/usr/lib/python2.7/posixfile.py is in libpython2.7-stdlib 2.7.11-7ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 | """Extended file operations available in POSIX.
f = posixfile.open(filename, [mode, [bufsize]])
will create a new posixfile object
f = posixfile.fileopen(fileobject)
will create a posixfile object from a builtin file object
f.file()
will return the original builtin file object
f.dup()
will return a new file object based on a new filedescriptor
f.dup2(fd)
will return a new file object based on the given filedescriptor
f.flags(mode)
will turn on the associated flag (merge)
mode can contain the following characters:
(character representing a flag)
a append only flag
c close on exec flag
n no delay flag
s synchronization flag
(modifiers)
! turn flags 'off' instead of default 'on'
= copy flags 'as is' instead of default 'merge'
? return a string in which the characters represent the flags
that are set
note: - the '!' and '=' modifiers are mutually exclusive.
- the '?' modifier will return the status of the flags after they
have been changed by other characters in the mode string
f.lock(mode [, len [, start [, whence]]])
will (un)lock a region
mode can contain the following characters:
(character representing type of lock)
u unlock
r read lock
w write lock
(modifiers)
| wait until the lock can be granted
? return the first lock conflicting with the requested lock
or 'None' if there is no conflict. The lock returned is in the
format (mode, len, start, whence, pid) where mode is a
character representing the type of lock ('r' or 'w')
note: - the '?' modifier prevents a region from being locked; it is
query only
"""
import warnings
warnings.warn("The posixfile module is deprecated; "
"fcntl.lockf() provides better locking", DeprecationWarning, 2)
class _posixfile_:
"""File wrapper class that provides extra POSIX file routines."""
states = ['open', 'closed']
#
# Internal routines
#
def __repr__(self):
file = self._file_
return "<%s posixfile '%s', mode '%s' at %s>" % \
(self.states[file.closed], file.name, file.mode, \
hex(id(self))[2:])
#
# Initialization routines
#
def open(self, name, mode='r', bufsize=-1):
import __builtin__
return self.fileopen(__builtin__.open(name, mode, bufsize))
def fileopen(self, file):
import types
if repr(type(file)) != "<type 'file'>":
raise TypeError, 'posixfile.fileopen() arg must be file object'
self._file_ = file
# Copy basic file methods
for maybemethod in dir(file):
if not maybemethod.startswith('_'):
attr = getattr(file, maybemethod)
if isinstance(attr, types.BuiltinMethodType):
setattr(self, maybemethod, attr)
return self
#
# New methods
#
def file(self):
return self._file_
def dup(self):
import posix
if not hasattr(posix, 'fdopen'):
raise AttributeError, 'dup() method unavailable'
return posix.fdopen(posix.dup(self._file_.fileno()), self._file_.mode)
def dup2(self, fd):
import posix
if not hasattr(posix, 'fdopen'):
raise AttributeError, 'dup() method unavailable'
posix.dup2(self._file_.fileno(), fd)
return posix.fdopen(fd, self._file_.mode)
def flags(self, *which):
import fcntl, os
if which:
if len(which) > 1:
raise TypeError, 'Too many arguments'
which = which[0]
else: which = '?'
l_flags = 0
if 'n' in which: l_flags = l_flags | os.O_NDELAY
if 'a' in which: l_flags = l_flags | os.O_APPEND
if 's' in which: l_flags = l_flags | os.O_SYNC
file = self._file_
if '=' not in which:
cur_fl = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0)
if '!' in which: l_flags = cur_fl & ~ l_flags
else: l_flags = cur_fl | l_flags
l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFL, l_flags)
if 'c' in which:
arg = ('!' not in which) # 0 is don't, 1 is do close on exec
l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFD, arg)
if '?' in which:
which = '' # Return current flags
l_flags = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0)
if os.O_APPEND & l_flags: which = which + 'a'
if fcntl.fcntl(file.fileno(), fcntl.F_GETFD, 0) & 1:
which = which + 'c'
if os.O_NDELAY & l_flags: which = which + 'n'
if os.O_SYNC & l_flags: which = which + 's'
return which
def lock(self, how, *args):
import struct, fcntl
if 'w' in how: l_type = fcntl.F_WRLCK
elif 'r' in how: l_type = fcntl.F_RDLCK
elif 'u' in how: l_type = fcntl.F_UNLCK
else: raise TypeError, 'no type of lock specified'
if '|' in how: cmd = fcntl.F_SETLKW
elif '?' in how: cmd = fcntl.F_GETLK
else: cmd = fcntl.F_SETLK
l_whence = 0
l_start = 0
l_len = 0
if len(args) == 1:
l_len = args[0]
elif len(args) == 2:
l_len, l_start = args
elif len(args) == 3:
l_len, l_start, l_whence = args
elif len(args) > 3:
raise TypeError, 'too many arguments'
# Hack by davem@magnet.com to get locking to go on freebsd;
# additions for AIX by Vladimir.Marangozov@imag.fr
import sys, os
if sys.platform in ('netbsd1',
'openbsd2',
'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5',
'freebsd6', 'freebsd7', 'freebsd8',
'bsdos2', 'bsdos3', 'bsdos4'):
flock = struct.pack('lxxxxlxxxxlhh', \
l_start, l_len, os.getpid(), l_type, l_whence)
elif sys.platform in ('aix3', 'aix4'):
flock = struct.pack('hhlllii', \
l_type, l_whence, l_start, l_len, 0, 0, 0)
else:
flock = struct.pack('hhllhh', \
l_type, l_whence, l_start, l_len, 0, 0)
flock = fcntl.fcntl(self._file_.fileno(), cmd, flock)
if '?' in how:
if sys.platform in ('netbsd1',
'openbsd2',
'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5',
'bsdos2', 'bsdos3', 'bsdos4'):
l_start, l_len, l_pid, l_type, l_whence = \
struct.unpack('lxxxxlxxxxlhh', flock)
elif sys.platform in ('aix3', 'aix4'):
l_type, l_whence, l_start, l_len, l_sysid, l_pid, l_vfs = \
struct.unpack('hhlllii', flock)
elif sys.platform == "linux2":
l_type, l_whence, l_start, l_len, l_pid, l_sysid = \
struct.unpack('hhllhh', flock)
else:
l_type, l_whence, l_start, l_len, l_sysid, l_pid = \
struct.unpack('hhllhh', flock)
if l_type != fcntl.F_UNLCK:
if l_type == fcntl.F_RDLCK:
return 'r', l_len, l_start, l_whence, l_pid
else:
return 'w', l_len, l_start, l_whence, l_pid
def open(name, mode='r', bufsize=-1):
"""Public routine to open a file as a posixfile object."""
return _posixfile_().open(name, mode, bufsize)
def fileopen(file):
"""Public routine to get a posixfile object from a Python file object."""
return _posixfile_().fileopen(file)
#
# Constants
#
SEEK_SET = 0
SEEK_CUR = 1
SEEK_END = 2
#
# End of posixfile.py
#
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