changeset 29017:07be86828e79 stable

util: fix race in makedirs() Update makedirs() to ignore EEXIST in case someone else has already created the directory in question. Previously the ensuredirs() function existed, and was nearly identical to makedirs() except that it fixed this race. Unfortunately ensuredirs() was only used in 3 places, and most code uses the racy makedirs() function. This fixes makedirs() to be non-racy, and replaces calls to ensuredirs() with makedirs(). In particular, mercurial.scmutil.origpath() used the racy makedirs() code, which could cause failures during "hg update" as it tried to create backup directories. This does slightly change the behavior of call sites using ensuredirs(): previously ensuredirs() would throw EEXIST if the path existed but was a regular file instead of a directory. It did this by explicitly checking os.path.isdir() after getting EEXIST. The makedirs() code did not do this and swallowed all EEXIST errors. I kept the makedirs() behavior, since it seemed preferable to avoid the extra stat call in the common case where this directory already exists. If the path does happen to be a file, the caller will almost certainly fail with an ENOTDIR error shortly afterwards anyway. I checked the 3 existing call sites of ensuredirs(), and this seems to be the case for them.
author Adam Simpkins <simpkins@fb.com>
date Tue, 26 Apr 2016 15:32:59 -0700
parents 94451300f3ec
children 602cc9bf036e
files mercurial/scmutil.py mercurial/util.py
diffstat 2 files changed, 16 insertions(+), 27 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/scmutil.py	Sun Apr 24 21:35:30 2016 +0900
+++ b/mercurial/scmutil.py	Tue Apr 26 15:32:59 2016 -0700
@@ -539,7 +539,7 @@
             # to a directory. Let the posixfile() call below raise IOError.
             if basename:
                 if atomictemp:
-                    util.ensuredirs(dirname, self.createmode, notindexed)
+                    util.makedirs(dirname, self.createmode, notindexed)
                     return util.atomictempfile(f, mode, self.createmode)
                 try:
                     if 'w' in mode:
@@ -556,7 +556,7 @@
                     if e.errno != errno.ENOENT:
                         raise
                     nlink = 0
-                    util.ensuredirs(dirname, self.createmode, notindexed)
+                    util.makedirs(dirname, self.createmode, notindexed)
                 if nlink > 0:
                     if self._trustnlink is None:
                         self._trustnlink = nlink > 1 or util.checknlink(f)
@@ -583,7 +583,7 @@
         except OSError:
             pass
 
-        util.ensuredirs(os.path.dirname(linkname), self.createmode)
+        util.makedirs(os.path.dirname(linkname), self.createmode)
 
         if self._cansymlink:
             try:
--- a/mercurial/util.py	Sun Apr 24 21:35:30 2016 +0900
+++ b/mercurial/util.py	Tue Apr 26 15:32:59 2016 -0700
@@ -1420,7 +1420,12 @@
             self.discard()
 
 def makedirs(name, mode=None, notindexed=False):
-    """recursive directory creation with parent mode inheritance"""
+    """recursive directory creation with parent mode inheritance
+
+    Newly created directories are marked as "not to be indexed by
+    the content indexing service", if ``notindexed`` is specified
+    for "write" mode access.
+    """
     try:
         makedir(name, notindexed)
     except OSError as err:
@@ -1432,29 +1437,13 @@
         if parent == name:
             raise
         makedirs(parent, mode, notindexed)
-        makedir(name, notindexed)
-    if mode is not None:
-        os.chmod(name, mode)
-
-def ensuredirs(name, mode=None, notindexed=False):
-    """race-safe recursive directory creation
-
-    Newly created directories are marked as "not to be indexed by
-    the content indexing service", if ``notindexed`` is specified
-    for "write" mode access.
-    """
-    if os.path.isdir(name):
-        return
-    parent = os.path.dirname(os.path.abspath(name))
-    if parent != name:
-        ensuredirs(parent, mode, notindexed)
-    try:
-        makedir(name, notindexed)
-    except OSError as err:
-        if err.errno == errno.EEXIST and os.path.isdir(name):
-            # someone else seems to have won a directory creation race
-            return
-        raise
+        try:
+            makedir(name, notindexed)
+        except OSError as err:
+            # Catch EEXIST to handle races
+            if err.errno == errno.EEXIST:
+                return
+            raise
     if mode is not None:
         os.chmod(name, mode)