include/uapi/linux/msdos_fs.h

Source file repositories/reference/linux-study-clean/include/uapi/linux/msdos_fs.h

File Facts

System
Linux kernel
Corpus path
include/uapi/linux/msdos_fs.h
Extension
.h
Size
6746 bytes
Lines
198
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct __fat_dirent {
	long		d_ino;
	__kernel_off_t	d_off;
	unsigned short	d_reclen;
	char		d_name[256]; /* We must not include limits.h! */
};

/*
 * ioctl commands
 */
#define VFAT_IOCTL_READDIR_BOTH		_IOR('r', 1, struct __fat_dirent[2])
#define VFAT_IOCTL_READDIR_SHORT	_IOR('r', 2, struct __fat_dirent[2])
/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
#define FAT_IOCTL_GET_ATTRIBUTES	_IOR('r', 0x10, __u32)
#define FAT_IOCTL_SET_ATTRIBUTES	_IOW('r', 0x11, __u32)
/*Android kernel has used 0x12, so we use 0x13*/
#define FAT_IOCTL_GET_VOLUME_ID		_IOR('r', 0x13, __u32)

struct fat_boot_sector {
	__u8	ignored[3];	/* Boot strap short or near jump */
	__u8	system_id[8];	/* Name - can be used to special case
				   partition manager volumes */
	__u8	sector_size[2];	/* bytes per logical sector */
	__u8	sec_per_clus;	/* sectors/cluster */
	__le16	reserved;	/* reserved sectors */
	__u8	fats;		/* number of FATs */
	__u8	dir_entries[2];	/* root directory entries */
	__u8	sectors[2];	/* number of sectors */
	__u8	media;		/* media code */
	__le16	fat_length;	/* sectors/FAT */
	__le16	secs_track;	/* sectors per track */
	__le16	heads;		/* number of heads */
	__le32	hidden;		/* hidden sectors (unused) */
	__le32	total_sect;	/* number of sectors (if sectors == 0) */

	union {
		struct {
			/*  Extended BPB Fields for FAT16 */
			__u8	drive_number;	/* Physical drive number */
			__u8	state;		/* undocumented, but used
						   for mount state. */
			__u8	signature;  /* extended boot signature */
			__u8	vol_id[4];	/* volume ID */
			__u8	vol_label[MSDOS_NAME];	/* volume label */
			__u8	fs_type[8];		/* file system type */
			/* other fields are not added here */
		} fat16;

		struct {
			/* only used by FAT32 */
			__le32	length;		/* sectors/FAT */
			__le16	flags;		/* bit 8: fat mirroring,
						   low 4: active fat */
			__u8	version[2];	/* major, minor filesystem
						   version */
			__le32	root_cluster;	/* first cluster in
						   root directory */
			__le16	info_sector;	/* filesystem info sector */
			__le16	backup_boot;	/* backup boot sector */
			__le16	reserved2[6];	/* Unused */
			/* Extended BPB Fields for FAT32 */
			__u8	drive_number;   /* Physical drive number */
			__u8    state;       	/* undocumented, but used
						   for mount state. */
			__u8	signature;  /* extended boot signature */
			__u8	vol_id[4];	/* volume ID */
			__u8	vol_label[MSDOS_NAME];	/* volume label */
			__u8	fs_type[8];		/* file system type */
			/* other fields are not added here */
		} fat32;
	};
};

struct fat_boot_fsinfo {
	__le32   signature1;	/* 0x41615252L */
	__le32   reserved1[120];	/* Nothing as far as I can tell */
	__le32   signature2;	/* 0x61417272L */
	__le32   free_clusters;	/* Free cluster count.  -1 if unknown */
	__le32   next_cluster;	/* Most recently allocated cluster */
	__le32   reserved2[4];
};

struct msdos_dir_entry {
	__u8	name[MSDOS_NAME];/* name and extension */
	__u8	attr;		/* attribute bits */
	__u8    lcase;		/* Case for base and extension */
	__u8	ctime_cs;	/* Creation time, centiseconds (0-199) */
	__le16	ctime;		/* Creation time */
	__le16	cdate;		/* Creation date */
	__le16	adate;		/* Last access date */

Annotation

Implementation Notes