mod_disk_cache.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

    rv = apr_file_writev(fd, (const struct iovec *) &iov, 1,
                         &amt);
    return rv;
}

static apr_status_t store_headers(cache_handle_t *h, request_rec *r, cache_info *info)
{
    disk_cache_conf *conf = ap_get_module_config(r->server->module_config,
                                                 &disk_cache_module);
    apr_status_t rv;
    apr_size_t amt;
    disk_cache_object_t *dobj = (disk_cache_object_t*) h->cache_obj->vobj;

    disk_cache_info_t disk_info;
    struct iovec iov[2];

    /* This is flaky... we need to manage the cache_info differently */
    h->cache_obj->info = *info;

    if (r->headers_out) {
        const char *tmp;

        tmp = apr_table_get(r->headers_out, "Vary");

        if (tmp) {
            apr_array_header_t* varray;
            apr_uint32_t format = VARY_FORMAT_VERSION;

            /* If we were initially opened as a vary format, rollback
             * that internal state for the moment so we can recreate the
             * vary format hints in the appropriate directory.
             */
            if (dobj->prefix) {
                dobj->hdrsfile = dobj->prefix;
                dobj->prefix = NULL;
            }

            mkdir_structure(conf, dobj->hdrsfile, r->pool);

            rv = apr_file_mktemp(&dobj->tfd, dobj->tempfile,
                                 APR_CREATE | APR_WRITE | APR_BINARY | APR_EXCL,
                                 r->pool);

            if (rv != APR_SUCCESS) {
                return rv;
            }

            amt = sizeof(format);
            apr_file_write(dobj->tfd, &format, &amt);

            amt = sizeof(info->expire);
            apr_file_write(dobj->tfd, &info->expire, &amt);

            varray = apr_array_make(r->pool, 6, sizeof(char*));
            tokens_to_array(r->pool, tmp, varray);

            store_array(dobj->tfd, varray);

            apr_file_close(dobj->tfd);

            dobj->tfd = NULL;

            rv = safe_file_rename(conf, dobj->tempfile, dobj->hdrsfile,
                                  r->pool);
            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_WARNING, rv, r->server,
                    "disk_cache: rename tempfile to varyfile failed: %s -> %s",
                    dobj->tempfile, dobj->hdrsfile);
                apr_file_remove(dobj->tempfile, r->pool);
                return rv;
            }

            dobj->tempfile = apr_pstrcat(r->pool, conf->cache_root, AP_TEMPFILE, NULL);
            tmp = regen_key(r->pool, r->headers_in, varray, dobj->name);
            dobj->prefix = dobj->hdrsfile;
            dobj->hashfile = NULL;
            dobj->datafile = data_file(r->pool, conf, dobj, tmp);
            dobj->hdrsfile = header_file(r->pool, conf, dobj, tmp);
        }
    }


    rv = apr_file_mktemp(&dobj->hfd, dobj->tempfile,
                         APR_CREATE | APR_WRITE | APR_BINARY |
                         APR_BUFFERED | APR_EXCL, r->pool);

    if (rv != APR_SUCCESS) {
        return rv;
    }

    disk_info.format = DISK_FORMAT_VERSION;
    disk_info.date = info->date;
    disk_info.expire = info->expire;
    disk_info.entity_version = dobj->disk_info.entity_version++;
    disk_info.request_time = info->request_time;
    disk_info.response_time = info->response_time;
    disk_info.status = info->status;

    disk_info.name_len = strlen(dobj->name);

    iov[0].iov_base = (void*)&disk_info;
    iov[0].iov_len = sizeof(disk_cache_info_t);
    iov[1].iov_base = (void*)dobj->name;
    iov[1].iov_len = disk_info.name_len;

    rv = apr_file_writev(dobj->hfd, (const struct iovec *) &iov, 2, &amt);
    if (rv != APR_SUCCESS) {
        return rv;
    }

    if (r->headers_out) {
        apr_table_t *headers_out;

        headers_out = ap_cache_cacheable_hdrs_out(r->pool, r->headers_out,
                                                  r->server);

        if (!apr_table_get(headers_out, "Content-Type")
            && r->content_type) {
            apr_table_setn(headers_out, "Content-Type",
                           ap_make_content_type(r, r->content_type));
        }

        headers_out = apr_table_overlay(r->pool, headers_out,
                                        r->err_headers_out);
        rv = store_table(dobj->hfd, headers_out);
        if (rv != APR_SUCCESS) {
            return rv;
        }
    }

    /* Parse the vary header and dump those fields from the headers_in. */
    /* FIXME: Make call to the same thing cache_select calls to crack Vary. */
    if (r->headers_in) {
        apr_table_t *headers_in;

        headers_in = ap_cache_cacheable_hdrs_out(r->pool, r->headers_in,
                                                 r->server);
        rv = store_table(dobj->hfd, headers_in);
        if (rv != APR_SUCCESS) {
            return rv;
        }
    }

    apr_file_close(dobj->hfd); /* flush and close */

    /* Remove old file with the same name. If remove fails, then
     * perhaps we need to create the directory tree where we are
     * about to write the new headers file.
     */
    rv = apr_file_remove(dobj->hdrsfile, r->pool);
    if (rv != APR_SUCCESS) {
        mkdir_structure(conf, dobj->hdrsfile, r->pool);
    }

    rv = safe_file_rename(conf, dobj->tempfile, dobj->hdrsfile, r->pool);
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, r->server,
                     "disk_cache: rename tempfile to hdrsfile failed: %s -> %s",
                     dobj->tempfile, dobj->hdrsfile);
        apr_file_remove(dobj->tempfile, r->pool);
        return rv;
    }

    dobj->tempfile = apr_pstrcat(r->pool, conf->cache_root, AP_TEMPFILE, NULL);

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                 "disk_cache: Stored headers for URL %s",  dobj->name);
    return APR_SUCCESS;
}

static apr_status_t store_body(cache_handle_t *h, request_rec *r,
                               apr_bucket_brigade *bb)
{
    apr_bucket *e;
    apr_status_t rv;
    disk_cache_object_t *dobj = (disk_cache_object_t *) h->cache_obj->vobj;
    disk_cache_conf *conf = ap_get_module_config(r->server->module_config,
                                                 &disk_cache_module);

    /* We write to a temp file and then atomically rename the file over
     * in file_cache_el_final().
     */
    if (!dobj->tfd) {
        rv = apr_file_mktemp(&dobj->tfd, dobj->tempfile,
                             APR_CREATE | APR_WRITE | APR_BINARY |
                             APR_BUFFERED | APR_EXCL, r->pool);
        if (rv != APR_SUCCESS) {
            return rv;
        }
        dobj->file_size = 0;
    }

    for (e = APR_BRIGADE_FIRST(bb);
         e != APR_BRIGADE_SENTINEL(bb);
         e = APR_BUCKET_NEXT(e))
    {
        const char *str;
        apr_size_t length, written;
        rv = apr_bucket_read(e, &str, &length, APR_BLOCK_READ);
        if (rv != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                         "cache_disk: Error when reading bucket for URL %s",
                         h->cache_obj->key);
            /* Remove the intermediate cache file and return non-APR_SUCCESS */
            file_cache_errorcleanup(dobj, r);
            return rv;
        }
        rv = apr_file_write_full(dobj->tfd, str, length, &written);
        if (rv != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                         "cache_disk: Error when writing cache file for URL %s",
                         h->cache_obj->key);
            /* Remove the intermediate cache file and return non-APR_SUCCESS */
            file_cache_errorcleanup(dobj, r);
            return rv;
        }
        dobj->file_size += written;
        if (dobj->file_size > conf->maxfs) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "cache_disk: URL %s failed the size check "
                         "(%" APR_OFF_T_FMT " > %" APR_OFF_T_FMT ")",
                         h->cache_obj->key, dobj->file_size, conf->maxfs);
            /* Remove the intermediate cache file and return non-APR_SUCCESS */
            file_cache_errorcleanup(dobj, r);
            return APR_EGENERAL;
        }
    }

    /* Was this the final bucket? If yes, close the temp file and perform
     * sanity checks.
     */
    if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(bb))) {
        if (r->connection->aborted || r->no_cache) {
            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
                         "disk_cache: Discarding body for URL %s "
                         "because connection has been aborted.",
                         h->cache_obj->key);
            /* Remove the intermediate cache file and return non-APR_SUCCESS */
            file_cache_errorcleanup(dobj, r);
            return APR_EGENERAL;
        }
        if (dobj->file_size < conf->minfs) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "cache_disk: URL %s failed the size check "
                         "(%" APR_OFF_T_FMT " < %" APR_OFF_T_FMT ")",
                         h->cache_obj->key, dobj->file_size, conf->minfs);
            /* Remove the intermediate cache file and return non-APR_SUCCESS */
            file_cache_errorcleanup(dobj, r);
            return APR_EGENERAL;
        }

        /* All checks were fine. Move tempfile to final destination */
        /* Link to the perm file, and close the descriptor */
        file_cache_el_final(dobj, r);
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "disk_cache: Body for URL %s cached.",  dobj->name);
    }

    return APR_SUCCESS;
}

static void *create_config(apr_pool_t *p, server_rec *s)
{
    disk_cache_conf *conf = apr_pcalloc(p, sizeof(disk_cache_conf));

    /* XXX: Set default values */
    conf->dirlevels = DEFAULT_DIRLEVELS;
    conf->dirlength = DEFAULT_DIRLENGTH;
    conf->maxfs = DEFAULT_MAX_FILE_SIZE;
    conf->minfs = DEFAULT_MIN_FILE_SIZE;

    conf->cache_root = NULL;
    conf->cache_root_len = 0;

    return conf;
}

/*
 * mod_disk_cache configuration directives handlers.
 */
static const char
*set_cache_root(cmd_parms *parms, void *in_struct_ptr, const char *arg)
{
    disk_cache_conf *conf = ap_get_module_config(parms->server->module_config,
                                                 &disk_cache_module);
    conf->cache_root = arg;
    conf->cache_root_len = strlen(arg);
    /* TODO: canonicalize cache_root and strip off any trailing slashes */

    return NULL;
}

/*
 * Consider eliminating the next two directives in favor of
 * Ian's prime number hash...
 * key = hash_fn( r->uri)
 * filename = "/key % prime1 /key %prime2/key %prime3"
 */
static const char
*set_cache_dirlevels(cmd_parms *parms, void *in_struct_ptr, const char *arg)
{
    disk_cache_conf *conf = ap_get_module_config(parms->server->module_config,
                                                 &disk_cache_module);
    int val = atoi(arg);
    if (val < 1)
        return "CacheDirLevels value must be an integer greater than 0";
    if (val * conf->dirlength > CACHEFILE_LEN)
        return "CacheDirLevels*CacheDirLength value must not be higher than 20";
    conf->dirlevels = val;
    return NULL;
}
static const char
*set_cache_dirlength(cmd_parms *parms, void *in_struct_ptr, const char *arg)
{
    disk_cache_conf *conf = ap_get_module_config(parms->server->module_config,
                                                 &disk_cache_module);
    int val = atoi(arg);
    if (val < 1)
        return "CacheDirLength value must be an integer greater than 0";
    if (val * conf->dirlevels > CACHEFILE_LEN)
        return "CacheDirLevels*CacheDirLength value must not be higher than 20";

    conf->dirlength = val;
    return NULL;
}

static const char
*set_cache_minfs(cmd_parms *parms, void *in_struct_ptr, const char *arg)
{
    disk_cache_conf *conf = ap_get_module_config(parms->server->module_config,
                                                 &disk_cache_module);

    if (apr_strtoff(&conf->minfs, arg, NULL, 0) != APR_SUCCESS ||
            conf->minfs < 0) 
    {
        return "CacheMinFileSize argument must be a non-negative integer representing the min size of a file to cache in bytes.";
    }
    return NULL;
}

static const char
*set_cache_maxfs(cmd_parms *parms, void *in_struct_ptr, const char *arg)
{
    disk_cache_conf *conf = ap_get_module_config(parms->server->module_config,
                                                 &disk_cache_module);
    if (apr_strtoff(&conf->maxfs, arg, NULL, 0) != APR_SUCCESS ||
            conf->maxfs < 0) 
    {
        return "CacheMaxFileSize argument must be a non-negative integer representing the max size of a file to cache in bytes.";
    }
    return NULL;
}

static const command_rec disk_cache_cmds[] =
{
    AP_INIT_TAKE1("CacheRoot", set_cache_root, NULL, RSRC_CONF,
                 "The directory to store cache files"),
    AP_INIT_TAKE1("CacheDirLevels", set_cache_dirlevels, NULL, RSRC_CONF,
                  "The number of levels of subdirectories in the cache"),
    AP_INIT_TAKE1("CacheDirLength", set_cache_dirlength, NULL, RSRC_CONF,
                  "The number of characters in subdirectory names"),
    AP_INIT_TAKE1("CacheMinFileSize", set_cache_minfs, NULL, RSRC_CONF,
                  "The minimum file size to cache a document"),
    AP_INIT_TAKE1("CacheMaxFileSize", set_cache_maxfs, NULL, RSRC_CONF,
                  "The maximum file size to cache a document"),
    {NULL}
};

static const cache_provider cache_disk_provider =
{
    &remove_entity,
    &store_headers,
    &store_body,
    &recall_headers,
    &recall_body,
    &create_entity,
    &open_entity,
    &remove_url,
};

static void disk_cache_register_hook(apr_pool_t *p)
{
    /* cache initializer */
    ap_register_provider(p, CACHE_PROVIDER_GROUP, "disk", "0",
                         &cache_disk_provider);
}

module AP_MODULE_DECLARE_DATA disk_cache_module = {
    STANDARD20_MODULE_STUFF,
    NULL,                       /* create per-directory config structure */
    NULL,                       /* merge per-directory config structures */
    create_config,              /* create per-server config structure */
    NULL,                       /* merge per-server config structures */
    disk_cache_cmds,            /* command apr_table_t */
    disk_cache_register_hook    /* register hooks */
};