Re: [libbacktrace] Fix and simplify xcoff_%.c pattern rule

[Ian Lance Taylor <iant@golang.org>]

On Mon, Jan 28, 2019 at 1:25 AM Tom de Vries <tdevries@suse.de> wrote:
>
> [ was: Re: [backtrace] Avoid segfault  ]
> On 27-01-19 22:53, Ian Lance Taylor wrote:
> > On Sun, Jan 27, 2019 at 1:16 PM Tom de Vries <tdevries@suse.de> wrote:
> >>
> >> On 25-01-19 18:15, Nathan Sidwell wrote:
> >>> On 1/25/19 5:28 AM, Tom de Vries wrote:
> >>>>
> >>>> This patch fixes it by passing "" instead of NULL, in the call to
> >>>> elf_add at line 3083 (for .gnu_debugaltlink), not the call to elf_add at
> >>>> line 3044 (for .gnu_debuglink) mentioned above.
> >>>>
> >>>> Nathan, does this fix the problem for you? If not, can you provide a
> >>>> reproducer, or give a hint on how one could be constructed?
> >>>
> >>> I still hit the problem, and am installing this as sufficiently obvious.
> >>>  I'm on a fedora system debugging pr88995.  The debuglink_name is
> >>> "../../.dwz/isl-0.16.1-7.fc29.x86_64"
> >>>
> >>
> >> I've managed to reproduce this segfault instance by adding a test-case
> >> that uses both build-id and dwz.
> >>
> >> OK for trunk?
> >
> >> +elf_for_test.c: elf.c
> >> + PWD=$$(pwd -P); \
> >> + BUILD_ID_DIR="usr/lib/debug/.build-id/"; \
> >> + SEARCH='#define SYSTEM_BUILD_ID_DIR'; \
> >> + REPLACE="#define SYSTEM_BUILD_ID_DIR \"$$PWD/$$BUILD_ID_DIR\""; \
> >> + $(SED) "s%^$$SEARCH.*\$$%$$REPLACE%" \
> >> + $< \
> >> + > $@
> >
> > You need to use a temporary file, such as $@.tmp, for the final sed
> > command, followed by a mv to $@.  Otherwise a failure in the sed will
> > leave what appears to be an up to date file.
>
> I noticed the same problem in the xcoff_%.c pattern rule.
>
> OK for trunk?

This is OK.

Thanks.

Ian