/* 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.
*/
/*
* Apache example_hooks module. Provide demonstrations of how modules do things.
* It is not meant to be used in a production server. Since it participates
* in all of the processing phases, it could conceivable interfere with
* the proper operation of other modules -- particularly the ones related
* to security.
*
* In the interest of brevity, all functions and structures internal to
* this module, but which may have counterparts in *real* modules, are
* prefixed with 'x_' instead of 'example_'.
*
* To use mod_example_hooks, configure the Apache build with
* --enable-example-hooks and compile. Set up a <Location> block in your
* configuration file like so:
*
* <Location /example>
* SetHandler example-hooks-handler
* </Location>
*
* When you look at that location on your server, you will see a backtrace of
* the callbacks that have been invoked up to that point. See the ErrorLog for
* more information on code paths that touch mod_example_hooks.
*
* IMPORTANT NOTES
* ===============
*
* Do NOT use this module on a production server. It attaches itself to every
* phase of the server runtime operations including startup, shutdown and
* request processing, and produces copious amounts of logging data. This will
* negatively affect server performance.
*
* Do NOT use mod_example_hooks as the basis for your own code. This module
* implements every callback hook offered by the Apache core, and your
* module will almost certainly not have to implement this much. If you
* want a simple module skeleton to start development, use apxs -g.
*
* XXX TO DO XXX
* =============
*
* * Enable HTML backtrace entries for more callbacks that are not directly
* associated with a request
* * Make sure every callback that posts an HTML backtrace entry does so in the * right category, so nothing gets overwritten
* * Implement some logic to show what happens in the parent, and what in the
* child(ren)
*/
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_log.h"
#include "http_main.h"
#include "http_protocol.h"
#include "http_request.h"
#include "util_script.h"
#include "http_connection.h"
#ifdef HAVE_UNIX_SUEXEC
#include "unixd.h"
#endif
#include "scoreboard.h"
#include "mpm_common.h"
#include "apr_strings.h"
#include <stdio.h>
/*--------------------------------------------------------------------------*/
/* */
/* Data declarations. */
/* */
/* Here are the static cells and structure declarations private to our */
/* module. */
/* */
/*--------------------------------------------------------------------------*/
/*
* Sample configuration record. Used for both per-directory and per-server
* configuration data.
*
* It's perfectly reasonable to have two different structures for the two
* different environments. The same command handlers will be called for
* both, though, so the handlers need to be able to tell them apart. One
* possibility is for both structures to start with an int which is 0 for
* one and 1 for the other.
*
* Note that while the per-directory and per-server configuration records are
* available to most of the module handlers, they should be treated as
* READ-ONLY by all except the command and merge handlers. Sometimes handlers
* are handed a record that applies to the current location by implication or
* inheritance, and modifying it will change the rules for other locations.
*/
typedef struct x_cfg {
int cmode; /* Environment to which record applies
* (directory, server, or combination).
*/
#define CONFIG_MODE_SERVER 1
#define CONFIG_MODE_DIRECTORY 2
#define CONFIG_MODE_COMBO 3 /* Shouldn't ever happen. */
int local; /* Boolean: "Example" directive declared
* here?
*/
int congenital; /* Boolean: did we inherit an "Example"? */
char *trace; /* Pointer to trace string. */
char *loc; /* Location to which this record applies. */
} x_cfg;
/*
* String pointer to hold the startup trace. No harm working with a global until
* the server is (may be) multi-threaded.
*/
static const char *trace = NULL;
/*
* Declare ourselves so the configuration routines can find and know us.
* We'll fill it in at the end of the module.
*/
module AP_MODULE_DECLARE_DATA example_hooks_module;
/*--------------------------------------------------------------------------*/
/* */
/* The following pseudo-prototype declarations illustrate the parameters */
/* passed to command handlers for the different types of directive */
/* syntax. If an argument was specified in the directive definition */
/* (look for "command_rec" below), it's available to the command handler */
/* via the (void *) info field in the cmd_parms argument passed to the */
/* handler (cmd->info for the examples below). */
/* */
/*--------------------------------------------------------------------------*/
/*
* Command handler for a NO_ARGS directive. Declared in the command_rec
* list with
* AP_INIT_NO_ARGS("directive", function, mconfig, where, help)
*
* static const char *handle_NO_ARGS(cmd_parms *cmd, void *mconfig);
*/
/*
* Command handler for a RAW_ARGS directive. The "args" argument is the text
* of the commandline following the directive itself. Declared in the
* command_rec list with
* AP_INIT_RAW_ARGS("directive", function, mconfig, where, help)
*
* static const char *handle_RAW_ARGS(cmd_parms *cmd, void *mconfig,
* const char *args);
*/
/*
* Command handler for a FLAG directive. The single parameter is passed in
* "bool", which is either zero or not for Off or On respectively.
* Declared in the command_rec list with
* AP_INIT_FLAG("directive", function, mconfig, where, help)
*
* static const char *handle_FLAG(cmd_parms *cmd, void *mconfig, int bool);
*/
/*
* Command handler for a TAKE1 directive. The single parameter is passed in
* "word1". Declared in the command_rec list with
* AP_INIT_TAKE1("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE1(cmd_parms *cmd, void *mconfig,
* char *word1);
*/
/*
* Command handler for a TAKE2 directive. TAKE2 commands must always have
* exactly two arguments. Declared in the command_rec list with
* AP_INIT_TAKE2("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE2(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2);
*/
/*
* Command handler for a TAKE3 directive. Like TAKE2, these must have exactly
* three arguments, or the parser complains and doesn't bother calling us.
* Declared in the command_rec list with
* AP_INIT_TAKE3("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE3(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2, char *word3);
*/
/*
* Command handler for a TAKE12 directive. These can take either one or two
* arguments.
* - word2 is a NULL pointer if no second argument was specified.
* Declared in the command_rec list with
* AP_INIT_TAKE12("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE12(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2);
*/
/*
* Command handler for a TAKE123 directive. A TAKE123 directive can be given,
* as might be expected, one, two, or three arguments.
* - word2 is a NULL pointer if no second argument was specified.
* - word3 is a NULL pointer if no third argument was specified.
* Declared in the command_rec list with
* AP_INIT_TAKE123("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE123(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2, char *word3);
*/
/*
* Command handler for a TAKE13 directive. Either one or three arguments are
* permitted - no two-parameters-only syntax is allowed.
* - word2 and word3 are NULL pointers if only one argument was specified.
* Declared in the command_rec list with
* AP_INIT_TAKE13("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE13(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2, char *word3);
*/
/*
* Command handler for a TAKE23 directive. At least two and as many as three
* arguments must be specified.
* - word3 is a NULL pointer if no third argument was specified.
* Declared in the command_rec list with
* AP_INIT_TAKE23("directive", function, mconfig, where, help)
*
* static const char *handle_TAKE23(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2, char *word3);
*/
/*
* Command handler for a ITERATE directive.
* - Handler is called once for each of n arguments given to the directive.
* - word1 points to each argument in turn.
* Declared in the command_rec list with
* AP_INIT_ITERATE("directive", function, mconfig, where, help)
*
* static const char *handle_ITERATE(cmd_parms *cmd, void *mconfig,
* char *word1);
*/
/*
* Command handler for a ITERATE2 directive.
* - Handler is called once for each of the second and subsequent arguments
* given to the directive.
* - word1 is the same for each call for a particular directive instance (the
* first argument).
* - word2 points to each of the second and subsequent arguments in turn.
* Declared in the command_rec list with
* AP_INIT_ITERATE2("directive", function, mconfig, where, help)
*
* static const char *handle_ITERATE2(cmd_parms *cmd, void *mconfig,
* char *word1, char *word2);
*/
/*--------------------------------------------------------------------------*/
/* */
/* These routines are strictly internal to this module, and support its */
/* operation. They are not referenced by any external portion of the */
/* server. */
/* */
/*--------------------------------------------------------------------------*/
/*
* Locate our directory configuration record for the current request.
*/
static x_cfg *our_dconfig(const request_rec *r)
{
return (x_cfg *) ap_get_module_config(r->per_dir_config, &example_hooks_module);
}
/*
* The following utility routines are not used in the module. Don't
* compile them so -Wall doesn't complain about functions that are
* defined but not used.
*/
#if 0
/*
* Locate our server configuration record for the specified server.
*/
static x_cfg *our_sconfig(const server_rec *s)
{
return (x_cfg *) ap_get_module_config(s->module_config, &example_hooks_module);
}
/*
* Likewise for our configuration record for the specified request.
*/
static x_cfg *our_rconfig(const request_rec *r)
{
return (x_cfg *) ap_get_module_config(r->request_config, &example_hooks_module);
}
#endif /* if 0 */
/*
* Likewise for our configuration record for a connection.
*/
static x_cfg *our_cconfig(const conn_rec *c)
{
return (x_cfg *) ap_get_module_config(c->conn_config, &example_hooks_module);
}
/*
* You *could* change the following if you wanted to see the calling
* sequence reported in the server's error_log, but beware - almost all of
* these co-routines are called for every single request, and the impact
* on the size (and readability) of the error_log is considerable.
*/
#ifndef EXAMPLE_LOG_EACH
#define EXAMPLE_LOG_EACH 0
#endif
#if EXAMPLE_LOG_EACH
static void example_log_each(apr_pool_t *p, server_rec *s, const char *note)
{
if (s != NULL) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02991)
"mod_example_hooks: %s", note);
}
else {
apr_file_t *out = NULL;
apr_file_open_stderr(&out, p);
apr_file_printf(out, "mod_example_hooks traced in non-loggable "
"context: %s\n", note);
}
}
#endif
/*
* This utility routine traces the hooks called when the server starts up.
* It leaves a trace in a global variable, so it should not be called from
* a hook handler that runs in a multi-threaded situation.
*/
static void trace_startup(apr_pool_t *p, server_rec *s, x_cfg *mconfig,
const char *note)
{
const char *sofar;
char *where, *addon;
#if EXAMPLE_LOG_EACH
example_log_each(p, s, note);
#endif
/*
* If we weren't passed a configuration record, we can't figure out to
* what location this call applies. This only happens for co-routines
* that don't operate in a particular directory or server context. If we
* got a valid record, extract the location (directory or server) to which
* it applies.
*/
where = (mconfig != NULL) ? mconfig->loc : "nowhere";
where = (where != NULL) ? where : "";
addon = apr_pstrcat(p,
" <li>\n"
" <dl>\n"
" <dt><samp>", note, "</samp></dt>\n"
" <dd><samp>[", where, "]</samp></dd>\n"
" </dl>\n"
" </li>\n",
NULL);
/*
* Make sure that we start with a valid string, even if we have never been
* called.
*/
sofar = (trace == NULL) ? "" : trace;
trace = apr_pstrcat(p, sofar, addon, NULL);
}
/*
* This utility route traces the hooks called as a request is handled.
* It takes the current request as argument
*/
#define TRACE_NOTE "example-hooks-trace"
static void trace_request(const request_rec *r, const char *note)
{
const char *trace_copy, *sofar;
char *addon, *where;
x_cfg *cfg;
#if EXAMPLE_LOG_EACH
example_log_each(r->pool, r->server, note);
#endif
if ((sofar = apr_table_get(r->notes, TRACE_NOTE)) == NULL) {
sofar = "";
}
cfg = our_dconfig(r);
where = (cfg != NULL) ? cfg->loc : "nowhere";
where = (where != NULL) ? where : "";
addon = apr_pstrcat(r->pool,
" <li>\n"
" <dl>\n"
" <dt><samp>", note, "</samp></dt>\n"
" <dd><samp>[", where, "]</samp></dd>\n"
" </dl>\n"
" </li>\n",
NULL);
trace_copy = apr_pstrcat(r->pool, sofar, addon, NULL);
apr_table_set(r->notes, TRACE_NOTE, trace_copy);
}
/*
* This utility routine traces the hooks called while processing a
* Connection. Its trace is kept in the pool notes of the pool associated
* with the Connection.
*/
/*
* Key to get and set the userdata. We should be able to get away
* with a constant key, since in prefork mode the process will have
* the connection and its pool to itself entirely, and in
* multi-threaded mode each connection will have its own pool.
*/
#define CONN_NOTE "example-hooks-connection"
static void trace_connection(conn_rec *c, const char *note)
{
const char *trace_copy, *sofar;
char *addon, *where;
void *data;
x_cfg *cfg;
#if EXAMPLE_LOG_EACH
example_log_each(c->pool, c->base_server, note);
#endif
cfg = our_cconfig(c);
where = (cfg != NULL) ? cfg->loc : "nowhere";
where = (where != NULL) ? where : "";
addon = apr_pstrcat(c->pool,
" <li>\n"
" <dl>\n"
" <dt><samp>", note, "</samp></dt>\n"
" <dd><samp>[", where, "]</samp></dd>\n"
" </dl>\n"
" </li>\n",
NULL);
/* Find existing notes and copy */
apr_pool_userdata_get(&data, CONN_NOTE, c->pool);
sofar = (data == NULL) ? "" : (const char *) data;
/* Tack addon onto copy */
trace_copy = apr_pstrcat(c->pool, sofar, addon, NULL);
/*
* Stash copy back into pool notes. This call has a cleanup
* parameter, but we're not using it because the string has been
* allocated from that same pool. There is also an unused return
* value: we have nowhere to communicate any error that might
* occur, and will have to check for the existence of this data on
* the other end.
*/
apr_pool_userdata_set((const void *) trace_copy, CONN_NOTE,
NULL, c->pool);
}
static void trace_nocontext(apr_pool_t *p, const char *file, int line,
const char *note)
{
/*
* Since we have no request or connection to trace, or any idea
* from where this routine was called, there's really not much we
* can do. If we are not logging everything by way of the
* EXAMPLE_LOG_EACH constant, do nothing in this routine.
*/
#ifdef EXAMPLE_LOG_EACH
ap_log_perror(file, line, APLOG_MODULE_INDEX, APLOG_NOTICE, 0, p, "%s", note);
#endif
}
/*--------------------------------------------------------------------------*/
/* We prototyped the various syntax for command handlers (routines that */
/* are called when the configuration parser detects a directive declared */
/* by our module) earlier. Now we actually declare a "real" routine that */
/* will be invoked by the parser when our "real" directive is */
/* encountered. */
/* */
/* If a command handler encounters a problem processing the directive, it */
/* signals this fact by returning a non-NULL pointer to a string */
/* describing the problem. */
/* */
/* The magic return value DECLINE_CMD is used to deal with directives */
/* that might be declared by multiple modules. If the command handler */
/* returns NULL, the directive was processed; if it returns DECLINE_CMD, */
/* the next module (if any) that declares the directive is given a chance */
/* at it. If it returns any other value, it's treated as the text of an */
/* error message. */
/*--------------------------------------------------------------------------*/
/*
* Command handler for the NO_ARGS "Example" directive. All we do is mark the
* call in the trace log, and flag the applicability of the directive to the
* current location in that location's configuration record.
*/
static const char *cmd_example(cmd_parms *cmd, void *mconfig)
{
x_cfg *cfg = (x_cfg *) mconfig;
/*
* "Example Wuz Here"
*/
cfg->local = 1;
trace_startup(cmd->pool, cmd->server, cfg, "cmd_example()");
return NULL;
}
/*
* This function gets called to create a per-directory configuration
* record. This will be called for the "default" server environment, and for
* each directory for which the parser finds any of our directives applicable.
* If a directory doesn't have any of our directives involved (i.e., they
* aren't in the .htaccess file, or a <Location>, <Directory>, or related
* block), this routine will *not* be called - the configuration for the
* closest ancestor is used.
*
* The return value is a pointer to the created module-specific
* structure.
*/
static void *x_create_dir_config(apr_pool_t *p, char *dirspec)
{
x_cfg *cfg;
char *dname = dirspec;
char *note;
/*
* Allocate the space for our record from the pool supplied.
*/
cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
/*
* Now fill in the defaults. If there are any `parent' configuration
* records, they'll get merged as part of a separate callback.
*/
cfg->local = 0;
cfg->congenital = 0;
cfg->cmode = CONFIG_MODE_DIRECTORY;
/*
* Finally, add our trace to the callback list.
*/
dname = (dname != NULL) ? dname : "";
cfg->loc = apr_pstrcat(p, "DIR(", dname, ")", NULL);
note = apr_psprintf(p, "x_create_dir_config(p == %pp, dirspec == %s)",
(void*) p, dirspec);
trace_startup(p, NULL, cfg, note);
return (void *) cfg;
}
/*
* This function gets called to merge two per-directory configuration
* records. This is typically done to cope with things like .htaccess files
* or <Location> directives for directories that are beneath one for which a
* configuration record was already created. The routine has the
* responsibility of creating a new record and merging the contents of the
* other two into it appropriately. If the module doesn't declare a merge
* routine, the record for the closest ancestor location (that has one) is
* used exclusively.
*
* The routine MUST NOT modify any of its arguments!
*
* The return value is a pointer to the created module-specific structure
* containing the merged values.
*/
static void *x_merge_dir_config(apr_pool_t *p, void *parent_conf,
void *newloc_conf)
{
x_cfg *merged_config = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
x_cfg *pconf = (x_cfg *) parent_conf;
x_cfg *nconf = (x_cfg *) newloc_conf;
char *note;
/*
* Some things get copied directly from the more-specific record, rather
* than getting merged.
*/
merged_config->local = nconf->local;
merged_config->loc = apr_pstrdup(p, nconf->loc);
/*
* Others, like the setting of the `congenital' flag, get ORed in. The
* setting of that particular flag, for instance, is TRUE if it was ever
* true anywhere in the upstream configuration.
*/
merged_config->congenital = (pconf->congenital | pconf->local);
/*
* If we're merging records for two different types of environment (server
* and directory), mark the new record appropriately. Otherwise, inherit
* the current value.
*/
merged_config->cmode =
(pconf->cmode == nconf->cmode) ? pconf->cmode : CONFIG_MODE_COMBO;
/*
* Now just record our being called in the trace list. Include the
* locations we were asked to merge.
*/
note = apr_psprintf(p, "x_merge_dir_config(p == %pp, parent_conf == "
"%pp, newloc_conf == %pp)", (void*) p,
(void*) parent_conf, (void*) newloc_conf);
trace_startup(p, NULL, merged_config, note);
return (void *) merged_config;
}
/*
* This function gets called to create a per-server configuration
* record. It will always be called for the "default" server.
*
* The return value is a pointer to the created module-specific
* structure.
*/
static void *x_create_server_config(apr_pool_t *p, server_rec *s)
{
x_cfg *cfg;
char *sname = s->server_hostname;
/*
* As with the x_create_dir_config() reoutine, we allocate and fill
* in an empty record.
*/
cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
cfg->local = 0;
cfg->congenital = 0;
cfg->cmode = CONFIG_MODE_SERVER;
/*
* Note that we were called in the trace list.
*/
sname = (sname != NULL) ? sname : "";
cfg->loc = apr_pstrcat(p, "SVR(", sname, ")", NULL);
trace_startup(p, s, cfg, "x_create_server_config()");
return (void *) cfg;
}
/*
* This function gets called to merge two per-server configuration
* records. This is typically done to cope with things like virtual hosts and
* the default server configuration The routine has the responsibility of
* creating a new record and merging the contents of the other two into it
* appropriately. If the module doesn't declare a merge routine, the more
* specific existing record is used exclusively.
*
* The routine MUST NOT modify any of its arguments!
*
* The return value is a pointer to the created module-specific structure
* containing the merged values.
*/
static void *x_merge_server_config(apr_pool_t *p, void *server1_conf,
void *server2_conf)
{
x_cfg *merged_config = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
x_cfg *s1conf = (x_cfg *) server1_conf;
x_cfg *s2conf = (x_cfg *) server2_conf;
char *note;
/*
* Our inheritance rules are our own, and part of our module's semantics.
* Basically, just note whence we came.
*/
merged_config->cmode =
(s1conf->cmode == s2conf->cmode) ? s1conf->cmode : CONFIG_MODE_COMBO;
merged_config->local = s2conf->local;
merged_config->congenital = (s1conf->congenital | s1conf->local);
merged_config->loc = apr_pstrdup(p, s2conf->loc);
/*
* Trace our call, including what we were asked to merge.
*/
note = apr_pstrcat(p, "x_merge_server_config(\"", s1conf->loc, "\",\"",
s2conf->loc, "\")", NULL);
trace_startup(p, NULL, merged_config, note);
return (void *) merged_config;
}
/*--------------------------------------------------------------------------*
* *
* Now let's declare routines for each of the callback hooks in order. *
* (That's the order in which they're listed in the callback list, *not *
* the order in which the server calls them! See the command_rec *
* declaration near the bottom of this file.) Note that these may be *
* called for situations that don't relate primarily to our function - in *
* other words, the fixup handler shouldn't assume that the request has *
* to do with "example_hooks" stuff. *
* *
* With the exception of the content handler, all of our routines will be *
* called for each request, unless an earlier handler from another module *
* aborted the sequence. *
* *
* There are three types of hooks (see include/ap_config.h): *
* *
* VOID : No return code, run all handlers declared by any module *
* RUN_FIRST : Run all handlers until one returns something other *
* than DECLINED. Hook runner result is result of last callback *
* RUN_ALL : Run all handlers until one returns something other than OK *
* or DECLINED. The hook runner returns that other value. If *
* all hooks run, the hook runner returns OK. *
* *
* Handlers that are declared as "int" can return the following: *
* *
* OK Handler accepted the request and did its thing with it. *
* DECLINED Handler took no action. *
* HTTP_mumble Handler looked at request and found it wanting. *
* *
* See include/httpd.h for a list of HTTP_mumble status codes. Handlers *
* that are not declared as int return a valid pointer, or NULL if they *
* DECLINE to handle their phase for that specific request. Exceptions, if *
* any, are noted with each routine. *
*--------------------------------------------------------------------------*/
/*
* This routine is called before the server processes the configuration
* files. There is no return value.
*/
static int x_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp)
{
/*
* Log the call and exit.
*/
trace_startup(ptemp, NULL, NULL, "x_pre_config()");
return OK;
}
/*
* This routine is called after the server processes the configuration
* files. At this point the module may review and adjust its configuration
* settings in relation to one another and report any problems. On restart,
* this routine will be called twice, once in the startup process (which
* exits shortly after this phase) and once in the running server process.
*
* The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
* server will still call any remaining modules with an handler for this
* phase.
*/
static int x_check_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
/*
* Log the call and exit.
*/
trace_startup(ptemp, s, NULL, "x_check_config()");
return OK;
}
/*
* This routine is called when the -t command-line option is supplied.
* It executes only once, in the startup process, after the check_config
* phase and just before the process exits. At this point the module
* may output any information useful in configuration testing.
*
* This is a VOID hook: all defined handlers get called.
*/
static void x_test_config(apr_pool_t *pconf, server_rec *s)
{
apr_file_t *out = NULL;
apr_file_open_stderr(&out, pconf);
apr_file_printf(out, "Example module configuration test routine\n");
trace_startup(pconf, s, NULL, "x_test_config()");
}
/*
* This routine is called to perform any module-specific log file
* openings. It is invoked just before the post_config phase
*
* The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
* server will still call any remaining modules with an handler for this
* phase.
*/
static int x_open_logs(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
/*
* Log the call and exit.
*/
trace_startup(ptemp, s, NULL, "x_open_logs()");
return OK;
}
/*
* This routine is called after the server finishes the configuration
* process. At this point the module may review and adjust its configuration
* settings in relation to one another and report any problems. On restart,
* this routine will be called only once, in the running server process.
*
* The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
* server will still call any remaining modules with an handler for this
* phase.
*/
static int x_post_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
/*
* Log the call and exit.
*/
trace_startup(ptemp, s, NULL, "x_post_config()");
return OK;
}
/*
* All our process-death routine does is add its trace to the log.
*/
static apr_status_t x_child_exit(void *data)
{
char *note;
server_rec *s = data;
char *sname = s->server_hostname;
/*
* The arbitrary text we add to our trace entry indicates for which server
* we're being called.
*/
sname = (sname != NULL) ? sname : "";
note = apr_pstrcat(s->process->pool, "x_child_exit(", sname, ")", NULL);
trace_startup(s->process->pool, s, NULL, note);
return APR_SUCCESS;
}
/*
* All our process initialiser does is add its trace to the log.
*
* This is a VOID hook: all defined handlers get called.
*/
static void x_child_init(apr_pool_t *p, server_rec *s)
{
char *note;
char *sname = s->server_hostname;
/*
* The arbitrary text we add to our trace entry indicates for which server
* we're being called.
*/
sname = (sname != NULL) ? sname : "";
note = apr_pstrcat(p, "x_child_init(", sname, ")", NULL);
trace_startup(p, s, NULL, note);
apr_pool_cleanup_register(p, s, x_child_exit, x_child_exit);
}
/*
* The hook runner for ap_hook_http_scheme is aliased to ap_http_scheme(),
* a routine that the core and other modules call when they need to know
* the URL scheme for the request. For instance, mod_ssl returns "https"
* if the server_rec associated with the request has SSL enabled.
*
* This hook was named 'ap_hook_http_method' in httpd 2.0.
*
* This is a RUN_FIRST hook: the first handler to return a non NULL
* value aborts the handler chain. The http_core module inserts a
* fallback handler (with APR_HOOK_REALLY_LAST preference) that returns
* "http".
*/
static const char *x_http_scheme(const request_rec *r)
{
/*
* Log the call and exit.
*/
trace_request(r, "x_http_scheme()");
/* We have no claims to make about the request scheme */
return NULL;
}
/*
* The runner for this hook is aliased to ap_default_port(), which the
* core and other modules call when they need to know the default port
* for a particular server. This is used for instance to omit the
* port number from a Redirect response Location header URL if the port
* number is equal to the default port for the service (like 80 for http).
*
* This is a RUN_FIRST hook: the first handler to return a non-zero
* value is the last one executed. The http_core module inserts a
* fallback handler (with APR_HOOK_REALLY_LAST order specifier) that
* returns 80.
*/
static apr_port_t x_default_port(const request_rec *r)
{
/*
* Log the call and exit.
*/
trace_request(r, "x_default_port()");
return 0;
}
/*
* This routine is called just before the handler gets invoked. It allows
* a module to insert a previously defined filter into the filter chain.
*
* No filter has been defined by this module, so we just log the call
* and exit.
*
* This is a VOID hook: all defined handlers get called.
*/
static void x_insert_filter(request_rec *r)
{
/*
* Log the call and exit.
*/
trace_request(r, "x_insert_filter()");
}
/*
* This routine is called to insert a previously defined error filter into
* the filter chain as the request is being processed.
*
* For the purpose of this example, we don't have a filter to insert,
* so just add to the trace and exit.
*
* This is a VOID hook: all defined handlers get called.
*/
static void x_insert_error_filter(request_rec *r)
{
trace_request(r, "x_insert_error_filter()");
}
/*--------------------------------------------------------------------------*/
/* */
/* Now we declare our content handlers, which are invoked when the server */
/* encounters a document which our module is supposed to have a chance to */
/* see. (See mod_mime's SetHandler and AddHandler directives, and the */
/* mod_info and mod_status examples, for more details.) */
/* */
/* Since content handlers are dumping data directly into the connection */
/* (using the r*() routines, such as rputs() and rprintf()) without */
/* intervention by other parts of the server, they need to make */
/* sure any accumulated HTTP headers are sent first. This is done by */
/* calling send_http_header(). Otherwise, no header will be sent at all, */
/* and the output sent to the client will actually be HTTP-uncompliant. */
/*--------------------------------------------------------------------------*/
/*
* Sample content handler. All this does is display the call list that has
* been built up so far.
*
* This routine gets called for every request, unless another handler earlier
* in the callback chain has already handled the request. It is up to us to
* test the request_rec->handler field and see whether we are meant to handle
* this request.
*
* The content handler gets to write directly to the client using calls like
* ap_rputs() and ap_rprintf()
*
* This is a RUN_FIRST hook.
*/
static int x_handler(request_rec *r)
{
x_cfg *dcfg;
char *note;
void *conn_data;
apr_status_t status;
dcfg = our_dconfig(r);
/*
* Add our trace to the log, and whether we get to write
* content for this request.
*/
note = apr_pstrcat(r->pool, "x_handler(), handler is \"",
r->handler, "\"", NULL);
trace_request(r, note);
/* If it's not for us, get out as soon as possible. */
if (strcmp(r->handler, "example-hooks-handler")) {
return DECLINED;
}
/*
* Set the Content-type header. Note that we do not actually have to send
* the headers: this is done by the http core.
*/
ap_set_content_type(r, "text/html");
/*
* If we're only supposed to send header information (HEAD request), we're
* already there.
*/
if (r->header_only) {
return OK;
}
/*
* Now send our actual output. Since we tagged this as being
* "text/html", we need to embed any HTML.
*/
ap_rputs(DOCTYPE_HTML_3_2, r);
ap_rputs("<HTML>\n", r);
ap_rputs(" <HEAD>\n", r);
ap_rputs(" <TITLE>mod_example_hooks Module Content-Handler Output\n", r);
ap_rputs(" </TITLE>\n", r);
ap_rputs(" </HEAD>\n", r);
ap_rputs(" <BODY>\n", r);
ap_rputs(" <H1><SAMP>mod_example_hooks</SAMP> Module Content-Handler Output\n", r);
ap_rputs(" </H1>\n", r);
ap_rputs(" <P>\n", r);
ap_rprintf(r, " Apache HTTP Server version: \"%s\"\n",
ap_get_server_banner());
ap_rputs(" <BR>\n", r);
ap_rprintf(r, " Server built: \"%s\"\n", ap_get_server_built());
ap_rputs(" </P>\n", r);
ap_rputs(" <P>\n", r);
ap_rputs(" The format for the callback trace is:\n", r);
ap_rputs(" </P>\n", r);
ap_rputs(" <DL>\n", r);
ap_rputs(" <DT><EM>n</EM>.<SAMP><routine-name>", r);
ap_rputs("(<routine-data>)</SAMP>\n", r);
ap_rputs(" </DT>\n", r);
ap_rputs(" <DD><SAMP>[<applies-to>]</SAMP>\n", r);
ap_rputs(" </DD>\n", r);
ap_rputs(" </DL>\n", r);
ap_rputs(" <P>\n", r);
ap_rputs(" The <SAMP><routine-data></SAMP> is supplied by\n", r);
ap_rputs(" the routine when it requests the trace,\n", r);
ap_rputs(" and the <SAMP><applies-to></SAMP> is extracted\n", r);
ap_rputs(" from the configuration record at the time of the trace.\n", r);
ap_rputs(" <STRONG>SVR()</STRONG> indicates a server environment\n", r);
ap_rputs(" (blank means the main or default server, otherwise it's\n", r);
ap_rputs(" the name of the VirtualHost); <STRONG>DIR()</STRONG>\n", r);
ap_rputs(" indicates a location in the URL or filesystem\n", r);
ap_rputs(" namespace.\n", r);
ap_rputs(" </P>\n", r);
ap_rprintf(r, " <H2>Startup callbacks so far:</H2>\n <OL>\n%s </OL>\n",
trace);
ap_rputs(" <H2>Connection-specific callbacks so far:</H2>\n", r);
status = apr_pool_userdata_get(&conn_data, CONN_NOTE,
r->connection->pool);
if ((status == APR_SUCCESS) && conn_data) {
ap_rprintf(r, " <OL>\n%s </OL>\n", (char *) conn_data);
}
else {
ap_rputs(" <P>No connection-specific callback information was "
"retrieved.</P>\n", r);
}
ap_rputs(" <H2>Request-specific callbacks so far:</H2>\n", r);
ap_rprintf(r, " <OL>\n%s </OL>\n", apr_table_get(r->notes, TRACE_NOTE));
ap_rputs(" <H2>Environment for <EM>this</EM> call:</H2>\n", r);
ap_rputs(" <UL>\n", r);
ap_rprintf(r, " <LI>Applies-to: <SAMP>%s</SAMP>\n </LI>\n", dcfg->loc);
ap_rprintf(r, " <LI>\"Example\" directive declared here: %s\n </LI>\n",
(dcfg->local ? "YES" : "NO"));
ap_rprintf(r, " <LI>\"Example\" inherited: %s\n </LI>\n",
(dcfg->congenital ? "YES" : "NO"));
ap_rputs(" </UL>\n", r);
ap_rputs(" </BODY>\n", r);
ap_rputs("</HTML>\n", r);
/*
* We're all done, so cancel the timeout we set. Since this is probably
* the end of the request we *could* assume this would be done during
* post-processing - but it's possible that another handler might be
* called and inherit our outstanding timer. Not good; to each its own.
*/
/*
* We did what we wanted to do, so tell the rest of the server we
* succeeded.
*/
return OK;
}
/*
* The quick_handler hook presents modules with a very powerful opportunity to
* serve their content in a very early request phase. Note that this handler
* can not serve any requests from the file system because hooks like
* map_to_storage have not run. The quick_handler hook also runs before any
* authentication and access control.
*
* This hook is used by mod_cache to serve cached content.
*
* This is a RUN_FIRST hook. Return OK if you have served the request,
* DECLINED if you want processing to continue, or a HTTP_* error code to stop
* processing the request.
*/
static int x_quick_handler(request_rec *r, int lookup_uri)
{
/*
* Log the call and exit.
*/
trace_request(r, "x_quick_handler()");
return DECLINED;
}
/*
* This routine is called just after the server accepts the connection,
* but before it is handed off to a protocol module to be served. The point
* of this hook is to allow modules an opportunity to modify the connection
* as soon as possible. The core server uses this phase to setup the
* connection record based on the type of connection that is being used.
*
* This is a RUN_ALL hook.
*/
static int x_pre_connection(conn_rec *c, void *csd)
{
char *note;
/*
* Log the call and exit.
*/
note = apr_psprintf(c->pool, "x_pre_connection(c = %pp, p = %pp)",
(void*) c, (void*) c->pool);
trace_connection(c, note);
return OK;
}
/* This routine is used to actually process the connection that was received.
* Only protocol modules should implement this hook, as it gives them an
* opportunity to replace the standard HTTP processing with processing for
* some other protocol. Both echo and POP3 modules are available as
* examples.
*
* This is a RUN_FIRST hook.
*/
static int x_process_connection(conn_rec *c)
{
trace_connection(c, "x_process_connection()");
return DECLINED;
}
/*
* This routine is called after the request has been read but before any other
* phases have been processed. This allows us to make decisions based upon
* the input header fields.
*
* This is a HOOK_VOID hook.
*/
static void x_pre_read_request(request_rec *r, conn_rec *c)
{
/*
* We don't actually *do* anything here, except note the fact that we were
* called.
*/
trace_request(r, "x_pre_read_request()");
}
/*
* This routine is called after the request has been read but before any other
* phases have been processed. This allows us to make decisions based upon
* the input header fields.
*
* This is a RUN_ALL hook.
*/
static int x_post_read_request(request_rec *r)
{
/*
* We don't actually *do* anything here, except note the fact that we were
* called.
*/
trace_request(r, "x_post_read_request()");
return DECLINED;
}
/*
* This routine gives our module an opportunity to translate the URI into an
* actual filename. If we don't do anything special, the server's default
* rules (Alias directives and the like) will continue to be followed.
*
* This is a RUN_FIRST hook.
*/
static int x_translate_name(request_rec *r)
{
/*
* We don't actually *do* anything here, except note the fact that we were
* called.
*/
trace_request(r, "x_translate_name()");
return DECLINED;
}
/*
* This routine maps r->filename to a physical file on disk. Useful for
* overriding default core behavior, including skipping mapping for
* requests that are not file based.
*
* This is a RUN_FIRST hook.
*/
static int x_map_to_storage(request_rec *r)
{
/*
* We don't actually *do* anything here, except note the fact that we were
* called.
*/
trace_request(r, "x_map_to_storage()");
return DECLINED;
}
/*
* this routine gives our module another chance to examine the request
* headers and to take special action. This is the first phase whose
* hooks' configuration directives can appear inside the <Directory>
* and similar sections, because at this stage the URI has been mapped
* to the filename. For example this phase can be used to block evil
* clients, while little resources were wasted on these.
*
* This is a RUN_ALL hook.
*/
static int x_header_parser(request_rec *r)
{
/*
* We don't actually *do* anything here, except note the fact that we were
* called.
*/
trace_request(r, "x_header_parser()");
return DECLINED;
}
/*
* This routine is called to check for any module-specific restrictions placed
* upon the requested resource. (See the mod_access_compat module for an
* example.)
*
* This is a RUN_ALL hook. The first handler to return a status other than OK
* or DECLINED (for instance, HTTP_FORBIDDEN) aborts the callback chain.
*/
static int x_check_access(request_rec *r)
{
trace_request(r, "x_check_access()");
return DECLINED;
}
/*
* This routine is called to check the authentication information sent with
* the request (such as looking up the user in a database and verifying that
* the [encrypted] password sent matches the one in the database).
*
* This is a RUN_FIRST hook. The return value is OK, DECLINED, or some
* HTTP_mumble error (typically HTTP_UNAUTHORIZED).
*/
static int x_check_authn(request_rec *r)
{
/*
* Don't do anything except log the call.
*/
trace_request(r, "x_check_authn()");
return DECLINED;
}
/*
* This routine is called to check to see if the resource being requested
* requires authorisation.
*
* This is a RUN_FIRST hook. The return value is OK, DECLINED, or
* HTTP_mumble. If we return OK, no other modules are called during this
* phase.
*
* If *all* modules return DECLINED, the request is aborted with a server
* error.
*/
static int x_check_authz(request_rec *r)
{
/*
* Log the call and return OK, or access will be denied (even though we
* didn't actually do anything).
*/
trace_request(r, "x_check_authz()");
return DECLINED;
}
/*
* This routine is called to determine and/or set the various document type
* information bits, like Content-type (via r->content_type), language, et
* cetera.
*
* This is a RUN_FIRST hook.
*/
static int x_type_checker(request_rec *r)
{
/*
* Log the call, but don't do anything else - and report truthfully that
* we didn't do anything.
*/
trace_request(r, "x_type_checker()");
return DECLINED;
}
/*
* This routine is called to perform any module-specific fixing of header
* fields, et cetera. It is invoked just before any content-handler.
*
* This is a RUN_ALL HOOK.
*/
static int x_fixups(request_rec *r)
{
/*
* Log the call and exit.
*/
trace_request(r, "x_fixups()");
return DECLINED;
}
/*
* This routine is called to perform any module-specific logging activities
* over and above the normal server things.
*
* This is a RUN_ALL hook.
*/
static int x_log_transaction(request_rec *r)
{
trace_request(r, "x_log_transaction()");
return DECLINED;
}
#ifdef HAVE_UNIX_SUEXEC
/*
* This routine is called to find out under which user id to run suexec
* Unless our module runs CGI programs, there is no reason for us to
* mess with this information.
*
* This is a RUN_FIRST hook. The return value is a pointer to an
* ap_unix_identity_t or NULL.
*/
static ap_unix_identity_t *x_get_suexec_identity(const request_rec *r)
{
trace_request(r, "x_get_suexec_identity()");
return NULL;
}
#endif
/*
* This routine is called to create a connection. This hook is implemented
* by the Apache core: there is no known reason a module should override
* it.
*
* This is a RUN_FIRST hook.
*
* Return NULL to decline, a valid conn_rec pointer to accept.
*/
static conn_rec *x_create_connection(apr_pool_t *p, server_rec *server,
apr_socket_t *csd, long conn_id,
void *sbh, apr_bucket_alloc_t *alloc)
{
trace_nocontext(p, __FILE__, __LINE__, "x_create_connection()");
return NULL;
}
/*
* This hook is defined in server/core.c, but it is not actually called
* or documented.
*
* This is a RUN_ALL hook.
*/
static int x_get_mgmt_items(apr_pool_t *p, const char *val, apr_hash_t *ht)
{
/* We have nothing to do here but trace the call, and no context
* in which to trace it.
*/
trace_nocontext(p, __FILE__, __LINE__, "x_check_config()");
return DECLINED;
}
/*
* This routine gets called shortly after the request_rec structure
* is created. It provides the opportunity to manipulae the request
* at a very early stage.
*
* This is a RUN_ALL hook.
*/
static int x_create_request(request_rec *r)
{
/*
* We have a request_rec, but it is not filled in enough to give
* us a usable configuration. So, add a trace without context.
*/
trace_nocontext( r->pool, __FILE__, __LINE__, "x_create_request()");
return DECLINED;
}
/*
* This routine gets called during the startup of the MPM.
* No known existing module implements this hook.
*
* This is a RUN_ALL hook.
*/
static int x_pre_mpm(apr_pool_t *p, ap_scoreboard_e sb_type)
{
trace_nocontext(p, __FILE__, __LINE__, "x_pre_mpm()");
return DECLINED;
}
/*
* This hook gets run periodically by a maintenance function inside
* the MPM. Its exact purpose is unknown and undocumented at this time.
*
* This is a RUN_ALL hook.
*/
static int x_monitor(apr_pool_t *p, server_rec *s)
{
trace_nocontext(p, __FILE__, __LINE__, "x_monitor()");
return DECLINED;
}
/*--------------------------------------------------------------------------*/
/* */
/* Which functions are responsible for which hooks in the server. */
/* */
/*--------------------------------------------------------------------------*/
/*
* Each function our module provides to handle a particular hook is
* specified here. The functions are registered using
* ap_hook_foo(name, predecessors, successors, position)
* where foo is the name of the hook.
*
* The args are as follows:
* name -> the name of the function to call.
* predecessors -> a list of modules whose calls to this hook must be
* invoked before this module.
* successors -> a list of modules whose calls to this hook must be
* invoked after this module.
* position -> The relative position of this module. One of
* APR_HOOK_FIRST, APR_HOOK_MIDDLE, or APR_HOOK_LAST.
* Most modules will use APR_HOOK_MIDDLE. If multiple
* modules use the same relative position, Apache will
* determine which to call first.
* If your module relies on another module to run first,
* or another module running after yours, use the
* predecessors and/or successors.
*
* The number in brackets indicates the order in which the routine is called
* during request processing. Note that not all routines are necessarily
* called (such as if a resource doesn't have access restrictions).
* The actual delivery of content to the browser [9] is not handled by
* a hook; see the handler declarations below.
*/
static void x_register_hooks(apr_pool_t *p)
{
ap_hook_pre_config(x_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_check_config(x_check_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_test_config(x_test_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_open_logs(x_open_logs, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_post_config(x_post_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_child_init(x_child_init, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_handler(x_handler, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_quick_handler(x_quick_handler, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_pre_connection(x_pre_connection, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_process_connection(x_process_connection, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_pre_read_request(x_pre_read_request, NULL, NULL,
APR_HOOK_MIDDLE);
/* [1] post read_request handling */
ap_hook_post_read_request(x_post_read_request, NULL, NULL,
APR_HOOK_MIDDLE);
ap_hook_log_transaction(x_log_transaction, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_http_scheme(x_http_scheme, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_default_port(x_default_port, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_translate_name(x_translate_name, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_map_to_storage(x_map_to_storage, NULL,NULL, APR_HOOK_MIDDLE);
ap_hook_header_parser(x_header_parser, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_fixups(x_fixups, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_type_checker(x_type_checker, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_check_access(x_check_access, NULL, NULL, APR_HOOK_MIDDLE,
AP_AUTH_INTERNAL_PER_CONF);
ap_hook_check_authn(x_check_authn, NULL, NULL, APR_HOOK_MIDDLE,
AP_AUTH_INTERNAL_PER_CONF);
ap_hook_check_authz(x_check_authz, NULL, NULL, APR_HOOK_MIDDLE,
AP_AUTH_INTERNAL_PER_CONF);
ap_hook_insert_filter(x_insert_filter, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_insert_error_filter(x_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
#ifdef HAVE_UNIX_SUEXEC
ap_hook_get_suexec_identity(x_get_suexec_identity, NULL, NULL, APR_HOOK_MIDDLE);
#endif
ap_hook_create_connection(x_create_connection, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_get_mgmt_items(x_get_mgmt_items, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_create_request(x_create_request, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_pre_mpm(x_pre_mpm, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_monitor(x_monitor, NULL, NULL, APR_HOOK_MIDDLE);
}
/*--------------------------------------------------------------------------*/
/* */
/* All of the routines have been declared now. Here's the list of */
/* directives specific to our module, and information about where they */
/* may appear and how the command parser should pass them to us for */
/* processing. Note that care must be taken to ensure that there are NO */
/* collisions of directive names between modules. */
/* */
/*--------------------------------------------------------------------------*/
/*
* List of directives specific to our module.
*/
static const command_rec x_cmds[] =
{
AP_INIT_NO_ARGS(
"Example", /* directive name */
cmd_example, /* config action routine */
NULL, /* argument to include in call */
OR_OPTIONS, /* where available */
"Example directive - no arguments" /* directive description */
),
{NULL}
};
/*--------------------------------------------------------------------------*/
/* */
/* Finally, the list of callback routines and data structures that provide */
/* the static hooks into our module from the other parts of the server. */
/* */
/*--------------------------------------------------------------------------*/
/*
* Module definition for configuration. If a particular callback is not
* needed, replace its routine name below with the word NULL.
*/
AP_DECLARE_MODULE(example_hooks) =
{
STANDARD20_MODULE_STUFF,
x_create_dir_config, /* per-directory config creator */
x_merge_dir_config, /* dir config merger */
x_create_server_config, /* server config creator */
x_merge_server_config, /* server config merger */
x_cmds, /* command table */
x_register_hooks, /* set up other request processing hooks */
};