config.c

/* 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.
 */

/*
 * http_config.c: once was auxiliary functions for reading httpd's config
 * file and converting filenames into a namespace
 *
 * Rob McCool
 *
 * Wall-to-wall rewrite for Apache... commands which are part of the
 * server core can now be found next door in "http_core.c".  Now contains
 * general command loop, and functions which do bookkeeping for the new
 * Apache config stuff (modules and configuration vectors).
 *
 * rst
 *
 */

#include "apr.h"
#include "apr_strings.h"
#include "apr_portable.h"
#include "apr_file_io.h"
#include "apr_fnmatch.h"

#define APR_WANT_STDIO
#define APR_WANT_STRFUNC
#include "apr_want.h"

#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_protocol.h"
#include "http_core.h"
#include "http_log.h"      /* for errors in parse_htaccess */
#include "http_request.h"  /* for default_handler (see invoke_handler) */
#include "http_main.h"
#include "http_vhost.h"
#include "util_cfgtree.h"
#include "util_varbuf.h"
#include "mpm_common.h"

#define APLOG_UNSET   (APLOG_NO_MODULE - 1)
/* we know core's module_index is 0 */
#undef APLOG_MODULE_INDEX
#define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX

AP_DECLARE_DATA const char *ap_server_argv0 = NULL;
AP_DECLARE_DATA const char *ap_server_root = NULL;
AP_DECLARE_DATA const char *ap_runtime_dir = NULL;
AP_DECLARE_DATA server_rec *ap_server_conf = NULL;
AP_DECLARE_DATA apr_pool_t *ap_pglobal = NULL;

AP_DECLARE_DATA apr_array_header_t *ap_server_pre_read_config = NULL;
AP_DECLARE_DATA apr_array_header_t *ap_server_post_read_config = NULL;
AP_DECLARE_DATA apr_array_header_t *ap_server_config_defines = NULL;

AP_DECLARE_DATA ap_directive_t *ap_conftree = NULL;

APR_HOOK_STRUCT(
           APR_HOOK_LINK(header_parser)
           APR_HOOK_LINK(pre_config)
           APR_HOOK_LINK(check_config)
           APR_HOOK_LINK(post_config)
           APR_HOOK_LINK(open_logs)
           APR_HOOK_LINK(child_init)
           APR_HOOK_LINK(handler)
           APR_HOOK_LINK(quick_handler)
           APR_HOOK_LINK(optional_fn_retrieve)
           APR_HOOK_LINK(test_config)
           APR_HOOK_LINK(open_htaccess)
)

AP_IMPLEMENT_HOOK_RUN_ALL(int, header_parser,
                          (request_rec *r), (r), OK, DECLINED)

AP_IMPLEMENT_HOOK_RUN_ALL(int, pre_config,
                          (apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp),
                          (pconf, plog, ptemp), OK, DECLINED)

AP_IMPLEMENT_HOOK_RUN_ALL(int, check_config,
                          (apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp, server_rec *s),
                          (pconf, plog, ptemp, s), OK, DECLINED)

AP_IMPLEMENT_HOOK_VOID(test_config,
                       (apr_pool_t *pconf, server_rec *s),
                       (pconf, s))

AP_IMPLEMENT_HOOK_RUN_ALL(int, post_config,
                          (apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp, server_rec *s),
                          (pconf, plog, ptemp, s), OK, DECLINED)

/* During the course of debugging I expanded this macro out, so
 * rather than remove all the useful information there is in the
 * following lines, I'm going to leave it here in case anyone
 * else finds it useful.
 *
 * Ben has looked at it and thinks it correct :)
 *
AP_DECLARE(int) ap_hook_post_config(ap_HOOK_post_config_t *pf,
                                    const char * const *aszPre,
                                    const char * const *aszSucc,
                                    int nOrder)
{
    ap_LINK_post_config_t *pHook;

    if (!_hooks.link_post_config) {
        _hooks.link_post_config = apr_array_make(apr_hook_global_pool, 1,
                                                 sizeof(ap_LINK_post_config_t));
        apr_hook_sort_register("post_config", &_hooks.link_post_config);
    }

    pHook = apr_array_push(_hooks.link_post_config);
    pHook->pFunc = pf;
    pHook->aszPredecessors = aszPre;
    pHook->aszSuccessors = aszSucc;
    pHook->nOrder = nOrder;
    pHook->szName = apr_hook_debug_current;

    if (apr_hook_debug_enabled)
        apr_hook_debug_show("post_config", aszPre, aszSucc);
}

AP_DECLARE(apr_array_header_t *) ap_hook_get_post_config(void)
{
    return _hooks.link_post_config;
}

AP_DECLARE(int) ap_run_post_config(apr_pool_t *pconf,
                                   apr_pool_t *plog,
                                   apr_pool_t *ptemp,
                                   server_rec *s)
{
    ap_LINK_post_config_t *pHook;
    int n;

    if (!_hooks.link_post_config)
        return;

    pHook = (ap_LINK_post_config_t *)_hooks.link_post_config->elts;
    for (n = 0; n < _hooks.link_post_config->nelts; ++n)
        pHook[n].pFunc (pconf, plog, ptemp, s);
}
 */

AP_IMPLEMENT_HOOK_RUN_ALL(int, open_logs,
                          (apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp, server_rec *s),
                          (pconf, plog, ptemp, s), OK, DECLINED)

AP_IMPLEMENT_HOOK_VOID(child_init,
                       (apr_pool_t *pchild, server_rec *s),
                       (pchild, s))

AP_IMPLEMENT_HOOK_RUN_FIRST(int, handler, (request_rec *r),
                            (r), DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(int, quick_handler, (request_rec *r, int lookup),
                            (r, lookup), DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t, open_htaccess,
                            (request_rec *r, const char *dir_name, const char *access_name,
                             ap_configfile_t **conffile, const char **full_name),
                            (r, dir_name, access_name, conffile, full_name),
                            AP_DECLINED)

/* hooks with no args are implemented last, after disabling APR hook probes */
#if defined(APR_HOOK_PROBES_ENABLED)
#undef APR_HOOK_PROBES_ENABLED
#undef APR_HOOK_PROBE_ENTRY
#define APR_HOOK_PROBE_ENTRY(ud,ns,name,args)
#undef APR_HOOK_PROBE_RETURN
#define APR_HOOK_PROBE_RETURN(ud,ns,name,rv,args)
#undef APR_HOOK_PROBE_INVOKE
#define APR_HOOK_PROBE_INVOKE(ud,ns,name,src,args)
#undef APR_HOOK_PROBE_COMPLETE
#define APR_HOOK_PROBE_COMPLETE(ud,ns,name,src,rv,args)
#undef APR_HOOK_INT_DCL_UD
#define APR_HOOK_INT_DCL_UD
#endif
AP_IMPLEMENT_HOOK_VOID(optional_fn_retrieve, (void), ())

/****************************************************************
 *
 * We begin with the functions which deal with the linked list
 * of modules which control just about all of the server operation.
 */

/* total_modules is the number of modules that have been linked
 * into the server.
 */
static int total_modules = 0;

/* dynamic_modules is the number of modules that have been added
 * after the pre-loaded ones have been set up. It shouldn't be larger
 * than DYNAMIC_MODULE_LIMIT.
 */
static int dynamic_modules = 0;

/* The maximum possible value for total_modules, i.e. number of static
 * modules plus DYNAMIC_MODULE_LIMIT.
 */
static int max_modules = 0;

/* The number of elements we need to alloc for config vectors. Before loading
 * of dynamic modules, we must be liberal and set this to max_modules. After
 * loading of dynamic modules, we can trim it down to total_modules. On
 * restart, reset to max_modules.
 */
static int conf_vector_length = 0;

static int reserved_module_slots = 0;

AP_DECLARE_DATA module *ap_top_module = NULL;
AP_DECLARE_DATA module **ap_loaded_modules=NULL;

static apr_hash_t *ap_config_hash = NULL;

/* a list of the module symbol names with the trailing "_module"removed */
static char **ap_module_short_names = NULL;

typedef int (*handler_func)(request_rec *);
typedef void *(*dir_maker_func)(apr_pool_t *, char *);
typedef void *(*merger_func)(apr_pool_t *, void *, void *);

/* A list of the merge_dir_config functions of all loaded modules, sorted
 * by module_index.
 * Using this list in ap_merge_per_dir_configs() is faster than following
 * the module->next linked list because of better memory locality (resulting
 * in better cache usage).
 */
static merger_func *merger_func_cache;

/* maximum nesting level for config directories */
#ifndef AP_MAX_INCLUDE_DIR_DEPTH
#define AP_MAX_INCLUDE_DIR_DEPTH (128)
#endif

/* Dealing with config vectors.  These are associated with per-directory,
 * per-server, and per-request configuration, and have a void* pointer for
 * each modules.  The nature of the structure pointed to is private to the
 * module in question... the core doesn't (and can't) know.  However, there
 * are defined interfaces which allow it to create instances of its private
 * per-directory and per-server structures, and to merge the per-directory
 * structures of a directory and its subdirectory (producing a new one in
 * which the defaults applying to the base directory have been properly
 * overridden).
 */

static ap_conf_vector_t *create_empty_config(apr_pool_t *p)
{
    void *conf_vector = apr_pcalloc(p, sizeof(void *) * conf_vector_length);
    return conf_vector;
}

static ap_conf_vector_t *create_default_per_dir_config(apr_pool_t *p)
{
    void **conf_vector = apr_pcalloc(p, sizeof(void *) * conf_vector_length);
    module *modp;

    for (modp = ap_top_module; modp; modp = modp->next) {
        dir_maker_func df = modp->create_dir_config;

        if (df)
            conf_vector[modp->module_index] = (*df)(p, NULL);
    }

    return (ap_conf_vector_t *)conf_vector;
}

AP_CORE_DECLARE(ap_conf_vector_t *) ap_merge_per_dir_configs(apr_pool_t *p,
                                           ap_conf_vector_t *base,
                                           ap_conf_vector_t *new_conf)
{
    void **conf_vector = apr_palloc(p, sizeof(void *) * conf_vector_length);
    void **base_vector = (void **)base;
    void **new_vector = (void **)new_conf;
    int i;

    for (i = 0; i < total_modules; i++) {
        if (!new_vector[i]) {
            conf_vector[i] = base_vector[i];
        }
        else {
            const merger_func df = merger_func_cache[i];
            if (df && base_vector[i]) {
                conf_vector[i] = (*df)(p, base_vector[i], new_vector[i]);
            }
            else
                conf_vector[i] = new_vector[i];
        }
    }

    return (ap_conf_vector_t *)conf_vector;
}

static ap_conf_vector_t *create_server_config(apr_pool_t *p, server_rec *s)
{
    void **conf_vector = apr_pcalloc(p, sizeof(void *) * conf_vector_length);
    module *modp;

    for (modp = ap_top_module; modp; modp = modp->next) {
        if (modp->create_server_config)
            conf_vector[modp->module_index] = (*modp->create_server_config)(p, s);
    }

    return (ap_conf_vector_t *)conf_vector;
}

static void merge_server_configs(apr_pool_t *p, ap_conf_vector_t *base,
                                 ap_conf_vector_t *virt)
{
    /* Can reuse the 'virt' vector for the spine of it, since we don't
     * have to deal with the moral equivalent of .htaccess files here...
     */

    void **base_vector = (void **)base;
    void **virt_vector = (void **)virt;
    module *modp;

    for (modp = ap_top_module; modp; modp = modp->next) {
        merger_func df = modp->merge_server_config;
        int i = modp->module_index;

        if (!virt_vector[i])
            virt_vector[i] = base_vector[i];
        else if (df)
            virt_vector[i] = (*df)(p, base_vector[i], virt_vector[i]);
    }
}

AP_CORE_DECLARE(ap_conf_vector_t *) ap_create_request_config(apr_pool_t *p)
{
    return create_empty_config(p);
}

AP_CORE_DECLARE(ap_conf_vector_t *) ap_create_conn_config(apr_pool_t *p)
{
    return create_empty_config(p);
}

AP_CORE_DECLARE(ap_conf_vector_t *) ap_create_per_dir_config(apr_pool_t *p)
{
    return create_empty_config(p);
}

/* Invoke the filter_init_func for all filters with FILTERS where f->r
 * matches R.  Restricting to a matching R avoids re-running init
 * functions for filters configured for r->main where r is a
 * subrequest.  */
static int invoke_filter_init(request_rec *r, ap_filter_t *filters)
{
    while (filters) {
        if (filters->frec->filter_init_func && filters->r == r) {
            int result = filters->frec->filter_init_func(filters);
            if (result != OK) {
                return result;
            }
        }
        filters = filters->next;
    }
    return OK;
}

AP_CORE_DECLARE(int) ap_invoke_handler(request_rec *r)
{
    const char *handler;
    const char *p;
    int result;
    const char *old_handler = r->handler;
    const char *ignore;

    /*
     * The new insert_filter stage makes the most sense here.  We only use
     * it when we are going to run the request, so we must insert filters
     * if any are available.  Since the goal of this phase is to allow all
     * modules to insert a filter if they want to, this filter returns
     * void.  I just can't see any way that this filter can reasonably
     * fail, either your modules inserts something or it doesn't.  rbb
     */
    ap_run_insert_filter(r);

    /* Before continuing, allow each filter that is in the two chains to
     * run their init function to let them do any magic before we could
     * start generating data.
     */
    result = invoke_filter_init(r, r->input_filters);
    if (result != OK) {
        return result;
    }
    result = invoke_filter_init(r, r->output_filters);
    if (result != OK) {
        return result;
    }

    if (!r->handler) {
        if (r->content_type) {
            handler = r->content_type;
            if ((p=ap_strchr_c(handler, ';')) != NULL) {
                char *new_handler = (char *)apr_pmemdup(r->pool, handler,
                                                        p - handler + 1);
                char *p2 = new_handler + (p - handler);
                handler = new_handler;

                /* exclude media type arguments */
                while (p2 > handler && p2[-1] == ' ')
                    --p2; /* strip trailing spaces */

                *p2='\0';
            }
        }
        else {
            handler = AP_DEFAULT_HANDLER_NAME;
        }

        r->handler = handler;
    }

    result = ap_run_handler(r);

    r->handler = old_handler;

    if (result == DECLINED && r->handler && r->filename) {
        ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(00523)
            "handler \"%s\" not found for: %s", r->handler, r->filename);
    }
    if ((result != OK) && (result != DONE) && (result != DECLINED) && (result != SUSPENDED)
        && (result != AP_FILTER_ERROR) /* ap_die() knows about this specifically */
        && !ap_is_HTTP_VALID_RESPONSE(result)) {
        /* If a module is deliberately returning something else
         * (request_rec in non-HTTP or proprietary extension?)
         * let it set a note to allow it explicitly.
         * Otherwise, a return code that is neither reserved nor HTTP
         * is a bug, as in PR#31759.
         */
        ignore = apr_table_get(r->notes, "HTTP_IGNORE_RANGE");
        if (!ignore) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00524)
                          "Handler for %s returned invalid result code %d",
                          r->handler, result);
            result = HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    return result == DECLINED ? HTTP_INTERNAL_SERVER_ERROR : result;
}

AP_DECLARE(int) ap_method_is_limited(cmd_parms *cmd, const char *method)
{
    int methnum;

    methnum = ap_method_number_of(method);

    /*
     * A method number either hardcoded into apache or
     * added by a module and registered.
     */
    if (methnum != M_INVALID) {
        return (cmd->limited & (AP_METHOD_BIT << methnum)) ? 1 : 0;
    }

    return 0; /* not found */
}

AP_DECLARE(void) ap_register_hooks(module *m, apr_pool_t *p)
{
    if (m->register_hooks) {
        if (getenv("SHOW_HOOKS")) {
            printf("Registering hooks for %s\n", m->name);
            apr_hook_debug_enabled = 1;
        }

        apr_hook_debug_current = m->name;
        m->register_hooks(p);
    }
}

static void ap_add_module_commands(module *m, apr_pool_t *p);

typedef struct ap_mod_list_struct ap_mod_list;
struct ap_mod_list_struct {
    struct ap_mod_list_struct *next;
    module *m;
    const command_rec *cmd;
};

static void rebuild_conf_hash(apr_pool_t *p, int add_prelinked)
{
    module **m;

    ap_config_hash = apr_hash_make(p);

    apr_pool_cleanup_register(p, &ap_config_hash, ap_pool_cleanup_set_null,
                              apr_pool_cleanup_null);
    if (add_prelinked) {
        for (m = ap_prelinked_modules; *m != NULL; m++) {
            ap_add_module_commands(*m, p);
        }
    }
}

static void ap_add_module_commands(module *m, apr_pool_t *p)
{
    apr_pool_t *tpool;
    ap_mod_list *mln;
    const command_rec *cmd;
    char *dir;

    cmd = m->cmds;

    if (ap_config_hash == NULL) {
        rebuild_conf_hash(p, 0);
    }

    tpool = apr_hash_pool_get(ap_config_hash);

    while (cmd && cmd->name) {
        mln = apr_palloc(tpool, sizeof(ap_mod_list));
        mln->cmd = cmd;
        mln->m = m;
        dir = apr_pstrdup(tpool, cmd->name);

        ap_str_tolower(dir);

        mln->next = apr_hash_get(ap_config_hash, dir, APR_HASH_KEY_STRING);
        apr_hash_set(ap_config_hash, dir, APR_HASH_KEY_STRING, mln);
        ++cmd;
    }
}


/* One-time setup for precompiled modules --- NOT to be done on restart */

AP_DECLARE(const char *) ap_add_module(module *m, apr_pool_t *p,
                                       const char *sym_name)
{
    ap_module_symbol_t *sym = ap_prelinked_module_symbols;

    /* This could be called from a LoadModule httpd.conf command,
     * after the file has been linked and the module structure within it
     * teased out...
     */

    if (m->version != MODULE_MAGIC_NUMBER_MAJOR) {
        return apr_psprintf(p, "Module \"%s\" is not compatible with this "
                            "version of Apache (found %d, need %d). Please "
                            "contact the vendor for the correct version.",
                            m->name, m->version, MODULE_MAGIC_NUMBER_MAJOR);
    }

    if (m->module_index == -1) {
        if (dynamic_modules >= DYNAMIC_MODULE_LIMIT) {
            return apr_psprintf(p, "Module \"%s\" could not be loaded, "
                                "because the dynamic module limit was "
                                "reached. Please increase "
                                "DYNAMIC_MODULE_LIMIT and recompile.", m->name);
        }
        /*
         * If this fails some module forgot to call ap_reserve_module_slots*.
         */
        ap_assert(total_modules < conf_vector_length);

        m->module_index = total_modules++;
        dynamic_modules++;

    }
    else if (!sym_name) {
        while (sym->modp != NULL) {
            if (sym->modp == m) {
                sym_name = sym->name;
                break;
            }
            sym++;
        }
    }

    if (m->next == NULL) {
        m->next = ap_top_module;
        ap_top_module = m;
    }

    if (sym_name) {
        int len = strlen(sym_name);
        int slen = strlen("_module");
        if (len > slen && !strcmp(sym_name + len - slen, "_module")) {
            len -= slen;
        }

        ap_module_short_names[m->module_index] = ap_malloc(len + 1);
        memcpy(ap_module_short_names[m->module_index], sym_name, len);
        ap_module_short_names[m->module_index][len] = '\0';
        merger_func_cache[m->module_index] = m->merge_dir_config;
    }


    /* Some C compilers put a complete path into __FILE__, but we want
     * only the filename (e.g. mod_includes.c). So check for path
     * components (Unix and DOS), and remove them.
     */

    if (ap_strrchr_c(m->name, '/'))
        m->name = 1 + ap_strrchr_c(m->name, '/');

    if (ap_strrchr_c(m->name, '\\'))
        m->name = 1 + ap_strrchr_c(m->name, '\\');

#ifdef _OSD_POSIX
    /* __FILE__ =
     * "*POSIX(/home/martin/apache/src/modules/standard/mod_info.c)"
     */

    /* We cannot fix the string in-place, because it's const */
    if (m->name[strlen(m->name)-1] == ')') {
        char *tmp = ap_malloc(strlen(m->name)); /* FIXME: memory leak, albeit a small one */
        memcpy(tmp, m->name, strlen(m->name)-1);
        tmp[strlen(m->name)-1] = '\0';
        m->name = tmp;
    }
#endif /*_OSD_POSIX*/

    ap_add_module_commands(m, p);
    /*  FIXME: is this the right place to call this?
     *  It doesn't appear to be
     */
    ap_register_hooks(m, p);

    return NULL;
}

/*
 * remove_module undoes what add_module did. There are some caveats:
 * when the module is removed, its slot is lost so all the current
 * per-dir and per-server configurations are invalid. So we should
 * only ever call this function when you are invalidating almost
 * all our current data. I.e. when doing a restart.
 */

AP_DECLARE(void) ap_remove_module(module *m)
{
    module *modp;

    modp = ap_top_module;
    if (modp == m) {
        /* We are the top module, special case */
        ap_top_module = modp->next;
        m->next = NULL;
    }
    else {
        /* Not the top module, find use. When found modp will
         * point to the module _before_ us in the list
         */

        while (modp && modp->next != m) {
            modp = modp->next;
        }

        if (!modp) {
            /* Uh-oh, this module doesn't exist */
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, APLOGNO(00525)
                         "Cannot remove module %s: not found in module list",
                         m->name);
            return;
        }

        /* Eliminate us from the module list */
        modp->next = modp->next->next;
    }

    free(ap_module_short_names[m->module_index]);
    ap_module_short_names[m->module_index] = NULL;
    merger_func_cache[m->module_index] = NULL;

    m->module_index = -1; /* simulate being unloaded, should
                           * be unnecessary */
    dynamic_modules--;
    total_modules--;
}

AP_DECLARE(const char *) ap_add_loaded_module(module *mod, apr_pool_t *p,
                                              const char *short_name)
{
    module **m;
    const char *error;

    /*
     *  Add module pointer to top of chained module list
     */
    error = ap_add_module(mod, p, short_name);
    if (error) {
        return error;
    }

    /*
     *  And module pointer to list of loaded modules
     *
     *  Notes: 1. ap_add_module() would already complain if no more space
     *            exists for adding a dynamically loaded module
     *         2. ap_add_module() accepts double inclusion, so we have
     *            to accept this, too.
     */
    for (m = ap_loaded_modules; *m != NULL; m++)
        ;
    *m++ = mod;
    *m = NULL;

    return NULL;
}

AP_DECLARE(void) ap_remove_loaded_module(module *mod)
{
    module **m;
    module **m2;
    int done;

    /*
     *  Remove module pointer from chained module list
     */
    ap_remove_module(mod);

    /*
     *  Remove module pointer from list of loaded modules
     *
     *  Note: 1. We cannot determine if the module was successfully
     *           removed by ap_remove_module().
     *        2. We have not to complain explicitly when the module
     *           is not found because ap_remove_module() did it
     *           for us already.
     */
    for (m = m2 = ap_loaded_modules, done = 0; *m2 != NULL; m2++) {
        if (*m2 == mod && done == 0)
            done = 1;
        else
            *m++ = *m2;
    }

    *m = NULL;
}

AP_DECLARE(const char *) ap_setup_prelinked_modules(process_rec *process)
{
    module **m;
    module **m2;
    const char *error;

    apr_hook_global_pool=process->pconf;

    rebuild_conf_hash(process->pconf, 0);

    /*
     *  Initialise total_modules variable and module indices
     */
    total_modules = 0;
    for (m = ap_preloaded_modules; *m != NULL; m++)
        (*m)->module_index = total_modules++;

    max_modules = total_modules + DYNAMIC_MODULE_LIMIT + 1;
    conf_vector_length = max_modules;

    /*
     *  Initialise list of loaded modules and short names
     */
    ap_loaded_modules = (module **)apr_palloc(process->pool,
        sizeof(module *) * conf_vector_length);
    if (!ap_module_short_names)
        ap_module_short_names = ap_calloc(sizeof(char *), conf_vector_length);

    if (!merger_func_cache)
        merger_func_cache = ap_calloc(sizeof(merger_func), conf_vector_length);

    if (ap_loaded_modules == NULL || ap_module_short_names == NULL
        || merger_func_cache == NULL)
        return "Ouch! Out of memory in ap_setup_prelinked_modules()!";

    for (m = ap_preloaded_modules, m2 = ap_loaded_modules; *m != NULL; )
        *m2++ = *m++;

    *m2 = NULL;

    /*
     *   Initialize chain of linked (=activate) modules
     */
    for (m = ap_prelinked_modules; *m != NULL; m++) {
        error = ap_add_module(*m, process->pconf, NULL);
        if (error) {
            return error;
        }
    }

    apr_hook_sort_all();

    return NULL;
}

AP_DECLARE(const char *) ap_find_module_name(module *m)
{
    return m->name;
}

AP_DECLARE(const char *) ap_find_module_short_name(int module_index)
{
        if (module_index < 0 || module_index >= conf_vector_length)
                return NULL;
        return ap_module_short_names[module_index];
}

AP_DECLARE(module *) ap_find_linked_module(const char *name)
{
    module *modp;

    for (modp = ap_top_module; modp; modp = modp->next) {
        if (strcmp(modp->name, name) == 0)
            return modp;
    }

    return NULL;
}

/*****************************************************************
 *
 * Resource, access, and .htaccess config files now parsed by a common
 * command loop.
 *
 * Let's begin with the basics; parsing the line and
 * invoking the function...
 */

#define AP_MAX_ARGC 64

static const char *invoke_cmd(const command_rec *cmd, cmd_parms *parms,
                              void *mconfig, const char *args)
{
    int override_list_ok = 0;
    char *w, *w2, *w3;
    const char *errmsg = NULL;

    /* Have we been provided a list of acceptable directives? */
    if (parms->override_list != NULL) { 
         if (apr_table_get(parms->override_list, cmd->name) != NULL) { 
              override_list_ok = 1;
         }
    }

    if ((parms->override & cmd->req_override) == 0 && !override_list_ok) {
        if (parms->override & NONFATAL_OVERRIDE) {
            ap_log_perror(APLOG_MARK, APLOG_WARNING, 0, parms->temp_pool,
                          APLOGNO(02295)
                          "%s in .htaccess forbidden by AllowOverride",
                          cmd->name);
            return NULL;
        }
        else {
            return apr_pstrcat(parms->pool, cmd->name,
                               " not allowed here", NULL);
        }
    }

    parms->info = cmd->cmd_data;
    parms->cmd = cmd;

    switch (cmd->args_how) {
    case RAW_ARGS:
#ifdef RESOLVE_ENV_PER_TOKEN
        args = ap_resolve_env(parms->pool,args);
#endif
        return cmd->AP_RAW_ARGS(parms, mconfig, args);

    case TAKE_ARGV:
        {
            char *argv[AP_MAX_ARGC];
            int argc = 0;

            do {
                w = ap_getword_conf(parms->pool, &args);
                if (*w == '\0' && *args == '\0') {
                    break;
                }
                argv[argc] = w;
                argc++;
            } while (argc < AP_MAX_ARGC && *args != '\0');

            return cmd->AP_TAKE_ARGV(parms, mconfig, argc, argv);
        }

    case NO_ARGS:
        if (*args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes no arguments",
                               NULL);

        return cmd->AP_NO_ARGS(parms, mconfig);

    case TAKE1:
        w = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes one argument",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE1(parms, mconfig, w);

    case TAKE2:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *w2 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes two arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE2(parms, mconfig, w, w2);

    case TAKE12:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes 1-2 arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE2(parms, mconfig, w, *w2 ? w2 : NULL);

    case TAKE3:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);
        w3 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *w2 == '\0' || *w3 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE23:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || *w2 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes two or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE123:
        w = ap_getword_conf(parms->pool, &args);
        w2 = *args ? ap_getword_conf(parms->pool, &args) : NULL;
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes one, two or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE13:
        w = ap_getword_conf(parms->pool, &args);
        w2 = *args ? ap_getword_conf(parms->pool, &args) : NULL;
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || (w2 && *w2 && !w3) || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes one or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case ITERATE:
        w = ap_getword_conf(parms->pool, &args);
        
        if (*w == '\0')
            return apr_pstrcat(parms->pool, cmd->name,
                               " requires at least one argument",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        while (*w != '\0') {
            errmsg = cmd->AP_TAKE1(parms, mconfig, w);

            if (errmsg && strcmp(errmsg, DECLINE_CMD) != 0)
                return errmsg;

            w = ap_getword_conf(parms->pool, &args);
        }

        return errmsg;