/* $OpenBSD: cmd-server-access.c,v 1.4 2026/02/23 08:54:56 nicm Exp $ */

/*
 * Copyright (c) 2021 Dallas Lyons <dallasdlyons@gmail.com>
 *
 * 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 MIND, 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 <sys/stat.h>
#include <sys/types.h>

#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "tmux.h"

/*
 * Controls access to session.
 */

static enum cmd_retval cmd_server_access_exec(struct cmd *, struct cmdq_item *);

const struct cmd_entry cmd_server_access_entry = {
        .name = "server-access",
        .alias = NULL,

        .args = { "adlrw", 0, 1, NULL },
        .usage = "[-adlrw] " CMD_TARGET_PANE_USAGE " [user]",

        .flags = CMD_CLIENT_CANFAIL,
        .exec = cmd_server_access_exec
};

static enum cmd_retval
cmd_server_access_deny(struct cmdq_item *item, struct passwd *pw)
{
        struct client           *loop;
        struct server_acl_user  *user;
        uid_t                    uid;

        if ((user = server_acl_user_find(pw->pw_uid)) == NULL) {
                cmdq_error(item, "user %s not found", pw->pw_name);
                return (CMD_RETURN_ERROR);
        }
        TAILQ_FOREACH(loop, &clients, entry) {
                uid = proc_get_peer_uid(loop->peer);
                if (uid == server_acl_get_uid(user)) {
                        loop->exit_message = xstrdup("access not allowed");
                        loop->flags |= CLIENT_EXIT;
                }
        }
        server_acl_user_deny(pw->pw_uid);

        return (CMD_RETURN_NORMAL);
}

static enum cmd_retval
cmd_server_access_exec(struct cmd *self, struct cmdq_item *item)
{

        struct args     *args = cmd_get_args(self);
        struct client   *c = cmdq_get_target_client(item);
        char            *name;
        struct passwd   *pw = NULL;

        if (args_has(args, 'l')) {
                server_acl_display(item);
                return (CMD_RETURN_NORMAL);
        }
        if (args_count(args) == 0) {
                cmdq_error(item, "missing user argument");
                return (CMD_RETURN_ERROR);
        }

        name = format_single(item, args_string(args, 0), c, NULL, NULL, NULL);
        if (*name != '\0')
                pw = getpwnam(name);
        if (pw == NULL) {
                cmdq_error(item, "unknown user: %s", name);
                free(name);
                return (CMD_RETURN_ERROR);
        }
        free(name);

        if (pw->pw_uid == 0 || pw->pw_uid == getuid()) {
                cmdq_error(item, "%s owns the server, can't change access",
                    pw->pw_name);
                return (CMD_RETURN_ERROR);
        }

        if (args_has(args, 'a') && args_has(args, 'd')) {
                cmdq_error(item, "-a and -d cannot be used together");
                return (CMD_RETURN_ERROR);
        }
        if (args_has(args, 'w') && args_has(args, 'r')) {
                cmdq_error(item, "-r and -w cannot be used together");
                return (CMD_RETURN_ERROR);
        }

        if (args_has(args, 'd'))
                return (cmd_server_access_deny(item, pw));
        if (args_has(args, 'a')) {
                if (server_acl_user_find(pw->pw_uid) != NULL) {
                        cmdq_error(item, "user %s is already added",
                            pw->pw_name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_user_allow(pw->pw_uid);
                /* Do not return - allow -r or -w with -a. */
        } else if (args_has(args, 'r') || args_has(args, 'w')) {
                /* -r or -w implies -a if user does not exist. */
                if (server_acl_user_find(pw->pw_uid) == NULL)
                        server_acl_user_allow(pw->pw_uid);
        }

        if (args_has(args, 'w')) {
                if (server_acl_user_find(pw->pw_uid) == NULL) {
                        cmdq_error(item, "user %s not found", pw->pw_name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_user_allow_write(pw->pw_uid);
                return (CMD_RETURN_NORMAL);
        }

        if (args_has(args, 'r')) {
                if (server_acl_user_find(pw->pw_uid) == NULL) {
                        cmdq_error(item, "user %s not found", pw->pw_name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_user_deny_write(pw->pw_uid);
                return (CMD_RETURN_NORMAL);
        }

        return (CMD_RETURN_NORMAL);
}