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。

    conf = (core_server_config *)apr_pcalloc(a, sizeof(core_server_config));

#ifdef GPROF
    conf->gprof_dir = NULL;
#endif

    conf->access_name = is_virtual ? NULL : DEFAULT_ACCESS_FNAME;
    conf->ap_document_root = is_virtual ? NULL : DOCUMENT_LOCATION;
    conf->sec_dir = apr_array_make(a, 40, sizeof(ap_conf_vector_t *));
    conf->sec_url = apr_array_make(a, 40, sizeof(ap_conf_vector_t *));

    /* recursion stopper */
    conf->redirect_limit = 0; /* 0 == unset */
    conf->subreq_limit = 0;

    return (void *)conf;
}

static void *merge_core_server_configs(apr_pool_t *p, void *basev, void *virtv)
{
    core_server_config *base = (core_server_config *)basev;
    core_server_config *virt = (core_server_config *)virtv;
    core_server_config *conf;

    conf = (core_server_config *)apr_palloc(p, sizeof(core_server_config));
    memcpy(conf, virt, sizeof(core_server_config));

    if (!conf->access_name) {
        conf->access_name = base->access_name;
    }

    if (!conf->ap_document_root) {
        conf->ap_document_root = base->ap_document_root;
    }

    conf->sec_dir = apr_array_append(p, base->sec_dir, virt->sec_dir);
    conf->sec_url = apr_array_append(p, base->sec_url, virt->sec_url);

    conf->redirect_limit = virt->redirect_limit
                           ? virt->redirect_limit
                           : base->redirect_limit;

    conf->subreq_limit = virt->subreq_limit
                         ? virt->subreq_limit
                         : base->subreq_limit;

    return conf;
}

/* Add per-directory configuration entry (for <directory> section);
 * these are part of the core server config.
 */

AP_CORE_DECLARE(void) ap_add_per_dir_conf(server_rec *s, void *dir_config)
{
    core_server_config *sconf = ap_get_module_config(s->module_config,
                                                     &core_module);
    void **new_space = (void **)apr_array_push(sconf->sec_dir);

    *new_space = dir_config;
}

AP_CORE_DECLARE(void) ap_add_per_url_conf(server_rec *s, void *url_config)
{
    core_server_config *sconf = ap_get_module_config(s->module_config,
                                                     &core_module);
    void **new_space = (void **)apr_array_push(sconf->sec_url);

    *new_space = url_config;
}

AP_CORE_DECLARE(void) ap_add_file_conf(core_dir_config *conf, void *url_config)
{
    void **new_space = (void **)apr_array_push(conf->sec_file);

    *new_space = url_config;
}

/* We need to do a stable sort, qsort isn't stable.  So to make it stable
 * we'll be maintaining the original index into the list, and using it
 * as the minor key during sorting.  The major key is the number of
 * components (where the root component is zero).
 */
struct reorder_sort_rec {
    ap_conf_vector_t *elt;
    int orig_index;
};

static int reorder_sorter(const void *va, const void *vb)
{
    const struct reorder_sort_rec *a = va;
    const struct reorder_sort_rec *b = vb;
    core_dir_config *core_a;
    core_dir_config *core_b;

    core_a = ap_get_module_config(a->elt, &core_module);
    core_b = ap_get_module_config(b->elt, &core_module);

    /* a regex always sorts after a non-regex
     */
    if (!core_a->r && core_b->r) {
        return -1;
    }
    else if (core_a->r && !core_b->r) {
        return 1;
    }

    /* we always sort next by the number of components
     */
    if (core_a->d_components < core_b->d_components) {
        return -1;
    }
    else if (core_a->d_components > core_b->d_components) {
        return 1;
    }

    /* They have the same number of components, we now have to compare
     * the minor key to maintain the original order (from the config.)
     */
    return a->orig_index - b->orig_index;
}

void ap_core_reorder_directories(apr_pool_t *p, server_rec *s)
{
    core_server_config *sconf;
    apr_array_header_t *sec_dir;
    struct reorder_sort_rec *sortbin;
    int nelts;
    ap_conf_vector_t **elts;
    int i;
    apr_pool_t *tmp;

    sconf = ap_get_module_config(s->module_config, &core_module);
    sec_dir = sconf->sec_dir;
    nelts = sec_dir->nelts;
    elts = (ap_conf_vector_t **)sec_dir->elts;

    if (!nelts) {
        /* simple case of already being sorted... */
        /* We're not checking this condition to be fast... we're checking
         * it to avoid trying to palloc zero bytes, which can trigger some
         * memory debuggers to barf
         */
        return;
    }

    /* we have to allocate tmp space to do a stable sort */
    apr_pool_create(&tmp, p);
    sortbin = apr_palloc(tmp, sec_dir->nelts * sizeof(*sortbin));
    for (i = 0; i < nelts; ++i) {
        sortbin[i].orig_index = i;
        sortbin[i].elt = elts[i];
    }

    qsort(sortbin, nelts, sizeof(*sortbin), reorder_sorter);

    /* and now copy back to the original array */
    for (i = 0; i < nelts; ++i) {
        elts[i] = sortbin[i].elt;
    }

    apr_pool_destroy(tmp);
}

/*****************************************************************
 *
 * There are some elements of the core config structures in which
 * other modules have a legitimate interest (this is ugly, but necessary
 * to preserve NCSA back-compatibility).  So, we have a bunch of accessors
 * here...
 */

AP_DECLARE(int) ap_allow_options(request_rec *r)
{
    core_dir_config *conf =
      (core_dir_config *)ap_get_module_config(r->per_dir_config, &core_module);

    return conf->opts;
}

AP_DECLARE(int) ap_allow_overrides(request_rec *r)
{
    core_dir_config *conf;
    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->override;
}

AP_DECLARE(const char *) ap_auth_type(request_rec *r)
{
    core_dir_config *conf;

    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->ap_auth_type;
}

AP_DECLARE(const char *) ap_auth_name(request_rec *r)
{
    core_dir_config *conf;

    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->ap_auth_name;
}

AP_DECLARE(const char *) ap_default_type(request_rec *r)
{
    core_dir_config *conf;

    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->ap_default_type
               ? conf->ap_default_type
               : DEFAULT_CONTENT_TYPE;
}

AP_DECLARE(const char *) ap_document_root(request_rec *r) /* Don't use this! */
{
    core_server_config *conf;

    conf = (core_server_config *)ap_get_module_config(r->server->module_config,
                                                      &core_module);

    return conf->ap_document_root;
}

AP_DECLARE(const apr_array_header_t *) ap_requires(request_rec *r)
{
    core_dir_config *conf;

    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->ap_requires;
}

AP_DECLARE(int) ap_satisfies(request_rec *r)
{
    core_dir_config *conf;

    conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                   &core_module);

    return conf->satisfy[r->method_number];
}

/* Should probably just get rid of this... the only code that cares is
 * part of the core anyway (and in fact, it isn't publicised to other
 * modules).
 */

char *ap_response_code_string(request_rec *r, int error_index)
{
    core_dir_config *dirconf;
    core_request_config *reqconf;

    /* check for string registered via ap_custom_response() first */
    reqconf = (core_request_config *)ap_get_module_config(r->request_config,
                                                          &core_module);
    if (reqconf->response_code_strings != NULL &&
        reqconf->response_code_strings[error_index] != NULL) {
        return reqconf->response_code_strings[error_index];
    }

    /* check for string specified via ErrorDocument */
    dirconf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                      &core_module);

    if (dirconf->response_code_strings == NULL) {
	return NULL;
    }

    if (dirconf->response_code_strings[error_index] == &errordocument_default) {
        return NULL;
    }

    return dirconf->response_code_strings[error_index];
}


/* Code from Harald Hanche-Olsen <[e-mail]> */
static APR_INLINE void do_double_reverse (conn_rec *conn)
{
    apr_sockaddr_t *sa;
    apr_status_t rv;

    if (conn->double_reverse) {
        /* already done */
        return;
    }

    if (conn->remote_host == NULL || conn->remote_host[0] == '\0') {
        /* single reverse failed, so don't bother */
        conn->double_reverse = -1;
        return;
    }

    rv = apr_sockaddr_info_get(&sa, conn->remote_host, APR_UNSPEC, 0, 0, conn->pool);
    if (rv == APR_SUCCESS) {
        while (sa) {
            if (apr_sockaddr_equal(sa, conn->remote_addr)) {
                conn->double_reverse = 1;
                return;
            }

            sa = sa->next;
        }
    }

    conn->double_reverse = -1;
}

AP_DECLARE(const char *) ap_get_remote_host(conn_rec *conn, void *dir_config,
                                            int type, int *str_is_ip)
{
    int hostname_lookups;

    if (str_is_ip) { /* if caller wants to know */
        *str_is_ip = 0;
    }

    /* If we haven't checked the host name, and we want to */
    if (dir_config) {
        hostname_lookups =
            ((core_dir_config *)ap_get_module_config(dir_config, &core_module))
            ->hostname_lookups;

        if (hostname_lookups == HOSTNAME_LOOKUP_UNSET) {
            hostname_lookups = HOSTNAME_LOOKUP_OFF;
        }
    }
    else {
        /* the default */
        hostname_lookups = HOSTNAME_LOOKUP_OFF;
    }

    if (type != REMOTE_NOLOOKUP
        && conn->remote_host == NULL
        && (type == REMOTE_DOUBLE_REV
        || hostname_lookups != HOSTNAME_LOOKUP_OFF)) {

        if (apr_getnameinfo(&conn->remote_host, conn->remote_addr, 0)
            == APR_SUCCESS) {
            ap_str_tolower(conn->remote_host);

            if (hostname_lookups == HOSTNAME_LOOKUP_DOUBLE) {
                do_double_reverse(conn);
                if (conn->double_reverse != 1) {
                    conn->remote_host = NULL;
                }
            }
        }

        /* if failed, set it to the NULL string to indicate error */
        if (conn->remote_host == NULL) {
            conn->remote_host = "";
        }
    }

    if (type == REMOTE_DOUBLE_REV) {
        do_double_reverse(conn);
        if (conn->double_reverse == -1) {
            return NULL;
        }
    }

    /*
     * Return the desired information; either the remote DNS name, if found,
     * or either NULL (if the hostname was requested) or the IP address
     * (if any identifier was requested).
     */
    if (conn->remote_host != NULL && conn->remote_host[0] != '\0') {
        return conn->remote_host;
    }
    else {
        if (type == REMOTE_HOST || type == REMOTE_DOUBLE_REV) {
            return NULL;
        }
        else {
            if (str_is_ip) { /* if caller wants to know */
                *str_is_ip = 1;
            }

            return conn->remote_ip;
        }
    }
}

AP_DECLARE(const char *) ap_get_remote_logname(request_rec *r)
{
    core_dir_config *dir_conf;

    if (r->connection->remote_logname != NULL) {
        return r->connection->remote_logname;
    }

    /* If we haven't checked the identity, and we want to */
    dir_conf = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                       &core_module);

    if (dir_conf->do_rfc1413 & 1) {
        return ap_rfc1413(r->connection, r->server);
    }
    else {
        return NULL;
    }
}

/* There are two options regarding what the "name" of a server is.  The
 * "canonical" name as defined by ServerName and Port, or the "client's
 * name" as supplied by a possible Host: header or full URI.  We never
 * trust the port passed in the client's headers, we always use the
 * port of the actual socket.
 *
 * The DNS option to UseCanonicalName causes this routine to do a
 * reverse lookup on the local IP address of the connection and use
 * that for the ServerName. This makes its value more reliable while
 * at the same time allowing Demon's magic virtual hosting to work.
 * The assumption is that DNS lookups are sufficiently quick...
 * -- fanf 1998-10-03
 */
AP_DECLARE(const char *) ap_get_server_name(request_rec *r)
{
    conn_rec *conn = r->connection;
    core_dir_config *d;

    d = (core_dir_config *)ap_get_module_config(r->per_dir_config,
                                                &core_module);

    if (d->use_canonical_name == USE_CANONICAL_NAME_OFF) {
        return r->hostname ? r->hostname : r->server->server_hostname;
    }

    if (d->use_canonical_name == USE_CANONICAL_NAME_DNS) {
        if (conn->local_host == NULL) {
            if (apr_getnameinfo(&conn->local_host,
                                conn->local_addr, 0) != APR_SUCCESS)
                conn->local_host = apr_pstrdup(conn->pool,
                                               r->server->server_hostname);
            else {