libvhost-user: Fix resource leak

Free the mmaped memory when we need to mmap new memory
space on vu_set_mem_table_exec() and vu_set_log_base_exec() to
avoid memory leak.

Also close the corresponding fd after mmap() on
vu_set_log_base_exec() to avoid fd leak.
Signed-off-by: NYongji Xie <xieyongji@baidu.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

contrib/libvhost-user/libvhost-user.c

@@ -407,6 +407,15 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
 {
     int i;
     VhostUserMemory *memory = &vmsg->payload.memory;
+
+    for (i = 0; i < dev->nregions; i++) {
+        VuDevRegion *r = &dev->regions[i];
+        void *m = (void *) (uintptr_t) r->mmap_addr;
+
+        if (m) {
+            munmap(m, r->size + r->mmap_offset);
+        }
+    }
     dev->nregions = memory->nregions;
 
     DPRINT("Nregions: %d\n", memory->nregions);
@@ -472,9 +481,14 @@ vu_set_log_base_exec(VuDev *dev, VhostUserMsg *vmsg)
 
     rc = mmap(0, log_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
               log_mmap_offset);
+    close(fd);
     if (rc == MAP_FAILED) {
         perror("log mmap error");
     }
+
+    if (dev->log_table) {
+        munmap(dev->log_table, dev->log_size);
+    }
     dev->log_table = rc;
     dev->log_size = log_mmap_size;