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guix-play/guix/build/syscalls.scm
Jan (janneke) Nieuwenhuizen ab9e30039d
syscalls: set-thread-name, thread-name: Fix thinko. 
* guix/build/syscalls.scm (set-thread-name, thread-name): Oops, fix thinko.
2020-06-08 16:49:03 +02:00

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
;;; Copyright © 2020 Julien Lepiller <julien@lepiller.eu>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.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 (system base target)
#:use-module (rnrs bytevectors)
#:autoload (ice-9 binary-ports) (get-bytevector-n)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-19)
#:use-module (srfi srfi-26)
#: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_NOATIME
MS_BIND
MS_MOVE
MS_STRICTATIME
MS_LAZYTIME
MNT_FORCE
MNT_DETACH
MNT_EXPIRE
UMOUNT_NOFOLLOW
restart-on-EINTR
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
free-disk-space
device-in-use?
add-to-entropy-count
processes
mkdtemp!
fdatasync
pivot-root
scandir*
getxattr
setxattr
fcntl-flock
lock-file
unlock-file
with-file-lock
with-file-lock/no-wait
set-thread-name
thread-name
CLONE_CHILD_CLEARTID
CLONE_CHILD_SETTID
CLONE_NEWNS
CLONE_NEWUTS
CLONE_NEWIPC
CLONE_NEWUSER
CLONE_NEWPID
CLONE_NEWNET
clone
setns
PF_PACKET
AF_PACKET
all-network-interface-names
network-interface-names
network-interface-netmask
network-interface-running?
loopback-network-interface?
arp-network-interface?
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
input-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
terminal-rows
utmpx?
utmpx-login-type
utmpx-pid
utmpx-line
utmpx-id
utmpx-user
utmpx-host
utmpx-termination-status
utmpx-exit-status
utmpx-session-id
utmpx-time
utmpx-address
login-type
utmpx-entries
(read-utmpx-from-port . read-utmpx)))
;;; Commentary:
;;;
;;; This module provides bindings to libc's syscall wrappers. It uses the
;;; FFI, and thus requires a dynamically-linked Guile.
;;;
;;; Some syscalls are already defined in statically-linked Guile by applying
;;; 'guile-linux-syscalls.patch'.
;;;
;;; Visibility of syscall's symbols shared between this module and static Guile
;;; is a bit delicate. It is handled by 'define-as-needed' macro.
;;;
;;; This macro is used to export symbols in dynamic Guile context, and to
;;; re-export them in static Guile context.
;;;
;;; This way, even if they don't appear in #:export list, it is safe to use
;;; syscalls from this module in static or dynamic Guile context.
;;;
;;; 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)
;; When compiling natively, call 'sizeof' at expansion
;; time; otherwise, emit code to call it at run time.
(syntax-case s ()
(_
(if (= (target-word-size)
(with-target %host-type target-word-size))
(sizeof type)
#'(sizeof type)))))))
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)
;; When compiling natively, call 'sizeof' at expansion
;; time; otherwise, emit code to call it at run time.
(syntax-case s ()
(_
(if (= (target-word-size)
(with-target %host-type target-word-size))
(alignof type)
#'(alignof type)))))))
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 (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.
(pointer->procedure return-type ptr argument-types
#:return-errno? #t)))
(lambda args
(lambda _
(throw 'system-error name "~A" (list (strerror ENOSYS))
(list ENOSYS))))))
(define-syntax define-as-needed
(syntax-rules ()
"Define VARIABLE. If VARIABLE already exists in (guile) then re-export it,
otherwise export the newly-defined VARIABLE."
((_ (proc args ...) body ...)
(define-as-needed proc (lambda* (args ...) body ...)))
((_ variable value)
(if (module-defined? the-scm-module 'variable)
(module-re-export! (current-module) '(variable))
(begin
(module-define! (current-module) 'variable value)
(module-export! (current-module) '(variable)))))))
;;;
;;; 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_NOATIME 1024)
(define MS_BIND 4096)
(define MS_MOVE 8192)
(define MS_STRICTATIME 16777216)
(define MS_LAZYTIME 33554432)
(define MNT_FORCE 1)
(define MNT_DETACH 2)
(define MNT_EXPIRE 4)
(define UMOUNT_NOFOLLOW 8)
(define-as-needed (mount 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."
;; XXX: '#:update-mtab?' is not implemented by core 'mount'.
(let ((proc (syscall->procedure int "mount" `(* * * ,unsigned-long *))))
(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-as-needed (umount 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>."
;; XXX: '#:update-mtab?' is not implemented by core 'umount'.
(let ((proc (syscall->procedure int "umount2" `(* ,int))))
(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-as-needed RB_AUTOBOOT #x01234567)
(define-as-needed RB_HALT_SYSTEM #xcdef0123)
(define-as-needed RB_ENABLED_CAD #x89abcdef)
(define-as-needed RB_DISABLE_CAD 0)
(define-as-needed RB_POWER_OFF #x4321fedc)
(define-as-needed RB_SW_SUSPEND #xd000fce2)
(define-as-needed RB_KEXEC #x45584543)
(define-as-needed (reboot #:optional (cmd RB_AUTOBOOT))
(let ((proc (syscall->procedure int "reboot" (list int))))
(let-values (((ret err) (proc cmd)))
(unless (zero? ret)
(throw 'system-error "reboot" "~S: ~A"
(list cmd (strerror err))
(list err))))))
(define-as-needed (load-linux-module data #:optional (options ""))
(let ((proc (syscall->procedure int "init_module"
(list '* unsigned-long '*))))
(let-values (((ret err)
(proc (bytevector->pointer data)
(bytevector-length data)
(string->pointer options))))
(unless (zero? ret)
(throw 'system-error "load-linux-module" "~A"
(list (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)))))))
(define (free-disk-space file)
"Return the free disk space, in bytes, on the file system that hosts FILE."
(let ((fs (statfs file)))
(* (file-system-block-size fs)
(file-system-blocks-available fs))))
;; Flags for the *at command, notably the 'utime' procedure of libguile.
;; From <fcntl.h>.
(define-as-needed AT_FDCWD -100)
(define-as-needed AT_SYMLINK_NOFOLLOW #x100)
(define-as-needed AT_REMOVEDIR #x200)
(define-as-needed AT_SYMLINK_FOLLOW #x400)
(define-as-needed AT_NO_AUTOMOUNT #x800)
(define-as-needed AT_EMPTY_PATH #x1000)
(define-syntax BLKRRPART ;<sys/mount.h>
(identifier-syntax #x125F))
(define* (device-in-use? device)
"Return #t if the block DEVICE is in use, #f otherwise. This is inspired
from fdisk_device_is_used function of util-linux. This is particularly useful
for devices that do not appear in /proc/self/mounts like overlayfs lowerdir
backend device."
(let*-values (((fd) (open-fdes device O_RDONLY))
((ret err) (%ioctl fd BLKRRPART %null-pointer)))
(close-fdes fd)
(cond
((= ret 0)
#f)
((= err EBUSY)
#t)
((= err EINVAL)
;; We get EINVAL for devices that have the GENHD_FL_NO_PART_SCAN flag
;; set in the kernel, in particular loopback devices, though we do seem
;; to get it for SCSI storage (/dev/sr0) on QEMU.
#f)
(else
(throw 'system-error "ioctl" "~A"
(list (strerror err))
(list err))))))
(define getxattr
(let ((proc (syscall->procedure ssize_t "getxattr"
`(* * * ,size_t))))
(lambda (file key)
"Get the extended attribute value for KEY on FILE."
(let-values (((size err)
;; Get size of VALUE for buffer.
(proc (string->pointer/utf-8 file)
(string->pointer key)
(string->pointer "")
0)))
(cond ((< size 0) #f)
((zero? size) "")
;; Get VALUE in buffer of SIZE. XXX actual size can race.
(else (let*-values (((buf) (make-bytevector size))
((size err)
(proc (string->pointer/utf-8 file)
(string->pointer key)
(bytevector->pointer buf)
size)))
(if (>= size 0)
(utf8->string buf)
(throw 'system-error "getxattr" "~S: ~A"
(list file key (strerror err))
(list err))))))))))
(define setxattr
(let ((proc (syscall->procedure int "setxattr"
`(* * * ,size_t ,int))))
(lambda* (file key value #:optional (flags 0))
"Set extended attribute KEY to VALUE on FILE."
(let*-values (((bv) (string->utf8 value))
((ret err)
(proc (string->pointer/utf-8 file)
(string->pointer key)
(bytevector->pointer bv)
(bytevector-length bv)
flags)))
(unless (zero? ret)
(throw 'system-error "setxattr" "~S: ~A"
(list file key value (strerror err))
(list err)))))))
;;;
;;; Random.
;;;
;; From <uapi/linux/random.h>.
(define RNDADDTOENTCNT #x40045201)
(define (add-to-entropy-count port-or-fd n)
"Add N to the kernel's entropy count (the value that can be read from
/proc/sys/kernel/random/entropy_avail). PORT-OR-FD must correspond to
/dev/urandom or /dev/random. Raise to 'system-error with EPERM when the
caller lacks root privileges."
(let ((fd (if (port? port-or-fd)
(fileno port-or-fd)
port-or-fd))
(box (make-bytevector (sizeof int))))
(bytevector-sint-set! box 0 n (native-endianness)
(sizeof int))
(let-values (((ret err)
(%ioctl fd RNDADDTOENTCNT
(bytevector->pointer box))))
(unless (zero? err)
(throw 'system-error "add-to-entropy-count" "~A"
(list (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)
(define %set-automatic-finalization-enabled?!
;; When using a statically-linked Guile, for instance in the initrd, we
;; cannot resolve this symbol, but most of the time we don't need it
;; anyway. Thus, delay it.
(let ((proc (delay
(pointer->procedure int
(dynamic-func
"scm_set_automatic_finalization_enabled"
(dynamic-link))
(list int)))))
(lambda (enabled?)
"Switch on or off automatic finalization in a separate thread.
Turning finalization off shuts down the finalization thread as a side effect."
(->bool ((force proc) (if enabled? 1 0))))))
(define-syntax-rule (without-automatic-finalization exp)
"Turn off automatic finalization within the dynamic extent of EXP."
(let ((enabled? #t))
(dynamic-wind
(lambda ()
(set! enabled? (%set-automatic-finalization-enabled?! #f)))
(lambda ()
exp)
(lambda ()
(%set-automatic-finalization-enabled?! enabled?)))))
;; 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)
("aarch64" 220)
(_ #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)
;; Guile 2.2 runs a finalization thread. 'primitive-fork'
;; takes care of shutting it down before forking, and we
;; must do the same here. Failing to do that, if the
;; child process calls 'primitive-fork', it will hang
;; while trying to pthread_join the finalization thread
;; since that thread does not exist.
(without-automatic-finalization
(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)))))))
;;;
;;; Opendir & co.
;;;
(define (file-type->symbol type)
;; Convert TYPE to symbols like 'stat:type' does.
(cond ((= type DT_REG) 'regular)
((= type DT_LNK) 'symlink)
((= type DT_DIR) 'directory)
((= type DT_FIFO) 'fifo)
((= type DT_CHR) 'char-special)
((= type DT_BLK) 'block-special)
((= type DT_SOCK) 'socket)
(else 'unknown)))
;; 'struct dirent64' for GNU/Linux.
(define-c-struct %struct-dirent-header/linux
sizeof-dirent-header/linux
(lambda (inode offset length type name)
`((type . ,(file-type->symbol type))
(inode . ,inode)))
read-dirent-header/linux
write-dirent-header!/linux
(inode int64)
(offset int64)
(length unsigned-short)
(type uint8)
(name uint8)) ;first byte of 'd_name'
;; 'struct dirent64' for GNU/Hurd.
(define-c-struct %struct-dirent-header/hurd
sizeof-dirent-header/hurd
(lambda (inode length type name-length name)
`((type . ,(file-type->symbol type))
(inode . ,inode)))
read-dirent-header/hurd
write-dirent-header!/hurd
(inode int64)
(length unsigned-short)
(type uint8)
(namelen uint8)
(name uint8))
;; Constants for the 'type' field, from <dirent.h>.
(define DT_UNKNOWN 0)
(define DT_FIFO 1)
(define DT_CHR 2)
(define DT_DIR 4)
(define DT_BLK 6)
(define DT_REG 8)
(define DT_LNK 10)
(define DT_SOCK 12)
(define DT_WHT 14)
(define string->pointer/utf-8
(cut string->pointer <> "UTF-8"))
(define pointer->string/utf-8
(cut pointer->string <> <> "UTF-8"))
(define opendir*
(let ((proc (syscall->procedure '* "opendir" '(*))))
(lambda* (name #:optional (string->pointer string->pointer/utf-8))
(let-values (((ptr err)
(proc (string->pointer name))))
(if (null-pointer? ptr)
(throw 'system-error "opendir*"
"~A: ~A" (list name (strerror err))
(list err))
ptr)))))
(define closedir*
(let ((proc (syscall->procedure int "closedir" '(*))))
(lambda (directory)
(let-values (((ret err)
(proc directory)))
(unless (zero? ret)
(throw 'system-error "closedir"
"closedir: ~A" (list (strerror err))
(list err)))))))
(define (readdir-procedure name-field-offset sizeof-dirent-header
read-dirent-header)
(let ((proc (syscall->procedure '* "readdir64" '(*))))
(lambda* (directory #:optional (pointer->string pointer->string/utf-8))
(let ((ptr (proc directory)))
(and (not (null-pointer? ptr))
(cons (pointer->string
(make-pointer (+ (pointer-address ptr) name-field-offset))
-1)
(read-dirent-header
(pointer->bytevector ptr sizeof-dirent-header))))))))
(define readdir*
;; Decide at run time which one must be used.
(if (string-contains %host-type "linux-gnu")
(readdir-procedure (c-struct-field-offset %struct-dirent-header/linux
name)
sizeof-dirent-header/linux
read-dirent-header/linux)
(readdir-procedure (c-struct-field-offset %struct-dirent-header/hurd
name)
sizeof-dirent-header/hurd
read-dirent-header/hurd)))
(define* (scandir* name #:optional
(select? (const #t))
(entry<? (lambda (entry1 entry2)
(match entry1
((name1 . _)
(match entry2
((name2 . _)
(string<? name1 name2)))))))
#:key
(string->pointer string->pointer/utf-8)
(pointer->string pointer->string/utf-8))
"This procedure improves on Guile's 'scandir' procedure in several ways:
1. Systematically encode decode file names using STRING->POINTER and
POINTER->STRING (UTF-8 by default; this works around a defect in Guile 2.0/2.2
where 'scandir' decodes file names according to the current locale, which is
not always desirable.
2. Each entry that is returned has the form (NAME . PROPERTIES).
PROPERTIES is an alist showing additional properties about the entry, as
found in 'struct dirent'. An entry may look like this:
(\"foo.scm\" (type . regular) (inode . 123456))
Callers must be prepared to deal with the case where 'type' is 'unknown'
since some file systems do not provide that information.
3. Raise to 'system-error' when NAME cannot be opened."
(let ((directory (opendir* name string->pointer)))
(dynamic-wind
(const #t)
(lambda ()
(let loop ((result '()))
(match (readdir* directory pointer->string)
(#f
(sort result entry<?))
(entry
(loop (if (select? entry)
(cons entry result)
result))))))
(lambda ()
(closedir* directory)))))
;;;
;;; 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))))))
(define* (lock-file file #:key (wait? #t))
"Wait and acquire an exclusive lock on FILE. Return an open port."
(let ((port (open-file file "w0")))
(fcntl-flock port 'write-lock #:wait? wait?)
port))
(define (unlock-file port)
"Unlock PORT, a port returned by 'lock-file'."
(fcntl-flock port 'unlock)
(close-port port)
#t)
(define (call-with-file-lock file thunk)
(let ((port #f))
(dynamic-wind
(lambda ()
(set! port
(catch 'system-error
(lambda ()
(lock-file file))
(lambda args
;; When using the statically-linked Guile in the initrd,
;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
;; that error since we're typically the only process running
;; at this point.
(if (= ENOSYS (system-error-errno args))
#f
(apply throw args))))))
thunk
(lambda ()
(when port
(unlock-file port))))))
(define (call-with-file-lock/no-wait file thunk handler)
(let ((port #f))
(dynamic-wind
(lambda ()
(set! port
(catch #t
(lambda ()
(lock-file file #:wait? #f))
(lambda (key . args)
(match key
('flock-error
(apply handler args)
;; No open port to the lock, so return #f.
#f)
('system-error
;; When using the statically-linked Guile in the initrd,
;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
;; that error since we're typically the only process running
;; at this point.
(if (= ENOSYS (system-error-errno (cons key args)))
#f
(apply throw key args)))
(_ (apply throw key args)))))))
thunk
(lambda ()
(when port
(unlock-file port))))))
(define-syntax-rule (with-file-lock file exp ...)
"Wait to acquire a lock on FILE and evaluate EXP in that context."
(call-with-file-lock file (lambda () exp ...)))
(define-syntax-rule (with-file-lock/no-wait file handler exp ...)
"Try to acquire a lock on FILE and evaluate EXP in that context. Execute
handler if the lock is already held by another process."
(call-with-file-lock/no-wait file (lambda () exp ...) handler))
;;;
;;; Miscellaneous, aka. 'prctl'.
;;;
(define %prctl
;; Should it win the API contest against 'ioctl'? You tell us!
(syscall->procedure int "prctl"
(list int unsigned-long unsigned-long
unsigned-long unsigned-long)))
(define PR_SET_NAME 15) ;<linux/prctl.h>
(define PR_GET_NAME 16)
(define %max-thread-name-length
;; Maximum length in bytes of the process name, including the terminating
;; zero.
16)
(define (set-thread-name!/linux name)
"Set the name of the calling thread to NAME. NAME is truncated to 15
bytes."
(let ((ptr (string->pointer name)))
(let-values (((ret err)
(%prctl PR_SET_NAME
(pointer-address ptr) 0 0 0)))
(unless (zero? ret)
(throw 'set-process-name "set-process-name"
"set-process-name: ~A"
(list (strerror err))
(list err))))))
(define (thread-name/linux)
"Return the name of the calling thread as a string."
(let ((buf (make-bytevector %max-thread-name-length)))
(let-values (((ret err)
(%prctl PR_GET_NAME
(pointer-address (bytevector->pointer buf))
0 0 0)))
(if (zero? ret)
(bytes->string (bytevector->u8-list buf))
(throw 'process-name "process-name"
"process-name: ~A"
(list (strerror err))
(list err))))))
(define set-thread-name
(if (string-contains %host-type "linux")
set-thread-name!/linux
(const #f)))
(define thread-name
(if (string-contains %host-type "linux")
thread-name/linux
(const "")))
;;;
;;; Network interfaces.
;;;
(define SIOCGIFCONF ;from <bits/ioctls.h>
; <net/if.h>
; <hurd/ioctl.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
#x84804190)) ;GNU/Hurd
(define SIOCGIFADDR
(if (string-contains %host-type "linux")
#x8915 ;GNU/Linux
#xc08401a1)) ;GNU/Hurd
(define SIOCSIFADDR
(if (string-contains %host-type "linux")
#x8916 ;GNU/Linux
#x8084018c)) ;GNU/Hurd
(define SIOCGIFNETMASK
(if (string-contains %host-type "linux")
#x891b ;GNU/Linux
#xc08401a5)) ;GNU/Hurd
(define SIOCSIFNETMASK
(if (string-contains %host-type "linux")
#x891c ;GNU/Linux
#x80840196)) ;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-as-needed IFF_UP #x1) ;Interface is up
(define-as-needed IFF_BROADCAST #x2) ;Broadcast address valid.
(define-as-needed IFF_LOOPBACK #x8) ;Is a loopback net.
(define-as-needed IFF_RUNNING #x40) ;interface RFC2863 OPER_UP
(define-as-needed IFF_NOARP #x80) ;ARP disabled or unsupported
(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 ;<linux/in.h>
sizeof-sockaddr-in/linux
(lambda (family port address)
(make-socket-address family address port))
read-sockaddr-in/linux
write-sockaddr-in!/linux
(family unsigned-short)
(port (int16 ~ big))
(address (int32 ~ big)))
(define-c-struct sockaddr-in/hurd ;<netinet/in.h>
sizeof-sockaddr-in/hurd
(lambda (len family port address zero)
(make-socket-address family address port))
read-sockaddr-in/hurd
write-sockaddr-in!/hurd
(len uint8)
(family uint8)
(port (int16 ~ big))
(address (int32 ~ big))
(zero (array uint8 8)))
(define-c-struct sockaddr-in6/linux ;<linux/in6.h>
sizeof-sockaddr-in6/linux
(lambda (family port flowinfo address scopeid)
(make-socket-address family address port flowinfo scopeid))
read-sockaddr-in6/linux
write-sockaddr-in6!/linux
(family unsigned-short)
(port (int16 ~ big))
(flowinfo (int32 ~ big))
(address (int128 ~ big))
(scopeid int32))
(define-c-struct sockaddr-in6/hurd ;<netinet/in.h>
sizeof-sockaddr-in6/hurd
(lambda (len family port flowinfo address scopeid)
(make-socket-address family address port flowinfo scopeid))
read-sockaddr-in6/hurd
write-sockaddr-in6!/hurd
(len uint8)
(family uint8)
(port (int16 ~ big))
(flowinfo (int32 ~ big))
(address (int128 ~ big))
(scopeid int32))
(define (write-socket-address!/linux 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!/linux bv index
family
(sockaddr:port sockaddr)
(sockaddr:addr sockaddr)))
((= family AF_INET6)
(write-sockaddr-in6!/linux bv index
family
(sockaddr:port sockaddr)
(sockaddr:flowinfo sockaddr)
(sockaddr:addr sockaddr)
(sockaddr:scopeid sockaddr)))
(else
(error "unsupported socket address" sockaddr)))))
(define (write-socket-address!/hurd 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!/hurd bv index
sizeof-sockaddr-in/hurd
family
(sockaddr:port sockaddr)
(sockaddr:addr sockaddr)
'(0 0 0 0 0 0 0 0)))
((= family AF_INET6)
(write-sockaddr-in6!/hurd bv index
sizeof-sockaddr-in6/hurd
family
(sockaddr:port sockaddr)
(sockaddr:flowinfo sockaddr)
(sockaddr:addr sockaddr)
(sockaddr:scopeid sockaddr)))
(else
(error "unsupported socket address" sockaddr)))))
(define write-socket-address!
(if (string-contains %host-type "linux-gnu")
write-socket-address!/linux
write-socket-address!/hurd))
(define PF_PACKET 17) ;<bits/socket.h>
(define AF_PACKET PF_PACKET)
(define* (read-socket-address/linux 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/linux bv index))
((= family AF_INET6)
(read-sockaddr-in6/linux 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* (read-socket-address/hurd 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/hurd bv index))
((= family AF_INET6)
(read-sockaddr-in6/hurd 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 read-socket-address
(if (string-contains %host-type "linux-gnu")
read-socket-address/linux
read-socket-address/hurd))
(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-as-needed (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 (network-interface-running? name)
"Return true if NAME designates a running network interface."
(let* ((sock (socket SOCK_STREAM AF_INET 0))
(flags (network-interface-flags sock name)))
(close-port sock)
(not (zero? (logand flags IFF_RUNNING)))))
(define (arp-network-interface? name)
"Return true if NAME supports the Address Resolution Protocol."
(let* ((sock (socket SOCK_STREAM AF_INET 0))
(flags (network-interface-flags sock name)))
(close-port sock)
(zero? (logand flags IFF_NOARP))))
(define-as-needed (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-as-needed (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 ...)
((_) 0)
((_ names) values) ...
((_ first rest (... ...))
(logior (constructor first) rest (... ...)))))
(define (bits->symbols bits)
(bits->symbols-body bits (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))
(define-bits input-flags
input-flags->symbols
(define IGNBRK #o0000001)
(define BRKINT #o0000002)
(define IGNPAR #o0000004)
(define PARMRK #o0000010)
(define INPCK #o0000020)
(define ISTRIP #o0000040)
(define INLCR #o0000100)
(define IGNCR #o0000200)
(define ICRNL #o0000400)
(define IUCLC #o0001000)
(define IXON #o0002000)
(define IXANY #o0004000)
(define IXOFF #o0010000)
(define IMAXBEL #o0020000)
(define IUTF8 #o0040000))
;; "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-dimension window-dimension port fall-back)
"Return the terminal dimension defined by WINDOW-DIMENSION, one of
'window-size-columns' or 'window-size-rows' for PORT. If PORT does not
correspond to a terminal, return the value returned by FALL-BACK."
(catch 'system-error
(lambda ()
(if (file-port? port)
(match (window-dimension (terminal-window-size port))
;; Things like Emacs shell-mode return 0, which is unreasonable.
(0 (fall-back))
((? number? n) n))
(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, and bcachefs returns EPERM.
(if (memv errno (list ENOTTY EINVAL ENOSYS EPERM))
(fall-back)
(apply throw args))))))
(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))))
(terminal-dimension window-size-columns port fall-back))
(define* (terminal-rows #:optional (port (current-output-port)))
"Return the best approximation of the number of rows of the terminal at
PORT, trying to guess a reasonable value if all else fails. The result is
always a positive integer."
(terminal-dimension window-size-rows port (const 25)))
;;;
;;; utmpx.
;;;
(define-record-type <utmpx-entry>
(utmpx type pid line id user host termination exit
session time address)
utmpx?
(type utmpx-login-type) ;login-type
(pid utmpx-pid)
(line utmpx-line) ;device name
(id utmpx-id)
(user utmpx-user) ;user name
(host utmpx-host) ;host name | #f
(termination utmpx-termination-status)
(exit utmpx-exit-status)
(session utmpx-session-id) ;session ID, for windowing
(time utmpx-time) ;entry time
(address utmpx-address))
(define-c-struct %utmpx ;<utmpx.h>
sizeof-utmpx
(lambda (type pid line id user host termination exit session
seconds useconds address %reserved)
(utmpx type pid
(bytes->string line) id
(bytes->string user)
(bytes->string host) termination exit
session
(make-time time-utc (* 1000 useconds) seconds)
address))
read-utmpx
write-utmpx!
(type short)
(pid int)
(line (array uint8 32))
(id (array uint8 4))
(user (array uint8 32))
(host (array uint8 256))
(termination short)
(exit short)
(session int32)
(time-seconds int32)
(time-useconds int32)
(address-v6 (array int32 4))
(%reserved (array uint8 20)))
(define-bits login-type
%unused-login-type->symbols
(define EMPTY 0) ;No valid user accounting information.
(define RUN_LVL 1) ;The system's runlevel.
(define BOOT_TIME 2) ;Time of system boot.
(define NEW_TIME 3) ;Time after system clock changed.
(define OLD_TIME 4) ;Time when system clock changed.
(define INIT_PROCESS 5) ;Process spawned by the init process.
(define LOGIN_PROCESS 6) ;Session leader of a logged in user.
(define USER_PROCESS 7) ;Normal process.
(define DEAD_PROCESS 8) ;Terminated process.
(define ACCOUNTING 9)) ;System accounting.
(define setutxent
(let ((proc (syscall->procedure void "setutxent" '())))
(lambda ()
"Open the user accounting database."
(proc))))
(define endutxent
(let ((proc (syscall->procedure void "endutxent" '())))
(lambda ()
"Close the user accounting database."
(proc))))
(define getutxent
(let ((proc (syscall->procedure '* "getutxent" '())))
(lambda ()
"Return the next entry from the user accounting database."
(let ((ptr (proc)))
(if (null-pointer? ptr)
#f
(read-utmpx (pointer->bytevector ptr sizeof-utmpx)))))))
(define (utmpx-entries)
"Return the list of entries read from the user accounting database."
(setutxent)
(let loop ((entries '()))
(match (getutxent)
(#f
(endutxent)
(reverse entries))
((? utmpx? entry)
(loop (cons entry entries))))))
(define (read-utmpx-from-port port)
"Read a utmpx entry from PORT. Return either the EOF object or a utmpx
entry."
(match (get-bytevector-n port sizeof-utmpx)
((? eof-object? eof)
eof)
((? bytevector? bv)
(read-utmpx bv))))
;;; syscalls.scm ends here
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