Mirror of GNU Guix
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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix build syscalls)
#:use-module (system foreign)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-11)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 regex)
#:use-module (ice-9 match)
#:use-module (ice-9 ftw)
#:export (MS_RDONLY
MS_NOSUID
MS_NODEV
MS_NOEXEC
MS_REMOUNT
MS_BIND
MS_MOVE
MS_STRICTATIME
MNT_FORCE
MNT_DETACH
MNT_EXPIRE
UMOUNT_NOFOLLOW
restart-on-EINTR
mount
umount
mount-points
swapon
swapoff
file-system?
file-system-type
file-system-block-size
file-system-block-count
file-system-blocks-free
file-system-blocks-available
file-system-file-count
file-system-free-file-nodes
file-system-identifier
file-system-maximum-name-length
file-system-fragment-size
file-system-mount-flags
statfs
processes
mkdtemp!
fdatasync
pivot-root
fcntl-flock
CLONE_CHILD_CLEARTID
CLONE_CHILD_SETTID
CLONE_NEWNS
CLONE_NEWUTS
CLONE_NEWIPC
CLONE_NEWUSER
CLONE_NEWPID
CLONE_NEWNET
clone
setns
PF_PACKET
AF_PACKET
IFF_UP
IFF_BROADCAST
IFF_LOOPBACK
all-network-interface-names
network-interface-names
network-interface-flags
network-interface-netmask
loopback-network-interface?
network-interface-address
set-network-interface-flags
set-network-interface-address
set-network-interface-netmask
set-network-interface-up
configure-network-interface
add-network-route/gateway
delete-network-route
interface?
interface-name
interface-flags
interface-address
interface-netmask
interface-broadcast-address
network-interfaces
termios?
termios-input-flags
termios-output-flags
termios-control-flags
termios-local-flags
termios-line-discipline
termios-control-chars
termios-input-speed
termios-output-speed
local-flags
tcsetattr-action
tcgetattr
tcsetattr
window-size?
window-size-rows
window-size-columns
window-size-x-pixels
window-size-y-pixels
terminal-window-size
terminal-columns))
;;; Commentary:
;;;
;;; This module provides bindings to libc's syscall wrappers. It uses the
;;; FFI, and thus requires a dynamically-linked Guile. (For statically-linked
;;; Guile, we instead apply 'guile-linux-syscalls.patch'.)
;;;
;;; Code:
;;;
;;; Packed structures.
;;;
(define-syntax sizeof*
;; XXX: This duplicates 'compile-time-value'.
(syntax-rules (int128 array)
((_ int128)
16)
((_ (array type n))
(* (sizeof* type) n))
((_ type)
(let-syntax ((v (lambda (s)
(let ((val (sizeof type)))
(syntax-case s ()
(_ val))))))
v))))
(define-syntax alignof*
;; XXX: This duplicates 'compile-time-value'.
(syntax-rules (int128 array)
((_ int128)
16)
((_ (array type n))
(alignof* type))
((_ type)
(let-syntax ((v (lambda (s)
(let ((val (alignof type)))
(syntax-case s ()
(_ val))))))
v))))
(define-syntax align ;as found in (system foreign)
(syntax-rules (~)
"Add to OFFSET whatever it takes to get proper alignment for TYPE."
((_ offset (type ~ endianness))
(align offset type))
((_ offset type)
(1+ (logior (1- offset) (1- (alignof* type)))))))
(define-syntax type-size
(syntax-rules (~)
((_ (type ~ order))
(sizeof* type))
((_ type)
(sizeof* type))))
(define-syntax struct-alignment
(syntax-rules ()
"Compute the alignment for the aggregate made of TYPES at OFFSET. The
result is the alignment of the \"most strictly aligned component\"."
((_ offset types ...)
(max (align offset types) ...))))
(define-syntax struct-size
(syntax-rules ()
"Return the size in bytes of the structure made of TYPES."
((_ offset (types-processed ...))
;; The SysV ABI P.S. says: "Aggregates (structures and arrays) and unions
;; assume the alignment of their most strictly aligned component." As an
;; example, a struct such as "int32, int16" has size 8, not 6.
(1+ (logior (1- offset)
(1- (struct-alignment offset types-processed ...)))))
((_ offset (types-processed ...) type0 types ...)
(struct-size (+ (type-size type0) (align offset type0))
(type0 types-processed ...)
types ...))))
(define-syntax write-type
(syntax-rules (~ array *)
((_ bv offset (type ~ order) value)
(bytevector-uint-set! bv offset value
(endianness order) (sizeof* type)))
((_ bv offset (array type n) value)
(let loop ((i 0)
(value value)
(o offset))
(unless (= i n)
(match value
((head . tail)
(write-type bv o type head)
(loop (+ 1 i) tail (+ o (sizeof* type))))))))
((_ bv offset '* value)
(bytevector-uint-set! bv offset (pointer-address value)
(native-endianness) (sizeof* '*)))
((_ bv offset type value)
(bytevector-uint-set! bv offset value
(native-endianness) (sizeof* type)))))
(define-syntax write-types
(syntax-rules ()
((_ bv offset () ())
#t)
((_ bv offset (type0 types ...) (field0 fields ...))
(begin
(write-type bv (align offset type0) type0 field0)
(write-types bv
(+ (align offset type0) (type-size type0))
(types ...) (fields ...))))))
(define-syntax read-type
(syntax-rules (~ array quote *)
((_ bv offset '*)
(make-pointer (bytevector-uint-ref bv offset
(native-endianness)
(sizeof* '*))))
((_ bv offset (type ~ order))
(bytevector-uint-ref bv offset
(endianness order) (sizeof* type)))
((_ bv offset (array type n))
(unfold (lambda (i) (= i n))
(lambda (i)
(read-type bv (+ offset (* i (sizeof* type))) type))
1+
0))
((_ bv offset type)
(bytevector-uint-ref bv offset
(native-endianness) (sizeof* type)))))
(define-syntax read-types
(syntax-rules ()
((_ return bv offset () (values ...))
(return values ...))
((_ return bv offset (type0 types ...) (values ...))
(read-types return
bv
(+ (align offset type0) (type-size type0))
(types ...)
(values ... (read-type bv
(align offset type0)
type0))))))
(define-syntax define-c-struct-macro
(syntax-rules ()
"Define NAME as a macro that can be queried to get information about the C
struct it represents. In particular:
(NAME field-offset FIELD)
returns the offset in bytes of FIELD within the C struct represented by NAME."
((_ name ((fields types) ...))
(define-c-struct-macro name
(fields ...) 0 ()
((fields types) ...)))
((_ name (fields ...) offset (clauses ...) ((field type) rest ...))
(define-c-struct-macro name
(fields ...)
(+ (align offset type) (type-size type))
(clauses ... ((_ field-offset field) (align offset type)))
(rest ...)))
((_ name (fields ...) offset (clauses ...) ())
(define-syntax name
(syntax-rules (field-offset fields ...)
clauses ...)))))
(define-syntax define-c-struct
(syntax-rules ()
"Define SIZE as the size in bytes of the C structure made of FIELDS. READ
as a deserializer and WRITE! as a serializer for the C structure with the
given TYPES. READ uses WRAP-FIELDS to return its value."
((_ name size wrap-fields read write! (fields types) ...)
(begin
(define-c-struct-macro name
((fields types) ...))
(define size
(struct-size 0 () types ...))
(define (write! bv offset fields ...)
(write-types bv offset (types ...) (fields ...)))
(define* (read bv #:optional (offset 0))
(read-types wrap-fields bv offset (types ...) ()))))))
(define-syntax-rule (c-struct-field-offset type field)
"Return the offset in BYTES of FIELD within TYPE, where TYPE is a C struct
defined with 'define-c-struct' and FIELD is a field identifier. An
expansion-time error is raised if FIELD does not exist in TYPE."
(type field-offset field))
;;;
;;; FFI.
;;;
(define %libc-errno-pointer
;; Glibc's 'errno' pointer, for use with Guile < 2.0.12.
(let ((errno-loc (false-if-exception
(dynamic-func "__errno_location" (dynamic-link)))))
(and errno-loc
(let ((proc (pointer->procedure '* errno-loc '())))
(proc)))))
(define errno ;for Guile < 2.0.12
(if %libc-errno-pointer
(let ((bv (pointer->bytevector %libc-errno-pointer (sizeof int))))
(lambda ()
"Return the current errno."
;; XXX: We assume that nothing changes 'errno' while we're doing all this.
;; In particular, that means that no async must be running here.
;; Use one of the fixed-size native-ref procedures because they are
;; optimized down to a single VM instruction, which reduces the risk
;; that we fiddle with 'errno' (needed on Guile 2.0.5, libc 2.11.)
(let-syntax ((ref (lambda (s)
(syntax-case s ()
((_ bv)
(case (sizeof int)
((4)
#'(bytevector-s32-native-ref bv 0))
((8)
#'(bytevector-s64-native-ref bv 0))
(else
(error "unsupported 'int' size"
(sizeof int)))))))))
(ref bv))))
(lambda () 0)))
(define (call-with-restart-on-EINTR thunk)
(let loop ()
(catch 'system-error
thunk
(lambda args
(if (= (system-error-errno args) EINTR)
(loop)
(apply throw args))))))
(define-syntax-rule (restart-on-EINTR expr)
"Evaluate EXPR and restart upon EINTR. Return the value of EXPR."
(call-with-restart-on-EINTR (lambda () expr)))
(define (syscall->procedure return-type name argument-types)
"Return a procedure that wraps the C function NAME using the dynamic FFI,
and that returns two values: NAME's return value, and errno.
If an error occurs while creating the binding, defer the error report until
the returned procedure is called."
(catch #t
(lambda ()
(let ((ptr (dynamic-func name (dynamic-link))))
;; The #:return-errno? facility was introduced in Guile 2.0.12.
;; Support older versions of Guile by catching 'wrong-number-of-args'.
(catch 'wrong-number-of-args
(lambda ()
(pointer->procedure return-type ptr argument-types
#:return-errno? #t))
(lambda (key . rest)
(let ((proc (pointer->procedure return-type ptr argument-types)))
(lambda args
(let ((result (apply proc args))
(err (errno)))
(values result err))))))))
(lambda args
(lambda _
(error (format #f "~a: syscall->procedure failed: ~s"
name args))))))
;;;
;;; File systems.
;;;
(define (augment-mtab source target type options)
"Augment /etc/mtab with information about the given mount point."
(let ((port (open-file "/etc/mtab" "a")))
(format port "~a ~a ~a ~a 0 0~%"
source target type (or options "rw"))
(close-port port)))
(define (read-mtab port)
"Read an mtab-formatted file from PORT, returning a list of tuples."
(let loop ((result '()))
(let ((line (read-line port)))
(if (eof-object? line)
(reverse result)
(loop (cons (string-tokenize line) result))))))
(define (remove-from-mtab target)
"Remove mount point TARGET from /etc/mtab."
(define entries
(remove (match-lambda
((device mount-point type options freq passno)
(string=? target mount-point))
(_ #f))
(call-with-input-file "/etc/mtab" read-mtab)))
(call-with-output-file "/etc/mtab"
(lambda (port)
(for-each (match-lambda
((device mount-point type options freq passno)
(format port "~a ~a ~a ~a ~a ~a~%"
device mount-point type options freq passno)))
entries))))
;; Linux mount flags, from libc's <sys/mount.h>.
(define MS_RDONLY 1)
(define MS_NOSUID 2)
(define MS_NODEV 4)
(define MS_NOEXEC 8)
(define MS_REMOUNT 32)
(define MS_BIND 4096)
(define MS_MOVE 8192)
(define MS_STRICTATIME 16777216)
(define MNT_FORCE 1)
(define MNT_DETACH 2)
(define MNT_EXPIRE 4)
(define UMOUNT_NOFOLLOW 8)
(define mount
(let ((proc (syscall->procedure int "mount" `(* * * ,unsigned-long *))))
(lambda* (source target type #:optional (flags 0) options
#:key (update-mtab? #f))
"Mount device SOURCE on TARGET as a file system TYPE. Optionally, FLAGS
may be a bitwise-or of the MS_* <sys/mount.h> constants, and OPTIONS may be a
string. When FLAGS contains MS_REMOUNT, SOURCE and TYPE are ignored. When
UPDATE-MTAB? is true, update /etc/mtab. Raise a 'system-error' exception on
error."
(let-values (((ret err)
(proc (if source
(string->pointer source)
%null-pointer)
(string->pointer target)
(if type
(string->pointer type)
%null-pointer)
flags
(if options
(string->pointer options)
%null-pointer))))
(unless (zero? ret)
(throw 'system-error "mount" "mount ~S on ~S: ~A"
(list source target (strerror err))
(list err)))
(when update-mtab?
(augment-mtab source target type options))))))
(define umount
(let ((proc (syscall->procedure int "umount2" `(* ,int))))
(lambda* (target #:optional (flags 0)
#:key (update-mtab? #f))
"Unmount TARGET. Optionally FLAGS may be one of the MNT_* or UMOUNT_*
constants from <sys/mount.h>."
(let-values (((ret err)
(proc (string->pointer target) flags)))
(unless (zero? ret)
(throw 'system-error "umount" "~S: ~A"
(list target (strerror err))
(list err)))
(when update-mtab?
(remove-from-mtab target))))))
(define (mount-points)
"Return the mounts points for currently mounted file systems."
(call-with-input-file "/proc/mounts"
(lambda (port)
(let loop ((result '()))
(let ((line (read-line port)))
(if (eof-object? line)
(reverse result)
(match (string-tokenize line)
((source mount-point _ ...)
(loop (cons mount-point result))))))))))
(define swapon
(let ((proc (syscall->procedure int "swapon" (list '* int))))
(lambda* (device #:optional (flags 0))
"Use the block special device at DEVICE for swapping."
(let-values (((ret err)
(proc (string->pointer device) flags)))
(unless (zero? ret)
(throw 'system-error "swapon" "~S: ~A"
(list device (strerror err))
(list err)))))))
(define swapoff
(let ((proc (syscall->procedure int "swapoff" '(*))))
(lambda (device)
"Stop using block special device DEVICE for swapping."
(let-values (((ret err) (proc (string->pointer device))))
(unless (zero? ret)
(throw 'system-error "swapoff" "~S: ~A"
(list device (strerror err))
(list err)))))))
(define (kernel? pid)
"Return #t if PID designates a \"kernel thread\" rather than a normal
user-land process."
(let ((stat (call-with-input-file (format #f "/proc/~a/stat" pid)
(compose string-tokenize read-string))))
;; See proc.txt in Linux's documentation for the list of fields.
(match stat
((pid tcomm state ppid pgrp sid tty_nr tty_pgrp flags min_flt
cmin_flt maj_flt cmaj_flt utime stime cutime cstime
priority nice num_thread it_real_value start_time
vsize rss rsslim
(= string->number start_code) (= string->number end_code) _ ...)
;; Got this obscure trick from sysvinit's 'killall5' program.
(and (zero? start_code) (zero? end_code))))))
(define (processes)
"Return the list of live processes."
(sort (filter-map (lambda (file)
(let ((pid (string->number file)))
(and pid
(not (kernel? pid))
pid)))
(scandir "/proc"))
<))
(define mkdtemp!
(let ((proc (syscall->procedure '* "mkdtemp" '(*))))
(lambda (tmpl)
"Create a new unique directory in the file system using the template
string TMPL and return its file name. TMPL must end with 'XXXXXX'."
(let-values (((result err) (proc (string->pointer tmpl))))
(when (null-pointer? result)
(throw 'system-error "mkdtemp!" "~S: ~A"
(list tmpl (strerror err))
(list err)))
(pointer->string result)))))
(define fdatasync
(let ((proc (syscall->procedure int "fdatasync" (list int))))
(lambda (port)
"Flush buffered output of PORT, an output file port, and then call
fdatasync(2) on the underlying file descriptor."
(force-output port)
(let*-values (((fd) (fileno port))
((ret err) (proc fd)))
(unless (zero? ret)
(throw 'system-error "fdatasync" "~S: ~A"
(list fd (strerror err))
(list err)))))))
(define-record-type <file-system>
(file-system type block-size blocks blocks-free
blocks-available files free-files identifier
name-length fragment-size mount-flags spare)
file-system?
(type file-system-type)
(block-size file-system-block-size)
(blocks file-system-block-count)
(blocks-free file-system-blocks-free)
(blocks-available file-system-blocks-available)
(files file-system-file-count)
(free-files file-system-free-file-nodes)
(identifier file-system-identifier)
(name-length file-system-maximum-name-length)
(fragment-size file-system-fragment-size)
(mount-flags file-system-mount-flags)
(spare file-system--spare))
(define-syntax fsword ;fsword_t
(identifier-syntax long))
(define-c-struct %statfs ;<bits/statfs.h>
sizeof-statfs ;slightly overestimated
file-system
read-statfs
write-statfs!
(type fsword)
(block-size fsword)
(blocks uint64)
(blocks-free uint64)
(blocks-available uint64)
(files uint64)
(free-files uint64)
(identifier (array int 2))
(name-length fsword)
(fragment-size fsword)
(mount-flags fsword)
(spare (array fsword 4)))
(define statfs
(let ((proc (syscall->procedure int "statfs64" '(* *))))
(lambda (file)
"Return a <file-system> data structure describing the file system
mounted at FILE."
(let*-values (((stat) (make-bytevector sizeof-statfs))
((ret err) (proc (string->pointer file)
(bytevector->pointer stat))))
(if (zero? ret)
(read-statfs stat)
(throw 'system-error "statfs" "~A: ~A"
(list file (strerror err))
(list err)))))))
;;;
;;; Containers.
;;;
;; Linux clone flags, from linux/sched.h
(define CLONE_CHILD_CLEARTID #x00200000)
(define CLONE_CHILD_SETTID #x01000000)
(define CLONE_NEWNS #x00020000)
(define CLONE_NEWUTS #x04000000)
(define CLONE_NEWIPC #x08000000)
(define CLONE_NEWUSER #x10000000)
(define CLONE_NEWPID #x20000000)
(define CLONE_NEWNET #x40000000)
;; The libc interface to sys_clone is not useful for Scheme programs, so the
;; low-level system call is wrapped instead. The 'syscall' function is
;; declared in <unistd.h> as a variadic function; in practice, it expects 6
;; pointer-sized arguments, as shown in, e.g., x86_64/syscall.S.
(define clone
(let* ((proc (syscall->procedure int "syscall"
(list long ;sysno
unsigned-long ;flags
'* '* '*
'*)))
;; TODO: Don't do this.
(syscall-id (match (utsname:machine (uname))
("i686" 120)
("x86_64" 56)
("mips64" 5055)
("armv7l" 120)
(_ #f))))
(lambda (flags)
"Create a new child process by duplicating the current parent process.
Unlike the fork system call, clone accepts FLAGS that specify which resources
are shared between the parent and child processes."
(let-values (((ret err)
(proc syscall-id flags
%null-pointer ;child stack
%null-pointer %null-pointer ;ptid & ctid
%null-pointer))) ;unused
(if (= ret -1)
(throw 'system-error "clone" "~d: ~A"
(list flags (strerror err))
(list err))
ret)))))
(define setns
;; Some systems may be using an old (pre-2.14) version of glibc where there
;; is no 'setns' function available.
(false-if-exception
(let ((proc (syscall->procedure int "setns" (list int int))))
(lambda (fdes nstype)
"Reassociate the current process with the namespace specified by FDES, a
file descriptor obtained by opening a /proc/PID/ns/* file. NSTYPE specifies
which type of namespace the current process may be reassociated with, or 0 if
there is no such limitation."
(let-values (((ret err) (proc fdes nstype)))
(unless (zero? ret)
(throw 'system-error "setns" "~d ~d: ~A"
(list fdes nstype (strerror err))
(list err))))))))
(define pivot-root
(let ((proc (syscall->procedure int "pivot_root" (list '* '*))))
(lambda (new-root put-old)
"Change the root file system to NEW-ROOT and move the current root file
system to PUT-OLD."
(let-values (((ret err)
(proc (string->pointer new-root)
(string->pointer put-old))))
(unless (zero? ret)
(throw 'system-error "pivot_root" "~S ~S: ~A"
(list new-root put-old (strerror err))
(list err)))))))
;;;
;;; Advisory file locking.
;;;
(define-c-struct %struct-flock ;<fcntl.h>
sizeof-flock
list
read-flock
write-flock!
(type short)
(whence short)
(start size_t)
(length size_t)
(pid int))
(define F_SETLKW
;; On Linux-based systems, this is usually 7, but not always
;; (exceptions include SPARC.) On GNU/Hurd, it's 9.
(cond ((string-contains %host-type "sparc") 9) ; sparc-*-linux-gnu
((string-contains %host-type "linux") 7) ; *-linux-gnu
(else 9))) ; *-gnu*
(define F_SETLK
;; Likewise: GNU/Hurd and SPARC use 8, while the others typically use 6.
(cond ((string-contains %host-type "sparc") 8) ; sparc-*-linux-gnu
((string-contains %host-type "linux") 6) ; *-linux-gnu
(else 8))) ; *-gnu*
(define F_xxLCK
;; The F_RDLCK, F_WRLCK, and F_UNLCK constants.
(cond ((string-contains %host-type "sparc") #(1 2 3)) ; sparc-*-linux-gnu
((string-contains %host-type "hppa") #(1 2 3)) ; hppa-*-linux-gnu
((string-contains %host-type "linux") #(0 1 2)) ; *-linux-gnu
(else #(1 2 3)))) ; *-gnu*
(define fcntl-flock
(let ((proc (syscall->procedure int "fcntl" `(,int ,int *))))
(lambda* (fd-or-port operation #:key (wait? #t))
"Perform locking OPERATION on the file beneath FD-OR-PORT. OPERATION
must be a symbol, one of 'read-lock, 'write-lock, or 'unlock. When WAIT? is
true, block until the lock is acquired; otherwise, thrown an 'flock-error'
exception if it's already taken."
(define (operation->int op)
(case op
((read-lock) (vector-ref F_xxLCK 0))
((write-lock) (vector-ref F_xxLCK 1))
((unlock) (vector-ref F_xxLCK 2))
(else (error "invalid fcntl-flock operation" op))))
(define fd
(if (port? fd-or-port)
(fileno fd-or-port)
fd-or-port))
(define bv
(make-bytevector sizeof-flock))
(write-flock! bv 0
(operation->int operation) SEEK_SET
0 0 ;whole file
0)
;; XXX: 'fcntl' is a vararg function, but here we happily use the
;; standard ABI; crossing fingers.
(let-values (((ret err)
(proc fd
(if wait?
F_SETLKW ;lock & wait
F_SETLK) ;non-blocking attempt
(bytevector->pointer bv))))
(unless (zero? ret)
;; Presumably we got EAGAIN or so.
(throw 'flock-error err))))))
;;;
;;; Network interfaces.
;;;
(define SIOCGIFCONF ;from <bits/ioctls.h>
(if (string-contains %host-type "linux")
#x8912 ;GNU/Linux
#xf00801a4)) ;GNU/Hurd
(define SIOCGIFFLAGS
(if (string-contains %host-type "linux")
#x8913 ;GNU/Linux
#xc4804191)) ;GNU/Hurd
(define SIOCSIFFLAGS
(if (string-contains %host-type "linux")
#x8914 ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCGIFADDR
(if (string-contains %host-type "linux")
#x8915 ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCSIFADDR
(if (string-contains %host-type "linux")
#x8916 ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCGIFNETMASK
(if (string-contains %host-type "linux")
#x891b ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCSIFNETMASK
(if (string-contains %host-type "linux")
#x891c ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCADDRT
(if (string-contains %host-type "linux")
#x890B ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
(define SIOCDELRT
(if (string-contains %host-type "linux")
#x890C ;GNU/Linux
-1)) ;FIXME: GNU/Hurd?
;; Flags and constants from <net/if.h>.
(define IFF_UP #x1) ;Interface is up
(define IFF_BROADCAST #x2) ;Broadcast address valid.
(define IFF_LOOPBACK #x8) ;Is a loopback net.
(define IF_NAMESIZE 16) ;maximum interface name size
(define-c-struct %ifconf-struct
sizeof-ifconf
list
read-ifconf
write-ifconf!
(length int) ;int ifc_len
(request '*)) ;struct ifreq *ifc_ifcu
(define ifreq-struct-size
;; 'struct ifreq' begins with an array of IF_NAMESIZE bytes containing the
;; interface name (nul-terminated), followed by a bunch of stuff. This is
;; its size in bytes.
(if (= 8 (sizeof '*))
40
32))
(define-c-struct sockaddr-in ;<linux/in.h>
sizeof-sockaddrin
(lambda (family port address)
(make-socket-address family address port))
read-sockaddr-in
write-sockaddr-in!
(family unsigned-short)
(port (int16 ~ big))
(address (int32 ~ big)))
(define-c-struct sockaddr-in6 ;<linux/in6.h>
sizeof-sockaddr-in6
(lambda (family port flowinfo address scopeid)
(make-socket-address family address port flowinfo scopeid))
read-sockaddr-in6
write-sockaddr-in6!
(family unsigned-short)
(port (int16 ~ big))
(flowinfo (int32 ~ big))
(address (int128 ~ big))
(scopeid int32))
(define (write-socket-address! sockaddr bv index)
"Write SOCKADDR, a socket address as returned by 'make-socket-address', to
bytevector BV at INDEX."
(let ((family (sockaddr:fam sockaddr)))
(cond ((= family AF_INET)
(write-sockaddr-in! bv index
family
(sockaddr:port sockaddr)
(sockaddr:addr sockaddr)))
((= family AF_INET6)
(write-sockaddr-in6! bv index
family
(sockaddr:port sockaddr)
(sockaddr:flowinfo sockaddr)
(sockaddr:addr sockaddr)
(sockaddr:scopeid sockaddr)))
(else
(error "unsupported socket address" sockaddr)))))
(define PF_PACKET 17) ;<bits/socket.h>
(define AF_PACKET PF_PACKET)
(define* (read-socket-address bv #:optional (index 0))
"Read a socket address from bytevector BV at INDEX."
(let ((family (bytevector-u16-native-ref bv index)))
(cond ((= family AF_INET)
(read-sockaddr-in bv index))
((= family AF_INET6)
(read-sockaddr-in6 bv index))
(else
;; XXX: Unsupported address family, such as AF_PACKET. Return a
;; vector such that the vector can at least call 'sockaddr:fam'.
(vector family)))))
(define %ioctl
;; The most terrible interface, live from Scheme.
(syscall->procedure int "ioctl" (list int unsigned-long '*)))
(define (bytes->string bytes)
"Read BYTES, a list of bytes, and return the null-terminated string decoded
from there, or #f if that would be an empty string."
(match (take-while (negate zero?) bytes)
(()
#f)
(non-zero
(list->string (map integer->char non-zero)))))
(define (bytevector->string-list bv stride len)
"Return the null-terminated strings found in BV every STRIDE bytes. Read at
most LEN bytes from BV."
(let loop ((bytes (take (bytevector->u8-list bv)
(min len (bytevector-length bv))))
(result '()))
(match bytes
(()
(reverse result))
(_
(loop (drop bytes stride)
(cons (bytes->string bytes) result))))))
(define* (network-interface-names #:optional sock)
"Return the names of existing network interfaces. This is typically limited
to interfaces that are currently up."
(let* ((close? (not sock))
(sock (or sock (socket SOCK_STREAM AF_INET 0)))
(len (* ifreq-struct-size 10))
(reqs (make-bytevector len))
(conf (make-bytevector sizeof-ifconf)))
(write-ifconf! conf 0
len (bytevector->pointer reqs))
(let-values (((ret err)
(%ioctl (fileno sock) SIOCGIFCONF
(bytevector->pointer conf))))
(when close?
(close-port sock))
(if (zero? ret)
(bytevector->string-list reqs ifreq-struct-size
(match (read-ifconf conf)
((len . _) len)))
(throw 'system-error "network-interface-list"
"network-interface-list: ~A"
(list (strerror err))
(list err))))))
(define %interface-line
;; Regexp matching an interface line in Linux's /proc/net/dev.
(make-regexp "^[[:blank:]]*([[:graph:]]+):.*$"))
(define (all-network-interface-names)
"Return all the names of the registered network interfaces, including those
that are not up."
(call-with-input-file "/proc/net/dev" ;XXX: Linux-specific
(lambda (port)
(let loop ((interfaces '()))
(let ((line (read-line port)))
(cond ((eof-object? line)
(reverse interfaces))
((regexp-exec %interface-line line)
=>
(lambda (match)
(loop (cons (match:substring match 1) interfaces))))
(else
(loop interfaces))))))))
(define (network-interface-flags socket name)
"Return a number that is the bit-wise or of 'IFF*' flags for network
interface NAME."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
(let-values (((ret err)
(%ioctl (fileno socket) SIOCGIFFLAGS
(bytevector->pointer req))))
(if (zero? ret)
;; The 'ifr_flags' field is IF_NAMESIZE bytes after the beginning of
;; 'struct ifreq', and it's a short int.
(bytevector-sint-ref req IF_NAMESIZE (native-endianness)
(sizeof short))
(throw 'system-error "network-interface-flags"
"network-interface-flags on ~A: ~A"
(list name (strerror err))
(list err))))))
(define (loopback-network-interface? name)
"Return true if NAME designates a loopback network interface."
(let* ((sock (socket SOCK_STREAM AF_INET 0))
(flags (network-interface-flags sock name)))
(close-port sock)
(not (zero? (logand flags IFF_LOOPBACK)))))
(define (set-network-interface-flags socket name flags)
"Set the flag of network interface NAME to FLAGS."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
;; Set the 'ifr_flags' field.
(bytevector-uint-set! req IF_NAMESIZE flags (native-endianness)
(sizeof short))
(let-values (((ret err)
(%ioctl (fileno socket) SIOCSIFFLAGS
(bytevector->pointer req))))
(unless (zero? ret)
(throw 'system-error "set-network-interface-flags"
"set-network-interface-flags on ~A: ~A"
(list name (strerror err))
(list err))))))
(define (set-network-interface-address socket name sockaddr)
"Set the address of network interface NAME to SOCKADDR."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
;; Set the 'ifr_addr' field.
(write-socket-address! sockaddr req IF_NAMESIZE)
(let-values (((ret err)
(%ioctl (fileno socket) SIOCSIFADDR
(bytevector->pointer req))))
(unless (zero? ret)
(throw 'system-error "set-network-interface-address"
"set-network-interface-address on ~A: ~A"
(list name (strerror err))
(list err))))))
(define (set-network-interface-netmask socket name sockaddr)
"Set the network mask of interface NAME to SOCKADDR."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
;; Set the 'ifr_addr' field.
(write-socket-address! sockaddr req IF_NAMESIZE)
(let-values (((ret err)
(%ioctl (fileno socket) SIOCSIFNETMASK
(bytevector->pointer req))))
(unless (zero? ret)
(throw 'system-error "set-network-interface-netmask"
"set-network-interface-netmask on ~A: ~A"
(list name (strerror err))
(list err))))))
(define (network-interface-address socket name)
"Return the address of network interface NAME. The result is an object of
the same type as that returned by 'make-socket-address'."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
(let-values (((ret err)
(%ioctl (fileno socket) SIOCGIFADDR
(bytevector->pointer req))))
(if (zero? ret)
(read-socket-address req IF_NAMESIZE)
(throw 'system-error "network-interface-address"
"network-interface-address on ~A: ~A"
(list name (strerror err))
(list err))))))
(define (network-interface-netmask socket name)
"Return the netmask of network interface NAME. The result is an object of
the same type as that returned by 'make-socket-address'."
(let ((req (make-bytevector ifreq-struct-size)))
(bytevector-copy! (string->utf8 name) 0 req 0
(min (string-length name) (- IF_NAMESIZE 1)))
(let-values (((ret err)
(%ioctl (fileno socket) SIOCGIFNETMASK
(bytevector->pointer req))))
(if (zero? ret)
(read-socket-address req IF_NAMESIZE)
(throw 'system-error "network-interface-netmask"
"network-interface-netmask on ~A: ~A"
(list name (strerror err))
(list err))))))
(define* (configure-network-interface name sockaddr flags
#:key netmask)
"Configure network interface NAME to use SOCKADDR, an address as returned by
'make-socket-address', and FLAGS, a bitwise-or of IFF_* constants. If NETMASK
is true, it must be a socket address to use as the network mask."
(let ((sock (socket (sockaddr:fam sockaddr) SOCK_STREAM 0)))
(dynamic-wind
(const #t)
(lambda ()
(set-network-interface-address sock name sockaddr)
(set-network-interface-flags sock name flags)
(when netmask
(set-network-interface-netmask sock name netmask)))
(lambda ()
(close-port sock)))))
(define* (set-network-interface-up name
#:key (family AF_INET))
"Turn up the interface NAME."
(let ((sock (socket family SOCK_STREAM 0)))
(dynamic-wind
(const #t)
(lambda ()
(let ((flags (network-interface-flags sock name)))
(set-network-interface-flags sock name
(logior flags IFF_UP))))
(lambda ()
(close-port sock)))))
;;;
;;; Network routes.
;;;
(define-c-struct %rtentry ;'struct rtentry' from <net/route.h>
sizeof-rtentry
list
read-rtentry
write-rtentry!
(pad1 unsigned-long)
(destination (array uint8 16)) ;struct sockaddr
(gateway (array uint8 16)) ;struct sockaddr
(genmask (array uint8 16)) ;struct sockaddr
(flags unsigned-short)
(pad2 short)
(pad3 long)
(tos uint8)
(class uint8)
(pad4 (array uint8 (if (= 8 (sizeof* '*)) 3 1)))
(metric short)
(device '*)
(mtu unsigned-long)
(window unsigned-long)
(initial-rtt unsigned-short))
(define RTF_UP #x0001) ;'rtentry' flags from <net/route.h>
(define RTF_GATEWAY #x0002)
(define %sockaddr-any
(make-socket-address AF_INET INADDR_ANY 0))
(define add-network-route/gateway
;; To allow field names to be matched as literals, we need to move them out
;; of the lambda's body since the parameters have the same name. A lot of
;; fuss for very little.
(let-syntax ((gateway-offset (identifier-syntax
(c-struct-field-offset %rtentry gateway)))
(destination-offset (identifier-syntax
(c-struct-field-offset %rtentry destination)))
(genmask-offset (identifier-syntax
(c-struct-field-offset %rtentry genmask))))
(lambda* (socket gateway
#:key (destination %sockaddr-any) (genmask %sockaddr-any))
"Add a network route for DESTINATION (a socket address as returned by
'make-socket-address') that goes through GATEWAY (a socket address). For
instance, the call:
(add-network-route/gateway sock
(make-socket-address
AF_INET
(inet-pton AF_INET \"192.168.0.1\")
0))
is equivalent to this 'net-tools' command:
route add -net default gw 192.168.0.1
because the default value of DESTINATION is \"0.0.0.0\"."
(let ((route (make-bytevector sizeof-rtentry 0)))
(write-socket-address! gateway route gateway-offset)
(write-socket-address! destination route destination-offset)
(write-socket-address! genmask route genmask-offset)
(bytevector-u16-native-set! route
(c-struct-field-offset %rtentry flags)
(logior RTF_UP RTF_GATEWAY))
(let-values (((ret err)
(%ioctl (fileno socket) SIOCADDRT
(bytevector->pointer route))))
(unless (zero? ret)
(throw 'system-error "add-network-route/gateway"
"add-network-route/gateway: ~A"
(list (strerror err))
(list err))))))))
(define delete-network-route
(let-syntax ((destination-offset (identifier-syntax
(c-struct-field-offset %rtentry destination))))
(lambda* (socket destination)
"Delete the network route for DESTINATION. For instance, the call:
(delete-network-route sock
(make-socket-address AF_INET INADDR_ANY 0))
is equivalent to the 'net-tools' command:
route del -net default
"
(let ((route (make-bytevector sizeof-rtentry 0)))
(write-socket-address! destination route destination-offset)
(let-values (((ret err)
(%ioctl (fileno socket) SIOCDELRT
(bytevector->pointer route))))
(unless (zero? ret)
(throw 'system-error "delete-network-route"
"delete-network-route: ~A"
(list (strerror err))
(list err))))))))
;;;
;;; Details about network interfaces---aka. 'getifaddrs'.
;;;
;; Network interfaces. XXX: We would call it <network-interface> but that
;; would collide with the ioctl wrappers above.
(define-record-type <interface>
(make-interface name flags address netmask broadcast-address)
interface?
(name interface-name) ;string
(flags interface-flags) ;or'd IFF_* values
(address interface-address) ;sockaddr | #f
(netmask interface-netmask) ;sockaddr | #f
(broadcast-address interface-broadcast-address)) ;sockaddr | #f
(define (write-interface interface port)
(match interface
(($ <interface> name flags address)
(format port "#<interface ~s " name)
(unless (zero? (logand IFF_UP flags))
(display "up " port))
;; Check whether ADDRESS really is a sockaddr.
(when address
(if (member (sockaddr:fam address) (list AF_INET AF_INET6))
(format port "~a " (inet-ntop (sockaddr:fam address)
(sockaddr:addr address)))
(format port "family:~a " (sockaddr:fam address))))
(format port "~a>" (number->string (object-address interface) 16)))))
(set-record-type-printer! <interface> write-interface)
(define (values->interface next name flags address netmask
broadcast-address data)
"Given the raw field values passed as arguments, return a pair whose car is
an <interface> object, and whose cdr is the pointer NEXT."
(define (maybe-socket-address pointer)
(if (null-pointer? pointer)
#f
(read-socket-address (pointer->bytevector pointer 50)))) ;XXX: size
(cons (make-interface (if (null-pointer? name)
#f
(pointer->string name))
flags
(maybe-socket-address address)
(maybe-socket-address netmask)
(maybe-socket-address broadcast-address)
;; Ignore DATA.
)
next))
(define-c-struct ifaddrs ;<ifaddrs.h>
%sizeof-ifaddrs
values->interface
read-ifaddrs
write-ifaddrs!
(next '*)
(name '*)
(flags unsigned-int)
(addr '*)
(netmask '*)
(broadcastaddr '*)
(data '*))
(define (unfold-interface-list ptr)
"Call 'read-ifaddrs' on PTR and all its 'next' fields, recursively, and
return the list of resulting <interface> objects."
(let loop ((ptr ptr)
(result '()))
(if (null-pointer? ptr)
(reverse result)
(match (read-ifaddrs (pointer->bytevector ptr %sizeof-ifaddrs))
((ifaddr . ptr)
(loop ptr (cons ifaddr result)))))))
(define network-interfaces
(let ((proc (syscall->procedure int "getifaddrs" (list '*))))
(lambda ()
"Return a list of <interface> objects, each denoting a configured
network interface. This is implemented using the 'getifaddrs' libc function."
(let*-values (((ptr)
(bytevector->pointer (make-bytevector (sizeof* '*))))
((ret err)
(proc ptr)))
(if (zero? ret)
(let* ((ptr (dereference-pointer ptr))
(result (unfold-interface-list ptr)))
(free-ifaddrs ptr)
result)
(throw 'system-error "network-interfaces" "~A"
(list (strerror err))
(list err)))))))
(define free-ifaddrs
(syscall->procedure void "freeifaddrs" '(*)))
;;;
;;; Terminals.
;;;
(define-syntax bits->symbols-body
(syntax-rules ()
((_ bits () ())
'())
((_ bits (name names ...) (value values ...))
(let ((result (bits->symbols-body bits (names ...) (values ...))))
(if (zero? (logand bits value))
result
(cons 'name result))))))
(define-syntax define-bits
(syntax-rules (define)
"Define the given numerical constants under CONSTRUCTOR, such that
(CONSTRUCTOR NAME) returns VALUE. Define BITS->SYMBOLS as a procedure that,
given an integer, returns the list of names of the constants that are or'd."
((_ constructor bits->symbols (define names values) ...)
(begin
(define-syntax constructor
(syntax-rules (names ...)
((_ names) values) ...
((_ several (... ...))
(logior (constructor several) (... ...)))))
(define (bits->symbols bits)
(bits->symbols-body bits (names ...) (values ...)))
(define names values) ...))))
;; 'local-flags' bits from <bits/termios.h>
(define-bits local-flags
local-flags->symbols
(define ISIG #o0000001)
(define ICANON #o0000002)
(define XCASE #o0000004)
(define ECHO #o0000010)
(define ECHOE #o0000020)
(define ECHOK #o0000040)
(define ECHONL #o0000100)
(define NOFLSH #o0000200)
(define TOSTOP #o0000400)
(define ECHOCTL #o0001000)
(define ECHOPRT #o0002000)
(define ECHOKE #o0004000)
(define FLUSHO #o0010000)
(define PENDIN #o0040000)
(define IEXTEN #o0100000)
(define EXTPROC #o0200000))
;; "Actions" values for 'tcsetattr'.
(define-bits tcsetattr-action
%unused-tcsetattr-action->symbols
(define TCSANOW 0)
(define TCSADRAIN 1)
(define TCSAFLUSH 2))
(define-record-type <termios>
(termios input-flags output-flags control-flags local-flags
line-discipline control-chars
input-speed output-speed)
termios?
(input-flags termios-input-flags)
(output-flags termios-output-flags)
(control-flags termios-control-flags)
(local-flags termios-local-flags)
(line-discipline termios-line-discipline)
(control-chars termios-control-chars)
(input-speed termios-input-speed)
(output-speed termios-output-speed))
(define-c-struct %termios ;<bits/termios.h>
sizeof-termios
termios
read-termios
write-termios!
(input-flags unsigned-int)
(output-flags unsigned-int)
(control-flags unsigned-int)
(local-flags unsigned-int)
(line-discipline uint8)
(control-chars (array uint8 32))
(input-speed unsigned-int)
(output-speed unsigned-int))
(define tcgetattr
(let ((proc (syscall->procedure int "tcgetattr" (list int '*))))
(lambda (fd)
"Return the <termios> structure for the tty at FD."
(let*-values (((bv) (make-bytevector sizeof-termios))
((ret err) (proc fd (bytevector->pointer bv))))
(if (zero? ret)
(read-termios bv)
(throw 'system-error "tcgetattr" "~A"
(list (strerror err))
(list err)))))))
(define tcsetattr
(let ((proc (syscall->procedure int "tcsetattr" (list int int '*))))
(lambda (fd actions termios)
"Use TERMIOS for the tty at FD. ACTIONS is one of of the values
produced by 'tcsetattr-action'; see tcsetattr(3) for details."
(define bv
(make-bytevector sizeof-termios))
(let-syntax ((match/write (syntax-rules ()
((_ fields ...)
(match termios
(($ <termios> fields ...)
(write-termios! bv 0 fields ...)))))))
(match/write input-flags output-flags control-flags local-flags
line-discipline control-chars input-speed output-speed))
(let-values (((ret err) (proc fd actions (bytevector->pointer bv))))
(unless (zero? ret)
(throw 'system-error "tcgetattr" "~A"
(list (strerror err))
(list err)))))))
(define-syntax TIOCGWINSZ ;<asm-generic/ioctls.h>
(identifier-syntax #x5413))
(define-record-type <window-size>
(window-size rows columns x-pixels y-pixels)
window-size?
(rows window-size-rows)
(columns window-size-columns)
(x-pixels window-size-x-pixels)
(y-pixels window-size-y-pixels))
(define-c-struct winsize ;<bits/ioctl-types.h>
sizeof-winsize
window-size
read-winsize
write-winsize!
(rows unsigned-short)
(columns unsigned-short)
(x-pixels unsigned-short)
(y-pixels unsigned-short))
(define* (terminal-window-size #:optional (port (current-output-port)))
"Return a <window-size> structure describing the terminal at PORT, or raise
a 'system-error' if PORT is not backed by a terminal. This procedure
corresponds to the TIOCGWINSZ ioctl."
(let*-values (((size) (make-bytevector sizeof-winsize))
((ret err) (%ioctl (fileno port) TIOCGWINSZ
(bytevector->pointer size))))
(if (zero? ret)
(read-winsize size)
(throw 'system-error "terminal-window-size" "~A"
(list (strerror err))
(list err)))))
(define* (terminal-columns #:optional (port (current-output-port)))
"Return the best approximation of the number of columns of the terminal at
PORT, trying to guess a reasonable value if all else fails. The result is
always a positive integer."
(define (fall-back)
(match (and=> (getenv "COLUMNS") string->number)
(#f 80)
((? number? columns)
(if (> columns 0) columns 80))))
(catch 'system-error
(lambda ()
(if (file-port? port)
(match (window-size-columns (terminal-window-size port))
;; Things like Emacs shell-mode return 0, which is unreasonable.
(0 (fall-back))
((? number? columns) columns))
(fall-back)))
(lambda args
(let ((errno (system-error-errno args)))
;; ENOTTY is what we're after but 2012-and-earlier Linux versions
;; would return EINVAL instead in some cases:
;; <https://bugs.ruby-lang.org/issues/10494>.
;; Furthermore, some FUSE file systems like unionfs return ENOSYS for
;; that ioctl.
(if (memv errno (list ENOTTY EINVAL ENOSYS))
(fall-back)
(apply throw args))))))
;;; syscalls.scm ends here