Visualize dependencies of binaries and libraries on Linux

Update4: Albert Astals Cid mentioned that KDE maintains also a version of that script: draw_lib_dependencies

Update3: Marco Nelissen fixed an issue, that caused dependency resolution to break, as soon MAXDEPTH was reached once. This issue was fixed now and I am quite happy that this old script is still useful and even get's improved. The updated version can also be found at dependencies.sh. Version below fixed as well.

Update2: pfee made some more fixes. The script parses now the dependcies tree correctly using readelf and ldd so that only direct dependencies apear in the graph. The updated version can also be found at dependencies.sh

Update: Thanks to the feedback from pfee, I made some fixes to the script. The script is now also available for direct download dependencies.sh

Sometimes it is useful to know the library dependencies of an application or a library on Linux (or Unix). Especially OpenSource applications depend on lot's of libraries which in turn depend on other libraries again. So it is not always quite clear which dependencies your software has.

Imagine you want to package up your software for a customer and need to know on which libraries your software depends. Usually you know which libraries were used during development, but what are the dependencies of these libraries? You have to package all dependencies so that the customer can use and/or install your software.

I created a bash-script which uses ldd to find the dependencies of a binary on Linux and Graphviz to create a dependency graph out of this information. Benedikt Hauptmann had the idea to show dependencies as a graph - so I cannot take credits for that. Using this script I created the depency graph of TFORMer, the report generator we are developing at TEC-IT. The result is a nice graph showing all the dependencies a user has to have installed before using TFORMer.

Another beautiful graph is the one of PoDoFo. See below the graph of PoDoFo.

The dependencies of Firefox are way more complex than the examples shown above...

If you want to create a graph of your favorite application or library your self, get the script from here. I pulished the simple source code below. Graphviz is the only requirement. Usage is very simple, just pass an application or library as first parameter and the output image as second argument. The script will always create a PNG image:

./dependencies.sh /usr/bin/emacs emacs.png
./dependencies.sh /usr/local/lib/libpodofo.so \
                  podofo.png

The code of the script is as follows: (Warning: the style sheet cuts of some lines, so better download the script from dependencies.sh)

#!/bin/bash
 
# This is the maximum depth to which dependencies are resolved
MAXDEPTH=14
 
# analyze a given file on its
# dependecies using ldd and write
# the results to a given temporary file
#
# Usage: analyze [OUTPUTFILE] [INPUTFILE]
function analyze
{
    local OUT=$1
    local IN=$2
    local NAME=$(basename $IN)
 
    for i in $LIST
    do
        if [ "$i" == "$NAME" ];
        then
            # This file was already parsed
            return
        fi
    done
    # Put the file in the list of all files
    LIST="$LIST $NAME"
 
    DEPTH=$[$DEPTH + 1]
    if [ $DEPTH -ge $MAXDEPTH ];
        then
        echo "MAXDEPTH of $MAXDEPTH reached at file $IN."
        echo "Continuing with next file..."

 # Fix by Marco Nelissen for the case that MAXDEPTH was reached

 DEPTH=$[$DEPTH - 1]
        return
    fi
 
    echo "Parsing file:              $IN"
 
    $READELF $IN &> $READELFTMPFILE
    ELFRET=$?
 
    if [ $ELFRET != 0 ];
        then
        echo "ERROR: ELF reader returned error code $RET"
        echo "ERROR:"
        cat $TMPFILE
        echo "Aborting..."
        rm $TMPFILE
        rm $READELFTMPFILE
        rm $LDDTMPFILE
        exit 1
    fi
 
    DEPENDENCIES=$(cat $READELFTMPFILE | grep NEEDED | awk '{if (substr($NF,1,1) == "[") print substr($NF, 2, length($NF) - 2); else print $NF}')
 
    for DEP in $DEPENDENCIES;
    do
        if [ -n "$DEP" ];
        then
 
            ldd $IN &> $LDDTMPFILE
            LDDRET=$?
 
            if [ $LDDRET != 0 ];
                then
                echo "ERROR: ldd returned error code $RET"
                echo "ERROR:"
                cat $TMPFILE
                echo "Aborting..."
                rm $TMPFILE
                rm $READELFTMPFILE
                rm $LDDTMPFILE
                exit 1
            fi
 
            DEPPATH=$(grep $DEP $LDDTMPFILE | awk '{print $3}')
            if [ -n "$DEPPATH" ];
            then
                echo -e "  \"$NAME\" -> \"$DEP\";" >> $OUT
                analyze $OUT $DEPPATH
            fi
        fi
    done
 
    DEPTH=$[$DEPTH - 1]
}
 ########################################
# main                                 #
########################################
 if [ $# != 2 ];
    then
    echo "Usage:"
    echo "  $0 [filename] [outputimage]"
    echo ""
    echo "This tools analyses a shared library or an executable"
    echo "and generates a dependency graph as an image."
    echo ""
    echo "GraphViz must be installed for this tool to work."
    echo ""
    exit 1
fi
 DEPTH=0
INPUT=$1
OUTPUT=$2
TMPFILE=$(mktemp -t)
LDDTMPFILE=$(mktemp -t)
READELFTMPFILE=$(mktemp -t)
LIST=""
 if [ ! -e $INPUT ];
    then
    echo "ERROR: File not found: $INPUT"
    echo "Aborting..."
    exit 2
fi
 # Use either readelf or dump
# Linux has readelf, Solaris has dump
READELF=$(type readelf 2> /dev/null)
if [ $? != 0 ]; then
  READELF=$(type dump 2> /dev/null)
  if [ $? != 0 ]; then
    echo Unable to find ELF reader
    exit 1
  fi
  READELF="dump -Lv"
else
  READELF="readelf -d"
fi
 
 
 
echo "Analyzing dependencies of: $INPUT"
echo "Creating output as:        $OUTPUT"
echo ""
 
echo "digraph DependencyTree {" > $TMPFILE
echo "  \"$(basename $INPUT)\" [shape=box];" >> $TMPFILE
analyze $TMPFILE "$INPUT"
echo "}" >> $TMPFILE
 #cat $TMPFILE # output generated dotfile for debugging purposses
dot -Tpng $TMPFILE -o$OUTPUT
 
rm $LDDTMPFILE
rm $TMPFILE
 exit 0