features: add a directory-protection translator

This is useful to find all calls that remove a file from the protected
directory, including renames and internal calls.  Such calls will cause
a stack trace to be logged.  There's a filter script to add the needed
translators, and then the new functionality can be invoked with one of
the following commands.

	setfattr -n trusted.glusterfs.protect -v log $dir
	setfattr -n trusted.glusterfs.protect -v reject $dir
	setfattr -n trusted.glusterfs.protect -v anything_else $dir

The first logs calls, but still allows them.  The second rejects them
with EPERM.  The third turns off protection for that directory.

Change-Id: Iee4baaf8e837106be2b4099542cb7dcaae40428c
BUG: 888072
Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-on: http://review.gluster.org/4496
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 144 insertions, 0 deletions

diff --git a/extras/prot_filter.py b/extras/prot_filter.py
new file mode 100755
index 00000000..7dccacf1
--- /dev/null
+++ b/extras/prot_filter.py
@@ -0,0 +1,144 @@
+#!/usr/bin/python
+
+"""
+  Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+"""
+
+"""
+  INSTRUCTIONS
+  Put this in /usr/lib64/glusterfs/$version/filter to have it run automatically,
+  or else you'll have to run it by hand every time you change the volume
+  configuration.  Give it a list of volume names on which to enable the
+  protection functionality; it will deliberately ignore client volfiles for
+  other volumes, and all server volfiles.  It *will* include internal client
+  volfiles such as those used for NFS or rebalance/self-heal; this is a
+  deliberate choice so that it will catch deletions from those sources as well.
+"""
+
+volume_list = [ "jdtest" ]
+
+import copy
+import string
+import sys
+import types
+
+class Translator:
+    def __init__ (self, name):
+        self.name = name
+        self.xl_type = ""
+        self.opts = {}
+        self.subvols = []
+        self.dumped = False
+    def __repr__ (self):
+        return "<Translator %s>" % self.name
+
+def load (path):
+    # If it's a string, open it; otherwise, assume it's already a
+    # file-like object (most notably from urllib*).
+    if type(path) in types.StringTypes:
+        fp = file(path,"r")
+    else:
+        fp = path
+    all_xlators = {}
+    xlator = None
+    last_xlator = None
+    while True:
+        text = fp.readline()
+        if text == "":
+            break
+        text = text.split()
+        if not len(text):
+            continue
+        if text[0] == "volume":
+            if xlator:
+                raise RuntimeError, "nested volume definition"
+            xlator = Translator(text[1])
+            continue
+        if not xlator:
+            raise RuntimeError, "text outside volume definition"
+        if text[0] == "type":
+            xlator.xl_type = text[1]
+            continue
+        if text[0] == "option":
+            xlator.opts[text[1]] = string.join(text[2:])
+            continue
+        if text[0] == "subvolumes":
+            for sv in text[1:]:
+                xlator.subvols.append(all_xlators[sv])
+            continue
+        if text[0] == "end-volume":
+            all_xlators[xlator.name] = xlator
+            last_xlator = xlator
+            xlator = None
+            continue
+        raise RuntimeError, "unrecognized keyword %s" % text[0]
+    if xlator:
+        raise RuntimeError, "unclosed volume definition"
+    return all_xlators, last_xlator
+
+def generate (graph, last, stream=sys.stdout):
+    for sv in last.subvols:
+        if not sv.dumped:
+            generate(graph,sv,stream)
+            print >> stream, ""
+            sv.dumped = True
+    print >> stream, "volume %s" % last.name
+    print >> stream, "    type %s" % last.xl_type
+    for k, v in last.opts.iteritems():
+        print >> stream, "    option %s %s" % (k, v)
+    if last.subvols:
+        print >> stream, "    subvolumes %s" % string.join(
+            [ sv.name for sv in last.subvols ])
+    print >> stream, "end-volume"
+
+def push_filter (graph, old_xl, filt_type, opts={}):
+    new_type = "-" + filt_type.split("/")[1]
+    old_type = "-" + old_xl.xl_type.split("/")[1]
+    pos = old_xl.name.find(old_type)
+    if pos >= 0:
+        new_name = old_xl.name
+        old_name = new_name[:pos] + new_type + new_name[len(old_type)+pos:]
+    else:
+        new_name = old_xl.name + old_type
+        old_name = old_xl.name + new_type
+    new_xl = Translator(new_name)
+    new_xl.xl_type = old_xl.xl_type
+    new_xl.opts = old_xl.opts
+    new_xl.subvols = old_xl.subvols
+    graph[new_xl.name] = new_xl
+    old_xl.name = old_name
+    old_xl.xl_type = filt_type
+    old_xl.opts = opts
+    old_xl.subvols = [new_xl]
+    graph[old_xl.name] = old_xl
+
+if __name__ == "__main__":
+    path = sys.argv[1]
+    # Alow an override for debugging.
+    for extra in sys.argv[2:]:
+        volume_list.append(extra)
+    graph, last = load(path)
+    for v in volume_list:
+        if graph.has_key(v):
+            break
+    else:
+        print "No configured volumes found - aborting."
+        sys.exit(0)
+    for v in graph.values():
+        if v.xl_type == "cluster/distribute":
+            push_filter(graph,v,"features/prot_dht")
+        elif v.xl_type == "protocol/client":
+            push_filter(graph,v,"features/prot_client")
+    # We push debug/trace so that every fop gets a real frame, because DHT
+    # gets confused if STACK_WIND_TAIL causes certain fops to be invoked
+    # from anything other than a direct child.
+    for v in graph.values():
+        if v.xl_type == "features/prot_client":
+            push_filter(graph,v,"debug/trace")
+    generate(graph,last,stream=open(path,"w"))