Re: [PATCH 1/4] migration: Prevent memleak by ...params_test_apply

[Eric Blake <eblake@redhat.com>]

On 6/30/20 3:45 AM, Max Reitz wrote:
> The created structure is not really a proper QAPI object, so we cannot
> and will not free its members.  Strings therein should therefore not be
> duplicated, or we will leak them.

This seems fragile to me; having to code QAPI usage differently 
depending on whether the containing struct was malloc'd or not (and 
therefore whether someone will call qapi_free_MigrateSetParameters or 
not) looks awkward to maintain.  We have 
visit_type_MigrateSetParameters_members, could that be used as a cleaner 
way to free all members of the struct without freeing the struct itself? 
  Should the QAPI generator start generating qapi_free_FOO_members to 
make such cleanup easier?

> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   migration/migration.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 481a590f72..47c7da4e55 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1336,12 +1336,12 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
>   
>       if (params->has_tls_creds) {
>           assert(params->tls_creds->type == QTYPE_QSTRING);
> -        dest->tls_creds = g_strdup(params->tls_creds->u.s);
> +        dest->tls_creds = params->tls_creds->u.s;
>       }
>   
>       if (params->has_tls_hostname) {
>           assert(params->tls_hostname->type == QTYPE_QSTRING);
> -        dest->tls_hostname = g_strdup(params->tls_hostname->u.s);
> +        dest->tls_hostname = params->tls_hostname->u.s;
>       }
>   
>       if (params->has_max_bandwidth) {
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org