abipkgdiff man page

abipkgdiff — compare ABIs of ELF files in software packages

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 in DWARF format.

Invocation

abipkgdiff [option] <package1> <package2>

package1 and package2 are the packages that contain the binaries to be compared.

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.

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.

  • --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.

  • --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.

  • --leaf-changes-only|-l only show leaf changes, so don’t show impact analysis report.

    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
    
    $
  • --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 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.

  • --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 package2 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 default suppression specification files.

  • --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 .

  • --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.

  • --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 exit code documentation.

  • --keep-tmp-files

    Do not erase the temporary directory files that are created during the execution of the tool.

  • --verbose

    Emit verbose progress messages.

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.

Author

Dodji Seketeli

Referenced By

rebase-helper(1).

Nov 22, 2017 Libabigail