mod_imap.c

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/* 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.
 */

/*
 * This imagemap module started as a port of the original imagemap.c
 * written by Rob McCool (11/13/93 [e-mail]).
 * This version includes the mapping algorithms found in version 1.3
 * of imagemap.c.
 *
 * Contributors to this code include:
 *
 * Kevin Hughes, [e-mail]
 *
 * Eric Haines, [e-mail]
 * "macmartinized" polygon code copyright 1992 by Eric Haines, [e-mail]
 *
 * Randy Terbush, [e-mail]
 * port to Apache module format, "base_uri" and support for relative URLs
 * 
 * James H. Cloos, Jr., [e-mail]
 * Added point datatype, using code in NCSA's version 1.8 imagemap.c
 * program, as distributed with version 1.4.1 of their server.
 * The point code is originally added by Craig Milo Rogers, [e-mail]
 *
 * Nathan Kurz, [e-mail]
 * Rewrite/reorganization.  New handling of default, base and relative URLs.  
 * New Configuration directives:
 *    ImapMenu {none, formatted, semiformatted, unformatted}
 *    ImapDefault {error, nocontent, referer, menu, URL}
 *    ImapBase {map, referer, URL}
 * Support for creating non-graphical menu added.  (backwards compatible):
 *    Old:  directive URL [x,y ...]
 *    New:  directive URL "Menu text" [x,y ...]
 *     or:  directive URL x,y ... "Menu text"
 * Map format and menu concept courtesy Joshua Bell, [e-mail].
 *
 * Mark Cox, [e-mail], Allow relative URLs even when no base specified
 */

#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_main.h"
#include "http_log.h"
#include "util_script.h"

#define IMAP_MAGIC_TYPE "application/x-httpd-imap"
#define MAXVERTS 100
#define X 0
#define Y 1

#define IMAP_MENU_DEFAULT "formatted"
#define IMAP_DEFAULT_DEFAULT "nocontent"
#define IMAP_BASE_DEFAULT "map"

#ifdef SUNOS4
double strtod();                /* SunOS needed this */
#endif

module MODULE_VAR_EXPORT imap_module;

typedef struct {
    char *imap_menu;
    char *imap_default;
    char *imap_base;
} imap_conf_rec;

static void *create_imap_dir_config(pool *p, char *dummy)
{
    imap_conf_rec *icr =
    (imap_conf_rec *) ap_palloc(p, sizeof(imap_conf_rec));

    icr->imap_menu = NULL;
    icr->imap_default = NULL;
    icr->imap_base = NULL;

    return icr;
}

static void *merge_imap_dir_configs(pool *p, void *basev, void *addv)
{
    imap_conf_rec *new = (imap_conf_rec *) ap_pcalloc(p, sizeof(imap_conf_rec));
    imap_conf_rec *base = (imap_conf_rec *) basev;
    imap_conf_rec *add = (imap_conf_rec *) addv;

    new->imap_menu = add->imap_menu ? add->imap_menu : base->imap_menu;
    new->imap_default = add->imap_default ? add->imap_default
                                          : base->imap_default;
    new->imap_base = add->imap_base ? add->imap_base : base->imap_base;

    return new;
}


static const command_rec imap_cmds[] =
{
    {"ImapMenu", ap_set_string_slot,
     (void *) XtOffsetOf(imap_conf_rec, imap_menu), OR_INDEXES, TAKE1,
 "the type of menu generated: none, formatted, semiformatted, unformatted"},
    {"ImapDefault", ap_set_string_slot,
     (void *) XtOffsetOf(imap_conf_rec, imap_default), OR_INDEXES, TAKE1,
     "the action taken if no match: error, nocontent, referer, menu, URL"},
    {"ImapBase", ap_set_string_slot,
     (void *) XtOffsetOf(imap_conf_rec, imap_base), OR_INDEXES, TAKE1,
     "the base for all URL's: map, referer, URL (or start of)"},
    {NULL}
};

static int pointinrect(const double point[2], double coords[MAXVERTS][2])
{
    double max[2], min[2];
    if (coords[0][X] > coords[1][X]) {
        max[0] = coords[0][X];
        min[0] = coords[1][X];
    }
    else {
        max[0] = coords[1][X];
        min[0] = coords[0][X];
    }

    if (coords[0][Y] > coords[1][Y]) {
        max[1] = coords[0][Y];
        min[1] = coords[1][Y];
    }
    else {
        max[1] = coords[1][Y];
        min[1] = coords[0][Y];
    }

    return ((point[X] >= min[0] && point[X] <= max[0]) &&
            (point[Y] >= min[1] && point[Y] <= max[1]));
}

static int pointincircle(const double point[2], double coords[MAXVERTS][2])
{
    double radius1, radius2;

    radius1 = ((coords[0][Y] - coords[1][Y]) * (coords[0][Y] - coords[1][Y]))
        + ((coords[0][X] - coords[1][X]) * (coords[0][X] - coords[1][X]));

    radius2 = ((coords[0][Y] - point[Y]) * (coords[0][Y] - point[Y]))
        + ((coords[0][X] - point[X]) * (coords[0][X] - point[X]));

    return (radius2 <= radius1);
}

#define fmin(a,b) (((a)>(b))?(b):(a))
#define fmax(a,b) (((a)>(b))?(a):(b))

static int pointinpoly(const double point[2], double pgon[MAXVERTS][2])
{
    int i, numverts, crossings = 0;
    double x = point[X], y = point[Y];

    for (numverts = 0; pgon[numverts][X] != -1 && numverts < MAXVERTS;
	numverts++) {
	/* just counting the vertexes */
    }

    for (i = 0; i < numverts; i++) {
        double x1=pgon[i][X];
        double y1=pgon[i][Y];
        double x2=pgon[(i + 1) % numverts][X];
        double y2=pgon[(i + 1) % numverts][Y];
        double d=(y - y1) * (x2 - x1) - (x - x1) * (y2 - y1);

        if ((y1 >= y) != (y2 >= y)) {
	    crossings +=y2 - y1 >= 0 ? d >= 0 : d <= 0;
	}
        if (!d && fmin(x1,x2) <= x && x <= fmax(x1,x2)
	    && fmin(y1,y2) <= y && y <= fmax(y1,y2)) {
	    return 1;
	}
    }
    return crossings & 0x01;
}


static int is_closer(const double point[2], double coords[MAXVERTS][2],
                     double *closest)
{
    double dist_squared = ((point[X] - coords[0][X])
                           * (point[X] - coords[0][X]))
                          + ((point[Y] - coords[0][Y])
                             * (point[Y] - coords[0][Y]));

    if (point[X] < 0 || point[Y] < 0) {
        return (0);          /* don't mess around with negative coordinates */
    }

    if (*closest < 0 || dist_squared < *closest) {
        *closest = dist_squared;
        return (1);          /* if this is the first point or is the closest yet
                                set 'closest' equal to this distance^2 */
    }

    return (0);              /* if it's not the first or closest */

}

static double get_x_coord(const char *args)
{
    char *endptr;               /* we want it non-null */
    double x_coord = -1;        /* -1 is returned if no coordinate is given */

    if (args == NULL) {
        return (-1);            /* in case we aren't passed anything */
    }

    while (*args && !ap_isdigit(*args) && *args != ',') {
        args++;                 /* jump to the first digit, but not past
                                   a comma or end */
    }

    x_coord = strtod(args, &endptr);

    if (endptr > args) {        /* if a conversion was made */
        return (x_coord);
    }

    return (-1);                /* else if no conversion was made,
                                   or if no args was given */
}

static double get_y_coord(const char *args)
{
    char *endptr;               /* we want it non-null */
    char *start_of_y = NULL;
    double y_coord = -1;        /* -1 is returned on error */

    if (args == NULL) {
        return (-1);            /* in case we aren't passed anything */
    }

    start_of_y = strchr(args, ',');     /* the comma */

    if (start_of_y) {

        start_of_y++;           /* start looking at the character after
                                   the comma */

        while (*start_of_y && !ap_isdigit(*start_of_y)) {
            start_of_y++;       /* jump to the first digit, but not
                                   past the end */
	}

        y_coord = strtod(start_of_y, &endptr);

        if (endptr > start_of_y) {
            return (y_coord);
	}
    }

    return (-1);                /* if no conversion was made, or
                                   no comma was found in args */
}


/* See if string has a "quoted part", and if so set *quoted_part to
 * the first character of the quoted part, then hammer a \0 onto the
 * trailing quote, and set *string to point at the first character
 * past the second quote.
 *
 * Otherwise set *quoted_part to NULL, and leave *string alone.
 */
static void read_quoted(char **string, char **quoted_part)
{
    char *strp = *string;

    /* assume there's no quoted part */
    *quoted_part = NULL;

    while (ap_isspace(*strp)) {
        strp++;               	/* go along string until non-whitespace */
    }

    if (*strp == '"') {       	/* if that character is a double quote */
        strp++;               	/* step over it */
	*quoted_part = strp;  	/* note where the quoted part begins */

        while (*strp && *strp != '"') {
	    ++strp;		/* skip the quoted portion */
        }

        *strp = '\0';    	/* end the string with a NUL */

        strp++;               	/* step over the last double quote */
	*string = strp;
    }
}

/*
 * returns the mapped URL or NULL.
 */
static char *imap_url(request_rec *r, const char *base, const char *value)
{
/* translates a value into a URL. */
    int slen, clen;
    char *string_pos = NULL;
    const char *string_pos_const = NULL;
    char *directory = NULL;
    const char *referer = NULL;
    char *my_base;

    if (!strcasecmp(value, "map") || !strcasecmp(value, "menu")) {
	return ap_construct_url(r->pool, r->uri, r);
    }

    if (!strcasecmp(value, "nocontent") || !strcasecmp(value, "error")) {
        return ap_pstrdup(r->pool, value);      /* these are handled elsewhere,
                                                so just copy them */
    }

    if (!strcasecmp(value, "referer")) {
        referer = ap_table_get(r->headers_in, "Referer");
        if (referer && *referer) {
	    return ap_escape_html(r->pool, referer);
        }
        else {
	    /* XXX:  This used to do *value = '\0'; ... which is totally bogus
	     * because it hammers the passed in value, which can be a string
             * constant, or part of a config, or whatever.  Total garbage.
             * This works around that without changing the rest of this
             * code much
             */
            value = "";      /* if 'referer' but no referring page,
                                null the value */
        }
    }

    string_pos_const = value;
    while (ap_isalpha(*string_pos_const)) {
	string_pos_const++;           /* go along the URL from the map
                                         until a non-letter */
    }
    if (*string_pos_const == ':') {
	/* if letters and then a colon (like http:) */
	/* it's an absolute URL, so use it! */
	return ap_pstrdup(r->pool, value);
    }

    if (!base || !*base) {
        if (value && *value) {
	    return ap_pstrdup(r->pool, value); /* no base: use what is given */
        }
	/* no base, no value: pick a simple default */
	return ap_construct_url(r->pool, "/", r);
    }

    /* must be a relative URL to be combined with base */
    if (strchr(base, '/') == NULL && (!strncmp(value, "../", 3)
        || !strcmp(value, ".."))) {
        ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,
                    "invalid base directive in map file: %s", r->uri);
        return NULL;
    }
    my_base = ap_pstrdup(r->pool, base);
    string_pos = my_base;
    while (*string_pos) {
        if (*string_pos == '/' && *(string_pos + 1) == '/') {
            string_pos += 2;    /* if there are two slashes, jump over them */
            continue;
        }
        if (*string_pos == '/') {       /* the first single slash */
            if (value[0] == '/') {
                *string_pos = '\0';
            }                   /* if the URL from the map starts from root,
                                   end the base URL string at the first single
                                   slash */
            else {
                directory = string_pos;         /* save the start of
                                                   the directory portion */

                string_pos = strrchr(string_pos, '/');  /* now reuse
                                                           string_pos */
                string_pos++;   /* step over that last slash */
                *string_pos = '\0';
            }                   /* but if the map url is relative, leave the
                                   slash on the base (if there is one) */
            break;
        }
        string_pos++;           /* until we get to the end of my_base without
                                   finding a slash by itself */
    }

    while (!strncmp(value, "../", 3) || !strcmp(value, "..")) {

        if (directory && (slen = strlen(directory))) {

            /* for each '..',  knock a directory off the end 
               by ending the string right at the last slash.
               But only consider the directory portion: don't eat
               into the server name.  And only try if a directory
               portion was found */

            clen = slen - 1;

            while ((slen - clen) == 1) {

                if ((string_pos = strrchr(directory, '/'))) {
                    *string_pos = '\0';
		}
                clen = strlen(directory);
                if (clen == 0) {
                    break;
		}
            }

            value += 2;         /* jump over the '..' that we found in the
                                   value */
        }
        else if (directory) {
            ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,
                        "invalid directory name in map file: %s", r->uri);
            return NULL;
        }

        if (!strncmp(value, "/../", 4) || !strcmp(value, "/..")) {
            value++;            /* step over the '/' if there are more '..'
                                   to do.  This way, we leave the starting
                                   '/' on value after the last '..', but get
                                   rid of it otherwise */
	}

    }                           /* by this point, value does not start
                                   with '..' */