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

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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
This commit is contained in:
Graham Leggett
2015-09-26 22:55:56 +00:00
parent 462949326b
commit 9ed51f0f1c
4 changed files with 115 additions and 78 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
CHANGES
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@ -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

15
STATUS
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@ -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:

152
modules/slotmem/mod_slotmem_shm.c
View File

@ -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,
NULL);
fname = ap_runtime_dir_relative(pool, filenm);
}
else {
fname = slotmemname;
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);
#endif
fname = ap_runtime_dir_relative(pool, fname);
}
else {
/* 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 (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);
}
}
if (persist) {
return apr_pstrcat(pool, fname, DEFAULT_SLOTMEM_PERSIST_SUFFIX,
NULL);
*filename = fname;
if (persistname) {
*persistname = pname;
}
return fname;
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);
}
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_shm_destroy((apr_shm_t *)next->shm);
if (next->fbased) {
apr_shm_remove(next->name, next->gpool);
apr_file_remove(next->name, next->gpool);
}
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;
}

20
server/mpm/winnt/mpm_winnt.c
View File

@ -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 */