rename



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


NAME

     rename, renameat - change the name of a file


SYNOPSIS

     #include <stdio.h>

     int
     rename(const char *from, const char *to);

     #include <fcntl.h>
     #include <stdio.h>

     int
     renameat(int fromfd, const char *from, int tofd, const char *to);


DESCRIPTION

     The rename() function causes the link named from to be renamed as to.  If
     to exists, it is first removed.  Both from and to must be of the same
     type (that is, both directories or both non-directories), and must reside
     on the same file system.

     rename() guarantees that if to already exists, an instance of to will
     always exist, even if the system should crash in the middle of the
     operation.

     If the final component of from is a symbolic link, the symbolic link is
     renamed, not the file or directory to which it points.

     The renameat() function is equivalent to rename() except that where from
     or to specifies a relative path, the directory entry names used are
     resolved relative to the directories associated with file descriptors
     fromfd or tofd (respectively) instead of the current working directory.

     If renameat() is passed the special value AT_FDCWD (defined in <fcntl.h>)
     in the fromfd or tofd parameter, the current working directory is used
     for resolving the respective from or to argument.


RETURN VALUES

     A 0 value is returned if the operation succeeds, otherwise rename()
     returns -1 and the global variable errno indicates the reason for the
     failure.


ERRORS

     rename() and renameat() will fail and neither of the argument files will
     be affected if:

     [ENAMETOOLONG]     A component of a pathname exceeded {NAME_MAX}
                        characters, or an entire path name exceeded {PATH_MAX}
                        characters.

     [ENOENT]           A component of the from path does not exist, or a path
                        prefix of to does not exist.

     [EACCES]           A component of either path prefix denies search
                        permission.

     [EACCES]           The requested change requires writing in a directory
                        that denies write permission.

     [EACCES]           The from argument is a directory and denies write
                        permission.

     [EPERM]            The directory containing from is marked sticky, and
                        neither the containing directory nor from are owned by
                        the effective user ID.

     [EPERM]            The to file exists, the directory containing to is
                        marked sticky, and neither the containing directory
                        nor to are owned by the effective user ID.

     [ELOOP]            Too many symbolic links were encountered in
                        translating either pathname.

     [EMLINK]           The link count on the source file or destination
                        directory is at the maximum.  A rename cannot be
                        completed under these conditions.

     [ENOTDIR]          A component of either path prefix is not a directory.

     [ENOTDIR]          from is a directory, but to is not a directory.

     [EISDIR]           to is a directory, but from is not a directory.

     [EXDEV]            The link named by to and the file named by from are on
                        different logical devices (file systems).  Note that
                        this error code will not be returned if the
                        implementation permits cross-device links.

     [ENOSPC]           The directory in which the entry for the new name is
                        being placed cannot be extended because there is no
                        space left on the file system containing the
                        directory.

     [EDQUOT]           The directory in which the entry for the new name is
                        being placed cannot be extended because the user's
                        quota of disk blocks on the file system containing the
                        directory has been exhausted.

     [EIO]              An I/O error occurred while making or updating a
                        directory entry.

     [EROFS]            The requested link requires writing in a directory on
                        a read-only file system.

     [EFAULT]           from or to points outside the process's allocated
                        address space.

     [EINVAL]           from is a parent directory of to, or an attempt is
                        made to rename `.' or `..'.

     [ENOTEMPTY]        to is a directory and is not empty.

     Additionally, renameat() will fail if:

     [EBADF]            The from or to argument specifies a relative path and
                        the fromfd or tofd argument, respectively, is neither
                        AT_FDCWD nor a valid file descriptor.

     [ENOTDIR]          The from or to argument specifies a relative path and
                        the fromfd or tofd argument, respectively, is a valid
                        file descriptor but it does not reference a directory.

     [EACCES]           The from or to argument specifies a relative path but
                        search permission is denied for the directory which
                        the fromfd or tofd file descriptor, respectively,
                        references.


SEE ALSO

     mv(1), open(2), symlink(7)


STANDARDS

     The rename() and renameat() functions conform to IEEE Std 1003.1-2008
     (``POSIX.1'').


HISTORY

     The renameat() function appeared in OpenBSD 5.0.


CAVEATS

     The system can deadlock if a loop in the file system graph is present.
     This loop takes the form of an entry in directory `a', say `a/foo', being
     a hard link to directory `b', and an entry in directory `b', say `b/bar',
     being a hard link to directory `a'.  When such a loop exists and two
     separate processes attempt to perform `rename a/foo b/bar' and `rename
     b/bar a/foo', respectively, the system may deadlock attempting to lock
     both directories for modification.  Hard links to directories should be
     replaced by symbolic links by the system administrator.

OpenBSD 5.4                       May 8, 2013                      OpenBSD 5.4

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