findinsharedlibs

#!/usr/bin/env perl
use strict;
use warnings;
use Getopt::Long;
use Pod::Usage;
use Env;

my @dirs = ();
my $help = 0;

GetOptions("help|?" => \$help) or pod2usage(2);
pod2usage(-exitval => 0, -verbose => 2) if $help;

die "findinsharedlibs must have a function to search for" if (@ARGV < 1);
@dirs = split(/:/,$ENV{'LD_LIBRARY_PATH'}) if defined($ENV{'LD_LIBRARY_PATH'});

foreach my $line (`ldconfig -v 2> /dev/null`) {
  push @dirs,(split /:/, $line)[0] if ($line =~ /^\//);
}

foreach my $thisDir (@dirs) { # iterate through LD_LIBRARY_PATH & ld.conf
  chdir $thisDir;
  foreach my $file (glob("*.a *.so")) {
    my @list = grep(/$ARGV[0]/,`nm --defined-only -g $file 2> /dev/null`);
    print $thisDir . "/" . $file,"\n" if (@list > 0);
  }
}

__END__

=head1 NAME

findinsharedlibs - find a routine in the list of possible shared libraries

=head1 SYNOPSIS

findinsharedlibs name_of_routine_to_find

=head1 DESCRIPTION

This short perl script that finds the library where the specified library
is defined. I have hit this case multiple times, trying to port a piece
of Linux code where a specific routine comes up as unresolved and I have
to grep through all the standard library locations, /lib, /usr/lib, etc.
looking for some library that defines that routine. I have not found a
general Linux command to let me do this. This routine searches all the
library pathes defined by ld.conf and LD_LIBRARY_PATH if defined.

For example, I want to know where where the sysfs_ functions are defined.
This was the specific case that caused me to write this:

edt @ centosi.ed-thompson.org ! /home/edt $ findinsharedlibs sysfs_
/usr/lib/libdmraid.a
/usr/lib/libibverbs.a
/usr/lib/liblvm2cmd.a
/usr/lib/libsysfs.a

=cut

Nice!