mod_mime_magic.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

/* 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 <[e-mail]>
 * 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 */