Notes from Apache HTTPD Source Code

A nameless tech company leads the world in the anti-piracy / anti-personal-privacy movement while being the 6th most cash rich in the USA. And they've given me.. $499 Upgrades of the same product 15 years in a row? I bought a laptop yesterday so my brush with piracy is still very fresh.

Don't let the economic vultures steal your dreams. Contribute to the open-source software movement.

A shortcut past difficult coding questions is by looking for someone else who's already done it. The best. So when I am dealing with technical questions that just don't have published answers.. I want to look at the code and see for myself what is going on. I almost always have one editor or another running to paste bits of code or comments I find in, to look at in more detail later. I'm all about finding solutions as fast as I can, I'm used to obstacles on the net.

For many years I learned about networking technology from the outside in. Instead of say learning about Apache by administrating servers like I do today, I learned about them in reverse. I wasn't building servers or programming daemons, I was learning about the flaws they had and what made them work.

Open source is the best learning tool on the planet, and some of the best can be found in all the various work done by Apache... Especially the Server project, which has a lonnnnnnng history of the best programmers and researchers on the planet helping to build a free product that single-handedly sparked a revolution that has powered our world the last 15 years. Free. Open Source. Copied by others. This organization is responsible in large part for the evolution of the Internet and our interaction with it daily.. Apache servers are exhanging bitts and transmitting bytes at this very second.

So I found these notes

15min ago I was asking the Apache source code for some answers for the this password plugin, and thought I'd take a break from coding and post about how open-source is such a great tool for finding the best answers to the toughest questions, for me and this site only apache can answer many of the questions and answers dealth with here.

In fact, that's exactly the reason I'm so fond of saying, Ask Apache. Just check out these Notes!

    ap_regmatch_t regmatch[AP_MAX_REG_MATCH];
    apr_array_header_t *rewriteconds;
    rewritecond_entry *conds;
    int i, rc;
    char *newuri = NULL;
    request_rec *r = ctx->r;
    int is_proxyreq = 0;

/* Information to which an extension can be mapped
typedef struct extension_info {
    char *forced_type;                /* Additional AddTyped stuff */
    char *encoding_type;              /* Added with AddEncoding... */
    char *language_type;              /* Added with AddLanguage... */
    char *handler;                    /* Added with AddHandler... */
    char *charset_type;               /* Added with AddCharset... */
    char *input_filters;              /* Added with AddInputFilter... */
    char *output_filters;             /* Added with AddOutputFilter... */

static const command_rec mime_cmds[] =
    AP_INIT_ITERATE2("AddCharset", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, charset_type), OR_FILEINFO,
        "a charset (e.g., iso-2022-jp), followed by one or more "
        "file extensions"),
    AP_INIT_ITERATE2("AddEncoding", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, encoding_type), OR_FILEINFO,
        "an encoding (e.g., gzip), followed by one or more file extensions"),
    AP_INIT_ITERATE2("AddHandler", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, handler), OR_FILEINFO,
        "a handler name followed by one or more file extensions"),
    AP_INIT_ITERATE2("AddInputFilter", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, input_filters), OR_FILEINFO,
        "input filter name (or ; delimited names) followed by one or "
        "more file extensions"),
    AP_INIT_ITERATE2("AddLanguage", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, language_type), OR_FILEINFO,
        "a language (e.g., fr), followed by one or more file extensions"),
    AP_INIT_ITERATE2("AddOutputFilter", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, output_filters), OR_FILEINFO,
        "output filter name (or ; delimited names) followed by one or "
        "more file extensions"),
    AP_INIT_ITERATE2("AddType", add_extension_info,
        (void *)APR_OFFSETOF(extension_info, forced_type), OR_FILEINFO,
        "a mime type followed by one or more file extensions"),
    AP_INIT_TAKE1("DefaultLanguage", ap_set_string_slot,
        (void*)APR_OFFSETOF(mime_dir_config, default_language), OR_FILEINFO,
        "language to use for documents with no other language file extension"),
    AP_INIT_ITERATE("MultiviewsMatch", multiviews_match, NULL, OR_FILEINFO,
        "NegotiatedOnly (default), Handlers and/or Filters, or Any"),
    AP_INIT_ITERATE("RemoveCharset", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, charset_type), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveEncoding", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, encoding_type), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveHandler", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, handler), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveInputFilter", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, input_filters), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveLanguage", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, language_type), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveOutputFilter", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, output_filters), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_ITERATE("RemoveType", remove_extension_info,
        (void *)APR_OFFSETOF(extension_info, forced_type), OR_FILEINFO,
        "one or more file extensions"),
    AP_INIT_TAKE1("TypesConfig", set_types_config, NULL, RSRC_CONF,
        "the MIME types config file"),
    AP_INIT_FLAG("ModMimeUsePathInfo", ap_set_flag_slot,
        (void *)APR_OFFSETOF(mime_dir_config, use_path_info), ACCESS_CONF,
        "Set to 'yes' to allow mod_mime to use path info for type checking"),

     *  'allowed' is a bitvector of the allowed methods.
     *  A handler must ensure that the request method is one that
     *  it is capable of handling.  Generally modules should DECLINE
     *  any request methods they do not handle.  Prior to aborting the
     *  handler like this the handler should set r->allowed to the list
     *  of methods that it is willing to handle.  This bitvector is used
     *  to construct the "Allow:" header required for OPTIONS requests,
     *  Since the default_handler deals with OPTIONS, all modules can
     *  usually decline to deal with OPTIONS.  TRACE is always allowed,
     *  modules don't need to set it explicitly.
     *  Since the default_handler will always handle a GET, a
     *  module which does *not* implement GET should probably return
     *  HTTP_METHOD_NOT_ALLOWED.  Unfortunately this means that a Script GET
     *  handler can't be installed by mod_actions.

 * @defgroup Methods List of Methods recognized by the server
 * @{
 * @brief Methods recognized (but not necessarily handled) by the server.
 * These constants are used in bit shifting masks of size int, so it is
 * unsafe to have more methods than bits in an int.  HEAD == M_GET.
 * This list must be tracked by the list in http_protocol.c in routine
 * ap_method_name_of().

#define M_GET                   0       /** RFC 2616:
#define M_PUT                   1       /*  :
#define M_POST                  2
#define M_DELETE                3
#define M_CONNECT               4
#define M_OPTIONS               5
#define M_TRACE                 6       /** RFC 2616:
#define M_PATCH                 7       /** no rfc(!)
### remove this one? */
#define M_PROPFIND              8       /** RFC 2518:
WebDAV */
#define M_PROPPATCH             9       /*  :
#define M_MKCOL                 10
#define M_COPY                  11
#define M_MOVE                  12
#define M_LOCK                  13
#define M_UNLOCK                14      /** RFC 2518:
WebDAV */
#define M_VERSION_CONTROL       15      /** RFC 3253:
WebDAV Versioning */
#define M_CHECKOUT              16      /*  :
#define M_UNCHECKOUT            17
#define M_CHECKIN               18
#define M_UPDATE                19
#define M_LABEL                 20
#define M_REPORT                21
#define M_MKWORKSPACE           22
#define M_MKACTIVITY            23
#define M_BASELINE_CONTROL      24
#define M_MERGE                 25
#define M_INVALID               26      /** RFC 3253:
WebDAV Versioning */

    methods_registry = apr_hash_make(p);
    apr_pool_cleanup_register(p, NULL,

    /* put all the standard methods into the registry hash to ease the
       mapping operations between name and number */
    register_one_method(p, "GET", M_GET);
    register_one_method(p, "PUT", M_PUT);
    register_one_method(p, "POST", M_POST);
    register_one_method(p, "DELETE", M_DELETE);
    register_one_method(p, "CONNECT", M_CONNECT);
    register_one_method(p, "OPTIONS", M_OPTIONS);
    register_one_method(p, "TRACE", M_TRACE);
    register_one_method(p, "PATCH", M_PATCH);
    register_one_method(p, "PROPFIND", M_PROPFIND);
    register_one_method(p, "PROPPATCH", M_PROPPATCH);
    register_one_method(p, "MKCOL", M_MKCOL);
    register_one_method(p, "COPY", M_COPY);
    register_one_method(p, "MOVE", M_MOVE);
    register_one_method(p, "LOCK", M_LOCK);
    register_one_method(p, "UNLOCK", M_UNLOCK);
    register_one_method(p, "VERSION-CONTROL", M_VERSION_CONTROL);
    register_one_method(p, "CHECKOUT", M_CHECKOUT);
    register_one_method(p, "UNCHECKOUT", M_UNCHECKOUT);
    register_one_method(p, "CHECKIN", M_CHECKIN);
    register_one_method(p, "UPDATE", M_UPDATE);
    register_one_method(p, "LABEL", M_LABEL);
    register_one_method(p, "REPORT", M_REPORT);
    register_one_method(p, "MKWORKSPACE", M_MKWORKSPACE);
    register_one_method(p, "MKACTIVITY", M_MKACTIVITY);
    register_one_method(p, "BASELINE-CONTROL", M_BASELINE_CONTROL);
    register_one_method(p, "MERGE", M_MERGE);

 * @defgroup HTTP_Status HTTP Status Codes
 * @{
 * The size of the static array in http_protocol.c for storing
 * all of the potential response status-lines (a sparse table).
 * A future version should dynamically generate the apr_table_t at startup.

#define HTTP_CONTINUE                      100
#define HTTP_SWITCHING_PROTOCOLS           101
#define HTTP_PROCESSING                    102
#define HTTP_OK                            200
#define HTTP_CREATED                       201
#define HTTP_ACCEPTED                      202
#define HTTP_NON_AUTHORITATIVE             203
#define HTTP_NO_CONTENT                    204
#define HTTP_RESET_CONTENT                 205
#define HTTP_PARTIAL_CONTENT               206
#define HTTP_MULTI_STATUS                  207
#define HTTP_MULTIPLE_CHOICES              300
#define HTTP_MOVED_PERMANENTLY             301
#define HTTP_MOVED_TEMPORARILY             302
#define HTTP_SEE_OTHER                     303
#define HTTP_NOT_MODIFIED                  304
#define HTTP_USE_PROXY                     305
#define HTTP_TEMPORARY_REDIRECT            307
#define HTTP_BAD_REQUEST                   400
#define HTTP_UNAUTHORIZED                  401
#define HTTP_PAYMENT_REQUIRED              402
#define HTTP_FORBIDDEN                     403
#define HTTP_NOT_FOUND                     404
#define HTTP_METHOD_NOT_ALLOWED            405
#define HTTP_NOT_ACCEPTABLE                406
#define HTTP_REQUEST_TIME_OUT              408
#define HTTP_CONFLICT                      409
#define HTTP_GONE                          410
#define HTTP_LENGTH_REQUIRED               411
#define HTTP_PRECONDITION_FAILED           412
#define HTTP_REQUEST_URI_TOO_LARGE         414
#define HTTP_RANGE_NOT_SATISFIABLE         416
#define HTTP_EXPECTATION_FAILED            417
#define HTTP_UNPROCESSABLE_ENTITY          422
#define HTTP_LOCKED                        423
#define HTTP_FAILED_DEPENDENCY             424
#define HTTP_UPGRADE_REQUIRED              426
#define HTTP_INTERNAL_SERVER_ERROR         500
#define HTTP_NOT_IMPLEMENTED               501
#define HTTP_BAD_GATEWAY                   502
#define HTTP_SERVICE_UNAVAILABLE           503
#define HTTP_GATEWAY_TIME_OUT              504
#define HTTP_VERSION_NOT_SUPPORTED         505
#define HTTP_VARIANT_ALSO_VARIES           506
#define HTTP_INSUFFICIENT_STORAGE          507
#define HTTP_NOT_EXTENDED                  510

/* The max method number. Method numbers are used to shift bitmasks,
 * so this cannot exceed 63, and all bits high is equal to -1, which is a
 * special flag, so the last bit used has index 62.

static const char * status_lines[RESPONSE_CODES] =
static const char * const status_lines[RESPONSE_CODES] =
    "100 Continue",
    "101 Switching Protocols",
    "102 Processing",
#define LEVEL_200  3
    "200 OK",
    "201 Created",
    "202 Accepted",
    "203 Non-Authoritative Information",
    "204 No Content",
    "205 Reset Content",
    "206 Partial Content",
    "207 Multi-Status",
#define LEVEL_300 11
    "300 Multiple Choices",
    "301 Moved Permanently",
    "302 Found",
    "303 See Other",
    "304 Not Modified",
    "305 Use Proxy",
    "306 unused",
    "307 Temporary Redirect",
#define LEVEL_400 19
    "400 Bad Request",
    "401 Authorization Required",
    "402 Payment Required",
    "403 Forbidden",
    "404 Not Found",
    "405 Method Not Allowed",
    "406 Not Acceptable",
    "407 Proxy Authentication Required",
    "408 Request Time-out",
    "409 Conflict",
    "410 Gone",
    "411 Length Required",
    "412 Precondition Failed",
    "413 Request Entity Too Large",
    "414 Request-URI Too Large",
    "415 Unsupported Media Type",
    "416 Requested Range Not Satisfiable",
    "417 Expectation Failed",
    "418 unused",
    "419 unused",
    "420 unused",
    "421 unused",
    "422 Unprocessable Entity",
    "423 Locked",
    "424 Failed Dependency",
    /* This is a hack, but it is required for ap_index_of_response
     * to work with 426.
    "425 No code",
    "426 Upgrade Required",
#define LEVEL_500 46
    "500 Internal Server Error",
    "501 Method Not Implemented",
    "502 Bad Gateway",
    "503 Service Temporarily Unavailable",
    "504 Gateway Time-out",
    "505 HTTP Version Not Supported",
    "506 Variant Also Negotiates",
    "507 Insufficient Storage",
    "508 unused",
    "509 unused",
    "510 Not Extended"

/** is the status code informational */
#define ap_is_HTTP_INFO(x)         (((x) >= 100)&&((x) < 200))
/** is the status code OK ?*/
#define ap_is_HTTP_SUCCESS(x)      (((x) >= 200)&&((x) < 300))
/** is the status code a redirect */
#define ap_is_HTTP_REDIRECT(x)     (((x) >= 300)&&((x) < 400))
/** is the status code a error (client or server) */
#define ap_is_HTTP_ERROR(x)        (((x) >= 400)&&((x) < 600))
/** is the status code a client error  */
#define ap_is_HTTP_CLIENT_ERROR(x) (((x) >= 400)&&((x) < 500))
/** is the status code a server error  */
#define ap_is_HTTP_SERVER_ERROR(x) (((x) >= 500)&&((x) < 600))
/** is the status code a (potentially) valid response code?  */
#define ap_is_HTTP_VALID_RESPONSE(x) (((x) >= 100)&&((x) < 600))

/** should the status code drop the connection */
#define ap_status_drops_connection(x)
                                   (((x) == HTTP_BAD_REQUEST)           ||
                                    ((x) == HTTP_REQUEST_TIME_OUT)      ||
                                    ((x) == HTTP_LENGTH_REQUIRED)       ||
                                    ((x) == HTTP_REQUEST_ENTITY_TOO_LARGE) ||
                                    ((x) == HTTP_REQUEST_URI_TOO_LARGE) ||
                                    ((x) == HTTP_INTERNAL_SERVER_ERROR) ||
                                    ((x) == HTTP_SERVICE_UNAVAILABLE) ||
                                    ((x) == HTTP_NOT_IMPLEMENTED))


 * mod_headers.c: Add/append/remove HTTP response headers
 *     Written by Paul Sutton,, 1 Oct 1996
 * The Header directive can be used to add/replace/remove HTTP headers
 * within the response message.  The RequestHeader directive can be used
 * to add/replace/remove HTTP headers before a request message is processed.

 * Valid in both per-server and per-dir configurations.
 * Syntax is:
 *   Header action header value
 *   RequestHeader action header value

 * Where action is one of:
 *     set    - set this header, replacing any old value
 *     add    - add this header, possible resulting in two or more
 *              headers with the same name
 *     append - append this text onto any existing header of this same

 *     unset  - remove this header
 * Where action is unset, the third argument (value) should not be given.
 * The header name can include the colon, or not.
 * The Header and RequestHeader directives can only be used where allowed

 * by the FileInfo override.
 * When the request is processed, the header directives are processed in
 * this order: firstly, the main server, then the virtual server handling
 * this request (if any), then any <directory> sections (working downwards

 * from the root dir), then an <location> sections (working down from
 * shortest URL component), the any <file> sections. This order is
 * important if any 'set' or 'unset' actions are used. For example,
 * the following two directives have different effect if applied in

 * the reverse order:
 *   Header append Author "John P. Doe"
 *   Header unset Author
 * Examples:

 *  To set the "Author" header, use
 *     Header add Author "John P. Doe"
 *  To remove a header:
 *     Header unset Author

    register_format_tag_handler("D", (const void *)header_request_duration);
    register_format_tag_handler("t", (const void *)header_request_time);
    register_format_tag_handler("e", (const void *)header_request_env_var);
    register_format_tag_handler("s", (const void *)header_request_ssl_var);

typedef enum {
    hdr_add = 'a',              /* add header (could mean multiple hdrs) */
    hdr_set = 's',              /* set (replace old value) */

    hdr_append = 'm',           /* append (merge into any old value) */
    hdr_unset = 'u',            /* unset header */

    hdr_echo = 'e',             /* echo headers from request to response */
    hdr_edit = 'r'              /* change value by regexp */

} hdr_actions;

 * magic cmd->info values
static char hdr_in  = '0';  /* RequestHeader */

static char hdr_out = '1';  /* Header onsuccess */
static char hdr_err = '2';  /* Header always */

 * A format string consists of white space, text and optional format
 * tags in any order. E.g.,
 * Header add MyHeader "Free form text %D %t more text"

 * Decompose the format string into its tags. Each tag (struct format_tag)
 * contains a pointer to the function used to format the tag. Then save each
 * tag in the tag array anchored in the header_entry.

        return "first argument must be 'add', 'set', 'append', 'unset', "
               "'echo' or 'edit'.";

    if (new->action == hdr_edit) {
        if (subs == NULL) {
            return "Header edit requires a match and a substitution";

 if (new->action == hdr_edit) {
        if (subs == NULL) {
            return "Header edit requires a match and a substitution";
        new->regex = ap_pregcomp(cmd->pool, value, AP_REG_EXTENDED);
        if (new->regex == NULL) {
            return "Header edit regex could not be compiled";
        new->subs = subs;
    else {
        /* there's no subs, so envclause is really that argument */

        if (envclause != NULL) {
            return "Too many arguments to directive";
        envclause = subs;
    if (new->action == hdr_unset) {
        if (value) {
            if (envclause) {
                return "header unset takes two arguments";
            envclause = value;
            value = NULL;
    else if (new->action == hdr_echo) {
        ap_regex_t *regex;

        if (value) {
            if (envclause) {
                return "Header echo takes two arguments";
            envclause = value;
            value = NULL;
        if (cmd->info != &hdr_out && cmd->info != &hdr_err)
            return "Header echo only valid on Header "

        else {
            regex = ap_pregcomp(cmd->pool, hdr, AP_REG_EXTENDED | AP_REG_NOSUB);
            if (regex == NULL) {
                return "Header echo regex could not be compiled";
        new->regex = regex;
    else if (!value)
        return "Header requires three arguments";
   /* Handle the envclause on Header */

    if (envclause != NULL) {
        if (strcasecmp(envclause, "early") == 0) {
            condition_var = condition_early;
        else {
            if (strncasecmp(envclause, "env=", 4) != 0) {
                return "error: envclause should be in the form env=envar";
            if ((envclause[4] == '')
                || ((envclause[4] == '!') && (envclause[5] == ''))) {
                return "error: missing environment variable name. "

                    "envclause should be in the form env=envar ";

    AP_INIT_RAW_ARGS("Header", header_cmd, &hdr_out, OR_FILEINFO,
                     "an optional condition, an action, header and value "
                     "followed by optional env clause"),
    AP_INIT_RAW_ARGS("RequestHeader", header_cmd, &hdr_in, OR_FILEINFO,
                     "an action, header and value followed by optional env "

    else if (!r->content_type || strcmp(r->content_type, ct)) {
        r->content_type = ct;

        /* Insert filters requested by the AddOutputFiltersByType

         * configuration directive. Content-type filters must be
         * inserted after the content handlers have run because
         * only then, do we reliably know the content-type.

/* construct and return the default error message for a given

 * HTTP defined error code
static const char *get_canned_error_string(int
                                           request_rec *r,
                                           const char *location)
    apr_pool_t *p = r->pool;
    const char *error_notes, *h1, *s1;

    switch (status) {
                           "<p>The document has moved <a href="",
                           ap_escape_html(r->pool, location),
    case HTTP_SEE_OTHER:
                           "<p>The answer to your request is located "

                           "<a href="",
                           ap_escape_html(r->pool, location),
    case HTTP_USE_PROXY:
                           "<p>This resource is only accessible "

                           "through the proxyn",
                           ap_escape_html(r->pool, location),
                           "<br />nYou will need to configure "
                           "your client to use that proxy.</p>n",
        return("<p>This server could not verify that youn"

               "are authorized to access the documentn"
               "requested.  Either you supplied the wrongn"
               "credentials (e.g., bad password), or yourn"
               "browser doesn't understand how to supplyn"

               "the credentials required.</p>n");
                                  "<p>Your browser sent a request that "
                                  "this server could not understand.<br />n",
                           "<p>You don't have permission to access ",
                           ap_escape_html(r->pool, r->uri),
                           "non this server.</p>n",
    case HTTP_NOT_FOUND:
                           "<p>The requested URL ",
                           ap_escape_html(r->pool, r->uri),
                           " was not found on this server.</p>n",
                           "<p>The requested method ", r->method,
                           " is not allowed for the URL ",
                           ap_escape_html(r->pool, r->uri),
        s1 = apr_pstrcat(p,
                         "<p>An appropriate representation of the "

                         "requested resource ",
                         ap_escape_html(r->pool, r->uri),
                         " could not be found on this server.</p>n",
        return(add_optional_notes(r, s1, "variant-list", ""));
        return(add_optional_notes(r, "", "variant-list", ""));
        s1 = apr_pstrcat(p,
                         "<p>A request of the requested method ",
                         " requires a valid Content-length.<br />n",
        return(add_optional_notes(r, s1, "error-notes", "</p>n"));
                           "<p>The precondition on the request "

                           "for the URL ",
                           ap_escape_html(r->pool, r->uri),
                           " evaluated to false.</p>n",
        s1 = apr_pstrcat(p,
                         ap_escape_html(r->pool, r->method), " to ",
                         ap_escape_html(r->pool, r->uri),
                         " not supported.<br />n",
        return(add_optional_notes(r, s1, "error-notes", "</p>n"));
        s1 = "<p>The proxy server received an invalid" CRLF
            "response from an upstream server.<br />" CRLF;
        return(add_optional_notes(r, s1, "error-notes", "</p>n"));
                           "<p>A variant for the requested "

                           ap_escape_html(r->pool, r->uri),
nis itself a negotiable resource. " "This indicates a configuration error.

n", NULL)); case HTTP_REQUEST_TIME_OUT: return("

Server timeout waiting for the HTTP request from the client.

n"); case HTTP_GONE: return(apr_pstrcat(p, "

The requested resource
", ap_escape_html(r->pool, r->uri), "
nis no longer available on this server " "and there is no forwarding address.n" "Please remove all references to this " "resource.

n", NULL)); case HTTP_REQUEST_ENTITY_TOO_LARGE: return(apr_pstrcat(p, "The requested resource
", ap_escape_html(r->pool, r->uri), "
n", "does not allow request data with ", r->method, " requests, or the amount of data provided inn" "the request exceeds the capacity limit.n", NULL)); case HTTP_REQUEST_URI_TOO_LARGE: s1 = "

The requested URL's length exceeds the capacityn" "limit for this server.
n"; return(add_optional_notes(r, s1, "error-notes", "

n")); case HTTP_UNSUPPORTED_MEDIA_TYPE: return("

The supplied request data is not in a formatn" "acceptable for processing by this resource.

n"); case HTTP_RANGE_NOT_SATISFIABLE: return("

None of the range-specifier values in the Rangen" "request-header field overlap the current extentn" "of the selected resource.

n"); case HTTP_EXPECTATION_FAILED: return(apr_pstrcat(p, "

The expectation given in the Expect " "request-header" "nfield could not be met by this server.

n" "

The client sent

n    Expect: ",
                           ap_escape_html(r->pool, apr_table_get(r->headers_in, "Expect")),
n" "but we only allow the 100-continue " "expectation.


The server understands the media type of then" "request entity, but was unable to process then" "contained instructions.

n"); case HTTP_LOCKED: return("

The requested resource is currently locked.n" "The lock must be released or proper identificationn" "given before the method can be applied.

n"); case HTTP_FAILED_DEPENDENCY: return("

The method could not be performed on the resourcen" "because the requested action depended on anothern" "action and that other action failed.

n"); case HTTP_UPGRADE_REQUIRED: return("

The requested resource can only be retrievedn" "using SSL. The server is willing to upgrade the currentn" "connection to SSL, but your client doesn't support it.n" "Either upgrade your client, or try requesting the pagen" "using https://n"); case HTTP_INSUFFICIENT_STORAGE: return("

The method could not be performed on the resourcen" "because the server is unable to store then" "representation needed to successfully complete then" "request. There is insufficient free space left inn" "your storage allocation.

n"); case HTTP_SERVICE_UNAVAILABLE: return("

The server is temporarily unable to service yourn" "request due to maintenance downtime or capacityn" "problems. Please try again later.

n"); case HTTP_GATEWAY_TIME_OUT: return("

The proxy server did not receive a timely responsen" "from the upstream server.

n"); case HTTP_NOT_EXTENDED: return("

A mandatory extension policy in the request is notn" "accepted by the server for this resource.

n"); default: /* HTTP_INTERNAL_SERVER_ERROR */ /* * This comparison to expose error-notes could be modified to * use a configuration directive and export based on that * directive. For now "*" is used to designate an error-notes * that is totally safe for any user to see (ie lacks paths, * database passwords, etc.) */ if (((error_notes = apr_table_get(r->notes, "error-notes")) != NULL) && (h1 = apr_table_get(r->notes, "verbose-error-to")) != NULL && (strcmp(h1, "*") == 0)) { return(apr_pstrcat(p, error_notes, "

n", NULL)); } else { return(apr_pstrcat(p, "

The server encountered an internal " "error orn" "misconfiguration and was unable to completen" "your request.

n" "

Please contact the server " "administrator,n ", ap_escape_html(r->pool, r->server->server_admin), " and inform them of the time the " "error occurred,n" "and anything you might have done that " "may haven" "caused the error.

n" "

More information about this error " "may be availablen" "in the server error log.

n", NULL)); } /* For all HTTP/1.x responses for which we generate the message, * we need to avoid inheriting the "normal status" header fields * that may have been set by the request handler before the * error or redirect, except for Location on external redirects. */ r->headers_out = r->err_headers_out; r->err_headers_out = tmp; apr_table_clear(r->err_headers_out); if (ap_is_HTTP_REDIRECT(status) || (status == HTTP_CREATED)) { if ((location != NULL) && *location) { apr_table_setn(r->headers_out, "Location", location); } else { location = ""; /* avoids coredump when printing, below */ } } r->content_languages = NULL; r->content_encoding = NULL; if ((status == HTTP_METHOD_NOT_ALLOWED) || (status == HTTP_NOT_IMPLEMENTED)) { apr_table_setn(r->headers_out, "Allow", make_allow(r)); } if ((custom_response = ap_response_code_string(r, idx))) { /* * We have a custom response output. This should only be * a text-string to write back. But if the ErrorDocument * was a local redirect and the requested resource failed * for any reason, the custom_response will still hold the * redirect URL. We don't really want to output this URL * as a text message, so first check the custom response * string to ensure that it is a text-string (using the * same test used in ap_die(), i.e. does it start with a "). * * If it's not a text string, we've got a recursive error or * an external redirect. If it's a recursive error, ap_die passes * us the second error code so we can write both, and has already * backed up to the original error. If it's an external redirect, * it hasn't happened yet; we may never know if it fails. */ if (custom_response[0] == '"') { ap_rputs(custom_response + 1, r); ap_finalize_request_protocol(r); return; } } { const char *title = status_lines[idx]; const char *h1; /* Accept a status_line set by a module, but only if it begins * with the 3 digit status code */ if (r->status_line != NULL && strlen(r->status_line) > 4 /* long enough */ && apr_isdigit(r->status_line[0]) && apr_isdigit(r->status_line[1]) && apr_isdigit(r->status_line[2]) && apr_isspace(r->status_line[3]) && apr_isalnum(r->status_line[4])) { title = r->status_line; } /* folks decided they didn't want the error code in the H1 text */ h1 = &title[4]; /* can't count on a charset filter being in place here, * so do ebcdic->ascii translation explicitly (if needed) */ ap_rvputs_proto_in_ascii(r, DOCTYPE_HTML_2_0 "n", title, "nn

", h1, "

n", NULL); ap_rvputs_proto_in_ascii(r, get_canned_error_string(status, r, location), NULL); if (recursive_error) { ap_rvputs_proto_in_ascii(r, "

Additionally, a ", status_lines[ap_index_of_response(recursive_error)], "nerror was encountered while trying to use an " "ErrorDocument to handle the request.

n", NULL); } ap_rvputs_proto_in_ascii(r, ap_psignature("
n", r), NULL); ap_rvputs_proto_in_ascii(r, "AskApache Web Developmentn", NULL); } ap_finalize_request_protocol(r); } static const command_rec command_table[] = { AP_INIT_FLAG( "RewriteEngine", cmd_rewriteengine, NULL, OR_FILEINFO, "On or Off to enable or disable (default) the whole " "rewriting engine"), AP_INIT_ITERATE( "RewriteOptions", cmd_rewriteoptions, NULL, OR_FILEINFO, "List of option strings to set"), AP_INIT_TAKE1( "RewriteBase", cmd_rewritebase, NULL, OR_FILEINFO, "the base URL of the per-directory context"), AP_INIT_RAW_ARGS("RewriteCond", cmd_rewritecond, NULL, OR_FILEINFO, "an input string and a to be applied regexp-pattern"), AP_INIT_RAW_ARGS("RewriteRule", cmd_rewriterule, NULL, OR_FILEINFO, "an URL-applied regexp-pattern and a substitution URL"), AP_INIT_TAKE2( "RewriteMap", cmd_rewritemap, NULL, RSRC_CONF, "a mapname and a filename"), AP_INIT_TAKE1( "RewriteLock", cmd_rewritelock, NULL, RSRC_CONF, "the filename of a lockfile used for inter-process " "synchronization"), #ifndef REWRITELOG_DISABLED AP_INIT_TAKE1( "RewriteLog", cmd_rewritelog, NULL, RSRC_CONF, "the filename of the rewriting logfile"), AP_INIT_TAKE1( "RewriteLogLevel", cmd_rewriteloglevel, NULL, RSRC_CONF, "the level of the rewriting logfile verbosity " "(0=none, 1=std, .., 9=max)"), #else AP_INIT_TAKE1( "RewriteLog", fake_rewritelog, NULL, RSRC_CONF, "[DISABLED] the filename of the rewriting logfile"), AP_INIT_TAKE1( "RewriteLogLevel", fake_rewritelog, NULL, RSRC_CONF, "[DISABLED] the level of the rewriting logfile verbosity"), #endif /* * mod_actions.c: executes scripts based on MIME type or HTTP method * * by Alexei Kosut; based on mod_cgi.c, mod_mime.c and mod_includes.c, * adapted by rst from original NCSA code by Rob McCool * * Usage instructions: * * Action mime/type /cgi-bin/script * * will activate /cgi-bin/script when a file of content type mime/type is * requested. It sends the URL and file path of the requested document using * the standard CGI PATH_INFO and PATH_TRANSLATED environment variables. * * Script PUT /cgi-bin/script * * will activate /cgi-bin/script when a request is received with the * HTTP method "PUT". The available method names are defined in httpd.h. * If the method is GET, the script will only be activated if the requested * URI includes query information (stuff after a ?-mark). */ if (!data) { char *exp_time = NULL; expires = apr_strtok(NULL, ":", &tok_cntx); path = expires ? apr_strtok(NULL, ":", &tok_cntx) : NULL; if (expires) { apr_time_exp_t tms; apr_time_exp_gmt(&tms, r->request_time + apr_time_from_sec((60 * atol(expires)))); exp_time = apr_psprintf(r->pool, "%s, %.2d-%s-%.4d " "%.2d:%.2d:%.2d GMT", apr_day_snames[tms.tm_wday], tms.tm_mday, apr_month_snames[tms.tm_mon], tms.tm_year+1900, tms.tm_hour, tms.tm_min, tms.tm_sec); } cookie = apr_pstrcat(rmain->pool, var, "=", val, "; path=", path ? path : "/", "; domain=", domain, expires ? "; expires=" : NULL, expires ? exp_time : NULL, NULL); apr_table_addn(rmain->err_headers_out, "Set-Cookie", cookie); apr_pool_userdata_set("set", notename, NULL, rmain->pool); rewritelog((rmain, 5, NULL, "setting cookie '%s'", cookie)); } else { rewritelog((rmain, 5, NULL, "skipping already set cookie '%s'", var)); } } rewriteloglevel rewritelogfile REWRITELOGFP REWRITEMAPS REWRITECONDS REWRITERULES REWRITELOCK REWRITEBASE MaxRedirects= case 'f': newcond->ptype = CONDPAT_FILE_EXISTS; break; case 's': newcond->ptype = CONDPAT_FILE_SIZE; break; case 'l': newcond->ptype = CONDPAT_FILE_LINK; break; case 'd': newcond->ptype = CONDPAT_FILE_DIR; break; case 'x': newcond->ptype = CONDPAT_FILE_XBIT; break; case 'U': newcond->ptype = CONDPAT_LU_URL; break; case 'F': newcond->ptype = CONDPAT_LU_FILE; break; case '>': newcond->ptype = CONDPAT_STR_GT; break; case '<': newcond->ptype = CONDPAT_STR_LT; break; case '=': newcond->ptype = CONDPAT_STR_EQ; /* "" represents an empty string */ C CHAIN|COOKIE E ENV F FORBIDDEN G GONE H HANDLER L LAST N NOESCAPE|NEXT|NOSUBREQ|NOCASE P PROXY|PASSTHROUGH Q QSAPPEND S SKIP T TYPE R REDIRECT (PERMANENT, TEMP, SEEOTHER) else if (apr_isdigit(*val)) { status = atoi(val); if (status != HTTP_INTERNAL_SERVER_ERROR) { int idx = ap_index_of_response(HTTP_INTERNAL_SERVER_ERROR); if (ap_index_of_response(status) == idx) { return apr_psprintf(p, "RewriteRule: invalid HTTP " "response code '%s' for " "flag 'R'", val); /* arg3: optional flags field */ newrule->forced_mimetype = NULL; newrule->forced_handler = NULL; newrule->forced_responsecode = HTTP_MOVED_TEMPORARILY; newrule->flags = RULEFLAG_NONE; newrule->env = NULL; newrule->cookie = NULL; newrule->skip = 0; case CONDPAT_LU_URL: if (*input && subreq_ok(r)) { rsub = ap_sub_req_lookup_uri(input, r, NULL); if (rsub->status < 400) { rc = 1; } rewritelog((r, 5, NULL, "RewriteCond URI (-U) check: " "path=%s -> status=%d", input, rsub->status)); ap_destroy_sub_req(rsub); } break; /* * Apply a single RewriteRule */ static int apply_rewrite_rule(rewriterule_entry *p, rewrite_ctx *ctx) { ap_regmatch_t regmatch[AP_MAX_REG_MATCH]; apr_array_header_t *rewriteconds; rewritecond_entry *conds; int i, rc; char *newuri = NULL; request_rec *r = ctx->r; int is_proxyreq = 0; ctx->uri = r->filename; if (ctx->perdir) { apr_size_t dirlen = strlen(ctx->perdir); /* * Proxy request? */ is_proxyreq = ( r->proxyreq && r->filename && !strncmp(r->filename, "proxy:", 6)); /* Since we want to match against the (so called) full URL, we have * to re-add the PATH_INFO postfix */ if (r->path_info && *r->path_info) { rewritelog((r, 3, ctx->perdir, "add path info postfix: %s -> %s%s", ctx->uri, ctx->uri, r->path_info)); ctx->uri = apr_pstrcat(r->pool, ctx->uri, r->path_info, NULL); } /* Additionally we strip the physical path from the url to match * it independent from the underlaying filesystem. */ if (!is_proxyreq && strlen(ctx->uri) >= dirlen && !strncmp(ctx->uri, ctx->perdir, dirlen)) { /* expand [E=var:val] and [CO=] */ do_expand_env(p->env, ctx); do_expand_cookie(p->cookie, ctx); /* If this rule is explicitly forced for HTTP redirection * (`RewriteRule .. .. [R]') then force an external HTTP * redirect. But make sure it is a fully-qualified URL. (If * not it is qualified with ourself). */ if (p->flags & RULEFLAG_FORCEREDIRECT) { fully_qualify_uri(r); rewritelog((r, 2, ctx->perdir, "explicitly forcing redirect with %s", r->filename)); r->status = p->forced_responsecode; return 1; } /* * The rule sets the response code (implies match-only) */ if (p->flags & RULEFLAG_STATUS) { return ACTION_STATUS; } rewrite_ssl_lookup = APR_RETRIEVE_OPTIONAL_FN(ssl_var_lookup); rewrite_is_https = APR_RETRIEVE_OPTIONAL_FN(ssl_is_https); /* * add the SCRIPT_URL variable to the env. this is a bit complicated * due to the fact that apache uses subrequests and internal redirects */ if (r->main == NULL) { var = apr_table_get(r->subprocess_env, REDIRECT_ENVVAR_SCRIPT_URL); if (var == NULL) { apr_table_setn(r->subprocess_env, ENVVAR_SCRIPT_URL, r->uri); } else { apr_table_setn(r->subprocess_env, ENVVAR_SCRIPT_URL, var); } } else { var = apr_table_get(r->main->subprocess_env, ENVVAR_SCRIPT_URL); apr_table_setn(r->subprocess_env, ENVVAR_SCRIPT_URL, var); } /* * create the SCRIPT_URI variable for the env */ /* add the canonical URI of this URL */ thisserver = ap_get_server_name(r); port = ap_get_server_port(r); if (ap_is_default_port(port, r)) { thisport = ""; } else { thisport = apr_psprintf(r->pool, ":%u", port); } thisurl = apr_table_get(r->subprocess_env, ENVVAR_SCRIPT_URL); /* now do the redirection */ apr_table_setn(r->headers_out, "Location", r->filename); rewritelog((r, 1, NULL, "redirect to %s [REDIRECT/%d]", r->filename, n)); return n; /* * Do the Options check after engine check, so * the user is able to explicitely turn RewriteEngine Off. */ if (!(ap_allow_options(r) & (OPT_SYM_LINKS | OPT_SYM_OWNER))) { /* FollowSymLinks is mandatory! */ ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Options FollowSymLinks or SymLinksIfOwnerMatch is off " "which implies that RewriteRule directive is forbidden: " "%s", r->filename); return HTTP_FORBIDDEN; } bodyoff = bodyread = apr_palloc(r->pool, bodybuf); /* only while we have enough for a chunked header */ while ((!bodylen || bodybuf >= 32) && (res = ap_get_client_block(r, bodyoff, bodybuf)) > 0) { bodylen += res; bodybuf -= res; bodyoff += res; } if (res > 0 && bodybuf < 32) { /* discard_rest_of_request_body into our buffer */ while (ap_get_client_block(r, bodyread, bodylen) > 0) ; apr_table_setn(r->notes, "error-notes", "Extended TRACE request bodies cannot exceed 64kn"); return HTTP_REQUEST_ENTITY_TOO_LARGE; } if (res < 0) { return HTTP_BAD_REQUEST; } } ap_set_content_type(r, "message/http"); /* Now we recreate the request, and echo it back */ bb = apr_brigade_create(r->pool, r->connection->bucket_alloc); apr_brigade_putstrs(bb, NULL, NULL, r->the_request, CRLF, NULL); h.pool = r->pool; if (r->status == HTTP_NOT_MODIFIED) { apr_table_do((int (*)(void *, const char *, const char *)) form_header_field, (void *) &h, r->headers_out, "Connection", "Keep-Alive", "ETag", "Content-Location", "Expires", "Cache-Control", "Vary", "Warning", "WWW-Authenticate", "Proxy-Authenticate", "Set-Cookie", "Set-Cookie2", NULL); /* Here we deal with getting the request message body from the client. * Whether or not the request contains a body is signaled by the presence * of a non-zero Content-Length or by a Transfer-Encoding: chunked. * * Note that this is more complicated than it was in Apache 1.1 and prior * versions, because chunked support means that the module does less. * * The proper procedure is this: * * 1. Call ap_setup_client_block() near the beginning of the request * handler. This will set up all the necessary properties, and will * return either OK, or an error code. If the latter, the module should * return that error code. The second parameter selects the policy to * apply if the request message indicates a body, and how a chunked * transfer-coding should be interpreted. Choose one of * * REQUEST_NO_BODY Send 413 error if message has any body * REQUEST_CHUNKED_ERROR Send 411 error if body without Content-Length * REQUEST_CHUNKED_DECHUNK If chunked, remove the chunks for me. * REQUEST_CHUNKED_PASS If chunked, pass the chunk headers with body. * * In order to use the last two options, the caller MUST provide a buffer * large enough to hold a chunk-size line, including any extensions. * * 2. When you are ready to read a body (if any), call ap_should_client_block(). * This will tell the module whether or not to read input. If it is 0, * the module should assume that there is no message body to read. * * 3. Finally, call ap_get_client_block in a loop. Pass it a buffer and its size. * It will put data into the buffer (not necessarily a full buffer), and * return the length of the input block. When it is done reading, it will * return 0 if EOF, or -1 if there was an error. * If an error occurs on input, we force an end to keepalive. * * This step also sends a 100 Continue response to HTTP/1.1 clients if appropriate. */ /* The following convoluted conditional determines whether or not * the current connection should remain persistent after this response * (a.k.a. HTTP Keep-Alive) and whether or not the output message * body should use the HTTP/1.1 chunked transfer-coding. In English, * * IF we have not marked this connection as errored; * and the response body has a defined length due to the status code * being 304 or 204, the request method being HEAD, already * having defined Content-Length or Transfer-Encoding: chunked, or * the request version being HTTP/1.1 and thus capable of being set * as chunked [we know the (r->chunked = 1) side-effect is ugly]; * and the server configuration enables keep-alive; * and the server configuration has a reasonable inter-request timeout; * and there is no maximum # requests or the max hasn't been reached; * and the response status does not require a close; * and the response generator has not already indicated close; * and the client did not request non-persistence (Connection: close); * and we haven't been configured to ignore the buggy twit * or they're a buggy twit coming through a HTTP/1.1 proxy * and the client is requesting an HTTP/1.0-style keep-alive * or the client claims to be HTTP/1.1 compliant (perhaps a proxy); * THEN we can be persistent, which requires more headers be output. * * Note that the condition evaluation order is extremely important. AP_DECLARE(int) ap_meets_conditions(request_rec *r) { const char *etag; const char *if_match, *if_modified_since, *if_unmodified, *if_nonematch; apr_time_t tmp_time; apr_int64_t mtime; int not_modified = 0; /* Check for conditional requests --- note that we only want to do * this if we are successful so far and we are not processing a * subrequest or an ErrorDocument. * * The order of the checks is important, since ETag checks are supposed * to be more accurate than checks relative to the modification time. * However, not all documents are guaranteed to *have* ETags, and some * might have Last-Modified values w/o ETags, so this gets a little * complicated. */ if (!ap_is_HTTP_SUCCESS(r->status) || r->no_local_copy) { return OK; } etag = apr_table_get(r->headers_out, "ETag"); /* All of our comparisons must be in seconds, because that's the * highest time resolution the HTTP specification allows. */ /* XXX: we should define a "time unset" constant */ tmp_time = ((r->mtime != 0) ? r->mtime : apr_time_now()); mtime = apr_time_sec(tmp_time); /* If an If-Match request-header field was given * AND the field value is not "*" (meaning match anything) * AND if our strong ETag does not match any entity tag in that field, * respond with a status of 412 (Precondition Failed). */ if ((if_match = apr_table_get(r->headers_in, "If-Match")) != NULL) { if (if_match[0] != '*' && (etag == NULL || etag[0] == 'W' || !ap_find_list_item(r->pool, if_match, etag))) { return HTTP_PRECONDITION_FAILED; } } else { /* Else if a valid If-Unmodified-Since request-header field was given * AND the requested resource has been modified since the time * specified in this field, then the server MUST * respond with a status of 412 (Precondition Failed). */ if_unmodified = apr_table_get(r->headers_in, "If-Unmodified-Since"); if (if_unmodified != NULL) { apr_time_t ius = apr_date_parse_http(if_unmodified); if ((ius != APR_DATE_BAD) && (mtime > apr_time_sec(ius))) { return HTTP_PRECONDITION_FAILED; } } } /* If an If-None-Match request-header field was given * AND the field value is "*" (meaning match anything) * OR our ETag matches any of the entity tags in that field, fail. * * If the request method was GET or HEAD, failure means the server * SHOULD respond with a 304 (Not Modified) response. * For all other request methods, failure means the server MUST * respond with a status of 412 (Precondition Failed). * * GET or HEAD allow weak etag comparison, all other methods require * strong comparison. We can only use weak if it's not a range request. */ if_nonematch = apr_table_get(r->headers_in, "If-None-Match"); if (if_nonematch != NULL) { if (r->method_number == M_GET) { if (if_nonematch[0] == '*') { not_modified = 1; } /* Build the Allow field-value from the request handler method mask. * Note that we always allow TRACE, since it is handled below. */ static char *make_allow(request_rec *r) { char *list; apr_int64_t mask; apr_array_header_t *allow = apr_array_make(r->pool, 10, sizeof(char *)); apr_hash_index_t *hi = apr_hash_first(r->pool, methods_registry); /* For TRACE below */ core_server_config *conf = ap_get_module_config(r->server->module_config, &core_module); mask = r->allowed_methods->method_mask; for (; hi; hi = apr_hash_next(hi)) { const void *key; void *val; apr_hash_this(hi, &key, NULL, &val); if ((mask & (AP_METHOD_BIT << *(int *)val)) != 0) { *(const char **)apr_array_push(allow) = key; /* the M_GET method actually refers to two methods */ if (*(int *)val == M_GET) *(const char **)apr_array_push(allow) = "HEAD"; } } /* TRACE is tested on a per-server basis */ if (conf->trace_enable != AP_TRACE_DISABLE) *(const char **)apr_array_push(allow) = "TRACE"; list = apr_array_pstrcat(r->pool, allow, ','); /* ### this is rather annoying. we should enforce registration of ### these methods */ if ((mask & (AP_METHOD_BIT << M_INVALID)) && (r->allowed_methods->method_list != NULL) && (r->allowed_methods->method_list->nelts != 0)) { int i; char **xmethod = (char **) r->allowed_methods->method_list->elts; /* * Append all of the elements of r->allowed_methods->method_list */ for (i = 0; i < r->allowed_methods->method_list->nelts; ++i) { list = apr_pstrcat(r->pool, list, ",", xmethod[i], NULL); } } return list; } AP_DECLARE(int) ap_send_http_options(request_rec *r) { if (r->assbackwards) { return DECLINED; } apr_table_setn(r->headers_out, "Allow", make_allow(r)); /* the request finalization will send an EOS, which will flush all * the headers out (including the Allow header) */ return OK; } /** * Get the server banner in a form suitable for sending over the * network, with the level of information controlled by the * ServerTokens directive. * @return The server banner */ AP_DECLARE(const char *) ap_get_server_banner(void);