Commit 0f272dbb authored by Yann Ylavic's avatar Yann Ylavic
Browse files

mod_slotmem_shm: generation number for SHM filename on all platforms. 

This effectively restores r1822341 which was reverted by r1822505.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1831869 13f79535-47bb-0310-9956-ffa450edef68
parent 045485ee

CHANGES

+3 −0
Changes for CHANGES: 3 added lines, 0 removed lines.
Original line number Diff line number Diff line 
                                                         -*- coding: utf-8 -*-

Changes with Apache 2.5.1



  *) mod_slotmem_shm: Add generation number to shm filename to fix races

     with graceful restarts. PR 62044.  [Jim Jagielski, Yann Ylavic]



  *) mod_rewrite: Only create the global mutex used by "RewriteMap prg:" when

     this type of map is present in the configuration.  PR62311.  

     [Hank Ibell <hwibell gmail.com>]

modules/slotmem/mod_slotmem_shm.c

+3 −36
Changes for modules/slotmem/mod_slotmem_shm.c: 3 added lines, 36 removed lines.
Original line number Diff line number Diff line
@@ -71,31 +71,6 @@ static apr_pool_t *gpool = NULL; 
#define DEFAULT_SLOTMEM_SUFFIX ".shm"

#define DEFAULT_SLOTMEM_PERSIST_SUFFIX ".persist"



/* Unixes (and Netware) have the unlink() semantic, which allows to

 * apr_file_remove() a file still in use (opened elsewhere), the inode

 * remains until the last fd is closed, whereas any file created with

 * the same name/path will use a new inode.

 *

 * On windows and OS/2 ("\SHAREMEM\..." tree), apr_file_remove() marks

 * the files for deletion until the last HANDLE is closed, meanwhile the

 * same file/path can't be opened/recreated.

 * Thus on graceful restart (the only restart mode with mpm_winnt), the

 * old file may still exist until all the children stop, while we ought

 * to create a new one for our new clear SHM.  Therefore, we would only

 * be able to reuse (attach) the old SHM, preventing some changes to

 * the config file, like the number of balancers/members, since the

 * size checks (to fit the new config) would fail.  Let's avoid this by

 * including the generation number in the SHM filename (obviously not

 * the persisted name!)

 */

#ifndef SLOTMEM_UNLINK_SEMANTIC

#if defined(WIN32) || defined(OS2)

#define SLOTMEM_UNLINK_SEMANTIC 0

#else

#define SLOTMEM_UNLINK_SEMANTIC 1

#endif

#endif



/*

 * Persist the slotmem in a file

 * slotmem name and file name.
@@ -113,18 +88,11 @@ static int slotmem_filenames(apr_pool_t *pool, 


    if (slotname && *slotname && strcasecmp(slotname, "none") != 0) {

        if (slotname[0] != '/') {

#if !SLOTMEM_UNLINK_SEMANTIC

            /* Each generation needs its own file name. */

            int generation = 0;

            ap_mpm_query(AP_MPMQ_GENERATION, &generation);

            fname = apr_psprintf(pool, "%s%s_%x%s", DEFAULT_SLOTMEM_PREFIX,

                                 slotname, generation, DEFAULT_SLOTMEM_SUFFIX);

#else

            /* Reuse the same file name for each generation. */

            fname = apr_pstrcat(pool, DEFAULT_SLOTMEM_PREFIX,

                                slotname, DEFAULT_SLOTMEM_SUFFIX,

                                NULL);

#endif

            fname = ap_runtime_dir_relative(pool, fname);

        }

        else {
@@ -136,7 +104,6 @@ static int slotmem_filenames(apr_pool_t *pool, 


        if (persistname) {

            /* Persisted file names are immutable... */

#if !SLOTMEM_UNLINK_SEMANTIC

            if (slotname[0] != '/') {

                pname = apr_pstrcat(pool, DEFAULT_SLOTMEM_PREFIX,

                                    slotname, DEFAULT_SLOTMEM_SUFFIX,
@@ -144,13 +111,13 @@ static int slotmem_filenames(apr_pool_t *pool, 
                                    NULL);

                pname = ap_runtime_dir_relative(pool, pname);

            }

            else

#endif

            pname = apr_pstrcat(pool, fname,

            else {

                pname = apr_pstrcat(pool, slotname,

                                    DEFAULT_SLOTMEM_PERSIST_SUFFIX,

                                    NULL);

            }

        }

    }



    *filename = fname;

    if (persistname) {