Mercurial > hg
view mercurial/scmposix.py @ 40626:87a872555e90
revlog: detect incomplete revlog reads
_readsegment() is supposed to return N bytes of revlog revision
data starting at a file offset. Surprisingly, its behavior before
this patch never verified that it actually read and returned N
bytes! Instead, it would perform the read(), then return whatever
data was available. And even more surprisingly, nothing in the
call chain appears to have been validating that it received all
the data it was expecting.
This behavior could lead to partial or incomplete revision chunks
being operated on. This could result in e.g. cached deltas being
applied against incomplete base revisions. The delta application
process would happily perform this operation. Only hash
verification would detect the corruption and save us.
This commit changes the behavior of raw revlog reading to validate
that we actually read() the number of bytes that were requested.
We will raise a more specific error faster, rather than possibly
have it go undetected or manifest later in the call stack, at
delta application or hash verification.
Differential Revision: https://phab.mercurial-scm.org/D5266
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 13 Nov 2018 12:30:59 -0800 |
parents | dacfcdd8b94e |
children | 57875cf423c9 |
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from __future__ import absolute_import import array import errno import fcntl import os import sys from . import ( encoding, pycompat, util, ) # BSD 'more' escapes ANSI color sequences by default. This can be disabled by # $MORE variable, but there's no compatible option with Linux 'more'. Given # OS X is widely used and most modern Unix systems would have 'less', setting # 'less' as the default seems reasonable. fallbackpager = 'less' def _rcfiles(path): rcs = [os.path.join(path, 'hgrc')] rcdir = os.path.join(path, 'hgrc.d') try: rcs.extend([os.path.join(rcdir, f) for f, kind in util.listdir(rcdir) if f.endswith(".rc")]) except OSError: pass return rcs def systemrcpath(): path = [] if pycompat.sysplatform == 'plan9': root = 'lib/mercurial' else: root = 'etc/mercurial' # old mod_python does not set sys.argv if len(getattr(sys, 'argv', [])) > 0: p = os.path.dirname(os.path.dirname(pycompat.sysargv[0])) if p != '/': path.extend(_rcfiles(os.path.join(p, root))) path.extend(_rcfiles('/' + root)) return path def userrcpath(): if pycompat.sysplatform == 'plan9': return [encoding.environ['home'] + '/lib/hgrc'] elif pycompat.isdarwin: return [os.path.expanduser('~/.hgrc')] else: confighome = encoding.environ.get('XDG_CONFIG_HOME') if confighome is None or not os.path.isabs(confighome): confighome = os.path.expanduser('~/.config') return [os.path.expanduser('~/.hgrc'), os.path.join(confighome, 'hg', 'hgrc')] def termsize(ui): try: import termios TIOCGWINSZ = termios.TIOCGWINSZ # unavailable on IRIX (issue3449) except (AttributeError, ImportError): return 80, 24 for dev in (ui.ferr, ui.fout, ui.fin): try: try: fd = dev.fileno() except AttributeError: continue if not os.isatty(fd): continue arri = fcntl.ioctl(fd, TIOCGWINSZ, '\0' * 8) height, width = array.array(r'h', arri)[:2] if width > 0 and height > 0: return width, height except ValueError: pass except IOError as e: if e[0] == errno.EINVAL: pass else: raise return 80, 24