mod_rewrite.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.
 */

/*                       _                            _ _
 *   _ __ ___   ___   __| |    _ __ _____      ___ __(_) |_ ___
 *  | '_ ` _ \ / _ \ / _` |   | '__/ _ \ \ /\ / / '__| | __/ _ \
 *  | | | | | | (_) | (_| |   | | |  __/\ V  V /| |  | | ||  __/
 *  |_| |_| |_|\___/ \__,_|___|_|  \___| \_/\_/ |_|  |_|\__\___|
 *                       |_____|
 *
 *  URL Rewriting Module
 *
 *  This module uses a rule-based rewriting engine (based on a
 *  regular-expression parser) to rewrite requested URLs on the fly.
 *
 *  It supports an unlimited number of additional rule conditions (which can
 *  operate on a lot of variables, even on HTTP headers) for granular
 *  matching and even external database lookups (either via plain text
 *  tables, DBM hash files or even external processes) for advanced URL
 *  substitution.
 *
 *  It operates on the full URLs (including the PATH_INFO part) both in
 *  per-server context (httpd.conf) and per-dir context (.htaccess) and even
 *  can generate QUERY_STRING parts on result.   The rewriting result finally
 *  can lead to internal subprocessing, external request redirection or even
 *  to internal proxy throughput.
 *
 *  This module was originally written in April 1996 and
 *  gifted exclusively to the The Apache Software Foundation in July 1997 by
 *
 *      Ralf S. Engelschall
 *      rse engelschall.com
 *      www.engelschall.com
 */

#include "apr.h"
#include "apr_strings.h"
#include "apr_hash.h"
#include "apr_user.h"
#include "apr_lib.h"
#include "apr_signal.h"
#include "apr_global_mutex.h"
#include "apr_dbm.h"

#if APR_HAS_THREADS
#include "apr_thread_mutex.h"
#endif

#define APR_WANT_MEMFUNC
#define APR_WANT_STRFUNC
#define APR_WANT_IOVEC
#include "apr_want.h"

/* XXX: Do we really need these headers? */
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#if APR_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if APR_HAVE_STDARG_H
#include <stdarg.h>
#endif
#if APR_HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if APR_HAVE_CTYPE_H
#include <ctype.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 "http_vhost.h"

#include "mod_ssl.h"

#include "mod_rewrite.h"

#ifdef AP_NEED_SET_MUTEX_PERMS
#include "unixd.h"
#endif

/*
 * in order to improve performance on running production systems, you
 * may strip all rewritelog code entirely from mod_rewrite by using the
 * -DREWRITELOG_DISABLED compiler option.
 *
 * DO NOT USE THIS OPTION FOR PUBLIC BINARY RELEASES. Otherwise YOU are
 * responsible for answering all the mod_rewrite questions out there.
 */
#ifndef REWRITELOG_DISABLED

#define rewritelog(x) do_rewritelog x
#define REWRITELOG_MODE  ( APR_UREAD | APR_UWRITE | APR_GREAD | APR_WREAD )
#define REWRITELOG_FLAGS ( APR_WRITE | APR_APPEND | APR_CREATE )

#else /* !REWRITELOG_DISABLED */

#define rewritelog(x)

#endif /* REWRITELOG_DISABLED */

/* remembered mime-type for [T=...] */
#define REWRITE_FORCED_MIMETYPE_NOTEVAR "rewrite-forced-mimetype"
#define REWRITE_FORCED_HANDLER_NOTEVAR  "rewrite-forced-handler"

#define ENVVAR_SCRIPT_URL "SCRIPT_URL"
#define REDIRECT_ENVVAR_SCRIPT_URL "REDIRECT_" ENVVAR_SCRIPT_URL
#define ENVVAR_SCRIPT_URI "SCRIPT_URI"

#define CONDFLAG_NONE               1<<0
#define CONDFLAG_NOCASE             1<<1
#define CONDFLAG_NOTMATCH           1<<2
#define CONDFLAG_ORNEXT             1<<3
#define CONDFLAG_NOVARY             1<<4

#define RULEFLAG_NONE               1<<0
#define RULEFLAG_FORCEREDIRECT      1<<1
#define RULEFLAG_LASTRULE           1<<2
#define RULEFLAG_NEWROUND           1<<3
#define RULEFLAG_CHAIN              1<<4
#define RULEFLAG_IGNOREONSUBREQ     1<<5
#define RULEFLAG_NOTMATCH           1<<6
#define RULEFLAG_PROXY              1<<7
#define RULEFLAG_PASSTHROUGH        1<<8
#define RULEFLAG_QSAPPEND           1<<9
#define RULEFLAG_NOCASE             1<<10
#define RULEFLAG_NOESCAPE           1<<11
#define RULEFLAG_NOSUB              1<<12
#define RULEFLAG_STATUS             1<<13
#define RULEFLAG_ESCAPEBACKREF      1<<14

/* return code of the rewrite rule
 * the result may be escaped - or not
 */
#define ACTION_NORMAL               1<<0
#define ACTION_NOESCAPE             1<<1
#define ACTION_STATUS               1<<2


#define MAPTYPE_TXT                 1<<0
#define MAPTYPE_DBM                 1<<1
#define MAPTYPE_PRG                 1<<2
#define MAPTYPE_INT                 1<<3
#define MAPTYPE_RND                 1<<4

#define ENGINE_DISABLED             1<<0
#define ENGINE_ENABLED              1<<1

#define OPTION_NONE                 1<<0
#define OPTION_INHERIT              1<<1

#ifndef RAND_MAX
#define RAND_MAX 32767
#endif

/* max cookie size in rfc 2109 */
/* XXX: not used at all. We should do a check somewhere and/or cut the cookie */
#define MAX_COOKIE_LEN 4096

/* max line length (incl.\n) in text rewrite maps */
#ifndef REWRITE_MAX_TXT_MAP_LINE
#define REWRITE_MAX_TXT_MAP_LINE 1024
#endif

/* buffer length for prg rewrite maps */
#ifndef REWRITE_PRG_MAP_BUF
#define REWRITE_PRG_MAP_BUF 1024
#endif

/* for better readbility */
#define LEFT_CURLY  '{'
#define RIGHT_CURLY '}'

/*
 * expansion result items on the stack to save some cycles
 *
 * (5 == about 2 variables like "foo%{var}bar%{var}baz")
 */
#define SMALL_EXPANSION 5

/*
 * check that a subrequest won't cause infinite recursion
 *
 * either not in a subrequest, or in a subrequest
 * and URIs aren't NULL and sub/main URIs differ
 */
#define subreq_ok(r) (!r->main || \
    (r->main->uri && r->uri && strcmp(r->main->uri, r->uri)))


/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                 Types and Structures
 * |                                                       |
 * +-------------------------------------------------------+
 */

typedef struct {
    const char *datafile;          /* filename for map data files         */
    const char *dbmtype;           /* dbm type for dbm map data files     */
    const char *checkfile;         /* filename to check for map existence */
    const char *cachename;         /* for cached maps (txt/rnd/dbm)       */
    int   type;                    /* the type of the map                 */
    apr_file_t *fpin;              /* in  file pointer for program maps   */
    apr_file_t *fpout;             /* out file pointer for program maps   */
    apr_file_t *fperr;             /* err file pointer for program maps   */
    char *(*func)(request_rec *,   /* function pointer for internal maps  */
                  char *);
    char **argv;                   /* argv of the external rewrite map    */
    const char *checkfile2;        /* filename to check for map existence
                                      NULL if only one file               */
} rewritemap_entry;

/* special pattern types for RewriteCond */
typedef enum {
    CONDPAT_REGEX = 0,
    CONDPAT_FILE_EXISTS,
    CONDPAT_FILE_SIZE,
    CONDPAT_FILE_LINK,
    CONDPAT_FILE_DIR,
    CONDPAT_FILE_XBIT,
    CONDPAT_LU_URL,
    CONDPAT_LU_FILE,
    CONDPAT_STR_GT,
    CONDPAT_STR_LT,
    CONDPAT_STR_EQ
} pattern_type;

typedef struct {
    char        *input;   /* Input string of RewriteCond   */
    char        *pattern; /* the RegExp pattern string     */
    ap_regex_t  *regexp;  /* the precompiled regexp        */
    int          flags;   /* Flags which control the match */
    pattern_type ptype;   /* pattern type                  */
} rewritecond_entry;

/* single linked list for env vars and cookies */
typedef struct data_item {
    struct data_item *next;
    char *data;
} data_item;

typedef struct {
    apr_array_header_t *rewriteconds;/* the corresponding RewriteCond entries */
    char      *pattern;              /* the RegExp pattern string             */
    ap_regex_t *regexp;              /* the RegExp pattern compilation        */
    char      *output;               /* the Substitution string               */
    int        flags;                /* Flags which control the substitution  */
    char      *forced_mimetype;      /* forced MIME type of substitution      */
    char      *forced_handler;       /* forced content handler of subst.      */
    int        forced_responsecode;  /* forced HTTP response status           */
    data_item *env;                  /* added environment variables           */
    data_item *cookie;               /* added cookies                         */
    int        skip;                 /* number of next rules to skip          */
} rewriterule_entry;

typedef struct {
    int           state;              /* the RewriteEngine state            */
    int           options;            /* the RewriteOption state            */
#ifndef REWRITELOG_DISABLED
    const char   *rewritelogfile;     /* the RewriteLog filename            */
    apr_file_t   *rewritelogfp;       /* the RewriteLog open filepointer    */
    int           rewriteloglevel;    /* the RewriteLog level of verbosity  */
#endif
    apr_hash_t         *rewritemaps;  /* the RewriteMap entries             */
    apr_array_header_t *rewriteconds; /* the RewriteCond entries (temp.)    */
    apr_array_header_t *rewriterules; /* the RewriteRule entries            */
    server_rec   *server;             /* the corresponding server indicator */
} rewrite_server_conf;

typedef struct {
    int           state;              /* the RewriteEngine state           */
    int           options;            /* the RewriteOption state           */
    apr_array_header_t *rewriteconds; /* the RewriteCond entries (temp.)   */
    apr_array_header_t *rewriterules; /* the RewriteRule entries           */
    char         *directory;          /* the directory where it applies    */
    const char   *baseurl;            /* the base-URL  where it applies    */
} rewrite_perdir_conf;

/* the (per-child) cache structures.
 */
typedef struct cache {
    apr_pool_t         *pool;
    apr_hash_t         *maps;
#if APR_HAS_THREADS
    apr_thread_mutex_t *lock;
#endif
} cache;

/* cached maps contain an mtime for the whole map and live in a subpool
 * of the cachep->pool. That makes it easy to forget them if necessary.
 */
typedef struct {
    apr_time_t mtime;
    apr_pool_t *pool;
    apr_hash_t *entries;
} cachedmap;

/* the regex structure for the
 * substitution of backreferences
 */
typedef struct backrefinfo {
    char *source;
    int nsub;
    ap_regmatch_t regmatch[AP_MAX_REG_MATCH];
} backrefinfo;

/* single linked list used for
 * variable expansion
 */
typedef struct result_list {
    struct result_list *next;
    apr_size_t len;
    const char *string;
} result_list;

/* context structure for variable lookup and expansion
 */
typedef struct {
    request_rec *r;
    const char  *uri;
    const char  *vary_this;
    const char  *vary;
    char        *perdir;
    backrefinfo briRR;
    backrefinfo briRC;
} rewrite_ctx;

/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                 static module data
 * |                                                       |
 * +-------------------------------------------------------+
 */

/* the global module structure */
module AP_MODULE_DECLARE_DATA rewrite_module;

/* rewritemap int: handler function registry */
static apr_hash_t *mapfunc_hash;

/* the cache */
static cache *cachep;

/* whether proxy module is available or not */
static int proxy_available;

/* whether random seed can be reaped */
static int rewrite_rand_init_done = 0;

/* Locks/Mutexes */
static const char *lockname;
static apr_global_mutex_t *rewrite_mapr_lock_acquire = NULL;

#ifndef REWRITELOG_DISABLED
static apr_global_mutex_t *rewrite_log_lock = NULL;
#endif

/* Optional functions imported from mod_ssl when loaded: */
static APR_OPTIONAL_FN_TYPE(ssl_var_lookup) *rewrite_ssl_lookup = NULL;
static APR_OPTIONAL_FN_TYPE(ssl_is_https) *rewrite_is_https = NULL;

/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |              rewriting logfile support
 * |                                                       |
 * +-------------------------------------------------------+
 */

#ifndef REWRITELOG_DISABLED
static char *current_logtime(request_rec *r)
{
    apr_time_exp_t t;
    char tstr[80];
    apr_size_t len;

    apr_time_exp_lt(&t, apr_time_now());

    apr_strftime(tstr, &len, sizeof(tstr), "[%d/%b/%Y:%H:%M:%S ", &t);
    apr_snprintf(tstr+len, sizeof(tstr)-len, "%c%.2d%.2d]",
                 t.tm_gmtoff < 0 ? '-' : '+',
                 t.tm_gmtoff / (60*60), t.tm_gmtoff % (60*60));

    return apr_pstrdup(r->pool, tstr);
}

static int open_rewritelog(server_rec *s, apr_pool_t *p)
{
    rewrite_server_conf *conf;
    const char *fname;

    conf = ap_get_module_config(s->module_config, &rewrite_module);

    /* - no logfile configured
     * - logfilename empty
     * - virtual log shared w/ main server
     */
    if (!conf->rewritelogfile || !*conf->rewritelogfile || conf->rewritelogfp) {
        return 1;
    }

    if (*conf->rewritelogfile == '|') {
        piped_log *pl;

        fname = ap_server_root_relative(p, conf->rewritelogfile+1);
        if (!fname) {
            ap_log_error(APLOG_MARK, APLOG_ERR, APR_EBADPATH, s,
                         "mod_rewrite: Invalid RewriteLog "
                         "path %s", conf->rewritelogfile+1);
            return 0;
        }

        if ((pl = ap_open_piped_log(p, fname)) == NULL) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
                         "mod_rewrite: could not open reliable pipe "
                         "to RewriteLog filter %s", fname);