diff options
Diffstat (limited to 'guix/build/syscalls.scm')
| -rw-r--r-- | guix/build/syscalls.scm | 85 |
1 files changed, 52 insertions, 33 deletions
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm index 56a689f667..66d63a2931 100644 --- a/guix/build/syscalls.scm +++ b/guix/build/syscalls.scm @@ -1,5 +1,5 @@ ;;; GNU Guix --- Functional package management for GNU -;;; Copyright © 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 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> @@ -73,6 +73,7 @@ file-system-mount-flags statfs free-disk-space + device-in-use? processes mkdtemp! @@ -684,6 +685,32 @@ mounted at FILE." (define AT_NO_AUTOMOUNT #x800) (define 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 particulary 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)))))) + ;;; ;;; Containers. @@ -699,39 +726,31 @@ mounted at FILE." (define CLONE_NEWPID #x20000000) (define CLONE_NEWNET #x40000000) -(cond-expand - (guile-2.2 - (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. +(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?)))))) - - (else - (define-syntax-rule (without-automatic-finalization exp) - ;; Nothing to do here: Guile 2.0 does not have a separate finalization - ;; thread. - exp))) + (->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 |