/* 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 "apr_lib.h"

#include "apr_file_io.h"

#include "apr_strings.h"

#include "mod_cache.h"

#include "mod_cache_disk.h"

#include "http_config.h"

#include "http_log.h"

#include "http_core.h"

#include "ap_provider.h"

#include "util_filter.h"

#include "util_script.h"

#include "util_charset.h"

/*

 * mod_cache_disk: Disk Based HTTP 1.1 Cache.

 *

 * Flow to Find the .data file:

 *   Incoming client requests URI /foo/bar/baz

 *   Generate <hash> off of /foo/bar/baz

 *   Open <hash>.header

 *   Read in <hash>.header file (may contain Format #1 or Format #2)

 *   If format #1 (Contains a list of Vary Headers):

 *      Use each header name (from .header) with our request values (headers_in) to

 *      regenerate <hash> using HeaderName+HeaderValue+.../foo/bar/baz

 *      re-read in <hash>.header (must be format #2)

 *   read in <hash>.data

 *

 * Format #1:

 *   apr_uint32_t format;

 *   apr_time_t expire;

 *   apr_array_t vary_headers (delimited by CRLF)

 *

 * Format #2:

 *   disk_cache_info_t (first sizeof(apr_uint32_t) bytes is the format)

 *   entity name (dobj->name) [length is in disk_cache_info_t->name_len]

 *   r->headers_out (delimited by CRLF)

 *   CRLF

 *   r->headers_in (delimited by CRLF)

 *   CRLF

 */

module AP_MODULE_DECLARE_DATA cache_disk_module;

/* Forward declarations */

static int remove_entity(cache_handle_t *h);

static apr_status_t store_headers(cache_handle_t *h, request_rec *r, cache_info *i);

static apr_status_t store_body(cache_handle_t *h, request_rec *r, apr_bucket_brigade *in,

                               apr_bucket_brigade *out);

static apr_status_t recall_headers(cache_handle_t *h, request_rec *r);

static apr_status_t recall_body(cache_handle_t *h, apr_pool_t *p, apr_bucket_brigade *bb);

static apr_status_t read_array(request_rec *r, apr_array_header_t* arr,

                               apr_file_t *file);

/*

 * Local static functions

 */

static char *header_file(apr_pool_t *p, disk_cache_conf *conf,

                         disk_cache_object_t *dobj, const char *name)

{

    if (!dobj->hashfile) {

        dobj->hashfile = ap_cache_generate_name(p, conf->dirlevels,

                                                conf->dirlength, name);

    }

    if (dobj->prefix) {

        return apr_pstrcat(p, dobj->prefix, CACHE_VDIR_SUFFIX "/",

                           dobj->hashfile, CACHE_HEADER_SUFFIX, NULL);

     }

     else {

        return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,

                           CACHE_HEADER_SUFFIX, NULL);

     }

}

static char *data_file(apr_pool_t *p, disk_cache_conf *conf,

                       disk_cache_object_t *dobj, const char *name)

{

    if (!dobj->hashfile) {

        dobj->hashfile = ap_cache_generate_name(p, conf->dirlevels,

                                                conf->dirlength, name);

    }

    if (dobj->prefix) {

        return apr_pstrcat(p, dobj->prefix, CACHE_VDIR_SUFFIX "/",

                           dobj->hashfile, CACHE_DATA_SUFFIX, NULL);

     }

     else {

        return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,

                           CACHE_DATA_SUFFIX, NULL);

     }

}

static apr_status_t mkdir_structure(disk_cache_conf *conf, const char *file, apr_pool_t *pool)

{

    apr_status_t rv;

    char *p;

    for (p = (char*)file + conf->cache_root_len + 1;;) {

        p = strchr(p, '/');

        if (!p)

            break;

        *p = '\0';

        rv = apr_dir_make(file,

                          APR_UREAD|APR_UWRITE|APR_UEXECUTE, pool);

        if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {

            return rv;

        }

        *p = '/';

        ++p;

    }

    return APR_SUCCESS;

}

/* htcacheclean may remove directories underneath us.

 * So, we'll try renaming three times at a cost of 0.002 seconds.

 */

static apr_status_t safe_file_rename(disk_cache_conf *conf,

                                     const char *src, const char *dest,

                                     apr_pool_t *pool)

{

    apr_status_t rv;

    rv = apr_file_rename(src, dest, pool);

    if (rv != APR_SUCCESS) {

        int i;

        for (i = 0; i < 2 && rv != APR_SUCCESS; i++) {

            /* 1000 micro-seconds aka 0.001 seconds. */

            apr_sleep(1000);

            rv = mkdir_structure(conf, dest, pool);

            if (rv != APR_SUCCESS)

                continue;

            rv = apr_file_rename(src, dest, pool);

        }

    }

    return rv;

}

static apr_status_t file_cache_el_final(disk_cache_conf *conf, disk_cache_file_t *file,

                                        request_rec *r)

{

    apr_status_t rv = APR_SUCCESS;

    /* This assumes that the tempfiles are on the same file system

     * as the cache_root. If not, then we need a file copy/move

     * rather than a rename.

     */

    /* move the file over */

    if (file->tempfd) {

        rv = safe_file_rename(conf, file->tempfile, file->file, file->pool);

        if (rv != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_WARNING, rv, r, APLOGNO(00699)

                    "rename tempfile to file failed:"

                    " %s -> %s", file->tempfile, file->file);

            apr_file_remove(file->tempfile, file->pool);

        }

        file->tempfd = NULL;

    }

    return rv;

}

static apr_status_t file_cache_temp_cleanup(void *dummy)

{

    disk_cache_file_t *file = (disk_cache_file_t *)dummy;

    /* clean up the temporary file */

    if (file->tempfd) {

        apr_file_remove(file->tempfile, file->pool);

        file->tempfd = NULL;

    }

    file->tempfile = NULL;

    file->pool = NULL;

    return APR_SUCCESS;

}

static apr_status_t file_cache_create(disk_cache_conf *conf, disk_cache_file_t *file,

                                      apr_pool_t *pool)

{

    file->pool = pool;

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

    apr_pool_cleanup_register(pool, file, file_cache_temp_cleanup, apr_pool_cleanup_null);

    return APR_SUCCESS;

}

/* These two functions get and put state information into the data

 * file for an ap_cache_el, this state information will be read

 * and written transparent to clients of this module

 */

static int file_cache_recall_mydata(apr_file_t *fd, cache_info *info,

                                    disk_cache_object_t *dobj, request_rec *r)

{

    apr_status_t rv;

    char *urlbuff;

    apr_size_t len;

    /* read the data from the cache file */

    len = sizeof(disk_cache_info_t);

    rv = apr_file_read_full(fd, &dobj->disk_info, len, &len;;

    if (rv != APR_SUCCESS) {

        return rv;

    }

    /* Store it away so we can get it later. */

    info->status = dobj->disk_info.status;

    info->date = dobj->disk_info.date;

    info->expire = dobj->disk_info.expire;

    info->request_time = dobj->disk_info.request_time;

    info->response_time = dobj->disk_info.response_time;

    memcpy(&info->control, &dobj->disk_info.control, sizeof(cache_control_t));

    /* Note that we could optimize this by conditionally doing the palloc

     * depending upon the size. */

    urlbuff = apr_palloc(r->pool, dobj->disk_info.name_len + 1);

    len = dobj->disk_info.name_len;

    rv = apr_file_read_full(fd, urlbuff, len, &len;;

    if (rv != APR_SUCCESS) {

        return rv;

    }

    urlbuff[dobj->disk_info.name_len] = '\0';

    /* check that we have the same URL */

    /* Would strncmp be correct? */

    if (strcmp(urlbuff, dobj->name) != 0) {

        return APR_EGENERAL;

    }

    return APR_SUCCESS;

}

static const char* regen_key(apr_pool_t *p, apr_table_t *headers,

                             apr_array_header_t *varray, const char *oldkey)

{

    struct iovec *iov;

    int i, k;

    int nvec;

    const char *header;

    const char **elts;

    nvec = (varray->nelts * 2) + 1;

    iov = apr_palloc(p, sizeof(struct iovec) * nvec);

    elts = (const char **) varray->elts;

    /* TODO:

     *    - Handle multiple-value headers better. (sort them?)

     *    - Handle Case in-sensitive Values better.

     *        This isn't the end of the world, since it just lowers the cache

     *        hit rate, but it would be nice to fix.

     *

     * The majority are case insenstive if they are values (encoding etc).

     * Most of rfc2616 is case insensitive on header contents.

     *

     * So the better solution may be to identify headers which should be

     * treated case-sensitive?

     *  HTTP URI's (3.2.3) [host and scheme are insensitive]

     *  HTTP method (5.1.1)

     *  HTTP-date values (3.3.1)

     *  3.7 Media Types [exerpt]

     *     The type, subtype, and parameter attribute names are case-

     *     insensitive. Parameter values might or might not be case-sensitive,

     *     depending on the semantics of the parameter name.

     *  4.20 Except [exerpt]

     *     Comparison of expectation values is case-insensitive for unquoted

     *     tokens (including the 100-continue token), and is case-sensitive for

     *     quoted-string expectation-extensions.

     */

    for (i=0, k=0; i < varray->nelts; i++) {

        header = apr_table_get(headers, elts[i]);

        if (!header) {

            header = "";

        }

        iov[k].iov_base = (char*) elts[i];

        iov[k].iov_len = strlen(elts[i]);

        k++;

        iov[k].iov_base = (char*) header;

        iov[k].iov_len = strlen(header);

        k++;

    }

    iov[k].iov_base = (char*) oldkey;

    iov[k].iov_len = strlen(oldkey);

    k++;

    return apr_pstrcatv(p, iov, k, NULL);

}

static int array_alphasort(const void *fn1, const void *fn2)

{

    return strcmp(*(char**)fn1, *(char**)fn2);

}

static void tokens_to_array(apr_pool_t *p, const char *data,

                            apr_array_header_t *arr)

{

    char *token;

    while ((token = ap_get_list_item(p, &data)) != NULL) {

        *((const char **) apr_array_push(arr)) = token;

    }

    /* Sort it so that "Vary: A, B" and "Vary: B, A" are stored the same. */

    qsort((void *) arr->elts, arr->nelts,

         sizeof(char *), array_alphasort);

}

/*

 * Hook and mod_cache callback functions

 */

static int create_entity(cache_handle_t *h, request_rec *r, const char *key, apr_off_t len,

                         apr_bucket_brigade *bb)

{

    disk_cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_disk_module);

    disk_cache_conf *conf = ap_get_module_config(r->server->module_config,

                                                 &cache_disk_module);

    cache_object_t *obj;

    disk_cache_object_t *dobj;

    apr_pool_t *pool;

    if (conf->cache_root == NULL) {

        return DECLINED;

    }

    /* we don't support caching of range requests (yet) */

    if (r->status == HTTP_PARTIAL_CONTENT) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00700)

                "URL %s partial content response not cached",

                key);

        return DECLINED;

    }

    /* Note, len is -1 if unknown so don't trust it too hard */

    if (len > dconf->maxfs) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00701)

                "URL %s failed the size check "

                "(%" APR_OFF_T_FMT " > %" APR_OFF_T_FMT ")",

                key, len, dconf->maxfs);

        return DECLINED;

    }

    if (len >= 0 && len < dconf->minfs) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00702)

                "URL %s failed the size check "

                "(%" APR_OFF_T_FMT " < %" APR_OFF_T_FMT ")",

                key, len, dconf->minfs);

        return DECLINED;

    }

    /* Allocate and initialize cache_object_t and disk_cache_object_t */

    h->cache_obj = obj = apr_pcalloc(r->pool, sizeof(*obj));

    obj->vobj = dobj = apr_pcalloc(r->pool, sizeof(*dobj));

    obj->key = apr_pstrdup(r->pool, key);

    dobj->name = obj->key;

    dobj->prefix = NULL;

    /* Save the cache root */

    dobj->root = apr_pstrmemdup(r->pool, conf->cache_root, conf->cache_root_len);

    dobj->root_len = conf->cache_root_len;

    apr_pool_create(&pool, r->pool);

    apr_pool_tag(pool, "mod_cache (create_entity)");

    file_cache_create(conf, &dobj->hdrs, pool);

    file_cache_create(conf, &dobj->vary, pool);

    file_cache_create(conf, &dobj->data, pool);

    dobj->data.file = data_file(r->pool, conf, dobj, key);

    dobj->hdrs.file = header_file(r->pool, conf, dobj, key);

    dobj->vary.file = header_file(r->pool, conf, dobj, key);

    dobj->disk_info.header_only = r->header_only;

    return OK;

}

static int open_entity(cache_handle_t *h, request_rec *r, const char *key)

{

    apr_uint32_t format;

    apr_size_t len;

    const char *nkey;

    apr_status_t rc;

    static int error_logged = 0;

    disk_cache_conf *conf = ap_get_module_config(r->server->module_config,

                                                 &cache_disk_module);

#ifdef APR_SENDFILE_ENABLED

    core_dir_config *coreconf = ap_get_core_module_config(r->per_dir_config);

#endif

    apr_finfo_t finfo;

    cache_object_t *obj;

    cache_info *info;

    disk_cache_object_t *dobj;

    int flags;

    apr_pool_t *pool;

    h->cache_obj = NULL;

    /* Look up entity keyed to 'url' */

    if (conf->cache_root == NULL) {

        if (!error_logged) {

            error_logged = 1;

            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00703)

                    "Cannot cache files to disk without a CacheRoot specified.");

        }

        return DECLINED;

    }

    /* Create and init the cache object */

    obj = apr_pcalloc(r->pool, sizeof(cache_object_t));

    dobj = apr_pcalloc(r->pool, sizeof(disk_cache_object_t));

    info = &(obj->info);

    /* Open the headers file */

    dobj->prefix = NULL;

    /* Save the cache root */

    dobj->root = apr_pstrmemdup(r->pool, conf->cache_root, conf->cache_root_len);

    dobj->root_len = conf->cache_root_len;

    dobj->vary.file = header_file(r->pool, conf, dobj, key);

    flags = APR_READ|APR_BINARY|APR_BUFFERED;

    rc = apr_file_open(&dobj->vary.fd, dobj->vary.file, flags, 0, r->pool);

    if (rc != APR_SUCCESS) {

        return DECLINED;

    }

    /* read the format from the cache file */

    len = sizeof(format);

    apr_file_read_full(dobj->vary.fd, &format, len, &len;;

    if (format == VARY_FORMAT_VERSION) {

        apr_array_header_t* varray;

        apr_time_t expire;

        len = sizeof(expire);

        apr_file_read_full(dobj->vary.fd, &expire, len, &len;;

        varray = apr_array_make(r->pool, 5, sizeof(char*));

        rc = read_array(r, varray, dobj->vary.fd);

        if (rc != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_ERR, rc, r, APLOGNO(00704)

                    "Cannot parse vary header file: %s",

                    dobj->vary.file);

            apr_file_close(dobj->vary.fd);

            return DECLINED;

        }

        apr_file_close(dobj->vary.fd);

        nkey = regen_key(r->pool, r->headers_in, varray, key);

        dobj->hashfile = NULL;

        dobj->prefix = dobj->vary.file;

        dobj->hdrs.file = header_file(r->pool, conf, dobj, nkey);

        flags = APR_READ|APR_BINARY|APR_BUFFERED;

        rc = apr_file_open(&dobj->hdrs.fd, dobj->hdrs.file, flags, 0, r->pool);

        if (rc != APR_SUCCESS) {

            return DECLINED;

        }

    }

    else if (format != DISK_FORMAT_VERSION) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00705)

                "File '%s' has a version mismatch. File had version: %d.",

                dobj->vary.file, format);

        apr_file_close(dobj->vary.fd);

        return DECLINED;

    }

    else {

        apr_off_t offset = 0;

        /* oops, not vary as it turns out */

        dobj->hdrs.fd = dobj->vary.fd;

        dobj->vary.fd = NULL;

        dobj->hdrs.file = dobj->vary.file;

        /* This wasn't a Vary Format file, so we must seek to the

         * start of the file again, so that later reads work.

         */

        apr_file_seek(dobj->hdrs.fd, APR_SET, &offset);

        nkey = key;

    }

    obj->key = nkey;

    dobj->key = nkey;

    dobj->name = key;

    apr_pool_create(&pool, r->pool);

    apr_pool_tag(pool, "mod_cache (open_entity)");

    file_cache_create(conf, &dobj->hdrs, pool);

    file_cache_create(conf, &dobj->vary, pool);

    file_cache_create(conf, &dobj->data, pool);

    dobj->data.file = data_file(r->pool, conf, dobj, nkey);

    /* Read the bytes to setup the cache_info fields */

    rc = file_cache_recall_mydata(dobj->hdrs.fd, info, dobj, r);

    if (rc != APR_SUCCESS) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, rc, r, APLOGNO(00706)

                "Cannot read header file %s", dobj->hdrs.file);

        apr_file_close(dobj->hdrs.fd);

        return DECLINED;

    }

    /* Is this a cached HEAD request? */

    if (dobj->disk_info.header_only && !r->header_only) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00707)

                "HEAD request cached, non-HEAD requested, ignoring: %s",

                dobj->hdrs.file);

        apr_file_close(dobj->hdrs.fd);

        return DECLINED;

    }

    /* Open the data file */

    if (dobj->disk_info.has_body) {

        flags = APR_READ | APR_BINARY;

#ifdef APR_SENDFILE_ENABLED

        /* When we are in the quick handler we don't have the per-directory

         * configuration, so this check only takes the global setting of

         * the EnableSendFile directive into account.

         */

        flags |= AP_SENDFILE_ENABLED(coreconf->enable_sendfile);

#endif

        rc = apr_file_open(&dobj->data.fd, dobj->data.file, flags, 0, r->pool);

        if (rc != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_ERR, rc, r, APLOGNO(00708)

                    "Cannot open data file %s", dobj->data.file);

            apr_file_close(dobj->hdrs.fd);

            return DECLINED;

        }

        rc = apr_file_info_get(&finfo, APR_FINFO_SIZE | APR_FINFO_IDENT,

                dobj->data.fd);

        if (rc == APR_SUCCESS) {

            dobj->file_size = finfo.size;

        }

        /* Atomic check - does the body file belong to the header file? */

        if (dobj->disk_info.inode == finfo.inode &&

                dobj->disk_info.device == finfo.device) {

            /* Initialize the cache_handle callback functions */

            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00709)

                    "Recalled cached URL info header %s", dobj->name);

            /* make the configuration stick */

            h->cache_obj = obj;

            obj->vobj = dobj;

            return OK;

        }

    }

    else {

        /* make the configuration stick */

        h->cache_obj = obj;

        obj->vobj = dobj;

        return OK;

    }

    /* Oh dear, no luck matching header to the body */

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00710)

            "Cached URL info header '%s' didn't match body, ignoring this entry",

            dobj->name);

    apr_file_close(dobj->hdrs.fd);

    return DECLINED;

}

static void close_disk_cache_fd(disk_cache_file_t *file)

{

   if (file->fd != NULL) {

       apr_file_close(file->fd);

       file->fd = NULL;

   }

   if (file->tempfd != NULL) {

       apr_file_close(file->tempfd);

       file->tempfd = NULL;

   }

}

static int remove_entity(cache_handle_t *h)

{

    disk_cache_object_t *dobj = (disk_cache_object_t *) h->cache_obj->vobj;

    close_disk_cache_fd(&(dobj->hdrs));

    close_disk_cache_fd(&(dobj->vary));

    close_disk_cache_fd(&(dobj->data));

    /* Null out the cache object pointer so next time we start from scratch  */

    h->cache_obj = NULL;

    return OK;

}

static int remove_url(cache_handle_t *h, request_rec *r)

{

    apr_status_t rc;

    disk_cache_object_t *dobj;

    /* Get disk cache object from cache handle */

    dobj = (disk_cache_object_t *) h->cache_obj->vobj;

    if (!dobj) {

        return DECLINED;

    }

    /* Delete headers file */

    if (dobj->hdrs.file) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00711)

                "Deleting %s from cache.", dobj->hdrs.file);

        rc = apr_file_remove(dobj->hdrs.file, r->pool);

        if ((rc != APR_SUCCESS) && !APR_STATUS_IS_ENOENT(rc)) {

            /* Will only result in an output if httpd is started with -e debug.

             * For reason see log_error_core for the case s == NULL.

             */

            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rc, r, APLOGNO(00712)

                    "Failed to delete headers file %s from cache.",

                    dobj->hdrs.file);

            return DECLINED;

        }

    }

    /* Delete data file */

    if (dobj->data.file) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00713)

                "Deleting %s from cache.", dobj->data.file);

        rc = apr_file_remove(dobj->data.file, r->pool);

        if ((rc != APR_SUCCESS) && !APR_STATUS_IS_ENOENT(rc)) {

            /* Will only result in an output if httpd is started with -e debug.

             * For reason see log_error_core for the case s == NULL.

             */

            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rc, r, APLOGNO(00714)

                    "Failed to delete data file %s from cache.",

                    dobj->data.file);

            return DECLINED;

        }

    }

    /* now delete directories as far as possible up to our cache root */

    if (dobj->root) {

        const char *str_to_copy;

        str_to_copy = dobj->hdrs.file ? dobj->hdrs.file : dobj->data.file;

        if (str_to_copy) {

            char *dir, *slash, *q;

            dir = apr_pstrdup(r->pool, str_to_copy);

            /* remove filename */

            slash = strrchr(dir, '/');

            *slash = '\0';

            /*

             * now walk our way back to the cache root, delete everything

             * in the way as far as possible

             *

             * Note: due to the way we constructed the file names in

             * header_file and data_file, we are guaranteed that the

             * cache_root is suffixed by at least one '/' which will be

             * turned into a terminating null by this loop.  Therefore,

             * we won't either delete or go above our cache root.

             */

            for (q = dir + dobj->root_len; *q ; ) {

                 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00715)

                        "Deleting directory %s from cache", dir);

                 rc = apr_dir_remove(dir, r->pool);

                 if (rc != APR_SUCCESS && !APR_STATUS_IS_ENOENT(rc)) {

                    break;

                 }

                 slash = strrchr(q, '/');

                 *slash = '\0';

            }

        }

    }

    return OK;

}

static apr_status_t read_array(request_rec *r, apr_array_header_t* arr,

                               apr_file_t *file)

{

    char w[MAX_STRING_LEN];

    int p;

    apr_status_t rv;

    while (1) {

        rv = apr_file_gets(w, MAX_STRING_LEN - 1, file);

        if (rv != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00716)

                          "Premature end of vary array.");

            return rv;

        }

        p = strlen(w);

        if (p > 0 && w[p - 1] == '\n') {

            if (p > 1 && w[p - 2] == CR) {

                w[p - 2] = '\0';

            }

            else {

                w[p - 1] = '\0';

            }

        }

        /* If we've finished reading the array, break out of the loop. */

        if (w[0] == '\0') {

            break;

        }

        *((const char **) apr_array_push(arr)) = apr_pstrdup(r->pool, w);

    }

    return APR_SUCCESS;

}

static apr_status_t store_array(apr_file_t *fd, apr_array_header_t* arr)

{

    int i;

    apr_status_t rv;

    struct iovec iov[2];

    apr_size_t amt;

    const char **elts;

    elts = (const char **) arr->elts;

    for (i = 0; i < arr->nelts; i++) {

        iov[0].iov_base = (char*) elts[i];

        iov[0].iov_len = strlen(elts[i]);

        iov[1].iov_base = CRLF;

        iov[1].iov_len = sizeof(CRLF) - 1;

        rv = apr_file_writev_full(fd, (const struct iovec *) &iov, 2, &amt;;

        if (rv != APR_SUCCESS) {

            return rv;

        }

    }

    iov[0].iov_base = CRLF;

    iov[0].iov_len = sizeof(CRLF) - 1;

    return apr_file_writev_full(fd, (const struct iovec *) &iov, 1, &amt;;

}

static apr_status_t read_table(cache_handle_t *handle, request_rec *r,

                               apr_table_t *table, apr_file_t *file)

{

    char w[MAX_STRING_LEN];

    char *l;

    int p;

    apr_status_t rv;

    while (1) {

        /* ### What about APR_EOF? */

        rv = apr_file_gets(w, MAX_STRING_LEN - 1, file);

        if (rv != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00717)

                          "Premature end of cache headers.");

            return rv;

        }

        /* Delete terminal (CR?)LF */

        p = strlen(w);

        /* Indeed, the host's '\n':

           '\012' for UNIX; '\015' for MacOS; '\025' for OS/390

           -- whatever the script generates.

        */

        if (p > 0 && w[p - 1] == '\n') {

            if (p > 1 && w[p - 2] == CR) {

                w[p - 2] = '\0';

            }

            else {

                w[p - 1] = '\0';

            }

        }

        /* If we've finished reading the headers, break out of the loop. */

        if (w[0] == '\0') {

            break;

        }

#if APR_CHARSET_EBCDIC

        /* Chances are that we received an ASCII header text instead of

         * the expected EBCDIC header lines. Try to auto-detect:

         */

        if (!(l = strchr(w, ':'))) {

            int maybeASCII = 0, maybeEBCDIC = 0;

            unsigned char *cp, native;

            apr_size_t inbytes_left, outbytes_left;

            for (cp = w; *cp != '\0'; ++cp) {

                native = apr_xlate_conv_byte(ap_hdrs_from_ascii, *cp);

                if (apr_isprint(*cp) && !apr_isprint(native))

                    ++maybeEBCDIC;

                if (!apr_isprint(*cp) && apr_isprint(native))

                    ++maybeASCII;

            }

            if (maybeASCII > maybeEBCDIC) {

                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00718)

                        "CGI Interface Error: Script headers apparently ASCII: (CGI = %s)",

                        r->filename);

                inbytes_left = outbytes_left = cp - w;

                apr_xlate_conv_buffer(ap_hdrs_from_ascii,

                                      w, &inbytes_left, w, &outbytes_left);

            }

        }

#endif /*APR_CHARSET_EBCDIC*/

        /* if we see a bogus header don't ignore it. Shout and scream */

        if (!(l = strchr(w, ':'))) {

            return APR_EGENERAL;

        }

        *l++ = '\0';

        while (apr_isspace(*l)) {

            ++l;

        }

        apr_table_add(table, w, l);

    }

    return APR_SUCCESS;

}

/*

 * Reads headers from a buffer and returns an array of headers.

 * Returns NULL on file error

 * This routine tries to deal with too long lines and continuation lines.

 * @@@: XXX: FIXME: currently the headers are passed thru un-merged.

 * Is that okay, or should they be collapsed where possible?

 */

static apr_status_t recall_headers(cache_handle_t *h, request_rec *r)

{

    disk_cache_object_t *dobj = (disk_cache_object_t *) h->cache_obj->vobj;

    apr_status_t rv;

    /* This case should not happen... */

    if (!dobj->hdrs.fd) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00719)

                "recalling headers; but no header fd for %s", dobj->name);

        return APR_NOTFOUND;

    }

    h->req_hdrs = apr_table_make(r->pool, 20);

    h->resp_hdrs = apr_table_make(r->pool, 20);

    /* Call routine to read the header lines/status line */