libfdisk: extend API to provide label specific geometry ranges

Now fdisk provides DOS specific geometry ranges in expert menu.

Addresses: https://github.com/karelzak/util-linux/issues/556
Signed-off-by: Karel Zak <kzak@redhat.com>

7 files changed, 138 insertions, 11 deletions

diff --git a/disk-utils/fdisk-menu.c b/disk-utils/fdisk-menu.c
index 8220d6586..b8a2e6003 100644
--- a/disk-utils/fdisk-menu.c
+++ b/disk-utils/fdisk-menu.c
@@ -151,7 +151,7 @@ static const struct menu menu_geo = {
 	.callback = geo_menu_cb,
 	.exclude = FDISK_DISKLABEL_GPT | FDISK_DISKLABEL_BSD,
 	.entries = {
-		MENU_XSEP(N_("Geometry")),
+		MENU_XSEP(N_("Geometry (for the current label)")),
 		MENU_XENT('c', N_("change number of cylinders")),
 		MENU_XENT('h', N_("change number of heads")),
 		MENU_XENT('s', N_("change number of sectors/track")),
@@ -1004,32 +1004,50 @@ static int bsd_menu_cb(struct fdisk_context **cxt0,
 	return rc;
 }
 
-/* C/H/S commands */
+/* C/H/S commands
+ *
+ * The geometry setting from this dialog is not persistent and maybe reseted by
+ * fdisk_reset_device_properties() (for example when you create a new disk
+ * label). Note that on command line specified -C/-H/-S setting is persistent
+ * as it's based on fdisk_save_user_geometry().
+ */
 static int geo_menu_cb(struct fdisk_context **cxt0,
 		       const struct menu *menu __attribute__((__unused__)),
 		       const struct menu_entry *ent)
 {
 	struct fdisk_context *cxt = *cxt0;
+	struct fdisk_label *lb = fdisk_get_label(cxt, NULL);
 	int rc = -EINVAL;
 	uintmax_t c = 0, h = 0, s = 0;
+	fdisk_sector_t mi, ma;
 
 	DBG(MENU, ul_debug("enter GEO menu"));
 
 	assert(cxt);
 	assert(ent);
 
+	/* default */
+	if (!lb)
+		lb = fdisk_get_label(cxt, "dos");
+
 	switch (ent->key) {
 	case 'c':
-		rc =  fdisk_ask_number(cxt, 1, fdisk_get_geom_cylinders(cxt),
-				1048576, _("Number of cylinders"), &c);
+		fdisk_label_get_geomrange_cylinders(lb, &mi, &ma);
+		rc =  fdisk_ask_number(cxt, mi, fdisk_get_geom_cylinders(cxt),
+				ma, _("Number of cylinders"), &c);
 		break;
 	case 'h':
-		rc =  fdisk_ask_number(cxt, 1, fdisk_get_geom_heads(cxt),
-				256, _("Number of heads"), &h);
+	{
+		unsigned int i, a;
+		fdisk_label_get_geomrange_heads(lb, &i, &a);
+		rc =  fdisk_ask_number(cxt, i, fdisk_get_geom_heads(cxt),
+				a, _("Number of heads"), &h);
 		break;
+	}
 	case 's':
-		rc =  fdisk_ask_number(cxt, 1, fdisk_get_geom_sectors(cxt),
-				63, _("Number of sectors"), &s);
+		fdisk_label_get_geomrange_sectors(lb, &mi, &ma);
+		rc =  fdisk_ask_number(cxt, mi, fdisk_get_geom_sectors(cxt),
+				ma, _("Number of sectors"), &s);
 		break;
 	}
 
diff --git a/libfdisk/src/dos.c b/libfdisk/src/dos.c
index 9759ce2e0..fd6e2cbb5 100644
--- a/libfdisk/src/dos.c
+++ b/libfdisk/src/dos.c
@@ -2485,6 +2485,14 @@ struct fdisk_label *fdisk_new_dos_label(struct fdisk_context *cxt)
 	lb->fields = dos_fields;
 	lb->nfields = ARRAY_SIZE(dos_fields);
 
+	lb->geom_min.sectors = 1;
+	lb->geom_min.heads = 1;
+	lb->geom_min.cylinders = 1;
+
+	lb->geom_max.sectors = 63;
+	lb->geom_max.heads = 256;
+	lb->geom_max.cylinders = 1048576;
+
 	return lb;
 }
 
diff --git a/libfdisk/src/fdiskP.h b/libfdisk/src/fdiskP.h
index b81d6fc7a..0b9d43413 100644
--- a/libfdisk/src/fdiskP.h
+++ b/libfdisk/src/fdiskP.h
@@ -279,6 +279,9 @@ struct fdisk_label {
 
 	int			flags;		/* FDISK_LABEL_FL_* flags */
 
+	struct fdisk_geometry	geom_min;	/* minimal geometry */
+	struct fdisk_geometry	geom_max;	/* maximal geometry */
+
 	unsigned int		changed:1,	/* label has been modified */
 				disabled:1;	/* this driver is disabled at all */
 
diff --git a/libfdisk/src/label.c b/libfdisk/src/label.c
index c1afdf1b9..304ea34e4 100644
--- a/libfdisk/src/label.c
+++ b/libfdisk/src/label.c
@@ -628,3 +628,73 @@ int fdisk_label_is_disabled(const struct fdisk_label *lb)
 	assert(lb);
 	return lb ? lb->disabled : 0;
 }
+
+/**
+ * fdisk_label_get_geomrange_sectors:
+ * @lb: label
+ * @mi: minimal number
+ * @ma: maximal number
+ *
+ * The function provides minimal and maximal geometry supported for the label,
+ * if no range defined by library than returns -ENOSYS.
+ *
+ * Returns: 0 on success, otherwise, a corresponding error.
+ */
+int fdisk_label_get_geomrange_sectors(const struct fdisk_label *lb,
+					fdisk_sector_t *mi, fdisk_sector_t *ma)
+{
+	if (!lb || lb->geom_min.sectors == 0)
+		return -ENOSYS;
+	if (mi)
+		*mi = lb->geom_min.sectors;
+	if (ma)
+		*ma = lb->geom_max.sectors;
+	return 0;
+}
+
+/**
+ * fdisk_label_get_geomrange_heads:
+ * @lb: label
+ * @mi: minimal number
+ * @ma: maximal number
+ *
+ * The function provides minimal and maximal geometry supported for the label,
+ * if no range defined by library than returns -ENOSYS.
+ *
+ * Returns: 0 on success, otherwise, a corresponding error.
+ */
+int fdisk_label_get_geomrange_heads(const struct fdisk_label *lb,
+					unsigned int *mi, unsigned int *ma)
+{
+	if (!lb || lb->geom_min.heads == 0)
+		return -ENOSYS;
+	if (mi)
+		*mi = lb->geom_min.heads;
+	if (ma)
+		*ma = lb->geom_max.heads;
+	return 0;
+}
+
+/**
+ * fdisk_label_get_geomrange_cylinders:
+ * @lb: label
+ * @mi: minimal number
+ * @ma: maximal number
+ *
+ * The function provides minimal and maximal geometry supported for the label,
+ * if no range defined by library than returns -ENOSYS.
+ *
+ * Returns: 0 on success, otherwise, a corresponding error.
+ */
+int fdisk_label_get_geomrange_cylinders(const struct fdisk_label *lb,
+					fdisk_sector_t *mi, fdisk_sector_t *ma)
+{
+	if (!lb || lb->geom_min.cylinders == 0)
+		return -ENOSYS;
+	if (mi)
+		*mi = lb->geom_min.cylinders;
+	if (ma)
+		*ma = lb->geom_max.cylinders;
+	return 0;
+}
+
diff --git a/libfdisk/src/libfdisk.h.in b/libfdisk/src/libfdisk.h.in
index 3586d6626..ddf4a91e6 100644
--- a/libfdisk/src/libfdisk.h.in
+++ b/libfdisk/src/libfdisk.h.in
@@ -321,6 +321,13 @@ extern int fdisk_locate_disklabel(struct fdisk_context *cxt, int n,
 				  uint64_t *offset,
 				  size_t *size);
 
+extern int fdisk_label_get_geomrange_cylinders(const struct fdisk_label *lb,
+			fdisk_sector_t *mi, fdisk_sector_t *ma);
+extern int fdisk_label_get_geomrange_heads(const struct fdisk_label *lb,
+                        unsigned int *mi, unsigned int *ma);
+extern int fdisk_label_get_geomrange_sectors(const struct fdisk_label *lb,
+                        fdisk_sector_t *mi, fdisk_sector_t *ma);
+
 /**
  * fdisk_labelitem_gen:
  *
diff --git a/libfdisk/src/libfdisk.sym b/libfdisk/src/libfdisk.sym
index 2c892a0c3..8d38332b9 100644
--- a/libfdisk/src/libfdisk.sym
+++ b/libfdisk/src/libfdisk.sym
@@ -291,3 +291,9 @@ FDISK_2.31 {
 	fdisk_has_dialogs;
 	fdisk_save_user_grain;
 } FDISK_2.30;
+
+FDISK_2.32 {
+	fdisk_label_get_geomrange_sectors;
+	fdisk_label_get_geomrange_heads;
+	fdisk_label_get_geomrange_cylinders;
+} FDISK_2.31;
diff --git a/libfdisk/src/sun.c b/libfdisk/src/sun.c
index 923b73e32..0be4d8df6 100644
--- a/libfdisk/src/sun.c
+++ b/libfdisk/src/sun.c
@@ -182,11 +182,19 @@ static void ask_geom(struct fdisk_context *cxt)
 
 	assert(cxt);
 
-	if (fdisk_ask_number(cxt, 1, 1, 1024, _("Heads"), &res) == 0)
+	if (fdisk_ask_number(cxt, cxt->label->geom_min.heads, 1,
+				  cxt->label->geom_max.heads,
+				  _("Heads"), &res) == 0)
 		cxt->geom.heads = res;
-	if (fdisk_ask_number(cxt, 1, 1, 1024, _("Sectors/track"), &res) == 0)
+
+	if (fdisk_ask_number(cxt, cxt->label->geom_min.sectors, 1,
+				  cxt->label->geom_max.sectors,
+				  _("Sectors/track"), &res) == 0)
 		cxt->geom.sectors = res;
-	if (fdisk_ask_number(cxt, 1, 1, USHRT_MAX, _("Cylinders"), &res) == 0)
+
+	if (fdisk_ask_number(cxt, cxt->label->geom_min.cylinders, 1,
+				  cxt->label->geom_max.cylinders,
+				  _("Cylinders"), &res) == 0)
 		cxt->geom.cylinders = res;
 }
 
@@ -1154,5 +1162,12 @@ struct fdisk_label *fdisk_new_sun_label(struct fdisk_context *cxt)
 	lb->nfields = ARRAY_SIZE(sun_fields);
 	lb->flags |= FDISK_LABEL_FL_REQUIRE_GEOMETRY;
 
+	lb->geom_min.sectors = 1;
+	lb->geom_min.heads = 1;
+	lb->geom_min.cylinders = 1;
+
+	lb->geom_max.sectors = 1024;
+	lb->geom_max.heads = 1024;
+	lb->geom_max.cylinders = USHRT_MAX;
 	return lb;
 }