Issue #14626: Large refactoring of functions / parameters in the os module.
Many functions now support "dir_fd" and "follow_symlinks" parameters;
some also support accepting an open file descriptor in place of of a path
string. Added os.support_* collections as LBYL helpers. Removed many
functions only previously seen in 3.3 alpha releases (often starting with
"f" or "l", or ending with "at"). Originally suggested by Serhiy Storchaka;
implemented by Larry Hastings.
diff --git a/Lib/os.py b/Lib/os.py
index 261a39e..fc8b92e 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -56,9 +56,10 @@
pass
import posixpath as path
- import posix
- __all__.extend(_get_exports_list(posix))
- del posix
+ try:
+ from posix import _have_functions
+ except ImportError:
+ pass
elif 'nt' in _names:
name = 'nt'
@@ -75,6 +76,11 @@
__all__.extend(_get_exports_list(nt))
del nt
+ try:
+ from nt import _have_functions
+ except ImportError:
+ pass
+
elif 'os2' in _names:
name = 'os2'
linesep = '\r\n'
@@ -94,6 +100,11 @@
__all__.extend(_get_exports_list(os2))
del os2
+ try:
+ from os2 import _have_functions
+ except ImportError:
+ pass
+
elif 'ce' in _names:
name = 'ce'
linesep = '\r\n'
@@ -110,6 +121,11 @@
__all__.extend(_get_exports_list(ce))
del ce
+ try:
+ from ce import _have_functions
+ except ImportError:
+ pass
+
else:
raise ImportError('no os specific module found')
@@ -119,6 +135,84 @@
del _names
+
+if _exists("_have_functions"):
+ _globals = globals()
+ def _add(str, fn):
+ if (fn in _globals) and (str in _have_functions):
+ _set.add(_globals[fn])
+
+ _set = set()
+ _add("HAVE_FACCESSAT", "access")
+ _add("HAVE_FCHMODAT", "chmod")
+ _add("HAVE_FCHOWNAT", "chown")
+ _add("HAVE_FSTATAT", "stat")
+ _add("HAVE_FUTIMESAT", "utime")
+ _add("HAVE_LINKAT", "link")
+ _add("HAVE_MKDIRAT", "mkdir")
+ _add("HAVE_MKFIFOAT", "mkfifo")
+ _add("HAVE_MKNODAT", "mknod")
+ _add("HAVE_OPENAT", "open")
+ _add("HAVE_READLINKAT", "readlink")
+ _add("HAVE_RENAMEAT", "rename")
+ _add("HAVE_SYMLINKAT", "symlink")
+ _add("HAVE_UNLINKAT", "unlink")
+ _add("HAVE_UTIMENSAT", "utime")
+ supports_dir_fd = _set
+
+ _set = set()
+ _add("HAVE_FACCESSAT", "access")
+ supports_effective_ids = _set
+
+ _set = set()
+ _add("HAVE_FCHDIR", "chdir")
+ _add("HAVE_FCHMOD", "chmod")
+ _add("HAVE_FCHOWN", "chown")
+ _add("HAVE_FDOPENDIR", "listdir")
+ _add("HAVE_FEXECVE", "execve")
+ _set.add(stat) # fstat always works
+ _add("HAVE_FUTIMENS", "utime")
+ _add("HAVE_FUTIMES", "utime")
+ if _exists("statvfs") and _exists("fstatvfs"): # mac os x10.3
+ _add("HAVE_FSTATVFS", "statvfs")
+ supports_fd = _set
+
+ _set = set()
+ _add("HAVE_FACCESSAT", "access")
+ # Current linux (kernel 3.2, glibc 2.15) doesn't support lchmod.
+ # (The function exists, but it's a stub that always returns ENOSUP.)
+ # Now, linux *does* have fchmodat, which says it can ignore
+ # symbolic links. But that doesn't work either (also returns ENOSUP).
+ # I'm guessing that if they fix fchmodat, they'll also add lchmod at
+ # the same time. So, for now, assume that fchmodat doesn't support
+ # follow_symlinks unless lchmod works.
+ if ((sys.platform != "linux") or
+ ("HAVE_LCHMOD" in _have_functions)):
+ _add("HAVE_FCHMODAT", "chmod")
+ _add("HAVE_FCHOWNAT", "chown")
+ _add("HAVE_FSTATAT", "stat")
+ _add("HAVE_LCHFLAGS", "chflags")
+ _add("HAVE_LCHMOD", "chmod")
+ if _exists("lchown"): # mac os x10.3
+ _add("HAVE_LCHOWN", "chown")
+ _add("HAVE_LINKAT", "link")
+ _add("HAVE_LUTIMES", "utime")
+ _add("HAVE_LSTAT", "stat")
+ _add("HAVE_FSTATAT", "stat")
+ _add("HAVE_UTIMENSAT", "utime")
+ _add("MS_WINDOWS", "stat")
+ supports_follow_symlinks = _set
+
+ _set = set()
+ _add("HAVE_UNLINKAT", "unlink")
+ supports_remove_directory = _set
+
+ del _set
+ del _have_functions
+ del _globals
+ del _add
+
+
# Python uses fixed values for the SEEK_ constants; they are mapped
# to native constants if necessary in posixmodule.c
# Other possible SEEK values are directly imported from posixmodule.c
@@ -318,7 +412,7 @@
__all__.append("walk")
-if _exists("openat"):
+if open in supports_dir_fd:
def fwalk(top, topdown=True, onerror=None, followlinks=False):
"""Directory tree generator.
@@ -343,7 +437,7 @@
import os
for root, dirs, files, rootfd in os.fwalk('python/Lib/email'):
print(root, "consumes", end="")
- print(sum([os.fstatat(rootfd, name).st_size for name in files]),
+ print(sum([os.stat(name, dir_fd=rootfd).st_size for name in files]),
end="")
print("bytes in", len(files), "non-directory files")
if 'CVS' in dirs:
@@ -365,10 +459,7 @@
# necessary, it can be adapted to only require O(1) FDs, see issue
# #13734.
- # whether to follow symlinks
- flag = 0 if followlinks else AT_SYMLINK_NOFOLLOW
-
- names = flistdir(topfd)
+ names = listdir(topfd)
dirs, nondirs = [], []
for name in names:
try:
@@ -376,14 +467,14 @@
# walk() which reports symlinks to directories as directories.
# We do however check for symlinks before recursing into
# a subdirectory.
- if st.S_ISDIR(fstatat(topfd, name).st_mode):
+ if st.S_ISDIR(stat(name, dir_fd=topfd).st_mode):
dirs.append(name)
else:
nondirs.append(name)
except FileNotFoundError:
try:
# Add dangling symlinks, ignore disappeared files
- if st.S_ISLNK(fstatat(topfd, name, AT_SYMLINK_NOFOLLOW)
+ if st.S_ISLNK(stat(name, dir_fd=topfd, follow_symlinks=False)
.st_mode):
nondirs.append(name)
except FileNotFoundError:
@@ -394,8 +485,8 @@
for name in dirs:
try:
- orig_st = fstatat(topfd, name, flag)
- dirfd = openat(topfd, name, O_RDONLY)
+ orig_st = stat(name, dir_fd=topfd, follow_symlinks=followlinks)
+ dirfd = open(name, O_RDONLY, dir_fd=topfd)
except error as err:
if onerror is not None:
onerror(err)