Fixes issue #12268: File readline, readlines and read() or readall() methods

no longer lose data when an underlying read system call is interrupted.
IOError is no longer raised due to a read system call returning EINTR
from within these methods.

Misc/NEWS

@@ -10,6 +10,11 @@ What's New in Python 3.2.4
 Core and Builtins
 -----------------
 
+- Issue #12268: File readline, readlines and read() or readall() methods
+  no longer lose data when an underlying read system call is interrupted.
+  IOError is no longer raised due to a read system call returning EINTR
+  from within these methods.
+
 - Issue #15142: Fix reference leak when deallocating instances of types
   created using PyType_FromSpec().
 

Modules/_io/_iomodule.h

@@ -57,6 +57,11 @@ extern Py_ssize_t _PyIO_find_line_ending(
     int translated, int universal, PyObject *readnl,
     Py_UNICODE *start, Py_UNICODE *end, Py_ssize_t *consumed);
 
+/* Return 1 if an EnvironmentError with errno == EINTR is set (and then
+   clears the error indicator), 0 otherwise.
+   Should only be called when PyErr_Occurred() is true.
+*/
+extern int _PyIO_trap_eintr(void);
 
 #define DEFAULT_BUFFER_SIZE (8 * 1024)  /* bytes */
 

Modules/_io/bufferedio.c

@@ -730,8 +730,8 @@ _buffered_init(buffered *self)
    clears the error indicator), 0 otherwise.
    Should only be called when PyErr_Occurred() is true.
 */
-static int
-_trap_eintr(void)
+int
+_PyIO_trap_eintr(void)
 {
     static PyObject *eintr_int = NULL;
     PyObject *typ, *val, *tb;
@@ -1314,7 +1314,7 @@ _bufferedreader_raw_read(buffered *self, char *start, Py_ssize_t len)
     */
     do {
         res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_readinto, memobj, NULL);
-    } while (res == NULL && _trap_eintr());
+    } while (res == NULL && _PyIO_trap_eintr());
     Py_DECREF(memobj);
     if (res == NULL)
         return -1;
@@ -1742,7 +1742,7 @@ _bufferedwriter_raw_write(buffered *self, char *start, Py_ssize_t len)
         errno = 0;
         res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_write, memobj, NULL);
         errnum = errno;
-    } while (res == NULL && _trap_eintr());
+    } while (res == NULL && _PyIO_trap_eintr());
     Py_DECREF(memobj);
     if (res == NULL)
         return -1;

Modules/_io/fileio.c

@@ -605,6 +605,13 @@ fileio_readall(fileio *self)
         if (n == 0)
             break;
         if (n < 0) {
+            if (errno == EINTR) {
+                if (PyErr_CheckSignals()) {
+                    Py_DECREF(result);
+                    return NULL;
+                }
+                continue;
+            }
             if (total > 0)
                 break;
             if (errno == EAGAIN) {

Modules/_io/iobase.c

@@ -482,8 +482,14 @@ iobase_readline(PyObject *self, PyObject *args)
 
         if (has_peek) {
             PyObject *readahead = PyObject_CallMethod(self, "peek", "i", 1);
-            if (readahead == NULL)
+            if (readahead == NULL) {
+                /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
+                   when EINTR occurs so we needn't do it ourselves. */
+                if (_PyIO_trap_eintr()) {
+                    continue;
+                }
                 goto fail;
+            }
             if (!PyBytes_Check(readahead)) {
                 PyErr_Format(PyExc_IOError,
                              "peek() should have returned a bytes object, "
@@ -516,8 +522,14 @@ iobase_readline(PyObject *self, PyObject *args)
         }
 
         b = PyObject_CallMethod(self, "read", "n", nreadahead);
-        if (b == NULL)
+        if (b == NULL) {
+            /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
+               when EINTR occurs so we needn't do it ourselves. */
+            if (_PyIO_trap_eintr()) {
+                continue;
+            }
             goto fail;
+        }
         if (!PyBytes_Check(b)) {
             PyErr_Format(PyExc_IOError,
                          "read() should have returned a bytes object, "
@@ -826,6 +838,11 @@ rawiobase_readall(PyObject *self, PyObject *args)
         PyObject *data = PyObject_CallMethod(self, "read",
                                              "i", DEFAULT_BUFFER_SIZE);
         if (!data) {
+            /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
+               when EINTR occurs so we needn't do it ourselves. */
+            if (_PyIO_trap_eintr()) {
+                continue;
+            }
             Py_DECREF(chunks);
             return NULL;
         }

Modules/_io/textio.c

@@ -1541,8 +1541,14 @@ textiowrapper_read(textio *self, PyObject *args)
         /* Keep reading chunks until we have n characters to return */
         while (remaining > 0) {
             res = textiowrapper_read_chunk(self);
-            if (res < 0)
+            if (res < 0) {
+                /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
+                   when EINTR occurs so we needn't do it ourselves. */
+                if (_PyIO_trap_eintr()) {
+                    continue;
+                }
                 goto fail;
+            }
             if (res == 0)  /* EOF */
                 break;
             if (chunks == NULL) {
@@ -1701,8 +1707,14 @@ _textiowrapper_readline(textio *self, Py_ssize_t limit)
         while (!self->decoded_chars ||
                !PyUnicode_GET_SIZE(self->decoded_chars)) {
             res = textiowrapper_read_chunk(self);
-            if (res < 0)
+            if (res < 0) {
+                /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
+                   when EINTR occurs so we needn't do it ourselves. */
+                if (_PyIO_trap_eintr()) {
+                    continue;
+                }
                 goto error;
+            }
             if (res == 0)
                 break;
         }