mod_dav.c

最新apache的源代码

/*
 * Apache's URI escaping does not replace '&' since that is a valid character
 * in a URI (to form a query section). We must explicitly handle it so that
 * we can embed the URI into an XML document.
 */
static const char *dav_xml_escape_uri(apr_pool_t *p, const char *uri)
{
    const char *e_uri = ap_escape_uri(p, uri);

    /* check the easy case... */
    if (ap_strchr_c(e_uri, '&') == NULL)
        return e_uri;

    /* there was a '&', so more work is needed... sigh. */

    /*
     * Note: this is a teeny bit of overkill since we know there are no
     * '<' or '>' characters, but who cares.
     */
    return apr_xml_quote_string(p, e_uri, 0);
}


/* Write a complete RESPONSE object out as a <DAV:repsonse> xml
   element.  Data is sent into brigade BB, which is auto-flushed into
   OUTPUT filter stack.  Use POOL for any temporary allocations.

   [Presumably the <multistatus> tag has already been written;  this
   routine is shared by dav_send_multistatus and dav_stream_response.]
*/
static void dav_send_one_response(dav_response *response,
                                  apr_bucket_brigade *bb,
                                  ap_filter_t *output,
                                  apr_pool_t *pool)
{
    apr_text *t = NULL;

    if (response->propresult.xmlns == NULL) {
      ap_fputs(output, bb, "<D:response>");
    }
    else {
      ap_fputs(output, bb, "<D:response");
      for (t = response->propresult.xmlns; t; t = t->next) {
        ap_fputs(output, bb, t->text);
      }
      ap_fputc(output, bb, '>');
    }
    
    ap_fputstrs(output, bb,
                DEBUG_CR "<D:href>",
                dav_xml_escape_uri(pool, response->href),
                "</D:href>" DEBUG_CR,
                NULL);
    
    if (response->propresult.propstats == NULL) {
      /* use the Status-Line text from Apache.  Note, this will
       * default to 500 Internal Server Error if first->status
       * is not a known (or valid) status code.
       */
      ap_fputstrs(output, bb,
                  "<D:status>HTTP/1.1 ",
                  ap_get_status_line(response->status),
                  "</D:status>" DEBUG_CR,
                  NULL);
    }
    else {
      /* assume this includes <propstat> and is quoted properly */
      for (t = response->propresult.propstats; t; t = t->next) {
        ap_fputs(output, bb, t->text);
      }
    }
    
    if (response->desc != NULL) {
      /*
       * We supply the description, so we know it doesn't have to
       * have any escaping/encoding applied to it.
       */
      ap_fputstrs(output, bb,
                  "<D:responsedescription>",
                  response->desc,
                  "</D:responsedescription>" DEBUG_CR,
                  NULL);
    }
    
    ap_fputs(output, bb, "</D:response>" DEBUG_CR);
}


/* Factorized helper function: prep request_rec R for a multistatus
   response and write <multistatus> tag into BB, destined for
   R->output_filters.  Use xml NAMESPACES in initial tag, if
   non-NULL. */
static void dav_begin_multistatus(apr_bucket_brigade *bb,
                                  request_rec *r, int status,
                                  apr_array_header_t *namespaces)
{
    /* Set the correct status and Content-Type */
    r->status = status;
    ap_set_content_type(r, DAV_XML_CONTENT_TYPE);

    /* Send the headers and actual multistatus response now... */
    ap_fputs(r->output_filters, bb, DAV_XML_HEADER DEBUG_CR
             "<D:multistatus xmlns:D=\"DAV:\"");

    if (namespaces != NULL) {
       int i;

       for (i = namespaces->nelts; i--; ) {
           ap_fprintf(r->output_filters, bb, " xmlns:ns%d=\"%s\"", i,
                      APR_XML_GET_URI_ITEM(namespaces, i));
       }
    }

    ap_fputs(r->output_filters, bb, ">" DEBUG_CR);
}

/* Finish a multistatus response started by dav_begin_multistatus: */
static apr_status_t dav_finish_multistatus(request_rec *r,
                                           apr_bucket_brigade *bb)
{
    apr_bucket *b;
    
    ap_fputs(r->output_filters, bb, "</D:multistatus>" DEBUG_CR);
    
    /* indicate the end of the response body */
    b = apr_bucket_eos_create(r->connection->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(bb, b);

    /* deliver whatever might be remaining in the brigade */
    return ap_pass_brigade(r->output_filters, bb);
}

static void dav_send_multistatus(request_rec *r, int status,
                                 dav_response *first,
                                 apr_array_header_t *namespaces)
{
    apr_pool_t *subpool;
    apr_bucket_brigade *bb = apr_brigade_create(r->pool,
                                                r->connection->bucket_alloc);

    dav_begin_multistatus(bb, r, status, namespaces);

    apr_pool_create(&subpool, r->pool);

    for (; first != NULL; first = first->next) {
      apr_pool_clear(subpool);
      dav_send_one_response(first, bb, r->output_filters, subpool);
    }
    apr_pool_destroy(subpool);

    dav_finish_multistatus(r, bb);
}

/*
 * dav_log_err()
 *
 * Write error information to the log.
 */
static void dav_log_err(request_rec *r, dav_error *err, int level)
{
    dav_error *errscan;

    /* Log the errors */
    /* ### should have a directive to log the first or all */
    for (errscan = err; errscan != NULL; errscan = errscan->prev) {
        if (errscan->desc == NULL)
            continue;

        if (errscan->save_errno != 0) {
            errno = errscan->save_errno;
            ap_log_rerror(APLOG_MARK, level, errno, r, "%s  [%d, #%d]",
                          errscan->desc, errscan->status, errscan->error_id);
        }
        else {
            ap_log_rerror(APLOG_MARK, level, 0, r,
                          "%s  [%d, #%d]",
                          errscan->desc, errscan->status, errscan->error_id);
        }
    }
}

/*
 * dav_handle_err()
 *
 * Handle the standard error processing. <err> must be non-NULL.
 *
 * <response> is set by the following:
 *   - dav_validate_request()
 *   - dav_add_lock()
 *   - repos_hooks->remove_resource
 *   - repos_hooks->move_resource
 *   - repos_hooks->copy_resource
 *   - vsn_hooks->update
 */
static int dav_handle_err(request_rec *r, dav_error *err,
                          dav_response *response)
{
    /* log the errors */
    dav_log_err(r, err, APLOG_ERR);

    if (response == NULL) {
        dav_error *stackerr = err;

        /* our error messages are safe; tell Apache this */
        apr_table_setn(r->notes, "verbose-error-to", "*");

        /* Didn't get a multistatus response passed in, but we still
           might be able to generate a standard <D:error> response.
           Search the error stack for an errortag. */
        while (stackerr != NULL && stackerr->tagname == NULL)
            stackerr = stackerr->prev;

        if (stackerr != NULL && stackerr->tagname != NULL)
            return dav_error_response_tag(r, stackerr);

        return err->status;
    }

    /* send the multistatus and tell Apache the request/response is DONE. */
    dav_send_multistatus(r, err->status, response, NULL);
    return DONE;
}

/* handy function for return values of methods that (may) create things */
static int dav_created(request_rec *r, const char *locn, const char *what,
                       int replaced)
{
    const char *body;

    if (locn == NULL) {
        locn = r->uri;
    }

    /* did the target resource already exist? */
    if (replaced) {
        /* Apache will supply a default message */
        return HTTP_NO_CONTENT;
    }

    /* Per HTTP/1.1, S10.2.2: add a Location header to contain the
     * URI that was created. */

    /* Convert locn to an absolute URI, and return in Location header */
    apr_table_setn(r->headers_out, "Location", ap_construct_url(r->pool, locn, r));

    /* ### insert an ETag header? see HTTP/1.1 S10.2.2 */

    /* Apache doesn't allow us to set a variable body for HTTP_CREATED, so
     * we must manufacture the entire response. */
    body = apr_psprintf(r->pool, "%s %s has been created.",
                        what, ap_escape_html(r->pool, locn));
    return dav_error_response(r, HTTP_CREATED, body);
}

/* ### move to dav_util? */
DAV_DECLARE(int) dav_get_depth(request_rec *r, int def_depth)
{
    const char *depth = apr_table_get(r->headers_in, "Depth");

    if (depth == NULL) {
        return def_depth;
    }

    if (strcasecmp(depth, "infinity") == 0) {
        return DAV_INFINITY;
    }
    else if (strcmp(depth, "0") == 0) {
        return 0;
    }
    else if (strcmp(depth, "1") == 0) {
        return 1;
    }

    /* The caller will return an HTTP_BAD_REQUEST. This will augment the
     * default message that Apache provides. */
    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                  "An invalid Depth header was specified.");
    return -1;
}

static int dav_get_overwrite(request_rec *r)
{
    const char *overwrite = apr_table_get(r->headers_in, "Overwrite");

    if (overwrite == NULL) {
        return 1; /* default is "T" */
    }

    if ((*overwrite == 'F' || *overwrite == 'f') && overwrite[1] == '\0') {
        return 0;
    }

    if ((*overwrite == 'T' || *overwrite == 't') && overwrite[1] == '\0') {
        return 1;
    }

    /* The caller will return an HTTP_BAD_REQUEST. This will augment the
     * default message that Apache provides. */
    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                  "An invalid Overwrite header was specified.");
    return -1;
}

/* resolve a request URI to a resource descriptor.
 *
 * If label_allowed != 0, then allow the request target to be altered by
 * a Label: header.
 *
 * If use_checked_in is true, then the repository provider should return
 * the resource identified by the DAV:checked-in property of the resource
 * identified by the Request-URI.
 */
static dav_error *dav_get_resource(request_rec *r, int label_allowed,
                                   int use_checked_in, dav_resource **res_p)
{
    dav_dir_conf *conf;
    const char *label = NULL;
    dav_error *err;

    /* if the request target can be overridden, get any target selector */
    if (label_allowed) {
        label = apr_table_get(r->headers_in, "label");
    }

    conf = ap_get_module_config(r->per_dir_config, &dav_module);
    /* assert: conf->provider != NULL */

    /* resolve the resource */
    err = (*conf->provider->repos->get_resource)(r, conf->dir,
                                                 label, use_checked_in,
                                                 res_p);
    if (err != NULL) {
        err = dav_push_error(r->pool, err->status, 0,
                             "Could not fetch resource information.", err);
        return err;
    }

    /* Note: this shouldn't happen, but just be sure... */
    if (*res_p == NULL) {
        /* ### maybe use HTTP_INTERNAL_SERVER_ERROR */
        return dav_new_error(r->pool, HTTP_NOT_FOUND, 0,
                             apr_psprintf(r->pool,
                                          "The provider did not define a "
                                          "resource for %s.",
                                          ap_escape_html(r->pool, r->uri)));
    }

    /* ### hmm. this doesn't feel like the right place or thing to do */
    /* if there were any input headers requiring a Vary header in the response,
     * add it now */
    dav_add_vary_header(r, r, *res_p);

    return NULL;
}

static dav_error * dav_open_lockdb(request_rec *r, int ro, dav_lockdb **lockdb)
{
    const dav_hooks_locks *hooks = DAV_GET_HOOKS_LOCKS(r);

    if (hooks == NULL) {
        *lockdb = NULL;
        return NULL;
    }

    /* open the thing lazily */
    return (*hooks->open_lockdb)(r, ro, 0, lockdb);
}

static int dav_parse_range(request_rec *r,
                           apr_off_t *range_start, apr_off_t *range_end)
{
    const char *range_c;
    char *range;
    char *dash;
    char *slash;

    range_c = apr_table_get(r->headers_in, "content-range");
    if (range_c == NULL)
        return 0;

    range = apr_pstrdup(r->pool, range_c);
    if (strncasecmp(range, "bytes ", 6) != 0
        || (dash = ap_strchr(range, '-')) == NULL
        || (slash = ap_strchr(range, '/')) == NULL) {
        /* malformed header. ignore it (per S14.16 of RFC2616) */
        return 0;
    }

    *dash = *slash = '\0';

    *range_start = apr_atoi64(range + 6);