/* $OpenBSD$ */

/*
* Copyright (c) 2021 Dallas Lyons <[email protected]>
*
* 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);
               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);
}