/usr/share/racket/collects/unstable/socket.rkt is in racket-common 6.1-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | #lang racket/base
;; Support for connecting to UNIX domain sockets.
#|
References:
linux (64):
Linux Standard Base Core Specification 4.1
macosx (64):
/usr/include/i386/_types.h: __darwin_socklen_t
/usr/include/sys/socket.h: AF_UNIX
/usr/include/sys/un.h: struct sockaddr_un
|#
(require racket/contract
(rename-in ffi/unsafe (-> -->))
ffi/unsafe/define
ffi/file
unstable/error)
(provide
(contract-out
[unix-socket-available?
boolean?]
[unix-socket-connect
(-> unix-socket-path? (values input-port? output-port?))]
[unix-socket-path?
(-> any/c boolean?)]))
;; Data structures and error handling code differs between the platforms.
(define platform
(cond
[(eq? (system-type 'os) 'macosx)
'macosx]
[(regexp-match? #rx"^Linux" (system-type 'machine))
'linux]
[else
#f]))
(define unix-socket-available?
(and platform #t))
(define AF-UNIX 1)
(define SOCK-STREAM 1)
(define UNIX-PATH-MAX
(case platform
[(linux) 108]
[else 104]))
(define _socklen_t
(case platform
[(linux) _uint]
[else _uint32]))
(define-cstruct _linux_sockaddr_un
([sun_family _ushort]
[sun_path (make-array-type _byte UNIX-PATH-MAX)]))
(define-cstruct _macosx_sockaddr_un
([sun_len _ubyte]
[sun_family _ubyte]
[sun_path (make-array-type _byte UNIX-PATH-MAX)]))
(define _sockaddr_un-pointer
(case platform
[(linux) _linux_sockaddr_un-pointer]
[(macosx) _macosx_sockaddr_un-pointer]
[else _pointer]))
(define-ffi-definer define-libc (ffi-lib #f)
#:default-make-fail make-not-available)
(define-libc socket
(_fun #:save-errno 'posix
_int _int _int --> _int))
(define-libc connect
(_fun #:save-errno 'posix
_int _sockaddr_un-pointer _int --> _int))
(define-libc close
(_fun #:save-errno 'posix
_int --> _int))
(define-libc scheme_make_fd_output_port
(_fun _int _racket _bool _bool _bool --> _racket))
(define strerror-name
(case platform
[(linux) "__xpg_strerror_r"]
[else "strerror_r"]))
(define strerror_r
(get-ffi-obj strerror-name #f
(_fun (errno) ::
(errno : _int)
(buf : _bytes = (make-bytes 1000))
(buf-len : _size = (bytes-length buf))
--> _void
--> (cast buf _bytes _string/locale))
(lambda ()
(lambda (errno) #f))))
(define (unix-socket-path? v)
(and (unix-socket-path->bytes v) #t))
(define (unix-socket-path->bytes path)
(if (path-string? path)
;; On all platforms, normal path of up to UNIX-PATH-MAX bytes after
;; conversion to absolute is considered valid and shall be accepted.
(let ([bstr (path->bytes (cleanse-path (path->complete-path path)))])
(and (<= (bytes-length bstr) UNIX-PATH-MAX) bstr))
;; On Linux, paths may be in so-called abstract namespace where they
;; start with #\nul and do not have a corresponding socket file.
;; We accept such paths only as byte strings because we don't know
;; the correct encoding.
(and (eq? platform 'linux)
(bytes? path)
(> (bytes-length path) 0)
(<= (bytes-length path) UNIX-PATH-MAX)
(= (bytes-ref path 0) 0)
path)))
(define (make-sockaddr path-bytes)
(case platform
[(linux)
(make-linux_sockaddr_un AF-UNIX path-bytes)]
[(macosx)
(make-macosx_sockaddr_un (bytes-length path-bytes) AF-UNIX path-bytes)]))
(define (unix-socket-connect path)
(unless platform
(error* 'unix-socket-connect
"unix domain sockets are not supported on this platform"))
(when (path-string? path)
(security-guard-check-file 'unix-socket-connect path '(read write)))
(let* ([path-bytes (unix-socket-path->bytes path)]
[sockaddr (make-sockaddr path-bytes)]
[addrlen (+ (ctype-sizeof _ushort) (bytes-length path-bytes))]
[socket-fd (socket AF-UNIX SOCK-STREAM 0)])
(unless (positive? socket-fd)
(let ([errno (saved-errno)])
(error* 'unix-socket-connect
"failed to create socket"
"errno" errno
'("error" maybe) (strerror_r errno))))
(unless (zero? (connect socket-fd sockaddr addrlen))
(close socket-fd)
(let ([errno (saved-errno)])
(error* 'unix-socket-connect
"failed to connect socket"
'("path" value) path
"errno" errno
'("error" maybe) (strerror_r errno))))
(with-handlers ([(lambda (e) #t)
(lambda (exn)
(close socket-fd)
(raise exn))])
(scheme_make_fd_output_port socket-fd 'unix-socket #f #f #t))))
|