RENAME
Section: Linux Programmer's Manual (2)
Updated: 2014-08-19
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NAME
rename, renameat, renameat2 - change the name or location of a file
SYNOPSIS
#include <stdio.h>
int rename(const char *oldpath, const char *newpath);
#include <fcntl.h> /* Definition of AT_* constants */
#include <stdio.h>
int renameat(int olddirfd, const char *oldpath,
int newdirfd, const char *newpath);
int renameat2(int olddirfd, const char *oldpath,
int newdirfd, const char *newpath, unsigned int flags);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
renameat():
-
- Since glibc 2.10:
-
_XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
- Before glibc 2.10:
-
_ATFILE_SOURCE
DESCRIPTION
rename()
renames a file, moving it between directories if required.
Any other hard links to the file (as created using
link(2))
are unaffected.
Open file descriptors for
oldpath
are also unaffected.
If
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
newpath
will find it missing.
If
oldpath
and
newpath
are existing hard links referring to the same file, then
rename()
does nothing, and returns a success status.
If
newpath
exists but the operation fails for some reason,
rename()
guarantees to leave an instance of
newpath
in place.
oldpath
can specify a directory.
In this case,
newpath
must either not exist, or it must specify an empty directory.
However, when overwriting there will probably be a window in which
both
oldpath
and
newpath
refer to the file being renamed.
If
oldpath
refers to a symbolic link, the link is renamed; if
newpath
refers to a symbolic link, the link will be overwritten.
renameat()
The
renameat()
system call operates in exactly the same way as
rename(),
except for the differences described here.
If the pathname given in
oldpath
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
olddirfd
(rather than relative to the current working directory of
the calling process, as is done by
rename()
for a relative pathname).
If
oldpath
is relative and
olddirfd
is the special value
AT_FDCWD,
then
oldpath
is interpreted relative to the current working
directory of the calling process (like
rename()).
If
oldpath
is absolute, then
olddirfd
is ignored.
The interpretation of
newpath
is as for
oldpath,
except that a relative pathname is interpreted relative
to the directory referred to by the file descriptor
newdirfd.
See
openat(2)
for an explanation of the need for
renameat().
renameat2()
renameat2()
has an additional
flags
argument.
A
renameat2()
call with a zero
flags
argument is equivalent to
renameat().
The
flags
argument is a bit mask consisting of zero or more of the following flags:
- RENAME_NOREPLACE
-
Don't overwrite
newpath.
of the rename.
Return an error if
newpath
already exists.
- RENAME_EXCHANGE
-
Atomically exchange
oldpath
and
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).
RETURN VALUE
On success, zero is returned.
On error, -1 is returned, and
errno
is set appropriately.
ERRORS
- EACCES
-
Write permission is denied for the directory containing
oldpath
or
newpath,
or, search permission is denied for one of the directories
in the path prefix of
oldpath
or
newpath,
or
oldpath
is a directory and does not allow write permission (needed to update
the
..
entry).
(See also
path_resolution(7).)
- EBUSY
-
The rename fails because
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
EBUSY
in such
cases---there is nothing wrong with doing the rename anyway---but
it is allowed to return
EBUSY
if the system cannot otherwise
handle such situations.)
- EDQUOT
-
The user's quota of disk blocks on the filesystem has been exhausted.
- EFAULT
-
oldpath or newpath points outside your accessible address space.
- 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.
- EISDIR
-
newpath
is an existing directory, but
oldpath
is not a directory.
- ELOOP
-
Too many symbolic links were encountered in resolving
oldpath or newpath.
- EMLINK
-
oldpath
already has the maximum number of links to it, or
it was a directory and the directory containing
newpath
has the maximum number of links.
- ENAMETOOLONG
-
oldpath or newpath was too long.
- ENOENT
-
The link named by
oldpath
does not exist;
or, a directory component in
newpath
does not exist;
or,
oldpath
or
newpath
is an empty string.
- ENOMEM
-
Insufficient kernel memory was available.
- ENOSPC
-
The device containing the file has no room for the new directory
entry.
- ENOTDIR
-
A component used as a directory in
oldpath or newpath
is not, in fact, a directory.
Or,
oldpath
is a directory, and
newpath
exists but is not a directory.
- ENOTEMPTY or EEXIST
-
newpath
is a nonempty directory, that is, contains entries other than "." and "..".
- EPERM or EACCES
-
The directory containing
oldpath
has the sticky bit
(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
CAP_FOWNER
capability);
or
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
CAP_FOWNER
capability);
or the filesystem containing
pathname
does not support renaming of the type requested.
- EROFS
-
The file is on a read-only filesystem.
- EXDEV
-
oldpath and newpath
are not on the same mounted filesystem.
(Linux permits a filesystem to be mounted at multiple points, but
rename()
does not work across different mount points,
even if the same filesystem is mounted on both.)
The following additional errors can occur for
renameat()
and
renameat2():
- EBADF
-
olddirfd
or
newdirfd
is not a valid file descriptor.
- ENOTDIR
-
oldpath
is relative and
olddirfd
is a file descriptor referring to a file other than a directory;
or similar for
newpath
and
newdirfd
The following additional errors can occur for
renameat2():
- EEXIST
-
flags
contains
RENAME_NOREPLACE
and
newpath
already exists.
- EINVAL
-
An invalid flag was specified in
flags,
or both
RENAME_NOREPLACE
and
RENAME_EXCHANGE
were specified.
- EINVAL
-
The filesystem does not support one of the flags in
flags.
- ENOENT
-
flags
contains
RENAME_EXCHANGE
and
newpath
does not exist.
VERSIONS
renameat()
was added to Linux in kernel 2.6.16;
library support was added to glibc in version 2.4.
renameat2()
was added to Linux in kernel 3.15.
CONFORMING TO
rename():
4.3BSD, C89, C99, POSIX.1-2001, POSIX.1-2008.
renameat():
POSIX.1-2008.
renameat2()
is Linux-specific.
NOTES
Glibc notes
On older kernels where
renameat()
is unavailable, the glibc wrapper function falls back to the use of
rename().
When
oldpath
and
newpath
are relative pathnames,
glibc constructs pathnames based on the symbolic links in
/proc/self/fd
that correspond to the
olddirfd
and
newdirfd
arguments.
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
link(2)
for a similar problem.
SEE ALSO
mv(1),
chmod(2),
link(2),
symlink(2),
unlink(2),
path_resolution(7),
symlink(7)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- renameat()
-
- renameat2()
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- CONFORMING TO
-
- NOTES
-
- Glibc notes
-
- BUGS
-
- SEE ALSO
-
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Time: 02:54:47 GMT, September 18, 2014