1.\" $NetBSD: unlink.2,v 1.30 2019/09/02 00:09:14 sevan Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)unlink.2 8.1 (Berkeley) 6/4/93 31.\" 32.Dd September 2, 2019 33.Dt UNLINK 2 34.Os 35.Sh NAME 36.Nm unlink , 37.Nm unlinkat 38.Nd remove directory entry 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In unistd.h 43.Ft int 44.Fn unlink "const char *path" 45.In fcntl.h 46.Ft int 47.Fn unlinkat "int fd" "const char *path" "int flag" 48.Sh DESCRIPTION 49The 50.Fn unlink 51function 52removes the link named by 53.Fa path 54from its directory and decrements the link count of the 55file which was referenced by the link. 56If that decrement reduces the link count of the file 57to zero, 58and no process has the file open, then 59all resources associated with the file are reclaimed. 60If one or more process have the file open when the last link is removed, 61the link is removed, but the removal of the file is delayed until 62all references to it have been closed. 63.Pp 64.Fn unlinkat 65works the same way as 66.Fn unlink 67except if 68.Fa path 69is relative. 70In that case, it is looked up from a directory whose file 71descriptor was passed as 72.Fa fd . 73Search permission is required on this directory. 74.\" (These alternatives await a decision about the semantics of O_SEARCH) 75.\" Search permission is required on this directory 76.\" except if 77.\" .Fa fd 78.\" was opened with the 79.\" .Dv O_SEARCH 80.\" flag. 81.\" - or - 82.\" This file descriptor must have been opened with the 83.\" .Dv O_SEARCH 84.\" flag. 85.Fa fd 86can be set to 87.Dv AT_FDCWD 88in order to specify the current directory. 89.Pp 90.Fn unlinkat 91will remove directories just like 92.Xr rmdir 2 , 93provided 94.Dv AT_REMOVEDIR 95is set in 96.Fa flag . 97.Sh RETURN VALUES 98.Rv -std unlink unlinkat 99.Sh ERRORS 100The 101.Fn unlink 102and 103.Fn unlinkat 104functions succeed unless: 105.Bl -tag -width Er 106.It Bq Er EACCES 107Search permission is denied for a component of the path prefix, or 108write permission is denied on the directory containing the link 109to be removed. 110.It Bq Er EBUSY 111The entry to be unlinked is the mount point for a 112mounted file system. 113.It Bq Er EFAULT 114.Fa path 115points outside the process's allocated address space. 116.It Bq Er EIO 117An I/O error occurred while deleting the directory entry 118or deallocating the inode. 119.It Bq Er ELOOP 120Too many symbolic links were encountered in translating the pathname. 121.It Bq Er ENAMETOOLONG 122A component of a pathname exceeded 123.Brq Dv NAME_MAX 124characters, or an entire path name exceeded 125.Brq Dv PATH_MAX 126characters. 127.It Bq Er ENOENT 128The named file does not exist. 129.It Bq Er ENOTDIR 130A component of the path prefix is not a directory. 131.It Bq Er EPERM 132The named file is a directory and the effective user ID 133of the process is not the super-user, the file system 134containing the file does not permit the use of 135.Fn unlink 136on a directory, 137or the directory containing the file is marked sticky, 138and neither the containing directory nor the file to be removed 139are owned by the effective user ID. 140.It Bq Er EROFS 141The named file resides on a read-only file system. 142.El 143.Pp 144In addition, 145.Fn unlinkat 146will fail if: 147.Bl -tag -width Er 148.It Bq Er EBADF 149.Fa path 150does not specify an absolute path and 151.Fa fd 152is neither 153.Dv AT_FDCWD 154nor a valid file descriptor open for reading or searching. 155.It Bq Er ENOTDIR 156.Fa path 157is not an absolute path and 158.Fa fd 159is a file descriptor associated with a non-directory file; or 160.Fa flag 161has 162.Dv AT_REMOVEDIR 163set and 164.Fa path 165does not name a directory. 166.It Bq Er ENOTEMPTY 167.Fa flag 168has 169.Dv AT_REMOVEDIR 170set and 171.Fa path 172is a directory that is not empty. 173.El 174.Sh SEE ALSO 175.Xr close 2 , 176.Xr link 2 , 177.Xr rmdir 2 , 178.Xr symlink 7 179.Sh STANDARDS 180The 181.Fn unlink 182function conforms to 183.St -p1003.1-90 . 184.Fn unlinkat 185conforms to 186.St -p1003.1-2008 . 187.Sh HISTORY 188An 189.Fn unlink 190function call appeared in 191.At v1 . 192