Merge branch 'writev-max-num-vectors' into 'master'

Clamp number of vectors to IOV_MAX / UIO_MAXIOV for GOutputStream writev()...

See merge request GNOME/glib!874

gio/gioprivate.h

@@ -35,6 +35,23 @@ gboolean g_output_stream_async_close_is_via_threads (GOutputStream *stream);
 void g_socket_connection_set_cached_remote_address (GSocketConnection *connection,
                                                     GSocketAddress    *address);
 
+/* POSIX defines IOV_MAX/UIO_MAXIOV as the maximum number of iovecs that can
+ * be sent in one go. We define our own version of it here as there are two
+ * possible names, and also define a fall-back value if none of the constants
+ * are defined */
+#if defined(IOV_MAX)
+#define G_IOV_MAX IOV_MAX
+#elif defined(UIO_MAXIOV)
+#define G_IOV_MAX UIO_MAXIOV
+#else
+/* 16 is the minimum value required by POSIX */
+#define G_IOV_MAX 16
+#endif
+
+/* The various functions taking iovecs as parameter use a plain int
+ * for the number of vectors. Limit it to G_MAXINT for this reason.
+ */
+G_STATIC_ASSERT (G_IOV_MAX <= G_MAXINT);
 
 G_END_DECLS
 

gio/glocalfileoutputstream.c

@@ -42,6 +42,7 @@
 #endif
 
 #include "glib-private.h"
+#include "gioprivate.h"
 
 #ifdef G_OS_WIN32
 #include <io.h>
@@ -243,11 +244,11 @@ g_local_file_output_stream_writev (GOutputStream        *stream,
   if (bytes_written)
     *bytes_written = 0;
 
-  /* Clamp to G_MAXINT as writev() takes an integer for the number of vectors.
+  /* Clamp the number of vectors if more given than we can write in one go.
-   * We handle this like a short write in this case
+   * The caller has to handle short writes anyway.
    */
-  if (n_vectors > G_MAXINT)
+  if (n_vectors > G_IOV_MAX)
-    n_vectors = G_MAXINT;
+    n_vectors = G_IOV_MAX;
 
   file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
 

gio/gsocket.c

@@ -74,6 +74,7 @@
 #include "gcredentials.h"
 #include "gcredentialsprivate.h"
 #include "glibintl.h"
+#include "gioprivate.h"
 
 #ifdef G_OS_WIN32
 /* For Windows XP runtime compatibility, but use the system's if_nametoindex() if available */
@@ -4960,14 +4961,11 @@ g_socket_send_messages_with_timeout (GSocket        *socket,
     struct mmsghdr *msgvec;
     gint i, num_sent;
 
-#ifdef UIO_MAXIOV
+    /* Clamp the number of vectors if more given than we can write in one go.
-#define MAX_NUM_MESSAGES UIO_MAXIOV
+     * The caller has to handle short writes anyway.
-#else
+     */
-#define MAX_NUM_MESSAGES 1024
+    if (num_messages > G_IOV_MAX)
-#endif
+      num_messages = G_IOV_MAX;
-
-    if (num_messages > MAX_NUM_MESSAGES)
-      num_messages = MAX_NUM_MESSAGES;
 
     msgvec = g_newa (struct mmsghdr, num_messages);
 
@@ -5482,14 +5480,11 @@ g_socket_receive_messages_with_timeout (GSocket        *socket,
     struct mmsghdr *msgvec;
     guint i, num_received;
 
-#ifdef UIO_MAXIOV
+    /* Clamp the number of vectors if more given than we can write in one go.
-#define MAX_NUM_MESSAGES UIO_MAXIOV
+     * The caller has to handle short writes anyway.
-#else
+     */
-#define MAX_NUM_MESSAGES 1024
+    if (num_messages > G_IOV_MAX)
-#endif
+      num_messages = G_IOV_MAX;
-
-    if (num_messages > MAX_NUM_MESSAGES)
-      num_messages = MAX_NUM_MESSAGES;
 
     msgvec = g_newa (struct mmsghdr, num_messages);
 

gio/gsocketoutputstream.c

@@ -33,6 +33,7 @@
 #include "gioerror.h"
 #include "glibintl.h"
 #include "gfiledescriptorbased.h"
+#include "gioprivate.h"
 
 struct _GSocketOutputStreamPrivate
 {
@@ -146,8 +147,8 @@ g_socket_output_stream_writev (GOutputStream        *stream,
   /* Clamp the number of vectors if more given than we can write in one go.
    * The caller has to handle short writes anyway.
    */
-  if (n_vectors > G_MAXINT)
+  if (n_vectors > G_IOV_MAX)
-    n_vectors = G_MAXINT;
+    n_vectors = G_IOV_MAX;
 
   res = g_socket_send_message_with_timeout (output_stream->priv->socket, NULL,
                                             vectors, n_vectors,
@@ -194,8 +195,8 @@ g_socket_output_stream_pollable_writev_nonblocking (GPollableOutputStream  *poll
   /* Clamp the number of vectors if more given than we can write in one go.
    * The caller has to handle short writes anyway.
    */
-  if (n_vectors > G_MAXINT)
+  if (n_vectors > G_IOV_MAX)
-    n_vectors = G_MAXINT;
+    n_vectors = G_IOV_MAX;
 
   return g_socket_send_message_with_timeout (output_stream->priv->socket,
                                              NULL, vectors, n_vectors,

gio/gunixoutputstream.c

@@ -37,6 +37,7 @@
 #include "gasynchelper.h"
 #include "gfiledescriptorbased.h"
 #include "glibintl.h"
+#include "gioprivate.h"
 
 
 /**
@@ -425,11 +426,11 @@ g_unix_output_stream_writev (GOutputStream        *stream,
   if (bytes_written)
     *bytes_written = 0;
 
-  /* Clamp to G_MAXINT as writev() takes an integer for the number of vectors.
+  /* Clamp the number of vectors if more given than we can write in one go.
-   * We handle this like a short write in this case
+   * The caller has to handle short writes anyway.
    */
-  if (n_vectors > G_MAXINT)
+  if (n_vectors > G_IOV_MAX)
-    n_vectors = G_MAXINT;
+    n_vectors = G_IOV_MAX;
 
   unix_stream = G_UNIX_OUTPUT_STREAM (stream);
 
@@ -635,11 +636,11 @@ g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream  *stream
       return G_POLLABLE_RETURN_WOULD_BLOCK;
     }
 
-  /* Clamp to G_MAXINT as writev() takes an integer for the number of vectors.
+  /* Clamp the number of vectors if more given than we can write in one go.
-   * We handle this like a short write in this case
+   * The caller has to handle short writes anyway.
    */
-  if (n_vectors > G_MAXINT)
+  if (n_vectors > G_IOV_MAX)
-    n_vectors = G_MAXINT;
+    n_vectors = G_IOV_MAX;
 
   if (G_OUTPUT_VECTOR_IS_IOVEC)
     {