diff -r 0acc5626a578 Modules/_cursesmodule.c
--- a/Modules/_cursesmodule.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/_cursesmodule.c	Sat Dec 08 01:17:17 2012 +0100
@@ -1713,7 +1713,11 @@
         remove(fn);
         return res;
     }
-    fseek(fp, 0, 0);
+    if (fseek(fp, 0, 0) == -1) {
+        fclose(fp);
+        remove(fn);
+        return PyErr_SetFromErrnoWithFilename(PyExc_IOError, fn);
+    }
     while (1) {
         char buf[BUFSIZ];
         Py_ssize_t n = fread(buf, 1, BUFSIZ, fp);
@@ -2293,7 +2297,11 @@
         return PyErr_SetFromErrnoWithFilename(PyExc_IOError, fn);
     }
     Py_DECREF(data);
-    fseek(fp, 0, 0);
+    if (fseek(fp, 0, 0) == -1) {
+        fclose(fp);
+        remove(fn);
+        return PyErr_SetFromErrnoWithFilename(PyExc_IOError, fn);
+    }
     win = getwin(fp);
     fclose(fp);
     remove(fn);
diff -r 0acc5626a578 Modules/_posixsubprocess.c
--- a/Modules/_posixsubprocess.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/_posixsubprocess.c	Sat Dec 08 01:17:17 2012 +0100
@@ -321,7 +321,10 @@
             /* readdir error, revert behavior. Highly Unlikely. */
             _close_fds_by_brute_force(start_fd, end_fd, py_fds_to_keep);
         }
-        closedir(proc_fd_dir);
+        if (closedir(proc_fd_dir) == -1) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return; 
+        }
     }
 }
 
diff -r 0acc5626a578 Modules/faulthandler.c
--- a/Modules/faulthandler.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/faulthandler.c	Sat Dec 08 01:17:17 2012 +0100
@@ -445,7 +445,10 @@
         /* get the thread holding the GIL, NULL if no thread hold the GIL */
         current = _Py_atomic_load_relaxed(&_PyThreadState_Current);
 
-        write(thread.fd, thread.header, thread.header_len);
+        if (write(thread.fd, thread.header, thread.header_len) == -1) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return; 
+        }
 
         errmsg = _Py_DumpTracebackThreads(thread.fd, thread.interp, current);
         ok = (errmsg == NULL);
diff -r 0acc5626a578 Modules/getpath.c
--- a/Modules/getpath.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/getpath.c	Sat Dec 08 01:17:17 2012 +0100
@@ -271,7 +271,10 @@
     int result = 0; /* meaning not found */
     char buffer[MAXPATHLEN*2+1];  /* allow extra for key, '=', etc. */
 
-    fseek(env_file, 0, SEEK_SET);
+    if (fseek(env_file, 0, SEEK_SET) == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return result;
+    }
     while (!feof(env_file)) {
         char * p = fgets(buffer, MAXPATHLEN*2, env_file);
         wchar_t tmpbuffer[MAXPATHLEN*2+1];
diff -r 0acc5626a578 Modules/mmapmodule.c
--- a/Modules/mmapmodule.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/mmapmodule.c	Sat Dec 08 01:17:17 2012 +0100
@@ -1322,7 +1322,10 @@
             return NULL;
         }
         /* Win9x appears to need us seeked to zero */
-        lseek(fileno, 0, SEEK_SET);
+        if (lseek(fileno, 0, SEEK_SET) < 0) {
+            PyErr_SetFromErrno(PyExc_OSError);
+            return NULL;
+        }
     }
 
     m_obj = (mmap_object *)type->tp_alloc(type, 0);
diff -r 0acc5626a578 Modules/posixmodule.c
--- a/Modules/posixmodule.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/posixmodule.c	Sat Dec 08 01:17:17 2012 +0100
@@ -3428,7 +3428,10 @@
         Py_BEGIN_ALLOW_THREADS
         if (fd > -1)
             rewinddir(dirp);
-        closedir(dirp);
+        if (closedir(dirp) == -1) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return list; 
+        }
         Py_END_ALLOW_THREADS
     }
 
@@ -5568,10 +5571,19 @@
     if (slave_fd < 0)
         return posix_error();
 #if !defined(__CYGWIN__) && !defined(HAVE_DEV_PTC)
-    ioctl(slave_fd, I_PUSH, "ptem"); /* push ptem */
-    ioctl(slave_fd, I_PUSH, "ldterm"); /* push ldterm */
+    if (ioctl(slave_fd, I_PUSH, "ptem") == -1) { /* push ptem */
+        PyErr_SetFromErrno(PyExc_IOError);
+        return posix_error(); 
+    }
+    if (ioctl(slave_fd, I_PUSH, "ldterm") == -1) { /* push ldterm */
+        PyErr_SetFromErrno(PyExc_IOError);
+        return posix_error(); 
+    }
 #ifndef __hpux
-    ioctl(slave_fd, I_PUSH, "ttcompat"); /* push ttcompat */
+    if (ioctl(slave_fd, I_PUSH, "ttcompat") == -1) { /* push ttcompat */
+        PyErr_SetFromErrno(PyExc_IOError);
+        return posix_error(); 
+    }
 #endif /* __hpux */
 #endif /* HAVE_CYGWIN */
 #endif /* HAVE_OPENPTY */
diff -r 0acc5626a578 Modules/signalmodule.c
--- a/Modules/signalmodule.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/signalmodule.c	Sat Dec 08 01:17:17 2012 +0100
@@ -180,7 +180,10 @@
     Handlers[sig_num].tripped = 1;
     if (wakeup_fd != -1) {
         byte = (unsigned char)sig_num;
-        write(wakeup_fd, &byte, 1);
+        if (write(wakeup_fd, &byte, 1) == -1) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return;
+        }
     }
     if (is_tripped)
         return;
diff -r 0acc5626a578 Modules/socketmodule.c
--- a/Modules/socketmodule.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Modules/socketmodule.c	Sat Dec 08 01:17:17 2012 +0100
@@ -607,14 +607,20 @@
 #ifndef MS_WINDOWS
 #if defined(__VMS)
     block = !block;
-    ioctl(s->sock_fd, FIONBIO, (unsigned int *)&block);
+    if (ioctl(s->sock_fd, FIONBIO, (unsigned int *)&block) == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return 1; 
+    }
 #else  /* !__VMS */
     delay_flag = fcntl(s->sock_fd, F_GETFL, 0);
     if (block)
         delay_flag &= (~O_NONBLOCK);
     else
         delay_flag |= O_NONBLOCK;
-    fcntl(s->sock_fd, F_SETFL, delay_flag);
+    if (fcntl(s->sock_fd, F_SETFL, delay_flag) == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return 1; 
+    }
 #endif /* !__VMS */
 #else /* MS_WINDOWS */
     block = !block;
diff -r 0acc5626a578 Python/marshal.c
--- a/Python/marshal.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Python/marshal.c	Sat Dec 08 01:17:17 2012 +0100
@@ -98,7 +98,10 @@
 w_string(char *s, int n, WFILE *p)
 {
     if (p->fp != NULL) {
-        fwrite(s, 1, n, p->fp);
+        if (fwrite(s, 1, n, p->fp) == -1) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return;
+        }
     }
     else {
         while (--n >= 0) {
diff -r 0acc5626a578 Python/traceback.c
--- a/Python/traceback.c	Tue Oct 23 22:50:11 2012 +0100
+++ b/Python/traceback.c	Sat Dec 08 01:17:17 2012 +0100
@@ -257,7 +257,10 @@
     fd = PyObject_AsFileDescriptor(binary);
     found_encoding = PyTokenizer_FindEncodingFilename(fd, filename);
     encoding = (found_encoding != NULL) ? found_encoding : "utf-8";
-    lseek(fd, 0, 0); /* Reset position */
+    if (lseek(fd, 0, 0) == -1) { /* Reset position */
+        PyErr_SetFromErrno(PyExc_IOError);
+        return -1;
+    }
     fob = _PyObject_CallMethodId(io, &PyId_TextIOWrapper, "Os", binary, encoding);
     Py_DECREF(io);
     Py_DECREF(binary);
@@ -455,7 +458,10 @@
         len++;
     } while (value);
     reverse_string(buffer, len);
-    write(fd, buffer, len);
+    if (write(fd, buffer, len) == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return;
+    }
 }
 
 /* Format an integer in range [0; 0xffffffff] to hexdecimal of 'width' digits,
@@ -475,7 +481,11 @@
         len++;
     } while (len < width || value);
     reverse_string(buffer, len);
-    write(fd, buffer, len);
+    if (write(fd, buffer, len) == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return;
+    }
+
 }
 
 /* Write an unicode object into the file fd using ascii+backslashreplace.
@@ -527,7 +537,11 @@
             ch = wstr[i];
         if (ch < 128) {
             char c = (char)ch;
-            write(fd, &c, 1);
+            if (write(fd, &c, 1) == -1) {
+                PyErr_SetFromErrno(PyExc_IOError);
+                return;
+            }
+
         }
         else if (ch < 0xff) {
             PUTS(fd, "\\x");
@@ -561,9 +575,17 @@
     if (code != NULL && code->co_filename != NULL
         && PyUnicode_Check(code->co_filename))
     {
-        write(fd, "\"", 1);
+        if (write(fd, "\"", 1)) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return;
+        }
+
         dump_ascii(fd, code->co_filename);
-        write(fd, "\"", 1);
+
+        if (write(fd, "\"", 1)) {
+            PyErr_SetFromErrno(PyExc_IOError);
+            return;
+        }
     } else {
         PUTS(fd, "???");
     }
@@ -580,7 +602,10 @@
     else
         PUTS(fd, "???");
 
-    write(fd, "\n", 1);
+    if (write(fd, "\n", 1)) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return;
+    }
 }
 
 static void
@@ -649,8 +674,13 @@
     nthreads = 0;
     do
     {
-        if (nthreads != 0)
-            write(fd, "\n", 1);
+        if (nthreads != 0) {
+            if (write(fd, "\"", 1) == -1) {
+                PyErr_SetFromErrno(PyExc_IOError);
+                return;
+            }
+        }
+            
         if (nthreads >= MAX_NTHREADS) {
             PUTS(fd, "...\n");
             break;