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python2: backport fix for pyc race condition, part 2

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Turns out fixing this only in importlib is not sufficient and we
need to backport CPython part of the fix too.

This patch is based on https://hg.python.org/cpython/rev/c16063765d3a
but because the code around is different there are some changes (C-strings
instead of Python objects etc.)

With this patch Tensorflow builds successfully on many-core machine.
This commit is contained in:
Nikolay Amiantov 2019-07-16 14:59:38 +03:00 committed by Frederik Rietdijk
parent 9a6bd59111
commit da295a1206
1 changed files with 76 additions and 1 deletions
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77
pkgs/development/interpreters/python/cpython/2.7/atomic_pyc.patch
View file

@ -1,5 +1,5 @@
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
index 978da73..3559eb9 100644
index 978da73d74..3559eb95ca 100644
--- a/Lib/py_compile.py
+++ b/Lib/py_compile.py
@@ -120,16 +120,27 @@ def compile(file, cfile=None, dfile=None, doraise=False):
@ -39,3 +39,78 @@ index 978da73..3559eb9 100644
def main(args=None):
"""Compile several source files.
diff --git a/Python/import.c b/Python/import.c
index 1e31d79279..f78a1efcf0 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -951,6 +951,8 @@ static void
write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat, time_t mtime)
{
FILE *fp;
+ size_t cpathname_len;
+ char *cpathname_tmp;
#ifdef MS_WINDOWS /* since Windows uses different permissions */
mode_t mode = srcstat->st_mode & ~S_IEXEC;
/* Issue #6074: We ensure user write access, so we can delete it later
@@ -963,11 +965,28 @@ write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat, t
mode_t mode = srcstat->st_mode & ~S_IXUSR & ~S_IXGRP & ~S_IXOTH;
#endif
+#ifdef MS_WINDOWS
fp = open_exclusive(cpathname, mode);
+#else
+ /* Under POSIX, we first write to a tmp file and then take advantage
+ of atomic renaming. */
+ cpathname_len = strlen(cpathname);
+ cpathname_tmp = PyMem_MALLOC(cpathname_len + 5);
+ if (cpathname_tmp == NULL) {
+ PyErr_Clear();
+ return;
+ }
+ memcpy(cpathname_tmp, cpathname, cpathname_len);
+ memcpy(cpathname_tmp + cpathname_len, ".tmp", 5);
+ fp = open_exclusive(cpathname_tmp, mode);
+#endif
if (fp == NULL) {
if (Py_VerboseFlag)
PySys_WriteStderr(
"# can't create %s\n", cpathname);
+#ifndef MS_WINDOWS
+ PyMem_FREE(cpathname_tmp);
+#endif
return;
}
PyMarshal_WriteLongToFile(pyc_magic, fp, Py_MARSHAL_VERSION);
@@ -979,7 +998,12 @@ write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat, t
PySys_WriteStderr("# can't write %s\n", cpathname);
/* Don't keep partial file */
fclose(fp);
+#ifdef MS_WINDOWS
(void) unlink(cpathname);
+#else
+ (void) unlink(cpathname_tmp);
+ PyMem_FREE(cpathname_tmp);
+#endif
return;
}
/* Now write the true mtime (as a 32-bit field) */
@@ -989,6 +1013,19 @@ write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat, t
PyMarshal_WriteLongToFile((long)mtime, fp, Py_MARSHAL_VERSION);
fflush(fp);
}
+ /* Under POSIX, do an atomic rename */
+#ifndef MS_WINDOWS
+ if (rename(cpathname_tmp, cpathname)) {
+ if (Py_VerboseFlag)
+ PySys_WriteStderr("# can't write %s\n", cpathname);
+ /* Don't keep tmp file */
+ fclose(fp);
+ (void) unlink(cpathname_tmp);
+ PyMem_FREE(cpathname_tmp);
+ return;
+ }
+ PyMem_FREE(cpathname_tmp);
+#endif
fclose(fp);
if (Py_VerboseFlag)
PySys_WriteStderr("# wrote %s\n", cpathname);