Re: Stripped kernel modules?

Aaron M. Ucko (amu@mit.edu)
20 May 1998 13:20:51 -0500

Nitpickish patch, mostly to address my dislike of easily avoided
single-argument calls to system (multi-argument calls being safer and
more efficient):

--- selstrip.pl.dist Wed May 20 12:59:39 1998
+++ selstrip.pl Wed May 20 13:11:19 1998
@@ -26,6 +26,7 @@
require 5;
use strict;
use English;
+use POSIX;

my $strip = "/usr/bin/strip";
my $nm = "/usr/bin/nm";
@@ -33,10 +34,10 @@
my $mv = "/bin/mv";
my $rm = "/bin/rm";
my $tmp = "/tmp";
-my $command_size = 400; # arbitrary but safe

my $tmpcopy = "$tmp/$PID.object";
-my $nmout = "$tmp/$PID.nmout";
+
+my $command_size = sysconf(&_SC_ARG_MAX) - length("$strip $tmpcopy ");

my $i;

@@ -44,17 +45,18 @@
strip_module($ARGV[$i]);
}

-do_command("$rm -f $tmpcopy $nmout");
+# do_command($rm, '-f', $tmpcopy, $nmout);
+unlink $tmpcopy or die "unlink failed: $ERRNO";

exit(0);

sub strip_module()
{
my ($object) = @_;
- my (%keep, %to_strip, $symbol, $command, $changed, $line, @f);
- do_command("$cp -a $object $tmpcopy");
- do_command("$nm $tmpcopy > $nmout");
- open(NMOUT, "<$nmout") || die "cannot read $nmout";
+ my (%keep, %to_strip, $symbol, @command, $cmdlen, $changed, $line);
+ my (@f, $s);
+ do_command($cp, '-a', $object, $tmpcopy);
+ open(NMOUT, "$nm $tmpcopy|") || die "nm failed: $ERRNO";
while (defined($line = <NMOUT>)) {
chop($line);
my @field = split(' ', substr($line, 9));
@@ -95,32 +97,36 @@
}
}
close(NMOUT);
- $command = "";
+ @command = ();
+ $cmdlen = 0;
$changed = 0;
foreach $symbol (keys(%to_strip)) {
if (!defined($keep{$symbol})) {
$changed = 1;
- if (length($command) > $command_size) {
- do_command("$strip $command $tmpcopy");
- $command = "";
+ $s = "--strip-symbol=$symbol";
+ if ($cmdlen + length($s) >= $command_size) {
+ do_command($strip, @command, $tmpcopy);
+ @command = ();
+ $cmdlen = 0;
}
- $command = "$command --strip-symbol=$symbol";
+ push(@command, $s);
+ $cmdlen += length("$s ");
}
}
- if ($command ne "") {
+ if (@command) {
$changed = 1;
- do_command("$strip $command $tmpcopy");
+ do_command($strip, @command, $tmpcopy);
}
if ($changed) {
- do_command("$mv $tmpcopy $object");
+ do_command($mv, $tmpcopy, $object);
}
}

sub do_command()
{
- my ($command) = @_;
+ my @command = @_;
my $ret;
- if (($ret = system($command)) != 0) {
- die("command \"$command\" failed $ret");
+ if (($ret = system(@command)) != 0) {
+ die('command "', join(' ', @command), "\" failed ($ret)");
}
}

-- 
Aaron M. Ucko <amu@mit.edu> (finger amu@monk.mit.edu) [Stark raving sane]


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