super partition: mount super partitions using fs_mgr

We are now requiring fstab v2 for android-10+ trees. You can
specify twrp flags using /etc/twrp.flags to label and
annotate partitions.

This patchset uses fs_mgr to load the super partition and build
device mapper blocks off vendor and system depending on the slot
in use. These are mapped to partitions in TWRP and allowed to
be mounted read-only. The super partition is also mapped into a
TWRP partition in order to backup the entire partition. You cannot
backup individual device mapper blocks due to the device can only
be read-only. Therefore you cannot write back to the device mapper.

Change-Id: Icc1d895dcf96ad5ba03989c9bf759419d83673a3

partition.cpp

@@ -268,6 +268,7 @@ TWPartition::TWPartition() {
 	Adopted_GUID = "";
 	SlotSelect = false;
 	Key_Directory = "";
+	Is_Super = false;
 }
 
 TWPartition::~TWPartition(void) {
@@ -285,6 +286,7 @@ bool TWPartition::Process_Fstab_Line(const char *fstab_line, bool Display_Error,
 	std::map<string, Flags_Map>::iterator it;
 
 	strlcpy(full_line, fstab_line, sizeof(full_line));
+
 	for (index = 0; index < line_len; index++) {
 		if (full_line[index] == 34)
 			skip = !skip;
@@ -300,6 +302,14 @@ bool TWPartition::Process_Fstab_Line(const char *fstab_line, bool Display_Error,
 		fs_index = 2;
 	}
 
+	Is_Super = PartitionManager.Is_Super_Partition(fstab_line);
+	if (Is_Super) {
+		block_device_index = 0;
+		fstab_version = 2;
+		mount_point_index = 1;
+		fs_index = 2;
+	}
+
 	index = 0;
 	while (index < line_len) {
 		while (index < line_len && full_line[index] == '\0')
@@ -309,7 +319,7 @@ bool TWPartition::Process_Fstab_Line(const char *fstab_line, bool Display_Error,
 		ptr = full_line + index;
 		if (item_index == mount_point_index) {
 			Mount_Point = ptr;
-			if (fstab_version == 2) {
+			if (fstab_version == 2 && Is_Super == false) {
 				additional_entry = PartitionManager.Find_Partition_By_Path(Mount_Point);
 				if (!Sar_Detect && additional_entry) {
 					LOGINFO("Found an additional entry for '%s'\n", Mount_Point.c_str());
@@ -342,11 +352,13 @@ bool TWPartition::Process_Fstab_Line(const char *fstab_line, bool Display_Error,
 				if (*ptr != '/')
 					LOGERR("Until we get better BML support, you will have to find and provide the full block device path to the BML devices e.g. /dev/block/bml9 instead of the partition name\n");
 			} else if (*ptr != '/') {
-				if (Display_Error)
-					LOGERR("Invalid block device '%s' in fstab line '%s'", ptr, fstab_line);
-				else
-					LOGINFO("Invalid block device '%s' in fstab line '%s'", ptr, fstab_line);
-				return false;
+				if (!Is_Super) {
+					if (Display_Error)
+						LOGERR("Invalid block device '%s' in fstab line '%s'", ptr, fstab_line);
+					else
+						LOGINFO("Invalid block device '%s' in fstab line '%s'", ptr, fstab_line);
+					return false;
+				}
 			} else {
 				Primary_Block_Device = ptr;
 				Find_Real_Block_Device(Primary_Block_Device, Display_Error);
@@ -617,6 +629,11 @@ bool TWPartition::Process_Fstab_Line(const char *fstab_line, bool Display_Error,
 			Storage_Path = Mount_Point;
 			Make_Dir(Mount_Point, Display_Error);
 		}
+		if (Is_Super) {
+			Can_Be_Backed_Up = false;
+			Can_Be_Wiped = false;
+			Wipe_Available_in_GUI = false;
+		}
 	}
 
 	return true;
@@ -1410,7 +1427,6 @@ bool TWPartition::Is_Mounted(void) {
 
 	// Compare the device IDs -- if they match then we're (probably) using tmpfs instead of an actual device
 	int ret = (st1.st_dev != st2.st_dev) ? true : false;
-
 	return ret;
 }
 
@@ -2865,6 +2881,9 @@ bool TWPartition::Update_Size(bool Display_Error) {
 
 	Find_Actual_Block_Device();
 
+	if (Actual_Block_Device.empty())
+		return false;
+
 	if (!Can_Be_Mounted && !Is_Encrypted) {
 		if (TWFunc::Path_Exists(Actual_Block_Device) && Find_Partition_Size()) {
 			Used = Size;
@@ -2875,6 +2894,7 @@ bool TWPartition::Update_Size(bool Display_Error) {
 	}
 
 	Was_Already_Mounted = Is_Mounted();
+
 	if (Removable || Is_Encrypted) {
 		if (!Mount(false))
 			return true;
@@ -3374,3 +3394,24 @@ void TWPartition::Set_Backup_FileName(string fname) {
 string TWPartition::Get_Backup_Name() {
 	return Backup_Name;
 }
+
+string TWPartition::Get_Mount_Point() {
+	return Mount_Point;
+}
+
+void TWPartition::Set_Block_Device(std::string block_device) {
+	Primary_Block_Device = Actual_Block_Device = block_device;
+}
+
+bool TWPartition::Get_Super_Status() {
+	return Is_Super;
+}
+
+void TWPartition::Set_Can_Be_Backed_Up(bool val) {
+	Can_Be_Backed_Up = val;
+}
+
+void TWPartition::Set_Can_Be_Wiped(bool val) {
+	Can_Be_Wiped = val;
+	Wipe_Available_in_GUI = val;
+}