libfdisk: check for collisions when create new label

We need to be sure that when create a new disklabel than the old label
will be removed.

Addresses: https://github.com/karelzak/util-linux/issues/410
Signed-off-by: Karel Zak <kzak@redhat.com>

4 files changed, 57 insertions, 50 deletions

diff --git a/libfdisk/src/context.c b/libfdisk/src/context.c
index 5b0fed928..77bc19c94 100644
--- a/libfdisk/src/context.c
+++ b/libfdisk/src/context.c
@@ -500,55 +500,6 @@ static void reset_context(struct fdisk_context *cxt)
 	fdisk_free_wipe_areas(cxt);
 }
 
-/*
- * This function prints a warning if the device is not wiped (e.g. wipefs(8).
- * Please don't call this function if there is already a PT.
- *
- * Returns: 0 if nothing found, < 0 on error, 1 if found a signature
- */
-static int check_collisions(struct fdisk_context *cxt)
-{
-#ifdef HAVE_LIBBLKID
-	int rc = 0;
-	blkid_probe pr;
-
-	assert(cxt);
-	assert(cxt->dev_fd >= 0);
-
-	DBG(CXT, ul_debugobj(cxt, "wipe check: initialize libblkid prober"));
-
-	pr = blkid_new_probe();
-	if (!pr)
-		return -ENOMEM;
-	rc = blkid_probe_set_device(pr, cxt->dev_fd, 0, 0);
-	if (rc)
-		return rc;
-
-	blkid_probe_enable_superblocks(pr, 1);
-	blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_TYPE);
-	blkid_probe_enable_partitions(pr, 1);
-
-	/* we care about the first found FS/raid, so don't call blkid_do_probe()
-	 * in loop or don't use blkid_do_fullprobe() ... */
-	rc = blkid_do_probe(pr);
-	if (rc == 0) {
-		const char *name = NULL;
-
-		if (blkid_probe_lookup_value(pr, "TYPE", &name, 0) == 0 ||
-		    blkid_probe_lookup_value(pr, "PTTYPE", &name, 0) == 0) {
-			cxt->collision = strdup(name);
-			if (!cxt->collision)
-				rc = -ENOMEM;
-		}
-	}
-
-	blkid_free_probe(pr);
-	return rc;
-#else
-	return 0;
-#endif
-}
-
 /**
  * fdisk_assign_device:
  * @cxt: context
@@ -621,7 +572,8 @@ int fdisk_assign_device(struct fdisk_context *cxt,
 
 	/* warn about obsolete stuff on the device if we aren't in
 	 * list-only mode and there is not PT yet */
-	if (!fdisk_is_listonly(cxt) && !fdisk_has_label(cxt) && check_collisions(cxt) < 0)
+	if (!fdisk_is_listonly(cxt) && !fdisk_has_label(cxt)
+	    && fdisk_check_collisions(cxt) < 0)
 		goto fail;
 
 	DBG(CXT, ul_debugobj(cxt, "initialized for %s [%s]",
diff --git a/libfdisk/src/fdiskP.h b/libfdisk/src/fdiskP.h
index 99d7fdc9c..ca20ffb8f 100644
--- a/libfdisk/src/fdiskP.h
+++ b/libfdisk/src/fdiskP.h
@@ -477,5 +477,6 @@ void fdisk_free_wipe_areas(struct fdisk_context *cxt);
 int fdisk_set_wipe_area(struct fdisk_context *cxt, uint64_t start, uint64_t size, int enable);
 int fdisk_do_wipe(struct fdisk_context *cxt);
 int fdisk_has_wipe_area(struct fdisk_context *cxt, uint64_t start, uint64_t size);
+int fdisk_check_collisions(struct fdisk_context *cxt);
 
 #endif /* _LIBFDISK_PRIVATE_H */
diff --git a/libfdisk/src/label.c b/libfdisk/src/label.c
index 52f9ec5ea..1319284b0 100644
--- a/libfdisk/src/label.c
+++ b/libfdisk/src/label.c
@@ -367,6 +367,10 @@ int fdisk_create_disklabel(struct fdisk_context *cxt, const char *name)
 	lb = fdisk_get_label(cxt, name);
 	if (!lb || lb->disabled)
 		return -EINVAL;
+
+	if (!haslabel || (lb && cxt->label != lb))
+		fdisk_check_collisions(cxt);
+
 	if (!lb->op->create)
 		return -ENOSYS;
 
diff --git a/libfdisk/src/wipe.c b/libfdisk/src/wipe.c
index e773f756d..c58015d0e 100644
--- a/libfdisk/src/wipe.c
+++ b/libfdisk/src/wipe.c
@@ -143,3 +143,53 @@ int fdisk_do_wipe(struct fdisk_context *cxt)
 #endif
 	return 0;
 }
+
+
+/*
+ * Please don't call this function if there is already a PT.
+ *
+ * Returns: 0 if nothing found, < 0 on error, 1 if found a signature
+ */
+int fdisk_check_collisions(struct fdisk_context *cxt)
+{
+#ifdef HAVE_LIBBLKID
+	int rc = 0;
+	blkid_probe pr;
+
+	assert(cxt);
+	assert(cxt->dev_fd >= 0);
+
+	DBG(CXT, ul_debugobj(cxt, "wipe check: initialize libblkid prober"));
+
+	pr = blkid_new_probe();
+	if (!pr)
+		return -ENOMEM;
+	rc = blkid_probe_set_device(pr, cxt->dev_fd, 0, 0);
+	if (rc)
+		return rc;
+
+	blkid_probe_enable_superblocks(pr, 1);
+	blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_TYPE);
+	blkid_probe_enable_partitions(pr, 1);
+
+	/* we care about the first found FS/raid, so don't call blkid_do_probe()
+	 * in loop or don't use blkid_do_fullprobe() ... */
+	rc = blkid_do_probe(pr);
+	if (rc == 0) {
+		const char *name = NULL;
+
+		if (blkid_probe_lookup_value(pr, "TYPE", &name, 0) == 0 ||
+		    blkid_probe_lookup_value(pr, "PTTYPE", &name, 0) == 0) {
+			cxt->collision = strdup(name);
+			if (!cxt->collision)
+				rc = -ENOMEM;
+		}
+	}
+
+	blkid_free_probe(pr);
+	return rc;
+#else
+	return 0;
+#endif
+}
+