Jonathan Giddy writes:
Here's a patch to fix the race condition, which wasn't fixed by Rob's
patch. It holds the gethostbyname lock until the results are copied out,
which means that this lock and the Python global lock are held at the same
time. This shouldn't be a problem as long as the gethostbyname lock is
always acquired when the global lock is not held.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 8b087d2..da1d223 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -328,6 +328,7 @@
{
struct hostent *hp;
int d1, d2, d3, d4;
+ int h_length;
char ch;
#ifdef HAVE_GETHOSTBYNAME_R
struct hostent hp_allocated;
@@ -368,9 +369,6 @@
PyThread_acquire_lock(gethostbyname_lock,1);
#endif
hp = gethostbyname(name);
-#if defined(WITH_THREAD) && !defined(MS_WINDOWS)
- PyThread_release_lock(gethostbyname_lock);
-#endif
#endif /* HAVE_GETHOSTBYNAME_R */
Py_END_ALLOW_THREADS
@@ -382,10 +380,17 @@
#else
PyErr_SetString(PySocket_Error, "host not found");
#endif
+#if defined(WITH_THREAD) && !defined(HAVE_GETHOSTBYNAME_R) && !defined(MS_WINDOWS)
+ PyThread_release_lock(gethostbyname_lock);
+#endif
return -1;
}
memcpy((char *) &addr_ret->sin_addr, hp->h_addr, hp->h_length);
- return hp->h_length;
+ h_length = hp->h_length;
+#if defined(WITH_THREAD) && !defined(HAVE_GETHOSTBYNAME_R) && !defined(MS_WINDOWS)
+ PyThread_release_lock(gethostbyname_lock);
+#endif
+ return h_length;
}
@@ -1409,6 +1414,7 @@
char *name;
struct hostent *h;
struct sockaddr_in addr;
+ PyObject *ret;
#ifdef HAVE_GETHOSTBYNAME_R
struct hostent hp_allocated;
char buf[16384];
@@ -1434,12 +1440,13 @@
PyThread_acquire_lock(gethostbyname_lock,1);
#endif
h = gethostbyname(name);
-#if defined(WITH_THREAD) && !defined(MS_WINDOWS)
- PyThread_release_lock(gethostbyname_lock);
-#endif
#endif /* HAVE_GETHOSTBYNAME_R */
Py_END_ALLOW_THREADS
- return gethost_common(h,&addr);
+ ret = gethost_common(h,&addr);
+#if defined(WITH_THREAD) && !defined(HAVE_GETHOSTBYNAME_R) && !defined(MS_WINDOWS)
+ PyThread_release_lock(gethostbyname_lock);
+#endif
+ return ret;
}
static char ghbn_ex_doc[] =