20e91ca36a
with the reasoning that the flags did not worked properly, and were not shipped in a release. O_RESOLVE_BENEATH is kept as useful. Reviewed by: markj Tested by: arichardson, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D28907
224 lines
5.1 KiB
Groff
224 lines
5.1 KiB
Groff
.\" Copyright (c) 1989, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\" Copyright (c) 2018 Gandi
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)getfh.2 8.1 (Berkeley) 6/9/93
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.\" $FreeBSD$
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.\"
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.Dd February 23, 2021
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.Dt GETFH 2
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.Os
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.Sh NAME
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.Nm getfh ,
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.Nm lgetfh ,
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.Nm getfhat
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.Nd get file handle
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/mount.h
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.Ft int
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.Fn getfh "const char *path" "fhandle_t *fhp"
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.Ft int
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.Fn lgetfh "const char *path" "fhandle_t *fhp"
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.Ft int
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.Fn getfhat "int fd" "const char *path" "fhandle_t *fhp" "int flag"
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.Sh DESCRIPTION
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The
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.Fn getfh
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system call
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returns a file handle for the specified file or directory
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in the file handle pointed to by
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.Fa fhp .
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.Pp
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The
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.Fn lgetfh
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system call is like
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.Fn getfh
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except in the case where the named file is a symbolic link,
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in which case
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.Fn lgetfh
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returns information about the link,
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while
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.Fn getfh
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returns information about the file the link references.
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.Pp
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The
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.Fn getfhat
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system call is equivalent to
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.Fn getfh
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and
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.Fn lgetfh
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except when the
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.Fa path
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specifies a relative path.
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For
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.Fn getfhat
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and relative
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.Fa path ,
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the status is retrieved from a file relative to
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the directory associated with the file descriptor
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.Fa fd
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instead of the current working directory.
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.Pp
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The values for the
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.Fa flag
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are constructed by a bitwise-inclusive OR of flags from this list,
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defined in
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.In fcntl.h :
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.Bl -tag -width indent
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.It Dv AT_SYMLINK_NOFOLLOW
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If
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.Fa path
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names a symbolic link, the status of the symbolic link is returned.
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.It Dv AT_RESOLVE_BENEATH
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Only walk paths below the directory specified by the
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.Ar fd
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descriptor.
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See the description of the
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.Dv O_RESOLVE_BENEATH
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flag in the
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.Xr open 2
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manual page.
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.El
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.Pp
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If
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.Fn getfhat
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is passed the special value
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.Dv AT_FDCWD
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in the
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.Fa fd
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parameter, the current working directory is used and the behavior is
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identical to a call to
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.Fn getfth
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or
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.Fn lgetfh
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respectively, depending on whether or not the
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.Dv AT_SYMLINK_NOFOLLOW
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bit is set in
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.Fa flag .
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.Pp
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When
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.Fn getfhat
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is called with an absolute
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.Fa path ,
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it ignores the
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.Fa fd
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argument.
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These system calls are restricted to the superuser.
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.Sh RETURN VALUES
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.Rv -std
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.Sh ERRORS
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The
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.Fn getfh
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and
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.Fn lgetfh
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system calls
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fail if one or more of the following are true:
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.Bl -tag -width Er
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.It Bq Er ENOTDIR
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A component of the path prefix of
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.Fa path
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is not a directory.
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.It Bq Er ENAMETOOLONG
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The length of a component of
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.Fa path
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exceeds 255 characters,
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or the length of
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.Fa path
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exceeds 1023 characters.
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.It Bq Er ENOENT
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The file referred to by
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.Fa path
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does not exist.
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix of
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.Fa path .
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating
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.Fa path .
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.It Bq Er EFAULT
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The
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.Fa fhp
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argument
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points to an invalid address.
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.It Bq Er EFAULT
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The
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.Fa path
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argument
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points to an invalid address.
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.It Bq Er EIO
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An
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.Tn I/O
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error occurred while reading from or writing to the file system.
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.It Bq Er EINTEGRITY
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Corrupted data was detected while reading from the file system.
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.It Bq Er ESTALE
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The file handle
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.Fa fhp
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is no longer valid.
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.El
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.Pp
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In addition to the errors returned by
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.Fn getfh ,
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and
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.Fn lgetfh ,
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the
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.Fn getfhat
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system call may fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa path
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argument does not specify an absolute path and the
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.Fa fd
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argument, is neither
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.Dv AT_FDCWD
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nor a valid file descriptor open for searching.
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.It Bq Er EINVAL
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The value of the
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.Fa flag
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argument is not valid.
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.It Bq Er ENOTDIR
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The
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.Fa path
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argument is not an absolute path and
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.Fa fd
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is neither
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.Dv AT_FDCWD
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nor a file descriptor associated with a directory.
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.Sh SEE ALSO
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.Xr fhopen 2 ,
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.Xr open 2 ,
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.Xr stat 2
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.Sh HISTORY
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The
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.Fn getfh
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system call first appeared in
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.Bx 4.4 .
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