mod_socache_dbm.c revision 027f7b141f164258b254c38319d06452b25d7660
/* 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.
*/
#include "httpd.h"
#include "http_log.h"
#include "http_request.h"
#include "http_protocol.h"
#include "http_config.h"
#include "mpm_common.h"
#include "apr.h"
#include "apr_strings.h"
#include "apr_time.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include "apr_dbm.h"
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "ap_socache.h"
#if AP_NEED_SET_MUTEX_PERMS
#include "unixd.h"
#endif
/* Use of the context structure must be thread-safe after the initial
* create/init; callers must hold the mutex. */
struct ap_socache_instance_t {
const char *data_file;
/* Pool must only be used with the mutex held. */
apr_pool_t *pool;
apr_time_t last_expiry;
apr_interval_time_t expiry_interval;
};
/**
* Support for DBM library
*/
#define DBM_FILE_MODE ( APR_UREAD | APR_UWRITE | APR_GREAD | APR_WREAD )
#define DEFAULT_DBM_PREFIX DEFAULT_REL_RUNTIMEDIR "/socache-dbm-"
/* ### this should use apr_dbm_usednames. */
#if !defined(DBM_FILE_SUFFIX_DIR) && !defined(DBM_FILE_SUFFIX_PAG)
#if defined(DBM_SUFFIX)
#define DBM_FILE_SUFFIX_DIR DBM_SUFFIX
#define DBM_FILE_SUFFIX_PAG DBM_SUFFIX
#elif defined(__FreeBSD__) || (defined(DB_LOCK) && defined(DB_SHMEM))
#define DBM_FILE_SUFFIX_DIR ".db"
#define DBM_FILE_SUFFIX_PAG ".db"
#else
#define DBM_FILE_SUFFIX_DIR ".dir"
#define DBM_FILE_SUFFIX_PAG ".pag"
#endif
#endif
static void socache_dbm_expire(ap_socache_instance_t *ctx, server_rec *s);
static apr_status_t socache_dbm_remove(ap_socache_instance_t *ctx,
server_rec *s, const unsigned char *id,
unsigned int idlen, apr_pool_t *p);
static const char *socache_dbm_create(ap_socache_instance_t **context,
const char *arg,
apr_pool_t *tmp, apr_pool_t *p)
{
ap_socache_instance_t *ctx;
*context = ctx = apr_pcalloc(p, sizeof *ctx);
if (arg && *arg) {
ctx->data_file = ap_server_root_relative(p, arg);
if (!ctx->data_file) {
return apr_psprintf(tmp, "Invalid cache file path %s", arg);
}
}
apr_pool_create(&ctx->pool, p);
return NULL;
}
static apr_status_t socache_dbm_init(ap_socache_instance_t *ctx,
const char *namespace,
const struct ap_socache_hints *hints,
server_rec *s, apr_pool_t *p)
{
apr_dbm_t *dbm;
apr_status_t rv;
/* for the DBM we need the data file */
if (ctx->data_file == NULL) {
const char *path = apr_pstrcat(p, DEFAULT_DBM_PREFIX, namespace,
NULL);
ctx->data_file = ap_server_root_relative(p, path);
if (ctx->data_file == NULL) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
"could not use default path '%s' for DBM socache",
path);
return APR_EINVAL;
}
}
/* open it once to create it and to make sure it _can_ be created */
apr_pool_clear(ctx->pool);
if ((rv = apr_dbm_open(&dbm, ctx->data_file,
APR_DBM_RWCREATE, DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot create socache DBM file `%s'",
ctx->data_file);
return rv;
}
apr_dbm_close(dbm);
ctx->expiry_interval = (hints && hints->expiry_interval
? hints->expiry_interval : apr_time_from_sec(30));
#if AP_NEED_SET_MUTEX_PERMS
/*
* We have to make sure the Apache child processes have access to
* the DBM file. But because there are brain-dead platforms where we
* cannot exactly determine the suffixes we try all possibilities.
*/
if (geteuid() == 0 /* is superuser */) {
chown(ctx->data_file, ap_unixd_config.user_id, -1 /* no gid change */);
if (chown(apr_pstrcat(p, ctx->data_file, DBM_FILE_SUFFIX_DIR, NULL),
ap_unixd_config.user_id, -1) == -1) {
if (chown(apr_pstrcat(p, ctx->data_file, ".db", NULL),
ap_unixd_config.user_id, -1) == -1)
chown(apr_pstrcat(p, ctx->data_file, ".dir", NULL),
ap_unixd_config.user_id, -1);
}
if (chown(apr_pstrcat(p, ctx->data_file, DBM_FILE_SUFFIX_PAG, NULL),
ap_unixd_config.user_id, -1) == -1) {
if (chown(apr_pstrcat(p, ctx->data_file, ".db", NULL),
ap_unixd_config.user_id, -1) == -1)
chown(apr_pstrcat(p, ctx->data_file, ".pag", NULL),
ap_unixd_config.user_id, -1);
}
}
#endif
socache_dbm_expire(ctx, s);
return APR_SUCCESS;
}
static void socache_dbm_destroy(ap_socache_instance_t *ctx, server_rec *s)
{
/* the correct way */
unlink(apr_pstrcat(ctx->pool, ctx->data_file, DBM_FILE_SUFFIX_DIR, NULL));
unlink(apr_pstrcat(ctx->pool, ctx->data_file, DBM_FILE_SUFFIX_PAG, NULL));
/* the additional ways to be sure */
unlink(apr_pstrcat(ctx->pool, ctx->data_file, ".dir", NULL));
unlink(apr_pstrcat(ctx->pool, ctx->data_file, ".pag", NULL));
unlink(apr_pstrcat(ctx->pool, ctx->data_file, ".db", NULL));
unlink(ctx->data_file);
return;
}
static apr_status_t socache_dbm_store(ap_socache_instance_t *ctx,
server_rec *s, const unsigned char *id,
unsigned int idlen, apr_time_t expiry,
unsigned char *ucaData,
unsigned int nData, apr_pool_t *pool)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_datum_t dbmval;
apr_status_t rv;
/* be careful: do not try to store too much bytes in a DBM file! */
#ifdef PAIRMAX
if ((idlen + nData) >= PAIRMAX) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
"data size too large for DBM socache: %d >= %d",
(idlen + nData), PAIRMAX);
return APR_ENOSPC;
}
#else
if ((idlen + nData) >= 950 /* at least less than approx. 1KB */) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
"data size too large for DBM socache: %d >= %d",
(idlen + nData), 950);
return APR_ENOSPC;
}
#endif
/* create DBM key */
dbmkey.dptr = (char *)id;
dbmkey.dsize = idlen;
/* create DBM value */
dbmval.dsize = sizeof(apr_time_t) + nData;
dbmval.dptr = (char *)malloc(dbmval.dsize);
if (dbmval.dptr == NULL) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
"malloc error creating DBM value");
return APR_ENOMEM;
}
memcpy((char *)dbmval.dptr, &expiry, sizeof(apr_time_t));
memcpy((char *)dbmval.dptr+sizeof(apr_time_t), ucaData, nData);
/* and store it to the DBM file */
apr_pool_clear(ctx->pool);
if ((rv = apr_dbm_open(&dbm, ctx->data_file,
APR_DBM_RWCREATE, DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot open socache DBM file `%s' for writing "
"(store)",
ctx->data_file);
free(dbmval.dptr);
return rv;
}
if ((rv = apr_dbm_store(dbm, dbmkey, dbmval)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot store socache object to DBM file `%s'",
ctx->data_file);
apr_dbm_close(dbm);
free(dbmval.dptr);
return rv;
}
apr_dbm_close(dbm);
/* free temporary buffers */
free(dbmval.dptr);
/* allow the regular expiring to occur */
socache_dbm_expire(ctx, s);
return APR_SUCCESS;
}
static apr_status_t socache_dbm_retrieve(ap_socache_instance_t *ctx, server_rec *s,
const unsigned char *id, unsigned int idlen,
unsigned char *dest, unsigned int *destlen,
apr_pool_t *p)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_datum_t dbmval;
unsigned int nData;
apr_time_t expiry;
apr_time_t now;
apr_status_t rc;
/* allow the regular expiring to occur */
socache_dbm_expire(ctx, s);
/* create DBM key and values */
dbmkey.dptr = (char *)id;
dbmkey.dsize = idlen;
/* and fetch it from the DBM file
* XXX: Should we open the dbm against r->pool so the cleanup will
* do the apr_dbm_close? This would make the code a bit cleaner.
*/
apr_pool_clear(ctx->pool);
if ((rc = apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rc, s,
"Cannot open socache DBM file `%s' for reading "
"(fetch)",
ctx->data_file);
return rc;
}
rc = apr_dbm_fetch(dbm, dbmkey, &dbmval);
if (rc != APR_SUCCESS) {
apr_dbm_close(dbm);
return APR_NOTFOUND;
}
if (dbmval.dptr == NULL || dbmval.dsize <= sizeof(apr_time_t)) {
apr_dbm_close(dbm);
return APR_EGENERAL;
}
/* parse resulting data */
nData = dbmval.dsize-sizeof(apr_time_t);
if (nData > *destlen) {
apr_dbm_close(dbm);
return APR_ENOSPC;
}
*destlen = nData;
memcpy(&expiry, dbmval.dptr, sizeof(apr_time_t));
memcpy(dest, (char *)dbmval.dptr + sizeof(apr_time_t), nData);
apr_dbm_close(dbm);
/* make sure the stuff is still not expired */
now = apr_time_now();
if (expiry <= now) {
socache_dbm_remove(ctx, s, id, idlen, p);
return APR_NOTFOUND;
}
return APR_SUCCESS;
}
static apr_status_t socache_dbm_remove(ap_socache_instance_t *ctx,
server_rec *s, const unsigned char *id,
unsigned int idlen, apr_pool_t *p)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_status_t rv;
/* create DBM key and values */
dbmkey.dptr = (char *)id;
dbmkey.dsize = idlen;
/* and delete it from the DBM file */
apr_pool_clear(ctx->pool);
if ((rv = apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot open socache DBM file `%s' for writing "
"(delete)",
ctx->data_file);
return rv;
}
apr_dbm_delete(dbm, dbmkey);
apr_dbm_close(dbm);
return APR_SUCCESS;
}
static void socache_dbm_expire(ap_socache_instance_t *ctx, server_rec *s)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_datum_t dbmval;
apr_time_t expiry;
int elts = 0;
int deleted = 0;
int expired;
apr_datum_t *keylist;
int keyidx;
int i;
apr_time_t now;
apr_status_t rv;
/*
* make sure the expiration for still not-accessed
* socache entries is done only from time to time
*/
now = apr_time_now();
if (now < ctx->last_expiry + ctx->expiry_interval) {
return;
}
ctx->last_expiry = now;
/*
* Here we have to be very carefully: Not all DBM libraries are
* smart enough to allow one to iterate over the elements and at the
* same time delete expired ones. Some of them get totally crazy
* while others have no problems. So we have to do it the slower but
* more safe way: we first iterate over all elements and remember
* those which have to be expired. Then in a second pass we delete
* all those expired elements. Additionally we reopen the DBM file
* to be really safe in state.
*/
#define KEYMAX 1024
for (;;) {
/* allocate the key array in a memory sub pool */
apr_pool_clear(ctx->pool);
if ((keylist = apr_palloc(ctx->pool, sizeof(dbmkey)*KEYMAX)) == NULL) {
break;
}
/* pass 1: scan DBM database */
keyidx = 0;
if ((rv = apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot open socache DBM file `%s' for "
"scanning",
ctx->data_file);
break;
}
apr_dbm_firstkey(dbm, &dbmkey);
while (dbmkey.dptr != NULL) {
elts++;
expired = FALSE;
apr_dbm_fetch(dbm, dbmkey, &dbmval);
if (dbmval.dsize <= sizeof(apr_time_t) || dbmval.dptr == NULL)
expired = TRUE;
else {
memcpy(&expiry, dbmval.dptr, sizeof(apr_time_t));
if (expiry <= now)
expired = TRUE;
}
if (expired) {
if ((keylist[keyidx].dptr = apr_pmemdup(ctx->pool, dbmkey.dptr, dbmkey.dsize)) != NULL) {
keylist[keyidx].dsize = dbmkey.dsize;
keyidx++;
if (keyidx == KEYMAX)
break;
}
}
apr_dbm_nextkey(dbm, &dbmkey);
}
apr_dbm_close(dbm);
/* pass 2: delete expired elements */
if (apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot re-open socache DBM file `%s' for "
"expiring",
ctx->data_file);
break;
}
for (i = 0; i < keyidx; i++) {
apr_dbm_delete(dbm, keylist[i]);
deleted++;
}
apr_dbm_close(dbm);
if (keyidx < KEYMAX)
break;
}
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
"DBM socache expiry: "
"old: %d, new: %d, removed: %d",
elts, elts-deleted, deleted);
}
static void socache_dbm_status(ap_socache_instance_t *ctx, request_rec *r,
int flags)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_datum_t dbmval;
int elts;
long size;
int avg;
apr_status_t rv;
elts = 0;
size = 0;
apr_pool_clear(ctx->pool);
if ((rv = apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
"Cannot open socache DBM file `%s' for status "
"retrival",
ctx->data_file);
return;
}
/*
* XXX - Check the return value of apr_dbm_firstkey, apr_dbm_fetch - TBD
*/
apr_dbm_firstkey(dbm, &dbmkey);
for ( ; dbmkey.dptr != NULL; apr_dbm_nextkey(dbm, &dbmkey)) {
apr_dbm_fetch(dbm, dbmkey, &dbmval);
if (dbmval.dptr == NULL)
continue;
elts += 1;
size += dbmval.dsize;
}
apr_dbm_close(dbm);
if (size > 0 && elts > 0)
avg = (int)(size / (long)elts);
else
avg = 0;
ap_rprintf(r, "cache type: <b>DBM</b>, maximum size: <b>unlimited</b><br>");
ap_rprintf(r, "current entries: <b>%d</b>, current size: <b>%ld</b> bytes<br>", elts, size);
ap_rprintf(r, "average entry size: <b>%d</b> bytes<br>", avg);
return;
}
static apr_status_t socache_dbm_iterate(ap_socache_instance_t *ctx,
server_rec *s, void *userctx,
ap_socache_iterator_t *iterator,
apr_pool_t *pool)
{
apr_dbm_t *dbm;
apr_datum_t dbmkey;
apr_datum_t dbmval;
apr_time_t expiry;
int expired;
apr_time_t now;
apr_status_t rv;
/*
* make sure the expired records are omitted
*/
now = apr_time_now();
if ((rv = apr_dbm_open(&dbm, ctx->data_file, APR_DBM_RWCREATE,
DBM_FILE_MODE, ctx->pool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Cannot open socache DBM file `%s' for "
"iterating", ctx->data_file);
return rv;
}
rv = apr_dbm_firstkey(dbm, &dbmkey);
while (rv == APR_SUCCESS && dbmkey.dptr != NULL) {
expired = FALSE;
apr_dbm_fetch(dbm, dbmkey, &dbmval);
if (dbmval.dsize <= sizeof(apr_time_t) || dbmval.dptr == NULL)
expired = TRUE;
else {
memcpy(&expiry, dbmval.dptr, sizeof(apr_time_t));
if (expiry <= now)
expired = TRUE;
}
if (!expired) {
rv = iterator(ctx, s, userctx,
(unsigned char *)dbmkey.dptr, dbmkey.dsize,
(unsigned char *)dbmval.dptr + sizeof(apr_time_t),
dbmval.dsize - sizeof(apr_time_t), pool);
ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, s,
"dbm `%s' entry iterated", ctx->data_file);
if (rv != APR_SUCCESS)
return rv;
}
rv = apr_dbm_nextkey(dbm, &dbmkey);
}
apr_dbm_close(dbm);
if (rv != APR_SUCCESS && rv != APR_EOF) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, s,
"Failure reading first/next socache DBM file `%s' record",
ctx->data_file);
return rv;
}
return APR_SUCCESS;
}
static const ap_socache_provider_t socache_dbm = {
"dbm",
AP_SOCACHE_FLAG_NOTMPSAFE,
socache_dbm_create,
socache_dbm_init,
socache_dbm_destroy,
socache_dbm_store,
socache_dbm_retrieve,
socache_dbm_remove,
socache_dbm_status,
socache_dbm_iterate
};
static void register_hooks(apr_pool_t *p)
{
ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP, "dbm",
AP_SOCACHE_PROVIDER_VERSION,
&socache_dbm);
}
AP_DECLARE_MODULE(socache_dbm) = {
STANDARD20_MODULE_STUFF,
NULL, NULL, NULL, NULL, NULL,
register_hooks
};