Commit 290049e7 authored by Nick Kew's avatar Nick Kew
Browse files

Backport r731358/731388/731594 

mod_ext_filter: introduce sane error handling when the filter program
fails to start, including an onfail configuration option.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@732586 13f79535-47bb-0310-9956-ffa450edef68
parent 17983218

CHANGES

+5 −0
Original line number Diff line number Diff line 
                                                         -*- coding: utf-8 -*-

Changes with Apache 2.2.12



  *) mod_ext_filter: fix error handling when the filter prog fails to start,

     and introduce an onfail configuration option to abort the request

     or to remove the broken filter and continue.

     PR 41120 [Nick Kew]



  *) mod_include: support generating non-ASCII characters as entities in SSI

     PR 25202 [Nick Kew]

STATUS

+0 −7
Original line number Diff line number Diff line
@@ -86,13 +86,6 @@ RELEASE SHOWSTOPPERS: 
PATCHES ACCEPTED TO BACKPORT FROM TRUNK:

  [ start all new proposals below, under PATCHES PROPOSED. ]



  * mod_ext_filter: fix error handling when the filter prog fails to start.

    PR 41120

    http://svn.apache.org/viewvc?view=rev&revision=731358

    http://svn.apache.org/viewvc?view=rev&revision=731388

    http://svn.apache.org/viewvc?view=rev&revision=731594

    +1: niq, rpluem, covener



PATCHES PROPOSED TO BACKPORT FROM TRUNK:

  [ New proposals should be added at the end of the list ]

docs/manual/mod/mod_ext_filter.xml

+6 −0
Original line number Diff line number Diff line
@@ -340,6 +340,12 @@ delivery to the client</description> 
      messages written to standard error by the external filter

      program will be saved in the Apache error log.

      <code>NoLogStderr</code> disables this feature.</dd>



      <dt><code>Onfail=[abort|remove]</code> (new in httpd version 2.2.12).</dt>

      <dd>Determines how to proceed if the external filter program

      cannot be started.  With <code>abort</code> (the default value)

      the request will be aborted.  With <code>remove</code>, the

      filter is removed and the request continues without it.</dd>

    </dl>



    <example><title>Example</title>

modules/filters/mod_ext_filter.c

+54 −6
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ typedef struct ef_filter_t { 
typedef struct ef_dir_t {

    int debug;

    int log_stderr;

    int onfail;

} ef_dir_t;



typedef struct ef_ctx_t {
@@ -81,7 +82,6 @@ static apr_status_t ef_input_filter(ap_filter_t *, apr_bucket_brigade *, 
                                    apr_off_t);



#define DBGLVL_SHOWOPTIONS         1

#define DBGLVL_ERRORCHECK          2

#define DBGLVL_GORY                9



#define ERRFN_USERDATA_KEY         "EXTFILTCHILDERRFN"
@@ -92,6 +92,7 @@ static void *create_ef_dir_conf(apr_pool_t *p, char *dummy) 


    dc->debug = -1;

    dc->log_stderr = -1;

    dc->onfail = -1;



    return dc;

}
@@ -125,6 +126,13 @@ static void *merge_ef_dir_conf(apr_pool_t *p, void *basev, void *overridesv) 
        a->log_stderr = base->log_stderr;

    }



    if (over->onfail != -1) {   /* if admin coded something... */

        a->onfail = over->onfail;

    }

    else {

        a->onfail = base->onfail;

    }



    return a;

}
@@ -142,6 +150,12 @@ static const char *add_options(cmd_parms *cmd, void *in_dc, 
    else if (!strcasecmp(arg, "NoLogStderr")) {

        dc->log_stderr = 0;

    }

    else if (!strcasecmp(arg, "Onfail=remove")) {

        dc->onfail = 1;

    }

    else if (!strcasecmp(arg, "Onfail=abort")) {

        dc->onfail = 0;

    }

    else {

        return apr_pstrcat(cmd->temp_pool,

                           "Invalid ExtFilterOptions option: ",
@@ -449,9 +463,9 @@ static apr_status_t init_ext_filter_process(ap_filter_t *f) 
    ap_assert(rc == APR_SUCCESS);

    apr_pool_userdata_set(f->r, ERRFN_USERDATA_KEY, apr_pool_cleanup_null, ctx->p);



    if (dc->debug >= DBGLVL_ERRORCHECK) {

    rc = apr_procattr_error_check_set(ctx->procattr, 1);

        ap_assert(rc == APR_SUCCESS);

    if (rc != APR_SUCCESS) {

        return rc;

    }



    /* add standard CGI variables as well as DOCUMENT_URI, DOCUMENT_PATH_INFO,
@@ -855,7 +869,29 @@ static apr_status_t ef_output_filter(ap_filter_t *f, apr_bucket_brigade *bb) 


    if (!ctx) {

        if ((rv = init_filter_instance(f)) != APR_SUCCESS) {

            return rv;

            ctx = f->ctx;

            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,

                          "can't initialise output filter %s: %s",

                          f->frec->name,

                          (ctx->dc->onfail == 1) ? "removing" : "aborting");

            ap_remove_output_filter(f);

            if (ctx->dc->onfail == 1) {

                return ap_pass_brigade(f->next, bb);

            }

            else {

                apr_bucket *e;

                f->r->status_line = "500 Internal Server Error";



                apr_brigade_cleanup(bb);

                e = ap_bucket_error_create(HTTP_INTERNAL_SERVER_ERROR,

                                           NULL, r->pool,

                                           f->c->bucket_alloc);

                APR_BRIGADE_INSERT_TAIL(bb, e);

                e = apr_bucket_eos_create(f->c->bucket_alloc);

                APR_BRIGADE_INSERT_TAIL(bb, e);

                ap_pass_brigade(f->next, bb);

                return AP_FILTER_ERROR;

            }

        }

        ctx = f->ctx;

    }
@@ -886,7 +922,19 @@ static int ef_input_filter(ap_filter_t *f, apr_bucket_brigade *bb, 


    if (!ctx) {

        if ((rv = init_filter_instance(f)) != APR_SUCCESS) {

            return rv;

            ctx = f->ctx;

            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, f->r,

                          "can't initialise input filter %s: %s",

                          f->frec->name,

                          (ctx->dc->onfail == 1) ? "removing" : "aborting");

            ap_remove_input_filter(f);

            if (ctx->dc->onfail == 1) {

                return ap_get_brigade(f->next, bb, mode, block, readbytes);

            }

            else {

                f->r->status = HTTP_INTERNAL_SERVER_ERROR;

                return HTTP_INTERNAL_SERVER_ERROR;

            }

        }

        ctx = f->ctx;

    }