/* $OpenBSD: cmd-server-access.c,v 1.6 2026/06/09 12:58:40 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 <grp.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 = { "adglrw", 0, 1, NULL },
        .usage = "[-adglrw] " CMD_TARGET_PANE_USAGE " [user|group]",

        .flags = CMD_CLIENT_CANFAIL,
        .exec = cmd_server_access_exec
};

static enum cmd_retval
cmd_server_access_deny(struct cmdq_item *item, id_t id, int flags,
    const char *type, const char *name)
{
        if (!server_acl_find(id, flags)) {
                cmdq_error(item, "%s %s not found", type, name);
                return (CMD_RETURN_ERROR);
        }
        server_acl_deny(id, flags);
        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            *arg;
        const char      *name = NULL, *type;
        struct passwd   *pw;
        struct group    *gr;
        id_t             id;
        int              flags = 0;

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

        arg = format_single(item, args_string(args, 0), c, NULL, NULL, NULL);
        if (args_has(args, 'g')) {
                type = "group";
                if ((gr = getgrnam(arg)) != NULL) {
                        id = gr->gr_gid;
                        name = gr->gr_name;
                        flags |= SERVER_ACL_IS_GROUP;
                }
        } else {
                type = "user";
                if ((pw = getpwnam(arg)) != NULL) {
                        id = pw->pw_uid;
                        name = pw->pw_name;
                }
        }
        if (name == NULL) {
                cmdq_error(item, "unknown %s: %s", type, arg);
                free(arg);
                return (CMD_RETURN_ERROR);
        }
        free(arg);

        if ((~flags & SERVER_ACL_IS_GROUP) && (id == 0 || id == getuid())) {
                cmdq_error(item, "%s owns the server, can't change access",
                    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, id, flags, type, name));
        if (args_has(args, 'a')) {
                if (server_acl_find(id, flags)) {
                        cmdq_error(item, "%s %s is already added", type, name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_allow(id, flags);
                /* 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 the entry does not exist. */
                if (!server_acl_find(id, flags))
                        server_acl_allow(id, flags);
        }

        if (args_has(args, 'w')) {
                if (!server_acl_find(id, flags)) {
                        cmdq_error(item, "%s %s not found", type, name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_allow_write(id, flags);
                return (CMD_RETURN_NORMAL);
        }

        if (args_has(args, 'r')) {
                if (!server_acl_find(id, flags)) {
                        cmdq_error(item, "%s %s not found", type, name);
                        return (CMD_RETURN_ERROR);
                }
                server_acl_deny_write(id, flags);
                return (CMD_RETURN_NORMAL);
        }

        return (CMD_RETURN_NORMAL);
}