config.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed 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 auxillary 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"

#define CORE_PRIVATE

#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 "mpm.h"


AP_DECLARE_DATA const char *ap_server_argv0 = NULL;

AP_DECLARE_DATA const char *ap_server_root = 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(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)
)

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, 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_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;

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

/* 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 *) *
                                    (total_modules + DYNAMIC_MODULE_LIMIT));
    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 *) *
                                     (total_modules + DYNAMIC_MODULE_LIMIT));
    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 *) * total_modules);
    void **base_vector = (void **)base;
    void **new_vector = (void **)new_conf;
    module *modp;

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

        if (!new_vector[i]) {
            conf_vector[i] = base_vector[i];
        }
        else {
            merger_func df = modp->merge_dir_config;
            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 *) *
                                     (total_modules + DYNAMIC_MODULE_LIMIT));
    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);
}

static int ap_invoke_filter_init(ap_filter_t *filters)
{
    while (filters) {
        if (filters->frec->filter_init_func) {
            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;

    /*
     * 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 = ap_invoke_filter_init(r->input_filters);
    if (result != OK) {
        return result;
    }
    result = ap_invoke_filter_init(r->output_filters);
    if (result != OK) {
        return result;
    }

    if (!r->handler) {
        handler = r->content_type ? r->content_type : ap_default_type(r);
        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;

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

            *p2='\0';
        }

        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,
            "handler \"%s\" not found for: %s", r->handler, r->filename);
    }

    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);
    }
}

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

AP_DECLARE(void) ap_add_module(module *m, apr_pool_t *p)
{