Re: [Xen-devel] [PATCH 15/15] libxl: New event generation API

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2011-12-12 at 19:24 +0000, Stefano Stabellini wrote:
> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> index cd613f7..94bdbba 100644
> --- a/tools/libxl/libxl.c
> +++ b/tools/libxl/libxl.c
> @@ -63,6 +63,12 @@ int libxl_ctx_alloc(libxl_ctx **pctx, int version,
>       * only as an initialiser, not as an expression. */
>      memcpy(&ctx->lock, &mutex_value, sizeof(ctx->lock));
>  
> +    if(pthread_key_create(&ctx->tls_key, NULL) < 0) {
> +        LIBXL__LOG_ERRNOVAL(ctx, LIBXL__LOG_ERROR, errno,
> +            "cannot create tls key");
> +        return ERROR_FAIL;

You need a corresponding pthread_key_delete in the free function.

> [...]

> @@ -65,17 +66,41 @@ int libxl__ptr_add(libxl__gc *gc, void *ptr)
>      return 0;
>  }
>  
> +libxl__gc *libxl__init_gc(libxl_ctx *ctx)
> +{
> +    libxl__gc *gc = (libxl__gc *) pthread_getspecific(ctx->tls_key);
> +    if (gc == NULL) {
> +        gc = (libxl__gc *) malloc(sizeof(libxl__gc));
> +        if (gc == NULL)
> +            return NULL;
> +        gc->alloc_maxsize = 0;
> +        gc->alloc_ptrs = 0;
> +        gc->owner = ctx;
> +        gc->nested = 1;
> +        pthread_setspecific(ctx->tls_key, gc);

pthread_setspecific can fail. 

> [...]

>  void libxl__free_all(libxl__gc *gc)
>  {
>      void *ptr;
>      int i;
>  
> +    gc->nested--;
> +    if (gc->nested > 0)
> +        return;
> +
>      for (i = 0; i < gc->alloc_maxsize; i++) {
>          ptr = gc->alloc_ptrs[i];
>          gc->alloc_ptrs[i] = NULL;
>          free(ptr);
>      }
>      free(gc->alloc_ptrs);
> +    pthread_setspecific(CTX->tls_key, NULL);

As above this can also fail. I think this one might be a bit harder to
deal with in general.

> +    free(gc);
>  }
>  

Ian.



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