* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
@ 2014-12-23 10:44 Nicolas Cavallari
2014-12-23 11:20 ` Thomas Petazzoni
2014-12-26 20:02 ` Thomas Petazzoni
0 siblings, 2 replies; 6+ messages in thread
From: Nicolas Cavallari @ 2014-12-23 10:44 UTC (permalink / raw)
To: buildroot
nsenter is a tool to enter the namespace of another process.
Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
---
package/util-linux/Config.in | 5 +++++
package/util-linux/util-linux.mk | 1 +
2 files changed, 6 insertions(+)
diff --git a/package/util-linux/Config.in b/package/util-linux/Config.in
index 5dfd050..2f23419 100644
--- a/package/util-linux/Config.in
+++ b/package/util-linux/Config.in
@@ -118,6 +118,11 @@ config BR2_PACKAGE_UTIL_LINUX_MESG
help
Control write access to your terminal
+config BR2_PACKAGE_UTIL_LINUX_NSENTER
+ bool "nsenter"
+ help
+ Enter the namespaces of another process.
+
config BR2_PACKAGE_UTIL_LINUX_MOUNT
bool "mount/umount"
help
diff --git a/package/util-linux/util-linux.mk b/package/util-linux/util-linux.mk
index e06fa9a..a530596 100644
--- a/package/util-linux/util-linux.mk
+++ b/package/util-linux/util-linux.mk
@@ -74,6 +74,7 @@ UTIL_LINUX_CONF_OPTS += \
$(if $(BR2_PACKAGE_UTIL_LINUX_LOGIN_UTILS),--enable-last --enable-login --enable-su --enable-sulogin,--disable-last --disable-login --disable-su --disable-sulogin) \
$(if $(BR2_PACKAGE_UTIL_LINUX_LOSETUP),--enable-losetup,--disable-losetup) \
$(if $(BR2_PACKAGE_UTIL_LINUX_MESG),--enable-mesg,--disable-mesg) \
+ $(if $(BR2_PACKAGE_UTIL_LINUX_NSENTER),--enable-nsenter,--disable-nsenter) \
$(if $(BR2_PACKAGE_UTIL_LINUX_MOUNT),--enable-mount,--disable-mount) \
$(if $(BR2_PACKAGE_UTIL_LINUX_NEWGRP),--enable-newgrp,--disable-newgrp) \
$(if $(BR2_PACKAGE_UTIL_LINUX_PARTX),--enable-partx,--disable-partx) \
--
2.1.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
2014-12-23 10:44 [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary Nicolas Cavallari
@ 2014-12-23 11:20 ` Thomas Petazzoni
2014-12-23 12:33 ` Nicolas Cavallari
2014-12-26 20:02 ` Thomas Petazzoni
1 sibling, 1 reply; 6+ messages in thread
From: Thomas Petazzoni @ 2014-12-23 11:20 UTC (permalink / raw)
To: buildroot
Dear Nicolas Cavallari,
On Tue, 23 Dec 2014 11:44:10 +0100, Nicolas Cavallari wrote:
> nsenter is a tool to enter the namespace of another process.
>
> Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
> ---
> package/util-linux/Config.in | 5 +++++
> package/util-linux/util-linux.mk | 1 +
> 2 files changed, 6 insertions(+)
We had this option in the past, but it was causing some problems with a
number of toolchains, so we had to revert it. See:
http://git.buildroot.net/buildroot/commit/package/util-linux?id=d293e64bfb75c4cbaab7e46472de674ee813d4aa
Has this issue been resolved?
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
2014-12-23 11:20 ` Thomas Petazzoni
@ 2014-12-23 12:33 ` Nicolas Cavallari
0 siblings, 0 replies; 6+ messages in thread
From: Nicolas Cavallari @ 2014-12-23 12:33 UTC (permalink / raw)
To: buildroot
On 23/12/2014 12:20, Thomas Petazzoni wrote:
> Dear Nicolas Cavallari,
>
> We had this option in the past, but it was causing some problems with a
> number of toolchains, so we had to revert it. See:
>
> http://git.buildroot.net/buildroot/commit/package/util-linux?id=d293e64bfb75c4cbaab7e46472de674ee813d4aa
I didn't know. It was compiling fine with uclibc. Now I realize that
uclibc does not provide setns()...
> Has this issue been resolved?
Yes, there is a fallback in util-linux sources:
# if !defined(HAVE_SETNS) && defined(SYS_setns)
static inline int setns(int fd, int nstype)
{
return syscall(SYS_setns, fd, nstype);
}
# endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
2014-12-23 10:44 [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary Nicolas Cavallari
2014-12-23 11:20 ` Thomas Petazzoni
@ 2014-12-26 20:02 ` Thomas Petazzoni
2014-12-26 20:45 ` Nicolas Cavallari
1 sibling, 1 reply; 6+ messages in thread
From: Thomas Petazzoni @ 2014-12-26 20:02 UTC (permalink / raw)
To: buildroot
Dear Nicolas Cavallari,
On Tue, 23 Dec 2014 11:44:10 +0100, Nicolas Cavallari wrote:
> nsenter is a tool to enter the namespace of another process.
>
> Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
> ---
> package/util-linux/Config.in | 5 +++++
> package/util-linux/util-linux.mk | 1 +
> 2 files changed, 6 insertions(+)
Thanks, applied after adding a Config.in condition to make sure that we
don't enable this option if we have kernel headers older than 3.0: the
setns() system call was added in Linux 3.0.
Thanks,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
2014-12-26 20:02 ` Thomas Petazzoni
@ 2014-12-26 20:45 ` Nicolas Cavallari
2014-12-26 20:57 ` Thomas Petazzoni
0 siblings, 1 reply; 6+ messages in thread
From: Nicolas Cavallari @ 2014-12-26 20:45 UTC (permalink / raw)
To: buildroot
On 26/12/2014 21:02, Thomas Petazzoni wrote:
> Dear Nicolas Cavallari,
>
> On Tue, 23 Dec 2014 11:44:10 +0100, Nicolas Cavallari wrote:
>> nsenter is a tool to enter the namespace of another process.
>>
>> Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
>> ---
>> package/util-linux/Config.in | 5 +++++
>> package/util-linux/util-linux.mk | 1 +
>> 2 files changed, 6 insertions(+)
>
> Thanks, applied after adding a Config.in condition to make sure that we
> don't enable this option if we have kernel headers older than 3.0: the
> setns() system call was added in Linux 3.0.
I'm not so sure now ... The fallback uses SYS_netns, instead of the
kernel's __NR_setns, so i assume that there must be some C library
support ... uclibc does define SYS_netns to be __NR_setns, so i think
the problem is still valid if the toolchain does not define SYS_setns.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary.
2014-12-26 20:45 ` Nicolas Cavallari
@ 2014-12-26 20:57 ` Thomas Petazzoni
0 siblings, 0 replies; 6+ messages in thread
From: Thomas Petazzoni @ 2014-12-26 20:57 UTC (permalink / raw)
To: buildroot
Dear Nicolas Cavallari,
On Fri, 26 Dec 2014 21:45:42 +0100, Nicolas Cavallari wrote:
> I'm not so sure now ... The fallback uses SYS_netns, instead of the
> kernel's __NR_setns, so i assume that there must be some C library
> support ... uclibc does define SYS_netns to be __NR_setns, so i think
> the problem is still valid if the toolchain does not define SYS_setns.
I was also confused by this, but it's actually util-linux itself that
defines SYS_setns from __NR_setns.
From m4/ul.m4 in util-linux sources:
AC_DEFUN([UL_CHECK_SYSCALL], [
dnl This macro uses host_cpu.
AC_REQUIRE([AC_CANONICAL_HOST])
AC_CACHE_CHECK([for syscall $1],
[ul_cv_syscall_$1],
[_UL_SYSCALL_CHECK_DECL([SYS_$1],
[syscall=SYS_$1],
[dnl Our libc failed use, so see if we can get the kernel
dnl headers to play ball ...
_UL_SYSCALL_CHECK_DECL([_NR_$1],
[syscall=_NR_$1],
[
syscall=no
if test "x$linux_os" = xyes; then
case $host_cpu in
_UL_CHECK_SYSCALL_FALLBACK(m4_shift($@))
esac
fi
])
])
ul_cv_syscall_$1=$syscall
])
AM_CONDITIONAL([HAVE_]m4_toupper($1), [test "x$ul_cv_syscall_$1" != xno])
case $ul_cv_syscall_$1 in #(
no) AC_MSG_WARN([Unable to detect syscall $1.]) ;;
SYS_*) ;;
*) AC_DEFINE_UNQUOTED([SYS_$1], [$ul_cv_syscall_$1],
[Fallback syscall number for $1]) ;;
esac
])
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 6+ messages in thread
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2014-12-23 10:44 [Buildroot] [PATCH 1/1] util-linux: Add an option to compile 'nsenter' binary Nicolas Cavallari
2014-12-23 11:20 ` Thomas Petazzoni
2014-12-23 12:33 ` Nicolas Cavallari
2014-12-26 20:02 ` Thomas Petazzoni
2014-12-26 20:45 ` Nicolas Cavallari
2014-12-26 20:57 ` Thomas Petazzoni
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