Commit 72b0b9dd authored by Yann Ylavic's avatar Yann Ylavic
Browse files

mod_slotmem_shm: follow up to r1831869. 

Don't try to attach SHMs on startup, they might be from a previous crash and
prevent the server to start (on failure to reuse it).

On mpm_winnt though, the pre/post_config() phases are re-run in child process,
and the parent process already created the SMs, so they must be attached there.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1831870 13f79535-47bb-0310-9956-ffa450edef68
parent 0f272dbb

modules/slotmem/mod_slotmem_shm.c

+37 −66
Changes for modules/slotmem/mod_slotmem_shm.c: 37 added lines, 66 removed lines.
Original line number Diff line number Diff line
@@ -238,25 +238,33 @@ static apr_status_t restore_slotmem(void *ptr, const char *storename, 
    return rv;

}



/*

 * Whether the module is called from a MPM that re-enter main() and

 * pre/post_config phases.

 */

static APR_INLINE int is_child_process(void)

{

#ifdef WIN32

    return getenv("AP_PARENT_PID") != NULL;

#else

    return 0;

#endif

}



static apr_status_t cleanup_slotmem(void *param)

{

    ap_slotmem_instance_t **mem = param;

    int is_child = is_child_process();

    ap_slotmem_instance_t *next = globallistmem;



    if (*mem) {

        ap_slotmem_instance_t *next = *mem;

    while (next) {

            if (AP_SLOTMEM_IS_PERSIST(next)) {

        if (!is_child && AP_SLOTMEM_IS_PERSIST(next)) {

            store_slotmem(next);

        }

            apr_shm_destroy((apr_shm_t *)next->shm);

            if (next->fbased) {

        apr_shm_destroy(next->shm);

        apr_shm_remove(next->name, next->gpool);

                apr_file_remove(next->name, next->gpool);

            }

        next = next->next;

    }

    }

    /* apr_pool_destroy(gpool); */



    globallistmem = NULL;

    return APR_SUCCESS;

}
@@ -307,6 +315,7 @@ static apr_status_t slotmem_create(ap_slotmem_instance_t **new, 
    int persist = (type & AP_SLOTMEM_TYPE_PERSIST) != 0;

    apr_status_t rv;



    *new = NULL;

    if (gpool == NULL) {

        return APR_ENOSHMAVAIL;

    }
@@ -339,49 +348,31 @@ static apr_status_t slotmem_create(ap_slotmem_instance_t **new, 
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02300)

                 "create %s: %"APR_SIZE_T_FMT"/%u", fname, item_size,

                 item_num);



    {

        apr_size_t dsize = size - AP_SLOTMEM_OFFSET;



        /* For MPMs that run pre/post_config() phases in both the parent

         * and children processes (e.g. winnt), SHMs created by the

         * parent exist in the children already; attach them.

         */

        if (fbased) {

            if (is_child_process()) {

                rv = apr_shm_attach(&shm, fname, gpool);

            }

            else {

        rv = APR_EINVAL;

    }

    if (rv == APR_SUCCESS) {

        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02598)

                     "apr_shm_attach() succeeded");



        /* check size */

        if (apr_shm_size_get(shm) != size) {

            apr_shm_detach(shm);

            ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(02599)

                         "existing shared memory for %s could not be used (failed size check)",

                         fname);

            return APR_EINVAL;

        }

        ptr = (char *)apr_shm_baseaddr_get(shm);

        memcpy(&desc, ptr, sizeof(desc));

        if (desc.size != item_size || desc.num != item_num) {

            apr_shm_detach(shm);

            ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(02600)

                         "existing shared memory for %s could not be used (failed contents check)",

                         fname);

            return APR_EINVAL;

        }

        ptr += AP_SLOTMEM_OFFSET;

    }

    else {

        apr_size_t dsize = size - AP_SLOTMEM_OFFSET;

        if (fbased) {

            apr_shm_remove(fname, gpool);

                apr_shm_remove(fname, pool);

                rv = apr_shm_create(&shm, size, fname, gpool);

            }

        }

        else {

            rv = apr_shm_create(&shm, size, NULL, gpool);

        }

        ap_log_error(APLOG_MARK, rv == APR_SUCCESS ? APLOG_DEBUG : APLOG_ERR,

                     rv, ap_server_conf, APLOGNO(02611)

                     "create: apr_shm_create(%s) %s",

                     fname ? fname : "",

                     rv == APR_SUCCESS ? "succeeded" : "failed");

                     "create: apr_shm_%s(%s) %s",

                     fbased && is_child_process() ? "attach" : "create",

                     fname, rv == APR_SUCCESS ? "succeeded" : "failed");

        if (rv != APR_SUCCESS) {

            return rv;

        }
@@ -443,7 +434,6 @@ static apr_status_t slotmem_attach(ap_slotmem_instance_t **new, 
                                   const char *name, apr_size_t *item_size,

                                   unsigned int *item_num, apr_pool_t *pool)

{

/*    void *slotmem = NULL; */

    char *ptr;

    ap_slotmem_instance_t *res;

    ap_slotmem_instance_t *next = globallistmem;
@@ -508,12 +498,6 @@ static apr_status_t slotmem_attach(ap_slotmem_instance_t **new, 
    res->gpool = gpool;

    res->inuse = ptr + (desc.size * desc.num);

    res->next = NULL;

    if (globallistmem == NULL) {

        globallistmem = res;

    }

    else {

        next->next = res;

    }



    *new = res;

    *item_size = desc.size;
@@ -726,33 +710,20 @@ static const ap_slotmem_provider_t *slotmem_shm_getstorage(void) 
    return (&storage);

}



/* initialise the global pool */

static void slotmem_shm_initgpool(apr_pool_t *p)

{

    gpool = p;

}



/* Add the pool_clean routine */

static void slotmem_shm_initialize_cleanup(apr_pool_t *p)

{

    apr_pool_cleanup_register(p, &globallistmem, cleanup_slotmem,

                              apr_pool_cleanup_null);

}



/*

 * Make sure the shared memory is cleaned

 */

static int post_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp,

                       server_rec *s)

{

    slotmem_shm_initialize_cleanup(p);

    apr_pool_cleanup_register(p, NULL, cleanup_slotmem, apr_pool_cleanup_null);

    return OK;

}



static int pre_config(apr_pool_t *p, apr_pool_t *plog,

                      apr_pool_t *ptemp)

static int pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp)

{

    slotmem_shm_initgpool(p);

    gpool = p;

    globallistmem = NULL;

    return OK;

}