Add a way to set the channel's priv pointer when opening it.

This prevents a race condition where between opening a channel and
setting the priv pointer, the receive callback is called.

diff --git a/src/meshlink++.h b/src/meshlink++.h
index f5921363e0dffa550a5a38065bc8eaafc703829f..64673f58cb42dc119ef9eea30e6d2d67826a9b8b 100644 (file)
--- a/src/meshlink++.h
+++ b/src/meshlink++.h
@@ -732,6 +732,7 @@ public:
         *  @param cb           A pointer to the function which will be called when the remote node sends data to the local node.
         *  @param data         A pointer to a buffer containing data to already queue for sending.
         *  @param len          The length of the data.
+        *                      If len is 0, the data pointer is copied into the channel's priv member.
         *  @param flags        A bitwise-or'd combination of flags that set the semantics for this channel.
         *
         *  @return             A handle for the channel, or NULL in case of an error.
@@ -756,6 +757,7 @@ public:
         *  @param port         The port number the peer wishes to connect to.
         *  @param data         A pointer to a buffer containing data to already queue for sending.
         *  @param len          The length of the data.
+        *                      If len is 0, the data pointer is copied into the channel's priv member.
         *  @param flags        A bitwise-or'd combination of flags that set the semantics for this channel.
         *
         *  @return             A handle for the channel, or NULL in case of an error.

diff --git a/src/meshlink.c b/src/meshlink.c
index e82ea4f11a384f639f3c6298a42bfa15aecf3e8a..f1b6a334c6a7bb90bd6be8018a90b861a65a2842 100644 (file)
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -3150,7 +3150,7 @@ void meshlink_set_channel_rcvbuf(meshlink_handle_t *mesh, meshlink_channel_t *ch
 }
 
 meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_node_t *node, uint16_t port, meshlink_channel_receive_cb_t cb, const void *data, size_t len, uint32_t flags) {
-       if(data || len) {
+       if(data && len) {
                abort();        // TODO: handle non-NULL data
        }
 
@@ -3183,6 +3183,11 @@ meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_n
        meshlink_channel_t *channel = xzalloc(sizeof(*channel));
        channel->node = n;
        channel->receive_cb = cb;
+
+       if(data && !len) {
+               channel->priv = (void *)data;
+       }
+
        channel->c = utcp_connect_ex(n->utcp, port, channel_recv, channel, flags);
 
        pthread_mutex_unlock(&mesh->mutex);

diff --git a/src/meshlink.h b/src/meshlink.h
index 11395f043a02d6acd2e95cc39cdce68831ca30be..e043d8d28f3a402dc52e7ed4f9ffc554a8ee1c60 100644 (file)
--- a/src/meshlink.h
+++ b/src/meshlink.h
@@ -1171,6 +1171,7 @@ extern void meshlink_set_channel_rcvbuf(struct meshlink_handle *mesh, struct mes
  *                      The pointer may be NULL, in which case incoming data is ignored.
  *  @param data         A pointer to a buffer containing data to already queue for sending, or NULL if there is no data to send.
  *                      After meshlink_send() returns, the application is free to overwrite or free this buffer.
+ *                      If len is 0, the data pointer is copied into the channel's priv member.
  *  @param len          The length of the data, or 0 if there is no data to send.
  *  @param flags        A bitwise-or'd combination of flags that set the semantics for this channel.
  *
@@ -1199,6 +1200,7 @@ extern struct meshlink_channel *meshlink_channel_open_ex(struct meshlink_handle
  *  @param data         A pointer to a buffer containing data to already queue for sending, or NULL if there is no data to send.
  *                      After meshlink_send() returns, the application is free to overwrite or free this buffer.
  *  @param len          The length of the data, or 0 if there is no data to send.
+ *                      If len is 0, the data pointer is copied into the channel's priv member.
  *
  *  @return             A handle for the channel, or NULL in case of an error.
  *                      The handle is valid until meshlink_channel_close() is called.