statfs.2

早期freebsd实现

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.\"	@(#)statfs.2	8.3 (Berkeley) 2/11/94
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.Dd February 11, 1994
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs
.Nd get file system statistics
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn statfs "const char *path" "struct statfs *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Sh DESCRIPTION
.Fn Statfs
returns information about a mounted file system.
.Fa Path
is the path name of any file within the mounted filesystem.
.Fa Buf
is a pointer to a
.Fn statfs
structure defined as follows:
.Bd -literal
typedef quad fsid_t;

#define MNAMELEN 90	/* length of buffer for returned name */

struct statfs {
short	f_type;		  /* type of filesystem (see below) */
short	f_flags;	  /* copy of mount flags */
long	f_bsize;	  /* fundamental file system block size */
long	f_iosize;	  /* optimal transfer block size */
long	f_blocks;	  /* total data blocks in file system */
long	f_bfree;	  /* free blocks in fs */
long	f_bavail;	  /* free blocks avail to non-superuser */
long	f_files;	  /* total file nodes in file system */
long	f_ffree;	  /* free file nodes in fs */
fsid_t	f_fsid;		  /* file system id */
long	f_spare[9];	  /* spare for later */
char	f_mntonname[MNAMELEN];	  /* mount point */
char	f_mntfromname[MNAMELEN];  /* mounted filesystem */
};
/*
* File system types.
*/
#define	MOUNT_UFS	1	/* Fast Filesystem */
#define	MOUNT_NFS	2	/* Sun-compatible Network Filesystem */
#define	MOUNT_MFS	3	/* Memory-based Filesystem */
#define	MOUNT_MSDOS	4	/* MS/DOS Filesystem */
#define	MOUNT_LFS	5	/* Log-based Filesystem */
#define	MOUNT_LOFS	6	/* Loopback Filesystem */
#define	MOUNT_FDESC	7	/* File Descriptor Filesystem */
#define	MOUNT_PORTAL	8	/* Portal Filesystem */
#define MOUNT_NULL	9	/* Minimal Filesystem Layer */
#define MOUNT_UMAP	10	/* Uid/Gid Remapping Filesystem */
#define MOUNT_KERNFS	11	/* Kernel Information Filesystem */
#define MOUNT_PROCFS	12	/* /proc Filesystem */
#define MOUNT_AFS	13	/* Andrew Filesystem */
#define MOUNT_CD9660	14	/* ISO9660 (aka CDROM) Filesystem */
#define MOUNT_UNION	15	/* Union (translucent) Filesystem */
.Ed
.Pp
Fields that are undefined for a particular file system are set to -1.
.Fn Fstatfs
returns the same information about an open file referenced by descriptor
.Fa fd .
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn Statfs
fails if one or more of the following are true:
.Bl -tag -width ENAMETOOLONGA
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa Path
is not a directory.
.It Bq Er EINVAL
.Fa path
contains a character with the high-order bit set.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds 255 characters,
or the length of
.Fa path
exceeds 1023 characters.
.It Bq Er ENOENT
The file referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
.Fa Buf
or
.Fa path
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Pp
.Fn Fstatfs
fails if one or more of the following are true:
.Bl -tag -width ENAMETOOLONGA
.It Bq Er EBADF
.Fa Fd
is not a valid open file descriptor.
.It Bq Er EFAULT
.Fa Buf
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Sh HISTORY
The
.Nm statfs
function first appeared in 4.4BSD.