1 files changed, 414 insertions, 0 deletions

diff --git a/modules/cache/mod_file_cache.c b/modules/cache/mod_file_cache.c
new file mode 100644
index 0000000..4199361
--- /dev/null
+++ b/modules/cache/mod_file_cache.c
@@ -0,0 +1,414 @@
+/* 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.
+ */
+
+/*
+ * Author: mod_file_cache by Bill Stoddard <stoddard apache.org>
+ *         Based on mod_mmap_static by Dean Gaudet <dgaudet arctic.org>
+ *
+ * v0.01: initial implementation
+ */
+
+/*
+    Documentation:
+
+    Some sites have a set of static files that are really busy, and
+    change infrequently (or even on a regular schedule). Save time
+    by caching open handles to these files. This module, unlike
+    mod_mmap_static, caches open file handles, not file content.
+    On systems (like Windows) with heavy system call overhead and
+    that have an efficient sendfile implementation, caching file handles
+    offers several advantages over caching content. First, the file system
+    can manage the memory, allowing infrequently hit cached files to
+    be paged out. Second, since caching open handles does not consume
+    significant resources, it will be possible to enable an AutoLoadCache
+    feature where static files are dynamically loaded in the cache
+    as the server runs. On systems that have file change notification,
+    this module can be enhanced to automatically garbage collect
+    cached files that change on disk.
+
+    This module should work on Unix systems that have sendfile. Place
+    cachefile directives into your configuration to direct files to
+    be cached.
+
+        cachefile /path/to/file1
+        cachefile /path/to/file2
+        ...
+
+    These files are only cached when the server is restarted, so if you
+    change the list, or if the files are changed, then you'll need to
+    restart the server.
+
+    To reiterate that point:  if the files are modified *in place*
+    without restarting the server you may end up serving requests that
+    are completely bogus.  You should update files by unlinking the old
+    copy and putting a new copy in place.
+
+    There's no such thing as inheriting these files across vhosts or
+    whatever... place the directives in the main server only.
+
+    Known problems:
+
+    Don't use Alias or RewriteRule to move these files around...  unless
+    you feel like paying for an extra stat() on each request.  This is
+    a deficiency in the Apache API that will hopefully be solved some day.
+    The file will be served out of the file handle cache, but there will be
+    an extra stat() that's a waste.
+*/
+
+#include "apr.h"
+
+#if !(APR_HAS_SENDFILE || APR_HAS_MMAP)
+#error mod_file_cache only works on systems with APR_HAS_SENDFILE or APR_HAS_MMAP
+#endif
+
+#include "apr_mmap.h"
+#include "apr_strings.h"
+#include "apr_hash.h"
+#include "apr_buckets.h"
+
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#if APR_HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "http_protocol.h"
+#include "http_request.h"
+#include "http_core.h"
+
+module AP_MODULE_DECLARE_DATA file_cache_module;
+
+typedef struct {
+#if APR_HAS_SENDFILE
+    apr_file_t *file;
+#endif
+    const char *filename;
+    apr_finfo_t finfo;
+    int is_mmapped;
+#if APR_HAS_MMAP
+    apr_mmap_t *mm;
+#endif
+    char mtimestr[APR_RFC822_DATE_LEN];
+    char sizestr[21];   /* big enough to hold any 64-bit file size + null */
+} a_file;
+
+typedef struct {
+    apr_hash_t *fileht;
+} a_server_config;
+
+
+static void *create_server_config(apr_pool_t *p, server_rec *s)
+{
+    a_server_config *sconf = apr_palloc(p, sizeof(*sconf));
+
+    sconf->fileht = apr_hash_make(p);
+    return sconf;
+}
+
+static void cache_the_file(cmd_parms *cmd, const char *filename, int mmap)
+{
+    a_server_config *sconf;
+    a_file *new_file;
+    a_file tmp;
+    apr_file_t *fd = NULL;
+    apr_status_t rc;
+    const char *fspec;
+
+    fspec = ap_server_root_relative(cmd->pool, filename);
+    if (!fspec) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, APR_EBADPATH, cmd->server, APLOGNO(00794)
+                     "invalid file path "
+                     "%s, skipping", filename);
+        return;
+    }
+    if ((rc = apr_stat(&tmp.finfo, fspec, APR_FINFO_MIN,
+                                 cmd->temp_pool)) != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rc, cmd->server, APLOGNO(00795)
+                     "unable to stat(%s), skipping", fspec);
+        return;
+    }
+    if (tmp.finfo.filetype != APR_REG) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(00796)
+                     "%s isn't a regular file, skipping", fspec);
+        return;
+    }
+    if (tmp.finfo.size > AP_MAX_SENDFILE) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(00797)
+                     "%s is too large to cache, skipping", fspec);
+        return;
+    }
+
+    rc = apr_file_open(&fd, fspec, APR_READ | APR_BINARY | APR_XTHREAD,
+                       APR_OS_DEFAULT, cmd->pool);
+    if (rc != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rc, cmd->server, APLOGNO(00798)
+                     "unable to open(%s, O_RDONLY), skipping", fspec);
+        return;
+    }
+    apr_file_inherit_set(fd);
+
+    /* WooHoo, we have a file to put in the cache */
+    new_file = apr_pcalloc(cmd->pool, sizeof(a_file));
+    new_file->finfo = tmp.finfo;
+
+#if APR_HAS_MMAP
+    if (mmap) {
+        /* MMAPFile directive. MMAP'ing the file
+         * XXX: APR_HAS_LARGE_FILES issue; need to reject this request if
+         * size is greater than MAX(apr_size_t) (perhaps greater than 1M?).
+         */
+        if ((rc = apr_mmap_create(&new_file->mm, fd, 0,
+                                  (apr_size_t)new_file->finfo.size,
+                                  APR_MMAP_READ, cmd->pool)) != APR_SUCCESS) {
+            apr_file_close(fd);
+            ap_log_error(APLOG_MARK, APLOG_WARNING, rc, cmd->server, APLOGNO(00799)
+                         "unable to mmap %s, skipping", filename);
+            return;
+        }
+        apr_file_close(fd);
+        new_file->is_mmapped = TRUE;
+    }
+#endif
+#if APR_HAS_SENDFILE
+    if (!mmap) {
+        /* CacheFile directive. Caching the file handle */
+        new_file->is_mmapped = FALSE;
+        new_file->file = fd;
+    }
+#endif
+
+    new_file->filename = fspec;
+    apr_rfc822_date(new_file->mtimestr, new_file->finfo.mtime);
+    apr_snprintf(new_file->sizestr, sizeof new_file->sizestr, "%" APR_OFF_T_FMT, new_file->finfo.size);
+
+    sconf = ap_get_module_config(cmd->server->module_config, &file_cache_module);
+    apr_hash_set(sconf->fileht, new_file->filename, strlen(new_file->filename), new_file);
+
+}
+
+static const char *cachefilehandle(cmd_parms *cmd, void *dummy, const char *filename)
+{
+#if APR_HAS_SENDFILE
+    cache_the_file(cmd, filename, 0);
+#else
+    /* Sendfile not supported by this OS */
+    ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(00800)
+                 "unable to cache file: %s. Sendfile is not supported on this OS", filename);
+#endif
+    return NULL;
+}
+static const char *cachefilemmap(cmd_parms *cmd, void *dummy, const char *filename)
+{
+#if APR_HAS_MMAP
+    cache_the_file(cmd, filename, 1);
+#else
+    /* MMAP not supported by this OS */
+    ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(00801)
+                 "unable to cache file: %s. MMAP is not supported by this OS", filename);
+#endif
+    return NULL;
+}
+
+static int file_cache_post_config(apr_pool_t *p, apr_pool_t *plog,
+                                   apr_pool_t *ptemp, server_rec *s)
+{
+    /* Hummm, anything to do here? */
+    return OK;
+}
+
+/* If it's one of ours, fill in r->finfo now to avoid extra stat()... this is a
+ * bit of a kludge, because we really want to run after core_translate runs.
+ */
+static int file_cache_xlat(request_rec *r)
+{
+    a_server_config *sconf;
+    a_file *match;
+    int res;
+
+    sconf = ap_get_module_config(r->server->module_config, &file_cache_module);
+
+    /* we only operate when at least one cachefile directive was used */
+    if (!apr_hash_count(sconf->fileht)) {
+        return DECLINED;
+    }
+
+    res = ap_core_translate(r);
+    if (res != OK || !r->filename) {
+        return res;
+    }
+
+    /* search the cache */
+    match = (a_file *) apr_hash_get(sconf->fileht, r->filename, APR_HASH_KEY_STRING);
+    if (match == NULL)
+        return DECLINED;
+
+    /* pass search results to handler */
+    ap_set_module_config(r->request_config, &file_cache_module, match);
+
+    /* shortcircuit the get_path_info() stat() calls and stuff */
+    r->finfo = match->finfo;
+    return OK;
+}
+
+static int mmap_handler(request_rec *r, a_file *file)
+{
+#if APR_HAS_MMAP
+    conn_rec *c = r->connection;
+    apr_bucket *b;
+    apr_mmap_t *mm;
+    apr_bucket_brigade *bb = apr_brigade_create(r->pool, c->bucket_alloc);
+
+    apr_mmap_dup(&mm, file->mm, r->pool);
+    b = apr_bucket_mmap_create(mm, 0, (apr_size_t)file->finfo.size,
+                               c->bucket_alloc);
+    APR_BRIGADE_INSERT_TAIL(bb, b);
+    b = apr_bucket_eos_create(c->bucket_alloc);
+    APR_BRIGADE_INSERT_TAIL(bb, b);
+
+    if (ap_pass_brigade(r->output_filters, bb) != APR_SUCCESS)
+        return AP_FILTER_ERROR;
+#endif
+    return OK;
+}
+
+static int sendfile_handler(request_rec *r, a_file *file)
+{
+#if APR_HAS_SENDFILE
+    conn_rec *c = r->connection;
+    apr_bucket *b;
+    apr_bucket_brigade *bb = apr_brigade_create(r->pool, c->bucket_alloc);
+
+    apr_brigade_insert_file(bb, file->file, 0, file->finfo.size, r->pool);
+
+    b = apr_bucket_eos_create(c->bucket_alloc);
+    APR_BRIGADE_INSERT_TAIL(bb, b);
+
+    if (ap_pass_brigade(r->output_filters, bb) != APR_SUCCESS)
+        return AP_FILTER_ERROR;
+#endif
+    return OK;
+}
+
+static int file_cache_handler(request_rec *r)
+{
+    a_file *match;
+    int errstatus;
+    int rc = OK;
+
+    /* Bail out if r->handler isn't the default value, and doesn't look like a Content-Type
+     * XXX: Even though we made the user explicitly list each path to cache?
+     */
+    if (ap_strcmp_match(r->handler, "*/*") && !AP_IS_DEFAULT_HANDLER_NAME(r->handler)) {
+        return DECLINED;
+    }
+
+    /* we don't handle anything but GET */
+    if (r->method_number != M_GET) return DECLINED;
+
+    /* did xlat phase find the file? */
+    match = ap_get_module_config(r->request_config, &file_cache_module);
+
+    if (match == NULL) {
+        return DECLINED;
+    }
+
+    /* note that we would handle GET on this resource */
+    r->allowed |= (AP_METHOD_BIT << M_GET);
+
+    /* This handler has no use for a request body (yet), but we still
+     * need to read and discard it if the client sent one.
+     */
+    if ((errstatus = ap_discard_request_body(r)) != OK)
+        return errstatus;
+
+    ap_update_mtime(r, match->finfo.mtime);
+
+    /* ap_set_last_modified() always converts the file mtime to a string
+     * which is slow.  Accelerate the common case.
+     * ap_set_last_modified(r);
+     */
+    {
+        apr_time_t mod_time;
+        char *datestr;
+
+        mod_time = ap_rationalize_mtime(r, r->mtime);
+        if (mod_time == match->finfo.mtime)
+            datestr = match->mtimestr;
+        else {
+            datestr = apr_palloc(r->pool, APR_RFC822_DATE_LEN);
+            apr_rfc822_date(datestr, mod_time);
+        }
+        apr_table_setn(r->headers_out, "Last-Modified", datestr);
+    }
+
+    /* ap_set_content_length() always converts the same number and never
+     * returns an error.  Accelerate it.
+     */
+    r->clength = match->finfo.size;
+    apr_table_setn(r->headers_out, "Content-Length", match->sizestr);
+
+    ap_set_etag(r);
+    if ((errstatus = ap_meets_conditions(r)) != OK) {
+       return errstatus;
+    }
+
+    /* Call appropriate handler */
+    if (!r->header_only) {
+        if (match->is_mmapped == TRUE)
+            rc = mmap_handler(r, match);
+        else
+            rc = sendfile_handler(r, match);
+    }
+
+    return rc;
+}
+
+static command_rec file_cache_cmds[] =
+{
+AP_INIT_ITERATE("cachefile", cachefilehandle, NULL, RSRC_CONF,
+     "A space separated list of files to add to the file handle cache at config time"),
+AP_INIT_ITERATE("mmapfile", cachefilemmap, NULL, RSRC_CONF,
+     "A space separated list of files to mmap at config time"),
+    {NULL}
+};
+
+static void register_hooks(apr_pool_t *p)
+{
+    ap_hook_handler(file_cache_handler, NULL, NULL, APR_HOOK_LAST);
+    ap_hook_post_config(file_cache_post_config, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_translate_name(file_cache_xlat, NULL, NULL, APR_HOOK_MIDDLE);
+    /* This trick doesn't work apparently because the translate hooks
+       are single shot. If the core_hook returns OK, then our hook is
+       not called.
+    ap_hook_translate_name(file_cache_xlat, aszPre, NULL, APR_HOOK_MIDDLE);
+    */
+
+}
+
+AP_DECLARE_MODULE(file_cache) =
+{
+    STANDARD20_MODULE_STUFF,
+    NULL,                     /* create per-directory config structure */
+    NULL,                     /* merge per-directory config structures */
+    create_server_config,     /* create per-server config structure */
+    NULL,                     /* merge per-server config structures */
+    file_cache_cmds,          /* command handlers */
+    register_hooks            /* register hooks */
+};