davexunit pushed a commit to branch wip-container
in repository guix.
commit 61ebbe55f7f6d4d4eb42db957d6fc7b4eaf282a6
Author: David Thompson <[email protected]>
Date: Sat Sep 5 14:10:08 2015 -0400
build: container: Use the same clone flags as fork(3).
The intent is to make 'clone' behave a lot more like 'primitive-fork', which
calls clone(2) with SIGCHLD, CLONE_CHILD_CLEARTID, and CLONE_CHILD_SETTID
flags. Notably, running 'clone' at the REPL without these flags would break
the REPL beyond repair.
* guix/build/syscalls.scm (CLONE_CHILD_CLEARTID, CLONE_CHILD_SETTID): New
variables.
* gnu/build/linux-container.scm (namespaces->bit-mask): Add
CLONE_CHILD_CLEARTID and CLONE_CHILD_SETTID to bit mask.
---
gnu/build/linux-container.scm | 3 ++-
guix/build/syscalls.scm | 16 ++++++++++------
2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/gnu/build/linux-container.scm b/gnu/build/linux-container.scm
index 4262748..80a8d94 100644
--- a/gnu/build/linux-container.scm
+++ b/gnu/build/linux-container.scm
@@ -162,7 +162,8 @@ host user identifiers to map into the user namespace."
(define (namespaces->bit-mask namespaces)
"Return the number suitable for the 'flags' argument of 'clone' that
corresponds to the symbols in NAMESPACES."
- (apply logior SIGCHLD
+ ;; Use the same flags as fork(3) in addition to the namespace flags.
+ (apply logior SIGCHLD CLONE_CHILD_CLEARTID CLONE_CHILD_SETTID
(map (match-lambda
('mnt CLONE_NEWNS)
('uts CLONE_NEWUTS)
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 093eb0a..2c2fbde 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -50,6 +50,8 @@
mkdtemp!
pivot-root
+ CLONE_CHILD_CLEARTID
+ CLONE_CHILD_SETTID
CLONE_NEWNS
CLONE_NEWUTS
CLONE_NEWIPC
@@ -303,12 +305,14 @@ string TMPL and return its file name. TMPL must end with
'XXXXXX'."
(pointer->string result)))))
;; Linux clone flags, from linux/sched.h
-(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 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.
