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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:01:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:01:30 +0000
commit6beeb1b708550be0d4a53b272283e17e5e35fe17 (patch)
tree1ce8673d4aaa948e5554000101f46536a1e4cc29 /modules/cache/mod_socache_shmcb.c
parentInitial commit. (diff)
downloadapache2-6beeb1b708550be0d4a53b272283e17e5e35fe17.tar.xz
apache2-6beeb1b708550be0d4a53b272283e17e5e35fe17.zip
Adding upstream version 2.4.57.upstream/2.4.57
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'modules/cache/mod_socache_shmcb.c')
-rw-r--r--modules/cache/mod_socache_shmcb.c1087
1 files changed, 1087 insertions, 0 deletions
diff --git a/modules/cache/mod_socache_shmcb.c b/modules/cache/mod_socache_shmcb.c
new file mode 100644
index 0000000..4727961
--- /dev/null
+++ b/modules/cache/mod_socache_shmcb.c
@@ -0,0 +1,1087 @@
+/* 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 "mod_status.h"
+
+#include "apr.h"
+#include "apr_strings.h"
+#include "apr_time.h"
+#include "apr_shm.h"
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+#include "apr_general.h"
+
+#if APR_HAVE_LIMITS_H
+#include <limits.h>
+#endif
+
+#include "ap_socache.h"
+
+/* XXX Unfortunately, there are still many unsigned ints in use here, so we
+ * XXX cannot allow more than UINT_MAX. Since some of the ints are exposed in
+ * XXX public interfaces, a simple search and replace is not enough.
+ * XXX It should be possible to extend that so that the total cache size can
+ * XXX be APR_SIZE_MAX and only the object size needs to be smaller than
+ * XXX UINT_MAX.
+ */
+#define SHMCB_MAX_SIZE (UINT_MAX<APR_SIZE_MAX ? UINT_MAX : APR_SIZE_MAX)
+
+#define DEFAULT_SHMCB_PREFIX "socache-shmcb-"
+
+#define DEFAULT_SHMCB_SUFFIX ".cache"
+
+#define ALIGNED_HEADER_SIZE APR_ALIGN_DEFAULT(sizeof(SHMCBHeader))
+#define ALIGNED_SUBCACHE_SIZE APR_ALIGN_DEFAULT(sizeof(SHMCBSubcache))
+#define ALIGNED_INDEX_SIZE APR_ALIGN_DEFAULT(sizeof(SHMCBIndex))
+
+/*
+ * Header structure - the start of the shared-mem segment
+ */
+typedef struct {
+ /* Stats for cache operations */
+ unsigned long stat_stores;
+ unsigned long stat_replaced;
+ unsigned long stat_expiries;
+ unsigned long stat_scrolled;
+ unsigned long stat_retrieves_hit;
+ unsigned long stat_retrieves_miss;
+ unsigned long stat_removes_hit;
+ unsigned long stat_removes_miss;
+ /* Number of subcaches */
+ unsigned int subcache_num;
+ /* How many indexes each subcache's queue has */
+ unsigned int index_num;
+ /* How large each subcache is, including the queue and data */
+ unsigned int subcache_size;
+ /* How far into each subcache the data area is (optimisation) */
+ unsigned int subcache_data_offset;
+ /* How large the data area in each subcache is (optimisation) */
+ unsigned int subcache_data_size;
+} SHMCBHeader;
+
+/*
+ * Subcache structure - the start of each subcache, followed by
+ * indexes then data
+ */
+typedef struct {
+ /* The start position and length of the cyclic buffer of indexes */
+ unsigned int idx_pos, idx_used;
+ /* Same for the data area */
+ unsigned int data_pos, data_used;
+} SHMCBSubcache;
+
+/*
+ * Index structure - each subcache has an array of these
+ */
+typedef struct {
+ /* absolute time this entry expires */
+ apr_time_t expires;
+ /* location within the subcache's data area */
+ unsigned int data_pos;
+ /* size (most logic ignores this, we keep it only to minimise memcpy) */
+ unsigned int data_used;
+ /* length of the used data which contains the id */
+ unsigned int id_len;
+ /* Used to mark explicitly-removed socache entries */
+ unsigned char removed;
+} SHMCBIndex;
+
+struct ap_socache_instance_t {
+ apr_pool_t *pool;
+ const char *data_file;
+ apr_size_t shm_size;
+ apr_shm_t *shm;
+ SHMCBHeader *header;
+};
+
+/* The SHM data segment is of fixed size and stores data as follows.
+ *
+ * [ SHMCBHeader | Subcaches ]
+ *
+ * The SHMCBHeader header structure stores metadata concerning the
+ * cache and the contained subcaches.
+ *
+ * Subcaches is a hash table of header->subcache_num SHMCBSubcache
+ * structures. The hash table is indexed by SHMCB_MASK(id). Each
+ * SHMCBSubcache structure has a fixed size (header->subcache_size),
+ * which is determined at creation time, and looks like the following:
+ *
+ * [ SHMCBSubcache | Indexes | Data ]
+ *
+ * Each subcache is prefixed by the SHMCBSubcache structure.
+ *
+ * The subcache's "Data" segment is a single cyclic data buffer, of
+ * total size header->subcache_data_size; data inside is referenced
+ * using byte offsets. The offset marking the beginning of the cyclic
+ * buffer is subcache->data_pos; the buffer's length is
+ * subcache->data_used.
+ *
+ * "Indexes" is an array of header->index_num SHMCBIndex structures,
+ * which is used as a cyclic queue; subcache->idx_pos gives the array
+ * index of the first in use, subcache->idx_used gives the number in
+ * use. Both ->idx_* values have a range of [0, header->index_num)
+ *
+ * Each in-use SHMCBIndex structure represents a single cached object.
+ * The ID and data segment are stored consecutively in the subcache's
+ * cyclic data buffer. The "Data" segment can thus be seen to
+ * look like this, for example
+ *
+ * offset: [ 0 1 2 3 4 5 6 ...
+ * contents:[ ID1 Data1 ID2 Data2 ID3 ...
+ *
+ * where the corresponding indices would look like:
+ *
+ * idx1 = { data_pos = 0, data_used = 3, id_len = 1, ...}
+ * idx2 = { data_pos = 3, data_used = 3, id_len = 1, ...}
+ * ...
+ */
+
+/* This macro takes a pointer to the header and a zero-based index and returns
+ * a pointer to the corresponding subcache. */
+#define SHMCB_SUBCACHE(pHeader, num) \
+ (SHMCBSubcache *)(((unsigned char *)(pHeader)) + \
+ ALIGNED_HEADER_SIZE + \
+ (num) * ((pHeader)->subcache_size))
+
+/* This macro takes a pointer to the header and an id and returns a
+ * pointer to the corresponding subcache. */
+#define SHMCB_MASK(pHeader, id) \
+ SHMCB_SUBCACHE((pHeader), *(id) & ((pHeader)->subcache_num - 1))
+
+/* This macro takes the same params as the last, generating two outputs for use
+ * in ap_log_error(...). */
+#define SHMCB_MASK_DBG(pHeader, id) \
+ *(id), (*(id) & ((pHeader)->subcache_num - 1))
+
+/* This macro takes a pointer to a subcache and a zero-based index and returns
+ * a pointer to the corresponding SHMCBIndex. */
+#define SHMCB_INDEX(pSubcache, num) \
+ (SHMCBIndex *)(((unsigned char *)pSubcache) + \
+ ALIGNED_SUBCACHE_SIZE + \
+ (num) * ALIGNED_INDEX_SIZE)
+
+/* This macro takes a pointer to the header and a subcache and returns a
+ * pointer to the corresponding data area. */
+#define SHMCB_DATA(pHeader, pSubcache) \
+ ((unsigned char *)(pSubcache) + (pHeader)->subcache_data_offset)
+
+/*
+ * Cyclic functions - assists in "wrap-around"/modulo logic
+ */
+
+/* Addition modulo 'mod' */
+#define SHMCB_CYCLIC_INCREMENT(val,inc,mod) \
+ (((val) + (inc)) % (mod))
+
+/* Subtraction (or "distance between") modulo 'mod' */
+#define SHMCB_CYCLIC_SPACE(val1,val2,mod) \
+ ((val2) >= (val1) ? ((val2) - (val1)) : \
+ ((val2) + (mod) - (val1)))
+
+/* A "normal-to-cyclic" memcpy. */
+static void shmcb_cyclic_ntoc_memcpy(unsigned int buf_size, unsigned char *data,
+ unsigned int dest_offset, const unsigned char *src,
+ unsigned int src_len)
+{
+ if (dest_offset + src_len < buf_size)
+ /* It be copied all in one go */
+ memcpy(data + dest_offset, src, src_len);
+ else {
+ /* Copy the two splits */
+ memcpy(data + dest_offset, src, buf_size - dest_offset);
+ memcpy(data, src + buf_size - dest_offset,
+ src_len + dest_offset - buf_size);
+ }
+}
+
+/* A "cyclic-to-normal" memcpy. */
+static void shmcb_cyclic_cton_memcpy(unsigned int buf_size, unsigned char *dest,
+ const unsigned char *data, unsigned int src_offset,
+ unsigned int src_len)
+{
+ if (src_offset + src_len < buf_size)
+ /* It be copied all in one go */
+ memcpy(dest, data + src_offset, src_len);
+ else {
+ /* Copy the two splits */
+ memcpy(dest, data + src_offset, buf_size - src_offset);
+ memcpy(dest + buf_size - src_offset, data,
+ src_len + src_offset - buf_size);
+ }
+}
+
+/* A memcmp against a cyclic data buffer. Compares SRC of length
+ * SRC_LEN against the contents of cyclic buffer DATA (which is of
+ * size BUF_SIZE), starting at offset DEST_OFFSET. Got that? Good. */
+static int shmcb_cyclic_memcmp(unsigned int buf_size, unsigned char *data,
+ unsigned int dest_offset,
+ const unsigned char *src,
+ unsigned int src_len)
+{
+ if (dest_offset + src_len < buf_size)
+ /* It be compared all in one go */
+ return memcmp(data + dest_offset, src, src_len);
+ else {
+ /* Compare the two splits */
+ int diff;
+
+ diff = memcmp(data + dest_offset, src, buf_size - dest_offset);
+ if (diff) {
+ return diff;
+ }
+ return memcmp(data, src + buf_size - dest_offset,
+ src_len + dest_offset - buf_size);
+ }
+}
+
+
+/* Prototypes for low-level subcache operations */
+static void shmcb_subcache_expire(server_rec *, SHMCBHeader *, SHMCBSubcache *,
+ apr_time_t);
+/* Returns zero on success, non-zero on failure. */
+static int shmcb_subcache_store(server_rec *s, SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ unsigned char *data, unsigned int data_len,
+ const unsigned char *id, unsigned int id_len,
+ apr_time_t expiry);
+/* Returns zero on success, non-zero on failure. */
+static int shmcb_subcache_retrieve(server_rec *, SHMCBHeader *, SHMCBSubcache *,
+ const unsigned char *id, unsigned int idlen,
+ unsigned char *data, unsigned int *datalen);
+/* Returns zero on success, non-zero on failure. */
+static int shmcb_subcache_remove(server_rec *, SHMCBHeader *, SHMCBSubcache *,
+ const unsigned char *, unsigned int);
+
+/* Returns result of the (iterator)() call, zero is success (continue) */
+static apr_status_t shmcb_subcache_iterate(ap_socache_instance_t *instance,
+ server_rec *s,
+ void *userctx,
+ SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ ap_socache_iterator_t *iterator,
+ unsigned char **buf,
+ apr_size_t *buf_len,
+ apr_pool_t *pool,
+ apr_time_t now);
+
+/*
+ * High-Level "handlers" as per ssl_scache.c
+ * subcache internals are deferred to shmcb_subcache_*** functions lower down
+ */
+
+static const char *socache_shmcb_create(ap_socache_instance_t **context,
+ const char *arg,
+ apr_pool_t *tmp, apr_pool_t *p)
+{
+ ap_socache_instance_t *ctx;
+ char *path, *cp, *cp2;
+
+ /* Allocate the context. */
+ *context = ctx = apr_pcalloc(p, sizeof *ctx);
+ ctx->pool = p;
+
+ ctx->shm_size = 1024*512; /* 512KB */
+
+ if (!arg || *arg == '\0') {
+ /* Use defaults. */
+ return NULL;
+ }
+
+ ctx->data_file = path = ap_server_root_relative(p, arg);
+
+ cp = strrchr(path, '(');
+ cp2 = path + strlen(path) - 1;
+ if (cp) {
+ char *endptr;
+ if (*cp2 != ')') {
+ return "Invalid argument: no closing parenthesis or cache size "
+ "missing after pathname with parenthesis";
+ }
+ *cp++ = '\0';
+ *cp2 = '\0';
+
+
+ ctx->shm_size = strtol(cp, &endptr, 10);
+ if (endptr != cp2) {
+ return "Invalid argument: cache size not numerical";
+ }
+
+ if (ctx->shm_size < 8192) {
+ return "Invalid argument: size has to be >= 8192 bytes";
+
+ }
+
+ if (ctx->shm_size >= SHMCB_MAX_SIZE) {
+ return apr_psprintf(tmp, "Invalid argument: size has "
+ "to be < %" APR_SIZE_T_FMT " bytes on this platform",
+ SHMCB_MAX_SIZE);
+ }
+ }
+ else if (cp2 >= path && *cp2 == ')') {
+ return "Invalid argument: no opening parenthesis";
+ }
+
+ return NULL;
+}
+
+static apr_status_t socache_shmcb_cleanup(void *arg)
+{
+ ap_socache_instance_t *ctx = arg;
+ if (ctx->shm) {
+ apr_shm_destroy(ctx->shm);
+ ctx->shm = NULL;
+ }
+ return APR_SUCCESS;
+}
+
+static apr_status_t socache_shmcb_init(ap_socache_instance_t *ctx,
+ const char *namespace,
+ const struct ap_socache_hints *hints,
+ server_rec *s, apr_pool_t *p)
+{
+ void *shm_segment;
+ apr_size_t shm_segsize;
+ apr_status_t rv;
+ SHMCBHeader *header;
+ unsigned int num_subcache, num_idx, loop;
+ apr_size_t avg_obj_size, avg_id_len;
+
+ /* Create shared memory segment */
+ if (ctx->data_file == NULL) {
+ const char *path = apr_pstrcat(p, DEFAULT_SHMCB_PREFIX, namespace,
+ DEFAULT_SHMCB_SUFFIX, NULL);
+
+ ctx->data_file = ap_runtime_dir_relative(p, path);
+ }
+
+ /* Use anonymous shm by default, fall back on name-based. */
+ rv = apr_shm_create(&ctx->shm, ctx->shm_size, NULL, p);
+ if (APR_STATUS_IS_ENOTIMPL(rv)) {
+ /* If anon shm isn't supported, fail if no named file was
+ * configured successfully; the ap_server_root_relative call
+ * above will return NULL for invalid paths. */
+ if (ctx->data_file == NULL) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00818)
+ "Could not use anonymous shm for '%s' cache",
+ namespace);
+ ctx->shm = NULL;
+ return APR_EINVAL;
+ }
+
+ /* For a name-based segment, remove it first in case of a
+ * previous unclean shutdown. */
+ apr_shm_remove(ctx->data_file, p);
+
+ rv = apr_shm_create(&ctx->shm, ctx->shm_size, ctx->data_file, p);
+ }
+
+ if (rv != APR_SUCCESS) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, rv, s, APLOGNO(00819)
+ "Could not allocate shared memory segment for shmcb "
+ "socache");
+ ctx->shm = NULL;
+ return rv;
+ }
+ apr_pool_cleanup_register(ctx->pool, ctx, socache_shmcb_cleanup,
+ apr_pool_cleanup_null);
+
+ shm_segment = apr_shm_baseaddr_get(ctx->shm);
+ shm_segsize = apr_shm_size_get(ctx->shm);
+ if (shm_segsize < (5 * ALIGNED_HEADER_SIZE)) {
+ /* the segment is ridiculously small, bail out */
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00820)
+ "shared memory segment too small");
+ return APR_ENOSPC;
+ }
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00821)
+ "shmcb_init allocated %" APR_SIZE_T_FMT
+ " bytes of shared memory",
+ shm_segsize);
+ /* Discount the header */
+ shm_segsize -= ALIGNED_HEADER_SIZE;
+ /* Select index size based on average object size hints, if given. */
+ avg_obj_size = hints && hints->avg_obj_size ? hints->avg_obj_size : 150;
+ avg_id_len = hints && hints->avg_id_len ? hints->avg_id_len : 30;
+ num_idx = (shm_segsize) / (avg_obj_size + avg_id_len);
+ num_subcache = 256;
+ while ((num_idx / num_subcache) < (2 * num_subcache))
+ num_subcache /= 2;
+ num_idx /= num_subcache;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00822)
+ "for %" APR_SIZE_T_FMT " bytes (%" APR_SIZE_T_FMT
+ " including header), recommending %u subcaches, "
+ "%u indexes each", shm_segsize,
+ shm_segsize + ALIGNED_HEADER_SIZE,
+ num_subcache, num_idx);
+ if (num_idx < 5) {
+ /* we're still too small, bail out */
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00823)
+ "shared memory segment too small");
+ return APR_ENOSPC;
+ }
+ /* OK, we're sorted */
+ ctx->header = header = shm_segment;
+ header->stat_stores = 0;
+ header->stat_replaced = 0;
+ header->stat_expiries = 0;
+ header->stat_scrolled = 0;
+ header->stat_retrieves_hit = 0;
+ header->stat_retrieves_miss = 0;
+ header->stat_removes_hit = 0;
+ header->stat_removes_miss = 0;
+ header->subcache_num = num_subcache;
+ /* Convert the subcache size (in bytes) to a value that is suitable for
+ * structure alignment on the host platform, by rounding down if necessary. */
+ header->subcache_size = (size_t)(shm_segsize / num_subcache);
+ if (header->subcache_size != APR_ALIGN_DEFAULT(header->subcache_size)) {
+ header->subcache_size = APR_ALIGN_DEFAULT(header->subcache_size) -
+ APR_ALIGN_DEFAULT(1);
+ }
+ header->subcache_data_offset = ALIGNED_SUBCACHE_SIZE +
+ num_idx * ALIGNED_INDEX_SIZE;
+ header->subcache_data_size = header->subcache_size -
+ header->subcache_data_offset;
+ header->index_num = num_idx;
+
+ /* Output trace info */
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00824)
+ "shmcb_init_memory choices follow");
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00825)
+ "subcache_num = %u", header->subcache_num);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00826)
+ "subcache_size = %u", header->subcache_size);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00827)
+ "subcache_data_offset = %u", header->subcache_data_offset);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00828)
+ "subcache_data_size = %u", header->subcache_data_size);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00829)
+ "index_num = %u", header->index_num);
+ /* The header is done, make the caches empty */
+ for (loop = 0; loop < header->subcache_num; loop++) {
+ SHMCBSubcache *subcache = SHMCB_SUBCACHE(header, loop);
+ subcache->idx_pos = subcache->idx_used = 0;
+ subcache->data_pos = subcache->data_used = 0;
+ }
+ ap_log_error(APLOG_MARK, APLOG_INFO, 0, s, APLOGNO(00830)
+ "Shared memory socache initialised");
+ /* Success ... */
+
+ return APR_SUCCESS;
+}
+
+static void socache_shmcb_destroy(ap_socache_instance_t *ctx, server_rec *s)
+{
+ if (ctx) {
+ apr_pool_cleanup_run(ctx->pool, ctx, socache_shmcb_cleanup);
+ }
+}
+
+static apr_status_t socache_shmcb_store(ap_socache_instance_t *ctx,
+ server_rec *s, const unsigned char *id,
+ unsigned int idlen, apr_time_t expiry,
+ unsigned char *encoded,
+ unsigned int len_encoded,
+ apr_pool_t *p)
+{
+ SHMCBHeader *header = ctx->header;
+ SHMCBSubcache *subcache = SHMCB_MASK(header, id);
+ int tryreplace;
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00831)
+ "socache_shmcb_store (0x%02x -> subcache %d)",
+ SHMCB_MASK_DBG(header, id));
+ /* XXX: Says who? Why shouldn't this be acceptable, or padded if not? */
+ if (idlen < 4) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00832) "unusably short id provided "
+ "(%u bytes)", idlen);
+ return APR_EINVAL;
+ }
+ tryreplace = shmcb_subcache_remove(s, header, subcache, id, idlen);
+ if (shmcb_subcache_store(s, header, subcache, encoded,
+ len_encoded, id, idlen, expiry)) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00833)
+ "can't store an socache entry!");
+ return APR_ENOSPC;
+ }
+ if (tryreplace == 0) {
+ header->stat_replaced++;
+ }
+ else {
+ header->stat_stores++;
+ }
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00834)
+ "leaving socache_shmcb_store successfully");
+ return APR_SUCCESS;
+}
+
+static apr_status_t socache_shmcb_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)
+{
+ SHMCBHeader *header = ctx->header;
+ SHMCBSubcache *subcache = SHMCB_MASK(header, id);
+ int rv;
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00835)
+ "socache_shmcb_retrieve (0x%02x -> subcache %d)",
+ SHMCB_MASK_DBG(header, id));
+
+ /* Get the entry corresponding to the id, if it exists. */
+ rv = shmcb_subcache_retrieve(s, header, subcache, id, idlen,
+ dest, destlen);
+ if (rv == 0)
+ header->stat_retrieves_hit++;
+ else
+ header->stat_retrieves_miss++;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00836)
+ "leaving socache_shmcb_retrieve successfully");
+
+ return rv == 0 ? APR_SUCCESS : APR_NOTFOUND;
+}
+
+static apr_status_t socache_shmcb_remove(ap_socache_instance_t *ctx,
+ server_rec *s, const unsigned char *id,
+ unsigned int idlen, apr_pool_t *p)
+{
+ SHMCBHeader *header = ctx->header;
+ SHMCBSubcache *subcache = SHMCB_MASK(header, id);
+ apr_status_t rv;
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00837)
+ "socache_shmcb_remove (0x%02x -> subcache %d)",
+ SHMCB_MASK_DBG(header, id));
+ if (idlen < 4) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00838) "unusably short id provided "
+ "(%u bytes)", idlen);
+ return APR_EINVAL;
+ }
+ if (shmcb_subcache_remove(s, header, subcache, id, idlen) == 0) {
+ header->stat_removes_hit++;
+ rv = APR_SUCCESS;
+ } else {
+ header->stat_removes_miss++;
+ rv = APR_NOTFOUND;
+ }
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00839)
+ "leaving socache_shmcb_remove successfully");
+
+ return rv;
+}
+
+static void socache_shmcb_status(ap_socache_instance_t *ctx,
+ request_rec *r, int flags)
+{
+ server_rec *s = r->server;
+ SHMCBHeader *header = ctx->header;
+ unsigned int loop, total = 0, cache_total = 0, non_empty_subcaches = 0;
+ apr_time_t idx_expiry, min_expiry = 0, max_expiry = 0;
+ apr_time_t now = apr_time_now();
+ double expiry_total = 0;
+ int index_pct, cache_pct;
+
+ AP_DEBUG_ASSERT(header->subcache_num > 0);
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00840) "inside shmcb_status");
+ /* Perform the iteration inside the mutex to avoid corruption or invalid
+ * pointer arithmetic. The rest of our logic uses read-only header data so
+ * doesn't need the lock. */
+ /* Iterate over the subcaches */
+ for (loop = 0; loop < header->subcache_num; loop++) {
+ SHMCBSubcache *subcache = SHMCB_SUBCACHE(header, loop);
+ shmcb_subcache_expire(s, header, subcache, now);
+ total += subcache->idx_used;
+ cache_total += subcache->data_used;
+ if (subcache->idx_used) {
+ SHMCBIndex *idx = SHMCB_INDEX(subcache, subcache->idx_pos);
+ non_empty_subcaches++;
+ idx_expiry = idx->expires;
+ expiry_total += (double)idx_expiry;
+ max_expiry = ((idx_expiry > max_expiry) ? idx_expiry : max_expiry);
+ if (!min_expiry)
+ min_expiry = idx_expiry;
+ else
+ min_expiry = ((idx_expiry < min_expiry) ? idx_expiry : min_expiry);
+ }
+ }
+ index_pct = (100 * total) / (header->index_num *
+ header->subcache_num);
+ cache_pct = (100 * cache_total) / (header->subcache_data_size *
+ header->subcache_num);
+ /* Generate Output */
+ if (!(flags & AP_STATUS_SHORT)) {
+ ap_rprintf(r, "cache type: <b>SHMCB</b>, shared memory: <b>%" APR_SIZE_T_FMT "</b> "
+ "bytes, current entries: <b>%d</b><br>",
+ ctx->shm_size, total);
+ ap_rprintf(r, "subcaches: <b>%d</b>, indexes per subcache: <b>%d</b><br>",
+ header->subcache_num, header->index_num);
+ if (non_empty_subcaches) {
+ apr_time_t average_expiry = (apr_time_t)(expiry_total / (double)non_empty_subcaches);
+ ap_rprintf(r, "time left on oldest entries' objects: ");
+ if (now < average_expiry)
+ ap_rprintf(r, "avg: <b>%d</b> seconds, (range: %d...%d)<br>",
+ (int)apr_time_sec(average_expiry - now),
+ (int)apr_time_sec(min_expiry - now),
+ (int)apr_time_sec(max_expiry - now));
+ else
+ ap_rprintf(r, "expiry_threshold: <b>Calculation error!</b><br>");
+ }
+
+ ap_rprintf(r, "index usage: <b>%d%%</b>, cache usage: <b>%d%%</b><br>",
+ index_pct, cache_pct);
+ ap_rprintf(r, "total entries stored since starting: <b>%lu</b><br>",
+ header->stat_stores);
+ ap_rprintf(r, "total entries replaced since starting: <b>%lu</b><br>",
+ header->stat_replaced);
+ ap_rprintf(r, "total entries expired since starting: <b>%lu</b><br>",
+ header->stat_expiries);
+ ap_rprintf(r, "total (pre-expiry) entries scrolled out of the cache: "
+ "<b>%lu</b><br>", header->stat_scrolled);
+ ap_rprintf(r, "total retrieves since starting: <b>%lu</b> hit, "
+ "<b>%lu</b> miss<br>", header->stat_retrieves_hit,
+ header->stat_retrieves_miss);
+ ap_rprintf(r, "total removes since starting: <b>%lu</b> hit, "
+ "<b>%lu</b> miss<br>", header->stat_removes_hit,
+ header->stat_removes_miss);
+ }
+ else {
+ ap_rputs("CacheType: SHMCB\n", r);
+ ap_rprintf(r, "CacheSharedMemory: %" APR_SIZE_T_FMT "\n",
+ ctx->shm_size);
+ ap_rprintf(r, "CacheCurrentEntries: %d\n", total);
+ ap_rprintf(r, "CacheSubcaches: %d\n", header->subcache_num);
+ ap_rprintf(r, "CacheIndexesPerSubcaches: %d\n", header->index_num);
+ if (non_empty_subcaches) {
+ apr_time_t average_expiry = (apr_time_t)(expiry_total / (double)non_empty_subcaches);
+ if (now < average_expiry) {
+ ap_rprintf(r, "CacheTimeLeftOldestAvg: %d\n", (int)apr_time_sec(average_expiry - now));
+ ap_rprintf(r, "CacheTimeLeftOldestMin: %d\n", (int)apr_time_sec(min_expiry - now));
+ ap_rprintf(r, "CacheTimeLeftOldestMax: %d\n", (int)apr_time_sec(max_expiry - now));
+ }
+ }
+
+ ap_rprintf(r, "CacheIndexUsage: %d%%\n", index_pct);
+ ap_rprintf(r, "CacheUsage: %d%%\n", cache_pct);
+ ap_rprintf(r, "CacheStoreCount: %lu\n", header->stat_stores);
+ ap_rprintf(r, "CacheReplaceCount: %lu\n", header->stat_replaced);
+ ap_rprintf(r, "CacheExpireCount: %lu\n", header->stat_expiries);
+ ap_rprintf(r, "CacheDiscardCount: %lu\n", header->stat_scrolled);
+ ap_rprintf(r, "CacheRetrieveHitCount: %lu\n", header->stat_retrieves_hit);
+ ap_rprintf(r, "CacheRetrieveMissCount: %lu\n", header->stat_retrieves_miss);
+ ap_rprintf(r, "CacheRemoveHitCount: %lu\n", header->stat_removes_hit);
+ ap_rprintf(r, "CacheRemoveMissCount: %lu\n", header->stat_removes_miss);
+ }
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00841) "leaving shmcb_status");
+}
+
+static apr_status_t socache_shmcb_iterate(ap_socache_instance_t *instance,
+ server_rec *s, void *userctx,
+ ap_socache_iterator_t *iterator,
+ apr_pool_t *pool)
+{
+ SHMCBHeader *header = instance->header;
+ unsigned int loop;
+ apr_time_t now = apr_time_now();
+ apr_status_t rv = APR_SUCCESS;
+ apr_size_t buflen = 0;
+ unsigned char *buf = NULL;
+
+ /* Perform the iteration inside the mutex to avoid corruption or invalid
+ * pointer arithmetic. The rest of our logic uses read-only header data so
+ * doesn't need the lock. */
+ /* Iterate over the subcaches */
+ for (loop = 0; loop < header->subcache_num && rv == APR_SUCCESS; loop++) {
+ SHMCBSubcache *subcache = SHMCB_SUBCACHE(header, loop);
+ rv = shmcb_subcache_iterate(instance, s, userctx, header, subcache,
+ iterator, &buf, &buflen, pool, now);
+ }
+ return rv;
+}
+
+/*
+ * Subcache-level cache operations
+ */
+
+static void shmcb_subcache_expire(server_rec *s, SHMCBHeader *header,
+ SHMCBSubcache *subcache, apr_time_t now)
+{
+ unsigned int loop = 0, freed = 0, expired = 0;
+ unsigned int new_idx_pos = subcache->idx_pos;
+ SHMCBIndex *idx = NULL;
+
+ while (loop < subcache->idx_used) {
+ idx = SHMCB_INDEX(subcache, new_idx_pos);
+ if (idx->removed)
+ freed++;
+ else if (idx->expires <= now)
+ expired++;
+ else
+ /* not removed and not expired yet, we're done iterating */
+ break;
+ loop++;
+ new_idx_pos = SHMCB_CYCLIC_INCREMENT(new_idx_pos, 1, header->index_num);
+ }
+ if (!loop)
+ /* Nothing to do */
+ return;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00842)
+ "expiring %u and reclaiming %u removed socache entries",
+ expired, freed);
+ if (loop == subcache->idx_used) {
+ /* We're expiring everything, piece of cake */
+ subcache->idx_used = 0;
+ subcache->data_used = 0;
+ } else {
+ /* There remain other indexes, so we can use idx to adjust 'data' */
+ unsigned int diff = SHMCB_CYCLIC_SPACE(subcache->data_pos,
+ idx->data_pos,
+ header->subcache_data_size);
+ /* Adjust the indexes */
+ subcache->idx_used -= loop;
+ subcache->idx_pos = new_idx_pos;
+ /* Adjust the data area */
+ subcache->data_used -= diff;
+ subcache->data_pos = idx->data_pos;
+ }
+ header->stat_expiries += expired;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00843)
+ "we now have %u socache entries", subcache->idx_used);
+}
+
+static int shmcb_subcache_store(server_rec *s, SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ unsigned char *data, unsigned int data_len,
+ const unsigned char *id, unsigned int id_len,
+ apr_time_t expiry)
+{
+ unsigned int data_offset, new_idx, id_offset;
+ SHMCBIndex *idx;
+ unsigned int total_len = id_len + data_len;
+
+ /* Sanity check the input */
+ if (total_len > header->subcache_data_size) {
+ ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00844)
+ "inserting socache entry larger (%d) than subcache data area (%d)",
+ total_len, header->subcache_data_size);
+ return -1;
+ }
+
+ /* First reclaim space from removed and expired records. */
+ shmcb_subcache_expire(s, header, subcache, apr_time_now());
+
+ /* Loop until there is enough space to insert
+ * XXX: This should first compress out-of-order expiries and
+ * removed records, and then force-remove oldest-first
+ */
+ if (header->subcache_data_size - subcache->data_used < total_len
+ || subcache->idx_used == header->index_num) {
+ unsigned int loop = 0;
+
+ idx = SHMCB_INDEX(subcache, subcache->idx_pos);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00845)
+ "about to force-expire, subcache: idx_used=%d, "
+ "data_used=%d", subcache->idx_used, subcache->data_used);
+ do {
+ SHMCBIndex *idx2;
+
+ /* Adjust the indexes by one */
+ subcache->idx_pos = SHMCB_CYCLIC_INCREMENT(subcache->idx_pos, 1,
+ header->index_num);
+ subcache->idx_used--;
+ if (!subcache->idx_used) {
+ /* There's nothing left */
+ subcache->data_used = 0;
+ break;
+ }
+ /* Adjust the data */
+ idx2 = SHMCB_INDEX(subcache, subcache->idx_pos);
+ subcache->data_used -= SHMCB_CYCLIC_SPACE(idx->data_pos, idx2->data_pos,
+ header->subcache_data_size);
+ subcache->data_pos = idx2->data_pos;
+ /* Stats */
+ header->stat_scrolled++;
+ /* Loop admin */
+ idx = idx2;
+ loop++;
+ } while (header->subcache_data_size - subcache->data_used < total_len);
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00846)
+ "finished force-expire, subcache: idx_used=%d, "
+ "data_used=%d", subcache->idx_used, subcache->data_used);
+ }
+
+ /* HERE WE ASSUME THAT THE NEW ENTRY SHOULD GO ON THE END! I'M NOT
+ * CHECKING WHETHER IT SHOULD BE GENUINELY "INSERTED" SOMEWHERE.
+ *
+ * We aught to fix that. httpd (never mind third party modules)
+ * does not promise to perform any processing in date order
+ * (c.f. FAQ "My log entries are not in date order!")
+ */
+ /* Insert the id */
+ id_offset = SHMCB_CYCLIC_INCREMENT(subcache->data_pos, subcache->data_used,
+ header->subcache_data_size);
+ shmcb_cyclic_ntoc_memcpy(header->subcache_data_size,
+ SHMCB_DATA(header, subcache), id_offset,
+ id, id_len);
+ subcache->data_used += id_len;
+ /* Insert the data */
+ data_offset = SHMCB_CYCLIC_INCREMENT(subcache->data_pos, subcache->data_used,
+ header->subcache_data_size);
+ shmcb_cyclic_ntoc_memcpy(header->subcache_data_size,
+ SHMCB_DATA(header, subcache), data_offset,
+ data, data_len);
+ subcache->data_used += data_len;
+ /* Insert the index */
+ new_idx = SHMCB_CYCLIC_INCREMENT(subcache->idx_pos, subcache->idx_used,
+ header->index_num);
+ idx = SHMCB_INDEX(subcache, new_idx);
+ idx->expires = expiry;
+ idx->data_pos = id_offset;
+ idx->data_used = total_len;
+ idx->id_len = id_len;
+ idx->removed = 0;
+ subcache->idx_used++;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00847)
+ "insert happened at idx=%d, data=(%u:%u)", new_idx,
+ id_offset, data_offset);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00848)
+ "finished insert, subcache: idx_pos/idx_used=%d/%d, "
+ "data_pos/data_used=%d/%d",
+ subcache->idx_pos, subcache->idx_used,
+ subcache->data_pos, subcache->data_used);
+ return 0;
+}
+
+static int shmcb_subcache_retrieve(server_rec *s, SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ const unsigned char *id, unsigned int idlen,
+ unsigned char *dest, unsigned int *destlen)
+{
+ unsigned int pos;
+ unsigned int loop = 0;
+ apr_time_t now = apr_time_now();
+
+ pos = subcache->idx_pos;
+
+ while (loop < subcache->idx_used) {
+ SHMCBIndex *idx = SHMCB_INDEX(subcache, pos);
+
+ /* Only consider 'idx' if the id matches, and the "removed"
+ * flag isn't set, and the record is not expired.
+ * Check the data length too to avoid a buffer overflow
+ * in case of corruption, which should be impossible,
+ * but it's cheap to be safe. */
+ if (!idx->removed
+ && idx->id_len == idlen
+ && (idx->data_used - idx->id_len) <= *destlen
+ && shmcb_cyclic_memcmp(header->subcache_data_size,
+ SHMCB_DATA(header, subcache),
+ idx->data_pos, id, idx->id_len) == 0) {
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00849)
+ "match at idx=%d, data=%d", pos, idx->data_pos);
+ if (idx->expires > now) {
+ unsigned int data_offset;
+
+ /* Find the offset of the data segment, after the id */
+ data_offset = SHMCB_CYCLIC_INCREMENT(idx->data_pos,
+ idx->id_len,
+ header->subcache_data_size);
+
+ *destlen = idx->data_used - idx->id_len;
+
+ /* Copy out the data */
+ shmcb_cyclic_cton_memcpy(header->subcache_data_size,
+ dest, SHMCB_DATA(header, subcache),
+ data_offset, *destlen);
+
+ return 0;
+ }
+ else {
+ /* Already stale, quietly remove and treat as not-found */
+ idx->removed = 1;
+ header->stat_expiries++;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00850)
+ "shmcb_subcache_retrieve discarding expired entry");
+ return -1;
+ }
+ }
+ /* Increment */
+ loop++;
+ pos = SHMCB_CYCLIC_INCREMENT(pos, 1, header->index_num);
+ }
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00851)
+ "shmcb_subcache_retrieve found no match");
+ return -1;
+}
+
+static int shmcb_subcache_remove(server_rec *s, SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ const unsigned char *id,
+ unsigned int idlen)
+{
+ unsigned int pos;
+ unsigned int loop = 0;
+
+ pos = subcache->idx_pos;
+ while (loop < subcache->idx_used) {
+ SHMCBIndex *idx = SHMCB_INDEX(subcache, pos);
+
+ /* Only consider 'idx' if the id matches, and the "removed"
+ * flag isn't set. */
+ if (!idx->removed && idx->id_len == idlen
+ && shmcb_cyclic_memcmp(header->subcache_data_size,
+ SHMCB_DATA(header, subcache),
+ idx->data_pos, id, idx->id_len) == 0) {
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00852)
+ "possible match at idx=%d, data=%d", pos, idx->data_pos);
+
+ /* Found the matching entry, remove it quietly. */
+ idx->removed = 1;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00853)
+ "shmcb_subcache_remove removing matching entry");
+ return 0;
+ }
+ /* Increment */
+ loop++;
+ pos = SHMCB_CYCLIC_INCREMENT(pos, 1, header->index_num);
+ }
+
+ return -1; /* failure */
+}
+
+
+static apr_status_t shmcb_subcache_iterate(ap_socache_instance_t *instance,
+ server_rec *s,
+ void *userctx,
+ SHMCBHeader *header,
+ SHMCBSubcache *subcache,
+ ap_socache_iterator_t *iterator,
+ unsigned char **buf,
+ apr_size_t *buf_len,
+ apr_pool_t *pool,
+ apr_time_t now)
+{
+ unsigned int pos;
+ unsigned int loop = 0;
+ apr_status_t rv;
+
+ pos = subcache->idx_pos;
+ while (loop < subcache->idx_used) {
+ SHMCBIndex *idx = SHMCB_INDEX(subcache, pos);
+
+ /* Only consider 'idx' if the "removed" flag isn't set. */
+ if (!idx->removed) {
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00854)
+ "iterating idx=%d, data=%d", pos, idx->data_pos);
+ if (idx->expires > now) {
+ unsigned char *id = *buf;
+ unsigned char *dest;
+ unsigned int data_offset, dest_len;
+ apr_size_t buf_req;
+
+ /* Find the offset of the data segment, after the id */
+ data_offset = SHMCB_CYCLIC_INCREMENT(idx->data_pos,
+ idx->id_len,
+ header->subcache_data_size);
+
+ dest_len = idx->data_used - idx->id_len;
+
+ buf_req = APR_ALIGN_DEFAULT(idx->id_len + 1)
+ + APR_ALIGN_DEFAULT(dest_len + 1);
+
+ if (buf_req > *buf_len) {
+ /* Grow to ~150% of this buffer requirement on resize
+ * always using APR_ALIGN_DEFAULT sized pages
+ */
+ *buf_len = buf_req + APR_ALIGN_DEFAULT(buf_req / 2);
+ *buf = apr_palloc(pool, *buf_len);
+ id = *buf;
+ }
+
+ dest = *buf + APR_ALIGN_DEFAULT(idx->id_len + 1);
+
+ /* Copy out the data, because it's potentially cyclic */
+ shmcb_cyclic_cton_memcpy(header->subcache_data_size, id,
+ SHMCB_DATA(header, subcache),
+ idx->data_pos, idx->id_len);
+ id[idx->id_len] = '\0';
+
+ shmcb_cyclic_cton_memcpy(header->subcache_data_size, dest,
+ SHMCB_DATA(header, subcache),
+ data_offset, dest_len);
+ dest[dest_len] = '\0';
+
+ rv = iterator(instance, s, userctx, id, idx->id_len,
+ dest, dest_len, pool);
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, s, APLOGNO(00855)
+ "shmcb entry iterated");
+ if (rv != APR_SUCCESS)
+ return rv;
+ }
+ else {
+ /* Already stale, quietly remove and treat as not-found */
+ idx->removed = 1;
+ header->stat_expiries++;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00856)
+ "shmcb_subcache_iterate discarding expired entry");
+ }
+ }
+ /* Increment */
+ loop++;
+ pos = SHMCB_CYCLIC_INCREMENT(pos, 1, header->index_num);
+ }
+
+ return APR_SUCCESS;
+}
+
+static const ap_socache_provider_t socache_shmcb = {
+ "shmcb",
+ AP_SOCACHE_FLAG_NOTMPSAFE,
+ socache_shmcb_create,
+ socache_shmcb_init,
+ socache_shmcb_destroy,
+ socache_shmcb_store,
+ socache_shmcb_retrieve,
+ socache_shmcb_remove,
+ socache_shmcb_status,
+ socache_shmcb_iterate
+};
+
+static void register_hooks(apr_pool_t *p)
+{
+ ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP, "shmcb",
+ AP_SOCACHE_PROVIDER_VERSION,
+ &socache_shmcb);
+
+ /* Also register shmcb under the default provider name. */
+ ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP,
+ AP_SOCACHE_DEFAULT_PROVIDER,
+ AP_SOCACHE_PROVIDER_VERSION,
+ &socache_shmcb);
+}
+
+AP_DECLARE_MODULE(socache_shmcb) = {
+ STANDARD20_MODULE_STUFF,
+ NULL, NULL, NULL, NULL, NULL,
+ register_hooks
+};