horrendous hack to stubify a library

We dump the library's symbols we're trying to stubify, and then
assemble another library that looks just like it, except with all
of it's innards sucked out.
We also use pkgconfig to find all the relevant dependencies and
to build an entire library tree.

1 files changed, 262 insertions, 0 deletions

diff --git a/bin/stubify.pl b/bin/stubify.pl
new file mode 100755
index 000000000000..3564800b2f85
--- /dev/null
+++ b/bin/stubify.pl
@@ -0,0 +1,262 @@
+#!/usr/bin/env perl
+
+use Fcntl;
+use POSIX;
+use strict;
+
+# simple pkgconfig goodness
+my $destdir;
+my $recursive = 0;
+my $assembler_out = 0;
+my %pkg_configs = ();
+my @pkg_config_paths = split(/:/, $ENV{PKG_CONFIG_PATH});
+push @pkg_config_paths, "/usr";
+
+# Stubify a shared library ...
+sub read_gen_symbols($$)
+{
+    my ($shlib, $fh) = @_;
+    my $obj;
+
+    print $fh "\t.file \"$shlib\"\n";
+    open $obj, "objdump -T $shlib|" || die "Can't objdump $shlib: $!";
+
+    while (my $line = <$obj>) {
+	$line =~ /([0-9a-f]*)\s+([gw ])\s+..\s+(\S*)\s*([0-9a-f]+)..............(.*)/ || next;
+	my ($address, $linkage, $type, $size, $symbol) = ($1, $2, $3, $4, $5);
+
+	next if ($type eq '*UND*' || $type eq '*ABS*');
+
+#	print "Symbol '$symbol' type '$type' '$linkage' addr $address, size $size\n";
+
+	$symbol || die "no symbol for line $line";
+
+	next if ($symbol eq '_init' || $symbol eq '_fini');
+
+	$linkage =~ s/g//g;
+
+	my $progbits = '@progbits';
+	$progbits = '@nobits' if ($type eq '.bss');
+	print $fh "\t.section $type.$symbol,\"a".$linkage."G\",$progbits,$symbol,comdat\n";
+	print $fh ".globl $symbol\n";
+	print $fh "\t.type $symbol,";
+	if ($type eq '.text') {
+	    print $fh "\@function\n";
+	} else {
+	    print $fh "\@object\n";
+	}
+	print $fh "$symbol:\n";
+	if ($type eq '.text') {
+	    print $fh "\tret\n";
+	} else {
+	    my $isize = hex($size);
+	    print $fh "\t.size $symbol, $isize\n";
+	    for (my $i = 0; $i < $isize; $i++) {
+		print $fh "\t.byte 0\n";
+	    }
+	}
+	print $fh "\n";
+    }
+
+    close $obj;
+}
+
+sub stubify($$)
+{
+    my $shlib = shift;
+    my $output = shift;
+    my ($pipe, $tmpf);
+
+    my $tmpname;
+    do {
+	$tmpname = tmpnam();
+    } until sysopen($tmpf, $tmpname, O_RDWR|O_CREAT|O_EXCL, 0666);
+    close($tmpf);
+
+    if ($assembler_out) {
+	open ($pipe, ">-");
+    } else {
+	open ($pipe, "| as -o $tmpname") || die "can't start assembler: $!";
+    }
+    read_gen_symbols ($shlib, $pipe);
+    close ($pipe) || die "Failed to assemble to: $tmpname: $!";
+
+    system ("gcc -shared -o $output $tmpname") && die "failed to exec gcc: $!";
+    unlink $tmpname;
+}
+
+sub help_exit()
+{
+    print "Usage: stubify <destdir> <pkg-config-names>\n";
+    print "Converts libraries into stubs, and bundles them and their pkg-config files\n";
+    print "into destdir\n";
+    print "  -R        stubbify and include all dependent pkgconfig files\n";
+    exit 1;
+}
+
+sub parse_pkgconfig($$)
+{
+    my $name = shift;
+    my $file = shift;
+    my $fh;
+    my %hash;
+    my @hashes;
+
+    print "parse $file\n";
+    open ($fh, $file) || die "Can't open $file: $!";
+    while (<$fh>) {
+	my ($key, $value);
+	if (/^\s*([^=]+)\s*=\s*([^=]+)\s*$/) {
+	    $key = $1; $value = $2;
+	} elsif (/^\s*([^:]+)\s*:\s*([^:]+)\s*$/) {
+	    $key = $1; $value = $2;
+	} elsif (/^\s*$/) {
+	    next;
+	} else {
+	    die "invalid pkgconfig line: $_\n";
+	}
+	chomp ($key); chomp ($value);
+	$hash{$key} = $value;
+    }
+    close ($fh);
+    for my $key (keys (%hash)) {
+	print "\t'$key'\t=\t'$hash{$key}'\n";
+    }
+
+    $hash{_Name} = $name;
+    $hash{_File} = $file;
+
+    push @hashes, \%hash;
+    if ($recursive &&
+	!defined $pkg_configs{$name} &&
+	defined $hash{Requires}) {
+	my @reqs = ();
+	for my $req (split (/[ ,]/, $hash{Requires})) {
+	    print "parse $req of $name\n";
+	    push @reqs, get_pc_files($req);
+	}
+	$hash{_Requires} = \@reqs;
+	push @hashes, @reqs;
+    }
+    $pkg_configs{$name} = \%hash;
+    return @hashes;
+}
+
+sub get_pc_files($)
+{
+    my $name = shift;
+    for my $prefix (@pkg_config_paths) {
+	my $path = "$prefix/lib/pkgconfig/$name.pc";
+	return parse_pkgconfig ($name,$path) if (-f $path);
+    }
+    die "Failed to find pkg-config file for $name";
+}
+
+# primitive substitution
+sub get_var($$)
+{
+    my ($pc, $var) = @_;
+    my $val = $pc->{"$var"};
+    while ($val =~ m/^(.*)\$\{\s*(\S+)\s*\}(.*)$/) {
+	$val = $1 . get_var($pc, $2). $3;
+    }
+    return $val;
+}
+
+sub copy_lib($@)
+{
+    my $lib = shift;
+    while (my $path = shift) {
+	my $name = "$path/$lib";
+	next if (! -f $name);
+
+	# need to run ldconfig post install ...
+	while (-l $name) {
+	    my $dir = $name;
+	    $dir =~ s/\/[^\/]*$//;
+	    my $link = readlink($name);
+	    if ($link =~ m/^\//) {
+		$name = $link;
+	    } else {
+		$name = "$dir/$link";
+	    }
+	}
+
+	# ignore /lib - they use monstrous symbol versioning
+	if ($name =~ m/^\/lib/) {
+	    print "\tskipping system library: $lib in $name\n";
+	    return;
+	}
+
+	stubify ($name, "$destdir/$name");
+    }
+}
+
+sub copy_and_stubify ($)
+{
+    my $pc = shift;
+
+    `mkdir -p $destdir/lib/pkgconfig`;
+    `mkdir -p $destdir/$pc->{libdir}` if (defined $pc->{libdir});
+    `mkdir -p $destdir/$pc->{includedir}` if (defined $pc->{includedir});
+
+    # copy .pc across - FIXME, may need to re-write paths
+    `cp -a $pc->{_File} $destdir/lib/pkgconfig`;
+
+    # copy includes across
+    my @includes = split (/ /, get_var ($pc, "Cflags"));
+    for my $arg (@includes) {
+	if ($arg =~ m/^-I(.*)$/) {
+	    my $srcdir = $1;
+	    if (! -d $srcdir || $srcdir eq '/usr/include') {
+		print "Warning: bogus include of '$srcdir' for pkg $pc->{_Name}\n";
+	    } else {
+		`mkdir -p $destdir/$srcdir`;
+		`cp -a $srcdir/* $destdir/$srcdir`;
+	    }
+	}
+    }
+
+    # stubify libraries
+    my @libs = split (/ /, get_var ($pc, "Libs"));
+    my @libpath = ( "/lib", "/usr/lib" );
+    for my $arg (@libs) {
+	if ($arg =~ m/^-l(.*)$/) {
+	    my $lib = "lib".$1.".so";
+#	    print "lib $lib @libpath?\n";
+	    copy_lib ($lib, @libpath);
+	} elsif ($arg =~ m/^-L(.*)$/) {
+	    my $path = $1;
+	    push (@libpath, $path) if (! grep ($path, @libpath));
+	}
+    }
+}
+
+my @pcnames = ();
+my @tostub;
+
+for my $arg (@ARGV) {
+    if ($arg eq '--help' || $arg eq '-h') {
+	help_exit();
+    } elsif ($arg eq '-r' || $arg eq '-R') {
+	$recursive = 1;
+    } elsif (!defined $destdir) {
+	$destdir = $arg;
+    } else {
+	push @pcnames, $arg;
+    }
+}
+
+help_exit() if (!defined $destdir);
+`mkdir -p $destdir`;
+
+for my $name (@pcnames) {
+    push @tostub, get_pc_files($name);
+}
+print "stubify: ";
+select STDERR; $| = 1;
+for my $pc (@tostub) {
+    print " " . $pc->{_Name} . "\n";
+    copy_and_stubify ($pc);
+}
+print "\n";