core.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 2001-2005 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.
 */

#include "apr.h"
#include "apr_strings.h"
#include "apr_lib.h"
#include "apr_fnmatch.h"
#include "apr_hash.h"
#include "apr_thread_proc.h"    /* for RLIMIT stuff */
#include "apr_hooks.h"

#define APR_WANT_IOVEC
#define APR_WANT_STRFUNC
#define APR_WANT_MEMFUNC
#include "apr_want.h"

#define CORE_PRIVATE
#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_protocol.h" /* For index_of_response().  Grump. */
#include "http_request.h"
#include "http_vhost.h"
#include "http_main.h"     /* For the default_handler below... */
#include "http_log.h"
#include "rfc1413.h"
#include "util_md5.h"
#include "http_connection.h"
#include "apr_buckets.h"
#include "util_filter.h"
#include "util_ebcdic.h"
#include "mpm.h"
#include "mpm_common.h"
#include "scoreboard.h"
#include "mod_core.h"
#include "mod_proxy.h"
#include "ap_listen.h"

/* LimitRequestBody handling */
#define AP_LIMIT_REQ_BODY_UNSET         ((apr_off_t) -1)
#define AP_DEFAULT_LIMIT_REQ_BODY       ((apr_off_t) 0)

/* LimitXMLRequestBody handling */
#define AP_LIMIT_UNSET                  ((long) -1)
#define AP_DEFAULT_LIMIT_XML_BODY       ((size_t)1000000)

#define AP_MIN_SENDFILE_BYTES           (256)

/* maximum include nesting level */
#ifndef AP_MAX_INCLUDE_DEPTH
#define AP_MAX_INCLUDE_DEPTH            (128)
#endif

APR_HOOK_STRUCT(
    APR_HOOK_LINK(get_mgmt_items)
)

AP_IMPLEMENT_HOOK_RUN_ALL(int, get_mgmt_items,
                          (apr_pool_t *p, const char *val, apr_hash_t *ht),
                          (p, val, ht), OK, DECLINED)

/* Server core module... This module provides support for really basic
 * server operations, including options and commands which control the
 * operation of other modules.  Consider this the bureaucracy module.
 *
 * The core module also defines handlers, etc., do handle just enough
 * to allow a server with the core module ONLY to actually serve documents
 * (though it slaps DefaultType on all of 'em); this was useful in testing,
 * but may not be worth preserving.
 *
 * This file could almost be mod_core.c, except for the stuff which affects
 * the http_conf_globals.
 */

/* Handles for core filters */
AP_DECLARE_DATA ap_filter_rec_t *ap_subreq_core_filter_handle;
AP_DECLARE_DATA ap_filter_rec_t *ap_core_output_filter_handle;
AP_DECLARE_DATA ap_filter_rec_t *ap_content_length_filter_handle;
AP_DECLARE_DATA ap_filter_rec_t *ap_net_time_filter_handle;
AP_DECLARE_DATA ap_filter_rec_t *ap_core_input_filter_handle;

/* magic pointer for ErrorDocument xxx "default" */
static char errordocument_default;

static void *create_core_dir_config(apr_pool_t *a, char *dir)
{
    core_dir_config *conf;
    int i;

    conf = (core_dir_config *)apr_pcalloc(a, sizeof(core_dir_config));

    /* conf->r and conf->d[_*] are initialized by dirsection() or left NULL */

    conf->opts = dir ? OPT_UNSET : OPT_UNSET|OPT_ALL;
    conf->opts_add = conf->opts_remove = OPT_NONE;
    conf->override = dir ? OR_UNSET : OR_UNSET|OR_ALL;

    conf->content_md5 = 2;
    conf->accept_path_info = 3;

    conf->use_canonical_name = USE_CANONICAL_NAME_UNSET;

    conf->hostname_lookups = HOSTNAME_LOOKUP_UNSET;
    conf->do_rfc1413 = DEFAULT_RFC1413 | 2; /* set bit 1 to indicate default */
    conf->satisfy = apr_palloc(a, sizeof(*conf->satisfy) * METHODS);
    for (i = 0; i < METHODS; ++i) {
        conf->satisfy[i] = SATISFY_NOSPEC;
    }

#ifdef RLIMIT_CPU
    conf->limit_cpu = NULL;
#endif
#if defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_AS)
    conf->limit_mem = NULL;
#endif
#ifdef RLIMIT_NPROC
    conf->limit_nproc = NULL;
#endif

    conf->limit_req_body = AP_LIMIT_REQ_BODY_UNSET;
    conf->limit_xml_body = AP_LIMIT_UNSET;
    conf->sec_file = apr_array_make(a, 2, sizeof(ap_conf_vector_t *));

    conf->server_signature = srv_sig_unset;

    conf->add_default_charset = ADD_DEFAULT_CHARSET_UNSET;
    conf->add_default_charset_name = DEFAULT_ADD_DEFAULT_CHARSET_NAME;

    /* Overriding all negotiation
     */
    conf->mime_type = NULL;
    conf->handler = NULL;
    conf->output_filters = NULL;
    conf->input_filters = NULL;

    /*
     * Flag for use of inodes in ETags.
     */
    conf->etag_bits = ETAG_UNSET;
    conf->etag_add = ETAG_UNSET;
    conf->etag_remove = ETAG_UNSET;

    conf->enable_mmap = ENABLE_MMAP_UNSET;
    conf->enable_sendfile = ENABLE_SENDFILE_UNSET;
    conf->allow_encoded_slashes = 0;

    return (void *)conf;
}

/*
 * Overlay one hash table of ct_output_filters onto another
 */
static void *merge_ct_filters(apr_pool_t *p,
                              const void *key,
                              apr_ssize_t klen,
                              const void *overlay_val,
                              const void *base_val,
                              const void *data)
{
    ap_filter_rec_t *cur;
    const ap_filter_rec_t *overlay_info = (const ap_filter_rec_t *)overlay_val;
    const ap_filter_rec_t *base_info = (const ap_filter_rec_t *)base_val;

    cur = NULL;

    while (overlay_info) {
        ap_filter_rec_t *new;

        new = apr_pcalloc(p, sizeof(ap_filter_rec_t));
        new->name = apr_pstrdup(p, overlay_info->name);
        new->next = cur;
        cur = new;
        overlay_info = overlay_info->next;
    }

    while (base_info) {
        ap_filter_rec_t *f;
        int found = 0;

        /* We can't have dups. */
        f = cur;
        while (f) {
            if (!strcasecmp(base_info->name, f->name)) {
                found = 1;
                break;
            }

            f = f->next;
        }

        if (!found) {
            f = apr_pcalloc(p, sizeof(ap_filter_rec_t));
            f->name = apr_pstrdup(p, base_info->name);
            f->next = cur;
            cur = f;
        }

        base_info = base_info->next;
    }

    return cur;
}

static void *merge_core_dir_configs(apr_pool_t *a, void *basev, void *newv)
{
    core_dir_config *base = (core_dir_config *)basev;
    core_dir_config *new = (core_dir_config *)newv;
    core_dir_config *conf;
    int i;

    /* Create this conf by duplicating the base, replacing elements
     * (or creating copies for merging) where new-> values exist.
     */
    conf = (core_dir_config *)apr_palloc(a, sizeof(core_dir_config));
    memcpy(conf, base, sizeof(core_dir_config));

    conf->d = new->d;
    conf->d_is_fnmatch = new->d_is_fnmatch;
    conf->d_components = new->d_components;
    conf->r = new->r;

    if (new->opts & OPT_UNSET) {
        /* there was no explicit setting of new->opts, so we merge
         * preserve the invariant (opts_add & opts_remove) == 0
         */
        conf->opts_add = (conf->opts_add & ~new->opts_remove) | new->opts_add;
        conf->opts_remove = (conf->opts_remove & ~new->opts_add)
                            | new->opts_remove;
        conf->opts = (conf->opts & ~conf->opts_remove) | conf->opts_add;
        if ((base->opts & OPT_INCNOEXEC) && (new->opts & OPT_INCLUDES)) {
            conf->opts = (conf->opts & ~OPT_INCNOEXEC) | OPT_INCLUDES;
        }
    }
    else {
        /* otherwise we just copy, because an explicit opts setting
         * overrides all earlier +/- modifiers
         */
        conf->opts = new->opts;
        conf->opts_add = new->opts_add;
        conf->opts_remove = new->opts_remove;
    }

    if (!(new->override & OR_UNSET)) {
        conf->override = new->override;
    }

    if (new->ap_default_type) {
        conf->ap_default_type = new->ap_default_type;
    }

    if (new->ap_auth_type) {
        conf->ap_auth_type = new->ap_auth_type;
    }

    if (new->ap_auth_name) {
        conf->ap_auth_name = new->ap_auth_name;
    }

    if (new->ap_requires) {
        conf->ap_requires = new->ap_requires;
    }

    if (conf->response_code_strings == NULL) {
        conf->response_code_strings = new->response_code_strings;
    }
    else if (new->response_code_strings != NULL) {
        /* If we merge, the merge-result must have it's own array
         */
        conf->response_code_strings = apr_palloc(a,
            sizeof(*conf->response_code_strings) * RESPONSE_CODES);
        memcpy(conf->response_code_strings, base->response_code_strings,
               sizeof(*conf->response_code_strings) * RESPONSE_CODES);

        for (i = 0; i < RESPONSE_CODES; ++i) {
            if (new->response_code_strings[i] != NULL) {
                conf->response_code_strings[i] = new->response_code_strings[i];
            }
        }
    }
    /* Otherwise we simply use the base->response_code_strings array
     */

    if (new->hostname_lookups != HOSTNAME_LOOKUP_UNSET) {
        conf->hostname_lookups = new->hostname_lookups;
    }

    if ((new->do_rfc1413 & 2) == 0) {
        conf->do_rfc1413 = new->do_rfc1413;
    }

    if ((new->content_md5 & 2) == 0) {
        conf->content_md5 = new->content_md5;
    }

    if (new->accept_path_info != 3) {
        conf->accept_path_info = new->accept_path_info;
    }

    if (new->use_canonical_name != USE_CANONICAL_NAME_UNSET) {
        conf->use_canonical_name = new->use_canonical_name;
    }

#ifdef RLIMIT_CPU
    if (new->limit_cpu) {
        conf->limit_cpu = new->limit_cpu;
    }
#endif

#if defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_AS)
    if (new->limit_mem) {
        conf->limit_mem = new->limit_mem;
    }
#endif

#ifdef RLIMIT_NPROC
    if (new->limit_nproc) {
        conf->limit_nproc = new->limit_nproc;
    }
#endif

    if (new->limit_req_body != AP_LIMIT_REQ_BODY_UNSET) {
        conf->limit_req_body = new->limit_req_body;
    }

    if (new->limit_xml_body != AP_LIMIT_UNSET)
        conf->limit_xml_body = new->limit_xml_body;
    else
        conf->limit_xml_body = base->limit_xml_body;

    if (!conf->sec_file) {
        conf->sec_file = new->sec_file;
    }
    else if (new->sec_file) {
        /* If we merge, the merge-result must have it's own array
         */
        conf->sec_file = apr_array_append(a, base->sec_file, new->sec_file);
    }
    /* Otherwise we simply use the base->sec_file array
     */

    /* use a separate ->satisfy[] array either way */
    conf->satisfy = apr_palloc(a, sizeof(*conf->satisfy) * METHODS);
    for (i = 0; i < METHODS; ++i) {
        if (new->satisfy[i] != SATISFY_NOSPEC) {
            conf->satisfy[i] = new->satisfy[i];
        } else {
            conf->satisfy[i] = base->satisfy[i];
        }
    }

    if (new->server_signature != srv_sig_unset) {
        conf->server_signature = new->server_signature;
    }

    if (new->add_default_charset != ADD_DEFAULT_CHARSET_UNSET) {
        conf->add_default_charset = new->add_default_charset;
        conf->add_default_charset_name = new->add_default_charset_name;
    }

    /* Overriding all negotiation
     */
    if (new->mime_type) {
        conf->mime_type = new->mime_type;
    }

    if (new->handler) {
        conf->handler = new->handler;
    }

    if (new->output_filters) {
        conf->output_filters = new->output_filters;
    }

    if (new->input_filters) {
        conf->input_filters = new->input_filters;
    }

    if (conf->ct_output_filters && new->ct_output_filters) {
        conf->ct_output_filters = apr_hash_merge(a,
                                                 new->ct_output_filters,
                                                 conf->ct_output_filters,
                                                 merge_ct_filters,
                                                 NULL);
    }
    else if (new->ct_output_filters) {
        conf->ct_output_filters = apr_hash_copy(a, new->ct_output_filters);
    }
    else if (conf->ct_output_filters) {
        /* That memcpy above isn't enough. */
        conf->ct_output_filters = apr_hash_copy(a, base->ct_output_filters);
    }

    /*
     * Now merge the setting of the FileETag directive.
     */
    if (new->etag_bits == ETAG_UNSET) {
        conf->etag_add =
            (conf->etag_add & (~ new->etag_remove)) | new->etag_add;
        conf->etag_remove =
            (conf->opts_remove & (~ new->etag_add)) | new->etag_remove;
        conf->etag_bits =
            (conf->etag_bits & (~ conf->etag_remove)) | conf->etag_add;
    }
    else {
        conf->etag_bits = new->etag_bits;
        conf->etag_add = new->etag_add;
        conf->etag_remove = new->etag_remove;
    }

    if (conf->etag_bits != ETAG_NONE) {
        conf->etag_bits &= (~ ETAG_NONE);
    }

    if (new->enable_mmap != ENABLE_MMAP_UNSET) {
        conf->enable_mmap = new->enable_mmap;
    }

    if (new->enable_sendfile != ENABLE_SENDFILE_UNSET) {
        conf->enable_sendfile = new->enable_sendfile;
    }

    conf->allow_encoded_slashes = new->allow_encoded_slashes;
    
    return (void*)conf;
}

static void *create_core_server_config(apr_pool_t *a, server_rec *s)
{
    core_server_config *conf;
    int is_virtual = s->is_virtual;