sd-rtnl: socket_read - use a read buffer

Rather than allocating/freeing memory for each message read, keep a global read buffer
in the rtnl object. Also, rather than using a fixed size, peek at the pending message
header to get the message size and reallocate as necessary.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libsystemd/sd-rtnl/sd-rtnl.c b/src/libsystemd/sd-rtnl/sd-rtnl.c
index 367f165a1c..e4d436bb17 100644
--- a/src/libsystemd/sd-rtnl/sd-rtnl.c
+++ b/src/libsystemd/sd-rtnl/sd-rtnl.c
@@ -54,6 +54,12 @@ static int sd_rtnl_new(sd_rtnl **ret) {
         if (!GREEDY_REALLOC(rtnl->wqueue, rtnl->wqueue_allocated, 1))
                 return -ENOMEM;
 
+        /* We guarantee that the read buffer has at least space for
+         * a message header */
+        if (!greedy_realloc((void**)&rtnl->rbuffer, &rtnl->rbuffer_allocated,
+                            sizeof(struct nlmsghdr), sizeof(uint8_t)))
+                return -ENOMEM;
+
         *ret = rtnl;
         rtnl = NULL;
 
@@ -133,6 +139,8 @@ sd_rtnl *sd_rtnl_unref(sd_rtnl *rtnl) {
                         sd_rtnl_message_unref(rtnl->wqueue[i]);
                 free(rtnl->wqueue);
 
+                free(rtnl->rbuffer);
+
                 hashmap_free_free(rtnl->reply_callbacks);
                 prioq_free(rtnl->reply_callbacks_prioq);