RENAME(2) System Calls RENAME(2)


NAME


rename, renameat - change the name of a file

SYNOPSIS


#include <stdio.h>

int rename(const char *old, const char *new);


#include <unistd.h>

int renameat(int fromfd, const char *old, int tofd,
const char *new);


XPG3
#include <unistd.h>

int rename(const char *old, const char *new);


DESCRIPTION


The rename() function changes the name of a file. The old argument
points to the pathname of the file to be renamed. The new argument points
to the new path name of the file.


The renameat() function renames an entry in a directory, possibly moving
the entry into a different directory. See fsattr(5). If the old argument
is an absolute path, the fromfd is ignored. Otherwise it is resolved
relative to the fromfd argument rather than the current working
directory. Similarly, if the new argument is not absolute, it is
resolved relative to the tofd argument. If either fromfd or tofd have
the value AT_FDCWD, defined in <fcntl.h>, and their respective paths are
relative, the path is resolved relative to the current working directory.


Current implementation restrictions will cause the renameat() function to
return an error if an attempt is made to rename an extended attribute
file to a regular (non-attribute) file, or to rename a regular file to an
extended attribute file.


If old and new both refer to the same existing file, the rename() and
renameat() functions return successfully and performs no other action.


If old points to the pathname of a file that is not a directory, new must
not point to the pathname of a directory. If the link named by new
exists, it will be removed and old will be renamed to new. In this case,
a link named new must remain visible to other processes throughout the
renaming operation and will refer to either the file referred to by new
or the file referred to as old before the operation began.


If old points to the pathname of a directory, new must not point to the
pathname of a file that is not a directory. If the directory named by new
exists, it will be removed and old will be renamed to new. In this case,
a link named new will exist throughout the renaming operation and will
refer to either the file referred to by new or the file referred to as
old before the operation began. Thus, if new names an existing
directory, it must be an empty directory.


The new pathname must not contain a path prefix that names old. Write
access permission is required for both the directory containing old and
the directory containing new. If old points to the pathname of a
directory, write access permission is required for the directory named
by old, and, if it exists, the directory named by new.


If the directory containing old has the sticky bit set, at least one of
the following conditions listed below must be true:

o the user must own old

o the user must own the directory containing old

o old must be writable by the user

o the user must be a privileged user


If new exists, and the directory containing new is writable and has the
sticky bit set, at least one of the following conditions must be true:

o the user must own new

o the user must own the directory containing new

o new must be writable by the user

o the user must be a privileged user


If the link named by new exists, the file's link count becomes zero when
it is removed, and no process has the file open, then the space occupied
by the file will be freed and the file will no longer be accessible. If
one or more processes have the file open when the last link is removed,
the link will be removed before rename() or renameat() returns, but the
removal of the file contents will be postponed until all references to
the file have been closed.


Upon successful completion, the rename() and renameat() functions will
mark for update the st_ctime and st_mtime fields of the parent directory
of each file.

RETURN VALUES


Upon successful completion, 0 is returned. Otherwise, -1 is returned and
errno is set to indicate an error.

ERRORS


The rename() function will fail if:

EACCES
A component of either path prefix denies search
permission; one of the directories containing old and new
denies write permissions; or write permission is denied
by a directory pointed to by old or new.


EBUSY
The new argument is a directory and the mount point for a
mounted file system.


EDQUOT
The directory where the new name entry is being placed
cannot be extended because the user's quota of disk
blocks on that file system has been exhausted.


EEXIST
The link named by new is a directory containing entries
other than `.' (the directory itself) and `..' (the
parent directory).


EFAULT
Either old or new references an invalid address.


EILSEQ
The path argument includes non-UTF8 characters and the
file system accepts only file names where all characters
are part of the UTF-8 character codeset.


EINVAL
The new argument directory pathname contains a path
prefix that names the old directory, or an attempt was
made to rename a regular file to an extended attribute or
from an extended attribute to a regular file.


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


EISDIR
The new argument points to a directory but old points to
a file that is not a directory.


ELOOP
Too many symbolic links were encountered in translating
the pathname.


ENAMETOOLONG
The length of old or new exceeds PATH_MAX, or a pathname
component is longer than NAME_MAX while _POSIX_NO_TRUNC
is in effect.


EMLINK
The file named by old is a directory, and the link count
of the parent directory of new would exceed LINK_MAX.


ENOENT
The link named by old does not name an existing file, a
component of the path prefix of new does not exist, or
either old or new points to an empty string.


ENOSPC
The directory that would contain new cannot be extended.


ENOTDIR
A component of either path prefix is not a directory, or
old names a directory and new names a file that is not a
directory, or tofd and dirfd in renameat() do not
reference a directory.


EROFS
The requested operation requires writing in a directory
on a read-only file system.


EXDEV
The links named by old and new are on different file
systems.


The renameat() functions will fail if:

ENOTSUP
An attempt was made to rename a regular file as an attribute
file or to rename an attribute file as a regular file.


ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+---------------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+---------------------------------+
|Interface Stability | Committed |
+--------------------+---------------------------------+
|MT-Level | Async-Signal-Safe |
+--------------------+---------------------------------+
|Standard | For rename(), see standards(5). |
+--------------------+---------------------------------+

SEE ALSO


chmod(2), link(2), unlink(2), attributes(5), fsattr(5), standards(5)

NOTES


The system can deadlock if there is a loop in the file system graph. Such
a loop can occur if there is an entry in directory a, a/name1, that is a
hard link to directory b, and an entry in directory b, b/name2, that is a
hard link to directory a. When such a loop exists and two separate
processes attempt to rename a/name1 to b/name2 and b/name2 to a/name1,
the system may deadlock attempting to lock both directories for
modification. Use symbolic links instead of hard links for directories.


October 4, 2007 RENAME(2)