r7211: - use ioctl(FIONREAD) to remove the artificial limit on messaging size

- avoid a memcpy
(This used to be commit 753839c358f45c02927b137092828f3a79158083)

diff --git a/source4/lib/messaging/messaging.c b/source4/lib/messaging/messaging.c
index 4d2cd9c91071b4a92b503299573fc81d9177ad5e..eb526fd39113e232ac480eeb642454bd61a1f82b 100644 (file)
--- a/source4/lib/messaging/messaging.c
+++ b/source4/lib/messaging/messaging.c
@@ -31,9 +31,6 @@
 /* change the message version with any incompatible changes in the protocol */
 #define MESSAGING_VERSION 1
 
-/* maximum message size */
-#define MESSAGING_MAX_SIZE 512
-
 struct messaging_context {
        uint32_t server_id;
        struct socket_context *sock;
@@ -63,15 +60,15 @@ struct messaging_rec {
        struct messaging_context *msg;
        const char *path;
 
-       struct {
+       struct messaging_header {
                uint32_t version;
                uint32_t msg_type;
                uint32_t from;
                uint32_t to;
                uint32_t length;
-       } header;
+       } *header;
 
-       DATA_BLOB data;
+       DATA_BLOB packet;
 };
 
 
@@ -106,11 +103,14 @@ static void messaging_dispatch(struct messaging_context *msg, struct messaging_r
        struct dispatch_fn *d, *next;
        for (d=msg->dispatch;d;d=next) {
                next = d->next;
-               if (d->msg_type == rec->header.msg_type) {
-                       d->fn(msg, d->private, d->msg_type, rec->header.from, &rec->data);
+               if (d->msg_type == rec->header->msg_type) {
+                       DATA_BLOB data;
+                       data.data = rec->packet.data + sizeof(*rec->header);
+                       data.length = rec->header->length;
+                       d->fn(msg, d->private, d->msg_type, rec->header->from, &data);
                }
        }
-       rec->header.length = 0;
+       rec->header->length = 0;
 }
 
 
@@ -120,24 +120,15 @@ static void messaging_dispatch(struct messaging_context *msg, struct messaging_r
 static NTSTATUS try_send(struct messaging_rec *rec)
 {
        struct messaging_context *msg = rec->msg;
-       DATA_BLOB blob;
        size_t nsent;
        void *priv;
        NTSTATUS status;
 
-       blob = data_blob_talloc(rec, NULL, sizeof(rec->header) + rec->data.length);
-       NT_STATUS_HAVE_NO_MEMORY(blob.data);
-
-       memcpy(blob.data, &rec->header, sizeof(rec->header));
-       memcpy(blob.data + sizeof(rec->header), rec->data.data, rec->data.length);
-
        /* we send with privileges so messages work from any context */
        priv = root_privileges();
-       status = socket_sendto(msg->sock, &blob, &nsent, 0, rec->path, 0);
+       status = socket_sendto(msg->sock, &rec->packet, &nsent, 0, rec->path, 0);
        talloc_free(priv);
 
-       data_blob_free(&blob);
-
        return status;
 }
 
@@ -155,7 +146,7 @@ static void messaging_send_handler(struct messaging_context *msg)
                }
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(1,("messaging: Lost message from %u to %u of type %u - %s\n", 
-                                rec->header.from, rec->header.to, rec->header.msg_type, 
+                                rec->header->from, rec->header->to, rec->header->msg_type, 
                                 nt_errstr(status)));
                }
                DLIST_REMOVE(msg->pending, rec);
@@ -173,16 +164,31 @@ static void messaging_recv_handler(struct messaging_context *msg)
 {
        struct messaging_rec *rec;
        NTSTATUS status;
-       uint8_t data[MESSAGING_MAX_SIZE];
+       DATA_BLOB packet;
        size_t msize;
+       int dsize=0;
 
-       status = socket_recv(msg->sock, data, sizeof(data), &msize, 0);
+       /* see how many bytes are in the next packet */
+       if (ioctl(socket_get_fd(msg->sock), FIONREAD, &dsize) != 0) {
+               DEBUG(0,("FIONREAD failed in messaging - %s\n", strerror(errno)));
+               return;
+       }
+       
+       packet = data_blob_talloc(msg, NULL, dsize);
+       if (packet.data == NULL) {
+               /* assume this is temporary and retry */
+               return;
+       }
+           
+       status = socket_recv(msg->sock, packet.data, dsize, &msize, 0);
        if (!NT_STATUS_IS_OK(status)) {
+               data_blob_free(&packet);
                return;
        }
 
-       if (msize < sizeof(rec->header)) {
+       if (msize < sizeof(*rec->header)) {
                DEBUG(0,("messaging: bad message of size %d\n", msize));
+               data_blob_free(&packet);
                return;
        }
 
@@ -191,19 +197,15 @@ static void messaging_recv_handler(struct messaging_context *msg)
                smb_panic("Unable to allocate messaging_rec");
        }
 
+       talloc_steal(rec, packet.data);
        rec->msg           = msg;
        rec->path          = msg->path;
+       rec->header        = (struct messaging_header *)packet.data;
+       rec->packet        = packet;
 
-       memcpy(&rec->header, data, sizeof(rec->header));
-       if (msize != sizeof(rec->header) + rec->header.length) {
+       if (msize != sizeof(*rec->header) + rec->header->length) {
                DEBUG(0,("messaging: bad message header size %d should be %d\n", 
-                        rec->header.length, msize - sizeof(rec->header)));
-               talloc_free(rec);
-               return;
-       }
-
-       rec->data = data_blob_talloc(rec, data+sizeof(rec->header), rec->header.length);
-       if (rec->data.data == NULL) {
+                        rec->header->length, msize - sizeof(*rec->header)));
                talloc_free(rec);
                return;
        }
@@ -272,22 +274,29 @@ NTSTATUS messaging_send(struct messaging_context *msg, uint32_t server,
 {
        struct messaging_rec *rec;
        NTSTATUS status;
+       size_t dlength = data?data->length:0;
 
        rec = talloc(msg, struct messaging_rec);
        if (rec == NULL) {
                return NT_STATUS_NO_MEMORY;
        }
 
-       rec->msg             = msg;
-       rec->header.version  = MESSAGING_VERSION;
-       rec->header.msg_type = msg_type;
-       rec->header.from     = msg->server_id;
-       rec->header.to       = server;
-       rec->header.length   = data?data->length:0;
-       if (rec->header.length != 0) {
-               rec->data = data_blob_talloc(rec, data->data, data->length);
-       } else {
-               rec->data = data_blob(NULL, 0);
+       rec->packet = data_blob_talloc(rec, NULL, sizeof(*rec->header) + dlength);
+       if (rec->packet.data == NULL) {
+               talloc_free(rec);
+               return NT_STATUS_NO_MEMORY;
+       }
+
+       rec->msg              = msg;
+       rec->header           = (struct messaging_header *)rec->packet.data;
+       rec->header->version  = MESSAGING_VERSION;
+       rec->header->msg_type = msg_type;
+       rec->header->from     = msg->server_id;
+       rec->header->to       = server;
+       rec->header->length   = dlength;
+       if (dlength != 0) {
+               memcpy(rec->packet.data + sizeof(*rec->header), 
+                      data->data, dlength);
        }
 
        rec->path = messaging_path(rec, server);