rename.2: srcfix

[thirdparty/man-pages.git] / man2 / rename.2

.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\"             and Copyright (C) 1993 Michael Haardt;
.\"             and Copyright (C) 1993,1995 Ian Jackson
.\"		and Copyright (C) 2006, 2014 Michael Kerrisk
.\"
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.\" Modified Sat Jul 24 00:35:52 1993 by Rik Faith <faith@cs.unc.edu>
.\" Modified Thu Jun  4 12:21:13 1998 by Andries Brouwer <aeb@cwi.nl>
.\" Modified Thu Mar  3 09:49:35 2005 by Michael Haardt <michael@moria.de>
.\" 2007-03-25, mtk, added various text to DESCRIPTION.
.\"
.TH RENAME 2 2014-04-19 "Linux" "Linux Programmer's Manual"
.SH NAME
rename, renameat, renameat2 \- change the name or location of a file
.SH SYNOPSIS
.nf
.B #include <stdio.h>
.sp
.BI "int rename(const char *" oldpath ", const char *" newpath );
.sp
.BR "#include <fcntl.h>           " "/* Definition of AT_* constants */"
.B #include <stdio.h>
.sp
.BI "int renameat(int " olddirfd ", const char *" oldpath ,
.BI "             int " newdirfd ", const char *" newpath );

.BI "int renameat2(int " olddirfd ", const char *" oldpath ,
.BI "              int " newdirfd ", const char *" newpath \
", unsigned int " flags );
.fi
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.BR renameat ():
.PD 0
.ad l
.RS 4
.TP 4
Since glibc 2.10:
_XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
.TP
Before glibc 2.10:
_ATFILE_SOURCE
.\" FIXME need to define FTMs for renameat2(), once it hits glibc
.RE
.ad
.PD
.SH DESCRIPTION
.BR rename ()
renames a file, moving it between directories if required.
Any other hard links to the file (as created using
.BR link (2))
are unaffected.
Open file descriptors for
.I oldpath
are also unaffected.

If
.I newpath
already exists, it will be atomically replaced (subject to
a few conditions; see ERRORS below), so that there is
no point at which another process attempting to access
.I newpath
will find it missing.

If
.I oldpath
and
.I newpath
are existing hard links referring to the same file, then
.BR rename ()
does nothing, and returns a success status.

If
.I newpath
exists but the operation fails for some reason,
.BR rename ()
guarantees to leave an instance of
.I newpath
in place.

.I oldpath
can specify a directory.
In this case,
.I newpath
must either not exist, or it must specify an empty directory.

However, when overwriting there will probably be a window in which
both
.I oldpath
and
.I newpath
refer to the file being renamed.

If
.I oldpath
refers to a symbolic link, the link is renamed; if
.I newpath
refers to a symbolic link, the link will be overwritten.
.SS renameat ()
The
.BR renameat ()
system call operates in exactly the same way as
.BR rename (),
except for the differences described here.

If the pathname given in
.I oldpath
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
.I olddirfd
(rather than relative to the current working directory of
the calling process, as is done by
.BR rename ()
for a relative pathname).

If
.I oldpath
is relative and
.I olddirfd
is the special value
.BR AT_FDCWD ,
then
.I oldpath
is interpreted relative to the current working
directory of the calling process (like
.BR rename ()).

If
.I oldpath
is absolute, then
.I olddirfd
is ignored.

The interpretation of
.I newpath
is as for
.IR oldpath ,
except that a relative pathname is interpreted relative
to the directory referred to by the file descriptor
.IR newdirfd .

See
.BR openat (2)
for an explanation of the need for
.BR renameat ().
.SS renameat2()
.BR renameat2 ()
has an additional
.I flags
argument.
A
.BR renameat2 ()
call with a zero
.I flags
argument is equivalent to
.BR renameat ().

The
.I flags
argument is a bit mask consisting of zero or more of the following flags:
.TP
.B RENAME_NOREPLACE
Don't overwrite
.IR newpath .
of the rename.
Return an error if
.IR newpath
already exists.
.TP
.B RENAME_EXCHANGE
Atomically exchange
.IR oldpath
and
.IR newpath .
Both pathnames must exist
but may be of different types (e.g., one could be a non-empty directory
and the other a symbolic link).
.SH RETURN VALUE
On success, zero is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EACCES
Write permission is denied for the directory containing
.I oldpath
or
.IR newpath ,
or, search permission is denied for one of the directories
in the path prefix of
.I oldpath
or
.IR newpath ,
or
.I oldpath
is a directory and does not allow write permission (needed to update
the
.I ..
entry).
(See also
.BR path_resolution (7).)
.TP
.B EBUSY
The rename fails because
.IR oldpath " or " newpath
is a directory that is in use by some process (perhaps as
current working directory, or as root directory, or because
it was open for reading) or is in use by the system
(for example as mount point), while the system considers
this an error.
(Note that there is no requirement to return
.B EBUSY
in such
cases\(emthere is nothing wrong with doing the rename anyway\(embut
it is allowed to return
.B EBUSY
if the system cannot otherwise
handle such situations.)
.TP
.B EDQUOT
The user's quota of disk blocks on the filesystem has been exhausted.
.TP
.B EFAULT
.IR oldpath " or " newpath " points outside your accessible address space."
.TP
.B EINVAL
The new pathname contained a path prefix of the old, or, more generally,
an attempt was made to make a directory a subdirectory of itself.
.TP
.B EISDIR
.I newpath
is an existing directory, but
.I oldpath
is not a directory.
.TP
.B ELOOP
Too many symbolic links were encountered in resolving
.IR oldpath " or " newpath .
.TP
.B EMLINK
.I oldpath
already has the maximum number of links to it, or
it was a directory and the directory containing
.I newpath
has the maximum number of links.
.TP
.B ENAMETOOLONG
.IR oldpath " or " newpath " was too long."
.TP
.B ENOENT
The link named by
.I oldpath
does not exist;
or, a directory component in
.I newpath
does not exist;
or,
.I oldpath
or
.I newpath
is an empty string.
.TP
.B ENOMEM
Insufficient kernel memory was available.
.TP
.B ENOSPC
The device containing the file has no room for the new directory
entry.
.TP
.B ENOTDIR
A component used as a directory in
.IR oldpath " or " newpath
is not, in fact, a directory.
Or,
.I oldpath
is a directory, and
.I newpath
exists but is not a directory.
.TP
.BR ENOTEMPTY " or " EEXIST
.I newpath
is a nonempty directory, that is, contains entries other than "." and "..".
.TP
.BR EPERM " or " EACCES
The directory containing
.I oldpath
has the sticky bit
.RB ( S_ISVTX )
set and the process's effective user ID is neither
the user ID of the file to be deleted nor that of the directory
containing it, and the process is not privileged
(Linux: does not have the
.B CAP_FOWNER
capability);
or
.I newpath
is an existing file and the directory containing it has the sticky bit set
and the process's effective user ID is neither the user ID of the file
to be replaced nor that of the directory containing it,
and the process is not privileged
(Linux: does not have the
.B CAP_FOWNER
capability);
or the filesystem containing
.I pathname
does not support renaming of the type requested.
.TP
.B EROFS
The file is on a read-only filesystem.
.TP
.B EXDEV
.IR oldpath " and " newpath
are not on the same mounted filesystem.
(Linux permits a filesystem to be mounted at multiple points, but
.BR rename ()
does not work across different mount points,
even if the same filesystem is mounted on both.)
.PP
The following additional errors can occur for
.BR renameat ()
and
.BR renameat2 ():
.TP
.B EBADF
.I olddirfd
or
.I newdirfd
is not a valid file descriptor.
.TP
.B ENOTDIR
.I oldpath
is relative and
.I olddirfd
is a file descriptor referring to a file other than a directory;
or similar for
.I newpath
and
.I newdirfd
.PP
The following additional errors can occur for
.BR renameat2 ():
.TP
.B EEXIST
.I flags
contains
.B RENAME_NOREPLACE
and
.I newpath
already exists.
.TP 
.B EINVAL
An invalid flag was specified in
.IR flags ,
or both
.B RENAME_NOREPLACE
and
.B RENAME_EXCHANGE
were specified.
.TP
.B EINVAL
The filesystem does not support one of the flags in
.IR flags .
.TP
.B ENOENT
.I flags
contains
.B RENAME_EXCHANGE
and
.IR newpath
does not exist.
.SH VERSIONS
.BR renameat ()
was added to Linux in kernel 2.6.16;
library support was added to glibc in version 2.4.

.BR renameat2 ()
was added to Linux in kernel 3.15.
.\" FIXME glibc support is pending.
.SH CONFORMING TO
.BR rename ():
4.3BSD, C89, C99, POSIX.1-2001, POSIX.1-2008.

.BR renameat ():
POSIX.1-2008.

.BR renameat2()
is Linux-specific.
.SH BUGS
On NFS filesystems, you can not assume that if the operation
failed, the file was not renamed.
If the server does the rename operation
and then crashes, the retransmitted RPC which will be processed when the
server is up again causes a failure.
The application is expected to
deal with this.
See
.BR link (2)
for a similar problem.
.SH SEE ALSO
.BR mv (1),
.BR chmod (2),
.BR link (2),
.BR symlink (2),
.BR unlink (2),
.BR path_resolution (7),
.BR symlink (7)