Commit 07a48369 authored by Graham Leggett's avatar Graham Leggett
Browse files

mod_slotmem_shm: Fix slots/SHM files names on restart for systems that 

can't create new (clear) slots while previous children gracefully stopping
still use the old ones (e.g. Windows, OS2). PR 58024.

Submitted by: ylavic
Reviewed by: jim, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1705499 13f79535-47bb-0310-9956-ffa450edef68
parent 8d0af4d2

CHANGES

+6 −0
Original line number Diff line number Diff line
@@ -2,6 +2,12 @@ 


Changes with Apache 2.4.17



  *) mod_slotmem_shm: Fix slots/SHM files names on restart for systems that

     can't create new (clear) slots while previous children gracefully stopping

     still use the old ones (e.g. Windows, OS2). mod_proxy_balancer failed to

     restart whenever the number of configured balancers/members changed during

     restart.  PR 58024.  [Yann Ylavic]



  *) core/util_script: make REDIRECT_URL a full URL.  PR 57785. [Nick Kew]



  *) MPMs: Support SO_REUSEPORT to create multiple duplicated listener

STATUS

+0 −15
Original line number Diff line number Diff line
@@ -109,21 +109,6 @@ RELEASE SHOWSTOPPERS: 
PATCHES ACCEPTED TO BACKPORT FROM TRUNK:

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



  *) mod_slotmem_shm: Fix slots/SHM files names on restart for systems that

     can't create new (clear) slots while previous children gracefully stopping

     still use the old ones (e.g. Windows, OS2). PR 58024.

     trunk patch: http://svn.apache.org/r1702450

                  http://svn.apache.org/r1702473

                  http://svn.apache.org/r1702501

                  http://svn.apache.org/r1702955

                  http://svn.apache.org/r1703149

                  http://svn.apache.org/r1703157

                  http://svn.apache.org/r1703169

                  http://svn.apache.org/r1703200

     2.4.x patch: trunk works (module CHANGES)

     merge patch: http://people.apache.org/~ylavic/httpd-2.4.x-mod_slotmem_shm-generation.patch

     +1: ylavic, jim, minfrin



 



PATCHES PROPOSED TO BACKPORT FROM TRUNK:

modules/slotmem/mod_slotmem_shm.c

+89 −59
Original line number Diff line number Diff line
@@ -25,23 +25,7 @@ 


#include "httpd.h"

#include "http_main.h"

#ifdef AP_NEED_SET_MUTEX_PERMS

#include "unixd.h"

#endif



#if APR_HAVE_UNISTD_H

#include <unistd.h>         /* for getpid() */

#endif



#if HAVE_SYS_SEM_H

#include <sys/shm.h>

#if !defined(SHM_R)

#define SHM_R 0400

#endif

#if !defined(SHM_W)

#define SHM_W 0200

#endif

#endif

#include "ap_mpm.h" /* for ap_mpm_query() */



#define AP_SLOTMEM_IS_PREGRAB(t)    (t->desc.type & AP_SLOTMEM_TYPE_PREGRAB)

#define AP_SLOTMEM_IS_PERSIST(t)    (t->desc.type & AP_SLOTMEM_TYPE_PERSIST)
@@ -58,7 +42,8 @@ typedef struct { 
#define AP_UNSIGNEDINT_OFFSET (APR_ALIGN_DEFAULT(sizeof(unsigned int)))



struct ap_slotmem_instance_t {

    char                 *name;       /* per segment name */

    char                 *name;       /* file based SHM path/name */

    char                 *pname;      /* persisted file path/name */

    int                  fbased;      /* filebased? */

    void                 *shm;        /* ptr to memory segment (apr_shm_t *) */

    void                 *base;       /* data set start */
@@ -86,6 +71,31 @@ 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.
@@ -94,29 +104,59 @@ static apr_pool_t *gpool = NULL; 
 * /abs_name : $abs_name

 *

 */



static const char *slotmem_filename(apr_pool_t *pool, const char *slotmemname,

                                    int persist)

static int slotmem_filenames(apr_pool_t *pool,

                             const char *slotname,

                             const char **filename,

                             const char **persistname)

{

    const char *fname;

    if (!slotmemname || strcasecmp(slotmemname, "none") == 0) {

        return NULL;

    }

    else if (slotmemname[0] != '/') {

        const char *filenm = apr_pstrcat(pool, DEFAULT_SLOTMEM_PREFIX,

                                         slotmemname, DEFAULT_SLOTMEM_SUFFIX,

    const char *fname = NULL, *pname = NULL;



    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);

        fname = ap_runtime_dir_relative(pool, filenm);

#endif

            fname = ap_runtime_dir_relative(pool, fname);

        }

        else {

        fname = slotmemname;

            /* Don't mangle the file name if given an absolute path, it's

             * up to the caller to provide a unique name when necessary.

             */

            fname = slotname;

        }



    if (persist) {

        return apr_pstrcat(pool, fname, DEFAULT_SLOTMEM_PERSIST_SUFFIX,

        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,

                                    DEFAULT_SLOTMEM_PERSIST_SUFFIX,

                                    NULL);

                pname = ap_runtime_dir_relative(pool, pname);

            }

            else

#endif

            pname = apr_pstrcat(pool, fname,

                                DEFAULT_SLOTMEM_PERSIST_SUFFIX,

                                NULL);

        }

    return fname;

    }



    *filename = fname;

    if (persistname) {

        *persistname = pname;

    }

    return (fname != NULL);

}



static void slotmem_clearinuse(ap_slotmem_instance_t *slot)
@@ -143,10 +183,8 @@ static void store_slotmem(ap_slotmem_instance_t *slotmem) 
    apr_file_t *fp;

    apr_status_t rv;

    apr_size_t nbytes;

    const char *storename;

    unsigned char digest[APR_MD5_DIGESTSIZE];



    storename = slotmem_filename(slotmem->gpool, slotmem->name, 1);

    const char *storename = slotmem->pname;



    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02334)

                 "storing %s", storename);
@@ -179,18 +217,15 @@ static void store_slotmem(ap_slotmem_instance_t *slotmem) 
    }

}



static apr_status_t restore_slotmem(void *ptr, const char *name, apr_size_t size,

                                    apr_pool_t *pool)

static apr_status_t restore_slotmem(void *ptr, const char *storename,

                                    apr_size_t size, apr_pool_t *pool)

{

    const char *storename;

    apr_file_t *fp;

    apr_size_t nbytes = size;

    apr_status_t rv = APR_SUCCESS;

    unsigned char digest[APR_MD5_DIGESTSIZE];

    unsigned char digest2[APR_MD5_DIGESTSIZE];



    storename = slotmem_filename(pool, name, 1);



    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02335)

                 "restoring %s", storename);
@@ -246,15 +281,11 @@ static apr_status_t cleanup_slotmem(void *param) 
            if (AP_SLOTMEM_IS_PERSIST(next)) {

                store_slotmem(next);

            }

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

            if (next->fbased) {

                const char *name;

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

                name = slotmem_filename(next->gpool, next->name, 0);

                if (name) {

                    apr_file_remove(name, next->gpool);

                }

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

            }

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

            next = next->next;

        }

    }
@@ -295,25 +326,24 @@ static apr_status_t slotmem_create(ap_slotmem_instance_t **new, 
                                   unsigned int item_num,

                                   ap_slotmem_type_t type, apr_pool_t *pool)

{

/*    void *slotmem = NULL; */

    int fbased = 1;

    int restored = 0;

    char *ptr;

    sharedslotdesc_t desc;

    ap_slotmem_instance_t *res;

    ap_slotmem_instance_t *next = globallistmem;

    const char *fname;

    const char *fname, *pname = NULL;

    apr_shm_t *shm;

    apr_size_t basesize = (item_size * item_num);

    apr_size_t size = AP_SLOTMEM_OFFSET + AP_UNSIGNEDINT_OFFSET +

                      (item_num * sizeof(char)) + basesize;

    int persist = (type & AP_SLOTMEM_TYPE_PERSIST) != 0;

    apr_status_t rv;



    if (gpool == NULL) {

        return APR_ENOSHMAVAIL;

    }

    fname = slotmem_filename(pool, name, 0);

    if (fname) {

    if (slotmem_filenames(pool, name, &fname, persist ? &pname : NULL)) {

        /* first try to attach to existing slotmem */

        if (next) {

            for (;;) {
@@ -399,8 +429,8 @@ static apr_status_t slotmem_create(ap_slotmem_instance_t **new, 
         * TODO: Error check the below... What error makes

         * sense if the restore fails? Any?

         */

        if (type & AP_SLOTMEM_TYPE_PERSIST) {

            rv = restore_slotmem(ptr, fname, dsize, pool);

        if (persist) {

            rv = restore_slotmem(ptr, pname, dsize, pool);

            if (rv == APR_SUCCESS) {

                restored = 1;

            }
@@ -417,6 +447,7 @@ static apr_status_t slotmem_create(ap_slotmem_instance_t **new, 
    res = (ap_slotmem_instance_t *) apr_pcalloc(gpool,

                                                sizeof(ap_slotmem_instance_t));

    res->name = apr_pstrdup(gpool, fname);

    res->pname = apr_pstrdup(gpool, pname);

    res->fbased = fbased;

    res->shm = shm;

    res->num_free = (unsigned int *)ptr;
@@ -457,8 +488,7 @@ static apr_status_t slotmem_attach(ap_slotmem_instance_t **new, 
    if (gpool == NULL) {

        return APR_ENOSHMAVAIL;

    }

    fname = slotmem_filename(pool, name, 0);

    if (!fname) {

    if (!slotmem_filenames(pool, name, &fname, NULL)) {

        return APR_ENOSHMAVAIL;

    }

server/mpm/winnt/mpm_winnt.c

+18 −2
Original line number Diff line number Diff line
@@ -360,6 +360,13 @@ static int send_handles_to_child(apr_pool_t *p, 
    HANDLE hScore;

    apr_size_t BytesWritten;



    if ((rv = apr_file_write_full(child_in, &my_generation,

                                  sizeof(my_generation), NULL))

            != APR_SUCCESS) {

        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(02964)

                     "Parent: Unable to send its generation to the child");

        return -1;

    }

    if (!DuplicateHandle(hCurrentProcess, child_ready_event, hProcess, &hDup,

        EVENT_MODIFY_STATE | SYNCHRONIZE, FALSE, 0)) {

        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf, APLOGNO(00392)
@@ -1037,6 +1044,7 @@ static void winnt_rewrite_args(process_rec *process) 
    {

        HANDLE filehand;

        HANDLE hproc = GetCurrentProcess();

        DWORD BytesRead;



        /* This is the child */

        my_pid = GetCurrentProcessId();
@@ -1074,6 +1082,16 @@ static void winnt_rewrite_args(process_rec *process) 
         * already

         */



        /* Read this child's generation number as soon as now,

         * so that further hooks can query it.

         */

        if (!ReadFile(pipe, &my_generation, sizeof(my_generation),

                      &BytesRead, (LPOVERLAPPED) NULL)

                || (BytesRead != sizeof(my_generation))) {

            ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), NULL, APLOGNO(02965)

                         "Child: Unable to retrieve my generation from the parent");

            exit(APEXIT_CHILDINIT);

        }



        /* The parent is responsible for providing the

         * COMPLETE ARGUMENTS REQUIRED to the child.
@@ -1665,8 +1683,6 @@ static void winnt_child_init(apr_pool_t *pchild, struct server_rec *s) 


        /* Done reading from the parent, close that channel */

        CloseHandle(pipe);



        my_generation = ap_scoreboard_image->global->running_generation;

    }

    else {

        /* Single process mode - this lock doesn't even need to exist */