root/modules/metadata/mod_mime_magic.c

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DEFINITIONS

This source file includes following definitions.
  1. create_magic_server_config
  2. merge_magic_server_config
  3. set_magicfile
  4. magic_set_config
  5. magic_rsl_add
  6. magic_rsl_puts
  7. magic_rsl_printf
  8. magic_rsl_putchar
  9. rsl_strdup
  10. magic_rsl_to_request
  11. magic_process
  12. tryit
  13. apprentice
  14. signextend
  15. parse
  16. getvalue
  17. getstr
  18. hextoint
  19. fsmagic
  20. softmagic
  21. match
  22. mprint
  23. mconvert
  24. mget
  25. mcheck
  26. ascmagic
  27. zmagic
  28. create_uncompress_child
  29. uncompress
  30. is_tar
  31. from_oct
  32. revision_suffix
  33. magic_init
  34. magic_find_ct
  35. register_hooks

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * mod_mime_magic: MIME type lookup via file magic numbers
 * Copyright (c) 1996-1997 Cisco Systems, Inc.
 *
 * This software was submitted by Cisco Systems to the Apache Software Foundation in July
 * 1997.  Future revisions and derivatives of this source code must
 * acknowledge Cisco Systems as the original contributor of this module.
 * All other licensing and usage conditions are those of the Apache Software Foundation.
 *
 * Some of this code is derived from the free version of the file command
 * originally posted to comp.sources.unix.  Copyright info for that program
 * is included below as required.
 * ---------------------------------------------------------------------------
 * - Copyright (c) Ian F. Darwin, 1987. Written by Ian F. Darwin.
 *
 * This software is not subject to any license of the American Telephone and
 * Telegraph Company or of the Regents of the University of California.
 *
 * Permission is granted to anyone to use this software for any purpose on any
 * computer system, and to alter it and redistribute it freely, subject to
 * the following restrictions:
 *
 * 1. The author is not responsible for the consequences of use of this
 * software, no matter how awful, even if they arise from flaws in it.
 *
 * 2. The origin of this software must not be misrepresented, either by
 * explicit claim or by omission.  Since few users ever read sources, credits
 * must appear in the documentation.
 *
 * 3. Altered versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.  Since few users ever read
 * sources, credits must appear in the documentation.
 *
 * 4. This notice may not be removed or altered.
 * -------------------------------------------------------------------------
 *
 * For compliance with Mr Darwin's terms: this has been very significantly
 * modified from the free "file" command.
 * - all-in-one file for compilation convenience when moving from one
 *   version of Apache to the next.
 * - Memory allocation is done through the Apache API's apr_pool_t structure.
 * - All functions have had necessary Apache API request or server
 *   structures passed to them where necessary to call other Apache API
 *   routines.  (i.e. usually for logging, files, or memory allocation in
 *   itself or a called function.)
 * - struct magic has been converted from an array to a single-ended linked
 *   list because it only grows one record at a time, it's only accessed
 *   sequentially, and the Apache API has no equivalent of realloc().
 * - Functions have been changed to get their parameters from the server
 *   configuration instead of globals.  (It should be reentrant now but has
 *   not been tested in a threaded environment.)
 * - Places where it used to print results to stdout now saves them in a
 *   list where they're used to set the MIME type in the Apache request
 *   record.
 * - Command-line flags have been removed since they will never be used here.
 *
 * Ian Kluft <ikluft@cisco.com>
 * Engineering Information Framework
 * Central Engineering
 * Cisco Systems, Inc.
 * San Jose, CA, USA
 *
 * Initial installation          July/August 1996
 * Misc bug fixes                May 1997
 * Submission to Apache Software Foundation    July 1997
 *
 */

#include "apr.h"
#include "apr_strings.h"
#include "apr_lib.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"

#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#include "http_core.h"
#include "http_log.h"
#include "http_protocol.h"
#include "util_script.h"

/* ### this isn't set by configure? does anybody set this? */
#ifdef HAVE_UTIME_H
#include <utime.h>
#endif

/*
 * data structures and related constants
 */

#define MODNAME        "mod_mime_magic"
#define MIME_MAGIC_DEBUG        0

#define MIME_BINARY_UNKNOWN    "application/octet-stream"
#define MIME_TEXT_UNKNOWN    "text/plain"

#define MAXMIMESTRING        256

/* HOWMANY must be at least 4096 to make gzip -dcq work */
#define HOWMANY  4096
/* SMALL_HOWMANY limits how much work we do to figure out text files */
#define SMALL_HOWMANY 1024
#define MAXDESC    50   /* max leng of text description */
#define MAXstring 64    /* max leng of "string" types */

struct magic {
    struct magic *next;     /* link to next entry */
    int lineno;             /* line number from magic file */

    short flag;
#define INDIR  1            /* if '>(...)' appears,  */
#define UNSIGNED 2          /* comparison is unsigned */
    short cont_level;       /* level of ">" */
    struct {
        char type;          /* byte short long */
        long offset;        /* offset from indirection */
    } in;
    long offset;            /* offset to magic number */
    unsigned char reln;     /* relation (0=eq, '>'=gt, etc) */
    char type;              /* int, short, long or string. */
    char vallen;            /* length of string value, if any */
#define BYTE      1
#define SHORT     2
#define LONG      4
#define STRING    5
#define DATE      6
#define BESHORT   7
#define BELONG    8
#define BEDATE    9
#define LESHORT  10
#define LELONG   11
#define LEDATE   12
    union VALUETYPE {
        unsigned char b;
        unsigned short h;
        unsigned long l;
        char s[MAXstring];
        unsigned char hs[2];   /* 2 bytes of a fixed-endian "short" */
        unsigned char hl[4];   /* 2 bytes of a fixed-endian "long" */
    } value;                   /* either number or string */
    unsigned long mask;        /* mask before comparison with value */
    char nospflag;             /* supress space character */

    /* NOTE: this string is suspected of overrunning - find it! */
    char desc[MAXDESC];        /* description */
};

/*
 * data structures for tar file recognition
 * --------------------------------------------------------------------------
 * Header file for public domain tar (tape archive) program.
 *
 * @(#)tar.h 1.20 86/10/29    Public Domain. Created 25 August 1985 by John
 * Gilmore, ihnp4!hoptoad!gnu.
 *
 * Header block on tape.
 *
 * I'm going to use traditional DP naming conventions here. A "block" is a big
 * chunk of stuff that we do I/O on. A "record" is a piece of info that we
 * care about. Typically many "record"s fit into a "block".
 */
#define RECORDSIZE    512
#define NAMSIZ    100
#define TUNMLEN    32
#define TGNMLEN    32

union record {
    char charptr[RECORDSIZE];
    struct header {
        char name[NAMSIZ];
        char mode[8];
        char uid[8];
        char gid[8];
        char size[12];
        char mtime[12];
        char chksum[8];
        char linkflag;
        char linkname[NAMSIZ];
        char magic[8];
        char uname[TUNMLEN];
        char gname[TGNMLEN];
        char devmajor[8];
        char devminor[8];
    } header;
};

/* The magic field is filled with this if uname and gname are valid. */
#define    TMAGIC        "ustar  "   /* 7 chars and a null */

/*
 * file-function prototypes
 */
static int ascmagic(request_rec *, unsigned char *, apr_size_t);
static int is_tar(unsigned char *, apr_size_t);
static int softmagic(request_rec *, unsigned char *, apr_size_t);
static int tryit(request_rec *, unsigned char *, apr_size_t, int);
static int zmagic(request_rec *, unsigned char *, apr_size_t);

static int getvalue(server_rec *, struct magic *, char **);
static int hextoint(int);
static char *getstr(server_rec *, char *, char *, int, int *);
static int parse(server_rec *, apr_pool_t *p, char *, int);

static int match(request_rec *, unsigned char *, apr_size_t);
static int mget(request_rec *, union VALUETYPE *, unsigned char *,
                struct magic *, apr_size_t);
static int mcheck(request_rec *, union VALUETYPE *, struct magic *);
static void mprint(request_rec *, union VALUETYPE *, struct magic *);

static int uncompress(request_rec *, int,
                      unsigned char **, apr_size_t);
static long from_oct(int, char *);
static int fsmagic(request_rec *r, const char *fn);

/*
 * includes for ASCII substring recognition formerly "names.h" in file
 * command
 *
 * Original notes: names and types used by ascmagic in file(1). These tokens are
 * here because they can appear anywhere in the first HOWMANY bytes, while
 * tokens in /etc/magic must appear at fixed offsets into the file. Don't
 * make HOWMANY too high unless you have a very fast CPU.
 */

/* these types are used to index the apr_table_t 'types': keep em in sync! */
/* HTML inserted in first because this is a web server module now */
#define L_HTML    0   /* HTML */
#define L_C       1   /* first and foremost on UNIX */
#define L_FORT    2   /* the oldest one */
#define L_MAKE    3   /* Makefiles */
#define L_PLI     4   /* PL/1 */
#define L_MACH    5   /* some kinda assembler */
#define L_ENG     6   /* English */
#define L_PAS     7   /* Pascal */
#define L_MAIL    8   /* Electronic mail */
#define L_NEWS    9   /* Usenet Netnews */

static char *types[] =
{
    "text/html",             /* HTML */
    "text/plain",            /* "c program text", */
    "text/plain",            /* "fortran program text", */
    "text/plain",            /* "make commands text", */
    "text/plain",            /* "pl/1 program text", */
    "text/plain",            /* "assembler program text", */
    "text/plain",            /* "English text", */
    "text/plain",            /* "pascal program text", */
    "message/rfc822",        /* "mail text", */
    "message/news",          /* "news text", */
    "application/binary",    /* "can't happen error on names.h/types", */
    0
};

static struct names {
    char *name;
    short type;
} names[] = {

    /* These must be sorted by eye for optimal hit rate */
    /* Add to this list only after substantial meditation */
    {
        "<html>", L_HTML
    },
    {
        "<HTML>", L_HTML
    },
    {
        "<head>", L_HTML
    },
    {
        "<HEAD>", L_HTML
    },
    {
        "<title>", L_HTML
    },
    {
        "<TITLE>", L_HTML
    },
    {
        "<h1>", L_HTML
    },
    {
        "<H1>", L_HTML
    },
    {
        "<!--", L_HTML
    },
    {
        "<!DOCTYPE HTML", L_HTML
    },
    {
        "/*", L_C
    },               /* must precede "The", "the", etc. */
    {
        "#include", L_C
    },
    {
        "char", L_C
    },
    {
        "The", L_ENG
    },
    {
        "the", L_ENG
    },
    {
        "double", L_C
    },
    {
        "extern", L_C
    },
    {
        "float", L_C
    },
    {
        "real", L_C
    },
    {
        "struct", L_C
    },
    {
        "union", L_C
    },
    {
        "CFLAGS", L_MAKE
    },
    {
        "LDFLAGS", L_MAKE
    },
    {
        "all:", L_MAKE
    },
    {
        ".PRECIOUS", L_MAKE
    },
    /*
     * Too many files of text have these words in them.  Find another way to
     * recognize Fortrash.
     */
#ifdef    NOTDEF
    {
        "subroutine", L_FORT
    },
    {
        "function", L_FORT
    },
    {
        "block", L_FORT
    },
    {
        "common", L_FORT
    },
    {
        "dimension", L_FORT
    },
    {
        "integer", L_FORT
    },
    {
        "data", L_FORT
    },
#endif /* NOTDEF */
    {
        ".ascii", L_MACH
    },
    {
        ".asciiz", L_MACH
    },
    {
        ".byte", L_MACH
    },
    {
        ".even", L_MACH
    },
    {
        ".globl", L_MACH
    },
    {
        "clr", L_MACH
    },
    {
        "(input,", L_PAS
    },
    {
        "dcl", L_PLI
    },
    {
        "Received:", L_MAIL
    },
    {
        ">From", L_MAIL
    },
    {
        "Return-Path:", L_MAIL
    },
    {
        "Cc:", L_MAIL
    },
    {
        "Newsgroups:", L_NEWS
    },
    {
        "Path:", L_NEWS
    },
    {
        "Organization:", L_NEWS
    },
    {
        NULL, 0
    }
};

#define NNAMES ((sizeof(names)/sizeof(struct names)) - 1)

/*
 * Result String List (RSL)
 *
 * The file(1) command prints its output.  Instead, we store the various
 * "printed" strings in a list (allocating memory as we go) and concatenate
 * them at the end when we finally know how much space they'll need.
 */

typedef struct magic_rsl_s {
    char *str;                  /* string, possibly a fragment */
    struct magic_rsl_s *next;   /* pointer to next fragment */
} magic_rsl;

/*
 * Apache module configuration structures
 */

/* per-server info */
typedef struct {
    const char *magicfile;    /* where magic be found */
    struct magic *magic;      /* head of magic config list */
    struct magic *last;
} magic_server_config_rec;

/* per-request info */
typedef struct {
    magic_rsl *head;          /* result string list */
    magic_rsl *tail;
    unsigned suf_recursion;   /* recursion depth in suffix check */
} magic_req_rec;

/*
 * configuration functions - called by Apache API routines
 */

module AP_MODULE_DECLARE_DATA mime_magic_module;

static void *create_magic_server_config(apr_pool_t *p, server_rec *d)
{
    /* allocate the config - use pcalloc because it needs to be zeroed */
    return apr_pcalloc(p, sizeof(magic_server_config_rec));
}

static void *merge_magic_server_config(apr_pool_t *p, void *basev, void *addv)
{
    magic_server_config_rec *base = (magic_server_config_rec *) basev;
    magic_server_config_rec *add = (magic_server_config_rec *) addv;
    magic_server_config_rec *new = (magic_server_config_rec *)
                            apr_palloc(p, sizeof(magic_server_config_rec));

    new->magicfile = add->magicfile ? add->magicfile : base->magicfile;
    new->magic = NULL;
    new->last = NULL;
    return new;
}

static const char *set_magicfile(cmd_parms *cmd, void *dummy, const char *arg)
{
    magic_server_config_rec *conf = (magic_server_config_rec *)
    ap_get_module_config(cmd->server->module_config,
                      &mime_magic_module);

    if (!conf) {
        return MODNAME ": server structure not allocated";
    }
    conf->magicfile = arg;
    return NULL;
}

/*
 * configuration file commands - exported to Apache API
 */

static const command_rec mime_magic_cmds[] =
{
    AP_INIT_TAKE1("MimeMagicFile", set_magicfile, NULL, RSRC_CONF,
     "Path to MIME Magic file (in file(1) format)"),
    {NULL}
};

/*
 * RSL (result string list) processing routines
 *
 * These collect strings that would have been printed in fragments by file(1)
 * into a list of magic_rsl structures with the strings. When complete,
 * they're concatenated together to become the MIME content and encoding
 * types.
 *
 * return value conventions for these functions: functions which return int:
 * failure = -1, other = result functions which return pointers: failure = 0,
 * other = result
 */

/* allocate a per-request structure and put it in the request record */
static magic_req_rec *magic_set_config(request_rec *r)
{
    magic_req_rec *req_dat = (magic_req_rec *) apr_palloc(r->pool,
                                                      sizeof(magic_req_rec));

    req_dat->head = req_dat->tail = (magic_rsl *) NULL;
    ap_set_module_config(r->request_config, &mime_magic_module, req_dat);
    return req_dat;
}

/* add a string to the result string list for this request */
/* it is the responsibility of the caller to allocate "str" */
static int magic_rsl_add(request_rec *r, char *str)
{
    magic_req_rec *req_dat = (magic_req_rec *)
                    ap_get_module_config(r->request_config, &mime_magic_module);
    magic_rsl *rsl;

    /* make sure we have a list to put it in */
    if (!req_dat) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EINVAL, r,
                    MODNAME ": request config should not be NULL");
        if (!(req_dat = magic_set_config(r))) {
            /* failure */
            return -1;
        }
    }

    /* allocate the list entry */
    rsl = (magic_rsl *) apr_palloc(r->pool, sizeof(magic_rsl));

    /* fill it */
    rsl->str = str;
    rsl->next = (magic_rsl *) NULL;

    /* append to the list */
    if (req_dat->head && req_dat->tail) {
        req_dat->tail->next = rsl;
        req_dat->tail = rsl;
    }
    else {
        req_dat->head = req_dat->tail = rsl;
    }

    /* success */
    return 0;
}

/* RSL hook for puts-type functions */
static int magic_rsl_puts(request_rec *r, char *str)
{
    return magic_rsl_add(r, str);
}

/* RSL hook for printf-type functions */
static int magic_rsl_printf(request_rec *r, char *str,...)
{
    va_list ap;

    char buf[MAXMIMESTRING];

    /* assemble the string into the buffer */
    va_start(ap, str);
    apr_vsnprintf(buf, sizeof(buf), str, ap);
    va_end(ap);

    /* add the buffer to the list */
    return magic_rsl_add(r, apr_pstrdup(r->pool, buf));
}

/* RSL hook for putchar-type functions */
static int magic_rsl_putchar(request_rec *r, char c)
{
    char str[2];

    /* high overhead for 1 char - just hope they don't do this much */
    str[0] = c;
    str[1] = '\0';
    return magic_rsl_add(r, str);
}

/* allocate and copy a contiguous string from a result string list */
static char *rsl_strdup(request_rec *r, int start_frag, int start_pos, int len)
{
    char *result;       /* return value */
    int cur_frag,       /* current fragment number/counter */
        cur_pos,        /* current position within fragment */
        res_pos;        /* position in result string */
    magic_rsl *frag;    /* list-traversal pointer */
    magic_req_rec *req_dat = (magic_req_rec *)
                    ap_get_module_config(r->request_config, &mime_magic_module);

    /* allocate the result string */
    result = (char *) apr_palloc(r->pool, len + 1);

    /* loop through and collect the string */
    res_pos = 0;
    for (frag = req_dat->head, cur_frag = 0;
         frag->next;
         frag = frag->next, cur_frag++) {
        /* loop to the first fragment */
        if (cur_frag < start_frag)
            continue;

        /* loop through and collect chars */
        for (cur_pos = (cur_frag == start_frag) ? start_pos : 0;
             frag->str[cur_pos];
             cur_pos++) {
            if (cur_frag >= start_frag
                && cur_pos >= start_pos
                && res_pos <= len) {
                result[res_pos++] = frag->str[cur_pos];
                if (res_pos > len) {
                    break;
                }
            }
        }
    }

    /* clean up and return */
    result[res_pos] = 0;
#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
             MODNAME ": rsl_strdup() %d chars: %s", res_pos - 1, result);
#endif
    return result;
}

/* states for the state-machine algorithm in magic_rsl_to_request() */
typedef enum {
    rsl_leading_space, rsl_type, rsl_subtype, rsl_separator, rsl_encoding
} rsl_states;

/* process the RSL and set the MIME info in the request record */
static int magic_rsl_to_request(request_rec *r)
{
    int cur_frag,         /* current fragment number/counter */
        cur_pos,          /* current position within fragment */
        type_frag,        /* content type starting point: fragment */
        type_pos,         /* content type starting point: position */
        type_len,         /* content type length */
        encoding_frag,    /* content encoding starting point: fragment */
        encoding_pos,     /* content encoding starting point: position */
        encoding_len;     /* content encoding length */

    magic_rsl *frag;      /* list-traversal pointer */
    rsl_states state;

    magic_req_rec *req_dat = (magic_req_rec *)
                    ap_get_module_config(r->request_config, &mime_magic_module);

    /* check if we have a result */
    if (!req_dat || !req_dat->head) {
        /* empty - no match, we defer to other Apache modules */
        return DECLINED;
    }

    /* start searching for the type and encoding */
    state = rsl_leading_space;
    type_frag = type_pos = type_len = 0;
    encoding_frag = encoding_pos = encoding_len = 0;
    for (frag = req_dat->head, cur_frag = 0;
         frag && frag->next;
         frag = frag->next, cur_frag++) {
        /* loop through the characters in the fragment */
        for (cur_pos = 0; frag->str[cur_pos]; cur_pos++) {
            if (apr_isspace(frag->str[cur_pos])) {
                /* process whitespace actions for each state */
                if (state == rsl_leading_space) {
                    /* eat whitespace in this state */
                    continue;
                }
                else if (state == rsl_type) {
                    /* whitespace: type has no slash! */
                    return DECLINED;
                }
                else if (state == rsl_subtype) {
                    /* whitespace: end of MIME type */
                    state++;
                    continue;
                }
                else if (state == rsl_separator) {
                    /* eat whitespace in this state */
                    continue;
                }
                else if (state == rsl_encoding) {
                    /* whitespace: end of MIME encoding */
                    /* we're done */
                    frag = req_dat->tail;
                    break;
                }
                else {
                    /* should not be possible */
                    /* abandon malfunctioning module */
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                                MODNAME ": bad state %d (ws)", state);
                    return DECLINED;
                }
                /* NOTREACHED */
            }
            else if (state == rsl_type &&
                     frag->str[cur_pos] == '/') {
                /* copy the char and go to rsl_subtype state */
                type_len++;
                state++;
            }
            else {
                /* process non-space actions for each state */
                if (state == rsl_leading_space) {
                    /* non-space: begin MIME type */
                    state++;
                    type_frag = cur_frag;
                    type_pos = cur_pos;
                    type_len = 1;
                    continue;
                }
                else if (state == rsl_type ||
                         state == rsl_subtype) {
                    /* non-space: adds to type */
                    type_len++;
                    continue;
                }
                else if (state == rsl_separator) {
                    /* non-space: begin MIME encoding */
                    state++;
                    encoding_frag = cur_frag;
                    encoding_pos = cur_pos;
                    encoding_len = 1;
                    continue;
                }
                else if (state == rsl_encoding) {
                    /* non-space: adds to encoding */
                    encoding_len++;
                    continue;
                }
                else {
                    /* should not be possible */
                    /* abandon malfunctioning module */
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                                MODNAME ": bad state %d (ns)", state);
                    return DECLINED;
                }
                /* NOTREACHED */
            }
            /* NOTREACHED */
        }
    }

    /* if we ended prior to state rsl_subtype, we had incomplete info */
    if (state != rsl_subtype && state != rsl_separator &&
        state != rsl_encoding) {
        /* defer to other modules */
        return DECLINED;
    }

    /* save the info in the request record */
    if (state == rsl_subtype || state == rsl_encoding ||
        state == rsl_encoding) {
        char *tmp;
        tmp = rsl_strdup(r, type_frag, type_pos, type_len);
        /* XXX: this could be done at config time I'm sure... but I'm
         * confused by all this magic_rsl stuff. -djg */
        ap_content_type_tolower(tmp);
        ap_set_content_type(r, tmp);
    }
    if (state == rsl_encoding) {
        char *tmp;
        tmp = rsl_strdup(r, encoding_frag,
                                         encoding_pos, encoding_len);
        /* XXX: this could be done at config time I'm sure... but I'm
         * confused by all this magic_rsl stuff. -djg */
        ap_str_tolower(tmp);
        r->content_encoding = tmp;
    }

    /* detect memory allocation or other errors */
    if (!r->content_type ||
        (state == rsl_encoding && !r->content_encoding)) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      MODNAME ": unexpected state %d; could be caused by bad "
                      "data in magic file",
                      state);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* success! */
    return OK;
}

/*
 * magic_process - process input file r        Apache API request record
 * (formerly called "process" in file command, prefix added for clarity) Opens
 * the file and reads a fixed-size buffer to begin processing the contents.
 */
static int magic_process(request_rec *r)
{
    apr_file_t *fd = NULL;
    unsigned char buf[HOWMANY + 1];  /* one extra for terminating '\0' */
    apr_size_t nbytes = 0;           /* number of bytes read from a datafile */
    int result;

    /*
     * first try judging the file based on its filesystem status
     */
    switch ((result = fsmagic(r, r->filename))) {
    case DONE:
        magic_rsl_putchar(r, '\n');
        return OK;
    case OK:
        break;
    default:
        /* fatal error, bail out */
        return result;
    }

    if (apr_file_open(&fd, r->filename, APR_READ, APR_OS_DEFAULT, r->pool) != APR_SUCCESS) {
        /* We can't open it, but we were able to stat it. */
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                    MODNAME ": can't read `%s'", r->filename);
        /* let some other handler decide what the problem is */
        return DECLINED;
    }

    /*
     * try looking at the first HOWMANY bytes
     */
    nbytes = sizeof(buf) - 1;
    if ((result = apr_file_read(fd, (char *) buf, &nbytes)) != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, result, r,
                    MODNAME ": read failed: %s", r->filename);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    if (nbytes == 0) {
        return DECLINED;
    }
    else {
        buf[nbytes++] = '\0';  /* null-terminate it */
        result = tryit(r, buf, nbytes, 1);
        if (result != OK) {
            return result;
        }
    }

    (void) apr_file_close(fd);
    (void) magic_rsl_putchar(r, '\n');

    return OK;
}


static int tryit(request_rec *r, unsigned char *buf, apr_size_t nb,
                 int checkzmagic)
{
    /*
     * Try compression stuff
     */
        if (checkzmagic == 1) {
                        if (zmagic(r, buf, nb) == 1)
                        return OK;
        }

    /*
     * try tests in /etc/magic (or surrogate magic file)
     */
    if (softmagic(r, buf, nb) == 1)
        return OK;

    /*
     * try known keywords, check for ascii-ness too.
     */
    if (ascmagic(r, buf, nb) == 1)
        return OK;

    /*
     * abandon hope, all ye who remain here
     */
    return DECLINED;
}

#define    EATAB {while (apr_isspace(*l))  ++l;}

/*
 * apprentice - load configuration from the magic file r
 *  API request record
 */
static int apprentice(server_rec *s, apr_pool_t *p)
{
    apr_file_t *f = NULL;
    apr_status_t result;
    char line[BUFSIZ + 1];
    int errs = 0;
    int lineno;
#if MIME_MAGIC_DEBUG
    int rule = 0;
    struct magic *m, *prevm;
#endif
    magic_server_config_rec *conf = (magic_server_config_rec *)
                    ap_get_module_config(s->module_config, &mime_magic_module);
    const char *fname = ap_server_root_relative(p, conf->magicfile);

    if (!fname) {
        ap_log_error(APLOG_MARK, APLOG_ERR, APR_EBADPATH, s,
                     MODNAME ": Invalid magic file path %s", conf->magicfile);
        return -1;
    }
    if ((result = apr_file_open(&f, fname, APR_READ | APR_BUFFERED,
                                APR_OS_DEFAULT, p)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, result, s,
                     MODNAME ": can't read magic file %s", fname);
        return -1;
    }

    /* set up the magic list (empty) */
    conf->magic = conf->last = NULL;

    /* parse it */
    for (lineno = 1; apr_file_gets(line, BUFSIZ, f) == APR_SUCCESS; lineno++) {
        int ws_offset;
        char *last = line + strlen(line) - 1; /* guaranteed that len >= 1 since an
                                               * "empty" line contains a '\n'
                                               */

        /* delete newline and any other trailing whitespace */
        while (last >= line
               && apr_isspace(*last)) {
            *last = '\0';
            --last;
        }

        /* skip leading whitespace */
        ws_offset = 0;
        while (line[ws_offset] && apr_isspace(line[ws_offset])) {
            ws_offset++;
        }

        /* skip blank lines */
        if (line[ws_offset] == 0) {
            continue;
        }

        /* comment, do not parse */
        if (line[ws_offset] == '#')
            continue;

#if MIME_MAGIC_DEBUG
        /* if we get here, we're going to use it so count it */
        rule++;
#endif

        /* parse it */
        if (parse(s, p, line + ws_offset, lineno) != 0)
            ++errs;
    }

    (void) apr_file_close(f);

#if MIME_MAGIC_DEBUG
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice 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");
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice read %d lines, %d rules, %d errors",
                lineno, rule, errs);
#endif

#if MIME_MAGIC_DEBUG
    prevm = 0;
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice test");
    for (m = conf->magic; m; m = m->next) {
        if (apr_isprint((((unsigned long) m) >> 24) & 255) &&
            apr_isprint((((unsigned long) m) >> 16) & 255) &&
            apr_isprint((((unsigned long) m) >> 8) & 255) &&
            apr_isprint(((unsigned long) m) & 255)) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                        MODNAME ": apprentice: POINTER CLOBBERED! "
                        "m=\"%c%c%c%c\" line=%d",
                        (((unsigned long) m) >> 24) & 255,
                        (((unsigned long) m) >> 16) & 255,
                        (((unsigned long) m) >> 8) & 255,
                        ((unsigned long) m) & 255,
                        prevm ? prevm->lineno : -1);
            break;
        }
        prevm = m;
    }
#endif

    return (errs ? -1 : 0);
}

/*
 * extend the sign bit if the comparison is to be signed
 */
static unsigned long signextend(server_rec *s, struct magic *m, unsigned long 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 BYTE:
            v = (char) v;
            break;
        case SHORT:
        case BESHORT:
        case LESHORT:
            v = (short) v;
            break;
        case DATE:
        case BEDATE:
        case LEDATE:
        case LONG:
        case BELONG:
        case LELONG:
            v = (long) v;
            break;
        case STRING:
            break;
        default:
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
                        MODNAME ": can't happen: m->type=%d", m->type);
            return -1;
        }
    return v;
}

/*
 * parse one line from magic file, put into magic[index++] if valid
 */
static int parse(server_rec *serv, apr_pool_t *p, char *l, int lineno)
{
    struct magic *m;
    char *t, *s;
    magic_server_config_rec *conf = (magic_server_config_rec *)
                    ap_get_module_config(serv->module_config, &mime_magic_module);

    /* allocate magic structure entry */
    m = (struct magic *) apr_pcalloc(p, sizeof(struct magic));

    /* append to linked list */
    m->next = NULL;
    if (!conf->magic || !conf->last) {
        conf->magic = conf->last = m;
    }
    else {
        conf->last->next = m;
        conf->last = m;
    }

    /* set values in magic structure */
    m->flag = 0;
    m->cont_level = 0;
    m->lineno = lineno;

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

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

    /* get offset, then skip over it */
    m->offset = (int) strtol(l, &t, 0);
    if (l == t) {
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                    MODNAME ": offset %s invalid", l);
    }
    l = t;

    if (m->flag & INDIR) {
        m->in.type = LONG;
        m->in.offset = 0;
        /*
         * read [.lbs][+-]nnnnn)
         */
        if (*l == '.') {
            switch (*++l) {
            case 'l':
                m->in.type = LONG;
                break;
            case 's':
                m->in.type = SHORT;
                break;
            case 'b':
                m->in.type = BYTE;
                break;
            default:
                ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": indirect offset type %c invalid", *l);
                break;
            }
            l++;
        }
        s = l;
        if (*l == '+' || *l == '-')
            l++;
        if (apr_isdigit((unsigned char) *l)) {
            m->in.offset = strtol(l, &t, 0);
            if (*s == '-')
                m->in.offset = -m->in.offset;
        }
        else
            t = l;
        if (*t++ != ')') {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": missing ')' in indirect offset");
        }
        l = t;
    }


    while (apr_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

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

    /* get type, skip it */
    if (strncmp(l, "byte", NBYTE) == 0) {
        m->type = BYTE;
        l += NBYTE;
    }
    else if (strncmp(l, "short", NSHORT) == 0) {
        m->type = SHORT;
        l += NSHORT;
    }
    else if (strncmp(l, "long", NLONG) == 0) {
        m->type = LONG;
        l += NLONG;
    }
    else if (strncmp(l, "string", NSTRING) == 0) {
        m->type = STRING;
        l += NSTRING;
    }
    else if (strncmp(l, "date", NDATE) == 0) {
        m->type = DATE;
        l += NDATE;
    }
    else if (strncmp(l, "beshort", NBESHORT) == 0) {
        m->type = BESHORT;
        l += NBESHORT;
    }
    else if (strncmp(l, "belong", NBELONG) == 0) {
        m->type = BELONG;
        l += NBELONG;
    }
    else if (strncmp(l, "bedate", NBEDATE) == 0) {
        m->type = BEDATE;
        l += NBEDATE;
    }
    else if (strncmp(l, "leshort", NLESHORT) == 0) {
        m->type = LESHORT;
        l += NLESHORT;
    }
    else if (strncmp(l, "lelong", NLELONG) == 0) {
        m->type = LELONG;
        l += NLELONG;
    }
    else if (strncmp(l, "ledate", NLEDATE) == 0) {
        m->type = LEDATE;
        l += NLEDATE;
    }
    else {
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                    MODNAME ": type %s invalid", l);
        return -1;
    }
    /* New-style anding: "0 byte&0x80 =0x80 dynamically linked" */
    if (*l == '&') {
        ++l;
        m->mask = signextend(serv, m, strtol(l, &l, 0));
    }
    else
        m->mask = ~0L;
    EATAB;

    switch (*l) {
    case '>':
    case '<':
        /* Old-style anding: "0 byte &0x80 dynamically linked" */
    case '&':
    case '^':
    case '=':
        m->reln = *l;
        ++l;
        break;
    case '!':
        if (m->type != STRING) {
            m->reln = *l;
            ++l;
            break;
        }
        /* FALL THROUGH */
    default:
        if (*l == 'x' && apr_isspace(l[1])) {
            m->reln = *l;
            ++l;
            goto GetDesc;  /* Bill The Cat */
        }
        m->reln = '=';
        break;
    }
    EATAB;

    if (getvalue(serv, m, &l))
        return -1;
    /*
     * 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;
    strncpy(m->desc, l, sizeof(m->desc) - 1);
    m->desc[sizeof(m->desc) - 1] = '\0';

#if MIME_MAGIC_DEBUG
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, serv,
                MODNAME ": parse line=%d m=%x next=%x cont=%d desc=%s",
                lineno, m, m->next, m->cont_level, m->desc);
#endif /* MIME_MAGIC_DEBUG */

    return 0;
}

/*
 * 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.
 */
static int getvalue(server_rec *s, struct magic *m, char **p)
{
    int slen;

    if (m->type == STRING) {
        *p = getstr(s, *p, m->value.s, sizeof(m->value.s), &slen);
        m->vallen = slen;
    }
    else if (m->reln != 'x')
        m->value.l = signextend(s, m, strtol(*p, p, 0));
    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.
 */
static char *getstr(server_rec *serv, register char *s, register char *p,
                    int plen, int *slen)
{
    char *origs = s, *origp = p;
    char *pmax = p + plen - 1;
    register int c;
    register int val;

    while ((c = *s++) != '\0') {
        if (apr_isspace(c))
            break;
        if (p >= pmax) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": string too long: %s", origs);
            break;
        }
        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 3 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;
                        c = hextoint(*s++);
                        if (c >= 0) {
                            val = (val << 4) + c;
                        }
                        else
                            --s;
                    }
                    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. */
static int hextoint(int c)
{
    if (apr_isdigit(c))
        return c - '0';
    if ((c >= 'a') && (c <= 'f'))
        return c + 10 - 'a';
    if ((c >= 'A') && (c <= 'F'))
        return c + 10 - 'A';
    return -1;
}


/*
 * return DONE to indicate it's been handled
 * return OK to indicate it's a regular file still needing handling
 * other returns indicate a failure of some sort
 */
static int fsmagic(request_rec *r, const char *fn)
{
    switch (r->finfo.filetype) {
    case APR_DIR:
        magic_rsl_puts(r, DIR_MAGIC_TYPE);
        return DONE;
    case APR_CHR:
        /*
         * (void) magic_rsl_printf(r,"character special (%d/%d)",
         * major(sb->st_rdev), minor(sb->st_rdev));
         */
        (void) magic_rsl_puts(r, MIME_BINARY_UNKNOWN);
        return DONE;
    case APR_BLK:
        /*
         * (void) magic_rsl_printf(r,"block special (%d/%d)",
         * major(sb->st_rdev), minor(sb->st_rdev));
         */
        (void) magic_rsl_puts(r, MIME_BINARY_UNKNOWN);
        return DONE;
        /* TODO add code to handle V7 MUX and Blit MUX files */
    case APR_PIPE:
        /*
         * magic_rsl_puts(r,"fifo (named pipe)");
         */
        (void) magic_rsl_puts(r, MIME_BINARY_UNKNOWN);
        return DONE;
    case APR_LNK:
        /* We used stat(), the only possible reason for this is that the
         * symlink is broken.
         */
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                    MODNAME ": broken symlink (%s)", fn);
        return HTTP_INTERNAL_SERVER_ERROR;
    case APR_SOCK:
        magic_rsl_puts(r, MIME_BINARY_UNKNOWN);
        return DONE;
    case APR_REG:
        break;
    default:
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      MODNAME ": invalid file type %d.", r->finfo.filetype);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /*
     * regular file, check next possibility
     */
    if (r->finfo.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, apr_size_t 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, apr_size_t 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_DEBUG, 0, 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 (apr_isprint((((unsigned long) m) >> 24) & 255) &&
            apr_isprint((((unsigned long) m) >> 16) & 255) &&
            apr_isprint((((unsigned long) m) >> 8) & 255) &&
            apr_isprint(((unsigned long) m) & 255)) {
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, 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_DEBUG, 0, 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_DEBUG, 0, 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_DEBUG, 0, 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_DEBUG, 0, 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_DEBUG, 0, r,
                    MODNAME ": matched after %d rules", rule_counter);
#endif
        return 1;  /* all through */
    }
#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, 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;
    unsigned long v;
    char time_str[APR_CTIME_LEN];

    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:
        apr_ctime(time_str, apr_time_from_sec(*(time_t *)&p->l));
        pp = time_str;
        (void) magic_rsl_printf(r, m->desc, pp);
        return;
    default:
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, 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_ERR, 0, 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, apr_size_t 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_ERR, 0, 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_ERR, 0, 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_DEBUG, 0, r,
                    "%lu == *any* = 1", v);
#endif
        matched = 1;
        break;

    case '!':
        matched = v != l;
#if MIME_MAGIC_DEBUG
        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                    "%lu != %lu = %d", v, l, matched);
#endif
        break;

    case '=':
        matched = v == l;
#if MIME_MAGIC_DEBUG
        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, 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_DEBUG, 0, r,
                        "%lu > %lu = %d", v, l, matched);
#endif
        }
        else {
            matched = (long) v > (long) l;
#if MIME_MAGIC_DEBUG
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, 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_DEBUG, 0, r,
                        "%lu < %lu = %d", v, l, matched);
#endif
        }
        else {
            matched = (long) v < (long) l;
#if MIME_MAGIC_DEBUG
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                        "%ld < %ld = %d", v, l, matched);
#endif
        }
        break;

    case '&':
        matched = (v & l) == l;
#if MIME_MAGIC_DEBUG
        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, 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_DEBUG, 0, r,
                    "((%lx & %lx) != %lx) = %d", v, l, l, matched);
#endif
        break;

    default:
        /* bogosity, pretend it didn't match */
        matched = 0;
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                    MODNAME ": mcheck: can't happen: invalid relation %d.",
                    m->reln);
        break;
    }

    return matched;
}

/* an optimization over plain strcmp() */
#define    STREQ(a, b)    (*(a) == *(b) && strcmp((a), (b)) == 0)

static int ascmagic(request_rec *r, unsigned char *buf, apr_size_t nbytes)
{
    int has_escapes = 0;
    unsigned char *s;
    char nbuf[HOWMANY + 1];  /* one extra for terminating '\0' */
    char *token;
    register struct names *p;
    int small_nbytes;
    char *strtok_state;

    /* these are easy, do them first */

    /*
     * for troff, look for . + letter + letter or .\"; this must be done to
     * disambiguate tar archives' ./file and other trash from real troff
     * input.
     */
    if (*buf == '.') {
        unsigned char *tp = buf + 1;

        while (apr_isspace(*tp))
            ++tp;  /* skip leading whitespace */
        if ((apr_isalnum(*tp) || *tp == '\\') &&
             (apr_isalnum(*(tp + 1)) || *tp == '"')) {
            magic_rsl_puts(r, "application/x-troff");
            return 1;
        }
    }
    if ((*buf == 'c' || *buf == 'C') && apr_isspace(*(buf + 1))) {
        /* Fortran */
        magic_rsl_puts(r, "text/plain");
        return 1;
    }

    /* look for tokens from names.h - this is expensive!, so we'll limit
     * ourselves to only SMALL_HOWMANY bytes */
    small_nbytes = (nbytes > SMALL_HOWMANY) ? SMALL_HOWMANY : nbytes;
    /* make a copy of the buffer here because apr_strtok() will destroy it */
    s = (unsigned char *) memcpy(nbuf, buf, small_nbytes);
    s[small_nbytes] = '\0';
    has_escapes = (memchr(s, '\033', small_nbytes) != NULL);
    while ((token = apr_strtok((char *) s, " \t\n\r\f", &strtok_state)) != NULL) {
        s = NULL;  /* make apr_strtok() keep on tokin' */
        for (p = names; p < names + NNAMES; p++) {
            if (STREQ(p->name, token)) {
                magic_rsl_puts(r, types[p->type]);
                if (has_escapes)
                    magic_rsl_puts(r, " (with escape sequences)");
                return 1;
            }
        }
    }

    switch (is_tar(buf, nbytes)) {
    case 1:
        /* V7 tar archive */
        magic_rsl_puts(r, "application/x-tar");
        return 1;
    case 2:
        /* POSIX tar archive */
        magic_rsl_puts(r, "application/x-tar");
        return 1;
    }

    /* all else fails, but it is ascii... */
    return 0;
}


/*
 * compress routines: zmagic() - returns 0 if not recognized, uncompresses
 * and prints information if recognized uncompress(s, method, old, n, newch)
 * - uncompress old into new, using method, return sizeof new
 */

static struct {
    char *magic;
    apr_size_t maglen;
    char *argv[3];
    int silent;
    char *encoding;  /* MUST be lowercase */
} compr[] = {

    /* we use gzip here rather than uncompress because we have to pass
     * it a full filename -- and uncompress only considers filenames
     * ending with .Z
     */
    {
        "\037\235", 2, {
            "gzip", "-dcq", NULL
        }, 0, "x-compress"
    },
    {
        "\037\213", 2, {
            "gzip", "-dcq", NULL
        }, 1, "x-gzip"
    },
    /*
     * XXX pcat does not work, cause I don't know how to make it read stdin,
     * so we use gzip
     */
    {
        "\037\036", 2, {
            "gzip", "-dcq", NULL
        }, 0, "x-gzip"
    },
};

static int ncompr = sizeof(compr) / sizeof(compr[0]);

static int zmagic(request_rec *r, unsigned char *buf, apr_size_t nbytes)
{
    unsigned char *newbuf;
    int newsize;
    int i;

    for (i = 0; i < ncompr; i++) {
        if (nbytes < compr[i].maglen)
            continue;
        if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0)
            break;
    }

    if (i == ncompr)
        return 0;

    if ((newsize = uncompress(r, i, &newbuf, nbytes)) > 0) {
        if (tryit(r, newbuf, newsize, 0) != OK) {
            return 0;
        }

        /* set encoding type in the request record */
        r->content_encoding = compr[i].encoding;
    }
    return 1;
}


struct uncompress_parms {
    request_rec *r;
    int method;
};

static int create_uncompress_child(struct uncompress_parms *parm, apr_pool_t *cntxt,
                                   apr_file_t **pipe_in)
{
    int rc = 1;
    const char *new_argv[4];
    const char *const *env;
    request_rec *r = parm->r;
    apr_pool_t *child_context = cntxt;
    apr_procattr_t *procattr;
    apr_proc_t *procnew;

    /* XXX missing 1.3 logic:
     *
     * what happens when !compr[parm->method].silent?
     * Should we create the err pipe, read it, and copy to the log?
     */

    env = (const char *const *)ap_create_environment(child_context, r->subprocess_env);

    if ((apr_procattr_create(&procattr, child_context) != APR_SUCCESS) ||
        (apr_procattr_io_set(procattr, APR_FULL_BLOCK,
                           APR_FULL_BLOCK, APR_NO_PIPE)   != APR_SUCCESS) ||
        (apr_procattr_dir_set(procattr, r->filename)        != APR_SUCCESS) ||
        (apr_procattr_cmdtype_set(procattr, APR_PROGRAM)    != APR_SUCCESS)) {
        /* Something bad happened, tell the world. */
        ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_ENOPROC, r,
               "couldn't setup child process: %s", r->filename);
    }
    else {
        new_argv[0] = compr[parm->method].argv[0];
        new_argv[1] = compr[parm->method].argv[1];
        new_argv[2] = r->filename;
        new_argv[3] = NULL;

        procnew = apr_pcalloc(child_context, sizeof(*procnew));
        rc = apr_proc_create(procnew, compr[parm->method].argv[0],
                               new_argv, env, procattr, child_context);

        if (rc != APR_SUCCESS) {
            /* Bad things happened. Everyone should have cleaned up. */
            ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_ENOPROC, r,
                          MODNAME ": could not execute `%s'.",
                          compr[parm->method].argv[0]);
        }
        else {
            apr_pool_note_subprocess(child_context, procnew, APR_KILL_AFTER_TIMEOUT);
            *pipe_in = procnew->out;
        }
    }

    return (rc);
}

static int uncompress(request_rec *r, int method,
                      unsigned char **newch, apr_size_t n)
{
    struct uncompress_parms parm;
    apr_file_t *pipe_out = NULL;
    apr_pool_t *sub_context;
    apr_status_t rv;

    parm.r = r;
    parm.method = method;

    /* We make a sub_pool so that we can collect our child early, otherwise
     * there are cases (i.e. generating directory indicies with mod_autoindex)
     * where we would end up with LOTS of zombies.
     */
    if (apr_pool_create(&sub_context, r->pool) != APR_SUCCESS)
        return -1;

    if ((rv = create_uncompress_child(&parm, sub_context, &pipe_out)) != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                    MODNAME ": couldn't spawn uncompress process: %s", r->uri);
        return -1;
    }

    *newch = (unsigned char *) apr_palloc(r->pool, n);
    rv = apr_file_read(pipe_out, *newch, &n);
    if (n == 0) {
        apr_pool_destroy(sub_context);
        ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
            MODNAME ": read failed from uncompress of %s", r->filename);
        return -1;
    }
    apr_pool_destroy(sub_context);
    return n;
}

/*
 * is_tar() -- figure out whether file is a tar archive.
 *
 * Stolen (by author of file utility) from the public domain tar program: Public
 * Domain version written 26 Aug 1985 John Gilmore (ihnp4!hoptoad!gnu).
 *
 * @(#)list.c 1.18 9/23/86 Public Domain - gnu $Id: mod_mime_magic.c,v 1.7
 * 1997/06/24 00:41:02 ikluft Exp ikluft $
 *
 * Comments changed and some code/comments reformatted for file command by Ian
 * Darwin.
 */

#define isodigit(c) (((unsigned char)(c) >= '0') && ((unsigned char)(c) <= '7'))

/*
 * Return 0 if the checksum is bad (i.e., probably not a tar archive), 1 for
 * old UNIX tar file, 2 for Unix Std (POSIX) tar file.
 */

static int is_tar(unsigned char *buf, apr_size_t nbytes)
{
    register union record *header = (union record *) buf;
    register int i;
    register long sum, recsum;
    register char *p;

    if (nbytes < sizeof(union record))
               return 0;

    recsum = from_oct(8, header->header.chksum);

    sum = 0;
    p = header->charptr;
    for (i = sizeof(union record); --i >= 0;) {
        /*
         * We can't use unsigned char here because of old compilers, e.g. V7.
         */
        sum += 0xFF & *p++;
    }

    /* Adjust checksum to count the "chksum" field as blanks. */
    for (i = sizeof(header->header.chksum); --i >= 0;)
        sum -= 0xFF & header->header.chksum[i];
    sum += ' ' * sizeof header->header.chksum;

    if (sum != recsum)
        return 0;   /* Not a tar archive */

    if (0 == strcmp(header->header.magic, TMAGIC))
        return 2;   /* Unix Standard tar archive */

    return 1;       /* Old fashioned tar archive */
}


/*
 * Quick and dirty octal conversion.
 *
 * Result is -1 if the field is invalid (all blank, or nonoctal).
 */
static long from_oct(int digs, char *where)
{
    register long value;

    while (apr_isspace(*where)) {  /* Skip spaces */
        where++;
        if (--digs <= 0)
            return -1;  /* All blank field */
    }
    value = 0;
    while (digs > 0 && isodigit(*where)) {  /* Scan til nonoctal */
        value = (value << 3) | (*where++ - '0');
        --digs;
    }

    if (digs > 0 && *where && !apr_isspace(*where))
        return -1;  /* Ended on non-space/nul */

    return value;
}

/*
 * Check for file-revision suffix
 *
 * This is for an obscure document control system used on an intranet.
 * The web representation of each file's revision has an @1, @2, etc
 * appended with the revision number.  This needs to be stripped off to
 * find the file suffix, which can be recognized by sending the name back
 * through a sub-request.  The base file name (without the @num suffix)
 * must exist because its type will be used as the result.
 */
static int revision_suffix(request_rec *r)
{
    int suffix_pos, result;
    char *sub_filename;
    request_rec *sub;

#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                MODNAME ": revision_suffix checking %s", r->filename);
#endif /* MIME_MAGIC_DEBUG */

    /* check for recognized revision suffix */
    suffix_pos = strlen(r->filename) - 1;
    if (!apr_isdigit(r->filename[suffix_pos])) {
        return 0;
    }
    while (suffix_pos >= 0 && apr_isdigit(r->filename[suffix_pos]))
        suffix_pos--;
    if (suffix_pos < 0 || r->filename[suffix_pos] != '@') {
        return 0;
    }

    /* perform sub-request for the file name without the suffix */
    result = 0;
    sub_filename = apr_pstrndup(r->pool, r->filename, suffix_pos);
#if MIME_MAGIC_DEBUG
    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                MODNAME ": subrequest lookup for %s", sub_filename);
#endif /* MIME_MAGIC_DEBUG */
    sub = ap_sub_req_lookup_file(sub_filename, r, NULL);

    /* extract content type/encoding/language from sub-request */
    if (sub->content_type) {
        ap_set_content_type(r, apr_pstrdup(r->pool, sub->content_type));
#if MIME_MAGIC_DEBUG
        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                    MODNAME ": subrequest %s got %s",
                    sub_filename, r->content_type);
#endif /* MIME_MAGIC_DEBUG */
        if (sub->content_encoding)
            r->content_encoding =
                apr_pstrdup(r->pool, sub->content_encoding);
        if (sub->content_languages) {
            int n;
            r->content_languages = apr_array_copy(r->pool,
                                                  sub->content_languages);
            for (n = 0; n < r->content_languages->nelts; ++n) {
                char **lang = ((char **)r->content_languages->elts) + n;
                *lang = apr_pstrdup(r->pool, *lang);
            }
        }
        result = 1;
    }

    /* clean up */
    ap_destroy_sub_req(sub);

    return result;
}

/*
 * initialize the module
 */
static int magic_init(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *main_server)
{
    int result;
    magic_server_config_rec *conf;
    magic_server_config_rec *main_conf;
    server_rec *s;
#if MIME_MAGIC_DEBUG
    struct magic *m, *prevm;
#endif /* MIME_MAGIC_DEBUG */

    main_conf = ap_get_module_config(main_server->module_config, &mime_magic_module);
    for (s = main_server; s; s = s->next) {
        conf = ap_get_module_config(s->module_config, &mime_magic_module);
        if (conf->magicfile == NULL && s != main_server) {
            /* inherits from the parent */
            *conf = *main_conf;
        }
        else if (conf->magicfile) {
            result = apprentice(s, p);
            if (result == -1)
                return OK;
#if MIME_MAGIC_DEBUG
            prevm = 0;
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                        MODNAME ": magic_init 1 test");
            for (m = conf->magic; m; m = m->next) {
                if (apr_isprint((((unsigned long) m) >> 24) & 255) &&
                    apr_isprint((((unsigned long) m) >> 16) & 255) &&
                    apr_isprint((((unsigned long) m) >> 8) & 255) &&
                    apr_isprint(((unsigned long) m) & 255)) {
                    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                                MODNAME ": magic_init 1: POINTER CLOBBERED! "
                                "m=\"%c%c%c%c\" line=%d",
                                (((unsigned long) m) >> 24) & 255,
                                (((unsigned long) m) >> 16) & 255,
                                (((unsigned long) m) >> 8) & 255,
                                ((unsigned long) m) & 255,
                                prevm ? prevm->lineno : -1);
                    break;
                }
                prevm = m;
            }
#endif
        }
    }
    return OK;
}

/*
 * Find the Content-Type from any resource this module has available
 */

static int magic_find_ct(request_rec *r)
{
    int result;
    magic_server_config_rec *conf;

    /* the file has to exist */
    if (r->finfo.filetype == 0 || !r->filename) {
        return DECLINED;
    }

    /* was someone else already here? */
    if (r->content_type) {
        return DECLINED;
    }

    conf = ap_get_module_config(r->server->module_config, &mime_magic_module);
    if (!conf || !conf->magic) {
        return DECLINED;
    }

    /* initialize per-request info */
    if (!magic_set_config(r)) {
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* try excluding file-revision suffixes */
    if (revision_suffix(r) != 1) {
        /* process it based on the file contents */
        if ((result = magic_process(r)) != OK) {
            return result;
        }
    }

    /* if we have any results, put them in the request structure */
    return magic_rsl_to_request(r);
}

static void register_hooks(apr_pool_t *p)
{
    static const char * const aszPre[]={ "mod_mime.c", NULL };

    /* mod_mime_magic should be run after mod_mime, if at all. */

    ap_hook_type_checker(magic_find_ct, aszPre, NULL, APR_HOOK_MIDDLE);
    ap_hook_post_config(magic_init, NULL, NULL, APR_HOOK_FIRST);
}

/*
 * Apache API module interface
 */

module AP_MODULE_DECLARE_DATA mime_magic_module =
{
    STANDARD20_MODULE_STUFF,
    NULL,                      /* dir config creator */
    NULL,                      /* dir merger --- default is to override */
    create_magic_server_config,        /* server config */
    merge_magic_server_config, /* merge server config */
    mime_magic_cmds,           /* command apr_table_t */
    register_hooks              /* register hooks */
};



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