Logo Search packages:      
Sourcecode: file version File versions

apprentice.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.
 */
/*
 * apprentice - make one pass through /etc/magic, learning its secrets.
 */

#include "file.h"
#include "magic.h"
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/param.h>
#ifdef QUICK
#include <sys/mman.h>
#endif

#ifndef     lint
FILE_RCSID("@(#)$Id: apprentice.c,v 1.82 2004/11/24 18:56:04 christos Exp $")
#endif      /* lint */

#define     EATAB {while (isascii((unsigned char) *l) && \
                  isspace((unsigned char) *l))  ++l;}
#define LOWCASE(l) (isupper((unsigned char) (l)) ? \
                  tolower((unsigned char) (l)) : (l))
/*
 * Work around a bug in headers on Digital Unix.
 * At least confirmed for: OSF1 V4.0 878
 */
#if defined(__osf__) && defined(__DECC)
#ifdef MAP_FAILED
#undef MAP_FAILED
#endif
#endif

#ifndef MAP_FAILED
#define MAP_FAILED (void *) -1
#endif

#ifndef MAP_FILE
#define MAP_FILE 0
#endif

#ifndef MAXPATHLEN
#define MAXPATHLEN      1024
#endif

#define IS_STRING(t) ((t) == FILE_STRING || (t) == FILE_PSTRING || \
    (t) == FILE_BESTRING16 || (t) == FILE_LESTRING16)

private int getvalue(struct magic_set *ms, struct magic *, char **);
private int hextoint(int);
private char *getstr(struct magic_set *, char *, char *, int, int *);
private int parse(struct magic_set *, struct magic **, uint32_t *, char *, int);
private void eatsize(char **);
private int apprentice_1(struct magic_set *, const char *, int, struct mlist *);
private int apprentice_file(struct magic_set *, struct magic **, uint32_t *,
    const char *, int);
private void byteswap(struct magic *, uint32_t);
private void bs1(struct magic *);
private uint16_t swap2(uint16_t);
private uint32_t swap4(uint32_t);
private char *mkdbname(const char *, char *, size_t, int);
private int apprentice_map(struct magic_set *, struct magic **, uint32_t *,
    const char *);
private int apprentice_compile(struct magic_set *, struct magic **, uint32_t *,
    const char *);
private int check_format(struct magic_set *, struct magic *);

private size_t maxmagic = 0;
private size_t magicsize = sizeof(struct magic);

#ifdef COMPILE_ONLY

int main(int, char *[]);

int
main(int argc, char *argv[])
{
      int ret;
      struct magic_set *ms;
      char *progname;

      if ((progname = strrchr(argv[0], '/')) != NULL)
            progname++;
      else
            progname = argv[0];

      if (argc != 2) {
            (void)fprintf(stderr, "Usage: %s file\n", progname);
            return 1;
      }

      if ((ms = magic_open(MAGIC_CHECK)) == NULL) {
            (void)fprintf(stderr, "%s: %s\n", progname, strerror(errno));
            return 1;
      }
      ret = magic_compile(ms, argv[1]) == -1 ? 1 : 0;
      if (ret == 1)
            (void)fprintf(stderr, "%s: %s\n", progname, magic_error(ms));
      magic_close(ms);
      return ret;
}
#endif /* COMPILE_ONLY */


/*
 * Handle one file.
 */
private int
apprentice_1(struct magic_set *ms, const char *fn, int action,
    struct mlist *mlist)
{
      struct magic *magic = NULL;
      uint32_t nmagic = 0;
      struct mlist *ml;
      int rv = -1;
      int mapped;

      if (magicsize != FILE_MAGICSIZE) {
            file_error(ms, 0, "magic element size %lu != %lu",
                (unsigned long)sizeof(*magic),
                (unsigned long)FILE_MAGICSIZE);
            return -1;
      }

      if (action == FILE_COMPILE) {
            rv = apprentice_file(ms, &magic, &nmagic, fn, action);
            if (rv != 0)
                  return -1;
            rv = apprentice_compile(ms, &magic, &nmagic, fn);
            free(magic);
            return rv;
      }
#ifndef COMPILE_ONLY
      if ((rv = apprentice_map(ms, &magic, &nmagic, fn)) == -1) {
            if (ms->flags & MAGIC_CHECK)
                  file_magwarn(ms, "using regular magic file `%s'", fn);
            rv = apprentice_file(ms, &magic, &nmagic, fn, action);
            if (rv != 0)
                  return -1;
            mapped = 0;
      }

      if (rv == -1)
            return rv;
      mapped = rv;
           
      if (magic == NULL || nmagic == 0) {
            file_delmagic(magic, mapped, nmagic);
            return -1;
      }

      if ((ml = malloc(sizeof(*ml))) == NULL) {
            file_delmagic(magic, mapped, nmagic);
            file_oomem(ms);
            return -1;
      }

      ml->magic = magic;
      ml->nmagic = nmagic;
      ml->mapped = mapped;

      mlist->prev->next = ml;
      ml->prev = mlist->prev;
      ml->next = mlist;
      mlist->prev = ml;

      return 0;
#endif /* COMPILE_ONLY */
}

protected void
file_delmagic(struct magic *p, int type, size_t entries)
{
      if (p == NULL)
            return;
      switch (type) {
      case 2:
            p--;
            (void)munmap((void *)p, sizeof(*p) * (entries + 1));
            break;
      case 1:
            p--;
            /*FALLTHROUGH*/
      case 0:
            free(p);
            break;
      default:
            abort();
      }
}


/* const char *fn: list of magic files */
protected struct mlist *
file_apprentice(struct magic_set *ms, const char *fn, int action)
{
      char *p, *mfn, *afn = NULL;
      int file_err, errs = -1;
      struct mlist *mlist;

      if (fn == NULL)
            fn = getenv("MAGIC");
      if (fn == NULL)
            fn = MAGIC;

      if ((fn = mfn = strdup(fn)) == NULL) {
            file_oomem(ms);
            return NULL;
      }

      if ((mlist = malloc(sizeof(*mlist))) == NULL) {
            free(mfn);
            file_oomem(ms);
            return NULL;
      }
      mlist->next = mlist->prev = mlist;

      while (fn) {
            p = strchr(fn, PATHSEP);
            if (p)
                  *p++ = '\0';
            if (*fn == '\0')
                  break;
            if (ms->flags & MAGIC_MIME) {
                  if ((afn = malloc(strlen(fn) + 5 + 1)) == NULL) {
                        free(mfn);
                        free(mlist);
                        file_oomem(ms);
                        return NULL;
                  }
                  (void)strcpy(afn, fn);
                  (void)strcat(afn, ".mime");
                  fn = afn;
            }
            file_err = apprentice_1(ms, fn, action, mlist);
            if (file_err > errs)
                  errs = file_err;
            if (afn) {
                  free(afn);
                  afn = NULL;
            }
            fn = p;
      }
      if (errs == -1) {
            free(mfn);
            free(mlist);
            mlist = NULL;
            file_error(ms, 0, "could not find any magic files!");
            return NULL;
      }
      free(mfn);
      return mlist;
}

/*
 * parse from a file
 * const char *fn: name of magic file
 */
private int
apprentice_file(struct magic_set *ms, struct magic **magicp, uint32_t *nmagicp,
    const char *fn, int action)
{
      private const char hdr[] =
            "cont\toffset\ttype\topcode\tmask\tvalue\tdesc";
      FILE *f;
      char line[BUFSIZ+1];
      int errs = 0;

      f = fopen(ms->file = fn, "r");
      if (f == NULL) {
            if (errno != ENOENT)
                  file_error(ms, errno, "cannot read magic file `%s'",
                      fn);
            return -1;
      }

        maxmagic = MAXMAGIS;
      *magicp = (struct magic *) calloc(maxmagic, sizeof(struct magic));
      if (*magicp == NULL) {
            (void)fclose(f);
            file_oomem(ms);
            return -1;
      }

      /* print silly verbose header for USG compat. */
      if (action == FILE_CHECK)
            (void)fprintf(stderr, "%s\n", hdr);

      /* parse it */
      for (ms->line = 1; fgets(line, BUFSIZ, f) != NULL; ms->line++) {
            size_t len;
            if (line[0]=='#') /* comment, do not parse */
                  continue;
            len = strlen(line);
            if (len < 2) /* null line, garbage, etc */
                  continue;
            line[len - 1] = '\0'; /* delete newline */
            if (parse(ms, magicp, nmagicp, line, action) != 0)
                  errs = 1;
      }

      (void)fclose(f);
      if (errs) {
            free(*magicp);
            *magicp = NULL;
            *nmagicp = 0;
      }
      return errs;
}

/*
 * extend the sign bit if the comparison is to be signed
 */
protected uint32_t
file_signextend(struct magic_set *ms, struct magic *m, uint32_t v)
{
      if (!(m->flag & UNSIGNED))
            switch(m->type) {
            /*
             * Do not remove the casts below.  They are
             * vital.  When later compared with the data,
             * the sign extension must have happened.
             */
            case FILE_BYTE:
                  v = (char) v;
                  break;
            case FILE_SHORT:
            case FILE_BESHORT:
            case FILE_LESHORT:
                  v = (short) v;
                  break;
            case FILE_DATE:
            case FILE_BEDATE:
            case FILE_LEDATE:
            case FILE_LDATE:
            case FILE_BELDATE:
            case FILE_LELDATE:
            case FILE_LONG:
            case FILE_BELONG:
            case FILE_LELONG:
                  v = (int32_t) v;
                  break;
            case FILE_STRING:
            case FILE_PSTRING:
            case FILE_BESTRING16:
            case FILE_LESTRING16:
                  break;
            case FILE_REGEX:
                  break;
            default:
                  if (ms->flags & MAGIC_CHECK)
                      file_magwarn(ms, "cannot happen: m->type=%d\n",
                            m->type);
                  return ~0U;
            }
      return v;
}

/*
 * parse one line from magic file, put into magic[index++] if valid
 */
private int
parse(struct magic_set *ms, struct magic **magicp, uint32_t *nmagicp, char *l,
    int action)
{
      int i = 0;
      struct magic *m;
      char *t;
      private const char *fops = FILE_OPS;
      uint32_t val;

#define ALLOC_INCR      200
      if (*nmagicp + 1 >= maxmagic){
            maxmagic += ALLOC_INCR;
            if ((m = (struct magic *) realloc(*magicp,
                sizeof(struct magic) * maxmagic)) == NULL) {
                  file_oomem(ms);
                  if (*magicp)
                        free(*magicp);
                  return -1;
            }
            *magicp = m;
            memset(&(*magicp)[*nmagicp], 0, sizeof(struct magic)
                * ALLOC_INCR);
      }
      m = &(*magicp)[*nmagicp];
      m->flag = 0;
      m->cont_level = 0;

      while (*l == '>') {
            ++l;        /* step over */
            m->cont_level++; 
      }

      if (m->cont_level != 0 && *l == '(') {
            ++l;        /* step over */
            m->flag |= INDIR;
      }
      if (m->cont_level != 0 && *l == '&') {
                ++l;            /* step over */
                m->flag |= OFFADD;
        }

      /* get offset, then skip over it */
      m->offset = (uint32_t)strtoul(l, &t, 0);
        if (l == t)
            if (ms->flags & MAGIC_CHECK)
                  file_magwarn(ms, "offset `%s' invalid", l);
        l = t;

      if (m->flag & INDIR) {
            m->in_type = FILE_LONG;
            m->in_offset = 0;
            /*
             * read [.lbs][+-]nnnnn)
             */
            if (*l == '.') {
                  l++;
                  switch (*l) {
                  case 'l':
                        m->in_type = FILE_LELONG;
                        break;
                  case 'L':
                        m->in_type = FILE_BELONG;
                        break;
                  case 'h':
                  case 's':
                        m->in_type = FILE_LESHORT;
                        break;
                  case 'H':
                  case 'S':
                        m->in_type = FILE_BESHORT;
                        break;
                  case 'c':
                  case 'b':
                  case 'C':
                  case 'B':
                        m->in_type = FILE_BYTE;
                        break;
                  default:
                        if (ms->flags & MAGIC_CHECK)
                              file_magwarn(ms,
                                  "indirect offset type `%c' invalid",
                                  *l);
                        break;
                  }
                  l++;
            }
            if (*l == '~') {
                  m->in_op = FILE_OPINVERSE;
                  l++;
            }
            switch (*l) {
            case '&':
                  m->in_op |= FILE_OPAND;
                  l++;
                  break;
            case '|':
                  m->in_op |= FILE_OPOR;
                  l++;
                  break;
            case '^':
                  m->in_op |= FILE_OPXOR;
                  l++;
                  break;
            case '+':
                  m->in_op |= FILE_OPADD;
                  l++;
                  break;
            case '-':
                  m->in_op |= FILE_OPMINUS;
                  l++;
                  break;
            case '*':
                  m->in_op |= FILE_OPMULTIPLY;
                  l++;
                  break;
            case '/':
                  m->in_op |= FILE_OPDIVIDE;
                  l++;
                  break;
            case '%':
                  m->in_op |= FILE_OPMODULO;
                  l++;
                  break;
            }
            if (isdigit((unsigned char)*l)) 
                  m->in_offset = (uint32_t)strtoul(l, &t, 0);
            else
                  t = l;
            if (*t++ != ')') 
                  if (ms->flags & MAGIC_CHECK)
                        file_magwarn(ms,
                            "missing ')' in indirect offset");
            l = t;
      }


      while (isascii((unsigned char)*l) && isdigit((unsigned char)*l))
            ++l;
      EATAB;

#define NBYTE           4
#define NSHORT          5
#define NLONG           4
#define NSTRING   6
#define NDATE           4
#define NBESHORT  7
#define NBELONG         6
#define NBEDATE         6
#define NLESHORT  7
#define NLELONG         6
#define NLEDATE         6
#define NPSTRING  7
#define NLDATE          5
#define NBELDATE  7
#define NLELDATE  7
#define NREGEX          5
#define NBESTRING16     10
#define NLESTRING16     10

      if (*l == 'u') {
            ++l;
            m->flag |= UNSIGNED;
      }

      /* get type, skip it */
      if (strncmp(l, "char", NBYTE)==0) { /* HP/UX compat */
            m->type = FILE_BYTE;
            l += NBYTE;
      } else if (strncmp(l, "byte", NBYTE)==0) {
            m->type = FILE_BYTE;
            l += NBYTE;
      } else if (strncmp(l, "short", NSHORT)==0) {
            m->type = FILE_SHORT;
            l += NSHORT;
      } else if (strncmp(l, "long", NLONG)==0) {
            m->type = FILE_LONG;
            l += NLONG;
      } else if (strncmp(l, "string", NSTRING)==0) {
            m->type = FILE_STRING;
            l += NSTRING;
      } else if (strncmp(l, "date", NDATE)==0) {
            m->type = FILE_DATE;
            l += NDATE;
      } else if (strncmp(l, "beshort", NBESHORT)==0) {
            m->type = FILE_BESHORT;
            l += NBESHORT;
      } else if (strncmp(l, "belong", NBELONG)==0) {
            m->type = FILE_BELONG;
            l += NBELONG;
      } else if (strncmp(l, "bedate", NBEDATE)==0) {
            m->type = FILE_BEDATE;
            l += NBEDATE;
      } else if (strncmp(l, "leshort", NLESHORT)==0) {
            m->type = FILE_LESHORT;
            l += NLESHORT;
      } else if (strncmp(l, "lelong", NLELONG)==0) {
            m->type = FILE_LELONG;
            l += NLELONG;
      } else if (strncmp(l, "ledate", NLEDATE)==0) {
            m->type = FILE_LEDATE;
            l += NLEDATE;
      } else if (strncmp(l, "pstring", NPSTRING)==0) {
            m->type = FILE_PSTRING;
            l += NPSTRING;
      } else if (strncmp(l, "ldate", NLDATE)==0) {
            m->type = FILE_LDATE;
            l += NLDATE;
      } else if (strncmp(l, "beldate", NBELDATE)==0) {
            m->type = FILE_BELDATE;
            l += NBELDATE;
      } else if (strncmp(l, "leldate", NLELDATE)==0) {
            m->type = FILE_LELDATE;
            l += NLELDATE;
      } else if (strncmp(l, "regex", NREGEX)==0) {
            m->type = FILE_REGEX;
            l += NREGEX;
      } else if (strncmp(l, "bestring16", NBESTRING16)==0) {
            m->type = FILE_BESTRING16;
            l += NBESTRING16;
      } else if (strncmp(l, "lestring16", NLESTRING16)==0) {
            m->type = FILE_LESTRING16;
            l += NLESTRING16;
      } else {
            if (ms->flags & MAGIC_CHECK)
                  file_magwarn(ms, "type `%s' invalid", l);
            return -1;
      }
      /* New-style anding: "0 byte&0x80 =0x80 dynamically linked" */
      /* New and improved: ~ & | ^ + - * / % -- exciting, isn't it? */
      if (*l == '~') {
            if (!IS_STRING(m->type))
                  m->mask_op = FILE_OPINVERSE;
            ++l;
      }
      if ((t = strchr(fops,  *l)) != NULL) {
            uint32_t op = (uint32_t)(t - fops);
            if (op != FILE_OPDIVIDE || !IS_STRING(m->type)) {
                  ++l;
                  m->mask_op |= op;
                  val = (uint32_t)strtoul(l, &l, 0);
                  m->mask = file_signextend(ms, m, val);
                  eatsize(&l);
            } else {
                  m->mask = 0L;
                  while (!isspace((unsigned char)*++l)) {
                        switch (*l) {
                        case CHAR_IGNORE_LOWERCASE:
                              m->mask |= STRING_IGNORE_LOWERCASE;
                              break;
                        case CHAR_COMPACT_BLANK:
                              m->mask |= STRING_COMPACT_BLANK;
                              break;
                        case CHAR_COMPACT_OPTIONAL_BLANK:
                              m->mask |=
                                  STRING_COMPACT_OPTIONAL_BLANK;
                              break;
                        default:
                              if (ms->flags & MAGIC_CHECK)
                                    file_magwarn(ms,
                                    "string extension `%c' invalid",
                                    *l);
                              return -1;
                        }
                  }
            }
      }
      /*
       * We used to set mask to all 1's here, instead let's just not do
       * anything if mask = 0 (unless you have a better idea)
       */
      EATAB;
  
      switch (*l) {
      case '>':
      case '<':
      /* Old-style anding: "0 byte &0x80 dynamically linked" */
      case '&':
      case '^':
      case '=':
            m->reln = *l;
            ++l;
            if (*l == '=') {
               /* HP compat: ignore &= etc. */
               ++l;
            }
            break;
      case '!':
            if (!IS_STRING(m->type)) {
                  m->reln = *l;
                  ++l;
                  break;
            }
            /*FALLTHROUGH*/
      default:
            if (*l == 'x' && isascii((unsigned char)l[1]) && 
                isspace((unsigned char)l[1])) {
                  m->reln = *l;
                  ++l;
                  goto GetDesc;     /* Bill The Cat */
            }
            m->reln = '=';
            break;
      }
      EATAB;
  
      if (getvalue(ms, m, &l))
            return -1;
      /*
       * TODO finish this macro and start using it!
       * #define offsetcheck {if (offset > HOWMANY-1) 
       *    magwarn("offset too big"); }
       */

      /*
       * now get last part - the description
       */
GetDesc:
      EATAB;
      if (l[0] == '\b') {
            ++l;
            m->nospflag = 1;
      } else if ((l[0] == '\\') && (l[1] == 'b')) {
            ++l;
            ++l;
            m->nospflag = 1;
      } else
            m->nospflag = 0;
      while ((m->desc[i++] = *l++) != '\0' && i < MAXDESC)
            /* NULLBODY */;

      if (ms->flags & MAGIC_CHECK) {
            if (!check_format(ms, m))
                  return -1;
      }
#ifndef COMPILE_ONLY
      if (action == FILE_CHECK) {
            file_mdump(m);
      }
#endif
      ++(*nmagicp);           /* make room for next */
      return 0;
}

/*
 * Check that the optional printf format in description matches
 * the type of the magic.
 */
private int
check_format(struct magic_set *ms, struct magic *m)
{
      static const char *formats[] = { FILE_FORMAT_STRING };
      static const char *names[] = { FILE_FORMAT_NAME };
      char *ptr;

      for (ptr = m->desc; *ptr; ptr++)
            if (*ptr == '%')
                  break;
      if (*ptr == '\0') {
            /* No format string; ok */
            return 1;
      }
      if (m->type >= sizeof(formats)/sizeof(formats[0])) {
            file_magwarn(ms, "Internal error inconsistency between m->type"
                " and format strings");
            return 0;
      }
      if (formats[m->type] == NULL) {
            file_magwarn(ms, "No format string for `%s' with description "
                "`%s'", m->desc, names[m->type]);
            return 0;
      }
      for (; *ptr; ptr++) {
            if (*ptr == 'l' || *ptr == 'h') {
                  /* XXX: we should really fix this one day */
                  continue;
            }
            if (islower((unsigned char)*ptr) || *ptr == 'X')
                  break;
      }
      if (*ptr == '\0') {
            /* Missing format string; bad */
            file_magwarn(ms, "Invalid format `%s' for type `%s'",
                  m->desc, names[m->type]);
            return 0;
      }
      if (strchr(formats[m->type], *ptr) == NULL) {
            file_magwarn(ms, "Printf format `%c' is not valid for type `%s'"
                " in description `%s'",
                  *ptr, names[m->type], m->desc);
            return 0;
      }
      return 1;
}

/* 
 * Read a numeric value from a pointer, into the value union of a magic 
 * pointer, according to the magic type.  Update the string pointer to point 
 * just after the number read.  Return 0 for success, non-zero for failure.
 */
private int
getvalue(struct magic_set *ms, struct magic *m, char **p)
{
      int slen;

      switch (m->type) {
      case FILE_BESTRING16:
      case FILE_LESTRING16:
      case FILE_STRING:
      case FILE_PSTRING:
      case FILE_REGEX:
            *p = getstr(ms, *p, m->value.s, sizeof(m->value.s), &slen);
            if (*p == NULL) {
                  if (ms->flags & MAGIC_CHECK)
                        file_magwarn(ms, "cannot get string from `%s'",
                            m->value.s);
                  return -1;
            }
            m->vallen = slen;
            return 0;
      default:
            if (m->reln != 'x') {
                  m->value.l = file_signextend(ms, m,
                      (uint32_t)strtoul(*p, p, 0));
                  eatsize(p);
            }
            return 0;
      }
}

/*
 * Convert a string containing C character escapes.  Stop at an unescaped
 * space or tab.
 * Copy the converted version to "p", returning its length in *slen.
 * Return updated scan pointer as function result.
 */
private char *
getstr(struct magic_set *ms, char *s, char *p, int plen, int *slen)
{
      char  *origs = s, *origp = p;
      char  *pmax = p + plen - 1;
      int   c;
      int   val;

      while ((c = *s++) != '\0') {
            if (isspace((unsigned char) c))
                  break;
            if (p >= pmax) {
                  file_error(ms, 0, "string too long: `%s'", origs);
                  return NULL;
            }
            if(c == '\\') {
                  switch(c = *s++) {

                  case '\0':
                        goto out;

                  default:
                        *p++ = (char) c;
                        break;

                  case 'n':
                        *p++ = '\n';
                        break;

                  case 'r':
                        *p++ = '\r';
                        break;

                  case 'b':
                        *p++ = '\b';
                        break;

                  case 't':
                        *p++ = '\t';
                        break;

                  case 'f':
                        *p++ = '\f';
                        break;

                  case 'v':
                        *p++ = '\v';
                        break;

                  /* \ and up to 3 octal digits */
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                        val = c - '0';
                        c = *s++;  /* try for 2 */
                        if(c >= '0' && c <= '7') {
                              val = (val<<3) | (c - '0');
                              c = *s++;  /* try for 3 */
                              if(c >= '0' && c <= '7')
                                    val = (val<<3) | (c-'0');
                              else
                                    --s;
                        }
                        else
                              --s;
                        *p++ = (char)val;
                        break;

                  /* \x and up to 2 hex digits */
                  case 'x':
                        val = 'x';  /* Default if no digits */
                        c = hextoint(*s++);     /* Get next char */
                        if (c >= 0) {
                              val = c;
                              c = hextoint(*s++);
                              if (c >= 0)
                                    val = (val << 4) + c;
                              else
                                    --s;
                        } else
                              --s;
                        *p++ = (char)val;
                        break;
                  }
            } else
                  *p++ = (char)c;
      }
out:
      *p = '\0';
      *slen = p - origp;
      return s;
}


/* Single hex char to int; -1 if not a hex char. */
private int
hextoint(int c)
{
      if (!isascii((unsigned char) c))
            return -1;
      if (isdigit((unsigned char) c))
            return c - '0';
      if ((c >= 'a')&&(c <= 'f'))
            return c + 10 - 'a';
      if (( c>= 'A')&&(c <= 'F'))
            return c + 10 - 'A';
      return -1;
}


/*
 * Print a string containing C character escapes.
 */
protected void
file_showstr(FILE *fp, const char *s, size_t len)
{
      char  c;

      for (;;) {
            c = *s++;
            if (len == ~0U) {
                  if (c == '\0')
                        break;
            }
            else  {
                  if (len-- == 0)
                        break;
            }
            if(c >= 040 && c <= 0176)     /* TODO isprint && !iscntrl */
                  (void) fputc(c, fp);
            else {
                  (void) fputc('\\', fp);
                  switch (c) {
                  
                  case '\n':
                        (void) fputc('n', fp);
                        break;

                  case '\r':
                        (void) fputc('r', fp);
                        break;

                  case '\b':
                        (void) fputc('b', fp);
                        break;

                  case '\t':
                        (void) fputc('t', fp);
                        break;

                  case '\f':
                        (void) fputc('f', fp);
                        break;

                  case '\v':
                        (void) fputc('v', fp);
                        break;

                  default:
                        (void) fprintf(fp, "%.3o", c & 0377);
                        break;
                  }
            }
      }
}

/*
 * eatsize(): Eat the size spec from a number [eg. 10UL]
 */
private void
eatsize(char **p)
{
      char *l = *p;

      if (LOWCASE(*l) == 'u') 
            l++;

      switch (LOWCASE(*l)) {
      case 'l':    /* long */
      case 's':    /* short */
      case 'h':    /* short */
      case 'b':    /* char/byte */
      case 'c':    /* char/byte */
            l++;
            /*FALLTHROUGH*/
      default:
            break;
      }

      *p = l;
}

/*
 * handle a compiled file.
 */
private int
apprentice_map(struct magic_set *ms, struct magic **magicp, uint32_t *nmagicp,
    const char *fn)
{
      int fd;
      struct stat st;
      uint32_t *ptr;
      uint32_t version;
      int needsbyteswap;
      char buf[MAXPATHLEN];
      char *dbname = mkdbname(fn, buf, sizeof(buf), 0);
      void *mm = NULL;

      if (dbname == NULL)
            return -1;

      if ((fd = open(dbname, O_RDONLY)) == -1)
            return -1;

      if (fstat(fd, &st) == -1) {
            file_error(ms, errno, "cannot stat `%s'", dbname);
            goto error;
      }
      if (st.st_size < 16) {
            file_error(ms, 0, "file `%s' is too small", dbname);
            goto error;
      }

#ifdef QUICK
      if ((mm = mmap(0, (size_t)st.st_size, PROT_READ|PROT_WRITE,
          MAP_PRIVATE|MAP_FILE, fd, (off_t)0)) == MAP_FAILED) {
            file_error(ms, errno, "cannot map `%s'", dbname);
            goto error;
      }
#define RET 2
#else
      if ((mm = malloc((size_t)st.st_size)) == NULL) {
            file_oomem(ms);
            goto error;
      }
      if (read(fd, mm, (size_t)st.st_size) != (size_t)st.st_size) {
            file_badread(ms);
            goto error;
      }
#define RET 1
#endif
      *magicp = mm;
      (void)close(fd);
      fd = -1;
      ptr = (uint32_t *)(void *)*magicp;
      if (*ptr != MAGICNO) {
            if (swap4(*ptr) != MAGICNO) {
                  file_error(ms, 0, "bad magic in `%s'");
                  goto error;
            }
            needsbyteswap = 1;
      } else
            needsbyteswap = 0;
      if (needsbyteswap)
            version = swap4(ptr[1]);
      else
            version = ptr[1];
      if (version != VERSIONNO) {
            file_error(ms, 0, "version mismatch (%d != %d) in `%s'",
                version, VERSIONNO, dbname);
            goto error;
      }
      *nmagicp = (uint32_t)(st.st_size / sizeof(struct magic)) - 1;
      (*magicp)++;
      if (needsbyteswap)
            byteswap(*magicp, *nmagicp);
      return RET;

error:
      if (fd != -1)
            (void)close(fd);
      if (mm) {
#ifdef QUICK
            (void)munmap((void *)mm, (size_t)st.st_size);
#else
            free(mm);
#endif
      } else {
            *magicp = NULL;
            *nmagicp = 0;
      }
      return -1;
}

private const uint32_t ar[] = {
    MAGICNO, VERSIONNO
};
/*
 * handle an mmaped file.
 */
private int
apprentice_compile(struct magic_set *ms, struct magic **magicp,
    uint32_t *nmagicp, const char *fn)
{
      int fd;
      char buf[MAXPATHLEN];
      char *dbname = mkdbname(fn, buf, sizeof(buf), 1);

      if (dbname == NULL) 
            return -1;

      if ((fd = open(dbname, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1) {
            file_error(ms, errno, "cannot open `%s'", dbname);
            return -1;
      }

      if (write(fd, ar, sizeof(ar)) != (ssize_t)sizeof(ar)) {
            file_error(ms, errno, "error writing `%s'", dbname);
            return -1;
      }

      if (lseek(fd, (off_t)sizeof(struct magic), SEEK_SET)
          != sizeof(struct magic)) {
            file_error(ms, errno, "error seeking `%s'", dbname);
            return -1;
      }

      if (write(fd, *magicp, (sizeof(struct magic) * *nmagicp)) 
          != (ssize_t)(sizeof(struct magic) * *nmagicp)) {
            file_error(ms, errno, "error writing `%s'", dbname);
            return -1;
      }

      (void)close(fd);
      return 0;
}

private const char ext[] = ".mgc";
/*
 * make a dbname
 */
private char *
mkdbname(const char *fn, char *buf, size_t bufsiz, int strip)
{
      if (strip) {
            const char *p;
            if ((p = strrchr(fn, '/')) != NULL)
                  fn = ++p;
      }

      (void)snprintf(buf, bufsiz, "%s%s", fn, ext);
      return buf;
}

/*
 * Byteswap an mmap'ed file if needed
 */
private void
byteswap(struct magic *magic, uint32_t nmagic)
{
      uint32_t i;
      for (i = 0; i < nmagic; i++)
            bs1(&magic[i]);
}

/*
 * swap a short
 */
private uint16_t
swap2(uint16_t sv)
{
      uint16_t rv;
      uint8_t *s = (uint8_t *)(void *)&sv; 
      uint8_t *d = (uint8_t *)(void *)&rv; 
      d[0] = s[1];
      d[1] = s[0];
      return rv;
}

/*
 * swap an int
 */
private uint32_t
swap4(uint32_t sv)
{
      uint32_t rv;
      uint8_t *s = (uint8_t *)(void *)&sv; 
      uint8_t *d = (uint8_t *)(void *)&rv; 
      d[0] = s[3];
      d[1] = s[2];
      d[2] = s[1];
      d[3] = s[0];
      return rv;
}

/*
 * byteswap a single magic entry
 */
private void
bs1(struct magic *m)
{
      m->cont_level = swap2(m->cont_level);
      m->offset = swap4((uint32_t)m->offset);
      m->in_offset = swap4((uint32_t)m->in_offset);
      if (IS_STRING(m->type))
            m->value.l = swap4(m->value.l);
      m->mask = swap4(m->mask);
}

Generated by  Doxygen 1.6.0   Back to index