dirs: resolve fuzzer OOM situation by disallowing deep directory hierarchies
It seems like 2048 directories ought to be enough for any reasonable
use of Mercurial?
A previous version of this patch scanned for slashes before any allocations
occurred. That approach is slower than this in the happy path, but much faster
than this in the case that too many slashes are encountered. We may want to
revisit it in the future using memchr() so it'll be well-optimized by the libc
we're using.
.. bc:
Mercurial will now defend against OOMs by refusing to operate on
paths with 2048 or more components. This means that _extremely_
deep path hierarchies will be rejected, but we anticipate nobody
is using hierarchies this deep.
Differential Revision: https://phab.mercurial-scm.org/D7411
# memory.py - track memory usage
#
# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''helper extension to measure memory usage
Reads current and peak memory usage from ``/proc/self/status`` and
prints it to ``stderr`` on exit.
'''
from __future__ import absolute_import
def memusage(ui):
"""Report memory usage of the current process."""
result = {'peak': 0, 'rss': 0}
with open('/proc/self/status', 'r') as status:
# This will only work on systems with a /proc file system
# (like Linux).
for line in status:
parts = line.split()
key = parts[0][2:-1].lower()
if key in result:
result[key] = int(parts[1])
ui.write_err(
", ".join(
["%s: %.1f MiB" % (k, v / 1024.0) for k, v in result.iteritems()]
)
+ "\n"
)
def extsetup(ui):
ui.atexit(memusage, ui)