renameat2(2) — Linux manual page


RENAME(2)                 Linux Programmer's Manual                RENAME(2)

NAME         top

       rename, renameat, renameat2 - change the name or location of a file

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)):

           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:

DESCRIPTION         top

       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.

       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

       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.

       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() 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:

              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).

              Don't overwrite newpath of the rename.  Return an error if
              newpath already exists.

              RENAME_NOREPLACE can't be employed together with

              RENAME_NOREPLACE requires support from the underlying
              filesystem.  Support for various filesystems was added as

              *  ext4 (Linux 3.15);

              *  btrfs, shmem, 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

              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_WHITEOUT requires support from the underlying
              filesystem.  Among the filesystems that provide that support
              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 is
       set appropriately.

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

       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

       EDQUOT The user's quota of disk blocks on the filesystem has been

       EFAULT oldpath or newpath points outside your accessible address

       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

       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.

              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.

              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.

              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

       EBADF  olddirfd or newdirfd is not a valid file descriptor.

              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

       EINVAL Both RENAME_WHITEOUT and RENAME_EXCHANGE were specified in

       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.

VERSIONS         top

       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; library support was
       added in glibc 2.28.

CONFORMING TO         top

       rename(): 4.3BSD, C89, C99, POSIX.1-2001, POSIX.1-2008.

       renameat(): POSIX.1-2008.

       renameat2() is Linux-specific.

NOTES         top

   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) for a similar problem.

SEE ALSO         top

       mv(1), rename(1), chmod(2), link(2), symlink(2), unlink(2),
       path_resolution(7), symlink(7)

COLOPHON         top

       This page is part of release 5.09 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                            2020-06-09                        RENAME(2)

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