Re: [Qemu-devel] [PATCH v2 06/15] qga: Use return values instead of error_is_set(errp)

[Michael Roth]

Quoting Markus Armbruster (2014-04-28 15:27:45)
> Using error_is_set(errp) to check whether a function call failed is
> fragile: it breaks when errp is null.  ga_get_fd_handle() and
> guest_file_handle_add() don't return a useful value when they fail,
> but that's just stupid.  Fix that, and check them instead.  As far
> as I can tell, errp can't be null there, but this is more robust and
> more obviously correct.
> 
> Signed-off-by: Markus Armbruster <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>

Reviewed-by: Michael Roth <address@hidden>

> ---
>  qga/commands-posix.c | 6 +++---
>  qga/main.c           | 1 +
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index f6af7d1..6af974f 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -223,8 +223,8 @@ static int64_t guest_file_handle_add(FILE *fh, Error 
> **errp)
>      int64_t handle;
> 
>      handle = ga_get_fd_handle(ga_state, errp);
> -    if (error_is_set(errp)) {
> -        return 0;
> +    if (handle < 0) {
> +        return -1;
>      }
> 
>      gfh = g_malloc0(sizeof(GuestFileHandle));
> @@ -407,7 +407,7 @@ int64_t qmp_guest_file_open(const char *path, bool 
> has_mode, const char *mode,
>      }
> 
>      handle = guest_file_handle_add(fh, errp);
> -    if (error_is_set(errp)) {
> +    if (handle < 0) {
>          fclose(fh);
>          return -1;
>      }
> diff --git a/qga/main.c b/qga/main.c
> index d838c3e..eb792a3 100644
> --- a/qga/main.c
> +++ b/qga/main.c
> @@ -910,6 +910,7 @@ int64_t ga_get_fd_handle(GAState *s, Error **errp)
> 
>      if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
>          error_setg(errp, "failed to commit persistent state to disk");
> +        return -1;
>      }
> 
>      return handle;
> -- 
> 1.8.1.4