core.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。

                ap_str_tolower(conn->local_host);
            }
        }

        return conn->local_host;
    }

    /* default */
    return r->server->server_hostname;
}

/*
 * Get the current server name from the request for the purposes
 * of using in a URL.  If the server name is an IPv6 literal
 * address, it will be returned in URL format (e.g., "[fe80::1]").
 */
static const char *get_server_name_for_url(request_rec *r)
{
    const char *plain_server_name = ap_get_server_name(r);

#if APR_HAVE_IPV6
    if (ap_strchr_c(plain_server_name, ':')) { /* IPv6 literal? */
        return apr_psprintf(r->pool, "[%s]", plain_server_name);
    }
#endif
    return plain_server_name;
}

AP_DECLARE(apr_port_t) ap_get_server_port(const request_rec *r)
{
    apr_port_t port;
    core_dir_config *d =
      (core_dir_config *)ap_get_module_config(r->per_dir_config, &core_module);

    if (d->use_canonical_name == USE_CANONICAL_NAME_OFF
        || d->use_canonical_name == USE_CANONICAL_NAME_DNS) {

        /* With UseCanonicalName off Apache will form self-referential
         * URLs using the hostname and port supplied by the client if
         * any are supplied (otherwise it will use the canonical name).
         */
        port = r->parsed_uri.port_str ? r->parsed_uri.port :
               r->server->port ? r->server->port :
               ap_default_port(r);
    }
    else { /* d->use_canonical_name == USE_CANONICAL_NAME_ON */

        /* With UseCanonicalName on (and in all versions prior to 1.3)
         * Apache will use the hostname and port specified in the
         * ServerName directive to construct a canonical name for the
         * server. (If no port was specified in the ServerName
         * directive, Apache uses the port supplied by the client if
         * any is supplied, and finally the default port for the protocol
         * used.
         */
        port = r->server->port ? r->server->port :
               r->connection->local_addr->port ? r->connection->local_addr->port :
               ap_default_port(r);
    }

    /* default */
    return port;
}

AP_DECLARE(char *) ap_construct_url(apr_pool_t *p, const char *uri,
                                    request_rec *r)
{
    unsigned port = ap_get_server_port(r);
    const char *host = get_server_name_for_url(r);

    if (ap_is_default_port(port, r)) {
        return apr_pstrcat(p, ap_http_method(r), "://", host, uri, NULL);
    }

    return apr_psprintf(p, "%s://%s:%u%s", ap_http_method(r), host, port, uri);
}

AP_DECLARE(apr_off_t) ap_get_limit_req_body(const request_rec *r)
{
    core_dir_config *d =
      (core_dir_config *)ap_get_module_config(r->per_dir_config, &core_module);

    if (d->limit_req_body == AP_LIMIT_REQ_BODY_UNSET) {
        return AP_DEFAULT_LIMIT_REQ_BODY;
    }

    return d->limit_req_body;
}


/*****************************************************************
 *
 * Commands... this module handles almost all of the NCSA httpd.conf
 * commands, but most of the old srm.conf is in the the modules.
 */


/* returns a parent if it matches the given directive */
static const ap_directive_t * find_parent(const ap_directive_t *dirp,
                                          const char *what)
{
    while (dirp->parent != NULL) {
        dirp = dirp->parent;

        /* ### it would be nice to have atom-ized directives */
        if (strcasecmp(dirp->directive, what) == 0)
            return dirp;
    }

    return NULL;
}

AP_DECLARE(const char *) ap_check_cmd_context(cmd_parms *cmd,
                                              unsigned forbidden)
{
    const char *gt = (cmd->cmd->name[0] == '<'
                      && cmd->cmd->name[strlen(cmd->cmd->name)-1] != '>')
                         ? ">" : "";
    const ap_directive_t *found;

    if ((forbidden & NOT_IN_VIRTUALHOST) && cmd->server->is_virtual) {
        return apr_pstrcat(cmd->pool, cmd->cmd->name, gt,
                           " cannot occur within <VirtualHost> section", NULL);
    }

    if ((forbidden & NOT_IN_LIMIT) && cmd->limited != -1) {
        return apr_pstrcat(cmd->pool, cmd->cmd->name, gt,
                           " cannot occur within <Limit> section", NULL);
    }

    if ((forbidden & NOT_IN_DIR_LOC_FILE) == NOT_IN_DIR_LOC_FILE) {
        if (cmd->path != NULL) {
            return apr_pstrcat(cmd->pool, cmd->cmd->name, gt,
                            " cannot occur within <Directory/Location/Files> "
                            "section", NULL);
        }
        if (cmd->cmd->req_override & EXEC_ON_READ) {
            /* EXEC_ON_READ must be NOT_IN_DIR_LOC_FILE, if not, it will
             * (deliberately) segfault below in the individual tests...
             */
            return NULL;
        }
    }
    
    if (((forbidden & NOT_IN_DIRECTORY)
         && ((found = find_parent(cmd->directive, "<Directory"))
             || (found = find_parent(cmd->directive, "<DirectoryMatch"))))
        || ((forbidden & NOT_IN_LOCATION)
            && ((found = find_parent(cmd->directive, "<Location"))
                || (found = find_parent(cmd->directive, "<LocationMatch"))))
        || ((forbidden & NOT_IN_FILES)
            && ((found = find_parent(cmd->directive, "<Files"))
                || (found = find_parent(cmd->directive, "<FilesMatch"))))) {
        return apr_pstrcat(cmd->pool, cmd->cmd->name, gt,
                           " cannot occur within ", found->directive,
                           "> section", NULL);
    }

    return NULL;
}

static const char *set_access_name(cmd_parms *cmd, void *dummy,
                                   const char *arg)
{
    void *sconf = cmd->server->module_config;
    core_server_config *conf = ap_get_module_config(sconf, &core_module);

    const char *err = ap_check_cmd_context(cmd,
                                           NOT_IN_DIR_LOC_FILE|NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    conf->access_name = apr_pstrdup(cmd->pool, arg);
    return NULL;
}

#ifdef GPROF
static const char *set_gprof_dir(cmd_parms *cmd, void *dummy, const char *arg)
{
    void *sconf = cmd->server->module_config;
    core_server_config *conf = ap_get_module_config(sconf, &core_module);

    const char *err = ap_check_cmd_context(cmd,
                                           NOT_IN_DIR_LOC_FILE|NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    conf->gprof_dir = apr_pstrdup(cmd->pool, arg);
    return NULL;
}
#endif /*GPROF*/

static const char *set_add_default_charset(cmd_parms *cmd,
                                           void *d_, const char *arg)
{
    core_dir_config *d = d_;

    const char *err = ap_check_cmd_context(cmd, NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    if (!strcasecmp(arg, "Off")) {
       d->add_default_charset = ADD_DEFAULT_CHARSET_OFF;
    }
    else if (!strcasecmp(arg, "On")) {
       d->add_default_charset = ADD_DEFAULT_CHARSET_ON;
       d->add_default_charset_name = DEFAULT_ADD_DEFAULT_CHARSET_NAME;
    }
    else {
       d->add_default_charset = ADD_DEFAULT_CHARSET_ON;
       d->add_default_charset_name = arg;
    }

    return NULL;
}

static const char *set_document_root(cmd_parms *cmd, void *dummy,
                                     const char *arg)
{
    void *sconf = cmd->server->module_config;
    core_server_config *conf = ap_get_module_config(sconf, &core_module);

    const char *err = ap_check_cmd_context(cmd,
                                           NOT_IN_DIR_LOC_FILE|NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    /* TODO: ap_configtestonly && ap_docrootcheck && */
    /* XXX Shouldn't this be relative to ServerRoot ??? */
    if (apr_filepath_merge((char**)&conf->ap_document_root, NULL, arg,
                           APR_FILEPATH_TRUENAME, cmd->pool) != APR_SUCCESS
        || !ap_is_directory(cmd->pool, arg)) {
        if (cmd->server->is_virtual) {
            ap_log_perror(APLOG_MARK, APLOG_STARTUP, 0,
                          cmd->pool,
                          "Warning: DocumentRoot [%s] does not exist",
                          arg);
            conf->ap_document_root = arg;
        }
        else {
            return "DocumentRoot must be a directory";
        }
    }
    return NULL;
}

AP_DECLARE(void) ap_custom_response(request_rec *r, int status,
                                    const char *string)
{
    core_request_config *conf =
        ap_get_module_config(r->request_config, &core_module);
    int idx;

    if (conf->response_code_strings == NULL) {
        conf->response_code_strings =
            apr_pcalloc(r->pool,
                        sizeof(*conf->response_code_strings) * RESPONSE_CODES);
    }

    idx = ap_index_of_response(status);

    conf->response_code_strings[idx] =
       ((ap_is_url(string) || (*string == '/')) && (*string != '"')) ?
       apr_pstrdup(r->pool, string) : apr_pstrcat(r->pool, "\"", string, NULL);
}

static const char *set_error_document(cmd_parms *cmd, void *conf_,
                                      const char *errno_str, const char *msg)
{
    core_dir_config *conf = conf_;
    int error_number, index_number, idx500;
    enum { MSG, LOCAL_PATH, REMOTE_PATH } what = MSG;

    const char *err = ap_check_cmd_context(cmd, NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    /* 1st parameter should be a 3 digit number, which we recognize;
     * convert it into an array index
     */
    error_number = atoi(errno_str);
    idx500 = ap_index_of_response(HTTP_INTERNAL_SERVER_ERROR);

    if (error_number == HTTP_INTERNAL_SERVER_ERROR) {
        index_number = idx500;
    }
    else if ((index_number = ap_index_of_response(error_number)) == idx500) {
        return apr_pstrcat(cmd->pool, "Unsupported HTTP response code ",
                           errno_str, NULL);
    }

    /* Heuristic to determine second argument. */
    if (ap_strchr_c(msg,' '))
        what = MSG;
    else if (msg[0] == '/')
        what = LOCAL_PATH;
    else if (ap_is_url(msg))
        what = REMOTE_PATH;
    else
        what = MSG;

    /* The entry should be ignored if it is a full URL for a 401 error */

    if (error_number == 401 && what == REMOTE_PATH) {
        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, cmd->server,
                     "cannot use a full URL in a 401 ErrorDocument "
                     "directive --- ignoring!");
    }
    else { /* Store it... */
        if (conf->response_code_strings == NULL) {
            conf->response_code_strings =
                apr_pcalloc(cmd->pool,
                            sizeof(*conf->response_code_strings) *
                            RESPONSE_CODES);
        }

        if (strcmp(msg, "default") == 0) {
            /* special case: ErrorDocument 404 default restores the
             * canned server error response
             */
            conf->response_code_strings[index_number] = &errordocument_default;
        }
        else {
            /* hack. Prefix a " if it is a msg; as that is what
             * http_protocol.c relies on to distinguish between
             * a msg and a (local) path.
             */
            conf->response_code_strings[index_number] = (what == MSG) ?
                    apr_pstrcat(cmd->pool, "\"",msg,NULL) :
                    apr_pstrdup(cmd->pool, msg);
        }
    }

    return NULL;
}

static const char *set_override(cmd_parms *cmd, void *d_, const char *l)
{
    core_dir_config *d = d_;
    char *w;

    const char *err = ap_check_cmd_context(cmd, NOT_IN_LIMIT);
    if (err != NULL) {
        return err;
    }

    d->override = OR_NONE;
    while (l[0]) {
        w = ap_getword_conf(cmd->pool, &l);
        if (!strcasecmp(w, "Limit")) {
            d->override |= OR_LIMIT;
        }
        else if (!strcasecmp(w, "Options")) {
            d->override |= OR_OPTIONS;
        }
        else if (!strcasecmp(w, "FileInfo")) {
            d->override |= OR_FILEINFO;
        }
        else if (!strcasecmp(w, "AuthConfig")) {
            d->override |= OR_AUTHCFG;
        }
        else if (!strcasecmp(w, "Indexes")) {
            d->override |= OR_INDEXES;
        }
        else if (!strcasecmp(w, "None")) {
            d->override = OR_NONE;
        }
        else if (!strcasecmp(w, "All")) {
            d->override = OR_ALL;
        }
        else {
            return apr_pstrcat(cmd->pool, "Illegal override option ", w, NULL);
        }

        d->override &= ~OR_UNSET;
    }

    return NULL;
}

static const char *set_options(cmd_parms *cmd, void *d_, const char *l)
{
    core_dir_config *d = d_;
    allow_options_t opt;
    int first = 1;
    char action;

    while (l[0]) {
        char *w = ap_getword_conf(cmd->pool, &l);
        action = '\0';

        if (*w == '+' || *w == '-') {
            action = *(w++);
        }
        else if (first) {
              d->opts = OPT_NONE;
            first = 0;
        }

        if (!strcasecmp(w, "Indexes")) {
            opt = OPT_INDEXES;
        }
        else if (!strcasecmp(w, "Includes")) {
            opt = OPT_INCLUDES;
        }
        else if (!strcasecmp(w, "IncludesNOEXEC")) {
            opt = (OPT_INCLUDES | OPT_INCNOEXEC);
        }
        else if (!strcasecmp(w, "FollowSymLinks")) {
            opt = OPT_SYM_LINKS;
        }
        else if (!strcasecmp(w, "SymLinksIfOwnerMatch")) {
            opt = OPT_SYM_OWNER;
        }
        else if (!strcasecmp(w, "execCGI")) {
            opt = OPT_EXECCGI;
        }
        else if (!strcasecmp(w, "MultiViews")) {
            opt = OPT_MULTI;
        }
        else if (!strcasecmp(w, "RunScripts")) { /* AI backcompat. Yuck */
            opt = OPT_MULTI|OPT_EXECCGI;
        }
        else if (!strcasecmp(w, "None")) {
            opt = OPT_NONE;
        }
        else if (!strcasecmp(w, "All")) {
            opt = OPT_ALL;
        }
        else {
            return apr_pstrcat(cmd->pool, "Illegal option ", w, NULL);
        }

        /* we ensure the invariant (d->opts_add & d->opts_remove) == 0 */
        if (action == '-') {
            d->opts_remove |= opt;
            d->opts_add &= ~opt;
            d->opts &= ~opt;
        }
        else if (action == '+') {