Diagnose empty commands in remctl_command

Return an error if an empty command is passed into remctl_command
rather than attempting to malloc zero bytes.

Change-Id: I92c52be3ae737cc906acc3385c2b4b9d6474f7a4
Reviewed-on: https://gerrit.stanford.edu/948
Reviewed-by: Russ Allbery <rra@stanford.edu>
Tested-by: Russ Allbery <rra@stanford.edu>

1 files changed, 4 insertions, 0 deletions

diff --git a/client/api.c b/client/api.c
index 27ae7b8..5eb2b78 100644
--- a/client/api.c
+++ b/client/api.c
@@ -503,6 +503,10 @@ remctl_command(struct remctl *r, const char **command)
 
     for (count = 0; command[count] != NULL; count++)
         ;
+    if (count == 0) {
+        internal_set_error(r, "cannot send empty command");
+        return 0;
+    }
     vector = malloc(sizeof(struct iovec) * count);
     if (vector == NULL) {
         internal_set_error(r, "cannot allocate memory: %s", strerror(errno));