# abipkgdiff

## NAME



           abipkgdiff - compare ABIs of ELF files in software packages
    
           **abipkgdiff** compares the Application Binary Interfaces (ABI) of the
           ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\ binaries contained in two sets of software packages.  The
           software package formats currently supported are ]8;;https://en.wikipedia.org/wiki/Deb_%28file_format%29\_Deb_]8;;\, ]8;;https://en.wikipedia.org/wiki/RPM_Package_Manager\_RPM_]8;;\, ]8;;https://en.wikipedia.org/wiki/Tar_%28computing%29\_tar_]8;;\
           archives (either compressed or not) and plain directories that
           contain binaries.
    
           The ABI of the binaries contained in the second set of packages is
           compared against the ABI of the binaries contained in the first
           set of packages.
    
           For a comprehensive ABI change report that includes changes about
           function and variable sub-types, the two input package sets must
           be accompanied with their debug information packages that contain
           debug information either in ]8;;http://www.dwarfstd.org\_DWARF_]8;;\, ]8;;https://raw.githubusercontent.com/wiki/oracle/binutils-gdb/files/ctf-spec.pdf\_CTF_]8;;\ or in ]8;;https://docs.kernel.org/bpf/btf.html\_BTF_]8;;\ 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 ]8;;http://www.dwarfstd.org\_DWARF_]8;;\ format, if
           present, otherwise it compares binaries interfaces using debug
           information in ]8;;https://raw.githubusercontent.com/wiki/oracle/binutils-gdb/files/ctf-spec.pdf\_CTF_]8;;\ or in ]8;;https://docs.kernel.org/bpf/btf.html\_BTF_]8;;\ formats, if present. Finally, if no
           debug info in these formats is found, it only considers ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\
           symbols and report about their addition or removal.
    
           This tool uses the libabigail library to analyze the binary as
           well as its associated debug information.  Here is its general
           mode of operation.
    
           When instructed to do so, a binary and its associated debug
           information is read and analyzed.  To that effect, libabigail
           analyzes by default 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
           Application Binary Interface Corpus is constructed by only
           considering the subset of types reachable from interfaces
           associated to ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\ symbols that are defined and exported by the
           binary.  It's that final ABI corpus which libabigail considers as
           representing the ABI of the analyzed binary.
    
           Libabigail then has capabilities to generate textual
           representations of ABI Corpora, compare them, analyze their
           changes and report about them.
    


## INVOCATION



              abipkgdiff [options] <package1> <package2>
    
           **package1** and **package2** are the packages that contain the binaries
           to be compared.
    
           An alternate invocation style would be:
    
              abipkgdiff [options] --set1 <pkg1-v1> <pkg2-v1> <pkg3-v1> \
                                   --set2 <pkg1-v2> <pkg2-v2> <pkg3-v2>
    
           where the ABI of binaries contained in the second set of packages
           are compared against binaries contained in the first set of
           packages.
    


## ENVIRONMENT



           abipkgdiff loads two default _suppression specifications files_ ,
           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.
    


## OPTIONS



              • **--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 ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\
                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 ]8;;https://kernel.org/\_Linux_
                _Kernel_]8;;\.  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 ]8;;https://kernel.org/\_Linux Kernel_]8;;\.
    
              • **--btf**
                    This is used to compare packages with ]8;;https://docs.kernel.org/bpf/btf.html\_BTF_]8;;\ debug
                    information, if present.
    
              • **--ctf**
                    This is used to compare packages with ]8;;https://raw.githubusercontent.com/wiki/oracle/binutils-gdb/files/ctf-spec.pdf\_CTF_]8;;\ debug
                    information, if present.
    
              • **--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 ]8;;https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Devel_Packages\_Development Package_]8;;\ associated
                with the first package to be compared.  That ]8;;https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Devel_Packages\_Development_
                _Package_]8;;\ 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 ]8;;https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Devel_Packages\_Development Package_]8;;\ associated
                with the second package to be compared.  That ]8;;https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Devel_Packages\_Development_
                _Package_]8;;\ 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.
    
              • **--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 ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\ 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 ]8;;https://kernel.org/\_Linux_
                _Kernel_]8;;\.  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 ]8;;http://en.wikipedia.org/wiki/Executable_and_Linkable_Format\_ELF_]8;;\ symbols.
    
                Note that this option is turned on by default when analyzing
                the ]8;;https://kernel.org/\_Linux Kernel_]8;;\.  Otherwise, it's turned off by default.
    
              • **--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
                _exit code documentation_.
    
              • **--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
    
                    $
    
              • **--harmless**
    
                In the diff report, display only the _harmless_ 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.
    
              • **--help | -h**
    
                Display a short help about the command and exit.
    
              • **--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.
    
              • **--keep-tmp-files**
    
                Do not erase the temporary directory files that are created
                during the execution of the tool.
    
              • **--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.
    
              • **--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.
    
              • **--no-abignore**
    
                Do not search the package for the presence of suppression
                files.
    
              • **--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-added-syms**
    
                Do not show the list of functions, variables, or any symbol
                that was added.
    
              • **--no-assume-odr-for-cplusplus**
    
                When analysing a binary originating from C++ code using ]8;;http://www.dwarfstd.org\_DWARF_]8;;\
                debug information, libabigail assumes the ]8;;https://en.wikipedia.org/wiki/One_Definition_Rule\_One Definition Rule_]8;;\
                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-default-suppression**
    
                Do not load the _default suppression specification files_.
    
              • **--no-leverage-dwarf-factorization**
    
                When analysing a binary which ]8;;http://www.dwarfstd.org\_DWARF_]8;;\ debug information was
                processed with the ]8;;https://sourceware.org/dwz\_DWZ_]8;;\ 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.
    
              • **--no-linkage-name**
    
                In the resulting report, do not display the linkage names of
                the added, removed, or changed functions or variables.
    
              • **--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.
    
              • **--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.
    
              • **--no-show-locs**
                  Do not show information about where in the _second shared_
                  _library_ the respective type was changed.
    
              • **--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.
    
              • **--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.
    
              • **--show-bits**
    
                Show sizes and offsets in bits, not bytes.  This option is
                activated by default.
    
              • **--show-bytes**
    
                Show sizes and offsets in bytes, not bits.  By default, sizes
                and offsets are shown in bits.
    
              • **--show-dec**
    
                Show sizes and offsets in decimal base.  This option is
                activated by default.
    
              • **--show-hex**
    
                Show sizes and offsets in hexadecimal base.
    
              • **--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.
    
              • **--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.
    
              • **--redundant**
                  In the diff reports, do display redundant changes.  A
                  redundant change is a change that has been displayed
                  elsewhere in a given report.
    
              • **--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' ====
                    $
    
              • **--set1** <package1-path> <package2-path> <package2-path> ...
    
                Specifies the first set of packages whose binaries are to be
                compared against the second one.  Note that the second set of
                packages is to be specified using the option **--set2**.
    
              • **--set2** <package1-path> <package2-path> <package2-path> ...
    
                Specifies the second set of packages whose binaries are to be
                compared against the second one.  Note that the first set of
                packages is to be specified using the option **--set1**.
    
              • **--suppressions | --suppr** <_path-to-suppressions_ >
    
                Use a _suppression specification_ 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 _default suppression specification files_ are loaded .
    
              • _--version | -v_
    
                Display the version of the program and exit.
    
              • **--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.
    
              • **--verbose**
    
                Emit verbose progress messages.
    
              • **--verbose-diff**
    
                Emit timed verbose progress messages about the diffing
                process.  This option implies the --verbose one.
    


## 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 _abidiff tool_.
    


* * *