KTOR-6960 Add UnixDomainSocket support for iOS/tvOS/watchOS

[05nelsonm]

Subsystem
Module ktor-network

Motivation
https://youtrack.jetbrains.com/issue/KTOR-6960/Unix-Domain-Socket-Support-for-iOS-tvOS-watchOS

Solution
Adds cinterop definition to include sys/un.h headers for iOS/tvOS/watchOS giving access to sockaddr_un struct for given SDKs, and implements pack/unpack sockaddr_un functions

[e5l]

Hey @05nelsonm, thanks for the PR. Let me run a CI check

[Thomas-Vos]

I think unix sockets do not work on watchOS. Did you actually try this on a real watch instead of a simulator? See: https://developer.apple.com/documentation/technotes/tn3135-low-level-networking-on-watchos

So I guess it is better to revert the changes for watchOS to avoid confusion for other users thinking Ktor supports it.

[e5l]

@Thomas-Vos, it looks so, thank you for noticing!

@05nelsonm, could you tell me if you have a chance to check?

[05nelsonm]

I tend not to believe apple's documentation over their header files which are all identical for each platform (device or simulator).

admin@Mac_Mini /Applications % xcodebuild -version

Xcode 15.0.1
Build version 15A507

{PLATFORM}.sdk/usr/include/sys/un.h

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)un.h	8.3 (Berkeley) 2/19/95
 */

#ifndef _SYS_UN_H_
#define _SYS_UN_H_

#include <sys/appleapiopts.h>
#include <sys/cdefs.h>
#include <sys/_types.h>

/* [XSI] The sa_family_t type shall be defined as described in <sys/socket.h> */
#include <sys/_types/_sa_family_t.h>

/*
 * [XSI] Definitions for UNIX IPC domain.
 */
struct  sockaddr_un {
	unsigned char   sun_len;        /* sockaddr len including null */
	sa_family_t     sun_family;     /* [XSI] AF_UNIX */
	char            sun_path[104];  /* [XSI] path name (gag) */
};

#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)

/* Level number of get/setsockopt for local domain sockets */
#define SOL_LOCAL               0

/* Socket options. */
#define LOCAL_PEERCRED          0x001           /* retrieve peer credentials */
#define LOCAL_PEERPID           0x002           /* retrieve peer pid */
#define LOCAL_PEEREPID          0x003           /* retrieve eff. peer pid */
#define LOCAL_PEERUUID          0x004           /* retrieve peer UUID */
#define LOCAL_PEEREUUID         0x005           /* retrieve eff. peer UUID */
#define LOCAL_PEERTOKEN         0x006           /* retrieve peer audit token */

#endif  /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */



#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
/* actual length of an initialized sockaddr_un */
#define SUN_LEN(su) \
	(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
#endif  /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */


#endif /* !_SYS_UN_H_ */

I believe the failures are attributed to an error in the build.gradle.kts file which should check HostManager.hostIsMac before adding the definition.

Will rebase and fix!