|
|
renaming files
|
|
|
|
RENAME(2) BSD System Calls Manual RENAME(2) NAME
rename -- change the name of a file SYNOPSIS
#include <stdio.h> int rename(const char *old, const char *new); DESCRIPTION
The rename() system call causes the link named old to be renamed as new. If new exists, it is first removed. Both old and new must be of the same type (that is, both must be either directories or non-directories) and must reside on the same file system. The rename() system call guarantees that an instance of new will always exist, even if the system should crash in the middle of the opera- tion. If the final component of old is a symbolic link, the symbolic link is renamed, not the file or directory to which it points. CAVEATS
The system can deadlock if a loop is present in the file system graph. 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. Whether or not hard links to directories are supported is specific to the underlying filesystem implementation. It is recommended that any hard links to directories in an underlying filesystem should be replaced by symbolic links by the system adminis- trator to avoid the possibility of deadlocks. Moving or renaming a file or directory into a directory with inheritable ACLs does not result in ACLs being set on the file or directory. Use acl(3) in conjunction with rename() to set ACLs on the file or directory. 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
The rename() system call will fail and neither of the argument files will be affected if: [EACCES] A component of either path prefix denies search permission. [EACCES] The requested operation requires writing in a directory (e.g., new, new/.., or old/..) whose modes disallow this. [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. [EFAULT] Path points outside the process's allocated address space. [EINVAL] Old is a parent directory of new, or an attempt is made to rename '.' or '..'. [EIO] An I/O error occurs while making or updating a directory entry. [EISDIR] new is a directory, but old is not a directory. [ELOOP] Too many symbolic links are encountered in translating either pathname. This is taken to be indicative of a looping sym- bolic link. [ENAMETOOLONG] A component of a pathname exceeds {NAME_MAX} characters, or an entire path name exceeds {PATH_MAX} characters. [ENOENT] A component of the old path does not exist, or a path prefix of new does not exist. [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. [ENOTDIR] A component of either path prefix is not a directory. [ENOTDIR] old is a directory, but new is not a directory. [ENOTEMPTY] New is a directory and is not empty. [EPERM] The directory containing old is marked sticky, and neither the containing directory nor old are owned by the effective user ID. [EPERM] The new file exists, the directory containing new is marked sticky, and neither the containing directory nor new are owned by the effective user ID. [EROFS] The requested link requires writing in a directory on a read-only file system. [EXDEV] The link named by new and the file named by old are on different logical devices (file systems). Note that this error code will not be returned if the implementation permits cross-device links. CONFORMANCE
The restriction on renaming a directory whose permissions disallow writing is based on the fact that UFS directories contain a ".." entry. If renaming a directory would move it to another parent directory, this entry needs to be changed. This restriction has been generalized to disallow renaming of any write-disabled directory, even when this would not require a change to the ".." entry. For consistency, HFS+ directories emulate this behavior. SEE ALSO
open(2), symlink(7) STANDARDS
The rename() function conforms to IEEE Std 1003.1-1988 (``POSIX.1''). 4.2 Berkeley Distribution September 18, 2008 4.2 Berkeley Distribution
