On Tue, 2014-04-22 at 09:33 +0200, Florian Weimer wrote:
> On 04/18/2014 01:02 PM, Mark Wielaard wrote:
> > On Tue, 2014-04-15 at 14:49 +0200, Florian Weimer wrote:
> >> +2014-04-15 Florian Weimer <fwei...@redhat.com>
> >> +
> >> + * dwelf_dwarf_gnu_debugaltlink.c: New file.
> >> + * Makefile.am (libdwelf_a_SOURCES): Add it.
> >> + * libdwelf.h (dwelf_dwarf_gnu_debugaltlink): Declare new function.
> >> + * libdwelfP.h (dwelf_dwarf_gnu_debugaltlink): Add internal
> >> + declaration.
> >
> > The code looks fine. But I still like the "tri-state" return more to
> > indicate why/how things went. Precisely because then you don't have to
> > do:
> >
> >> + Elf_Data *data = dwarf->sectiondata[IDX_gnu_debugaltlink];
> >> + if (data == NULL)
> >> + {
> >> + /* Missing data is not actually an error. */
> >> + __libdw_seterrno (0);
> >> + return NULL;
> >> + }
> >> [...]
> >> +/* Returns the name of the alternate debug information file from the
> >> + .gnu_debugaltlink section if found in the ELF. On success, writes
> >> + a pointer to the build ID to *BUILD_IDP, and its length to
> >> + *BUILD_ID_LENP. Returns NULL if the ELF file didn't have a
> >> + .gnu_debuglink section (and sets the dwarf_errcode error code to
> >> + 0), had malformed data in the section or some other error occured.
> >> + The returned pointers are valid while the ELF handle is valid. */
> >> +extern const char *dwelf_dwarf_gnu_debugaltlink (Dwarf *dwarf,
> >> + const void **build_idp,
> >> + size_t *build_id_lenp);
>
> I'm not sure if this addresses this completely addresses the issue. A
> return value of 0 could mean "no debugaltlink data" or "the build ID has
> zero length".
But a zero length build ID isn't valid, so then you would just return -1
and set DWARF_E_INVALID_ELF.
> > Thanks for adding the testcase. run-debugaltlink.sh should also be added
> > to EXTRA_DIST (I also forgot that in my dwelf_elf_gnu_debuglink patch
> > (fixed on the mjw/dwelf branch).
>
> Can't we handle this in a better way with make variables, so that the
> file needs to be listed in just one place?
Yeah we probably should, I have forgotten more than once.
Cheers,
Mark
