text: /* 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.
   */
  
  /**
   * @file  util_fcgi.h
   * @brief FastCGI protocol definitions and support routines
   *
   * @defgroup APACHE_CORE_FASTCGI FastCGI Tools
   * @ingroup  APACHE_CORE
   * @{
   */
  
  #ifndef APACHE_UTIL_FCGI_H
  #define APACHE_UTIL_FCGI_H
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include "httpd.h"
  
  /**
   * @brief A structure that represents the fixed header fields
   * at the beginning of a "FastCGI record" (i.e., the data prior
   * to content data and padding).
   */
  typedef struct {
      /** See values for version, below */
      unsigned char version;
      /** See values for type, below */
      unsigned char type;
      /** request id, in two parts */
      unsigned char requestIdB1;
      unsigned char requestIdB0;
      /** content length, in two parts */
      unsigned char contentLengthB1;
      unsigned char contentLengthB0;
      /** padding length */
      unsigned char paddingLength;
      /** 8-bit reserved field */
      unsigned char reserved;
  } ap_fcgi_header;
  
  /*
   * Number of bytes in the header portion of a FastCGI record
   * (i.e., ap_fcgi_header structure).  Future versions of the
   * protocol may increase the size.
   */
  #define AP_FCGI_HEADER_LEN  8
  
  /*
   * Maximum number of bytes in the content portion of a FastCGI record.
   */
  #define AP_FCGI_MAX_CONTENT_LEN 65535
  
  /**
   * Possible values for the version field of ap_fcgi_header
   */
  #define AP_FCGI_VERSION_1 1
  
  /**
   * Possible values for the type field of ap_fcgi_header
   */
  #define AP_FCGI_BEGIN_REQUEST       1
  #define AP_FCGI_ABORT_REQUEST       2
  #define AP_FCGI_END_REQUEST         3
  #define AP_FCGI_PARAMS              4
  #define AP_FCGI_STDIN               5
  #define AP_FCGI_STDOUT              6
  #define AP_FCGI_STDERR              7
  #define AP_FCGI_DATA                8
  #define AP_FCGI_GET_VALUES          9
  #define AP_FCGI_GET_VALUES_RESULT  10
  #define AP_FCGI_UNKNOWN_TYPE       11
  #define AP_FCGI_MAXTYPE (AP_FCGI_UNKNOWN_TYPE)
  
  /**
   * Offsets of the various fields of ap_fcgi_header
   */
  #define AP_FCGI_HDR_VERSION_OFFSET         0
  #define AP_FCGI_HDR_TYPE_OFFSET            1
  #define AP_FCGI_HDR_REQUEST_ID_B1_OFFSET   2
  #define AP_FCGI_HDR_REQUEST_ID_B0_OFFSET   3
  #define AP_FCGI_HDR_CONTENT_LEN_B1_OFFSET  4
  #define AP_FCGI_HDR_CONTENT_LEN_B0_OFFSET  5
  #define AP_FCGI_HDR_PADDING_LEN_OFFSET     6
  #define AP_FCGI_HDR_RESERVED_OFFSET        7
  
  /**
   * @brief This represents the content data of the FastCGI record when
   * the type is AP_FCGI_BEGIN_REQUEST.
   */
  typedef struct {
      /**
       * role, in two parts
       * See values for role, below
       */
      unsigned char roleB1;
      unsigned char roleB0;
      /**
       * flags
       * See values for flags bits, below
       */
      unsigned char flags;
      /** reserved */
      unsigned char reserved[5];
  } ap_fcgi_begin_request_body;
  
  /*
   * Values for role component of ap_fcgi_begin_request_body
   */
  #define AP_FCGI_RESPONDER  1
  #define AP_FCGI_AUTHORIZER 2
  #define AP_FCGI_FILTER     3
  
  /*
   * Values for flags bits of ap_fcgi_begin_request_body
   */
  #define AP_FCGI_KEEP_CONN  1  /* otherwise the application closes */
  
  /**
   * Offsets of the various fields of ap_fcgi_begin_request_body
   */
  #define AP_FCGI_BRB_ROLEB1_OFFSET       0
  #define AP_FCGI_BRB_ROLEB0_OFFSET       1
  #define AP_FCGI_BRB_FLAGS_OFFSET        2
  #define AP_FCGI_BRB_RESERVED0_OFFSET    3
  #define AP_FCGI_BRB_RESERVED1_OFFSET    4
  #define AP_FCGI_BRB_RESERVED2_OFFSET    5
  #define AP_FCGI_BRB_RESERVED3_OFFSET    6
  #define AP_FCGI_BRB_RESERVED4_OFFSET    7
  
  /**
   * Pack ap_fcgi_header
   * @param h The header to read from
   * @param a The array to write to, of size AP_FCGI_HEADER_LEN
   */
  AP_DECLARE(void) ap_fcgi_header_to_array(ap_fcgi_header *h,
                                           unsigned char a[]);
  
  /**
   * Unpack header of FastCGI record into ap_fcgi_header
   * @param h The header to write to
   * @param a The array to read from, of size AP_FCGI_HEADER_LEN
   */
  AP_DECLARE(void) ap_fcgi_header_from_array(ap_fcgi_header *h,
                                             unsigned char a[]);
  
  /**
   * Unpack header of FastCGI record into individual fields
   * @param version The version, on output
   * @param type The type, on output
   * @param request_id The request id, on output
   * @param content_len The content length, on output
   * @param padding_len The amount of padding following the content, on output
   * @param a The array to read from, of size AP_FCGI_HEADER_LEN
   */
  AP_DECLARE(void) ap_fcgi_header_fields_from_array(unsigned char *version,
                                                    unsigned char *type,
                                                    apr_uint16_t *request_id,
                                                    apr_uint16_t *content_len,
                                                    unsigned char *padding_len,
                                                    unsigned char a[]);
  
  /**
   * Pack ap_fcgi_begin_request_body
   * @param h The begin-request body to read from
   * @param a The array to write to, of size AP_FCGI_HEADER_LEN
   */
  AP_DECLARE(void) ap_fcgi_begin_request_body_to_array(ap_fcgi_begin_request_body *h,
                                                       unsigned char a[]);
  
  /**
   * Fill in a FastCGI request header with the required field values.
   * @param header The header to fill in
   * @param type The type of record
   * @param request_id The request id
   * @param content_len The amount of content which follows the header
   * @param padding_len The amount of padding which follows the content
   *
   * The header array must be at least AP_FCGI_HEADER_LEN bytes long.
   */
  AP_DECLARE(void) ap_fcgi_fill_in_header(ap_fcgi_header *header,
                                          unsigned char type,
                                          apr_uint16_t request_id,
                                          apr_uint16_t content_len,
                                          unsigned char padding_len);
  
  /**
   * Fill in a FastCGI begin request body with the required field values.
   * @param brb The begin-request-body to fill in
   * @param role AP_FCGI_RESPONDER or other roles
   * @param flags 0 or a combination of flags like AP_FCGI_KEEP_CONN
   */
  AP_DECLARE(void) ap_fcgi_fill_in_request_body(ap_fcgi_begin_request_body *brb,
                                                int role,
                                                unsigned char flags);
  
  /**
   * Compute the buffer size needed to encode the next portion of
   * the provided environment table.
   * @param env The environment table
   * @param maxlen The maximum buffer size allowable, capped at 
   * AP_FCGI_MAX_CONTENT_LEN.
   * @param starting_elem On input, the next element of the table array
   * to process in this FastCGI record.  On output, the next element to
   * process on the *next* FastCGI record.
   * @return Size of buffer needed to encode the next part, or 0
   * if no more can be encoded.  When 0 is returned: If starting_elem
   * has reached the end of the table array, all has been encoded;
   * otherwise, the next envvar can't be encoded within the specified
   * limit.
   * @note If an envvar can't be encoded within the specified limit,
   * the caller can log a warning and increment starting_elem and try 
   * again or increase the limit or fail, as appropriate for the module.
   */
  AP_DECLARE(apr_size_t) ap_fcgi_encoded_env_len(apr_table_t *env,
                                                 apr_size_t maxlen,
                                                 int *starting_elem);
  
  /**
   * Encode the next portion of the provided environment table using
   * a buffer previously allocated.
   * @param r The request, for logging
   * @param env The environment table
   * @param buffer A buffer to contain the encoded environment table
   * @param buflen The length of the buffer, previously computed by
   * ap_fcgi_encoded_env_len().
   * @param starting_elem On input, the next element of the table array
   * to process in this FastCGI record.  On output, the next element to
   * process on the *next* FastCGI record.
   * @return APR_SUCCESS if a section could be encoded or APR_ENOSPC
   * otherwise.
   * @note The output starting_elem from ap_fcgi_encoded_env_len
   * shouldn't be used as input to ap_fcgi_encode_env when building the
   * same FastCGI record.
   */
  AP_DECLARE(apr_status_t) ap_fcgi_encode_env(request_rec *r,
                                              apr_table_t *env,
                                              void *buffer,
                                              apr_size_t buflen,
                                              int *starting_elem);
  
  /**
   * String forms for the value of the FCGI_ROLE envvar
   */
  #define AP_FCGI_RESPONDER_STR   "RESPONDER"
  #define AP_FCGI_AUTHORIZER_STR  "AUTHORIZER"
  #define AP_FCGI_FILTER_STR      "FILTER"
  
  /**
   * FastCGI implementations that implement the AUTHORIZER role
   * for Apache httpd and allow the application to participate in
   * any of the Apache httpd AAA phases typically set the variable
   * FCGI_APACHE_ROLE to one of these strings to indicate the
   * specific AAA phase.
   */
  #define AP_FCGI_APACHE_ROLE_AUTHENTICATOR_STR  "AUTHENTICATOR"
  #define AP_FCGI_APACHE_ROLE_AUTHORIZER_STR     "AUTHORIZER"
  #define AP_FCGI_APACHE_ROLE_ACCESS_CHECKER_STR "ACCESS_CHECKER"
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif  /* !APACHE_UTIL_FCGI_H */
  /** @} */
  