From 3119b6aafde26342b3f4a64d3aa3fced107b95c0 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Jun 29 2016 23:16:41 +0000
Subject: __ntapi_tt_statfs: refactor, explicit string comparison.


---

diff --git a/src/fs/ntapi_tt_statfs.c b/src/fs/ntapi_tt_statfs.c
index df5a971..bc4fe51 100644
--- a/src/fs/ntapi_tt_statfs.c
+++ b/src/fs/ntapi_tt_statfs.c
@@ -23,7 +23,6 @@ int32_t __stdcall __ntapi_tt_statfs(
 	nt_oa			oa;
 	nt_iosb			iosb;
 	nt_unicode_string *	sdev;
-	uint32_t		hash;
 	wchar16_t *		wch;
 	wchar16_t *		wch_mark;
 	uint32_t		offset;
@@ -49,15 +48,15 @@ int32_t __stdcall __ntapi_tt_statfs(
 		oa.sec_qos = 0;
 
 		/* open file/folder */
-		status = __ntapi->zw_open_file(
-			&hfile,
-			NT_SEC_SYNCHRONIZE | NT_FILE_READ_ATTRIBUTES | NT_FILE_READ_ACCESS,
-			&oa,
-			&iosb,
-			NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
-			NT_FILE_SYNCHRONOUS_IO_ALERT);
-
-		if (status != NT_STATUS_SUCCESS)
+		if ((status = __ntapi->zw_open_file(
+				&hfile,
+				NT_SEC_SYNCHRONIZE
+					| NT_FILE_READ_ATTRIBUTES
+					| NT_FILE_READ_ACCESS,
+				&oa,
+				&iosb,
+				NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
+				NT_FILE_SYNCHRONOUS_IO_ALERT)))
 			return status;
 
 		statfs->flags_out = NT_STATFS_NEW_HANDLE;
@@ -67,19 +66,18 @@ int32_t __stdcall __ntapi_tt_statfs(
 	statfs->flags_in = flags;
 
 	/* maximum component length, file system type */
-	status = __ntapi->zw_query_volume_information_file(
-		hfile,
-		&iosb,
-		buffer,
-		buffer_size,
-		NT_FILE_FS_ATTRIBUTE_INFORMATION);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_volume_information_file(
+			hfile,
+			&iosb,
+			buffer,
+			buffer_size,
+			NT_FILE_FS_ATTRIBUTE_INFORMATION)))
 		return status;
 
 	fsai = (nt_fsai *)buffer;
-	statfs->f_type = 0;
+	statfs->f_type    = 0;
 	statfs->f_namelen = fsai->maximum_component_name_length;
+
 	statfs->nt_fstype_hash = __ntapi->tt_buffer_crc32(
 		0,
 		&fsai->file_system_name,
@@ -113,14 +111,12 @@ int32_t __stdcall __ntapi_tt_statfs(
 	statfs->f_ffree = (size_t)statfs->f_files >> 4 << 3;
 
 	/* file system size information */
-	status = __ntapi->zw_query_volume_information_file(
-		hfile,
-		&iosb,
-		buffer,
-		buffer_size,
-		NT_FILE_FS_FULL_SIZE_INFORMATION);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_volume_information_file(
+			hfile,
+			&iosb,
+			buffer,
+			buffer_size,
+			NT_FILE_FS_FULL_SIZE_INFORMATION)))
 		return status;
 
 	fsfsi = (nt_fsfsi *)buffer;
@@ -130,40 +126,43 @@ int32_t __stdcall __ntapi_tt_statfs(
 	statfs->f_bsize  = fsfsi->sectors_per_allocation_unit * fsfsi->bytes_per_sector;
 	statfs->f_frsize = fsfsi->bytes_per_sector;
 
-	/* TODO: consolidate with istat */
 	/* system-unique device name */
-	iosb.info = 0;
-	status = __ntapi->zw_query_object(
-		hfile,
-		NT_OBJECT_NAME_INFORMATION,
-		buffer,
-		buffer_size,
-		(uint32_t *)&iosb.info);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_object(
+			hfile,
+			NT_OBJECT_NAME_INFORMATION,
+			buffer,
+			buffer_size,
+			(uint32_t *)&iosb.info)))
 		return status;
 
 	sdev = (nt_unicode_string *)buffer;
+	wch  = sdev->buffer;
 
 	if (sdev->strlen < __DEVICE_PATH_PREFIX_LEN)
 		return NT_STATUS_INVALID_HANDLE;
 
-	hash = __ntapi->tt_buffer_crc32(
-		0,
-		sdev->buffer,
-		__DEVICE_PATH_PREFIX_LEN);
-
-	if (hash != __DEVICE_PATH_PREFIX_HASH)
+	if ((wch[0] != '\\')
+			|| (wch[1] != 'D')
+			|| (wch[2] != 'e')
+			|| (wch[3] != 'v')
+			|| (wch[4] != 'i')
+			|| (wch[5] != 'c')
+			|| (wch[6] != 'e')
+			|| (wch[7] != '\\'))
 		return NT_STATUS_INVALID_HANDLE;
 
-	wch_mark = sdev->buffer + __DEVICE_PATH_PREFIX_LEN/sizeof(wchar16_t);
-	wch = wch_mark;
-	while (*wch != '\\') wch++;
-	statfs->dev_name_strlen = (uint16_t)((wch - sdev->buffer) * sizeof(uint16_t));
+	wch_mark = &wch[8];
+	wch      = wch_mark;
+
+	while (*wch != '\\')
+		wch++;
+
+	statfs->dev_name_strlen    = (uint16_t)((wch - sdev->buffer) * sizeof(uint16_t));
 	statfs->record_name_strlen = sdev->strlen - statfs->dev_name_strlen;
 
 	statfs->dev_name_hash = __ntapi->tt_buffer_crc32(
-		hash,wch_mark,
+		__DEVICE_PATH_PREFIX_HASH,
+		wch_mark,
 		sizeof(wchar16_t) * (wch - wch_mark));
 
 	/* copy device name (optional, no failure) */
@@ -204,17 +203,15 @@ int32_t __stdcall __ntapi_tt_statfs(
 	*(--wch) = statfs->dev_name_strlen;
 	offset   = sizeof(nt_unicode_string) + statfs->dev_name_strlen;
 
-	status = __ntapi->tt_get_dos_drive_mount_points(
-		(void *)0,
-		(wchar16_t *)0,
-		(nt_mount_dev_name *)wch,
-		mnt_points_buffer,
-		buffer_size - offset);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->tt_get_dos_drive_mount_points(
+			(void *)0,
+			(wchar16_t *)0,
+			(nt_mount_dev_name *)wch,
+			mnt_points_buffer,
+			buffer_size - offset)))
 		return status;
 
-	offset = ((nt_mount_point_param *)mnt_points_buffer)->mount_points_offset;
+	offset     = ((nt_mount_point_param *)mnt_points_buffer)->mount_points_offset;
 	mnt_points = (nt_mount_points *)((uintptr_t)mnt_points_buffer + offset);
 
 	status = __ntapi->tt_dev_mount_points_to_statfs(