What’s New in 11.2: Install Debuginfo Package by build-id

Jan Blunck — Mon, 27 Apr 2009 09:37:50 +0000

With the help of a unique identifier that is stored in every binary executable matching the executable, a coredump and the corresponding debuginfo together becomes really easy. You don’t need to know the package name and the version-release string to download and install the correct debuginfo package. This is achieved by extending the linker, some additional tools and the package management itself.

The build id is a unique identifier stored in the .note.gnu.build-id note section of the executable file and loaded into the process image during run-time. Different means to compute the unique identifier are supported although the default setting is to use a 20 byte SHA1 hash of the unstripped executable (see ld linker documentation for further information about the –build-id option).

To be able to read the build id from a core dump the kernel must include the ELF header pages in file-backed private memory areas (see documentation on /proc//coredump_filter). This is the default setting on recent openSUSE kernel versions.

Different tools can be used to print out the build-id. eu-readelf (from the elfutils package) prints the contents of the note sections given the -n option in a human readable fashion. pbuildid (from the ptools package) is prints the build-id from executables and from core files including the build-id of all loaded shared objects during the crash.

Now, zypper can be asked to install the debuginfo package that provides the debuginfo for the given build-id.

# zypper install -C "debuginfo(build-id)=b75bab63c9a25eb13264bb95f1fef190e157f865"
Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following NEW package is going to be installed:
  bash-debuginfo


Overall download size: 605.0 K. After the operation, additional 2.1 M will be used.
Continue? [YES/no]: yes
Retrieving package bash-debuginfo-3.2-148.2.x86_64 (1/1), 605.0 K (2.1 M unpacked)
Retrieving: bash-debuginfo-3.2-148.2.x86_64.rpm [done]
Installing: bash-debuginfo-3.2-148.2 [done]
#

If you are really lazy you can call the following script to do the job for you:

#!/bin/bash                                                                     
#                                                                               
# Sample script how to install debuginfo packages by build-id                   
#                                                                               

IDS=''
for f in "$*"; do
    case "$(file -L $f)" in
        *ELF*)
            IDS+="$(pbuildid $f 2>/dev/null | awk '{print $NF}') "
            ;;
        *)  
            ;;
    esac
done

echo "Install Debuginfo for following build-ids: $IDS"

CMDLINE=""
for i in $IDS; do
    CMDLINE+="debuginfo(build-id)=$i "
done

echo $CMDLINE | xargs zypper install -C

debugging – openSUSE Lizards

What’s New in 11.2: Install Debuginfo Package by build-id