mod_mime_magic.c

apache简化版

		    MODNAME ": broken symlink (%s)", fn);
	return HTTP_INTERNAL_SERVER_ERROR;
#endif
#ifdef    S_IFSOCK
#ifndef __COHERENT__
    case S_IFSOCK:
	magic_rsl_puts(r, MIME_BINARY_UNKNOWN);
	return DONE;
#endif
#endif
    case S_IFREG:
	break;
    default:
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
		    MODNAME ": invalid mode 0%o.", (unsigned int)r->finfo.st_mode);
	return HTTP_INTERNAL_SERVER_ERROR;
    }

    /*
     * regular file, check next possibility
     */
    if (r->finfo.st_size == 0) {
	magic_rsl_puts(r, MIME_TEXT_UNKNOWN);
	return DONE;
    }
    return OK;
}

/*
 * softmagic - lookup one file in database (already read from /etc/magic by
 * apprentice.c). Passed the name and FILE * of one file to be typed.
 */
		/* ARGSUSED1 *//* nbytes passed for regularity, maybe need later */
static int softmagic(request_rec *r, unsigned char *buf, int nbytes)
{
    if (match(r, 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.
 */
static int match(request_rec *r, unsigned char *s, int nbytes)
{
#if MIME_MAGIC_DEBUG
    int rule_counter = 0;
#endif
    int cont_level = 0;
    int need_separator = 0;
    union VALUETYPE p;
    magic_server_config_rec *conf = (magic_server_config_rec *)
		ap_get_module_config(r->server->module_config, &mime_magic_module);
    struct magic *m;

#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		MODNAME ": match conf=%x file=%s m=%s m->next=%s last=%s",
		conf,
		conf->magicfile ? conf->magicfile : "NULL",
		conf->magic ? "set" : "NULL",
		(conf->magic && conf->magic->next) ? "set" : "NULL",
		conf->last ? "set" : "NULL");
#endif

#if MIME_MAGIC_DEBUG
    for (m = conf->magic; m; m = m->next) {
	if (ap_isprint((((unsigned long) m) >> 24) & 255) &&
	    ap_isprint((((unsigned long) m) >> 16) & 255) &&
	    ap_isprint((((unsigned long) m) >> 8) & 255) &&
	    ap_isprint(((unsigned long) m) & 255)) {
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			MODNAME ": match: POINTER CLOBBERED! "
			"m=\"%c%c%c%c\"",
			(((unsigned long) m) >> 24) & 255,
			(((unsigned long) m) >> 16) & 255,
			(((unsigned long) m) >> 8) & 255,
			((unsigned long) m) & 255);
	    break;
	}
    }
#endif

    for (m = conf->magic; m; m = m->next) {
#if MIME_MAGIC_DEBUG
	rule_counter++;
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    MODNAME ": line=%d desc=%s", m->lineno, m->desc);
#endif

	/* check if main entry matches */
	if (!mget(r, &p, s, m, nbytes) ||
	    !mcheck(r, &p, m)) {
	    struct magic *m_cont;

	    /*
	     * main entry didn't match, flush its continuations
	     */
	    if (!m->next || (m->next->cont_level == 0)) {
		continue;
	    }

	    m_cont = m->next;
	    while (m_cont && (m_cont->cont_level != 0)) {
#if MIME_MAGIC_DEBUG
		rule_counter++;
		ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			MODNAME ": line=%d mc=%x mc->next=%x cont=%d desc=%s",
			    m_cont->lineno, m_cont,
			    m_cont->next, m_cont->cont_level,
			    m_cont->desc);
#endif
		/*
		 * this trick allows us to keep *m in sync when the continue
		 * advances the pointer
		 */
		m = m_cont;
		m_cont = m_cont->next;
	    }
	    continue;
	}

	/* if we get here, the main entry rule was a match */
	/* this will be the last run through the loop */
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    MODNAME ": rule matched, line=%d type=%d %s",
		    m->lineno, m->type,
		    (m->type == STRING) ? m->value.s : "");
#endif

	/* print the match */
	mprint(r, &p, m);

	/*
	 * If we printed something, we'll need to print a blank before we
	 * print something else.
	 */
	if (m->desc[0])
	    need_separator = 1;
	/* and any continuations that match */
	cont_level++;
	/*
	 * while (m && m->next && m->next->cont_level != 0 && ( m = m->next
	 * ))
	 */
	m = m->next;
	while (m && (m->cont_level != 0)) {
#if MIME_MAGIC_DEBUG
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			MODNAME ": match line=%d cont=%d type=%d %s",
			m->lineno, m->cont_level, m->type,
			(m->type == STRING) ? m->value.s : "");
#endif
	    if (cont_level >= m->cont_level) {
		if (cont_level > m->cont_level) {
		    /*
		     * We're at the end of the level "cont_level"
		     * continuations.
		     */
		    cont_level = m->cont_level;
		}
		if (mget(r, &p, s, m, nbytes) &&
		    mcheck(r, &p, m)) {
		    /*
		     * 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
			&& (m->nospflag == 0)
			&& (m->desc[0] != '\0')
			) {
			(void) magic_rsl_putchar(r, ' ');
			need_separator = 0;
		    }
		    mprint(r, &p, m);
		    if (m->desc[0])
			need_separator = 1;

		    /*
		     * If we see any continuations at a higher level, process
		     * them.
		     */
		    cont_level++;
		}
	    }

	    /* move to next continuation record */
	    m = m->next;
	}
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    MODNAME ": matched after %d rules", rule_counter);
#endif
	return 1;		/* all through */
    }
#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		MODNAME ": failed after %d rules", rule_counter);
#endif
    return 0;			/* no match at all */
}

static void mprint(request_rec *r, union VALUETYPE *p, struct magic *m)
{
    char *pp, *rt;
    unsigned long v;

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

    case SHORT:
    case BESHORT:
    case LESHORT:
	v = p->h;
	break;

    case LONG:
    case BELONG:
    case LELONG:
	v = p->l;
	break;

    case STRING:
	if (m->reln == '=') {
	    (void) magic_rsl_printf(r, m->desc, m->value.s);
	}
	else {
	    (void) magic_rsl_printf(r, m->desc, p->s);
	}
	return;

    case DATE:
    case BEDATE:
    case LEDATE:
	/* XXX: not multithread safe */
	pp = ctime((time_t *) & p->l);
	if ((rt = strchr(pp, '\n')) != NULL)
	    *rt = '\0';
	(void) magic_rsl_printf(r, m->desc, pp);
	return;
    default:
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
		    MODNAME ": invalid m->type (%d) in mprint().",
		    m->type);
	return;
    }

    v = signextend(r->server, m, v) & m->mask;
    (void) magic_rsl_printf(r, m->desc, (unsigned long) v);
}

/*
 * Convert the byte order of the data we are looking at
 */
static int mconvert(request_rec *r, union VALUETYPE *p, struct magic *m)
{
    char *rt;

    switch (m->type) {
    case BYTE:
    case SHORT:
    case LONG:
    case DATE:
	return 1;
    case STRING:
	/* Null terminate and eat the return */
	p->s[sizeof(p->s) - 1] = '\0';
	if ((rt = strchr(p->s, '\n')) != NULL)
	    *rt = '\0';
	return 1;
    case BESHORT:
	p->h = (short) ((p->hs[0] << 8) | (p->hs[1]));
	return 1;
    case BELONG:
    case BEDATE:
	p->l = (long)
	    ((p->hl[0] << 24) | (p->hl[1] << 16) | (p->hl[2] << 8) | (p->hl[3]));
	return 1;
    case LESHORT:
	p->h = (short) ((p->hs[1] << 8) | (p->hs[0]));
	return 1;
    case LELONG:
    case LEDATE:
	p->l = (long)
	    ((p->hl[3] << 24) | (p->hl[2] << 16) | (p->hl[1] << 8) | (p->hl[0]));
	return 1;
    default:
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
		    MODNAME ": invalid type %d in mconvert().", m->type);
	return 0;
    }
}


static int mget(request_rec *r, union VALUETYPE *p, unsigned char *s,
		struct magic *m, int nbytes)
{
    long offset = m->offset;

    if (offset + sizeof(union VALUETYPE) > nbytes)
	          return 0;

    memcpy(p, s + offset, sizeof(union VALUETYPE));

    if (!mconvert(r, p, m))
	return 0;

    if (m->flag & INDIR) {

	switch (m->in.type) {
	case BYTE:
	    offset = p->b + m->in.offset;
	    break;
	case SHORT:
	    offset = p->h + m->in.offset;
	    break;
	case LONG:
	    offset = p->l + m->in.offset;
	    break;
	}

	if (offset + sizeof(union VALUETYPE) > nbytes)
	              return 0;

	memcpy(p, s + offset, sizeof(union VALUETYPE));

	if (!mconvert(r, p, m))
	    return 0;
    }
    return 1;
}

static int mcheck(request_rec *r, union VALUETYPE *p, struct magic *m)
{
    register unsigned long l = m->value.l;
    register unsigned long v;
    int matched;

    if ((m->value.s[0] == 'x') && (m->value.s[1] == '\0')) {
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
		    MODNAME ": BOINK");
	return 1;
    }

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

    case SHORT:
    case BESHORT:
    case LESHORT:
	v = p->h;
	break;

    case LONG:
    case BELONG:
    case LELONG:
    case DATE:
    case BEDATE:
    case LEDATE:
	v = p->l;
	break;

    case STRING:
	l = 0;
	/*
	 * 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.
	 */
	v = 0;
	{
	    register unsigned char *a = (unsigned char *) m->value.s;
	    register unsigned char *b = (unsigned char *) p->s;
	    register int len = m->vallen;

	    while (--len >= 0)
		if ((v = *b++ - *a++) != 0)
		    break;
	}
	break;
    default:
	/*  bogosity, pretend that it just wasn't a match */
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
		    MODNAME ": invalid type %d in mcheck().", m->type);
	return 0;
    }

    v = signextend(r->server, m, v) & m->mask;

    switch (m->reln) {
    case 'x':
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    "%lu == *any* = 1", v);
#endif
	matched = 1;
	break;

    case '!':
	matched = v != l;
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    "%lu != %lu = %d", v, l, matched);
#endif
	break;

    case '=':
	matched = v == l;
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    "%lu == %lu = %d", v, l, matched);
#endif
	break;

    case '>':
	if (m->flag & UNSIGNED) {
	    matched = v > l;
#if MIME_MAGIC_DEBUG
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			"%lu > %lu = %d", v, l, matched);
#endif
	}
	else {
	    matched = (long) v > (long) l;
#if MIME_MAGIC_DEBUG
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			"%ld > %ld = %d", v, l, matched);
#endif
	}
	break;

    case '<':
	if (m->flag & UNSIGNED) {
	    matched = v < l;
#if MIME_MAGIC_DEBUG
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			"%lu < %lu = %d", v, l, matched);
#endif
	}
	else {
	    matched = (long) v < (long) l;
#if MIME_MAGIC_DEBUG
	    ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
			"%ld < %ld = %d", v, l, matched);
#endif
	}
	break;

    case '&':
	matched = (v & l) == l;
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    "((%lx & %lx) == %lx) = %d", v, l, l, matched);
#endif
	break;

    case '^':
	matched = (v & l) != l;
#if MIME_MAGIC_DEBUG
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_DEBUG, r,
		    "((%lx & %lx) != %lx) = %d", v, l, l, matched);
#endif
	break;