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Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)unlink.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd December 1, 2017 32.Dt UNLINK 2 33.Os 34.Sh NAME 35.Nm unlink , 36.Nm unlinkat 37.Nd remove directory entry 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft int 43.Fn unlink "const char *path" 44.Ft int 45.Fn unlinkat "int fd" "const char *path" "int flag" 46.Sh DESCRIPTION 47The 48.Fn unlink 49system call 50removes the link named by 51.Fa path 52from its directory and decrements the link count of the 53file which was referenced by the link. 54If that decrement reduces the link count of the file 55to zero, 56and no process has the file open, then 57all resources associated with the file are reclaimed. 58If one or more process have the file open when the last link is removed, 59the link is removed, but the removal of the file is delayed until 60all references to it have been closed. 61The 62.Fa path 63argument 64may not be a directory. 65.Pp 66The 67.Fn unlinkat 68system call is equivalent to 69.Fn unlink 70or 71.Fn rmdir 72except in the case where 73.Fa path 74specifies a relative path. 75In this case the directory entry to be removed is determined 76relative to the directory associated with the file descriptor 77.Fa fd 78instead of the current working directory. 79.Pp 80The values for 81.Fa flag 82are constructed by a bitwise-inclusive OR of flags from the following list, 83defined in 84.In fcntl.h : 85.Bl -tag -width indent 86.It Dv AT_REMOVEDIR 87Remove the directory entry specified by 88.Fa fd 89and 90.Fa path 91as a directory, not a normal file. 92.El 93.Pp 94If 95.Fn unlinkat 96is passed the special value 97.Dv AT_FDCWD 98in the 99.Fa fd 100parameter, the current working directory is used and the behavior is 101identical to a call to 102.Fa unlink 103or 104.Fa rmdir 105respectively, depending on whether or not the 106.Dv AT_REMOVEDIR 107bit is set in flag. 108.Sh RETURN VALUES 109.Rv -std unlink 110.Sh ERRORS 111The 112.Fn unlink 113succeeds unless: 114.Bl -tag -width Er 115.It Bq Er ENOTDIR 116A component of the path prefix is not a directory. 117.It Bq Er EISDIR 118The named file is a directory. 119.It Bq Er ENAMETOOLONG 120A component of a pathname exceeded 255 characters, 121or an entire path name exceeded 1023 characters. 122.It Bq Er ENOENT 123The named file does not exist. 124.It Bq Er EACCES 125Search permission is denied for a component of the path prefix. 126.It Bq Er EACCES 127Write permission is denied on the directory containing the link 128to be removed. 129.It Bq Er ELOOP 130Too many symbolic links were encountered in translating the pathname. 131.It Bq Er EPERM 132The named file is a directory. 133.It Bq Er EPERM 134The named file has its immutable, undeletable or append-only flag set, see the 135.Xr chflags 2 136manual page for more information. 137.It Bq Er EPERM 138The parent directory of the named file has its immutable or append-only flag 139set. 140.It Bq Er EPERM 141The directory containing the file is marked sticky, 142and neither the containing directory nor the file to be removed 143are owned by the effective user ID. 144.It Bq Er EIO 145An I/O error occurred while deleting the directory entry 146or deallocating the inode. 147.It Bq Er EROFS 148The named file resides on a read-only file system. 149.It Bq Er EFAULT 150The 151.Fa path 152argument 153points outside the process's allocated address space. 154.It Bq Er ENOSPC 155On file systems supporting copy-on-write or snapshots, there was not enough 156free space to record metadata for the delete operation of the file. 157.El 158.Pp 159In addition to the errors returned by the 160.Fn unlink , 161the 162.Fn unlinkat 163may fail if: 164.Bl -tag -width Er 165.It Bq Er EBADF 166The 167.Fa path 168argument does not specify an absolute path and the 169.Fa fd 170argument is neither 171.Dv AT_FDCWD 172nor a valid file descriptor open for searching. 173.It Bq Er ENOTEMPTY 174The 175.Fa flag 176parameter has the 177.Dv AT_REMOVEDIR 178bit set and the 179.Fa path 180argument names a directory that is not an empty directory, 181or there are hard links to the directory other than dot or 182a single entry in dot-dot. 183.It Bq Er ENOTDIR 184The 185.Fa flag 186parameter has the 187.Dv AT_REMOVEDIR 188bit set and 189.Fa path 190does not name a directory. 191.It Bq Er EINVAL 192The value of the 193.Fa flag 194argument is not valid. 195.It Bq Er ENOTDIR 196The 197.Fa path 198argument is not an absolute path and 199.Fa fd 200is neither 201.Dv AT_FDCWD 202nor a file descriptor associated with a directory. 203.El 204.Sh SEE ALSO 205.Xr chflags 2 , 206.Xr close 2 , 207.Xr link 2 , 208.Xr rmdir 2 , 209.Xr symlink 7 210.Sh STANDARDS 211The 212.Fn unlinkat 213system call follows The Open Group Extended API Set 2 specification. 214.Sh HISTORY 215The 216.Fn unlink 217function appeared in 218.At v1 . 219The 220.Fn unlinkat 221system call appeared in 222.Fx 8.0 . 223.Pp 224The 225.Fn unlink 226system call traditionally allows the super-user to unlink directories which 227can damage the file system integrity. 228This implementation no longer permits it. 229