Find all executable files that depend on the specified library in the specified directory

Question

My goal is to write a shell script that uses "objdump -p" command to find all executable files that depend on the specified library in the specified directory. (OpenBSD). I try something like this:

find $1 -perm -111 -print0 | xargs -r0 objdump -p | grep -l "NEEDED      $2"

But this solution doesn't work because grep cannot figure out the filenames in which it found the given match. The difficulty is to determine the names of the executable files in which grep found the specified library. Can anyone suggest a solution using the "objdump -p" command?

Answer 1

The trick is to execute a shell script rather than a single command to be able to re-use the file name.

finddepend() {
# Arg 1: The directory where to find
# Arg 2: The library name
  basedir=$1
  libname=$2
  find "$basedir" \
    \( -perm -100 -o -perm -010 -o -perm -001 \) \
    \( -type f -o -type l \) \
    -exec sh -c '
# Arg 0: Is a dummy _ for this inline script
# Arg 1: The executable file path
# Arg 2: The library name
filepath=$1
libname=$2
objdump -p "$filepath" 2>/dev/null |
  if grep -qF "  NEEDED               $libname"; then
    printf %s\\n "${filepath##*/}"
  fi
' _ {} "$libname" \;
}

Example usage:

finddepend /bin libselinux.so
mv
systemctl
tar
sed
udevadm
ls
mknod
systemd
mkdir
ss
dir
vdir
cp
systemd-hwdb
netstat

Answer 2

Why do you want to use objdump when you can use ldd (List Dynamic Dependencies)? objdump gives a complete summary, which you need to process in order only to get the information you're looking for, while ldd only gives you that information.