How to list library dependencies of a non-native b

Question

When developing for native platform, I can use ldd to list all the shared libraries (.so files) a binary executable I build will try to load upon start-up. But when cross-compiling, I don't know how to get the same information. The ldd is not a normal binutils utility, like strip or ar, that can be built alongside gcc for cross compiling, but instead, it is a cryptic shell script that apparently can only run on native platform.

So, using the cross-target binutils tools, is there any way to get a list of the dynamically linked dependency for of a foreign binary?

Answer 1

while in gdb, info shared is similar to ldd. It gives complete human readable runtime information of the executable.
readelf would miss path and other libraries information.
readelf is a very good tool for on the host study. Developer may choose that works.

Answer 2

some depends idiot just uploaded this. i'm sure it shows things LDD doesn't but it's not well tested yet. a small bit of output is shown below.

http://sourceforge.net/p/dep-trace/

http://sourceforge.net/projects/dep-trace/files/libdeps

should show total dependancy table of what ldconfig(1) will load (or has already loaded) and show which libs are NOT_FOUND (ie, no version or file) and then also what is effected.

try it, enjoy. it's very new so don't say i didn't tell you. it did just find some things below i didn't know about my lib system - i'm just about to go fix that.

# libdeps objdump -h
Experimental - see help
libdeps [objdump | ldd] [-l | file]
       -l  use find *.so is used on ldconfig dirs
     file  one file.so per line
snip...

# libdeps objdump -d

LIBTABLE

ld-linux.so.2(file)

ld-linux.so.2(GLIBC_2.0)(file)

ld-linux.so.2(GLIBC_2.1)(file)

ld-linux.so.2(GLIBC_2.0)(file)

ld-linux.so.2(GLIBC_2.3)(file)

ld-linux.so.2(GLIBC_2.1)(file)

ld-linux.so.2(GLIBC_PRIVATE)(file)

ld-linux.so.2(GLIBC_2.3)(file)

libBrokenLocale.so.1(file)

snip ...

libc.so.6 libc.so.6(file) ld-linux.so.2 ld-linux.so.2(GLIBC_2.0) ld-linux.so.2(GLIBC_2.1) ld-linux.so.2(GLIBC_PRIVATE)

snip ...

libanl.so.1 libanl.so.1(file) ld-linux.so.2 ld-linux.so.2(GLIBC_2.0) ld-linux.so.2(GLIBC_2.1) ld-linux.so.2(GLIBC_PRIVATE) libc.so.6(GLIBC_2.1.3) libc.so.6(GLIBC_2.0) libc.so.6 libc.so.6(GLIBC_2.1) libc.so.6(GLIBC_2.3) libc.so.6(GLIBC_2.2) libc.so.6(GLIBC_PRIVATE) libc.so.6(GLIBC_2.3.2) libc.so.6(GLIBC_2.1.2) libpthread.so.0(GLIBC_2.1) libpthread.so.0


libnss_db.so.2 libnss_db.so.2(file) ld-linux.so.2 ld-linux.so.2(GLIBC_2.0) ld-linux.so.2(GLIBC_2.1) ld-linux.so.2(GLIBC_PRIVATE) libc.so.6(GLIBC_2.1.3) libc.so.6(GLIBC_2.0) libc.so.6 libc.so.6(GLIBC_2.1) libc.so.6(GLIBC_2.3) libc.so.6(GLIBC_2.2) libc.so.6(GLIBC_PRIVATE) libnss_files.so.2 libnss_files.so.2(GLIBC_PRIVATE) libdb3.so.3(NOT_FOUND) libdb3.so.3(DB3_2)(NOT_FOUND)

snip...

NOT_FOUND
libctutils.so.0

libdb3.so.3

libdb3.so.3(DB3_2)

EFFECTED
libctutils.so.0 libconsole.so.0

libdb3.so.3 libnss_db.so.2

libdb3.so.3(DB3_2) libnss_db.so.2

libconsole.so.0

libnss_db.so.2

12/04/14  21:56  -0500     Thursday,  December  04,  2014,  09:56:35 PM  EST

Answer 3

A bit late for this addition but someone might benefit/clarify. Doesn't the -A flag to readelf give the same result as ldd?

    $ readelf -AW /bin/vi

Library list section '.gnu.liblist' contains 8 entries:
     Library              Time Stamp          Checksum   Version Flags
  0: libselinux.so.1      2011-07-25T08:02:58 0x17a7d5f7 0       0
  1: libtermcap.so.2      2011-07-25T08:02:59 0x29ae9ff7 0       0
  2: libacl.so.1          2011-07-25T08:02:58 0x60748842 0       0
  3: libc.so.6            2011-07-25T08:02:58 0x0c2c7eeb 0       0
  4: libdl.so.2           2011-07-25T08:02:58 0xdfbfc467 0       0
  5: libsepol.so.1        2011-07-25T08:02:58 0x857499cb 0       0
  6: /lib64/ld-linux-x86-64.so.2 2011-07-25T08:02:58 0x9e6549b7 0       0
  7: libattr.so.1         2011-07-25T08:02:58 0x862f1546 0       0

The only info missing here seems to be the full path where those libraries are located.

On the other hand, the tools mentioned so far are only useful once you have an installation known to work. My most common problems are:

1. Installing a program (mostly via rpm) that then fails to start or crashes during start up. Somehow I think this is related to library incompatibilities but I haven't found an easy way of checking these thing before installing a program (nor indeed after)
2. In an attemtp to overcome (1), sometimes I have resorted to downloading the sources and compiling locally. The typical configure script is partially helpful because it tells you which libraries you are missing. However, it fails to tell you what the lowest version of such libraries are required

Can anyone shed some light on these issues? BTW, I have tried reading installation instructions and release notes but they are almost always nowhere near sufficient.

A beefy example may put everything into context, so please try compiling Cinelerra.

Answer 4

Sorry to make a zombie thread, but I am working on some things for my OpenWRT router and wanted this to check some dependencies to see if I had enough space on my jffs2 partition to copy over just e2fsck. Short answer: nope.avi.

Anyhoo, I made a little script that uses the accepted answer plus some (probably overly verbose) grep calls and with a little hand waving and some unicorn tears (no worries, they were happy tears!) I managed to put together the following script that gives you all the dependencies. I'm sure there's lots of room for improvement especially RE: the loops and recursion, as well as the fact that it's all bashisms all the time (i.e. indexed arrays) but this is at least nominally working for me:

#!/bin/bash

declare -a search_path
declare -a found_deps

find_dependencies() {
    local file="$1"
    local -a deps
    local -a deps_to_process

    deps=( $( readelf -d "$file" | grep "NEEDED" | \
        grep -o -E "\[[^]]*\]" | grep -o -E "[^][]*" ) )

    local add_this_dep=true

    # always assume we've found $file and add it to the $found_deps list
    # if it's not there
    for found_dep in "${found_deps[@]}"
    do
        if [ "$found_dep" = "$(basename $file)" ]
        then
            add_this_dep=false
            break
        fi
    done

    # if $add_this_dep is true, go ahead and add to the found_deps list
    if $add_this_dep
    then
        found_deps+=("$(basename $file)")
    fi

    # for every dependency found by readelf (no path)
    for dep in "${deps[@]}"
    do
        local process_dep=true

        # if the basename of the file passed into the function is
        # this dep, skip processing altogether
        if [ "$dep" = "$(basename $file)" ]
        then
            break
        else
            # otherwise, if it's one of the 'found deps' don't process it
            for found_dep in "${found_deps[@]}"
            do
                if [ "$dep" = "$found_dep" ]
                then
                    process_dep=false
                    break
                fi
            done

            # it wasn't one of the 'found deps' so add 
            # it to the found_deps list
            if $process_dep
            then
                found_deps+=($dep)
            fi
        fi

        # if we are supposed to process this dep
        if $process_dep
        then
            local file_path=

            # check each search path for a file named $dep underneath it
            for dir in $search_path
            do
                file_path=$( find "$dir" -name "$dep" | head -n 1 )

                # if the $file_path is not empty, then we found
                # a copy of it, so break out of the loop
                if [ -n "$file_path" ]; then break; fi;
            done

            # if the $file_path is not empty, then we found a copy
            # of the file, place it the list of deps to be processed
            if [ -n "$file_path" ]
            then
                deps_to_process+=($file_path)
            fi
        fi
    done

    # now, go through all of our $deps_to_process (with path)
    # and run "find_dependencies" on them
    for dep_to_process in "${deps_to_process[@]}"
    do
        find_dependencies "$dep_to_process"
    done
}

argc=$#

if [ $argc -eq 0 ]
then
    printf '%s: prints dependencies of a (potentially) non-native elf executable, recursively\n'
    printf '\n'
    printf 'usage:\n'
    printf '\t%s <non-native elf executable> [ --supress-header ] [ <path> ... ]\n' "$(basename $0)"
    printf '\twhere\n'
    printf '\t\t<non-native elf executable> is the name of a file to find the dependencies of.\n'
    printf '\t\t[ <path> ... ] is an optional list of directories under which to search for libraries.\n'
    printf '\t\t[ --supress-header ] is an optional flag that prints nothing other than the list of files to stdout.\n'
    printf '\t\t\t(without the parameter a banner is sent to stderr)'
    printf '\n'
else
    file="$1"
    shift 1

    show_header=true

    if [ "$1" = "--supress-header" ]; then show_header=false; shift 1; fi;

    if $show_header
    then
        printf ' -------------------------------------------------------------------------------------------------------------\n' 1>&2
        printf '  ldd-nonnative: find all dependencies of a (potentially) non-native binary %s\n' "$file" 1>&2
        printf ' -------------------------------------------------------------------------------------------------------------\n' 1>&2
    fi

    search_path="$@"
    find_dependencies $file

    printf '\t%s\n' "${found_deps[@]}"
fi

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So, there ya go. Hope it helps someone. Egads it's taken me a long time to even get good enough with shell scripting to be able to pull something like this off, nevermind the fact that it took me much longer than it probably should have, so please forgive what has likely shaken some of you script gurus out there to the very core of your being. :)

Answer 5

is there any way to get a list of the dynamically linked dependency for of a foreign binary

You can list direct dependencies of a binary easily enough:

readelf -d a.out | grep NEEDED

 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]

I know of no way to recursively continue this to get the full list (as ldd does). You'll have to repeat the process for every NEEDED library by hand.

Answer 6

To list shared libraries dependency of a non-native binary, you can try the following tool: http://www.mathembedded.com/component/k2/item/1-cross-ldd.html

I use it on SH4 and MIPS. As reported in other answer, you can achieve the same using readelf output and a recursive loop, but I have never try by myself since cross-ldd exist.