src: rewrite symfile library checker in Python

As part of a goal to eliminate Perl from libvirt build tools,
rewrite the check-symfile.pl tool in Python.

This was a straight conversion, manually going line-by-line to
change the syntax from Perl to Python. Thus the overall structure
of the file and approach is the same.

Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Makefile.am

@@ -48,6 +48,7 @@ EXTRA_DIST = \
   scripts/augeas-gentest.py \
   build-aux/check-spacing.pl \
   scripts/check-aclperms.py \
+  scripts/check-symfile.py \
   scripts/check-symsorting.py \
   scripts/header-ifdef.py \
   scripts/minimize-po.py \

scripts/check-symfile.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2012-2019 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+from __future__ import print_function
+
+import re
+import subprocess
+import sys
+
+if len(sys.argv) < 3:
+    print("syntax: %s SYMFILE ELFLIB(S)" % sys.argv[0], file=sys.stderr)
+
+symfile = sys.argv[1]
+elflibs = sys.argv[2:]
+
+wantsyms = {}
+gotsyms = {}
+
+ret = 0
+
+with open(symfile, "r") as fh:
+    for line in fh:
+        line = line.strip()
+        if line.find("{") != -1:
+            continue
+        if line.find("}") != -1:
+            continue
+        if line in ["global:", "local:"]:
+            continue
+        if line == "":
+            continue
+        if line[0] == '#':
+            continue
+        if line.find("*") != -1:
+            continue
+
+        line = line.strip(";")
+
+        if line in wantsyms:
+            print("Symbol $1 is listed twice", file=sys.stderr)
+            ret = 1
+        else:
+            wantsyms[line] = True
+
+for elflib in elflibs:
+    nm = subprocess.Popen(["nm", elflib], shell=False,
+                          stdout=subprocess.PIPE).stdout
+
+    for line in nm:
+        line = line.decode("utf-8")
+        symmatch = re.search(r'''^\S+\s(?:[TBD])\s(\S+)\s*$''', line)
+        if symmatch is None:
+            continue
+
+        gotsyms[symmatch.group(1)] = True
+
+
+for sym in wantsyms.keys():
+    if sym in gotsyms:
+        continue
+
+    print("Expected symbol '%s' is not in ELF library" % sym, file=sys.stderr)
+    ret = 1
+
+sys.exit(ret)

src/Makefile.am

@@ -277,15 +277,14 @@ PDWTAGS = \
 # rule for libvirt.la.  However, checking symbols relies on Linux ELF layout
 if WITH_LINUX
 check-symfile: libvirt.syms libvirt.la
-	$(AM_V_GEN)$(PERL) $(srcdir)/check-symfile.pl libvirt.syms \
-	  .libs/libvirt.so
+	$(AM_V_GEN)$(RUNUTF8) $(PYTHON) $(top_srcdir)/scripts/check-symfile.py \
+		libvirt.syms .libs/libvirt.so
 else ! WITH_LINUX
 check-symfile:
 endif ! WITH_LINUX
 check-symsorting:
 	$(AM_V_GEN)$(RUNUTF8) $(PYTHON) $(top_srcdir)/scripts/check-symsorting.py \
 		$(srcdir) $(SYM_FILES)
-EXTRA_DIST += check-symfile.pl
 
 # Keep this list synced with RPC_PROBE_FILES
 PROTOCOL_STRUCTS = \

src/admin/Makefile.inc.am

@@ -105,8 +105,8 @@ libvirt_admin_la_CFLAGS = \
 
 if WITH_LINUX
 check-admin-symfile: admin/libvirt_admin.syms libvirt-admin.la
-	$(AM_V_GEN)$(PERL) $(srcdir)/check-symfile.pl admin/libvirt_admin.syms \
-		.libs/libvirt-admin.so
+	$(AM_V_GEN)$(RUNUTF8) $(PYTHON) $(top_srcdir)/scripts/check-symfile.py \
+		admin/libvirt_admin.syms .libs/libvirt-admin.so
 else ! WITH_LINUX
 check-admin-symfile:
 endif ! WITH_LINUX

src/check-symfile.pl

@@ -1,70 +0,0 @@
-#!/usr/bin/env perl
-
-# Copyright (C) 2012-2013 Red Hat, Inc.
-#
-# This library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Lesser General Public
-# License as published by the Free Software Foundation; either
-# version 2.1 of the License, or (at your option) any later version.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# Lesser General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public
-# License along with this library.  If not, see
-# <http://www.gnu.org/licenses/>.
-
-die "syntax: $0 SYMFILE ELFLIB(S)" unless int(@ARGV) >= 2;
-
-my $symfile = shift @ARGV;
-my @elflibs = @ARGV;
-
-my %wantsyms;
-my %gotsyms;
-
-my $ret = 0;
-
-open SYMFILE, $symfile or die "cannot read $symfile: $!";
-
-while (<SYMFILE>) {
-    next if /{/;
-    next if /}/;
-    next if /global:/;
-    next if /local:/;
-    next if /^\s*$/;
-    next if /^\s*#/;
-    next if /\*/;
-
-    die "malformed line $_" unless /^\s*(\S+);$/;
-
-    if (exists $wantsyms{$1}) {
-        print STDERR "Symbol $1 is listed twice\n";
-        $ret = 1;
-    } else {
-        $wantsyms{$1} = 1;
-    }
-}
-close SYMFILE;
-
-foreach my $elflib (@elflibs) {
-    open NM, "-|", "nm", $elflib or die "cannot run 'nm $elflib': $!";
-
-    while (<NM>) {
-        next unless /^\S+\s(?:[TBD])\s(\S+)\s*$/;
-
-        $gotsyms{$1} = 1;
-    }
-
-    close NM;
-}
-
-foreach my $sym (keys(%wantsyms)) {
-    next if exists $gotsyms{$sym};
-
-    print STDERR "Expected symbol $sym is not in ELF library\n";
-    $ret = 1;
-}
-
-exit($ret);