1.\" $NetBSD: rename.2,v 1.16 2002/02/08 01:28:21 ross Exp $ 2.\" 3.\" Copyright (c) 1983, 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)rename.2 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt RENAME 2 38.Os 39.Sh NAME 40.Nm rename 41.Nd change the name of a file 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]stdio.h\*[Gt] 46.Ft int 47.Fn rename "const char *from" "const char *to" 48.Sh DESCRIPTION 49.Fn rename 50causes the link named 51.Fa from 52to be renamed as 53.Fa to . 54If 55.Fa to 56exists, it is first removed. 57Both 58.Fa from 59and 60.Fa to 61must be of the same type (that is, both directories or both 62non-directories), and must reside on the same file system. 63.Pp 64.Fn rename 65guarantees that an instance of 66.Fa to 67will always exist, even if the system should crash in 68the middle of the operation. 69.Pp 70If the final component of 71.Fa from 72is a symbolic link, 73the symbolic link is renamed, 74not the file or directory to which it points. 75.Pp 76If both 77.Fa from 78and 79.Fa to 80are pathnames of the same existing file in the file system's name space, 81.Fn rename 82returns successfully and performs no other action. 83.Sh RETURN VALUES 84A 0 value is returned if the operation succeeds, otherwise 85.Fn rename 86returns -1 and the global variable 87.Va errno 88indicates the reason for the failure. 89.Sh ERRORS 90.Fn rename 91will fail and neither of the argument files will be 92affected if: 93.Bl -tag -width Er 94.It Bq Er ENAMETOOLONG 95A component of a pathname exceeded 96.Dv {NAME_MAX} 97characters, or an entire path name exceeded 98.Dv {PATH_MAX} 99characters. 100.It Bq Er ENOENT 101A component of the 102.Fa from 103path does not exist, 104or a path prefix of 105.Fa to 106does not exist. 107.It Bq Er EACCES 108A component of either path prefix denies search permission, or 109the requested link requires writing in a directory with a mode 110that denies write permission. 111.It Bq Er EPERM 112The directory containing 113.Fa from 114is marked sticky, 115and neither the containing directory nor 116.Fa from 117are owned by the effective user ID. 118Or the 119.Fa to 120file exists, 121the directory containing 122.Fa to 123is marked sticky, 124and neither the containing directory nor 125.Fa to 126are owned by the effective user ID. 127.It Bq Er ELOOP 128Too many symbolic links were encountered in translating either pathname. 129.It Bq Er ENOTDIR 130A component of either path prefix is not a directory, or 131.Fa from 132is a directory, but 133.Fa to 134is not a directory. 135.It Bq Er EISDIR 136.Fa to 137is a directory, but 138.Fa from 139is not a directory. 140.It Bq Er EXDEV 141The link named by 142.Fa to 143and the file named by 144.Fa from 145are on different logical devices (file systems). Note that this error 146code will not be returned if the implementation permits cross-device 147links. 148.It Bq Er ENOSPC 149The directory in which the entry for the new name is being placed 150cannot be extended because there is no space left on the file 151system containing the directory. 152.It Bq Er EDQUOT 153The directory in which the entry for the new name 154is being placed cannot be extended because the 155user's quota of disk blocks on the file system 156containing the directory has been exhausted. 157.It Bq Er EIO 158An I/O error occurred while making or updating a directory entry. 159.It Bq Er EROFS 160The requested link requires writing in a directory on a read-only file 161system. 162.It Bq Er EFAULT 163.Em Path 164points outside the process's allocated address space. 165.It Bq Er EINVAL 166.Fa from 167is a parent directory of 168.Fa to , 169or an attempt is made to rename 170.Ql \&. 171or 172.Ql \&.. . 173.It Bq Er ENOTEMPTY 174.Fa to 175is a directory and is not empty. 176.El 177.Sh SEE ALSO 178.Xr open 2 , 179.Xr symlink 7 180.Sh STANDARDS 181The 182.Fn rename 183function deviates from the semantics defined in 184.St -p1003.1-90 , 185which specifies that if both 186.Fa from 187and 188.Fa to 189.Em link 190to the same existing file, 191.Fn rename 192shall return successfully and performs no further action, whereas this 193implementation will remove the file specified by 194.Fa from 195unless both 196.Fa from 197and 198.Fa to 199are pathnames of the same file in the file system's name space. 200.Pp 201To retain conformance, a compatibility interface is provided by the 202.Lb libposix 203which is also be brought into scope if any of the 204.Dv _POSIX_SOURCE , 205.Dv _POSIX_C_SOURCE 206or 207.Dv _XOPEN_SOURCE 208preprocessor symbols are defined at compile-time: 209the 210.Fn rename 211function conforms to 212.St -p1003.1-90 213and 214.St -xpg4.2 . 215.Sh BUGS 216The system can deadlock if a loop in the file system graph is present. 217This loop takes the form of an entry in directory 218.Ql Pa a , 219say 220.Ql Pa a/foo , 221being a hard link to directory 222.Ql Pa b , 223and an entry in 224directory 225.Ql Pa b , 226say 227.Ql Pa b/bar , 228being a hard link 229to directory 230.Ql Pa a . 231When such a loop exists and two separate processes attempt to 232perform 233.Ql rename a/foo b/bar 234and 235.Ql rename b/bar a/foo , 236respectively, 237the system may deadlock attempting to lock 238both directories for modification. 239Hard links to directories should be 240replaced by symbolic links by the system administrator. 241