http_config.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_CONFIG_H
#define APACHE_HTTP_CONFIG_H

#include "apr_hooks.h"
#include "util_cfgtree.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @file http_config.h
 * @brief Apache Configuration
 */

/*
 * The central data structures around here...
 */

/* Command dispatch structures... */

/**
 * How the directives arguments should be parsed.
 * @remark Note that for all of these except RAW_ARGS, the config routine is
 *      passed a freshly allocated string which can be modified or stored
 *      or whatever...
 */
enum cmd_how {
    RAW_ARGS,			/**< cmd_func parses command line itself */
    TAKE1,			/**< one argument only */
    TAKE2,			/**< two arguments only */
    ITERATE,			/**< one argument, occuring multiple times
				 * (e.g., IndexIgnore)
				 */
    ITERATE2,			/**< two arguments, 2nd occurs multiple times
				 * (e.g., AddIcon)
				 */
    FLAG,			/**< One of 'On' or 'Off' */
    NO_ARGS,			/**< No args at all, e.g. </Directory> */
    TAKE12,			/**< one or two arguments */
    TAKE3,			/**< three arguments only */
    TAKE23,			/**< two or three arguments */
    TAKE123,			/**< one, two or three arguments */
    TAKE13			/**< one or three arguments */
};
/**
 * This structure is passed to a command which is being invoked,
 * to carry a large variety of miscellaneous data which is all of
 * use to *somebody*...
 */
typedef struct cmd_parms_struct cmd_parms;

#if defined(AP_HAVE_DESIGNATED_INITIALIZER) || defined(DOXYGEN)

/** 
 * All the types of functions that can be used in directives
 * @internal
 */
typedef union {
    /** function to call for a no-args */
    const char *(*no_args) (cmd_parms *parms, void *mconfig);
    /** function to call for a raw-args */
    const char *(*raw_args) (cmd_parms *parms, void *mconfig,
			     const char *args);
    /** function to call for a take1 */
    const char *(*take1) (cmd_parms *parms, void *mconfig, const char *w);
    /** function to call for a take2 */
    const char *(*take2) (cmd_parms *parms, void *mconfig, const char *w,
			  const char *w2);
    /** function to call for a take3 */
    const char *(*take3) (cmd_parms *parms, void *mconfig, const char *w,
			  const char *w2, const char *w3);
    /** function to call for a flag */
    const char *(*flag) (cmd_parms *parms, void *mconfig, int on);
} cmd_func;

/** This configuration directive does not take any arguments */
# define AP_NO_ARGS	func.no_args
/** This configuration directive will handle it's own parsing of arguments*/
# define AP_RAW_ARGS	func.raw_args
/** This configuration directive takes 1 argument*/
# define AP_TAKE1	func.take1
/** This configuration directive takes 2 arguments */
# define AP_TAKE2	func.take2
/** This configuration directive takes 3 arguments */
# define AP_TAKE3	func.take3
/** This configuration directive takes a flag (on/off) as a argument*/
# define AP_FLAG	func.flag

/** method of declaring a directive with no arguments */
# define AP_INIT_NO_ARGS(directive, func, mconfig, where, help) \
    { directive, { .no_args=func }, mconfig, where, RAW_ARGS, help }
/** method of declaring a directive with raw argument parsing */
# define AP_INIT_RAW_ARGS(directive, func, mconfig, where, help) \
    { directive, { .raw_args=func }, mconfig, where, RAW_ARGS, help }
/** method of declaring a directive which takes 1 argument */
# define AP_INIT_TAKE1(directive, func, mconfig, where, help) \
    { directive, { .take1=func }, mconfig, where, TAKE1, help }
/** method of declaring a directive which takes multiple arguments */
# define AP_INIT_ITERATE(directive, func, mconfig, where, help) \
    { directive, { .take1=func }, mconfig, where, ITERATE, help }
/** method of declaring a directive which takes 2 arguments */
# define AP_INIT_TAKE2(directive, func, mconfig, where, help) \
    { directive, { .take2=func }, mconfig, where, TAKE2, help }
/** method of declaring a directive which takes 1 or 2 arguments */
# define AP_INIT_TAKE12(directive, func, mconfig, where, help) \
    { directive, { .take2=func }, mconfig, where, TAKE12, help }
/** method of declaring a directive which takes multiple 2 arguments */
# define AP_INIT_ITERATE2(directive, func, mconfig, where, help) \
    { directive, { .take2=func }, mconfig, where, ITERATE2, help }
/** method of declaring a directive which takes 1 or 3 arguments */
# define AP_INIT_TAKE13(directive, func, mconfig, where, help) \
    { directive, { .take3=func }, mconfig, where, TAKE13, help }
/** method of declaring a directive which takes 2 or 3 arguments */
# define AP_INIT_TAKE23(directive, func, mconfig, where, help) \
    { directive, { .take3=func }, mconfig, where, TAKE23, help }
/** method of declaring a directive which takes 1 to 3 arguments */
# define AP_INIT_TAKE123(directive, func, mconfig, where, help) \
    { directive, { .take3=func }, mconfig, where, TAKE123, help }
/** method of declaring a directive which takes 3 arguments */
# define AP_INIT_TAKE3(directive, func, mconfig, where, help) \
    { directive, { .take3=func }, mconfig, where, TAKE3, help }
/** method of declaring a directive which takes a flag (on/off) as a argument*/
# define AP_INIT_FLAG(directive, func, mconfig, where, help) \
    { directive, { .flag=func }, mconfig, where, FLAG, help }

#else /* AP_HAVE_DESIGNATED_INITIALIZER */

typedef const char *(*cmd_func) ();

# define AP_NO_ARGS  func
# define AP_RAW_ARGS func
# define AP_TAKE1    func
# define AP_TAKE2    func
# define AP_TAKE3    func
# define AP_FLAG     func

# define AP_INIT_NO_ARGS(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, RAW_ARGS, help }
# define AP_INIT_RAW_ARGS(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, RAW_ARGS, help }
# define AP_INIT_TAKE1(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE1, help }
# define AP_INIT_ITERATE(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, ITERATE, help }
# define AP_INIT_TAKE2(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE2, help }
# define AP_INIT_TAKE12(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE12, help }
# define AP_INIT_ITERATE2(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, ITERATE2, help }
# define AP_INIT_TAKE13(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE13, help }
# define AP_INIT_TAKE23(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE23, help }
# define AP_INIT_TAKE123(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE123, help }
# define AP_INIT_TAKE3(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, TAKE3, help }
# define AP_INIT_FLAG(directive, func, mconfig, where, help) \
    { directive, func, mconfig, where, FLAG, help }

#endif /* AP_HAVE_DESIGNATED_INITIALIZER */

/**
 * The command record structure.  Each modules can define a table of these
 * to define the directives it will implement.
 */
typedef struct command_struct command_rec; 
struct command_struct {
    /** Name of this command */
    const char *name;
    /** The function to be called when this directive is parsed */
    cmd_func func;
    /** Extra data, for functions which implement multiple commands... */
    void *cmd_data;		
    /** What overrides need to be allowed to enable this command. */
    int req_override;
    /** What the command expects as arguments 
     *  @defvar cmd_how args_how*/
    enum cmd_how args_how;

    /** 'usage' message, in case of syntax errors */
    const char *errmsg;
};

/**
 * @defgroup ConfigDirectives Allowed locations for configuration directives.
 *
 * The allowed locations for a configuration directive are the union of
 * those indicated by each set bit in the req_override mask.
 *
 * @{
 */
#define OR_NONE 0             /**< *.conf is not available anywhere in this override */
#define OR_LIMIT 1	     /**< *.conf inside <Directory> or <Location>
				and .htaccess when AllowOverride Limit */
#define OR_OPTIONS 2         /**< *.conf anywhere
                                and .htaccess when AllowOverride Options */
#define OR_FILEINFO 4        /**< *.conf anywhere
				and .htaccess when AllowOverride FileInfo */
#define OR_AUTHCFG 8         /**< *.conf inside <Directory> or <Location>
				and .htaccess when AllowOverride AuthConfig */
#define OR_INDEXES 16        /**< *.conf anywhere
				and .htaccess when AllowOverride Indexes */
#define OR_UNSET 32          /**< unset a directive (in Allow) */
#define ACCESS_CONF 64       /**< *.conf inside <Directory> or <Location> */
#define RSRC_CONF 128	     /**< *.conf outside <Directory> or <Location> */
#define EXEC_ON_READ 256     /**< force directive to execute a command 
                which would modify the configuration (like including another
                file, or IFModule */
/** this directive can be placed anywhere */
#define OR_ALL (OR_LIMIT|OR_OPTIONS|OR_FILEINFO|OR_AUTHCFG|OR_INDEXES)

/** @} */

/**
 * This can be returned by a function if they don't wish to handle
 * a command. Make it something not likely someone will actually use
 * as an error code.
 */
#define DECLINE_CMD "\a\b"

/** Common structure for reading of config files / passwd files etc. */
typedef struct ap_configfile_t ap_configfile_t;
struct ap_configfile_t {
    int (*getch) (void *param);	    /**< a getc()-like function */
    void *(*getstr) (void *buf, size_t bufsiz, void *param);
				    /**< a fgets()-like function */
    int (*close) (void *param);	    /**< a close handler function */
    void *param;                    /**< the argument passed to getch/getstr/close */
    const char *name;               /**< the filename / description */
    unsigned line_number;           /**< current line number, starting at 1 */
};

/**
 * This structure is passed to a command which is being invoked,
 * to carry a large variety of miscellaneous data which is all of
 * use to *somebody*...
 */
struct cmd_parms_struct {
    /** Argument to command from cmd_table */
    void *info;
    /** Which allow-override bits are set */
    int override;
    /** Which methods are <Limit>ed */
    apr_int64_t limited;
    /** methods which are limited */
    apr_array_header_t *limited_xmethods;
    /** methods which are xlimited */
    ap_method_list_t *xlimited;

    /** Config file structure. */
    ap_configfile_t *config_file;
    /** the directive specifying this command */
    ap_directive_t *directive;

    /** Pool to allocate new storage in */
    apr_pool_t *pool;
    /** Pool for scratch memory; persists during configuration, but 
     *  wiped before the first request is served...  */
    apr_pool_t *temp_pool;
    /** Server_rec being configured for */
    server_rec *server;
    /** If configuring for a directory, pathname of that directory.  
     *  NOPE!  That's what it meant previous to the existance of <Files>, 
     * <Location> and regex matching.  Now the only usefulness that can be 
     * derived from this field is whether a command is being called in a 
     * server context (path == NULL) or being called in a dir context 
     * (path != NULL).  */
    char *path;
    /** configuration command */
    const command_rec *cmd;

    /** per_dir_config vector passed to handle_command */
    struct ap_conf_vector_t *context;
    /** directive with syntax error */
    const ap_directive_t *err_directive;
};

/**
 * Module structures.  Just about everything is dispatched through
 * these, directly or indirectly (through the command and handler
 * tables).
 */
typedef struct module_struct module;
struct module_struct {
    /** API version, *not* module version; check that module is 
     * compatible with this version of the server.
     */
    int version;
    /** API minor version. Provides API feature milestones. Not checked 
     *  during module init */
    int minor_version;
    /** Index to this modules structures in config vectors.  */
    int module_index;

    /** The name of the module's C file */
    const char *name;
    /** The handle for the DSO.  Internal use only */
    void *dynamic_load_handle;

    /** A pointer to the next module in the list
     *  @defvar module_struct *next */
    struct module_struct *next;

    /** Magic Cookie to identify a module structure;  It's mainly 
     *  important for the DSO facility (see also mod_so).  */
    unsigned long magic;

    /** Function to allow MPMs to re-write command line arguments.  This
     *  hook is only available to MPMs.
     *  @param The process that the server is running in.
     */
    void (*rewrite_args) (process_rec *process);
    /** Function to allow all modules to create per directory configuration
     *  structures.
     *  @param p The pool to use for all allocations.
     *  @param dir The directory currently being processed.
     *  @return The per-directory structure created
     */
    void *(*create_dir_config) (apr_pool_t *p, char *dir);
    /** Function to allow all modules to merge the per directory configuration
     *  structures for two directories.