Re: [Xen-devel] [PATCH] libxl: fix mutex initialization

[Christoph Egger <Christoph.Egger@xxxxxxx>]

On 01/13/12 14:12, Roger Pau Monne wrote:
> # HG changeset patch
> # User Roger Pau Monne<roger.pau@xxxxxxxxxxxxx>
> # Date 1326460029 -3600
> # Node ID bb6b01995d64f7c2887b7174536861b83ef04364
> # Parent  117ad4634ba11c10e45f3d86e6baff35d7d2691c
> libxl: fix mutex initialization
>
> The macro PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP is not defined on
> NetBSD, so define mutex attributes manually.
>
> Signed-off-by: Roger Pau Monne<roger.pau@xxxxxxxxxxxxx>
Acked-by: Christoph Egger <Christoph.Egger@xxxxxxx>

> diff -r 117ad4634ba1 -r bb6b01995d64 tools/libxl/libxl.c
> --- a/tools/libxl/libxl.c       Fri Jan 13 13:55:01 2012 +0100
> +++ b/tools/libxl/libxl.c       Fri Jan 13 14:07:09 2012 +0100
> @@ -41,7 +41,6 @@ int libxl_ctx_alloc(libxl_ctx **pctx, in
>   {
>       libxl_ctx *ctx;
>       struct stat stat_buf;
> -    const pthread_mutex_t mutex_value = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
>
>       if (version != LIBXL_VERSION)
>           return ERROR_VERSION;
> @@ -55,10 +54,10 @@ int libxl_ctx_alloc(libxl_ctx **pctx, in
>       memset(ctx, 0, sizeof(libxl_ctx));
>       ctx->lg = lg;
>
> -    /* This somewhat convoluted approach is needed because
> -     * PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP is defined to be valid
> -     * only as an initialiser, not as an expression. */
> -    memcpy(&ctx->lock,&mutex_value, sizeof(ctx->lock));
> +    if (libxl__init_recursive_mutex(ctx,&ctx->lock)<  0) {
> +        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Failed to initialize mutex");
> +        return ERROR_FAIL;
> +    }
>
>       if ( stat(XENSTORE_PID_FILE,&stat_buf) != 0 ) {
>           LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "Is xenstore daemon 
> running?\n"
> diff -r 117ad4634ba1 -r bb6b01995d64 tools/libxl/libxl_internal.c
> --- a/tools/libxl/libxl_internal.c      Fri Jan 13 13:55:01 2012 +0100
> +++ b/tools/libxl/libxl_internal.c      Fri Jan 13 14:07:09 2012 +0100
> @@ -304,6 +304,28 @@ _hidden int libxl__compare_macs(libxl_ma
>       return 0;
>   }
>
> +_hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t *lock)
> +{
> +    pthread_mutexattr_t attr;
> +
> +    if (pthread_mutexattr_init(&attr) != 0) {
> +        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
> +                         "Failed to init mutex attributes\n");
> +        return ERROR_FAIL;
> +    }
> +    if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) != 0) {
> +        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
> +                         "Failed to set mutex attributes\n");
> +        return ERROR_FAIL;
> +    }
> +    if (pthread_mutex_init(lock,&attr) != 0) {
> +        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
> +                         "Failed to init mutex\n");
> +        return ERROR_FAIL;
> +    }
> +    return 0;
> +}
> +
>   libxl_device_model_version libxl__device_model_version_running(libxl__gc *gc,
>                                                                  uint32_t domid)
>   {
> diff -r 117ad4634ba1 -r bb6b01995d64 tools/libxl/libxl_internal.h
> --- a/tools/libxl/libxl_internal.h      Fri Jan 13 13:55:01 2012 +0100
> +++ b/tools/libxl/libxl_internal.h      Fri Jan 13 14:07:09 2012 +0100
> @@ -606,6 +606,8 @@ _hidden int libxl__e820_alloc(libxl__gc
>   _hidden int libxl__parse_mac(const char *s, libxl_mac mac);
>   /* compare mac address @a and @b. 0 if the same, -ve if a<b and +ve if a>b */
>   _hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b);
> +/* init a recursive mutex */
> +_hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t *lock);
>
>   #define STRINGIFY(x) #x
>   #define TOSTRING(x) STRINGIFY(x)
>
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

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