--- /dev/null
+--- a/Lib/test/test_file2k.py 2018-02-16 17:49:45.180147747 -0500
++++ b/Lib/test/test_file2k.py 2018-02-16 17:51:06.870149602 -0500
+@@ -652,6 +652,33 @@ class FileThreadingTests(unittest.TestCa
+ self.f.writelines('')
+ self._test_close_open_io(io_func)
+
++ def test_iteration_torture(self):
++ # bpo-31530
++ with open(self.filename, "wb") as fp:
++ for i in xrange(2**20):
++ fp.write(b"0"*50 + b"\n")
++ with open(self.filename, "rb") as f:
++ def it():
++ for l in f:
++ pass
++ self._run_workers(it, 10)
++
++ def test_iteration_seek(self):
++ # bpo-31530: Crash when concurrently seek and iterate over a file.
++ with open(self.filename, "wb") as fp:
++ for i in xrange(10000):
++ fp.write(b"0"*50 + b"\n")
++ with open(self.filename, "rb") as f:
++ it = iter([1] + [0]*10) # one thread reads, others seek
++ def iterate():
++ if next(it):
++ for l in f:
++ pass
++ else:
++ for i in xrange(100):
++ f.seek(i*100, 0)
++ self._run_workers(iterate, 10)
++
+
+ @unittest.skipUnless(os.name == 'posix', 'test requires a posix system.')
+ class TestFileSignalEINTR(unittest.TestCase):
+--- a/Objects/fileobject.c 2018-02-16 17:49:45.304147750 -0500
++++ b/Objects/fileobject.c 2018-02-16 17:51:06.872149603 -0500
+@@ -430,7 +430,7 @@ close_the_file(PyFileObject *f)
+ if (f->ob_refcnt > 0) {
+ PyErr_SetString(PyExc_IOError,
+ "close() called during concurrent "
+- "operation on the same file object.");
++ "operation on the same file object");
+ } else {
+ /* This should not happen unless someone is
+ * carelessly playing with the PyFileObject
+@@ -438,7 +438,7 @@ close_the_file(PyFileObject *f)
+ * pointer. */
+ PyErr_SetString(PyExc_SystemError,
+ "PyFileObject locking error in "
+- "destructor (refcnt <= 0 at close).");
++ "destructor (refcnt <= 0 at close)");
+ }
+ return NULL;
+ }
+@@ -604,7 +604,12 @@ err_iterbuffered(void)
+ return NULL;
+ }
+
+-static void drop_readahead(PyFileObject *);
++static void
++drop_file_readahead(PyFileObject *f)
++{
++ PyMem_FREE(f->f_buf);
++ f->f_buf = NULL;
++}
+
+ /* Methods */
+
+@@ -627,7 +632,7 @@ file_dealloc(PyFileObject *f)
+ Py_XDECREF(f->f_mode);
+ Py_XDECREF(f->f_encoding);
+ Py_XDECREF(f->f_errors);
+- drop_readahead(f);
++ drop_file_readahead(f);
+ Py_TYPE(f)->tp_free((PyObject *)f);
+ }
+
+@@ -762,7 +767,7 @@ file_seek(PyFileObject *f, PyObject *arg
+
+ if (f->f_fp == NULL)
+ return err_closed();
+- drop_readahead(f);
++ drop_file_readahead(f);
+ whence = 0;
+ if (!PyArg_ParseTuple(args, "O|i:seek", &offobj, &whence))
+ return NULL;
+@@ -2221,12 +2226,16 @@ static PyGetSetDef file_getsetlist[] = {
+ {0},
+ };
+
++typedef struct {
++ char *buf, *bufptr, *bufend;
++} readaheadbuffer;
++
+ static void
+-drop_readahead(PyFileObject *f)
++drop_readaheadbuffer(readaheadbuffer *rab)
+ {
+- if (f->f_buf != NULL) {
+- PyMem_Free(f->f_buf);
+- f->f_buf = NULL;
++ if (rab->buf != NULL) {
++ PyMem_FREE(rab->buf);
++ rab->buf = NULL;
+ }
+ }
+
+@@ -2234,35 +2243,34 @@ drop_readahead(PyFileObject *f)
+ (unless at EOF) and no more than bufsize. Returns negative value on
+ error, will set MemoryError if bufsize bytes cannot be allocated. */
+ static int
+-readahead(PyFileObject *f, Py_ssize_t bufsize)
++readahead(PyFileObject *f, readaheadbuffer *rab, Py_ssize_t bufsize)
+ {
+ Py_ssize_t chunksize;
+
+- if (f->f_buf != NULL) {
+- if( (f->f_bufend - f->f_bufptr) >= 1)
++ if (rab->buf != NULL) {
++ if ((rab->bufend - rab->bufptr) >= 1)
+ return 0;
+ else
+- drop_readahead(f);
++ drop_readaheadbuffer(rab);
+ }
+- if ((f->f_buf = (char *)PyMem_Malloc(bufsize)) == NULL) {
++ if ((rab->buf = PyMem_MALLOC(bufsize)) == NULL) {
+ PyErr_NoMemory();
+ return -1;
+ }
+ FILE_BEGIN_ALLOW_THREADS(f)
+ errno = 0;
+- chunksize = Py_UniversalNewlineFread(
+- f->f_buf, bufsize, f->f_fp, (PyObject *)f);
++ chunksize = Py_UniversalNewlineFread(rab->buf, bufsize, f->f_fp, (PyObject *)f);
+ FILE_END_ALLOW_THREADS(f)
+ if (chunksize == 0) {
+ if (ferror(f->f_fp)) {
+ PyErr_SetFromErrno(PyExc_IOError);
+ clearerr(f->f_fp);
+- drop_readahead(f);
++ drop_readaheadbuffer(rab);
+ return -1;
+ }
+ }
+- f->f_bufptr = f->f_buf;
+- f->f_bufend = f->f_buf + chunksize;
++ rab->bufptr = rab->buf;
++ rab->bufend = rab->buf + chunksize;
+ return 0;
+ }
+
+@@ -2272,45 +2280,43 @@ readahead(PyFileObject *f, Py_ssize_t bu
+ logarithmic buffer growth to about 50 even when reading a 1gb line. */
+
+ static PyStringObject *
+-readahead_get_line_skip(PyFileObject *f, Py_ssize_t skip, Py_ssize_t bufsize)
++readahead_get_line_skip(PyFileObject *f, readaheadbuffer *rab, Py_ssize_t skip, Py_ssize_t bufsize)
+ {
+ PyStringObject* s;
+ char *bufptr;
+ char *buf;
+ Py_ssize_t len;
+
+- if (f->f_buf == NULL)
+- if (readahead(f, bufsize) < 0)
++ if (rab->buf == NULL)
++ if (readahead(f, rab, bufsize) < 0)
+ return NULL;
+
+- len = f->f_bufend - f->f_bufptr;
++ len = rab->bufend - rab->bufptr;
+ if (len == 0)
+- return (PyStringObject *)
+- PyString_FromStringAndSize(NULL, skip);
+- bufptr = (char *)memchr(f->f_bufptr, '\n', len);
++ return (PyStringObject *)PyString_FromStringAndSize(NULL, skip);
++ bufptr = (char *)memchr(rab->bufptr, '\n', len);
+ if (bufptr != NULL) {
+ bufptr++; /* Count the '\n' */
+- len = bufptr - f->f_bufptr;
+- s = (PyStringObject *)
+- PyString_FromStringAndSize(NULL, skip + len);
++ len = bufptr - rab->bufptr;
++ s = (PyStringObject *)PyString_FromStringAndSize(NULL, skip + len);
+ if (s == NULL)
+ return NULL;
+- memcpy(PyString_AS_STRING(s) + skip, f->f_bufptr, len);
+- f->f_bufptr = bufptr;
+- if (bufptr == f->f_bufend)
+- drop_readahead(f);
++ memcpy(PyString_AS_STRING(s) + skip, rab->bufptr, len);
++ rab->bufptr = bufptr;
++ if (bufptr == rab->bufend)
++ drop_readaheadbuffer(rab);
+ } else {
+- bufptr = f->f_bufptr;
+- buf = f->f_buf;
+- f->f_buf = NULL; /* Force new readahead buffer */
++ bufptr = rab->bufptr;
++ buf = rab->buf;
++ rab->buf = NULL; /* Force new readahead buffer */
+ assert(len <= PY_SSIZE_T_MAX - skip);
+- s = readahead_get_line_skip(f, skip + len, bufsize + (bufsize>>2));
++ s = readahead_get_line_skip(f, rab, skip + len, bufsize + (bufsize>>2));
+ if (s == NULL) {
+- PyMem_Free(buf);
++ PyMem_FREE(buf);
+ return NULL;
+ }
+ memcpy(PyString_AS_STRING(s) + skip, bufptr, len);
+- PyMem_Free(buf);
++ PyMem_FREE(buf);
+ }
+ return s;
+ }
+@@ -2328,7 +2334,30 @@ file_iternext(PyFileObject *f)
+ if (!f->readable)
+ return err_mode("reading");
+
+- l = readahead_get_line_skip(f, 0, READAHEAD_BUFSIZE);
++ {
++ /*
++ Multiple threads can enter this method while the GIL is released
++ during file read and wreak havoc on the file object's readahead
++ buffer. To avoid dealing with cross-thread coordination issues, we
++ cache the file buffer state locally and only set it back on the file
++ object when we're done.
++ */
++ readaheadbuffer rab = {f->f_buf, f->f_bufptr, f->f_bufend};
++ f->f_buf = NULL;
++ l = readahead_get_line_skip(f, &rab, 0, READAHEAD_BUFSIZE);
++ /*
++ Make sure the file's internal read buffer is cleared out. This will
++ only do anything if some other thread interleaved with us during
++ readahead. We want to drop any changeling buffer, so we don't leak
++ memory. We may lose data, but that's what you get for reading the same
++ file object in multiple threads.
++ */
++ drop_file_readahead(f);
++ f->f_buf = rab.buf;
++ f->f_bufptr = rab.bufptr;
++ f->f_bufend = rab.bufend;
++ }
++
+ if (l == NULL || PyString_GET_SIZE(l) == 0) {
+ Py_XDECREF(l);
+ return NULL;
+@@ -2692,7 +2721,7 @@ int PyObject_AsFileDescriptor(PyObject *
+ }
+ else {
+ PyErr_SetString(PyExc_TypeError,
+- "argument must be an int, or have a fileno() method.");
++ "argument must be an int, or have a fileno() method");
+ return -1;
+ }
development / ports / opt-arm.git / commitdiff