source: vendor/perl/5.8.8/Porting/findrfuncs

#!/usr/bin/perl -ws

#
# findrfuncs: find reentrant variants of functions used in an executable.
#
# Requires a functional "nm -u".  Searches headers in /usr/include
# to find available *_r functions and looks for non-reentrant
# variants used in the supplied executable.
#
# Requires debug info in the shared libraries/executables.
#
# Gurusamy Sarathy
# gsar@ActiveState.com
#
# Hacked to automatically find the executable and shared objects.
# --jhi

use strict;
use File::Find;

my @EXES;
my $NMU = 'nm -u';
my @INCDIRS = qw(/usr/include);
my $SO = 'so';
my $EXE = '';

if (open(CONFIG, "config.sh")) {
    local $/;
    my $CONFIG = <CONFIG>;
    $SO  = $1 if $CONFIG =~ /^so='(\w+)'/m;
    $EXE = $1 if $CONFIG =~ /^_exe='\.(\w+)'/m;
    close(CONFIG);
}

push @EXES, "perl$EXE";

find(sub {push @EXES, $File::Find::name if /\.$SO$/}, '.' );

push @EXES, @ARGV;

if ($^O eq 'dec_osf') {
    $NMU = 'nm -Bu';
} elsif ($^O eq 'irix') {
    $NMU = 'nm -pu';
}

my %rfuncs;
my @syms;
find(sub {
        return unless -f $File::Find::name;
        local *F;
        open F, "<$File::Find::name"
            or die "Can't open $File::Find::name: $!";
        my $line;
        while (defined ($line = <F>)) {
            if ($line =~ /\b(\w+_r)\b/) {
                #warn "$1 => $File::Find::name\n";
                $rfuncs{$1}->{$File::Find::name}++;
            }
        }
        close F;
     }, @INCDIRS);

# delete bogus symbols grepped out of comments and such
delete $rfuncs{setlocale_r} if $^O eq 'linux';

# delete obsolete (as promised by man pages) symbols
my $netdb_r_obsolete;
if ($^O eq 'hpux') {
    delete $rfuncs{crypt_r};
    delete $rfuncs{drand48_r};
    delete $rfuncs{endgrent_r};
    delete $rfuncs{endpwent_r};
    delete $rfuncs{getgrent_r};
    delete $rfuncs{getpwent_r};
    delete $rfuncs{setlocale_r};
    delete $rfuncs{srand48_r};
    delete $rfuncs{strerror_r};
    $netdb_r_obsolete = 1;
} elsif ($^O eq 'dec_osf') {
    delete $rfuncs{crypt_r};
    delete $rfuncs{strerror_r};
    $netdb_r_obsolete = 1;
}
if ($netdb_r_obsolete) {
    delete @rfuncs{qw(endhostent_r
                      endnetent_r
                      endprotoent_r
                      endservent_r
                      gethostbyaddr_r
                      gethostbyname_r
                      gethostent_r
                      getnetbyaddr_r
                      getnetbyname_r
                      getnetent_r
                      getprotobyname_r
                      getprotobynumber_r
                      getprotoent_r
                      getservbyname_r
                      getservbyport_r
                      getservent_r
                      sethostent_r
                      setnetent_r
                      setprotoent_r
                      setservent_r)};
}

my %syms;

for my $exe (@EXES) {
    # warn "#--- $exe\n";
    for my $sym (`$NMU $exe 2>/dev/null`) {
        chomp $sym;
        $sym =~ s/^\s+//;
        $sym =~ s/^([0-9A-Fa-f]+\s+)?[Uu]\s+//;
        $sym =~ s/\s+[Uu]\s+-$//;
        next if $sym =~ /\s/;
        $sym =~ s/\@.*\z//;     # remove @@GLIBC_2.0 etc
        # warn "#### $sym\n";
        if (exists $rfuncs{"${sym}_r"} && ! $syms{"$sym:$exe"}++) {
            push @syms, $sym;
        }
    }
    
    if (@syms) {
        print "\nFollowing symbols in $exe have reentrant versions:\n";
        for my $sym (@syms) {
            my @f = sort keys %{$rfuncs{$sym . '_r'}};
            print "$sym => $sym" . "_r (@f)\n";
        }
    }
    @syms = ();
}