/*      $OpenBSD: expand.c,v 1.32 2021/06/14 17:58:15 eric Exp $        */

/*
 * Copyright (c) 2009 Gilles Chehade <gilles@poolp.org>
 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdlib.h>
#include <string.h>

#include "smtpd.h"

static const char *expandnode_info(struct expandnode *);

struct expandnode *
expand_lookup(struct expand *expand, struct expandnode *key)
{
        return RB_FIND(expandtree, &expand->tree, key);
}

int
expand_to_text(struct expand *expand, char *buf, size_t sz)
{
        struct expandnode *xn;

        buf[0] = '\0';

        RB_FOREACH(xn, expandtree, &expand->tree) {
                if (buf[0])
                        (void)strlcat(buf, ", ", sz);
                if (strlcat(buf, expandnode_to_text(xn), sz) >= sz)
                        return 0;
        }

        return 1;
}

void
expand_insert(struct expand *expand, struct expandnode *node)
{
        struct expandnode *xn;

        node->rule = expand->rule;
        node->parent = expand->parent;

        log_trace(TRACE_EXPAND, "expand: %p: expand_insert() called for %s",
            expand, expandnode_info(node));
        if (node->type == EXPAND_USERNAME &&
            expand->parent &&
            expand->parent->type == EXPAND_USERNAME &&
            !strcmp(expand->parent->u.user, node->u.user)) {
                log_trace(TRACE_EXPAND, "expand: %p: setting sameuser = 1",
                    expand);
                node->sameuser = 1;
        }

        if (expand_lookup(expand, node)) {
                log_trace(TRACE_EXPAND, "expand: %p: node found, discarding",
                        expand);
                return;
        }

        xn = xmemdup(node, sizeof *xn);
        xn->rule = expand->rule;
        xn->parent = expand->parent;
        if (xn->parent)
                xn->depth = xn->parent->depth + 1;
        else
                xn->depth = 0;
        RB_INSERT(expandtree, &expand->tree, xn);
        if (expand->queue)
                TAILQ_INSERT_TAIL(expand->queue, xn, tq_entry);
        expand->nb_nodes++;
        log_trace(TRACE_EXPAND, "expand: %p: inserted node %p", expand, xn);
}

void
expand_clear(struct expand *expand)
{
        struct expandnode *xn;

        log_trace(TRACE_EXPAND, "expand: %p: clearing expand tree", expand);
        if (expand->queue)
                while ((xn = TAILQ_FIRST(expand->queue)))
                        TAILQ_REMOVE(expand->queue, xn, tq_entry);

        while ((xn = RB_ROOT(&expand->tree)) != NULL) {
                RB_REMOVE(expandtree, &expand->tree, xn);
                free(xn);
        }
}

void
expand_free(struct expand *expand)
{
        expand_clear(expand);

        log_trace(TRACE_EXPAND, "expand: %p: freeing expand tree", expand);
        free(expand);
}

int
expand_cmp(struct expandnode *e1, struct expandnode *e2)
{
        struct expandnode *p1, *p2;
        int                r;

        if (e1->type < e2->type)
                return -1;
        if (e1->type > e2->type)
                return 1;
        if (e1->sameuser < e2->sameuser)
                return -1;
        if (e1->sameuser > e2->sameuser)
                return 1;
        if (e1->realuser < e2->realuser)
                return -1;
        if (e1->realuser > e2->realuser)
                return 1;

        r = memcmp(&e1->u, &e2->u, sizeof(e1->u));
        if (r)
                return (r);

        if (e1->parent == e2->parent)
                return (0);

        if (e1->parent == NULL)
                return (-1);
        if (e2->parent == NULL)
                return (1);

        /*
         * The same node can be expanded in for different dest context.
         * Wen need to distinguish between those.
         */
        for(p1 = e1->parent; p1->type != EXPAND_ADDRESS; p1 = p1->parent)
                ;
        for(p2 = e2->parent; p2->type != EXPAND_ADDRESS; p2 = p2->parent)
                ;
        if (p1 < p2)
                return (-1);
        if (p1 > p2)
                return (1);

        if (e1->type != EXPAND_FILENAME && e1->type != EXPAND_FILTER)
                return (0);

        /*
         * For external delivery, we need to distinguish between users.
         * If we can't find a username, we assume it is _smtpd.
         */
        for(p1 = e1->parent; p1 && p1->type != EXPAND_USERNAME; p1 = p1->parent)
                ;
        for(p2 = e2->parent; p2 && p2->type != EXPAND_USERNAME; p2 = p2->parent)
                ;
        if (p1 < p2)
                return (-1);
        if (p1 > p2)
                return (1);

        return (0);
}

static int
expand_line_split(char **line, char **ret)
{
        static char     buffer[LINE_MAX];
        int             esc, dq, sq;
        size_t          i;
        char           *s;

        memset(buffer, 0, sizeof buffer);
        esc = dq = sq = 0;
        i = 0;
        for (s = *line; (*s) && (i < sizeof(buffer)); ++s) {
                if (esc) {
                        buffer[i++] = *s;
                        esc = 0;
                        continue;
                }
                if (*s == '\\') {
                        esc = 1;
                        continue;
                }
                if (*s == ',' && !dq && !sq) {
                        *ret = buffer;
                        *line = s+1;
                        return (1);
                }

                buffer[i++] = *s;
                esc = 0;

                if (*s == '"' && !sq)
                        dq ^= 1;
                if (*s == '\'' && !dq)
                        sq ^= 1;
        }

        if (esc || dq || sq || i == sizeof(buffer))
                return (-1);

        *ret = buffer;
        *line = s;
        return (i ? 1 : 0);
}

int
expand_line(struct expand *expand, const char *s, int do_includes)
{
        struct expandnode       xn;
        char                    buffer[LINE_MAX];
        char                   *p, *subrcpt;
        int                     ret;

        memset(buffer, 0, sizeof buffer);
        if (strlcpy(buffer, s, sizeof buffer) >= sizeof buffer)
                return 0;

        p = buffer;
        while ((ret = expand_line_split(&p, &subrcpt)) > 0) {
                subrcpt = strip(subrcpt);
                if (subrcpt[0] == '\0')
                        continue;
                if (!text_to_expandnode(&xn, subrcpt))
                        return 0;
                if (!do_includes)
                        if (xn.type == EXPAND_INCLUDE)
                                continue;
                expand_insert(expand, &xn);
        }

        if (ret >= 0)
                return 1;

        /* expand_line_split() returned < 0 */
        return 0;
}

static const char *
expandnode_info(struct expandnode *e)
{
        static char     buffer[1024];
        const char     *type = NULL;
        const char     *value = NULL;
        char            tmp[64];

        switch (e->type) {
        case EXPAND_FILTER:
                type = "filter";
                break;
        case EXPAND_FILENAME:
                type = "filename";
                break;
        case EXPAND_INCLUDE:
                type = "include";
                break;
        case EXPAND_USERNAME:
                type = "username";
                break;
        case EXPAND_ADDRESS:
                type = "address";
                break;
        case EXPAND_ERROR:
                type = "error";
                break;
        case EXPAND_INVALID:
        default:
                return NULL;
        }

        if ((value = expandnode_to_text(e)) == NULL)
                return NULL;

        (void)strlcpy(buffer, type, sizeof buffer);
        (void)strlcat(buffer, ":", sizeof buffer);
        if (strlcat(buffer, value, sizeof buffer) >= sizeof buffer)
                return NULL;

        (void)snprintf(tmp, sizeof(tmp), "[parent=%p", e->parent);
        if (strlcat(buffer, tmp, sizeof buffer) >= sizeof buffer)
                return NULL;

        (void)snprintf(tmp, sizeof(tmp), ", rule=%p", e->rule);
        if (strlcat(buffer, tmp, sizeof buffer) >= sizeof buffer)
                return NULL;

        if (e->rule) {
                (void)snprintf(tmp, sizeof(tmp), ", dispatcher=%p", e->rule->dispatcher);
                if (strlcat(buffer, tmp, sizeof buffer) >= sizeof buffer)
                        return NULL;
        }

        if (strlcat(buffer, "]", sizeof buffer) >= sizeof buffer)
                return NULL;

        return buffer;
}

RB_GENERATE(expandtree, expandnode, entry, expand_cmp);