mod_slotmem_shm.c revision 4736b790b4c02a55e20019eb3c733d0b5c3f86c8
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* Memory handler for a shared memory divided in slot.
* This one uses shared memory.
*/
#include "ap_slotmem.h"
#include "httpd.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
#define AP_SLOTMEM_IS_PREGRAB(t) (t->desc.type & AP_SLOTMEM_TYPE_PREGRAB)
/* The description of the slots to reuse the slotmem */
typedef struct {
apr_size_t size; /* size of each memory slot */
unsigned int num; /* number of mem slots */
ap_slotmem_type_t type; /* type-specific flags */
} sharedslotdesc_t;
struct ap_slotmem_instance_t {
char *name; /* per segment name */
void *shm; /* ptr to memory segment (apr_shm_t *) */
void *base; /* data set start */
apr_pool_t *gpool; /* per segment global pool */
char *inuse; /* in-use flag table*/
sharedslotdesc_t desc; /* per slot desc */
struct ap_slotmem_instance_t *next; /* location of next allocated segment */
};
/*
* Memory layout:
* sharedslotdesc_t | slots | isuse array
*/
/* global pool and list of slotmem we are handling */
static struct ap_slotmem_instance_t *globallistmem = NULL;
static apr_pool_t *gpool = NULL;
/* apr:shmem/unix/shm.c */
static apr_status_t unixd_set_shm_perms(const char *fname)
{
#ifdef AP_NEED_SET_MUTEX_PERMS
#if APR_USE_SHMEM_SHMGET || APR_USE_SHMEM_SHMGET_ANON
struct shmid_ds shmbuf;
key_t shmkey;
int shmid;
shmkey = ftok(fname, 1);
if (shmkey == (key_t)-1) {
return errno;
}
if ((shmid = shmget(shmkey, 0, SHM_R | SHM_W)) == -1) {
return errno;
}
#if MODULE_MAGIC_NUMBER_MAJOR > 20081212
shmbuf.shm_perm.uid = ap_unixd_config.user_id;
shmbuf.shm_perm.gid = ap_unixd_config.group_id;
#else
shmbuf.shm_perm.uid = unixd_config.user_id;
shmbuf.shm_perm.gid = unixd_config.group_id;
#endif
shmbuf.shm_perm.mode = 0600;
if (shmctl(shmid, IPC_SET, &shmbuf) == -1) {
return errno;
}
return APR_SUCCESS;
#else
return APR_ENOTIMPL;
#endif
#else
return APR_ENOTIMPL;
#endif
}
/*
* Persiste the slotmem in a file
* slotmem name and file name.
* anonymous : $server_root/logs/anonymous.slotmem
* :module.c : $server_root/logs/module.c.slotmem
* abs_name : $abs_name.slotmem
*
*/
static const char *store_filename(apr_pool_t *pool, const char *slotmemname)
{
const char *storename;
const char *fname;
if (strcmp(slotmemname, "anonymous") == 0)
fname = ap_server_root_relative(pool, "logs/anonymous");
else if (slotmemname[0] == ':') {
const char *tmpname;
tmpname = apr_pstrcat(pool, "logs/", &slotmemname[1], NULL);
fname = ap_server_root_relative(pool, tmpname);
}
else {
fname = slotmemname;
}
storename = apr_pstrcat(pool, fname, ".slotmem", NULL);
return storename;
}
static void store_slotmem(ap_slotmem_instance_t *slotmem)
{
apr_file_t *fp;
apr_status_t rv;
apr_size_t nbytes;
const char *storename;
storename = store_filename(slotmem->gpool, slotmem->name);
rv = apr_file_open(&fp, storename, APR_CREATE | APR_READ | APR_WRITE,
APR_OS_DEFAULT, slotmem->gpool);
if (APR_STATUS_IS_EEXIST(rv)) {
apr_file_remove(storename, slotmem->gpool);
rv = apr_file_open(&fp, storename, APR_CREATE | APR_READ | APR_WRITE,
APR_OS_DEFAULT, slotmem->gpool);
}
if (rv != APR_SUCCESS) {
return;
}
nbytes = (slotmem->desc.size * slotmem->desc.num) +
(slotmem->desc.num * sizeof(char));
apr_file_write(fp, slotmem->base, &nbytes);
apr_file_close(fp);
}
static void restore_slotmem(void *ptr, const char *name, apr_size_t size,
apr_pool_t *pool)
{
const char *storename;
apr_file_t *fp;
apr_size_t nbytes = size;
apr_status_t rv;
storename = store_filename(pool, name);
rv = apr_file_open(&fp, storename, APR_READ | APR_WRITE, APR_OS_DEFAULT,
pool);
if (rv == APR_SUCCESS) {
apr_finfo_t fi;
if (apr_file_info_get(&fi, APR_FINFO_SIZE, fp) == APR_SUCCESS) {
if (fi.size == nbytes) {
apr_file_read(fp, ptr, &nbytes);
}
else {
apr_file_close(fp);
apr_file_remove(storename, pool);
return;
}
}
apr_file_close(fp);
}
}
static apr_status_t cleanup_slotmem(void *param)
{
ap_slotmem_instance_t **mem = param;
apr_status_t rv;
apr_pool_t *pool = NULL;
if (*mem) {
ap_slotmem_instance_t *next = *mem;
pool = next->gpool;
while (next) {
store_slotmem(next);
rv = apr_shm_destroy((apr_shm_t *)next->shm);
next = next->next;
}
apr_pool_destroy(pool);
}
return APR_SUCCESS;
}
static apr_status_t slotmem_doall(ap_slotmem_instance_t *mem,
ap_slotmem_callback_fn_t *func,
void *data, apr_pool_t *pool)
{
unsigned int i;
void *ptr;
char *inuse;
if (!mem) {
return APR_ENOSHMAVAIL;
}
ptr = mem->base;
inuse = mem->inuse;
for (i = 0; i < mem->desc.num; i++, inuse++) {
if (!AP_SLOTMEM_IS_PREGRAB(mem) ||
(AP_SLOTMEM_IS_PREGRAB(mem) && *inuse)) {
func((void *) ptr, data, pool);
}
ptr += mem->desc.size;
}
return APR_SUCCESS;
}
static apr_status_t slotmem_create(ap_slotmem_instance_t **new,
const char *name, apr_size_t item_size,
unsigned int item_num,
ap_slotmem_type_t type, apr_pool_t *pool)
{
/* void *slotmem = NULL; */
void *ptr;
sharedslotdesc_t desc;
ap_slotmem_instance_t *res;
ap_slotmem_instance_t *next = globallistmem;
const char *fname;
apr_shm_t *shm;
apr_size_t basesize = (item_size * item_num);
apr_size_t size = sizeof(sharedslotdesc_t) +
(item_num * sizeof(char)) + basesize;
apr_status_t rv;
if (gpool == NULL)
return APR_ENOSHMAVAIL;
if (name) {
if (name[0] == ':') {
fname = name;
}
else {
fname = ap_server_root_relative(pool, name);
}
/* first try to attach to existing slotmem */
while (next) {
if (strcmp(next->name, fname) == 0) {
/* we already have it */
*new = next;
return APR_SUCCESS;
}
next = next->next;
}
}
else {
fname = "anonymous";
}
/* first try to attach to existing shared memory */
if (name && name[0] != ':') {
rv = apr_shm_attach(&shm, fname, gpool);
}
else {
rv = APR_EINVAL;
}
if (rv == APR_SUCCESS) {
/* check size */
if (apr_shm_size_get(shm) != size) {
apr_shm_detach(shm);
return APR_EINVAL;
}
ptr = apr_shm_baseaddr_get(shm);
memcpy(&desc, ptr, sizeof(desc));
if (desc.size != item_size || desc.num != item_num) {
apr_shm_detach(shm);
return APR_EINVAL;
}
ptr = ptr + sizeof(desc);
}
else {
apr_size_t dsize = size - sizeof(sharedslotdesc_t);
if (name && name[0] != ':') {
apr_shm_remove(fname, gpool);
rv = apr_shm_create(&shm, size, fname, gpool);
}
else {
rv = apr_shm_create(&shm, size, NULL, gpool);
}
if (rv != APR_SUCCESS) {
return rv;
}
if (name && name[0] != ':') {
/* Set permissions to shared memory
* so it can be attached by child process
* having different user credentials
*
* See apr:shmem/unix/shm.c
*/
unixd_set_shm_perms(fname);
}
ptr = apr_shm_baseaddr_get(shm);
desc.size = item_size;
desc.num = item_num;
desc.type = type;
memcpy(ptr, &desc, sizeof(desc));
ptr = ptr + sizeof(desc);
memset(ptr, 0, dsize);
if (type & AP_SLOTMEM_TYPE_PERSIST)
restore_slotmem(ptr, fname, dsize, pool);
}
/* For the chained slotmem stuff */
res = (ap_slotmem_instance_t *) apr_pcalloc(gpool,
sizeof(ap_slotmem_instance_t));
res->name = apr_pstrdup(gpool, fname);
res->shm = shm;
res->base = ptr;
res->desc = desc;
res->gpool = gpool;
res->next = NULL;
res->inuse = ptr + basesize;
if (globallistmem == NULL) {
globallistmem = res;
}
else {
next->next = res;
}
*new = res;
return APR_SUCCESS;
}
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; */
void *ptr;
ap_slotmem_instance_t *res;
ap_slotmem_instance_t *next = globallistmem;
sharedslotdesc_t desc;
const char *fname;
apr_shm_t *shm;
apr_status_t rv;
if (gpool == NULL) {
return APR_ENOSHMAVAIL;
}
if (name) {
if (name[0] == ':') {
fname = name;
}
else {
fname = ap_server_root_relative(pool, name);
}
}
else {
return APR_ENOSHMAVAIL;
}
/* first try to attach to existing slotmem */
while (next) {
if (strcmp(next->name, fname) == 0) {
/* we already have it */
*new = next;
*item_size = next->desc.size;
*item_num = next->desc.num;
return APR_SUCCESS;
}
next = next->next;
}
/* first try to attach to existing shared memory */
rv = apr_shm_attach(&shm, fname, gpool);
if (rv != APR_SUCCESS) {
return rv;
}
/* Read the description of the slotmem */
ptr = apr_shm_baseaddr_get(shm);
memcpy(&desc, ptr, sizeof(desc));
ptr = ptr + sizeof(desc);
/* For the chained slotmem stuff */
res = (ap_slotmem_instance_t *) apr_pcalloc(gpool,
sizeof(ap_slotmem_instance_t));
res->name = apr_pstrdup(gpool, fname);
res->shm = shm;
res->base = ptr;
res->desc = desc;
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;
*item_num = desc.num;
return APR_SUCCESS;
}
static apr_status_t slotmem_dptr(ap_slotmem_instance_t *slot,
unsigned int id, void **mem)
{
void *ptr;
if (!slot) {
return APR_ENOSHMAVAIL;
}
if (id < 0 || id >= slot->desc.num) {
return APR_ENOSHMAVAIL;
}
ptr = slot->base + slot->desc.size * id;
if (!ptr) {
return APR_ENOSHMAVAIL;
}
*mem = ptr;
return APR_SUCCESS;
}
static apr_status_t slotmem_get(ap_slotmem_instance_t *slot, unsigned int id,
unsigned char *dest, apr_size_t dest_len)
{
void *ptr;
char *inuse;
apr_status_t ret;
if (!slot) {
return APR_ENOSHMAVAIL;
}
inuse = slot->inuse + id;
if (id >= slot->desc.num || (AP_SLOTMEM_IS_PREGRAB(slot) && !*inuse)) {
return APR_NOTFOUND;
}
ret = slotmem_dptr(slot, id, &ptr);
if (ret != APR_SUCCESS) {
return ret;
}
memcpy(dest, ptr, dest_len); /* bounds check? */
return APR_SUCCESS;
}
static apr_status_t slotmem_put(ap_slotmem_instance_t *slot, unsigned int id,
unsigned char *src, apr_size_t src_len)
{
void *ptr;
char *inuse;
apr_status_t ret;
if (!slot) {
return APR_ENOSHMAVAIL;
}
inuse = slot->inuse + id;
if (id >= slot->desc.num || (AP_SLOTMEM_IS_PREGRAB(slot) && !*inuse)) {
return APR_NOTFOUND;
}
ret = slotmem_dptr(slot, id, &ptr);
if (ret != APR_SUCCESS) {
return ret;
}
memcpy(ptr, src, src_len); /* bounds check? */
return APR_SUCCESS;
}
static unsigned int slotmem_num_slots(ap_slotmem_instance_t *slot)
{
return slot->desc.num;
}
static apr_size_t slotmem_slot_size(ap_slotmem_instance_t *slot)
{
return slot->desc.size;
}
/*
* XXXX: if !AP_SLOTMEM_IS_PREGRAB, then still worry about
* inuse for grab and return?
*/
static apr_status_t slotmem_grab(ap_slotmem_instance_t *slot, unsigned int *id)
{
unsigned int i;
char *inuse;
if (!slot) {
return APR_ENOSHMAVAIL;
}
inuse = slot->inuse;
for (i = 0; i < slot->desc.num; i++, inuse++) {
if (!*inuse) {
break;
}
}
if (i >= slot->desc.num) {
return APR_ENOSHMAVAIL;
}
*inuse = 1;
*id = i;
return APR_SUCCESS;
}
static apr_status_t slotmem_release(ap_slotmem_instance_t *slot,
unsigned int id)
{
char *inuse;
if (!slot) {
return APR_ENOSHMAVAIL;
}
inuse = slot->inuse;
if (id >= slot->desc.num || !inuse[id] ) {
return APR_NOTFOUND;
}
inuse[id] = 0;
return APR_SUCCESS;
}
static const ap_slotmem_provider_t storage = {
"sharedmem",
&slotmem_doall,
&slotmem_create,
&slotmem_attach,
&slotmem_dptr,
&slotmem_get,
&slotmem_put,
&slotmem_num_slots,
&slotmem_slot_size,
&slotmem_grab,
&slotmem_release
};
/* make the storage usuable from outside */
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)
{
void *data;
const char *userdata_key = "slotmem_shm_post_config";
apr_pool_userdata_get(&data, userdata_key, s->process->pool);
if (!data) {
apr_pool_userdata_set((const void *)1, userdata_key,
apr_pool_cleanup_null, s->process->pool);
return OK;
}
slotmem_shm_initialize_cleanup(p);
return OK;
}
static int pre_config(apr_pool_t *p, apr_pool_t *plog,
apr_pool_t *ptemp)
{
apr_pool_t *global_pool;
apr_status_t rv;
rv = apr_pool_create(&global_pool, NULL);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
"Fatal error: unable to create global pool for shared slotmem");
return rv;
}
slotmem_shm_initgpool(global_pool);
return OK;
}
static void ap_slotmem_shm_register_hook(apr_pool_t *p)
{
const ap_slotmem_provider_t *storage = slotmem_shm_getstorage();
ap_register_provider(p, AP_SLOTMEM_PROVIDER_GROUP, "shared", "0", storage);
ap_hook_post_config(post_config, NULL, NULL, APR_HOOK_LAST);
ap_hook_pre_config(pre_config, NULL, NULL, APR_HOOK_MIDDLE);
}
module AP_MODULE_DECLARE_DATA slotmem_shm_module = {
STANDARD20_MODULE_STUFF,
NULL, /* create per-directory config structure */
NULL, /* merge per-directory config structures */
NULL, /* create per-server config structure */
NULL, /* merge per-server config structures */
NULL, /* command apr_table_t */
ap_slotmem_shm_register_hook /* register hooks */
};