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authorLudovic Courtès <ludo@gnu.org>2016-05-30 22:44:58 +0200
committerLudovic Courtès <ludo@gnu.org>2016-05-31 00:11:04 +0200
commitc06f6db7a424fd47e3cd2625dbfda2367316f3bd (patch)
tree025d18dd2ed6d4f6a62cc09aa9633161c7d7edc8 /gnu/build
parent4c14d4eaa7ee9d5d89c04a41adb50c7c532d14e1 (diff)
container: Gracefully report mount errors in the child process.
Fixes <http://bugs.gnu.org/23306>. * gnu/build/linux-container.scm (run-container): Use 'socketpair' instead of 'pipe'. Rename 'in' to 'child' and 'out' to 'parent'. Send a 'ready message or an exception argument list from the child to the parent; adjust the parent accordingly. * tests/containers.scm ("call-with-container, mnt namespace, wrong bind mount"): New test. * tests/guix-environment-container.sh: Add test with --expose=/does-not-exist.
Diffstat (limited to 'gnu/build')
-rw-r--r--gnu/build/linux-container.scm42
1 files changed, 30 insertions, 12 deletions
diff --git a/gnu/build/linux-container.scm b/gnu/build/linux-container.scm
index 562d50bcc7..91996d06ca 100644
--- a/gnu/build/linux-container.scm
+++ b/gnu/build/linux-container.scm
@@ -205,35 +205,53 @@ host user identifiers to map into the user namespace."
;; The parent process must initialize the user namespace for the child
;; before it can boot. To negotiate this, a pipe is used such that the
;; child process blocks until the parent writes to it.
- (match (pipe)
- ((in . out)
+ (match (socketpair PF_UNIX SOCK_STREAM 0)
+ ((child . parent)
(let ((flags (namespaces->bit-mask namespaces)))
(match (clone flags)
(0
(call-with-clean-exit
(lambda ()
- (close out)
+ (close-port parent)
;; Wait for parent to set things up.
- (match (read in)
+ (match (read child)
('ready
- (close in)
(purify-environment)
(when (memq 'mnt namespaces)
- (mount-file-systems root mounts
- #:mount-/proc? (memq 'pid namespaces)
- #:mount-/sys? (memq 'net namespaces)))
+ (catch #t
+ (lambda ()
+ (mount-file-systems root mounts
+ #:mount-/proc? (memq 'pid namespaces)
+ #:mount-/sys? (memq 'net
+ namespaces)))
+ (lambda args
+ ;; Forward the exception to the parent process.
+ (write args child)
+ (primitive-exit 3))))
;; TODO: Manage capabilities.
+ (write 'ready child)
+ (close-port child)
(thunk))
(_ ;parent died or something
(primitive-exit 2))))))
(pid
+ (close-port child)
(when (memq 'user namespaces)
(initialize-user-namespace pid host-uids))
;; TODO: Initialize cgroups.
- (close in)
- (write 'ready out)
- (close out)
- pid))))))
+ (write 'ready parent)
+ (newline parent)
+
+ ;; Check whether the child process' setup phase succeeded.
+ (let ((message (read parent)))
+ (close-port parent)
+ (match message
+ ('ready ;success
+ pid)
+ (((? symbol? key) args ...) ;exception
+ (apply throw key args))
+ (_ ;unexpected termination
+ #f)))))))))
(define* (call-with-container mounts thunk #:key (namespaces %namespaces)
(host-uids 1))