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GETFSSTAT(2) System Calls Manual GETFSSTAT(2)

getfsstat, getvfsstatget list of all mounted filesystems

library “libc”

#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>

int
getfsstat(struct statfs *buf, long bufsize, int flags);

#include <sys/statvfs.h>

int
getvfsstat(struct statfs *buf, struct statvfs *vbuf, long vbufsize, int flags);

() returns information about all mounted filesystems. Buf is a pointer to statfs structures defined as follows:
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   80	/* 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_syncwrites;	/* count of sync writes since mount */
    long    f_asyncwrites;	/* count of async writes since mount */
    char    f_fstypename[MFSNAMELEN];/* fs type name */
    char    f_mntonname[MNAMELEN];/* directory on which mounted */
    long    f_syncreads;	/* count of sync reads since mount */
    long    f_asyncreads;	/* count of async reads since mount */
    short   f_spares1;		/* unused spare */
    char    f_mntfromname[MNAMELEN];/* mounted filesystem */
    short   f_spares2;		/* unused spare */
    long    f_spare[2];		/* unused spare */
};

The flags that may be returned include:

The filesystem is mounted read-only; Even the super-user may not write on it.
Files may not be executed from the filesystem.
Setuid and setgid bits on files are not honored when they are executed.
Special files in the filesystem may not be opened.
All I/O to the filesystem is done synchronously.
No filesystem I/O is done synchronously.
The filesystem resides locally.
The filesystem has quotas enabled on it.
Identifies the root filesystem.
The filesystem is exported read-only.
The filesystem is exported for both reading and writing.
The filesystem is exported for both reading and writing to any Internet host.
The filesystem maps all remote accesses to the anonymous user.
The filesystem is exported with Kerberos uid mapping.

Fields that are undefined for a particular filesystem are set to -1. The buffer is filled with an array of fsstat structures, one for each mounted filesystem up to the size specified by bufsize.

If buf is given as NULL, () returns just the number of mounted filesystems.

Normally flags should be specified as MNT_WAIT. If flags is set to MNT_NOWAIT, () 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 getfsstat() will not block waiting for information from a filesystem that is unable to respond. () returns extended information about all mounted filesystems. Note that vbufsize represents the size of vbuf, and buf is expected to be of contemporary size for its own structures.

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

Getfsstat() and getvfsstat() fail if one or more of the following are true:

[]
Buf points to an invalid address.
[]
An I/O error occurred while reading from or writing to the filesystem.

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

The getfsstat() function first appeared in 4.4BSD.

May 25, 1995 DragonFly-5.6.1