);
}

/*
 * Convert the byte order of the data we are looking at
 * While we're here, let's apply the mask operation
 * (unless you have a better idea)
 */
private int
mconvert(struct magic_set *ms, union VALUETYPE *p, struct magic *m)
{
      switch (m->type) {
      case FILE_BYTE:
            if (m->mask)
                  switch (m->mask_op & 0x7F) {
                  case FILE_OPAND:
                        p->b &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->b |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->b ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->b += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->b -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->b *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->b /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->b %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->b = ~p->b;
            return 1;
      case FILE_SHORT:
            if (m->mask)
                  switch (m->mask_op & 0x7F) {
                  case FILE_OPAND:
                        p->h &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->h |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->h ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->h += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->h -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->h *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->h /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->h %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->h = ~p->h;
            return 1;
      case FILE_LONG:
      case FILE_DATE:
      case FILE_LDATE:
            if (m->mask)
                  switch (m->mask_op & 0x7F) {
                  case FILE_OPAND:
                        p->l &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->l |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->l ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->l += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->l -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->l *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->l /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->l %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->l = ~p->l;
            return 1;
      case FILE_STRING:
      case FILE_BESTRING16:
      case FILE_LESTRING16:
            {
                  size_t len;

                  /* Null terminate and eat *trailing* return */
                  p->s[sizeof(p->s) - 1] = '\0';
                  len = strlen(p->s);
                  if (len-- && p->s[len] == '\n')
                        p->s[len] = '\0';
                  return 1;
            }
      case FILE_PSTRING:
            {
                  char *ptr1 = p->s, *ptr2 = ptr1 + 1;
                  size_t len = *p->s;
                  if (len >= sizeof(p->s))
                        len = sizeof(p->s) - 1;
                  while (len--)
                        *ptr1++ = *ptr2++;
                  *ptr1 = '\0';
                  len = strlen(p->s);
                  if (len-- && p->s[len] == '\n')
                        p->s[len] = '\0';
                  return 1;
            }
      case FILE_BESHORT:
            p->h = (short)((p->hs[0]<<8)|(p->hs[1]));
            if (m->mask)
                  switch (m->mask_op&0x7F) {
                  case FILE_OPAND:
                        p->h &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->h |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->h ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->h += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->h -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->h *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->h /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->h %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->h = ~p->h;
            return 1;
      case FILE_BELONG:
      case FILE_BEDATE:
      case FILE_BELDATE:
            p->l = (int32_t)
                ((p->hl[0]<<24)|(p->hl[1]<<16)|(p->hl[2]<<8)|(p->hl[3]));
            if (m->mask)
                  switch (m->mask_op&0x7F) {
                  case FILE_OPAND:
                        p->l &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->l |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->l ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->l += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->l -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->l *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->l /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->l %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->l = ~p->l;
            return 1;
      case FILE_LESHORT:
            p->h = (short)((p->hs[1]<<8)|(p->hs[0]));
            if (m->mask)
                  switch (m->mask_op&0x7F) {
                  case FILE_OPAND:
                        p->h &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->h |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->h ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->h += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->h -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->h *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->h /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->h %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->h = ~p->h;
            return 1;
      case FILE_LELONG:
      case FILE_LEDATE:
      case FILE_LELDATE:
            p->l = (int32_t)
                ((p->hl[3]<<24)|(p->hl[2]<<16)|(p->hl[1]<<8)|(p->hl[0]));
            if (m->mask)
                  switch (m->mask_op&0x7F) {
                  case FILE_OPAND:
                        p->l &= m->mask;
                        break;
                  case FILE_OPOR:
                        p->l |= m->mask;
                        break;
                  case FILE_OPXOR:
                        p->l ^= m->mask;
                        break;
                  case FILE_OPADD:
                        p->l += m->mask;
                        break;
                  case FILE_OPMINUS:
                        p->l -= m->mask;
                        break;
                  case FILE_OPMULTIPLY:
                        p->l *= m->mask;
                        break;
                  case FILE_OPDIVIDE:
                        p->l /= m->mask;
                        break;
                  case FILE_OPMODULO:
                        p->l %= m->mask;
                        break;
                  }
            if (m->mask_op & FILE_OPINVERSE)
                  p->l = ~p->l;
            return 1;
      case FILE_REGEX:
      case FILE_SEARCH:
            return 1;
      default:
            file_error(ms, 0, "invalid type %d in mconvert()", m->type);
            return 0;
      }
}


private void
mdebug(uint32_t offset, const char *str, size_t len)
{
      (void) fprintf(stderr, "mget @%d: ", offset);
      file_showstr(stderr, str, len);
      (void) fputc('\n', stderr);
      (void) fputc('\n', stderr);
}

private int
mcopy(struct magic_set *ms, union VALUETYPE *p, int type, int indir,
    const unsigned char *s, size_t offset, size_t nbytes)
{
      if (type == FILE_REGEX && indir == 0) {
            /*
             * offset is interpreted as last line to search,
             * (starting at 1), not as bytes-from start-of-file
             */
            char *b, *c, *last = NULL;
            if ((p->search.buf = strdup((const char *)s)) == NULL) {
                  file_oomem(ms);
                  return -1;
            }
            for (b = p->search.buf; offset && 
                ((b = strchr(c = b, '\n')) || (b = strchr(c, '\r')));
                offset--, b++) {
                  last = b;
                  if (b[0] == '\r' && b[1] == '\n') b++;
            }
            if (last != NULL)
                  *last = '\0';
            p->search.buflen = last - p->search.buf;
            return 0;
      }

      if (indir == 0 && (type == FILE_BESTRING16 || type == FILE_LESTRING16))
      {
            const unsigned char *src = s + offset;
            const unsigned char *esrc = s + nbytes;
            char *dst = p->s, *edst = &p->s[sizeof(p->s) - 1];

            if (type == FILE_BESTRING16)
                  src++;

            for (;src < esrc; src++, dst++) {
                  if (dst < edst)
                        *dst = *src++;
                  else
                        break;
                  if (*dst == '\0')
                        *dst = ' ';
            }
            *edst = '\0';
            return 0;
      }

      if (offset >= nbytes) {
            (void)memset(p, '\0', sizeof(*p));
            return 0;
      }
      if (nbytes - offset < sizeof(*p))
            nbytes = nbytes - offset;
      else
            nbytes = sizeof(*p);

      (void)memcpy(p, s + offset, nbytes);

      /*
       * the usefulness of padding with zeroes eludes me, it
       * might even cause problems
       */
      if (nbytes < sizeof(*p))
            (void)memset(((char *)(void *)p) + nbytes, '\0',
                sizeof(*p) - nbytes);
      return 0;
}

private int
mget(struct magic_set *ms, union VALUETYPE *p, const unsigned char *s,
    struct magic *m, size_t nbytes, unsigned int cont_level)
{
      uint32_t offset = m->offset;

      if (mcopy(ms, p, m->type, m->flag & INDIR, s, offset, nbytes) == -1)
            return -1;

      if ((ms->flags & MAGIC_DEBUG) != 0) {
            mdebug(offset, (char *)(void *)p, sizeof(union VALUETYPE));
            file_mdump(m);
      }

      if (m->flag & INDIR) {
            int off = m->in_offset;
            if (m->in_op & FILE_OPINDIRECT) {
                  const union VALUETYPE *q =
                      ((const void *)(s + offset + off));
                  switch (m->in_type) {
                  case FILE_BYTE:
                        off = q->b;
                        break;
                  case FILE_SHORT:
                        off = q->h;
                        break;
                  case FILE_BESHORT:
                        off = (short)((q->hs[0]<<8)|(q->hs[1]));
                        break;
                  case FILE_LESHORT:
                        off = (short)((q->hs[1]<<8)|(q->hs[0]));
                        break;
                  case FILE_LONG:
                        off = q->l;
                        break;
                  case FILE_BELONG:
                        off = (int32_t)((q->hl[0]<<24)|(q->hl[1]<<16)|
                                     (q->hl[2]<<8)|(q->hl[3]));
                        break;
                  case FILE_LELONG:
                        off = (int32_t)((q->hl[3]<<24)|(q->hl[2]<<16)|
                                     (q->hl[1]<<8)|(q->hl[0]));
                        break;
                  }
            }
            switch (m->in_type) {
            case FILE_BYTE:
                  if (nbytes < (offset + 1)) return 0;
                  if (off) {
                        switch (m->in_op & 0x3F) {
                        case FILE_OPAND:
                              offset = p->b & off;
                              break;
                        case FILE_OPOR:
                              offset = p->b | off;
                              break;
                        case FILE_OPXOR:
                              offset = p->b ^ off;
                              break;
                        case FILE_OPADD:
                              offset = p->b + off;
                              break;
                        case FILE_OPMINUS:
                              offset = p->b - off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = p->b * off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = p->b / off;
                              break;
                        case FILE_OPMODULO:
                              offset = p->b % off;
                              break;
                        }
                  } else
                        offset = p->b;
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_BESHORT:
                  if (nbytes < (offset + 2))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) &
                                     off;
                              break;
                        case FILE_OPOR:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) |
                                     off;
                              break;
                        case FILE_OPXOR:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) ^
                                     off;
                              break;
                        case FILE_OPADD:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) +
                                     off;
                              break;
                        case FILE_OPMINUS:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) -
                                     off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) *
                                     off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) /
                                     off;
                              break;
                        case FILE_OPMODULO:
                              offset = (short)((p->hs[0]<<8)|
                                           (p->hs[1])) %
                                     off;
                              break;
                        }
                  } else
                        offset = (short)((p->hs[0]<<8)|
                                     (p->hs[1]));
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_LESHORT:
                  if (nbytes < (offset + 2))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) &
                                     off;
                              break;
                        case FILE_OPOR:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) |
                                     off;
                              break;
                        case FILE_OPXOR:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) ^
                                     off;
                              break;
                        case FILE_OPADD:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) +
                                     off;
                              break;
                        case FILE_OPMINUS:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) -
                                     off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) *
                                     off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) /
                                     off;
                              break;
                        case FILE_OPMODULO:
                              offset = (short)((p->hs[1]<<8)|
                                           (p->hs[0])) %
                                     off;
                              break;
                        }
                  } else
                        offset = (short)((p->hs[1]<<8)|
                                     (p->hs[0]));
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_SHORT:
                  if (nbytes < (offset + 2))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = p->h & off;
                              break;
                        case FILE_OPOR:
                              offset = p->h | off;
                              break;
                        case FILE_OPXOR:
                              offset = p->h ^ off;
                              break;
                        case FILE_OPADD:
                              offset = p->h + off;
                              break;
                        case FILE_OPMINUS:
                              offset = p->h - off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = p->h * off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = p->h / off;
                              break;
                        case FILE_OPMODULO:
                              offset = p->h % off;
                              break;
                        }
                  }
                  else
                        offset = p->h;
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_BELONG:
                  if (nbytes < (offset + 4))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) &
                                     off;
                              break;
                        case FILE_OPOR:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) |
                                     off;
                              break;
                        case FILE_OPXOR:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) ^
                                     off;
                              break;
                        case FILE_OPADD:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) +
                                     off;
                              break;
                        case FILE_OPMINUS:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) -
                                     off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) *
                                     off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) /
                                     off;
                              break;
                        case FILE_OPMODULO:
                              offset = (int32_t)((p->hl[0]<<24)|
                                           (p->hl[1]<<16)|
                                           (p->hl[2]<<8)|
                                           (p->hl[3])) %
                                     off;
                              break;
                        }
                  } else
                        offset = (int32_t)((p->hl[0]<<24)|
                                     (p->hl[1]<<16)|
                                     (p->hl[2]<<8)|
                                     (p->hl[3]));
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_LELONG:
                  if (nbytes < (offset + 4))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) &
                                     off;
                              break;
                        case FILE_OPOR:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) |
                                     off;
                              break;
                        case FILE_OPXOR:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) ^
                                     off;
                              break;
                        case FILE_OPADD:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) +
                                     off;
                              break;
                        case FILE_OPMINUS:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) -
                                     off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) *
                                     off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) /
                                     off;
                              break;
                        case FILE_OPMODULO:
                              offset = (int32_t)((p->hl[3]<<24)|
                                           (p->hl[2]<<16)|
                                           (p->hl[1]<<8)|
                                           (p->hl[0])) %
                                     off;
                              break;
                        }
                  } else
                        offset = (int32_t)((p->hl[3]<<24)|
                                     (p->hl[2]<<16)|
                                     (p->hl[1]<<8)|
                                     (p->hl[0]));
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            case FILE_LONG:
                  if (nbytes < (offset + 4))
                        return 0;
                  if (off) {
                        switch (m->in_op & 0x7F) {
                        case FILE_OPAND:
                              offset = p->l & off;
                              break;
                        case FILE_OPOR:
                              offset = p->l | off;
                              break;
                        case FILE_OPXOR:
                              offset = p->l ^ off;
                              break;
                        case FILE_OPADD:
                              offset = p->l + off;
                              break;
                        case FILE_OPMINUS:
                              offset = p->l - off;
                              break;
                        case FILE_OPMULTIPLY:
                              offset = p->l * off;
                              break;
                        case FILE_OPDIVIDE:
                              offset = p->l / off;
                              break;
                        case FILE_OPMODULO:
                              offset = p->l % off;
                              break;
                  /*    case TOOMANYSWITCHBLOCKS:
                   *          ugh = p->eye % m->strain;
                   *          rub;
                   *    case BEER:
                   *          off = p->tab & m->in_gest;
                   *          sleep;
                   */
                        }
                  } else
                        offset = p->l;
                  if (m->in_op & FILE_OPINVERSE)
                        offset = ~offset;
                  break;
            }

            if (m->flag & INDIROFFADD) offset += ms->c.off[cont_level-1];
            if (mcopy(ms, p, m->type, 0, s, offset, nbytes) == -1)
                  return -1;
            m->offset = offset;

            if ((ms->flags & MAGIC_DEBUG) != 0) {
                  mdebug(offset, (char *)(void *)p,
                      sizeof(union VALUETYPE));
                  file_mdump(m);
            }
      }

      /* Verify we have enough data to match magic type */
      switch (m->type) {
            case FILE_BYTE:
                  if (nbytes < (offset + 1)) /* should alway be true */
                        return 0;
                  break;

            case FILE_SHORT:
            case FILE_BESHORT:
            case FILE_LESHORT:
                  if (nbytes < (offset + 2))
                        return 0;
                  break;

            case FILE_LONG:
            case FILE_BELONG:
            case FILE_LELONG:
            case FILE_DATE:
            case FILE_BEDATE:
            case FILE_LEDATE:
            case FILE_LDATE:
            case FILE_BELDATE:
            case FILE_LELDATE:
                  if (nbytes < (offset + 4))
                        return 0;
                  break;

            case FILE_STRING:
            case FILE_PSTRING:
            case FILE_SEARCH:
                  if (nbytes < (offset + m->vallen))
                        return 0;
                  break;
            default: break;
      }

      if (m->type == FILE_SEARCH) {
            size_t mlen = m->mask + m->vallen;
            size_t flen = nbytes - offset;
            if (flen < mlen)
                  mlen = flen;
            p->search.buflen = mlen;
            p->search.buf = malloc(mlen + 1);
            if (p->search.buf == NULL) {
                  file_error(ms, errno, "Cannot allocate search buffer");
                  return 0;
            }
            (void)memcpy(p->search.buf, s + offset, mlen);
            p->search.buf[mlen] = '\0';
      }
      if (!mconvert(ms, p, m))
            return 0;
      return 1;
}

private int
mcheck(struct magic_set *ms, union VALUETYPE *p, struct magic *m)
{
      uint32_t l = m->value.l;
      uint32_t v;
      int matched;

      if ( (m->value.s[0] == 'x') && (m->value.s[1] == '\0') ) {
            return 1;
      }


      switch (m->type) {
      case FILE_BYTE:
            v = p->b;
            break;

      case FILE_SHORT:
      case FILE_BESHORT:
      case FILE_LESHORT:
            v = p->h;
            break;

      case FILE_LONG:
      case FILE_BELONG:
      case FILE_LELONG:
      case FILE_DATE:
      case FILE_BEDATE:
      case FILE_LEDATE:
      case FILE_LDATE:
      case FILE_BELDATE:
      case FILE_LELDATE:
            v = p->l;
            break;

      case FILE_STRING:
      case FILE_BESTRING16:
      case FILE_LESTRING16:
      case FILE_PSTRING:
      {
            /*
             * What we want here is:
             * v = strncmp(m->value.s, p->s, m->vallen);
             * but ignoring any nulls.  bcmp doesn't give -/+/0
             * and isn't universally available anyway.
             */
            unsigned char *a = (unsigned char*)m->value.s;
            unsigned char *b = (unsigned char*)p->s;
            int len = m->vallen;
            l = 0;
            v = 0;
            if (0L == m->mask) { /* normal string: do it fast */
                  while (--len >= 0)
                        if ((v = *b++ - *a++) != '\0')
                              break; 
            } else { /* combine the others */
                  while (--len >= 0) {
                        if ((m->mask & STRING_IGNORE_LOWERCASE) &&
                            islower(*a)) {
                              if ((v = tolower(*b++) - *a++) != '\0')
                                    break;
                        } else if ((m->mask & STRING_COMPACT_BLANK) && 
                            isspace(*a)) { 
                              a++;
                              if (isspace(*b++)) {
                                    while (isspace(*b))
                                          b++;
                              } else {
                                    v = 1;
                                    break;
                              }
                        } else if (isspace(*a) &&
                            (m->mask & STRING_COMPACT_OPTIONAL_BLANK)) {
                              a++;
                              while (isspace(*b))
                                    b++;
                        } else {
                              if ((v = *b++ - *a++) != '\0')
                                    break;
                        }
                  }
            }
            break;
      }
      case FILE_REGEX:
      {
            int rc;
            regex_t rx;
            char errmsg[512];

            if (p->search.buf == NULL)
                  return 0;

            rc = regcomp(&rx, m->value.s,
                REG_EXTENDED|REG_NOSUB|REG_NEWLINE|
                ((m->mask & STRING_IGNORE_LOWERCASE) ? REG_ICASE : 0));
            if (rc) {
                  free(p->search.buf);
                  p->search.buf = NULL;
                  regerror(rc, &rx, errmsg, sizeof(errmsg));
                  file_error(ms, 0, "regex error %d, (%s)", rc, errmsg);
                  return -1;
            } else {
                  rc = regexec(&rx, p->search.buf, 0, 0, 0);
                  regfree(&rx);
                  free(p->search.buf);
                  p->search.buf = NULL;
                  return !rc;
            }
      }
      case FILE_SEARCH:
      {
            /*
             * search for a string in a certain range
             */
            unsigned char *a = (unsigned char*)m->value.s;
            unsigned char *b = (unsigned char*)p->search.buf;
            size_t len, slen = m->vallen;
            size_t range = 0;
            if (slen > sizeof(m->value.s))
                  slen = sizeof(m->value.s);
            l = 0;
            v = 0;
            if (b == NULL)
                  return 0;
            len = slen;
            while (++range <= m->mask) {
                  while (len-- > 0 && (v = *b++ - *a++) == 0)
                        continue;
                  if (!v) {
                        m->offset += range - 1;
                        break;
                  }
                  if (range + slen >= p->search.buflen)
                        break;
                  len = slen;
                  a = (unsigned char*)m->value.s;
                  b = (unsigned char*)p->search.buf + range;
            }
            free(p->search.buf);
            p->search.buf = NULL;
            break;
      }
      default:
            file_error(ms, 0, "invalid type %d in mcheck()", m->type);
            return -1;
      }

      if (m->type != FILE_STRING && m->type != FILE_PSTRING)
            v = file_signextend(ms, m, v);

      switch (m->reln) {
      case 'x':
            if ((ms->flags & MAGIC_DEBUG) != 0)
                  (void) fprintf(stderr, "%u == *any* = 1\n", v);
            matched = 1;
            break;

      case '!':
            matched = v != l;
            if ((ms->flags & MAGIC_DEBUG) != 0)
                  (void) fprintf(stderr, "%u != %u = %d\n",
                               v, l, matched);
            break;

      case '=':
            matched = v == l;
            if ((ms->flags & MAGIC_DEBUG) != 0)
                  (void) fprintf(stderr, "%u == %u = %d\n",
                               v, l, matched);
            break;

      case '>':
            if (m->flag & UNSIGNED) {
                  matched = v > l;
                  if ((ms->flags & MAGIC_DEBUG) != 0)
                        (void) fprintf(stderr, "%u > %u = %d\n",
                                     v, l, matched);
            }
            else {
                  matched = (int32_t) v > (int32_t) l;
                  if ((ms->flags & MAGIC_DEBUG) != 0)
                        (void) fprintf(stderr, "%d > %d = %d\n",
                                     v, l, matched);
            }
            break;

      case '<':
            if (m->flag & UNSIGNED) {
                  matched = v < l;
                  if ((ms->flags & MAGIC_DEBUG) != 0)
                        (void) fprintf(stderr, "%u < %u = %d\n",
                                     v, l, matched);
            }
            else {
                  matched = (int32_t) v < (int32_t) l;
                  if ((ms->flags & MAGIC_DEBUG) != 0)
                        (void) fprintf(stderr, "%d < %d = %d\n",
                                     v, l, matched);
            }
            break;

      case '&':
            matched = (v & l) == l;
            if ((ms->flags & MAGIC_DEBUG) != 0)
                  (void) fprintf(stderr, "((%x & %x) == %x) = %d\n",
                               v, l, l, matched);
            break;

      case '^':
            matched = (v & l) != l;
            if ((ms->flags & MAGIC_DEBUG) != 0)
                  (void) fprintf(stderr, "((%x & %x) != %x) = %d\n",
                               v, l, l, matched);
            break;

      default:
            matched = 0;
            file_error(ms, 0, "cannot happen: invalid relation `%c'",
                m->reln);
            return -1;
      }

      return matched;
}

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