GETFSSTAT(2)

NAME
getfsstat - get list of all mounted file systems

SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
int
getfsstat(struct statfs *buf, size_t bufsize, int flags);

DESCRIPTION
getfsstat() returns information about all mounted file systems. buf is a pointer to an array of statfs(2) structures defined as follows:

    typedef struct { int32_t val[2]; } fsid_t;
    #define MFSNAMELEN   16 /* length of fs type name, including nul */
    #define MNAMELEN     90	/* length of buffer for returned name */
    struct statfs {
        u_int32_t  f_flags;	/* copy of mount flags */
        u_int32_t  f_bsize;	/* file system block size */
        u_int32_t  f_iosize;	/* optimal transfer block size */
        				/* unit is f_bsize */
        u_int64_t  f_blocks;	/* total data blocks in file system */
        u_int64_t  f_bfree;	/* free blocks in fs */
        int64_t    f_bavail;	/* free blocks avail to non-superuser */
        u_int64_t  f_files;	/* total file nodes in file system */
        u_int64_t  f_ffree;	/* free file nodes in fs */
        int64_t    f_favail;	/* free file nodes avail to non-root */
        u_int64_t  f_syncwrites;	/* count of sync writes since mount */
        u_int64_t  f_syncreads;	/* count of sync reads since mount */
        u_int64_t  f_asyncwrites;	/* count of async writes since mount */
        u_int64_t  f_asyncreads;	/* count of async reads since mount */
        fsid_t     f_fsid;		/* file system id */
        u_int32_t  f_namemax;	/* maximum filename length */
        uid_t      f_owner;	/* user that mounted the file system */
        u_int32_t  f_ctime;	/* last mount [-u] time */
        u_int32_t  f_spare[3];	/* spare for later */
        char f_fstypename[MFSNAMELEN];	/* fs type name */
        char f_mntonname[MNAMELEN];	/* directory on which mounted */
        char f_mntfromname[MNAMELEN];	/* mounted file system */
        union mount_info mount_info;	/* per-filesystem mount options */
    };

The buffer is filled with an array of statfs structures, one for each mounted file system up to the size specified by bufsize.

If buf is NULL, getfsstat() returns just the number of mounted file systems.

Normally flags should be specified as MNT_WAIT. If flags is set to MNT_NOWAIT, getfsstat() will return the information it has available without requesting an update from each file system. Thus, some of the information will be out of date, but getfsstat() will not block waiting for information from a file system that is unable to respond. If no flags are provided, MNT_WAIT is assumed.

Note that f_fsid will be empty unless the user is the superuser.

RETURN VALUES
Upon successful completion, the number of statfs structures is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
getfsstat() fails if one or more of the following are true:

[EFAULT]
    buf points to an invalid address.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

SEE ALSO
statfs(2), fstab(5), mount(8)

HISTORY
The getfsstat() function first appeared in 4.4BSD.