1.\" $NetBSD: rename.2,v 1.13 2001/05/17 23:45:24 matt 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 <stdio.h> 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 CAVEAT 84The system can deadlock if a loop in the file system graph is present. 85This loop takes the form of an entry in directory 86.Ql Pa a , 87say 88.Ql Pa a/foo , 89being a hard link to directory 90.Ql Pa b , 91and an entry in 92directory 93.Ql Pa b , 94say 95.Ql Pa b/bar , 96being a hard link 97to directory 98.Ql Pa a . 99When such a loop exists and two separate processes attempt to 100perform 101.Ql rename a/foo b/bar 102and 103.Ql rename b/bar a/foo , 104respectively, 105the system may deadlock attempting to lock 106both directories for modification. 107Hard links to directories should be 108replaced by symbolic links by the system administrator. 109.Sh RETURN VALUES 110A 0 value is returned if the operation succeeds, otherwise 111.Fn rename 112returns -1 and the global variable 113.Va errno 114indicates the reason for the failure. 115.Sh ERRORS 116.Fn rename 117will fail and neither of the argument files will be 118affected if: 119.Bl -tag -width Er 120.It Bq Er ENAMETOOLONG 121A component of a pathname exceeded 122.Dv {NAME_MAX} 123characters, or an entire path name exceeded 124.Dv {PATH_MAX} 125characters. 126.It Bq Er ENOENT 127A component of the 128.Fa from 129path does not exist, 130or a path prefix of 131.Fa to 132does not exist. 133.It Bq Er EACCES 134A component of either path prefix denies search permission, or 135the requested link requires writing in a directory with a mode 136that denies write permission. 137.It Bq Er EPERM 138The directory containing 139.Fa from 140is marked sticky, 141and neither the containing directory nor 142.Fa from 143are owned by the effective user ID. 144Or the 145.Fa to 146file exists, 147the directory containing 148.Fa to 149is marked sticky, 150and neither the containing directory nor 151.Fa to 152are owned by the effective user ID. 153.It Bq Er ELOOP 154Too many symbolic links were encountered in translating either pathname. 155.It Bq Er ENOTDIR 156A component of either path prefix is not a directory, or 157.Fa from 158is a directory, but 159.Fa to 160is not a directory. 161.It Bq Er EISDIR 162.Fa to 163is a directory, but 164.Fa from 165is not a directory. 166.It Bq Er EXDEV 167The link named by 168.Fa to 169and the file named by 170.Fa from 171are on different logical devices (file systems). Note that this error 172code will not be returned if the implementation permits cross-device 173links. 174.It Bq Er ENOSPC 175The directory in which the entry for the new name is being placed 176cannot be extended because there is no space left on the file 177system containing the directory. 178.It Bq Er EDQUOT 179The directory in which the entry for the new name 180is being placed cannot be extended because the 181user's quota of disk blocks on the file system 182containing the directory has been exhausted. 183.It Bq Er EIO 184An I/O error occurred while making or updating a directory entry. 185.It Bq Er EROFS 186The requested link requires writing in a directory on a read-only file 187system. 188.It Bq Er EFAULT 189.Em Path 190points outside the process's allocated address space. 191.It Bq Er EINVAL 192.Fa from 193is a parent directory of 194.Fa to , 195or an attempt is made to rename 196.Ql \&. 197or 198.Ql \&.. . 199.It Bq Er ENOTEMPTY 200.Fa to 201is a directory and is not empty. 202.El 203.Sh SEE ALSO 204.Xr open 2 , 205.Xr symlink 7 206.Sh STANDARDS 207The 208.Fn rename 209function deviates from the semantics defined in 210.St -p1003.1-90 , 211which specifies that if both 212.Fa from 213and 214.Fa to 215.Em link 216to the same existing file, 217.Fn rename 218shall return successfully and performs no further action, whereas this 219implementation will remove the file specified by 220.Fa from 221unless both 222.Fa from 223and 224.Fa to 225are pathnames of the same file in the file system's name space. 226.Pp 227To retain conformance, a compatibility interface is provided by the 228.Lb libposix 229which is also be brought into scope if any of the 230.Dv _POSIX_SOURCE , 231.Dv _POSIX_C_SOURCE 232or 233.Dv _XOPEN_SOURCE 234preprocessor symbols are defined at compile-time: 235the 236.Fn rename 237function conforms to 238.St -p1003.1-90 239and 240.St -xpg4.2 . 241