[Buildroot] [PATCH v7 03/18] core: re-enter make if $(CURDIR) or $(O) are not absolute canonical path

[Matthew Weber]

Yann, Samuel, All

On Tue, Mar 22, 2016 at 6:11 PM, Matthew Weber <matt at thewebers.ws> wrote:
> Yann, All
>
> On Tue, Mar 22, 2016 at 5:07 PM, Yann E. MORIN <yann.morin.1998 at free.fr> wrote:
>> Matthew, All,
>>
>> On 2016-03-20 20:45 -0500, Matthew Weber spake thusly:
>>> On Sun, Mar 20, 2016 at 8:44 PM, Matthew Weber <matt at thewebers.ws> wrote:
>>> > On Wed, Mar 9, 2016 at 4:58 PM, Samuel Martin <s.martin49 at gmail.com> wrote:
>>> >> When $(CURDIR) or $(O) contain symlinks (or mount-bind) in their path,
>>> >> they can be resolved differently, depending on each package build-system
>>> >> (whether it uses the given paths or get the absolute canonical ones).
>>> >>
>>> >> Thus, to make easier tracking down host machine paths leaking into the
>>> >> host, target or staging trees, the CURDIR and O variables are set to
>>> >> their absolute canonical paths.
>>> >>
>>> >> Note that this change takes care of the makefile wrapper installed in
>>> >> $(O) to avoid unneeded make recursion.
>>> >>
>>> >> Signed-off-by: Samuel Martin <s.martin49 at gmail.com>
>>> >>
>>> >> ---
>>> >> changes v6->v7:
>>> >> - none
>>> >>
>>> >> changes v5->v6:
>>> >> - new patch
>>> >> ---
>>> >>  Makefile | 22 ++++++++++++++++++----
>>> >>  1 file changed, 18 insertions(+), 4 deletions(-)
>>> >>
>>> >> diff --git a/Makefile b/Makefile
>>> >> index 98c8dc7..52a92f6 100644
>>> >> --- a/Makefile
>>> >> +++ b/Makefile
>>> >> @@ -26,16 +26,30 @@
>>> >>
>>> >>  # Trick for always running with a fixed umask
>>> >>  UMASK = 0022
>>> >> -ifneq ($(shell umask),$(UMASK))
>>> >> +
>>> >> +# Check if we need to re-enter make for one or several of the following reasons:
>>> >> +# 1- Wrong (too restrictive) umask:
>>> >> +#    This prevents Buildroot and packages from creating files and directories.
>>> >> +# 2- CWD (i.e. $(CURDIR)) not being the absolute canonical path:
>>> >> +#    This makes harder tracking and fixing host machine path leaks.
>>> >> +# 3- Output location (i.e. $(O)) not being the absolute canonical path:
>>> >> +#    This makes harder tracking and fixing host machine path leaks.
>>> >> +#
>>> >> +# Note:
>>> >> +# - remove the trailing '/.' from $(O) as it can be added by the makefile
>>> >> +#   wrapper installed in the $(O).
>>> >> +ifneq ($(shell umask):$(CURDIR):$(patsubst %/.,%,$(O)),$(UMASK):$(realpath $(CURDIR)):$(realpath $(O)))
>>> >>  .PHONY: _all $(MAKECMDGOALS)
>>> >>
>>> >>  $(MAKECMDGOALS): _all
>>> >>         @:
>>> >>
>>> >>  _all:
>>> >> -       @umask $(UMASK) && $(MAKE) --no-print-directory $(MAKECMDGOALS)
>>> >> +       umask $(UMASK) && \
>>> >> +               $(MAKE) -C $(realpath $(CURDIR)) --no-print-directory \
>>> >> +                       $(MAKECMDGOALS) O=$(realpath $(O))
>>> >
>>> > I've applied your v7 patches with these changes to the tip of
>>> > buildroot and currently run into the following error.  I'm still
>>> > poking around trying to understand why.
>>> >
>>> > $ make V=1 qemu_x86_defconfig
>>> > umask 0022 && \
>>> >         make -C /opt/buildroot --no-print-directory \
>>> >                 qemu_x86_defconfig O=
>>
>> Why are you opassing an empty O= option here?
>>
>
> I'm not passing the O= .
>
> However, if I modify the patch and remove that from the target in the
> Makefile ie. remove the "O=$(realpath $(O))" , things build ok.

I tested this tonight on another server with Make version 3.81 and
reproduced with a fresh buildroot checkout
(f34c69da2bfa2a485671dbbcf1ee24ad7409b63b) plus applying the commit
mentioned as the latest from Samuel's fork.

Same behavior, if I edit the Makefile and remove the "O=$(realpath
$(O))" , the defconfig sets up as expected