freebsd-nq/lib/libc/sys/getfsstat.2

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.\"	@(#)getfsstat.2	8.3 (Berkeley) 5/25/95
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.Dd May 25, 1995
.Dt GETFSSTAT 2
.Os
.Sh NAME
.Nm getfsstat
.Nd get list of all mounted filesystems
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/ucred.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn getfsstat "struct statfs *buf" "long bufsize" "int flags"
.Sh DESCRIPTION
.Fn Getfsstat
returns information about all mounted filesystems.
.Fa Buf
is a pointer to
.Xr statfs
structures defined as follows:
.Bd -literal
typedef struct fsid { int32_t val[2]; } fsid_t;	/* file system id type */

/*
 * file system statistics
 */

#define MFSNAMELEN 16	/* length of fs type name, including null */
#define MNAMELEN   90	/* length of buffer for returned name */

struct statfs {
    long    f_spare2;		/* placeholder */
    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 */
    uid_t   f_owner;		/* user that mounted the filesystem */
    int     f_type;		/* type of filesystem (see below) */
    int     f_flags;		/* copy of mount flags */
    long    f_spare[2];		/* spare for later */
    char    f_fstypename[MFSNAMELEN];/* fs type name */
    char    f_mntonname[MNAMELEN];/* directory on which mounted */
    char    f_mntfromname[MNAMELEN];/* mounted filesystem */
};
.Ed
.Pp
The flags that may be returned include:
.Bl -tag -width MNT_ASYNCHRONOUS
.It Dv MNT_RDONLY
The filesystem is mounted read-only;
Even the super-user may not write on it.
.It Dv MNT_NOEXEC
Files may not be executed from the filesystem.
.It Dv MNT_NOSUID
Setuid and setgid bits on files are not honored when they are executed.
.It Dv MNT_NODEV
Special files in the filesystem may not be opened.
.It Dv MNT_SYNCHRONOUS
All I/O to the filesystem is done synchronously.
.It Dv MNT_ASYNCHRONOUS
No filesystem I/O is done synchronously.
.It Dv MNT_LOCAL
The filesystem resides locally.
.It Dv MNT_QUOTA
The filesystem has quotas enabled on it.
.It Dv MNT_ROOTFS
Identifies the root filesystem.
.It Dv MNT_EXRDONLY
The filesystem is exported read-only.
.It Dv MNT_EXPORTED
The filesystem is exported for both reading and writing.
.It Dv MNT_DEFEXPORTED
The filesystem is exported for both reading and writing to any Internet host.
.It Dv MNT_EXPORTANON
The filesystem maps all remote accesses to the anonymous user.
.It Dv MNT_EXKERB
The filesystem is exported with Kerberos uid mapping.
.El
.Pp
Fields that are undefined for a particular filesystem are set to -1.
The buffer is filled with an array of
.Fa fsstat
structures, one for each mounted filesystem
up to the size specified by
.Fa bufsize .
.Pp
If
.Fa buf
is given as NULL,
.Fn getfsstat
returns just the number of mounted filesystems.
.Pp
Normally
.Fa flags
should be specified as
.Dv MNT_WAIT .
If
.Fa flags
is set to
.Dv MNT_NOWAIT ,
.Fn getfsstat
will return the information it has available without requesting
an update from each filesystem.
Thus, some of the information will be out of date, but
.Fn getfsstat
will not block waiting for information from a filesystem that is
unable to respond.
.Sh RETURN VALUES
Upon successful completion, the number of 
.Fa fsstat
structures is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn Getfsstat
fails if one or more of the following are true:
.Bl -tag -width Er
.It EFAULT
.Fa Buf
points to an invalid address.
.It EIO
An
.Tn I/O
error occurred while reading from or writing to the filesystem.
.El
.Sh SEE ALSO
.Xr statfs 2 ,
.Xr fstab 5 ,
.Xr mount 8
.Sh HISTORY
The
.Fn getfsstat
function first appeared in
.Bx 4.4 .