source: bootcd/isolinux/syslinux-6.03/com32/lib/makeerrlist.pl

#!/usr/bin/perl
#
# This creates sys_errlist from <asm/errno.h> through somewhat
# heuristic matching.  It presumes the relevant entries are of the form
# #define Exxxx <integer> /* comment */
#

use FileHandle;

%errors  = ();
%errmsg  = ();
$maxerr  = -1;
@includelist = ();              # Include directories

sub parse_file($) {
    my($file) = @_;
    my($fh) = new FileHandle;
    my($line, $error, $msg);
    my($kernelonly) = 0;
    my($root);

    print STDERR "opening $file\n" unless ( $quiet );

    $ok = 0;
    foreach $root ( @includelist ) {
        if ( $fh->open($root.'//'.$file, '<') ) {
            $ok = 1;
            last;
        }
    }

    if ( ! $ok ) {
        die "$0: Cannot find file $file\n";
    }

    while ( defined($line = <$fh>) ) {
        if ( $kernelonly ) {
            if ( $line =~ /^\#\s*endif/ ) {
                $kernelonly--;
            } elsif ( $line =~ /^\#\sif/ ) {
                $kernelonly++;
            }
        } else {
            if ( $line =~ /^\#\s*define\s+([A-Z0-9_]+)\s+([0-9]+)\s*\/\*\s*(.*\S)\s*\*\// ) {
                $error = $1;
                $errno = $2+0;
                $msg   = $3;
                print STDERR "$error ($errno) => \"$msg\"\n" unless ( $quiet );
                $errors{$errno} = $error;
                $errmsg{$errno} = $msg;
                $maxerr = $errno if ( $errno > $maxerr );
            } elsif ( $line =~ /^\#\s*include\s+[\<\"](.*)[\>\"]/ ) {
                parse_file($1);
            } elsif ( $line =~ /^\#\s*ifdef\s+__KERNEL__/ ) {
                $kernelonly++;
            }
        }
    }
    close($fh);
    print STDERR "closing $file\n" unless ( $quiet );
}

$v = $ENV{'KBUILD_VERBOSE'};
$quiet = defined($v) ? !$v : 0;

foreach $arg ( @ARGV ) {
    if ( $arg eq '-q' ) {
        $quiet = 1;
    } elsif ( $arg =~ /^-(errlist|errnos|maxerr)$/ ) {
        $type = $arg;
    } elsif ( $arg =~ '^\-I' ) {
        push(@includelist, "$'");
    } else {
        # Ignore
    }
}

parse_file('errno.h');

if ( $type eq '-errlist' ) {
    print  "#include <errno.h>\n";
    printf "const int sys_nerr = %d;\n", $maxerr+1;
    printf "const char * const sys_errlist[%d] = {\n", $maxerr+1;
    foreach $e ( sort(keys(%errors)) ) {
        printf "  [%s] = \"%s\",\n", $errors{$e}, $errmsg{$e};
    }
    print "};\n";
} elsif ( $type eq '-errnos' ) {
    print  "#include <errno.h>\n";
    printf "const int sys_nerr = %d;\n", $maxerr+1;
    printf "const char * const sys_errlist[%d] = {\n", $maxerr+1;
    foreach $e ( sort(keys(%errors)) ) {
        printf "  [%s] = \"%s\",\n", $errors{$e}, $errors{$e};
    }
    print "};\n";
} elsif ( $type eq '-maxerr' ) {
    print $maxerr, "\n";
}