Copying Shared Library Dependencies

I call it cpld a simple utility for copying shared library dependencies to a given folder

Shared library dependenices can be easily listed with the help of ldd– list dynamic dependencies of executable files or shared objects.

Clues in the ldd source:

ldd is a very simple utility, that prints the shared libraries required by each program or shared library specified on the command line.

In the ldd source code, there is a line with a comment /ld.so magic /

setenv("LD_TRACE_LOADED_OBJECTS", "yes", 1);

Lets see an example:

$ LD_TRACE_LOADED_OBJECTS=1 /bin/bash
    linux-vdso.so.1 =>  (0x00007fff11bff000)
    libncurses.so.5 => /lib/libncurses.so.5 (0x00007f8bfcab0000)
    libdl.so.2 => /lib/libdl.so.2 (0x00007f8bfc8ac000)
    libc.so.6 => /lib/libc.so.6 (0x00007f8bfc529000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f8bfccf3000)
$ ldd /bin/bash
    linux-vdso.so.1 =>  (0x00007fffe1dff000)
    libncurses.so.5 => /lib/libncurses.so.5 (0x00007fc92daf3000)
    libdl.so.2 => /lib/libdl.so.2 (0x00007fc92d8ef000)
    libc.so.6 => /lib/libc.so.6 (0x00007fc92d56b000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fc92dd5a000)

So, the outputs are the same, indeed ldd uses /lib/ld.so with LD_TRACE_LOADED_OBJECTS evn set.

When working will virtual environment for an evalbot there was repeated use of ldd and fixing binaries, so this made me to write a small utility to do the job easy, the code is as below:

#!/bin/bash 
# Author : Hemanth.HM
# Email : hemanth[dot]hm[at]gmail[dot]com
# License : GNU GPLv3
#

function useage()
{
    cat << EOU
Useage: bash $0 <path to the binary> <path to copy the dependencies>
EOU
exit 1
}

#Validate the inputs
[[ $# < 2 ]] && useage

#Check if the paths are vaild
[[ ! -e $1 ]] && echo "Not a vaild input $1" && exit 1 
[[ -d $2 ]] || echo "No such directory $2 creating..."&& mkdir -p "$2"

#Get the library dependencies
echo "Collecting the shared library dependencies for $1..."
deps=$(ldd $1 | awk 'BEGIN{ORS=" "}$1\
~/^\//{print $1}$3~/^\//{print $3}'\
 | sed 's/,$/\n/')
echo "Copying the dependencies to $2"

#Copy the deps
for dep in $deps
do
    echo "Copying $dep to $2"
    cp "$dep" "$2"
done

echo "Done!"

Case studies :

$ bash cpld.bash 
Useage: bash cpld.bash <path to the binary> <path to copy the dependencies>

$ bash cpld.bash /bin/bash
Useage: bash cpld.bash <path to the binary> <path to copy the dependencies>

$ bash cpld.bash /tmp/tet /tmp/test
Not a vaild input /tmp/tet

$ bash cpld.bash /bin/bash /tmp/deps
No such directory /tmp/deps creating...
Collecting the shared library dependencies for /bin/bash...
Copying the dependencies to /tmp/deps
Copying /lib/libncurses.so.5 to /tmp/deps
Copying /lib/libdl.so.2 to /tmp/deps
Copying /lib/libc.so.6 to /tmp/deps
Copying /lib64/ld-linux-x86-64.so.2 to /tmp/deps
Done!

Get the code