[PATCH v2] coccinelle: add pycocci wrapper for multithreaded support

[Luis R. Rodriguez]

From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>

This is a wrapper for folks which by work on git trees, specifically
the linux kernel with lots of files and with random task Cocci files.
The assumption is all you need is multithreaded support and currently only
a shell script is lying around, but that isn't easily extensible, nor
is it dynamic. This uses Python to add Coccinelle's mechanisms for
multithreaded support but also enables all sorts of defaults which
you'd expect to be enabled when using Coccinelle for Linux kernel
development.

The Linux kernel backports project makes use of this tool on a daily
basis and as such you can expect more tuning to it. All this is being
done as Coccinelle's multithreaded support is being revamped but
that will take a while so we want something easy to use that is
extensible in the meantime.

The purpose of putting this into Coccinelle is to make the tool generic
and usable outside of backports. If this tool gets merged into
Coccinelle we'll just drop this copy and help evolve it within
Coccinelle.

You just pass it a cocci file, a target dir, and that's it.

Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
Cc: backports@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: cocci@xxxxxxxxxxxxxxx
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
---

This v2 has taken quite a bit of consideration into some additional flags
to make default, in particular --coccigrep is now used which proved in
the general case to not require increasing the number of threads depending
on the type of Cocci patch you produce. This patch also now puts pycocci
under tool tools/ directory. If I get an ACK I can commit and push.

If you'd like to downlaod this tool I'll try to keep an updated version
here:

http://drvbp1.linux-foundation.org/~mcgrof/coccinelle/

Its also currently available under the backports project -- until and only
if Coccinelle does wish to carry this internally in its own repo / releases.

 tools/pycocci | 180 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 180 insertions(+)
 create mode 100755 tools/pycocci

diff --git a/tools/pycocci b/tools/pycocci
new file mode 100755
index 0000000..fde8190
--- /dev/null
+++ b/tools/pycocci
@@ -0,0 +1,180 @@
+#!/usr/bin/env python
+#
+# Copyright (c) 2014 Luis R. Rodriguez  <mcgrof@xxxxxxxx>
+# Copyright (c) 2013 Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
+#
+# This file is released under the GPLv2.
+#
+# Python wrapper for Coccinelle for multithreaded support,
+# designed to be used for working on a git tree, and with sensible
+# defaults, specifically for kernel developers.
+
+from multiprocessing import Process, cpu_count, Queue
+import argparse, subprocess, os, sys
+import tempfile, shutil
+
+# simple tempdir wrapper object for 'with' statement
+#
+# Usage:
+# with tempdir.tempdir() as tmpdir:
+#     os.chdir(tmpdir)
+#     do something
+#
+class tempdir(object):
+    def __init__(self, suffix='', prefix='', dir=None, nodelete=False):
+        self.suffix = ''
+        self.prefix = ''
+        self.dir = dir
+        self.nodelete = nodelete
+
+    def __enter__(self):
+        self._name = tempfile.mkdtemp(suffix=self.suffix,
+                                      prefix=self.prefix,
+                                      dir=self.dir)
+        return self._name
+
+    def __exit__(self, type, value, traceback):
+        if self.nodelete:
+            print('not deleting directory %s!' % self._name)
+        else:
+            shutil.rmtree(self._name)
+
+class CoccinelleError(Exception):
+    pass
+class ExecutionError(CoccinelleError):
+    def __init__(self, cmd, errcode):
+        self.error_code = errcode
+        print('Failed command:')
+        print(' '.join(cmd))
+
+class ExecutionErrorThread(CoccinelleError):
+    def __init__(self, errcode, fn, cocci_file, threads, t, logwrite, print_name):
+        self.error_code = errcode
+        logwrite("Failed to apply changes from %s" % print_name)
+
+        logwrite("Specific log output from change that failed using %s" % print_name)
+        tf = open(fn, 'r')
+        for line in tf.read():
+            logwrite('> %s' % line)
+        tf.close()
+
+        logwrite("Full log using %s" % print_name)
+        for num in range(threads):
+            fn = os.path.join(t, '.tmp_spatch_worker.' + str(num))
+            if (not os.path.isfile(fn)):
+                continue
+            tf = open(fn, 'r')
+            for line in tf.read():
+                logwrite('> %s' % line)
+            tf.close()
+            os.unlink(fn)
+
+def spatch(cocci_file, outdir,
+           max_threads, thread_id, temp_dir, ret_q, extra_args=[]):
+    cmd = ['spatch',
+            '--sp-file', cocci_file,
+            '--in-place',
+            '--recursive-includes',
+            '--relax-include-path',
+            '--use-coccigrep',
+            '--timeout', '120',
+            '--dir', outdir ]
+
+    if (max_threads > 1):
+        cmd.extend(['-max', str(max_threads), '-index', str(thread_id)])
+
+    cmd.extend(extra_args)
+
+    fn = os.path.join(temp_dir, '.tmp_spatch_worker.' + str(thread_id))
+    outfile = open(fn, 'w')
+
+    sprocess = subprocess.Popen(cmd,
+                               stdout=outfile, stderr=subprocess.STDOUT,
+                               close_fds=True, universal_newlines=True)
+    sprocess.wait()
+    if sprocess.returncode != 0:
+        raise ExecutionError(cmd, sprocess.returncode)
+    outfile.close()
+    ret_q.put((sprocess.returncode, fn))
+
+def threaded_spatch(cocci_file, outdir, logwrite, num_jobs,
+                    print_name, extra_args=[]):
+    num_cpus = cpu_count()
+    if num_jobs:
+        threads = int(num_jobs)
+    else:
+        threads = num_cpus
+    jobs = list()
+    output = ""
+    ret_q = Queue()
+    with tempdir() as t:
+        for num in range(threads):
+            p = Process(target=spatch, args=(cocci_file, outdir,
+                                             threads, num, t, ret_q,
+                                             extra_args))
+            jobs.append(p)
+        for p in jobs:
+            p.start()
+
+        for num in range(threads):
+            ret, fn = ret_q.get()
+            if ret != 0:
+                raise ExecutionErrorThread(ret, fn, cocci_file, threads, t,
+                                           logwrite, print_name)
+        for job in jobs:
+            p.join()
+
+        for num in range(threads):
+            fn = os.path.join(t, '.tmp_spatch_worker.' + str(num))
+            tf = open(fn, 'r')
+            output = output + tf.read()
+            tf.close()
+            os.unlink(fn)
+        return output
+
+def logwrite(msg):
+    sys.stdout.write(msg)
+    sys.stdout.flush()
+
+def _main():
+    parser = argparse.ArgumentParser(description='Multithreaded Python wrapper for Coccinelle ' +
+                                     'with sensible defaults, targetted specifically ' +
+                                     'for git development environments')
+    parser.add_argument('cocci_file', metavar='<Coccinelle SmPL rules file>', type=str,
+                        help='This is the Coccinelle file you want to use')
+    parser.add_argument('target_dir', metavar='<target directory>', type=str,
+                        help='Target source directory to modify')
+    parser.add_argument('-p', '--profile-cocci', const=True, default=False, action="store_const",
+                        help='Enable profile, this will pass --profile  to Coccinelle.')
+    parser.add_argument('-j', '--jobs', metavar='<jobs>', type=str, default=None,
+                        help='Only use the cocci file passed for Coccinelle, don\'t do anything else, ' +
+                        'also creates a git repo on the target directory for easy inspection ' +
+                        'of changes done by Coccinelle.')
+    parser.add_argument('-v', '--verbose', const=True, default=False, action="store_const",
+                        help='Enable output from Coccinelle')
+    args = parser.parse_args()
+
+    if not os.path.isfile(args.cocci_file):
+        return -2
+
+    extra_spatch_args = []
+    if args.profile_cocci:
+        extra_spatch_args.append('--profile')
+    jobs = 0
+    if args.jobs > 0:
+        jobs = args.jobs
+
+    output = threaded_spatch(args.cocci_file,
+                             args.target_dir,
+                             logwrite,
+                             jobs,
+                             os.path.basename(args.cocci_file),
+                             extra_args=extra_spatch_args)
+    if args.verbose:
+        logwrite(output)
+    return 0
+
+if __name__ == '__main__':
+    ret = _main()
+    if ret:
+        sys.exit(ret)
-- 
1.9.1

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