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.

5 files changed, 49 insertions, 10 deletions

diff --git a/Modules/_io/_iomodule.h b/Modules/_io/_iomodule.h
index 987aac8..0fe90a3 100644
--- a/Modules/_io/_iomodule.h
+++ b/Modules/_io/_iomodule.h
@@ -57,6 +57,11 @@ extern Py_ssize_t _PyIO_find_line_ending(
     int translated, int universal, PyObject *readnl,
     int kind, char *start, char *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 */
 
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index dc723b1..21393a3 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -746,8 +746,8 @@ _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;
@@ -1396,7 +1396,7 @@ _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;
@@ -1850,7 +1850,7 @@ _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;
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 226a5d2..198392f 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -670,6 +670,13 @@ 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) {
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index b30bbb6..dd052ae 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -474,11 +474,15 @@ iobase_readline(PyObject *self, PyObject *args)
         PyObject *b;
 
         if (has_peek) {
-            _Py_IDENTIFIER(peek);
             PyObject *readahead = _PyObject_CallMethodId(self, &PyId_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, "
@@ -511,8 +515,14 @@ iobase_readline(PyObject *self, PyObject *args)
         }
 
         b = _PyObject_CallMethodId(self, &PyId_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, "
@@ -827,6 +837,11 @@ rawiobase_readall(PyObject *self, PyObject *args)
         PyObject *data = _PyObject_CallMethodId(self, &PyId_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;
         }
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 287f165..d390d5a 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -1560,8 +1560,14 @@ textiowrapper_read(textio *self, PyObject *args)
         /* Keep reading chunks until we have n characters to return */
         while (remaining > 0) {
             res = textiowrapper_read_chunk(self, remaining);
-            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) {
@@ -1728,8 +1734,14 @@ _textiowrapper_readline(textio *self, Py_ssize_t limit)
         while (!self->decoded_chars ||
                !PyUnicode_GET_LENGTH(self->decoded_chars)) {
             res = textiowrapper_read_chunk(self, 0);
-            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;
         }