rename(2) - Linux manual page (original) (raw)
rename(2) System Calls Manual rename(2)
NAME top
rename, renameat, renameat2 - change the name or location of a
fileLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#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:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_ATFILE_SOURCE
**renameat2**():
_GNU_SOURCEDESCRIPTION top
**rename**() renames a file, moving it between directories if
required. Any other hard links to the file (as created using
[link(2)](../man2/link.2.html)) are unaffected. Open file descriptors for _oldpath_ are
also unaffected.
Various restrictions determine whether or not the rename operation
succeeds: see ERRORS below.
If _newpath_ already exists, it will be atomically replaced, so that
there is no point at which another process attempting to access
_newpath_ will find it missing. However, there will probably be a
window in which both _oldpath_ and _newpath_ refer to the file being
renamed.
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.
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)](../man2/openat.2.html) 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_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).
**RENAME_NOREPLACE**
Don't overwrite _newpath_ of the rename. Return an error if
_newpath_ already exists.
**RENAME_NOREPLACE** can't be employed together with
**RENAME_EXCHANGE**.
**RENAME_NOREPLACE** requires support from the underlying
filesystem. Support for various filesystems was added as
follows:
• ext4 (Linux 3.15);
• btrfs, tmpfs, and cifs (Linux 3.17);
• xfs (Linux 4.0);
• Support for many other filesystems was added in Linux
4.9, including ext2, minix, reiserfs, jfs, vfat, and
bpf.
**RENAME_WHITEOUT** (since Linux 3.18)
This operation makes sense only for overlay/union
filesystem implementations.
Specifying **RENAME_WHITEOUT** creates a "whiteout" object at
the source of the rename at the same time as performing the
rename. The whole operation is atomic, so that if the
rename succeeds then the whiteout will also have been
created.
A "whiteout" is an object that has special meaning in
union/overlay filesystem constructs. In these constructs,
multiple layers exist and only the top one is ever
modified. A whiteout on an upper layer will effectively
hide a matching file in the lower layer, making it appear
as if the file didn't exist.
When a file that exists on the lower layer is renamed, the
file is first copied up (if not already on the upper layer)
and then renamed on the upper, read-write layer. At the
same time, the source file needs to be "whiteouted" (so
that the version of the source file in the lower layer is
rendered invisible). The whole operation needs to be done
atomically.
When not part of a union/overlay, the whiteout appears as a
character device with a {0,0} device number. (Note that
other union/overlay implementations may employ different
methods for storing whiteout entries; specifically, BSD
union mount employs a separate inode type, **DT_WHT**, which,
while supported by some filesystems available in Linux,
such as CODA and XFS, is ignored by the kernel's whiteout
support code, as of Linux 4.19, at least.)
**RENAME_WHITEOUT** requires the same privileges as creating a
device node (i.e., the **CAP_MKNOD** capability).
**RENAME_WHITEOUT** can't be employed together with
**RENAME_EXCHANGE**.
**RENAME_WHITEOUT** requires support from the underlying
filesystem. Among the filesystems that support it are
tmpfs (since Linux 3.18), ext4 (since Linux 3.18), XFS
(since Linux 4.1), f2fs (since Linux 4.2), btrfs (since
Linux 4.7), and ubifs (since Linux 4.9).RETURN VALUE top
On success, zero is returned. On error, -1 is returned, and _[errno](../man3/errno.3.html)_
is set to indicate the error.ERRORS top
**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)](../man7/path%5Fresolution.7.html).)
**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 a 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
_oldpath_ 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** _oldpath_ (_newpath_) is relative but _olddirfd_ (_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_.
**EINVAL** Both **RENAME_NOREPLACE** and **RENAME_EXCHANGE** were specified in
_flags_.
**EINVAL** Both **RENAME_WHITEOUT** and **RENAME_EXCHANGE** were specified in
_flags_.
**EINVAL** The filesystem does not support one of the flags in _flags_.
**ENOENT** _flags_ contains **RENAME_EXCHANGE** and _newpath_ does not exist.
**EPERM RENAME_WHITEOUT** was specified in _flags_, but the caller does
not have the **CAP_MKNOD** capability.STANDARDS top
**rename**()
C11, POSIX.1-2008.
**renameat**()
POSIX.1-2008.
**renameat2**()
Linux.HISTORY top
**rename**()
4.3BSD, C89, POSIX.1-2001.
**renameat**()
Linux 2.6.16, glibc 2.4.
**renameat2**()
Linux 3.15, glibc 2.28.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 top
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)](../man2/link.2.html) for a
similar problem.SEE ALSO top
[mv(1)](../man1/mv.1.html), [rename(1)](../man1/rename.1.html), [chmod(2)](../man2/chmod.2.html), [link(2)](../man2/link.2.html), [symlink(2)](../man2/symlink.2.html), [unlink(2)](../man2/unlink.2.html),
[path_resolution(7)](../man7/path%5Fresolution.7.html), [symlink(7)](../man7/symlink.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 rename(2)
Pages that refer to this page:exch(1), mv(1), fcntl(2), io_uring_enter2(2), io_uring_enter(2), link(2), open(2), rmdir(2), symlink(2), syscalls(2), unlink(2), io_uring_prep_rename(3), io_uring_prep_renameat(3), remove(3), cpuset(7), inotify(7), signal-safety(7), symlink(7), lsof(8), mount(8)