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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_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_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.

              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  provide  that  support are shmem (since Linux 3.18), ext4 (since
              Linux 3.18), and XFS (since Linux 4.1).

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.

       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.

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)

COLOPHON

       This  page  is  part of release 4.04 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 http://www.kernel.org/doc/man-pages/.