So far create-diff-object worked only with objectfiles built from a
single source file. To support object-files built from multiple sources
such as linked vmlinux.o, we call locals_match() for each of STT_FILE
symbols and store the pointer to the beginning of appropriate symbol
block in lookup table in each symbol.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
At the moment lookup_symbol() takes symbol name as an argument which
might not be enough in some cases (e.g. for objectfiles built from
multiple source files). Make it accept full symbol structure.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
The dynrela (aka .klp.rela) conversion logic is notoriously complex and
fragile. Simplify it and improve the comments.
This is mainly a cosmetic change. In theory it shouldn't change
functionality or break anything.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
create-diff-object doesn't really need the full kernel object file as
input. All it requires is a symbol table. Switch to using "eu-readelf -s"'s
output instead of object files. This will enable us to cover more cases
in unit tests.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Artem Savkov <asavkov@redhat.com>
We use kelf_base->symbols to find a unique matching FILE+locals combination
when we call lookup_open(). If we can't find one matching or we find more
than one matching, we error out.
If we find a unique one, we setup table->local_syms in lookup_open(),
so later lookup_local_symbol() could do its lookup based on table->local_syms.
Fixes#604.
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Have lookup_open() also parse Module.symvers and add the resulting symbols
and their objnames to the lookup table. This code was essentially
cherry-picked from Josh Poimboeuf's lookup code found here:
8cdca59c88
That patch was modified to fix a bug in obj_read() (calling elf_end()
without strdup'ing the symbol name strings, which was causing null
dereferences) and to fix up the module name after reading it from
Module.symvers (replacing '-' with '_' and stripping the path prefixes).
Also, add lookup_exported_symbol_objname(), which looks up the objname of
an exported symbol by making use of the objname information obtained from
Module.symvers.
Support patching objects that have duplicated function names. This feature was
introduced upstream in Linux v4.5.
This patch appends the symbol position to the symbol structure when
lookup_local_symbol is called. This pos variable is then used when creating the
funcs and dynrelas sections. Finally, incorporate sympos into the livepatch
patch hook only if the kernel version is greater than v4.5. In other cases the
older format is used.
Fixes: #493
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
In preparation for dynamic symbol linking, the symbol lookup logic
is going to move into create-diff-obj anyway. We might as well
minimize the code duplication and pull this into create-diff-obj.
This avoids having to re-parse the ELF file modify it in-place.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Conflicts:
kpatch-build/kpatch-build
We merged PR #186 a little too hastily. It seg faults with the new
parainstructions-section.patch in the integration test suite. Reverting
it for now until we get it figured out.
This reverts commit e1177e3a03.
This reverts commit 880e271841.
This reverts commit 2de5f6cbfb.
This reverts commit 38b7ac74ad.
This reverts commit 108cd9f95e.
In preparation for dynamic symbol linking, the symbol lookup logic
is going to move into create-diff-obj anyway. We might as well
minimize the code duplication and pull this into create-diff-obj.
This avoids having to re-parse the ELF file modify it in-place.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
