##// END OF EJS Templates
posix: always seek to EOF when opening a file in append mode...
posix: always seek to EOF when opening a file in append mode Python 3 already does this, so skip it there. Consider the program: #include <stdio.h> int main() { FILE *f = fopen("narf", "w"); fprintf(f, "narf\n"); fclose(f); f = fopen("narf", "a"); printf("%ld\n", ftell(f)); fprintf(f, "troz\n"); printf("%ld\n", ftell(f)); return 0; } on macOS, FreeBSD, and Linux with glibc, this program prints 5 10 but on musl libc (Alpine Linux and probably others) this prints 0 10 By my reading of https://pubs.opengroup.org/onlinepubs/009695399/functions/fopen.html this is technically correct, specifically: > Opening a file with append mode (a as the first character in the > mode argument) shall cause all subsequent writes to the file to be > forced to the then current end-of-file, regardless of intervening > calls to fseek(). in other words, the file position doesn't really matter in append-mode files, and we can't depend on it being at all meaningful unless we perform a seek() before tell() after open(..., 'a'). Experimentally after a .write() we can do a .tell() and it'll always be reasonable, but I'm unclear from reading the specification if that's a smart thing to rely on. This matches what we do on Windows and what Python 3 does for free, so let's just be consistent. Thanks to Yuya for the idea.

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pathutil.py
264 lines | 9.5 KiB | text/x-python | PythonLexer
from __future__ import absolute_import
import errno
import os
import posixpath
import stat
from .i18n import _
from . import (
encoding,
error,
pycompat,
util,
)
def _lowerclean(s):
return encoding.hfsignoreclean(s.lower())
class pathauditor(object):
'''ensure that a filesystem path contains no banned components.
the following properties of a path are checked:
- ends with a directory separator
- under top-level .hg
- starts at the root of a windows drive
- contains ".."
More check are also done about the file system states:
- traverses a symlink (e.g. a/symlink_here/b)
- inside a nested repository (a callback can be used to approve
some nested repositories, e.g., subrepositories)
The file system checks are only done when 'realfs' is set to True (the
default). They should be disable then we are auditing path for operation on
stored history.
If 'cached' is set to True, audited paths and sub-directories are cached.
Be careful to not keep the cache of unmanaged directories for long because
audited paths may be replaced with symlinks.
'''
def __init__(self, root, callback=None, realfs=True, cached=False):
self.audited = set()
self.auditeddir = set()
self.root = root
self._realfs = realfs
self._cached = cached
self.callback = callback
if os.path.lexists(root) and not util.fscasesensitive(root):
self.normcase = util.normcase
else:
self.normcase = lambda x: x
def __call__(self, path, mode=None):
'''Check the relative path.
path may contain a pattern (e.g. foodir/**.txt)'''
path = util.localpath(path)
normpath = self.normcase(path)
if normpath in self.audited:
return
# AIX ignores "/" at end of path, others raise EISDIR.
if util.endswithsep(path):
raise error.Abort(_("path ends in directory separator: %s") % path)
parts = util.splitpath(path)
if (os.path.splitdrive(path)[0]
or _lowerclean(parts[0]) in ('.hg', '.hg.', '')
or pycompat.ospardir in parts):
raise error.Abort(_("path contains illegal component: %s") % path)
# Windows shortname aliases
for p in parts:
if "~" in p:
first, last = p.split("~", 1)
if last.isdigit() and first.upper() in ["HG", "HG8B6C"]:
raise error.Abort(_("path contains illegal component: %s")
% path)
if '.hg' in _lowerclean(path):
lparts = [_lowerclean(p.lower()) for p in parts]
for p in '.hg', '.hg.':
if p in lparts[1:]:
pos = lparts.index(p)
base = os.path.join(*parts[:pos])
raise error.Abort(_("path '%s' is inside nested repo %r")
% (path, pycompat.bytestr(base)))
normparts = util.splitpath(normpath)
assert len(parts) == len(normparts)
parts.pop()
normparts.pop()
prefixes = []
# It's important that we check the path parts starting from the root.
# This means we won't accidentally traverse a symlink into some other
# filesystem (which is potentially expensive to access).
for i in range(len(parts)):
prefix = pycompat.ossep.join(parts[:i + 1])
normprefix = pycompat.ossep.join(normparts[:i + 1])
if normprefix in self.auditeddir:
continue
if self._realfs:
self._checkfs(prefix, path)
prefixes.append(normprefix)
if self._cached:
self.audited.add(normpath)
# only add prefixes to the cache after checking everything: we don't
# want to add "foo/bar/baz" before checking if there's a "foo/.hg"
self.auditeddir.update(prefixes)
def _checkfs(self, prefix, path):
"""raise exception if a file system backed check fails"""
curpath = os.path.join(self.root, prefix)
try:
st = os.lstat(curpath)
except OSError as err:
# EINVAL can be raised as invalid path syntax under win32.
# They must be ignored for patterns can be checked too.
if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL):
raise
else:
if stat.S_ISLNK(st.st_mode):
msg = (_('path %r traverses symbolic link %r')
% (pycompat.bytestr(path), pycompat.bytestr(prefix)))
raise error.Abort(msg)
elif (stat.S_ISDIR(st.st_mode) and
os.path.isdir(os.path.join(curpath, '.hg'))):
if not self.callback or not self.callback(curpath):
msg = _("path '%s' is inside nested repo %r")
raise error.Abort(msg % (path, pycompat.bytestr(prefix)))
def check(self, path):
try:
self(path)
return True
except (OSError, error.Abort):
return False
def canonpath(root, cwd, myname, auditor=None):
'''return the canonical path of myname, given cwd and root
>>> def check(root, cwd, myname):
... a = pathauditor(root, realfs=False)
... try:
... return canonpath(root, cwd, myname, a)
... except error.Abort:
... return 'aborted'
>>> def unixonly(root, cwd, myname, expected='aborted'):
... if pycompat.iswindows:
... return expected
... return check(root, cwd, myname)
>>> def winonly(root, cwd, myname, expected='aborted'):
... if not pycompat.iswindows:
... return expected
... return check(root, cwd, myname)
>>> winonly(b'd:\\\\repo', b'c:\\\\dir', b'filename')
'aborted'
>>> winonly(b'c:\\\\repo', b'c:\\\\dir', b'filename')
'aborted'
>>> winonly(b'c:\\\\repo', b'c:\\\\', b'filename')
'aborted'
>>> winonly(b'c:\\\\repo', b'c:\\\\', b'repo\\\\filename',
... b'filename')
'filename'
>>> winonly(b'c:\\\\repo', b'c:\\\\repo', b'filename', b'filename')
'filename'
>>> winonly(b'c:\\\\repo', b'c:\\\\repo\\\\subdir', b'filename',
... b'subdir/filename')
'subdir/filename'
>>> unixonly(b'/repo', b'/dir', b'filename')
'aborted'
>>> unixonly(b'/repo', b'/', b'filename')
'aborted'
>>> unixonly(b'/repo', b'/', b'repo/filename', b'filename')
'filename'
>>> unixonly(b'/repo', b'/repo', b'filename', b'filename')
'filename'
>>> unixonly(b'/repo', b'/repo/subdir', b'filename', b'subdir/filename')
'subdir/filename'
'''
if util.endswithsep(root):
rootsep = root
else:
rootsep = root + pycompat.ossep
name = myname
if not os.path.isabs(name):
name = os.path.join(root, cwd, name)
name = os.path.normpath(name)
if auditor is None:
auditor = pathauditor(root)
if name != rootsep and name.startswith(rootsep):
name = name[len(rootsep):]
auditor(name)
return util.pconvert(name)
elif name == root:
return ''
else:
# Determine whether `name' is in the hierarchy at or beneath `root',
# by iterating name=dirname(name) until that causes no change (can't
# check name == '/', because that doesn't work on windows). The list
# `rel' holds the reversed list of components making up the relative
# file name we want.
rel = []
while True:
try:
s = util.samefile(name, root)
except OSError:
s = False
if s:
if not rel:
# name was actually the same as root (maybe a symlink)
return ''
rel.reverse()
name = os.path.join(*rel)
auditor(name)
return util.pconvert(name)
dirname, basename = util.split(name)
rel.append(basename)
if dirname == name:
break
name = dirname
# A common mistake is to use -R, but specify a file relative to the repo
# instead of cwd. Detect that case, and provide a hint to the user.
hint = None
try:
if cwd != root:
canonpath(root, root, myname, auditor)
relpath = util.pathto(root, cwd, '')
if relpath.endswith(pycompat.ossep):
relpath = relpath[:-1]
hint = (_("consider using '--cwd %s'") % relpath)
except error.Abort:
pass
raise error.Abort(_("%s not under root '%s'") % (myname, root),
hint=hint)
def normasprefix(path):
'''normalize the specified path as path prefix
Returned value can be used safely for "p.startswith(prefix)",
"p[len(prefix):]", and so on.
For efficiency, this expects "path" argument to be already
normalized by "os.path.normpath", "os.path.realpath", and so on.
See also issue3033 for detail about need of this function.
>>> normasprefix(b'/foo/bar').replace(pycompat.ossep, b'/')
'/foo/bar/'
>>> normasprefix(b'/').replace(pycompat.ossep, b'/')
'/'
'''
d, p = os.path.splitdrive(path)
if len(p) != len(pycompat.ossep):
return path + pycompat.ossep
else:
return path
# forward two methods from posixpath that do what we need, but we'd
# rather not let our internals know that we're thinking in posix terms
# - instead we'll let them be oblivious.
join = posixpath.join
dirname = posixpath.dirname