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" "int 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   15 /* length of fs type name, not inc. nul */
  59 #define MNAMELEN     90 /* length of buffer for returned name */
  60
  61 struct statfs {
  62     short   f_otype;    /* type of file system (reserved: zero) */
  63     short   f_oflags;   /* copy of mount flags (reserved: zero) */
  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 (super-user only) */
  72     uid_t   f_owner;    /* user that mounted the file system */
  73     short   f_reserved1;        /* reserved for future use */
  74     short   f_type;     /* type of file system (reserved) */
  75     long    f_flags;    /* copy of mount flags (reserved) */
  76     long    f_reserved2[2];     /* reserved for future use */
  77     char    f_fstypename[MFSNAMELEN]; /* fs type name */
  78     char    f_mntonname[MNAMELEN];    /* directory on which mounted */
  79     char    f_mntfromname[MNAMELEN];  /* mounted file system */
  80     char    f_reserved3;        /* reserved for future use */
  81     long    f_reserved4[4];     /* reserved for future use */
  82 };
  83 .Ed
  84 .Pp
  85 Fields that are undefined for a particular file system are set to -1.
  86 The buffer is filled with an array of
  87 .Fa statfs
  88 structures, one for each mounted file system
  89 up to the size specified by
  90 .Fa bufsize .
  91 .Pp
  92 If
  93 .Fa buf
  94 is given as NULL,
  95 .Fn getfsstat
  96 returns just the number of mounted file systems.
  97 .Pp
  98 If
  99 .Fa flags
 100 is set to
 101 .Dv MNT_NOWAIT ,
 102 .Fn getfsstat
 103 will directly return the information retained in the kernel
 104 to avoid delays caused by waiting for updated information from
 105 a file system that is perhaps temporarily unable to respond.
 106 Some of the information returned may be out of date, however; if
 107 .Fa flags
 108 is set to
 109 .Dv MNT_WAIT
 110 instead,
 111 .Fn getfsstat
 112 will request updated information from each mounted filesystem before
 113 returning.
 114 .Sh RETURN VALUES
 115 Upon successful completion, the number of
 116 .Fa statfs
 117 structures is returned.
 118 Otherwise, -1 is returned and the global variable
 119 .Va errno
 120 is set to indicate the error.
 121 .Sh ERRORS
 122 .Fn Getfsstat
 123 fails if one or more of the following are true:
 124 .Bl -tag -width Er
 125 .It Bq Er EFAULT
 126 .Fa Buf
 127 points to an invalid address.
 128 .It Bq Er EIO
 129 An
 130 .Tn I/O
 131 error occurred while reading from or writing to the file system.
 132 .El
 133 .Sh SEE ALSO
 134 .Xr statfs 2 ,
 135 .Xr fstab 5 ,
 136 .Xr mount 8
 137 .Sh HISTORY
 138 The
 139 .Fn getfsstat
 140 function first appeared in 4.4BSD.