/* $OpenBSD$ */

/*

 * 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);

    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);

}