protocol.c

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。

                tmp_field = last_field + last_len - 1;
                while (tmp_field > value
                       && (*tmp_field == ' ' || *tmp_field == '\t')) {
                    *tmp_field-- = '\0';
                }

                apr_table_addn(r->headers_in, last_field, value);
                
                /* reset the alloc_len so that we'll allocate a new
                 * buffer if we have to do any more folding: we can't
                 * use the previous buffer because its contents are
                 * now part of r->headers_in
                 */
                alloc_len = 0;

            } /* end if current line is not a continuation starting with tab */
        }

        /* Found a blank line, stop. */
        if (len == 0) {
            break;
        }

        /* Keep track of this line so that we can parse it on
         * the next loop iteration.  (In the folded case, last_field
         * has been updated already.)
         */
        if (!folded) {
            last_field = field;
            last_len = len;
        }
    }

    apr_table_compress(r->headers_in, APR_OVERLAP_TABLES_MERGE);
}

AP_DECLARE(void) ap_get_mime_headers(request_rec *r)
{
    apr_bucket_brigade *tmp_bb;
    tmp_bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
    ap_get_mime_headers_core(r, tmp_bb);
    apr_brigade_destroy(tmp_bb);
}

request_rec *ap_read_request(conn_rec *conn)
{
    request_rec *r;
    apr_pool_t *p;
    const char *expect;
    int access_status;
    apr_bucket_brigade *tmp_bb;

    apr_pool_create(&p, conn->pool);
    apr_pool_tag(p, "request");
    r = apr_pcalloc(p, sizeof(request_rec));
    r->pool            = p;
    r->connection      = conn;
    r->server          = conn->base_server;

    r->user            = NULL;
    r->ap_auth_type    = NULL;

    r->allowed_methods = ap_make_method_list(p, 2);

    r->headers_in      = apr_table_make(r->pool, 25);
    r->subprocess_env  = apr_table_make(r->pool, 25);
    r->headers_out     = apr_table_make(r->pool, 12);
    r->err_headers_out = apr_table_make(r->pool, 5);
    r->notes           = apr_table_make(r->pool, 5);

    r->request_config  = ap_create_request_config(r->pool);
    /* Must be set before we run create request hook */

    r->proto_output_filters = conn->output_filters;
    r->output_filters  = r->proto_output_filters;
    r->proto_input_filters = conn->input_filters;
    r->input_filters   = r->proto_input_filters;
    ap_run_create_request(r);
    r->per_dir_config  = r->server->lookup_defaults;

    r->sent_bodyct     = 0;                      /* bytect isn't for body */

    r->read_length     = 0;
    r->read_body       = REQUEST_NO_BODY;

    r->status          = HTTP_REQUEST_TIME_OUT;  /* Until we get a request */
    r->the_request     = NULL;

    tmp_bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);

    /* Get the request... */
    if (!read_request_line(r, tmp_bb)) {
        if (r->status == HTTP_REQUEST_URI_TOO_LARGE) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "request failed: URI too long (longer than %d)", r->server->limit_req_line);
            ap_send_error_response(r, 0);
            ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
            ap_run_log_transaction(r);
            apr_brigade_destroy(tmp_bb);
            return r;
        }

        apr_brigade_destroy(tmp_bb);
        return NULL;
    }

    if (!r->assbackwards) {
        ap_get_mime_headers_core(r, tmp_bb);
        if (r->status != HTTP_REQUEST_TIME_OUT) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "request failed: error reading the headers");
            ap_send_error_response(r, 0);
            ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
            ap_run_log_transaction(r);
            apr_brigade_destroy(tmp_bb);
            return r;
        }
    }
    else {
        if (r->header_only) {
            /*
             * Client asked for headers only with HTTP/0.9, which doesn't send
             * headers! Have to dink things just to make sure the error message
             * comes through...
             */
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "client sent invalid HTTP/0.9 request: HEAD %s",
                          r->uri);
            r->header_only = 0;
            r->status = HTTP_BAD_REQUEST;
            ap_send_error_response(r, 0);
            ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
            ap_run_log_transaction(r);
            apr_brigade_destroy(tmp_bb);
            return r;
        }
    }

    apr_brigade_destroy(tmp_bb);

    r->status = HTTP_OK;                         /* Until further notice. */

    /* update what we think the virtual host is based on the headers we've
     * now read. may update status.
     */
    ap_update_vhost_from_headers(r);

    /* we may have switched to another server */
    r->per_dir_config = r->server->lookup_defaults;

    if ((!r->hostname && (r->proto_num >= HTTP_VERSION(1, 1)))
        || ((r->proto_num == HTTP_VERSION(1, 1))
            && !apr_table_get(r->headers_in, "Host"))) {
        /*
         * Client sent us an HTTP/1.1 or later request without telling us the
         * hostname, either with a full URL or a Host: header. We therefore
         * need to (as per the 1.1 spec) send an error.  As a special case,
         * HTTP/1.1 mentions twice (S9, S14.23) that a request MUST contain
         * a Host: header, and the server MUST respond with 400 if it doesn't.
         */
        r->status = HTTP_BAD_REQUEST;
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      "client sent HTTP/1.1 request without hostname "
                      "(see RFC2616 section 14.23): %s", r->uri);
    }

    if (r->status != HTTP_OK) {
        ap_send_error_response(r, 0);
        ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
        ap_run_log_transaction(r);
        return r;
    }

    if (((expect = apr_table_get(r->headers_in, "Expect")) != NULL)
        && (expect[0] != '\0')) {
        /*
         * The Expect header field was added to HTTP/1.1 after RFC 2068
         * as a means to signal when a 100 response is desired and,
         * unfortunately, to signal a poor man's mandatory extension that
         * the server must understand or return 417 Expectation Failed.
         */
        if (strcasecmp(expect, "100-continue") == 0) {
            r->expecting_100 = 1;
        }
        else {
            r->status = HTTP_EXPECTATION_FAILED;
            ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r,
                          "client sent an unrecognized expectation value of "
                          "Expect: %s", expect);
            ap_send_error_response(r, 0);
            ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
            ap_run_log_transaction(r);
            return r;
        }
    }

    ap_add_input_filter_handle(ap_http_input_filter_handle,
                               NULL, r, r->connection);

    if ((access_status = ap_run_post_read_request(r))) {
        ap_die(access_status, r);
        ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r);
        ap_run_log_transaction(r);
        return NULL;
    }

    return r;
}

/*
 * A couple of other functions which initialize some of the fields of
 * a request structure, as appropriate for adjuncts of one kind or another
 * to a request in progress.  Best here, rather than elsewhere, since
 * *someone* has to set the protocol-specific fields...
 */

AP_DECLARE(void) ap_set_sub_req_protocol(request_rec *rnew,
                                         const request_rec *r)
{
    rnew->the_request     = r->the_request;  /* Keep original request-line */

    rnew->assbackwards    = 1;   /* Don't send headers from this. */
    rnew->no_local_copy   = 1;   /* Don't try to send HTTP_NOT_MODIFIED for a
                                  * fragment. */
    rnew->method          = "GET";
    rnew->method_number   = M_GET;
    rnew->protocol        = "INCLUDED";

    rnew->status          = HTTP_OK;

    rnew->headers_in      = r->headers_in;
    rnew->subprocess_env  = apr_table_copy(rnew->pool, r->subprocess_env);
    rnew->headers_out     = apr_table_make(rnew->pool, 5);
    rnew->err_headers_out = apr_table_make(rnew->pool, 5);
    rnew->notes           = apr_table_make(rnew->pool, 5);

    rnew->expecting_100   = r->expecting_100;
    rnew->read_length     = r->read_length;
    rnew->read_body       = REQUEST_NO_BODY;

    rnew->main = (request_rec *) r;
}

static void end_output_stream(request_rec *r)
{
    conn_rec *c = r->connection;
    apr_bucket_brigade *bb;
    apr_bucket *b;

    bb = apr_brigade_create(r->pool, c->bucket_alloc);
    b = apr_bucket_eos_create(c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(bb, b);
    ap_pass_brigade(r->output_filters, bb);
}

AP_DECLARE(void) ap_finalize_sub_req_protocol(request_rec *sub)
{
    /* tell the filter chain there is no more content coming */
    if (!sub->eos_sent) {
        end_output_stream(sub);
    }
}

/* finalize_request_protocol is called at completion of sending the
 * response.  Its sole purpose is to send the terminating protocol
 * information for any wrappers around the response message body
 * (i.e., transfer encodings).  It should have been named finalize_response.
 */
AP_DECLARE(void) ap_finalize_request_protocol(request_rec *r)
{
    (void) ap_discard_request_body(r);

    /* tell the filter chain there is no more content coming */
    if (!r->eos_sent) {
        end_output_stream(r);
    }
}

/*
 * Support for the Basic authentication protocol, and a bit for Digest.
 */
AP_DECLARE(void) ap_note_auth_failure(request_rec *r)
{
    const char *type = ap_auth_type(r);
    if (type) {
        if (!strcasecmp(type, "Basic"))
            ap_note_basic_auth_failure(r);
        else if (!strcasecmp(type, "Digest"))
            ap_note_digest_auth_failure(r);
    }
    else {
        ap_log_rerror(APLOG_MARK, APLOG_ERR,
                      0, r, "need AuthType to note auth failure: %s", r->uri);
    }
}

AP_DECLARE(void) ap_note_basic_auth_failure(request_rec *r)
{
    const char *type = ap_auth_type(r);

    /* if there is no AuthType configure or it is something other than
     * Basic, let ap_note_auth_failure() deal with it
     */
    if (!type || strcasecmp(type, "Basic"))
        ap_note_auth_failure(r);
    else
        apr_table_setn(r->err_headers_out,
                       (PROXYREQ_PROXY == r->proxyreq) ? "Proxy-Authenticate"
                                                       : "WWW-Authenticate",
                       apr_pstrcat(r->pool, "Basic realm=\"", ap_auth_name(r),
                                   "\"", NULL));
}

AP_DECLARE(void) ap_note_digest_auth_failure(request_rec *r)
{
    apr_table_setn(r->err_headers_out,
                   (PROXYREQ_PROXY == r->proxyreq) ? "Proxy-Authenticate"
                                                   : "WWW-Authenticate",
                   /* need APR_TIME_T_FMT_HEX */
                   apr_psprintf(r->pool, "Digest realm=\"%s\", nonce=\"%llx\"",
                                ap_auth_name(r), r->request_time));
}

AP_DECLARE(int) ap_get_basic_auth_pw(request_rec *r, const char **pw)
{
    const char *auth_line = apr_table_get(r->headers_in,
                                          (PROXYREQ_PROXY == r->proxyreq)
                                              ? "Proxy-Authorization"
                                              : "Authorization");
    const char *t;

    if (!(t = ap_auth_type(r)) || strcasecmp(t, "Basic"))
        return DECLINED;

    if (!ap_auth_name(r)) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR,
                      0, r, "need AuthName: %s", r->uri);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    if (!auth_line) {
        ap_note_basic_auth_failure(r);
        return HTTP_UNAUTHORIZED;
    }

    if (strcasecmp(ap_getword(r->pool, &auth_line, ' '), "Basic")) {
        /* Client tried to authenticate using wrong auth scheme */
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      "client used wrong authentication scheme: %s", r->uri);
        ap_note_basic_auth_failure(r);
        return HTTP_UNAUTHORIZED;
    }

    while (*auth_line == ' ' || *auth_line == '\t') {
        auth_line++;
    }

    t = ap_pbase64decode(r->pool, auth_line);
    r->user = ap_getword_nulls (r->pool, &t, ':');
    r->ap_auth_type = "Basic";

    *pw = t;

    return OK;
}

struct content_length_ctx {
    int data_sent;  /* true if the C-L filter has already sent at
                     * least one bucket on to the next output filter
                     * for this request
                     */
};

/* This filter computes the content length, but it also computes the number
 * of bytes sent to the client.  This means that this filter will always run
 * through all of the buckets in all brigades
 */
AP_CORE_DECLARE_NONSTD(apr_status_t) ap_content_length_filter(
    ap_filter_t *f,
    apr_bucket_brigade *b)
{
    request_rec *r = f->r;
    struct content_length_ctx *ctx;
    apr_bucket *e;
    int eos = 0;