Re: [PATCH 03/10] fdisk: API: add fdisk_label_change

[Petr Uzel <petr.uzel@suse.cz>]

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On Sun, Jul 22, 2012 at 07:05:04PM +0200, Davidlohr Bueso wrote:
> From: Davidlohr Bueso <dave@gnu.org>
> 
> A new fdisk_label_change() function is added for situations when the disk label is
> changed (ie: creating a new sun label). This function only updates the label pointer
> in the context to use the newly specified label type.

Why can't we just call __probe_labels() after creating new label, e.g.
in soon-to-be introduced fdisk_label_create()?

> 
> Signed-off-by: Davidlohr Bueso <dave@gnu.org>
> ---
>  fdisks/fdisk.h         |    2 ++
>  fdisks/fdiskdoslabel.c |    1 +
>  fdisks/fdisksgilabel.c |    2 ++
>  fdisks/fdisksunlabel.c |    1 +
>  fdisks/utils.c         |   37 +++++++++++++++++++++++++++++++++++++
>  5 files changed, 43 insertions(+), 0 deletions(-)
> 
> diff --git a/fdisks/fdisk.h b/fdisks/fdisk.h
> index d716824..d7e85f5 100644
> --- a/fdisks/fdisk.h
> +++ b/fdisks/fdisk.h
> @@ -104,6 +104,7 @@ enum fdisk_error {
>  	FDISK_ERROR_WRITE,
>  	FDISK_ERROR_IOCTL,
>  	FDISK_ERROR_PROBE,
> +	FDISK_ERROR_NOLABEL,
>  	FDISK_ERROR_UNKNOWN
>  };
>  
> @@ -164,6 +165,7 @@ extern void fdisk_mbr_zeroize(struct fdisk_context *cxt);
>  extern void fdisk_geom_set_cyls(struct fdisk_context *cxt);
>  extern const char *fdisk_error_name(enum fdisk_error errcode);
>  extern void fdisk_error_fatal(struct fdisk_context *cxt, enum fdisk_error errcode);
> +extern int fdisk_label_change(struct fdisk_context *cxt, const char *name);
>  
>  /* prototypes for fdisk.c */
>  extern char *disk_device, *line_ptr;
> diff --git a/fdisks/fdiskdoslabel.c b/fdisks/fdiskdoslabel.c
> index 535afdc..9b9b23a 100644
> --- a/fdisks/fdiskdoslabel.c
> +++ b/fdisks/fdiskdoslabel.c
> @@ -230,6 +230,7 @@ void create_doslabel(struct fdisk_context *cxt)
>  
>  	dos_init(cxt);
>  	fdisk_mbr_zeroize(cxt);
> +	fdisk_label_change(cxt, "dos");
>  	set_all_unchanged();
>  	set_changed(0);
>  
> diff --git a/fdisks/fdisksgilabel.c b/fdisks/fdisksgilabel.c
> index e38d98f..6001038 100644
> --- a/fdisks/fdisksgilabel.c
> +++ b/fdisks/fdisksgilabel.c
> @@ -780,6 +780,8 @@ create_sgilabel(struct fdisk_context *cxt)
>  		}
>  
>  	fdisk_mbr_zeroize(cxt);
> +	fdisk_label_change(cxt, "sgi");
> +
>  	sgilabel->magic = SSWAP32(SGI_LABEL_MAGIC);
>  	sgilabel->boot_part = SSWAP16(0);
>  	sgilabel->swap_part = SSWAP16(1);
> diff --git a/fdisks/fdisksunlabel.c b/fdisks/fdisksunlabel.c
> index 4123806..b63335c 100644
> --- a/fdisks/fdisksunlabel.c
> +++ b/fdisks/fdisksunlabel.c
> @@ -161,6 +161,7 @@ void create_sunlabel(struct fdisk_context *cxt)
>  
>  	init();
>  	fdisk_mbr_zeroize(cxt);
> +	fdisk_label_change(cxt, "sun");
>  
>  	sunlabel->magic = SSWAP16(SUN_LABEL_MAGIC);
>  	sunlabel->sanity = SSWAP32(SUN_LABEL_SANE);
> diff --git a/fdisks/utils.c b/fdisks/utils.c
> index cf9484c..48dedfb 100644
> --- a/fdisks/utils.c
> +++ b/fdisks/utils.c
> @@ -44,6 +44,43 @@ static const struct fdisk_label *labels[] =
>  	&mac_label,
>  };
>  
> +/**
> + * fdisk_label_change:
> + * @cxt: fdisk context
> + * @name: new label name
> + *
> + * Updates the disk label type to the one specified by @name.
> + *
> + * Returns 0 on success, otherwise, a corresponding error.
> + */
> +int fdisk_label_change(struct fdisk_context *cxt, const char *name)
> +{
> +	int i;
> +
> +	if (!cxt || !cxt->label || !name)
> +		return FDISK_ERROR_UNKNOWN;
> +
> +	/* not really changing the label */
> +	if (!strncmp(name, cxt->label->name, strlen(name)))
> +		goto done;
> +
> +	for (i = 0; i < ARRAY_SIZE(labels); i++) {
> +		if (strncmp(name, labels[i]->name, strlen(name)))
> +			continue;
> +	
> +		/* found the new label */
> +		memset(cxt->label, 0, sizeof(struct fdisk_label));
> +		memcpy(cxt->label, labels[i], sizeof(struct fdisk_label));
> +		DBG(LABEL, dbgprint("changing to a %s label\n", labels[i]->name));
> +		goto done;
> +	}
> +
> +	/* couldn't find the requested label type */
> +	return FDISK_ERROR_NOLABEL;
> +done:
> +	return 0;
> +}
> +
>  static int __probe_labels(struct fdisk_context *cxt)
>  {
>  	int i, rc = 0;
> -- 
> 1.7.4.1
> 
> 
> 
> 
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Petr

-- 
Petr Uzel
IRC: ptr_uzl @ freenode

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