.tmp_depmod owned by root after modules_install

.tmp_depmod owned by root after modules_install

[Christian Kujau]

Hi,

when building a kernel with O=$DIR, I noticed that "modules_install" now 
creates files under $DIR as root:

$ sudo make -C /usr/local/src/linux-2.6-git O=$HOME/trash/tmp/. modules_install
[...]

When trying to build a new kernel, removing $DIR as a normal user does no 
longer work as everything under $HOME/trash/tmp/.tmp_depmod/ is now owned 
by root (because of the "sudo"). This did not occur before and may be a 
consequence of:

  commit bfe5424a8b31624e7a476f959d552999f931e7c7
  Author: Michal Marek <mmarek@suse.cz>
  Date:   Thu Jun 9 16:35:41 2011 +0200

    kbuild: Hack for depmod not handling X.Y versions

Can this be changed somehow so that "make modules_install" does not write 
anything under $DIR, as before?

Thanks,
Christian.
-- 
BOFH excuse #274:

It was OK before you touched it.

Re: .tmp_depmod owned by root after modules_install

[Christian Kujau]

ping?

On Mon, 4 Jul 2011 at 02:49, Christian Kujau wrote:
> Hi,
> 
> when building a kernel with O=$DIR, I noticed that "modules_install" now 
> creates files under $DIR as root:
> 
> $ sudo make -C /usr/local/src/linux-2.6-git O=$HOME/trash/tmp/. modules_install
> [...]
> 
> When trying to build a new kernel, removing $DIR as a normal user does no 
> longer work as everything under $HOME/trash/tmp/.tmp_depmod/ is now owned 
> by root (because of the "sudo"). This did not occur before and may be a 
> consequence of:
> 
>   commit bfe5424a8b31624e7a476f959d552999f931e7c7
>   Author: Michal Marek <mmarek@suse.cz>
>   Date:   Thu Jun 9 16:35:41 2011 +0200
> 
>     kbuild: Hack for depmod not handling X.Y versions
> 
> Can this be changed somehow so that "make modules_install" does not write 
> anything under $DIR, as before?
> 
> Thanks,
> Christian.
> -- 
> BOFH excuse #274:
> 
> It was OK before you touched it.
> 

-- 
BOFH excuse #188:

..disk or the processor is on fire.

[PATCH] kbuild: Do not write to builddir in modules_install

[Michal Marek]

Let depmod.sh create a temporary directory in /tmp instead of writing to
the build directory as root. The mktemp utility should be available on
any recent system (and there is already scripts/gen_initramfs_list.sh
relying on it).

Reported-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
---
 scripts/depmod.sh |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index 3b029cb..a272356 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh
@@ -21,13 +21,15 @@ fi
 # older versions of depmod require the version string to start with three
 # numbers, so we cheat with a symlink here
 depmod_hack_needed=true
-mkdir -p .tmp_depmod/lib/modules/$KERNELRELEASE
-if "$DEPMOD" -b .tmp_depmod $KERNELRELEASE 2>/dev/null; then
-	if test -e .tmp_depmod/lib/modules/$KERNELRELEASE/modules.dep -o \
-		-e .tmp_depmod/lib/modules/$KERNELRELEASE/modules.dep.bin; then
+tmp_dir=$(mktemp -d ${TMPDIR:-/tmp}/depmod.XXXXXX)
+mkdir -p "$tmp_dir/lib/modules/$KERNELRELEASE"
+if "$DEPMOD" -b "$tmp_dir" $KERNELRELEASE 2>/dev/null; then
+	if test -e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep" -o \
+		-e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep.bin"; then
 		depmod_hack_needed=false
 	fi
 fi
+rm -rf "$tmp_dir"
 if $depmod_hack_needed; then
 	symlink="$INSTALL_MOD_PATH/lib/modules/99.98.$KERNELRELEASE"
 	ln -s "$KERNELRELEASE" "$symlink"
-- 
1.7.5.4

Re: [PATCH] kbuild: Do not write to builddir in modules_install

[Américo Wang]

On Tue, Jul 12, 2011 at 7:39 PM, Michal Marek <mmarek@suse.cz> wrote:
> Let depmod.sh create a temporary directory in /tmp instead of writing to
> the build directory as root. The mktemp utility should be available on
> any recent system (and there is already scripts/gen_initramfs_list.sh
> relying on it).
>

Hmm, why not use $objtree/.tmp_depmod?

Re: [PATCH] kbuild: Do not write to builddir in modules_install

[Michal Marek]

On 13.7.2011 03:05, Américo Wang wrote:
> On Tue, Jul 12, 2011 at 7:39 PM, Michal Marek<mmarek@suse.cz>  wrote:
>> Let depmod.sh create a temporary directory in /tmp instead of writing to
>> the build directory as root. The mktemp utility should be available on
>> any recent system (and there is already scripts/gen_initramfs_list.sh
>> relying on it).
>>
>
> Hmm, why not use $objtree/.tmp_depmod?

That's how it was done before and it's broken. make modules_install is 
usually ran as root and there is no guarantee that root has write access 
to the build directory (it can be on nfs).

Michal

Re: [PATCH] kbuild: Do not write to builddir in modules_install

[Américo Wang]

On Wed, Jul 13, 2011 at 5:21 PM, Michal Marek <mmarek@suse.cz> wrote:
> On 13.7.2011 03:05, Américo Wang wrote:
>>
>> On Tue, Jul 12, 2011 at 7:39 PM, Michal Marek<mmarek@suse.cz>  wrote:
>>>
>>> Let depmod.sh create a temporary directory in /tmp instead of writing to
>>> the build directory as root. The mktemp utility should be available on
>>> any recent system (and there is already scripts/gen_initramfs_list.sh
>>> relying on it).
>>>
>>
>> Hmm, why not use $objtree/.tmp_depmod?
>
> That's how it was done before and it's broken. make modules_install is
> usually ran as root and there is no guarantee that root has write access to
> the build directory (it can be on nfs).

Hmm, this is reasonable. Then I am fine with this patch.

Thanks for explanation!

Re: [PATCH] kbuild: Do not write to builddir in modules_install

[Christian Kujau]

On Wed, 13 Jul 2011 at 19:22, Américo Wang wrote:
> >> Hmm, why not use $objtree/.tmp_depmod?
> >
> > That's how it was done before and it's broken. make modules_install is
> > usually ran as root and there is no guarantee that root has write access to
> > the build directory (it can be on nfs).
> 
> Hmm, this is reasonable. Then I am fine with this patch.

Tested here, works fine, even with a noexec-mounted $TMPDIR. Thanks!

Christian.
-- 
BOFH excuse #62:

need to wrap system in aluminum foil to fix problem