http_core.h

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed 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.
 */

#ifndef APACHE_HTTP_CORE_H
#define APACHE_HTTP_CORE_H

#include "apr.h"
#include "apr_hash.h"
#include "apr_optional.h"
#include "util_filter.h"

#if APR_HAVE_STRUCT_RLIMIT
#include <sys/time.h>
#include <sys/resource.h>
#endif


#ifdef __cplusplus
extern "C" {
#endif

/**
 * @package CORE HTTP Daemon
 */

/* ****************************************************************
 *
 * The most basic server code is encapsulated in a single module
 * known as the core, which is just *barely* functional enough to
 * serve documents, though not terribly well.
 *
 * Largely for NCSA back-compatibility reasons, the core needs to
 * make pieces of its config structures available to other modules.
 * The accessors are declared here, along with the interpretation
 * of one of them (allow_options).
 */

#define OPT_NONE 0
#define OPT_INDEXES 1
#define OPT_INCLUDES 2
#define OPT_SYM_LINKS 4
#define OPT_EXECCGI 8
#define OPT_UNSET 16
#define OPT_INCNOEXEC 32
#define OPT_SYM_OWNER 64
#define OPT_MULTI 128
#define OPT_ALL (OPT_INDEXES|OPT_INCLUDES|OPT_SYM_LINKS|OPT_EXECCGI)

/* options for get_remote_host() */
/* REMOTE_HOST returns the hostname, or NULL if the hostname
 * lookup fails.  It will force a DNS lookup according to the
 * HostnameLookups setting.
 */
#define REMOTE_HOST (0)

/* REMOTE_NAME returns the hostname, or the dotted quad if the
 * hostname lookup fails.  It will force a DNS lookup according
 * to the HostnameLookups setting.
 */
#define REMOTE_NAME (1)

/* REMOTE_NOLOOKUP is like REMOTE_NAME except that a DNS lookup is
 * never forced.
 */
#define REMOTE_NOLOOKUP (2)

/* REMOTE_DOUBLE_REV will always force a DNS lookup, and also force
 * a double reverse lookup, regardless of the HostnameLookups
 * setting.  The result is the (double reverse checked) hostname,
 * or NULL if any of the lookups fail.
 */
#define REMOTE_DOUBLE_REV (3)

#define SATISFY_ALL 0
#define SATISFY_ANY 1
#define SATISFY_NOSPEC 2

/* Make sure we don't write less than 8000 bytes at any one time.
 */
#define AP_MIN_BYTES_TO_WRITE  8000

/* default maximum of internal redirects */
# define AP_DEFAULT_MAX_INTERNAL_REDIRECTS 10

/* default maximum subrequest nesting level */
# define AP_DEFAULT_MAX_SUBREQ_DEPTH 10

/**
 * Retrieve the value of Options for this request
 * @param r The current request
 * @return the Options bitmask
 * @deffunc int ap_allow_options(request_rec *r)
 */
AP_DECLARE(int) ap_allow_options(request_rec *r);

/**
 * Retrieve the value of the AllowOverride for this request
 * @param r The current request
 * @return the overrides bitmask
 * @deffunc int ap_allow_overrides(request_rec *r)
 */
AP_DECLARE(int) ap_allow_overrides(request_rec *r);

/**
 * Retrieve the value of the DefaultType directive, or text/plain if not set
 * @param r The current request
 * @return The default type
 * @deffunc const char *ap_default_type(request_rec *r)
 */
AP_DECLARE(const char *) ap_default_type(request_rec *r);     

/**
 * Retrieve the document root for this server
 * @param r The current request
 * @warning Don't use this!  If your request went through a Userdir, or 
 * something like that, it'll screw you.  But it's back-compatible...
 * @return The document root
 * @deffunc const char *ap_document_root(request_rec *r)
 */
AP_DECLARE(const char *) ap_document_root(request_rec *r);

/**
 * Lookup the remote client's DNS name or IP address
 * @param conn The current connection
 * @param dir_config The directory config vector from the request
 * @param type The type of lookup to perform.  One of:
 * <pre>
 *     REMOTE_HOST returns the hostname, or NULL if the hostname
 *                 lookup fails.  It will force a DNS lookup according to the
 *                 HostnameLookups setting.
 *     REMOTE_NAME returns the hostname, or the dotted quad if the
 *                 hostname lookup fails.  It will force a DNS lookup according
 *                 to the HostnameLookups setting.
 *     REMOTE_NOLOOKUP is like REMOTE_NAME except that a DNS lookup is
 *                     never forced.
 *     REMOTE_DOUBLE_REV will always force a DNS lookup, and also force
 *                   a double reverse lookup, regardless of the HostnameLookups
 *                   setting.  The result is the (double reverse checked) 
 *                   hostname, or NULL if any of the lookups fail.
 * </pre>
 * @param str_is_ip unless NULL is passed, this will be set to non-zero on output when an IP address 
 *        string is returned
 * @return The remote hostname
 * @deffunc const char *ap_get_remote_host(conn_rec *conn, void *dir_config, int type, int *str_is_ip)
 */
AP_DECLARE(const char *) ap_get_remote_host(conn_rec *conn, void *dir_config, int type, int *str_is_ip);

/**
 * Retrieve the login name of the remote user.  Undef if it could not be
 * determined
 * @param r The current request
 * @return The user logged in to the client machine
 * @deffunc const char *ap_get_remote_logname(request_rec *r)
 */
AP_DECLARE(const char *) ap_get_remote_logname(request_rec *r);

/* Used for constructing self-referencing URLs, and things like SERVER_PORT,
 * and SERVER_NAME.
 */
/**
 * build a fully qualified URL from the uri and information in the request rec
 * @param p The pool to allocate the URL from
 * @param uri The path to the requested file
 * @param r The current request
 * @return A fully qualified URL
 * @deffunc char *ap_construct_url(apr_pool_t *p, const char *uri, request_rec *r)
 */
AP_DECLARE(char *) ap_construct_url(apr_pool_t *p, const char *uri, request_rec *r);

/**
 * Get the current server name from the request
 * @param r The current request
 * @return the server name
 * @deffunc const char *ap_get_server_name(request_rec *r)
 */
AP_DECLARE(const char *) ap_get_server_name(request_rec *r);

/**
 * Get the current server port
 * @param The current request
 * @return The server's port
 * @deffunc apr_port_t ap_get_server_port(const request_rec *r)
 */
AP_DECLARE(apr_port_t) ap_get_server_port(const request_rec *r);

/**
 * Return the limit on bytes in request msg body 
 * @param r The current request
 * @return the maximum number of bytes in the request msg body
 * @deffunc apr_off_t ap_get_limit_req_body(const request_rec *r)
 */
AP_DECLARE(apr_off_t) ap_get_limit_req_body(const request_rec *r);

/**
 * Return the limit on bytes in XML request msg body
 * @param r The current request
 * @return the maximum number of bytes in XML request msg body
 * @deffunc size_t ap_get_limit_xml_body(const request_rec *r)
 */
AP_DECLARE(size_t) ap_get_limit_xml_body(const request_rec *r);

/**
 * Install a custom response handler for a given status
 * @param r The current request
 * @param status The status for which the custom response should be used
 * @param string The custom response.  This can be a static string, a file
 *               or a URL
 */
AP_DECLARE(void) ap_custom_response(request_rec *r, int status, const char *string);

/**
 * Check if the current request is beyond the configured max. number of redirects or subrequests
 * @param r The current request
 * @return true (is exceeded) or false
 * @deffunc int ap_is_recursion_limit_exceeded(const request_rec *r)
 */
AP_DECLARE(int) ap_is_recursion_limit_exceeded(const request_rec *r);

/**
 * Check for a definition from the server command line
 * @param name The define to check for
 * @return 1 if defined, 0 otherwise
 * @deffunc int ap_exists_config_define(const char *name)
 */
AP_DECLARE(int) ap_exists_config_define(const char *name);
/* FIXME! See STATUS about how */
AP_DECLARE_NONSTD(int) ap_core_translate(request_rec *r);

/* Authentication stuff.  This is one of the places where compatibility
 * with the old config files *really* hurts; they don't discriminate at
 * all between different authentication schemes, meaning that we need
 * to maintain common state for all of them in the core, and make it
 * available to the other modules through interfaces.
 */
typedef struct require_line require_line;

/** A structure to keep track of authorization requirements */
struct require_line {
    /** Where the require line is in the config file. */
    apr_int64_t method_mask;
    /** The complete string from the command line */
    char *requirement;
};
     
/**
 * Return the type of authorization required for this request
 * @param r The current request
 * @return The authorization required
 * @deffunc const char *ap_auth_type(request_rec *r)
 */
AP_DECLARE(const char *) ap_auth_type(request_rec *r);

/**
 * Return the current Authorization realm
 * @param r The current request
 * @return The current authorization realm
 * @deffunc const char *ap_auth_name(request_rec *r)
 */
AP_DECLARE(const char *) ap_auth_name(request_rec *r);     

/**
 * How the requires lines must be met.
 * @param r The current request
 * @return How the requirements must be met.  One of:
 * <pre>
 *      SATISFY_ANY    -- any of the requirements must be met.
 *      SATISFY_ALL    -- all of the requirements must be met.
 *      SATISFY_NOSPEC -- There are no applicable satisfy lines
 * </pre>
 * @deffunc int ap_satisfies(request_rec *r)
 */
AP_DECLARE(int) ap_satisfies(request_rec *r);

/**
 * Retrieve information about all of the requires directives for this request
 * @param r The current request
 * @return An array of all requires directives for this request
 * @deffunc const apr_array_header_t *ap_requires(request_rec *r)
 */
AP_DECLARE(const apr_array_header_t *) ap_requires(request_rec *r);    

#ifdef CORE_PRIVATE

/*
 * Core is also unlike other modules in being implemented in more than
 * one file... so, data structures are declared here, even though most of
 * the code that cares really is in http_core.c.  Also, another accessor.
 */

AP_DECLARE_DATA extern module core_module;

/* Per-request configuration */

typedef struct {
    /* bucket brigade used by getline for look-ahead and 
     * ap_get_client_block for holding left-over request body */
    struct apr_bucket_brigade *bb;

    /* an array of per-request working data elements, accessed
     * by ID using ap_get_request_note()
     * (Use ap_register_request_note() during initialization
     * to add elements)