From de68722ca06615692613148b7015b3c62cd043c3 Mon Sep 17 00:00:00 2001 From: Antoine Pitrou Date: Sun, 29 Jun 2014 20:07:28 -0400 Subject: Issue #21679: Prevent extraneous fstat() calls during open(). Patch by Bohuslav Kabrda. --- Lib/test/test_fileio.py | 11 ++++++++++- Misc/NEWS | 3 +++ Modules/_io/_iomodule.c | 28 +++++++++------------------- Modules/_io/fileio.c | 46 +++++++++++++++++++++++++--------------------- 4 files changed, 47 insertions(+), 41 deletions(-) diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py index c37482e..b87dc07 100644 --- a/Lib/test/test_fileio.py +++ b/Lib/test/test_fileio.py @@ -60,6 +60,15 @@ class AutoFileTests(unittest.TestCase): self.assertRaises((AttributeError, TypeError), setattr, f, attr, 'oops') + def testBlksize(self): + # test private _blksize attribute + blksize = io.DEFAULT_BUFFER_SIZE + # try to get preferred blksize from stat.st_blksize, if available + if hasattr(os, 'fstat'): + fst = os.fstat(self.f.fileno()) + blksize = getattr(fst, 'st_blksize', blksize) + self.assertEqual(self.f._blksize, blksize) + def testReadinto(self): # verify readinto self.f.write(bytes([1, 2])) @@ -141,7 +150,7 @@ class AutoFileTests(unittest.TestCase): def testOpendir(self): # Issue 3703: opening a directory should fill the errno # Windows always returns "[Errno 13]: Permission denied - # Unix calls dircheck() and returns "[Errno 21]: Is a directory" + # Unix uses fstat and returns "[Errno 21]: Is a directory" try: _FileIO('.', 'r') except OSError as e: diff --git a/Misc/NEWS b/Misc/NEWS index d7bc2af..27effe8 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -103,6 +103,9 @@ Core and Builtins Library ------- +- Issue #21679: Prevent extraneous fstat() calls during open(). Patch by + Bohuslav Kabrda. + - Issue #21863: cProfile now displays the module name of C extension functions, in addition to their own name. diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c index 660ff1f..9e14b4f 100644 --- a/Modules/_io/_iomodule.c +++ b/Modules/_io/_iomodule.c @@ -237,8 +237,8 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds) PyObject *raw, *modeobj = NULL, *buffer, *wrapper, *result = NULL; + _Py_IDENTIFIER(_blksize); _Py_IDENTIFIER(isatty); - _Py_IDENTIFIER(fileno); _Py_IDENTIFIER(mode); _Py_IDENTIFIER(close); @@ -380,24 +380,14 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds) line_buffering = 0; if (buffering < 0) { - buffering = DEFAULT_BUFFER_SIZE; -#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE - { - struct stat st; - long fileno; - PyObject *res = _PyObject_CallMethodId(raw, &PyId_fileno, NULL); - if (res == NULL) - goto error; - - fileno = PyLong_AsLong(res); - Py_DECREF(res); - if (fileno == -1 && PyErr_Occurred()) - goto error; - - if (fstat(fileno, &st) >= 0 && st.st_blksize > 1) - buffering = st.st_blksize; - } -#endif + PyObject *blksize_obj; + blksize_obj = _PyObject_GetAttrId(raw, &PyId__blksize); + if (blksize_obj == NULL) + goto error; + buffering = PyLong_AsLong(blksize_obj); + Py_DECREF(blksize_obj); + if (buffering == -1 && PyErr_Occurred()) + goto error; } if (buffering < 0) { PyErr_SetString(PyExc_ValueError, diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c index cbb2daf..038b2c6 100644 --- a/Modules/_io/fileio.c +++ b/Modules/_io/fileio.c @@ -53,6 +53,7 @@ typedef struct { signed int seekable : 2; /* -1 means unknown */ unsigned int closefd : 1; char finalizing; + unsigned int blksize; PyObject *weakreflist; PyObject *dict; } fileio; @@ -161,6 +162,7 @@ fileio_new(PyTypeObject *type, PyObject *args, PyObject *kwds) self->writable = 0; self->appending = 0; self->seekable = -1; + self->blksize = 0; self->closefd = 1; self->weakreflist = NULL; } @@ -168,26 +170,6 @@ fileio_new(PyTypeObject *type, PyObject *args, PyObject *kwds) return (PyObject *) self; } -/* On Unix, open will succeed for directories. - In Python, there should be no file objects referring to - directories, so we need a check. */ - -static int -dircheck(fileio* self, PyObject *nameobj) -{ -#if defined(HAVE_FSTAT) && defined(S_ISDIR) && defined(EISDIR) - struct stat buf; - if (self->fd < 0) - return 0; - if (fstat(self->fd, &buf) == 0 && S_ISDIR(buf.st_mode)) { - errno = EISDIR; - PyErr_SetFromErrnoWithFilenameObject(PyExc_IOError, nameobj); - return -1; - } -#endif - return 0; -} - static int check_fd(int fd) { @@ -233,6 +215,9 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds) #elif !defined(MS_WINDOWS) int *atomic_flag_works = NULL; #endif +#ifdef HAVE_FSTAT + struct stat fdfstat; +#endif assert(PyFileIO_Check(oself)); if (self->fd >= 0) { @@ -421,8 +406,26 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds) goto error; #endif } - if (dircheck(self, nameobj) < 0) + + self->blksize = DEFAULT_BUFFER_SIZE; +#ifdef HAVE_FSTAT + if (fstat(self->fd, &fdfstat) < 0) goto error; +#if defined(S_ISDIR) && defined(EISDIR) + /* On Unix, open will succeed for directories. + In Python, there should be no file objects referring to + directories, so we need a check. */ + if (S_ISDIR(fdfstat.st_mode)) { + errno = EISDIR; + PyErr_SetFromErrnoWithFilenameObject(PyExc_IOError, nameobj); + goto error; + } +#endif /* defined(S_ISDIR) */ +#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE + if (fdfstat.st_blksize > 1) + self->blksize = fdfstat.st_blksize; +#endif /* HAVE_STRUCT_STAT_ST_BLKSIZE */ +#endif /* HAVE_FSTAT */ #if defined(MS_WINDOWS) || defined(__CYGWIN__) /* don't translate newlines (\r\n <=> \n) */ @@ -1216,6 +1219,7 @@ static PyGetSetDef fileio_getsetlist[] = { }; static PyMemberDef fileio_members[] = { + {"_blksize", T_UINT, offsetof(fileio, blksize), 0}, {"_finalizing", T_BOOL, offsetof(fileio, finalizing), 0}, {NULL} }; -- cgit v0.12