Index: head/lib/libc/sys/unlink.2
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--- head/lib/libc/sys/unlink.2	(revision 348706)
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@@ -1,289 +1,290 @@
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 .\"     @(#)unlink.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd April 6, 2019
+.Dd June 6, 2019
 .Dt UNLINK 2
 .Os
 .Sh NAME
 .Nm unlink ,
-.Nm unlinkat
+.Nm unlinkat ,
+.Nm funlinkat
 .Nd remove directory entry
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
 .In unistd.h
 .Ft int
 .Fn unlink "const char *path"
 .Ft int
 .Fn unlinkat "int dfd" "const char *path" "int flag"
 .Ft int
 .Fn funlinkat "int dfd" "const char *path" "int fd" "int flag"
 .Sh DESCRIPTION
 The
 .Fn unlink
 system call
 removes the link named by
 .Fa path
 from its directory and decrements the link count of the
 file which was referenced by the link.
 If that decrement reduces the link count of the file
 to zero,
 and no process has the file open, then
 all resources associated with the file are reclaimed.
 If one or more process have the file open when the last link is removed,
 the link is removed, but the removal of the file is delayed until
 all references to it have been closed.
 The
 .Fa path
 argument
 may not be a directory.
 .Pp
 The
 .Fn unlinkat
 system call is equivalent to
 .Fn unlink
 or
 .Fn rmdir
 except in the case where
 .Fa path
 specifies a relative path.
 In this case the directory entry to be removed is determined
 relative to the directory associated with the file descriptor
 .Fa dfd
 instead of the current working directory.
 .Pp
 The values for
 .Fa flag
 are constructed by a bitwise-inclusive OR of flags from the following list,
 defined in
 .In fcntl.h :
 .Bl -tag -width indent
 .It Dv AT_REMOVEDIR
 Remove the directory entry specified by
 .Fa fd
 and
 .Fa path
 as a directory, not a normal file.
 .It Dv AT_BENEATH
 Only unlink files and directories which are beneath of the topping
 directory.
 See the description of the
 .Dv O_BENEATH
 flag in the
 .Xr open 2
 manual page.
 .El
 .Pp
 If
 .Fn unlinkat
 is passed the special value
 .Dv AT_FDCWD
 in the
 .Fa fd
 parameter, the current working directory is used and the behavior is
 identical to a call to
 .Fa unlink
 or
 .Fa rmdir
 respectively, depending on whether or not the
 .Dv AT_REMOVEDIR
 bit is set in flag.
 .Pp
 The
 .Fn funlinkat
 system call can be used to unlink an already-opened file, unless that
 file has been replaced since it was opened.
 It is equivalent to
 .Fn unlinkat
 in the case where
 .Fa path
 is already open as the file descriptor
 .Fa fd .
 Otherwise, the path will not be removed and an error will be returned.
 The
 .Fa fd
 can be set the
 .Dv FD_NONE .
 In that case
 .Fn funlinkat
 behaves exactly like
 .Fn unlinkat .
 .Sh RETURN VALUES
 .Rv -std unlink
 .Sh ERRORS
 The
 .Fn unlink
 succeeds unless:
 .Bl -tag -width Er
 .It Bq Er ENOTDIR
 A component of the path prefix is not a directory.
 .It Bq Er EISDIR
 The named file is a directory.
 .It Bq Er ENAMETOOLONG
 A component of a pathname exceeded 255 characters,
 or an entire path name exceeded 1023 characters.
 .It Bq Er ENOENT
 The named file does not exist.
 .It Bq Er EACCES
 Search permission is denied for a component of the path prefix.
 .It Bq Er EACCES
 Write permission is denied on the directory containing the link
 to be removed.
 .It Bq Er ELOOP
 Too many symbolic links were encountered in translating the pathname.
 .It Bq Er EPERM
 The named file is a directory.
 .It Bq Er EPERM
 The named file has its immutable, undeletable or append-only flag set, see the
 .Xr chflags 2
 manual page for more information.
 .It Bq Er EPERM
 The parent directory of the named file has its immutable or append-only flag
 set.
 .It Bq Er EPERM
 The directory containing the file is marked sticky,
 and neither the containing directory nor the file to be removed
 are owned by the effective user ID.
 .It Bq Er EIO
 An I/O error occurred while deleting the directory entry
 or deallocating the inode.
 .It Bq Er EROFS
 The named file resides on a read-only file system.
 .It Bq Er EFAULT
 The
 .Fa path
 argument
 points outside the process's allocated address space.
 .It Bq Er ENOSPC
 On file systems supporting copy-on-write or snapshots, there was not enough
 free space to record metadata for the delete operation of the file.
 .El
 .Pp
 In addition to the errors returned by the
 .Fn unlink ,
 the
 .Fn unlinkat
 may fail if:
 .Bl -tag -width Er
 .It Bq Er EBADF
 The
 .Fa path
 argument does not specify an absolute path and the
 .Fa fd
 argument is neither
 .Dv AT_FDCWD
 nor a valid file descriptor open for searching.
 .It Bq Er ENOTEMPTY
 The
 .Fa flag
 parameter has the
 .Dv AT_REMOVEDIR
 bit set and the
 .Fa path
 argument names a directory that is not an empty directory,
 or there are hard links to the directory other than dot or
 a single entry in dot-dot.
 .It Bq Er ENOTDIR
 The
 .Fa flag
 parameter has the
 .Dv AT_REMOVEDIR
 bit set and
 .Fa path
 does not name a directory.
 .It Bq Er EINVAL
 The value of the
 .Fa flag
 argument is not valid.
 .It Bq Er ENOTDIR
 The
 .Fa path
 argument is not an absolute path and
 .Fa fd
 is neither
 .Dv AT_FDCWD
 nor a file descriptor associated with a directory.
 .It Bq Er ENOTCAPABLE
 .Fa path
 is an absolute path,
 or contained a ".." component leading to a
 directory outside of the directory hierarchy specified by
 .Fa fd ,
 and the process is in capability mode.
 .It Bq Er ENOTCAPABLE
 The
 .Dv AT_BENEATH
 flag was provided to
 .Fn unlinkat ,
 and the absolute
 .Fa path
 does not have its tail fully contained under the topping directory,
 or the relative
 .Fa path
 escapes it.
 .El
 .Pp
 In addition to the errors returned by
 .Fn unlinkat ,
 .Fn funlinkat
 may fail if:
 .Bl -tag -width Er
 .It Bq Er EDEADLK
 The file descriptor is not associated with the path.
 .El
 .Sh SEE ALSO
 .Xr chflags 2 ,
 .Xr close 2 ,
 .Xr link 2 ,
 .Xr rmdir 2 ,
 .Xr symlink 7
 .Sh STANDARDS
 The
 .Fn unlinkat
 system call follows The Open Group Extended API Set 2 specification.
 .Sh HISTORY
 The
 .Fn unlink
 function appeared in
 .At v1 .
 The
 .Fn unlinkat
 system call appeared in
 .Fx 8.0 .
 The
 .Fn funlinkat
 system call appeared in
 .Fx 13.0 .
 .Pp
 The
 .Fn unlink
 system call traditionally allows the super-user to unlink directories which
 can damage the file system integrity.
 This implementation no longer permits it.