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

[Davidlohr Bueso <dave@gnu.org>]

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.

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