bsd/man/man2/getfsstat.2

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  34 .\"     @(#)getfsstat.2 8.1 (Berkeley) 6/9/93
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  36 .Dd June 9, 1993
  37 .Dt GETFSSTAT 2
  38 .Os
  39 .Sh NAME
  40 .Nm getfsstat
  41 .Nd get list of all mounted file systems
  42 .Sh SYNOPSIS
  43 .Fd #include <sys/param.h>
  44 .Fd #include <sys/ucred.h>
  45 .Fd #include <sys/mount.h>
  46 .Ft int
  47 .Fn getfsstat "struct statfs *buf" "long bufsize" "int flags"
  48 .Sh DESCRIPTION
  49 .Fn Getfsstat
  50 returns information about all mounted file systems.
  51 .Fa Buf
  52 is a pointer to an array of
  53 .Xr statfs
  54 structures defined as follows:
  55 .Bd -literal
  56 typedef struct { int32_t val[2]; } fsid_t;
  57
  58 #define MFSNAMELEN   16 /* length of fs type name, including nul */
  59 #define MNAMELEN     32 /* length of buffer for returned name */
  60
  61 struct statfs {
  62     short   f_type;     /* type of file system (unused; zero) */
  63     short   f_flags;    /* copy of mount flags */
  64     long    f_bsize;    /* fundamental file system block size */
  65     long    f_iosize;   /* optimal transfer block size */
  66     long    f_blocks;   /* total data blocks in file system */
  67     long    f_bfree;    /* free blocks in fs */
  68     long    f_bavail;   /* free blocks avail to non-superuser */
  69     long    f_files;    /* total file nodes in file system */
  70     long    f_ffree;    /* free file nodes in fs */
  71     fsid_t  f_fsid;     /* file system id */
  72     uid_t   f_owner;    /* user that mounted the file system */
  73     long    f_spare[4]; /* spare for later */
  74     char    f_fstypename[MFSNAMELEN]; /* fs type name */
  75     char    f_mntonname[MNAMELEN];    /* directory on which mounted */
  76     char    f_mntfromname[MNAMELEN];  /* mounted file system */
  77 };
  78 .Ed
  79 .Pp
  80 Fields that are undefined for a particular file system are set to -1.
  81 The buffer is filled with an array of
  82 .Fa statfs
  83 structures, one for each mounted file system
  84 up to the size specified by
  85 .Fa bufsize .
  86 .Pp
  87 If
  88 .Fa buf
  89 is given as NULL,
  90 .Fn getfsstat
  91 returns just the number of mounted file systems.
  92 .Pp
  93 Normally
  94 .Fa flags
  95 should be specified as
  96 .Dv MNT_WAIT .
  97 If
  98 .Fa flags
  99 is set to
 100 .Dv MNT_NOWAIT ,
 101 .Fn getfsstat
 102 will return the information it has available without requesting
 103 an update from each file system.
 104 Thus, some of the information will be out of date, but
 105 .Fn getfsstat
 106 will not block waiting for information from a file system that is
 107 unable to respond.
 108 .Sh RETURN VALUES
 109 Upon successful completion, the number of
 110 .Fa statfs
 111 structures is returned.
 112 Otherwise, -1 is returned and the global variable
 113 .Va errno
 114 is set to indicate the error.
 115 .Sh ERRORS
 116 .Fn Getfsstat
 117 fails if one or more of the following are true:
 118 .Bl -tag -width Er
 119 .It Bq Er EFAULT
 120 .Fa Buf
 121 points to an invalid address.
 122 .It Bq Er EIO
 123 An
 124 .Tn I/O
 125 error occurred while reading from or writing to the file system.
 126 .El
 127 .Sh SEE ALSO
 128 .Xr statfs 2 ,
 129 .Xr fstab 5 ,
 130 .Xr mount 8
 131 .Sh HISTORY
 132 The
 133 .Fn getfsstat
 134 function first appeared in 4.4BSD.