Issue #10350: Read and save errno before calling a function which might overwrite it.

Original patch by Hallvard B Furuseth.

1 files changed, 8 insertions, 5 deletions

diff --git a/Modules/readline.c b/Modules/readline.c
index a5e48ab..a710652 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -154,6 +154,7 @@ write_history_file(PyObject *self, PyObject *args)
 {
     PyObject *filename_obj = Py_None, *filename_bytes;
     char *filename;
+    int err;
     if (!PyArg_ParseTuple(args, "|O:write_history_file", &filename_obj))
         return NULL;
     if (filename_obj != Py_None) {
@@ -164,10 +165,11 @@ write_history_file(PyObject *self, PyObject *args)
         filename_bytes = NULL;
         filename = NULL;
     }
-    errno = write_history(filename);
-    if (!errno && _history_length >= 0)
+    errno = err = write_history(filename);
+    if (!err && _history_length >= 0)
         history_truncate_file(filename, _history_length);
     Py_XDECREF(filename_bytes);
+    errno = err;
     if (errno)
         return PyErr_SetFromErrno(PyExc_IOError);
     Py_RETURN_NONE;
@@ -969,7 +971,7 @@ readline_until_enter_or_signal(char *prompt, int *signal)
     completed_input_string = not_done_reading;
 
     while (completed_input_string == not_done_reading) {
-        int has_input = 0;
+        int has_input = 0, err = 0;
 
         while (!has_input)
         {               struct timeval timeout = {0, 100000}; /* 0.1 seconds */
@@ -983,13 +985,14 @@ readline_until_enter_or_signal(char *prompt, int *signal)
             /* select resets selectset if no input was available */
             has_input = select(fileno(rl_instream) + 1, &selectset,
                                NULL, NULL, timeoutp);
+            err = errno;
             if(PyOS_InputHook) PyOS_InputHook();
         }
 
-        if(has_input > 0) {
+        if (has_input > 0) {
             rl_callback_read_char();
         }
-        else if (errno == EINTR) {
+        else if (err == EINTR) {
             int s;
 #ifdef WITH_THREAD
             PyEval_RestoreThread(_PyOS_ReadlineTState);