.. _abipkgdiff_label:
===========
abipkgdiff
===========
``abipkgdiff`` compares the Application Binary Interfaces (ABI) of the
`ELF`_ binaries contained in two software packages. The software
package formats currently supported are `Deb`_, `RPM`_, `tar`_
archives (either compressed or not) and plain directories that contain
binaries.
For a comprehensive ABI change report that includes changes about
function and variable sub-types, the two input packages must be
accompanied with their debug information packages that contain debug
information either in `DWARF`_, `CTF`_ or in `BTF`_ formats. Please
note however that some packages contain binaries that embed the debug
information directly in a section of said binaries. In those cases,
obviously, no separate debug information package is needed as the tool
will find the debug information inside the binaries.
By default, ``abipkgdiff`` uses debug information in `DWARF`_ format,
if present, otherwise it compares binaries interfaces using debug
information in `CTF`_ or in `BTF`_ formats, if present. Finally, if no
debug info in these formats is found, it only considers `ELF`_ symbols
and report about their addition or removal.
.. include:: tools-use-libabigail.txt
.. _abipkgdiff_invocation_label:
Invocation
==========
::
abipkgdiff [option] <package1> <package2>
``package1`` and ``package2`` are the packages that contain the
binaries to be compared.
Environment
===========
.. _abipkgdiff_default_supprs_label:
abipkgdiff loads two default :ref:`suppression specifications files
<suppr_spec_label>`, merges their content and use it to filter out ABI
change reports that might be considered as false positives to users.
* Default system-wide suppression specification file
It's located by the optional environment variable
LIBABIGAIL_DEFAULT_SYSTEM_SUPPRESSION_FILE. If that environment
variable is not set, then abipkgdiff tries to load the suppression file
$libdir/libabigail/libabigail-default.abignore. If that file is not
present, then no default system-wide suppression specification file
is loaded.
* Default user suppression specification file.
It's located by the optional environment
LIBABIGAIL_DEFAULT_USER_SUPPRESSION_FILE. If that environment
variable is not set, then abipkgdiff tries to load the suppression file
$HOME/.abignore. If that file is not present, then no default user
suppression specification is loaded.
In addition to those default suppression specification files,
abipkgdiff will also look inside the packages being compared and if it
sees a file that ends with the extension ``.abignore``, then it will
consider it as a suppression specification and it will combine it to the
default suppression specification that might be already loaded.
The user might as well use the ``--suppressions`` option (that is
documented further below) to provide a suppression specification.
.. _abipkgdiff_options_label:
Options
=======
* ``--help | -h``
Display a short help about the command and exit.
* `--version | -v`
Display the version of the program and exit.
* ``--debug-info-pkg1 | --d1`` <path>
For cases where the debug information for *package1* is split out
into a separate file, tells ``abipkgdiff`` where to find that
separate debug information package.
Note that the debug info for *package1* can have been split into
several different debug info packages. In that case, several
instances of this options can be provided, along with those
several different debug info packages.
* ``--debug-info-pkg2 | --d2`` <path>
For cases where the debug information for *package2* is split out
into a separate file, tells ``abipkgdiff`` where to find that
separate debug information package.
Note that the debug info for *package2* can have been split into
several different debug info packages. In that case, several
instances of this options can be provided, along with those
several different debug info packages.
* ``--devel-pkg1 | --devel1`` <path>
Specifies where to find the `Development Package`_ associated with
the first package to be compared. That `Development Package`_ at
``path`` should at least contain header files in which public
types exposed by the libraries (of the first package to be
compared) are defined. When this option is provided, the tool
filters out reports about ABI changes to types that are *NOT*
defined in these header files.
* ``--devel-pkg2 | --devel2`` <path>
Specifies where to find the `Development Package`_ associated with
the second package to be compared. That `Development Package`_ at
``path`` should at least contains header files in which public
types exposed by the libraries (of the second package to be
compared) are defined. When this option is provided, the tool
filters out reports about ABI changes to types that are *NOT*
defined in these header files.
* ``--drop-private-types``
This option is to be used with the ``--devel-pkg1`` and
``--devel-pkg2`` options. With this option, types that are *NOT*
defined in the headers are entirely dropped from the internal
representation build by Libabigail to represent the ABI. They
thus don't have to be filtered out from the final ABI change
report because they are not even present in Libabigail's
representation.
Without this option however, those private types are kept in the
internal representation and later filtered out from the report.
This options thus potentially makes Libabigail consume less
memory. It's meant to be mainly used to optimize the memory
consumption of the tool on binaries with a lot of publicly defined
and exported types.
* ``--dso-only``
Compare ELF files that are shared libraries, only. Do not compare
executable files, for instance.
* ``--private-dso``
By default, ``abipkgdiff`` does not compare DSOs that are private
to the RPM package. A private DSO is a DSO which SONAME is *NOT*
advertised in the "provides" property of the RPM.
This option instructs ``abipkgdiff`` to *also* compare DSOs that
are *NOT* advertised in the "provides" property of the RPM.
Please note that the fact that (by default) ``abipkgdiff`` skips
private DSO is a feature that is available only for RPMs, at the
moment. We would happily accept patches adding that feature for
other package formats.
* ``--leaf-changes-only|-l`` only show leaf changes, so don't show
impact analysis report. This option implies ``--redundant``
The typical output of ``abipkgdiff`` and ``abidiff`` when
comparing two binaries, that we shall call ``full impact report``,
looks like this ::
$ abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C]'function void fn(C&)' at test-v1.cc:13:1 has some indirect sub-type changes:
parameter 1 of type 'C&' has sub-type changes:
in referenced type 'struct C' at test-v1.cc:7:1:
type size hasn't changed
1 data member change:
type of 'leaf* C::m0' changed:
in pointed to type 'struct leaf' at test-v1.cc:1:1:
type size changed from 32 to 64 bits
1 data member insertion:
'char leaf::m1', at offset 32 (in bits) at test-v1.cc:4:1
$
So in that example the report emits information about how the data
member insertion change of "struct leaf" is reachable from
function "void fn(C&)". In other words, the report not only shows
the data member change on "struct leaf", but it also shows the
impact of that change on the function "void fn(C&)".
In abidiff (and abipkgdiff) parlance, the change on "struct leaf"
is called a leaf change. So the ``--leaf-changes-only
--impacted-interfaces`` options show, well, only the leaf change.
And it goes like this: ::
$ abidiff -l libtest-v0.so libtest-v1.so
'struct leaf' changed:
type size changed from 32 to 64 bits
1 data member insertion:
'char leaf::m1', at offset 32 (in bits) at test-v1.cc:4:1
one impacted interface:
function void fn(C&)
$
Note how the report ends up by showing the list of interfaces
impacted by the leaf change. That's the effect of the additional
``--impacted-interfaces`` option.
Now if you don't want to see that list of impacted interfaces,
then you can just avoid using the ``--impacted-interface`` option.
You can learn about that option below, in any case.
Please note that when comparing two Linux Kernel packages, it's
this ``leaf changes report`` that is emitted, by default. The
normal so-called ``full impact report`` can be emitted with the
option ``--full-impact`` which is documented later below.
* ``--impacted-interfaces``
When showing leaf changes, this option instructs abipkgdiff to
show the list of impacted interfaces. This option is thus to be
used in addition to the ``--leaf-changes-only`` option, or, when
comparing two Linux Kernel packages. Otherwise, it's simply
ignored.
* ``--full-impact|-f``
When comparing two Linux Kernel packages, this function instructs
``abipkgdiff`` to emit the so-called ``full impact report``, which
is the default report kind emitted by the ``abidiff`` tool: ::
$ abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C]'function void fn(C&)' at test-v1.cc:13:1 has some indirect sub-type changes:
parameter 1 of type 'C&' has sub-type changes:
in referenced type 'struct C' at test-v1.cc:7:1:
type size hasn't changed
1 data member change:
type of 'leaf* C::m0' changed:
in pointed to type 'struct leaf' at test-v1.cc:1:1:
type size changed from 32 to 64 bits
1 data member insertion:
'char leaf::m1', at offset 32 (in bits) at test-v1.cc:4:1
$
* ``--non-reachable-types|-t``
Analyze and emit change reports for all the types of the binary,
including those that are not reachable from global functions and
variables.
This option might incur some serious performance degradation as
the number of types analyzed can be huge. However, if paired with
the ``--devel-pkg{1,2}`` options, the additional non-reachable
types analyzed are restricted to those defined in the public
headers files carried by the referenced development packages, thus
hopefully making the performance hit acceptable.
Also, using this option alongside suppression specifications (by
also using the ``--suppressions`` option) might help keep the number of
analyzed types (and the potential performance degradation) in
control.
Note that without this option, only types that are reachable from
global functions and variables are analyzed, so the tool detects
and reports changes on these reachable types only.
* ``--exported-interfaces-only``
By default, when looking at the debug information accompanying a
binary, this tool analyzes the descriptions of the types reachable
by the interfaces (functions and variables) that are visible
outside of their translation unit. Once that analysis is done, an
ABI corpus is constructed by only considering the subset of types
reachable from interfaces associated to `ELF`_ symbols that are
defined and exported by the binary. It's those final ABI Corpora
that are compared by this tool.
The problem with that approach however is that analyzing all the
interfaces that are visible from outside their translation unit
can amount to a lot of data, especially when those binaries are
applications, as opposed to shared libraries. One example of such
applications is the `Linux Kernel`_. Analyzing massive ABI
corpora like these can be extremely slow.
To mitigate that performance issue, this option allows libabigail
to only analyze types that are reachable from interfaces
associated with defined and exported `ELF`_ symbols.
Note that this option is turned on by default when analyzing the
`Linux Kernel`_. Otherwise, it's turned off by default.
* ``--allow-non-exported-interfaces``
When looking at the debug information accompanying a binary, this
tool analyzes the descriptions of the types reachable by the
interfaces (functions and variables) that are visible outside of
their translation unit. Once that analysis is done, an ABI corpus
is constructed by only considering the subset of types reachable
from interfaces associated to `ELF`_ symbols that are defined and
exported by the binary. It's those final ABI Corpora that are
compared by this tool.
The problem with that approach however is that analyzing all the
interfaces that are visible from outside their translation unit
can amount to a lot of data, especially when those binaries are
applications, as opposed to shared libraries. One example of such
applications is the `Linux Kernel`_. Analyzing massive ABI
Corpora like these can be extremely slow.
In the presence of an "average sized" binary however one can
afford having libabigail analyze all interfaces that are visible
outside of their translation unit, using this option.
Note that this option is turned on by default, unless we are in
the presence of the `Linux Kernel`_.
* ``--redundant``
In the diff reports, do display redundant changes. A redundant
change is a change that has been displayed elsewhere in a given
report.
* ``--harmless``
In the diff report, display only the :ref:`harmless
<harmlesschangeconcept_label>` changes. By default, the harmless
changes are filtered out of the diff report keep the clutter to a
minimum and have a greater chance to spot real ABI issues.
* ``--no-linkage-name``
In the resulting report, do not display the linkage names of
the added, removed, or changed functions or variables.
* ``--no-added-syms``
Do not show the list of functions, variables, or any symbol that
was added.
* ``--no-added-binaries``
Do not show the list of binaries that got added to the second
package.
Please note that the presence of such added binaries is not
considered like an ABI change by this tool; as such, it doesn't
have any impact on the exit code of the tool. It does only have
an informational value. Removed binaries are, however, considered
as an ABI change.
* ``--no-abignore``
Do not search the package for the presence of suppression files.
* ``--no-parallel``
By default, ``abipkgdiff`` will use all the processors it has available to
execute concurrently. This option tells it not to extract packages or run
comparisons in parallel.
* ``--no-default-suppression``
Do not load the :ref:`default suppression specification files
<abipkgdiff_default_supprs_label>`.
* ``--suppressions | --suppr`` <*path-to-suppressions*>
Use a :ref:`suppression specification <suppr_spec_label>` file
located at *path-to-suppressions*. Note that this option can
appear multiple times on the command line. In that case, all of
the suppression specification files are taken into account.
Please note that, by default, if this option is not provided, then
the :ref:`default suppression specification files
<abipkgdiff_default_supprs_label>` are loaded .
* ``--linux-kernel-abi-whitelist | -w`` <*path-to-whitelist*>
When comparing two Linux kernel RPM packages, this option points
to the white list of names of ELF symbols of functions and
variables that must be compared for ABI changes. That white list
is called a "Linux kernel ABI white list".
Any other function or variable which ELF symbol are not present in
that white list will not be considered by the ABI comparison
process.
If this option is not provided -- thus if no white list is
provided -- then the ABI of all publicly defined and exported
functions and global variables by the Linux Kernel binaries are
compared.
Please note that if a white list package is given in parameter,
this option handles it just fine, like if the --wp option was
used.
* ``--wp`` <*path-to-whitelist-package*>
When comparing two Linux kernel RPM packages, this option points
an RPM package containining several white lists of names of ELF
symbols of functions and variables that must be compared for ABI
changes. Those white lists are called "Linux kernel ABI white
lists".
From the content of that white list package, this program then
chooses the appropriate Linux kernel ABI white list to consider
when comparing the ABI of Linux kernel binaries contained in the
Linux kernel packages provided on the command line.
That choosen Linux kernel ABI white list contains the list of
names of ELF symbols of functions and variables that must be
compared for ABI changes.
Any other function or variable which ELF symbol are not present in
that white list will not be considered by the ABI comparison
process.
Note that this option can be provided twice (not mor than twice),
specifying one white list package for each Linux Kernel package
that is provided on the command line.
If this option is not provided -- thus if no white list is
provided -- then the ABI of all publicly defined and exported
functions and global variables by the Linux Kernel binaries are
compared.
* ``--no-unreferenced-symbols``
In the resulting report, do not display change information about
function and variable symbols that are not referenced by any debug
information. Note that for these symbols not referenced by any
debug information, the change information displayed is either
added or removed symbols.
* ``--no-show-locs``
Do not show information about where in the *second shared library*
the respective type was changed.
* ``--show-bytes``
Show sizes and offsets in bytes, not bits. By default, sizes and
offsets are shown in bits.
* ``--show-bits``
Show sizes and offsets in bits, not bytes. This option is
activated by default.
* ``--show-hex``
Show sizes and offsets in hexadecimal base.
* ``--show-dec``
Show sizes and offsets in decimal base. This option is activated
by default.
* ``--no-show-relative-offset-changes``
Without this option, when the offset of a data member changes,
the change report not only mentions the older and newer offset,
but it also mentions by how many bits the data member changes.
With this option, the latter is not shown.
* ``--show-identical-binaries``
Show the names of the all binaries compared, including the
binaries whose ABI compare equal. By default, when this option is
not provided, only binaries with ABI changes are mentionned in the
output.
* ``--fail-no-dbg``
Make the program fail and return a non-zero exit code if couldn't
read any of the debug information that comes from the debug info
packages that were given on the command line. If no debug info
package were provided on the command line then this option is not
active.
Note that the non-zero exit code returned by the program as a
result of this option is the constant ``ABIDIFF_ERROR``. To know
the numerical value of that constant, please refer to the
:ref:`exit code documentation <abidiff_return_value_label>`.
* ``--keep-tmp-files``
Do not erase the temporary directory files that are created during
the execution of the tool.
* ``--verbose``
Emit verbose progress messages.
* ``--self-check``
This is used to test the underlying Libabigail library. When in
used, the command expects only on input package, along with its
associated debug info packages. The command then compares each
binary inside the package against its own ABIXML
representation. The result of the comparison should yield the
empty set if Libabigail behaves correctly. Otherwise, it means
there is an issue that ought to be fixed. This option is used by
people interested in Libabigail development for regression testing
purposes. Here is an example of the use of this option: ::
$ abipkgdiff --self-check --d1 mesa-libGLU-debuginfo-9.0.1-3.fc33.x86_64.rpm mesa-libGLU-9.0.1-3.fc33.x86_64.rpm
==== SELF CHECK SUCCEEDED for 'libGLU.so.1.3.1' ====
$
* ``--no-assume-odr-for-cplusplus``
When analysing a binary originating from C++ code using `DWARF`_
debug information, libabigail assumes the `One Definition Rule`_
to speed-up the analysis. In that case, when several types have
the same name in the binary, they are assumed to all be equal.
This option disables that assumption and instructs libabigail to
actually actually compare the types to determine if they are
equal.
* ``--no-leverage-dwarf-factorization``
When analysing a binary which `DWARF`_ debug information was
processed with the `DWZ`_ tool, the type information is supposed
to be already factorized. That context is used by libabigail to
perform some speed optimizations.
This option disables those optimizations.
* ``--ctf``
This is used to compare packages with `CTF`_ debug information,
if present.
* ``--btf``
This is used to compare packages with `BTF`_ debug information,
if present.
.. _abipkgdiff_return_value_label:
Return value
============
The exit code of the ``abipkgdiff`` command is either 0 if the ABI of
the binaries compared are equal, or non-zero if they differ or if the
tool encountered an error.
In the later case, the value of the exit code is the same as for the
:ref:`abidiff tool <abidiff_return_value_label>`.
.. _ELF: http://en.wikipedia.org/wiki/Executable_and_Linkable_Format
.. _RPM: https://en.wikipedia.org/wiki/RPM_Package_Manager
.. _Deb: https://en.wikipedia.org/wiki/Deb_%28file_format%29
.. _tar: https://en.wikipedia.org/wiki/Tar_%28computing%29
.. _DWARF: http://www.dwarfstd.org
.. _CTF: https://raw.githubusercontent.com/wiki/oracle/binutils-gdb/files/ctf-spec.pdf
.. _BTF: https://docs.kernel.org/bpf/btf.html
.. _Development Package: https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Devel_Packages
.. _ODR: https://en.wikipedia.org/wiki/One_Definition_Rule
.. _One Definition Rule: https://en.wikipedia.org/wiki/One_Definition_Rule
.. _DWZ: https://sourceware.org/dwz
.. _Linux Kernel: https://kernel.org/