/* 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.

 */

/*

 * mod_vhost_alias.c: support for dynamically configured mass virtual hosting

 *

 * Copyright (c) 1998-1999 Demon Internet Ltd.

 *

 * This software was submitted by Demon Internet to the Apache Software Foundation

 * in May 1999. Future revisions and derivatives of this source code

 * must acknowledge Demon Internet as the original contributor of

 * this module. All other licensing and usage conditions are those

 * of the Apache Software Foundation.

 *

 * Originally written by Tony Finch <fanf@demon.net> <dot@dotat.at>.

 *

 * Implementation ideas were taken from mod_alias.c. The overall

 * concept is derived from the OVERRIDE_DOC_ROOT/OVERRIDE_CGIDIR

 * patch to Apache 1.3b3 and a similar feature in Demon's thttpd,

 * both written by James Grinter <jrg@blodwen.demon.co.uk>.

 */

#include "apr.h"

#include "apr_strings.h"

#include "ap_hooks.h"

#include "apr_lib.h"

#define APR_WANT_STRFUNC

#include "apr_want.h"

#include "httpd.h"

#include "http_config.h"

#include "http_core.h"

#include "http_request.h"  /* for ap_hook_translate_name */

module AP_MODULE_DECLARE_DATA vhost_alias_module;

/*

 * basic configuration things

 * we abbreviate "mod_vhost_alias" to "mva" for shorter names

 */

typedef enum {

    VHOST_ALIAS_UNSET, VHOST_ALIAS_NONE, VHOST_ALIAS_NAME, VHOST_ALIAS_IP

} mva_mode_e;

/*

 * Per-server module config record.

 */

typedef struct mva_sconf_t {

    const char *doc_root;

    const char *cgi_root;

    mva_mode_e doc_root_mode;

    mva_mode_e cgi_root_mode;

} mva_sconf_t;

static void *mva_create_server_config(apr_pool_t *p, server_rec *s)

{

    mva_sconf_t *conf;

    conf = (mva_sconf_t *) apr_pcalloc(p, sizeof(mva_sconf_t));

    conf->doc_root = NULL;

    conf->cgi_root = NULL;

    conf->doc_root_mode = VHOST_ALIAS_UNSET;

    conf->cgi_root_mode = VHOST_ALIAS_UNSET;

    return conf;

}

static void *mva_merge_server_config(apr_pool_t *p, void *parentv, void *childv)

{

    mva_sconf_t *parent = (mva_sconf_t *) parentv;

    mva_sconf_t *child = (mva_sconf_t *) childv;

    mva_sconf_t *conf;

    conf = (mva_sconf_t *) apr_pcalloc(p, sizeof(*conf));

    if (child->doc_root_mode == VHOST_ALIAS_UNSET) {

        conf->doc_root_mode = parent->doc_root_mode;

        conf->doc_root = parent->doc_root;

    }

    else {

        conf->doc_root_mode = child->doc_root_mode;

        conf->doc_root = child->doc_root;

    }

    if (child->cgi_root_mode == VHOST_ALIAS_UNSET) {

        conf->cgi_root_mode = parent->cgi_root_mode;

        conf->cgi_root = parent->cgi_root;

    }

    else {

        conf->cgi_root_mode = child->cgi_root_mode;

        conf->cgi_root = child->cgi_root;

    }

    return conf;

}

/*

 * These are just here to tell us what vhost_alias_set should do.

 * We don't put anything into them; we just use the cell addresses.

 */

static int vhost_alias_set_doc_root_ip,

    vhost_alias_set_cgi_root_ip,

    vhost_alias_set_doc_root_name,

    vhost_alias_set_cgi_root_name;

static const char *vhost_alias_set(cmd_parms *cmd, void *dummy, const char *map)

{

    mva_sconf_t *conf;

    mva_mode_e mode, *pmode;

    const char **pmap;

    const char *p;

    conf = (mva_sconf_t *) ap_get_module_config(cmd->server->module_config,

                                                &vhost_alias_module);

    /* there ought to be a better way of doing this */

    if (&vhost_alias_set_doc_root_ip == cmd->info) {

        mode = VHOST_ALIAS_IP;

        pmap = &conf->doc_root;

        pmode = &conf->doc_root_mode;

    }

    else if (&vhost_alias_set_cgi_root_ip == cmd->info) {

        mode = VHOST_ALIAS_IP;

        pmap = &conf->cgi_root;

        pmode = &conf->cgi_root_mode;

    }

    else if (&vhost_alias_set_doc_root_name == cmd->info) {

        mode = VHOST_ALIAS_NAME;

        pmap = &conf->doc_root;

        pmode = &conf->doc_root_mode;

    }

    else if (&vhost_alias_set_cgi_root_name == cmd->info) {

        mode = VHOST_ALIAS_NAME;

        pmap = &conf->cgi_root;

        pmode = &conf->cgi_root_mode;

    }

    else {

        return "INTERNAL ERROR: unknown command info";

    }

    if (!ap_os_is_path_absolute(cmd->pool, map)) {

        if (strcasecmp(map, "none")) {

            return "format string must be an absolute path, or 'none'";

        }

        *pmap = NULL;

        *pmode = VHOST_ALIAS_NONE;

        return NULL;

    }

    /* sanity check */

    p = map;

    while (*p != '\0') {

        if (*p++ != '%') {

            continue;

        }

        /* we just found a '%' */

        if (*p == 'p' || *p == '%') {

            ++p;

            continue;

        }

        /* optional dash */

        if (*p == '-') {

            ++p;

        }

        /* digit N */

        if (apr_isdigit(*p)) {

            ++p;

        }

        else {

            return "syntax error in format string";

        }

        /* optional plus */

        if (*p == '+') {

            ++p;

        }

        /* do we end here? */

        if (*p != '.') {

            continue;

        }

        ++p;

        /* optional dash */

        if (*p == '-') {

            ++p;

        }

        /* digit M */

        if (apr_isdigit(*p)) {

            ++p;

        }

        else {

            return "syntax error in format string";

        }

        /* optional plus */

        if (*p == '+') {

            ++p;

        }

    }

    *pmap = map;

    *pmode = mode;

    return NULL;

}

static const command_rec mva_commands[] =

{

    AP_INIT_TAKE1("VirtualScriptAlias", vhost_alias_set,

                  &vhost_alias_set_cgi_root_name, RSRC_CONF,

                  "how to create a ScriptAlias based on the host"),

    AP_INIT_TAKE1("VirtualDocumentRoot", vhost_alias_set,

                  &vhost_alias_set_doc_root_name, RSRC_CONF,

                  "how to create the DocumentRoot based on the host"),

    AP_INIT_TAKE1("VirtualScriptAliasIP", vhost_alias_set,

                  &vhost_alias_set_cgi_root_ip, RSRC_CONF,

                  "how to create a ScriptAlias based on the host"),

    AP_INIT_TAKE1("VirtualDocumentRootIP", vhost_alias_set,

                  &vhost_alias_set_doc_root_ip, RSRC_CONF,

                  "how to create the DocumentRoot based on the host"),

    { NULL }

};

/*

 * This really wants to be a nested function

 * but C is too feeble to support them.

 */

static APR_INLINE void vhost_alias_checkspace(request_rec *r, char *buf,

                                             char **pdest, int size)

{

    /* XXX: what if size > HUGE_STRING_LEN? */

    if (*pdest + size > buf + HUGE_STRING_LEN) {

        **pdest = '\0';

        if (r->filename) {

            r->filename = apr_pstrcat(r->pool, r->filename, buf, NULL);

        }

        else {

            r->filename = apr_pstrdup(r->pool, buf);

        }

        *pdest = buf;

    }

}

static void vhost_alias_interpolate(request_rec *r, const char *name,

                                    const char *map, const char *uri)

{

    /* 0..9 9..0 */

    enum { MAXDOTS = 19 };

    const char *dots[MAXDOTS+1];

    int ndots;

    char buf[HUGE_STRING_LEN];

    char *dest;

    const char *docroot;

    int N, M, Np, Mp, Nd, Md;

    const char *start, *end;

    const char *p;

    ndots = 0;

    dots[ndots++] = name-1; /* slightly naughty */

    for (p = name; *p; ++p) {

        if (*p == '.' && ndots < MAXDOTS) {

            dots[ndots++] = p;

        }

    }

    dots[ndots] = p;

    r->filename = NULL;

    dest = buf;

    while (*map) {

        if (*map != '%') {

            /* normal characters */

            vhost_alias_checkspace(r, buf, &dest, 1);

            *dest++ = *map++;

            continue;

        }

        /* we are in a format specifier */

        ++map;

        /* %% -> % */

        if (*map == '%') {

            ++map;

            vhost_alias_checkspace(r, buf, &dest, 1);

            *dest++ = '%';

            continue;

        }

        /* port number */

        if (*map == 'p') {

            ++map;

            /* no. of decimal digits in a short plus one */

            vhost_alias_checkspace(r, buf, &dest, 7);

            dest += apr_snprintf(dest, 7, "%d", ap_get_server_port(r));

            continue;

        }

        /* deal with %-N+.-M+ -- syntax is already checked */

        M = 0;   /* value */

        Np = Mp = 0; /* is there a plus? */

        Nd = Md = 0; /* is there a dash? */

        if (*map == '-') ++map, Nd = 1;

        N = *map++ - '0';

        if (*map == '+') ++map, Np = 1;

        if (*map == '.') {

            ++map;

            if (*map == '-') {

                ++map, Md = 1;

            }

            M = *map++ - '0';

            if (*map == '+') {

                ++map, Mp = 1;

            }

        }

        /* note that N and M are one-based indices, not zero-based */

        start = dots[0]+1; /* ptr to the first character */

        end = dots[ndots]; /* ptr to the character after the last one */

        if (N != 0) {

            if (N > ndots) {

                start = "_";

                end = start+1;

            }

            else if (!Nd) {

                start = dots[N-1]+1;

                if (!Np) {

                    end = dots[N];

                }

            }

            else {

                if (!Np) {

                    start = dots[ndots-N]+1;

                }

                end = dots[ndots-N+1];

            }

        }

        if (M != 0) {

            if (M > end - start) {

                start = "_";

                end = start+1;

            }

            else if (!Md) {

                start = start+M-1;

                if (!Mp) {

                    end = start+1;

                }

            }

            else {

                if (!Mp) {

                    start = end-M;

                }

                end = end-M+1;

            }

        }

        vhost_alias_checkspace(r, buf, &dest, end - start);

        for (p = start; p < end; ++p) {

            *dest++ = apr_tolower(*p);

        }

    }

    /* no double slashes */

    if (dest - buf > 0 && dest[-1] == '/') {

        --dest;

    }

    *dest = '\0';

    if (r->filename)

        docroot = apr_pstrcat(r->pool, r->filename, buf, NULL);

    else

        docroot = apr_pstrdup(r->pool, buf);

    r->filename = apr_pstrcat(r->pool, docroot, uri, NULL);

    ap_set_context_info(r, NULL, docroot);

    ap_set_document_root(r, docroot);

}

static int mva_translate(request_rec *r)

{

    mva_sconf_t *conf;

    const char *name, *map, *uri;

    mva_mode_e mode;

    const char *cgi;

    conf = (mva_sconf_t *) ap_get_module_config(r->server->module_config,

                                              &vhost_alias_module);

    cgi = NULL;

    if (conf->cgi_root) {

        cgi = strstr(r->uri, "cgi-bin/");

        if (cgi && (cgi != r->uri + strspn(r->uri, "/"))) {

            cgi = NULL;

        }

    }

    if (cgi) {

        mode = conf->cgi_root_mode;

        map = conf->cgi_root;

        uri = cgi + strlen("cgi-bin");

    }

    else if (r->uri[0] == '/') {

        mode = conf->doc_root_mode;

        map = conf->doc_root;

        uri = r->uri;

    }

    else {

        return DECLINED;

    }

    if (mode == VHOST_ALIAS_NAME) {

        name = ap_get_server_name(r);

    }

    else if (mode == VHOST_ALIAS_IP) {

        name = r->connection->local_ip;

    }

    else {

        return DECLINED;

    }

    /* ### There is an optimization available here to determine the

     * absolute portion of the path from the server config phase,

     * through the first % segment, and note that portion of the path

     * canonical_path buffer.

     */

    r->canonical_filename = "";

    vhost_alias_interpolate(r, name, map, uri);

    if (cgi) {

        /* see is_scriptaliased() in mod_cgi */

        r->handler = "cgi-script";

        apr_table_setn(r->notes, "alias-forced-type", r->handler);

        ap_set_context_info(r, "/cgi-bin", NULL);

    }

    return OK;

}

static void register_hooks(apr_pool_t *p)

{

    static const char * const aszPre[]={ "mod_alias.c","mod_userdir.c",NULL };

    ap_hook_translate_name(mva_translate, aszPre, NULL, APR_HOOK_MIDDLE);

}

AP_DECLARE_MODULE(vhost_alias) =

{

    STANDARD20_MODULE_STUFF,

    NULL,                       /* dir config creater */

    NULL,                       /* dir merger --- default is to override */

    mva_create_server_config,   /* server config */

    mva_merge_server_config,    /* merge server configs */

    mva_commands,               /* command apr_table_t */

    register_hooks              /* register hooks */

};