NAME

       chown, fchown, lchown, fchownat — change owner and group of a file

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <unistd.h>

       int
       chown(const char *path, uid_t owner, gid_t group);

       int
       fchown(int fd, uid_t owner, gid_t group);

       int
       lchown(const char *path, uid_t owner, gid_t group);

       int
       fchownat(int fd, const char *path, uid_t owner, gid_t group, int flag);

DESCRIPTION

       The  owner  ID  and group ID of the file named by path or referenced by fd is changed as specified by the
       arguments owner and group.  The owner of a file may change the group to a group of which he or she  is  a
       member, but the change owner capability is restricted to the super-user.

       The chown() system call clears the set-user-id and set-group-id bits on the file to prevent accidental or
       mischievous  creation  of  set-user-id  and set-group-id programs if not executed by the super-user.  The
       chown() system call follows symbolic links to operate on the target of the  link  rather  than  the  link
       itself.

       The fchown() system call is particularly useful when used in conjunction with the file locking primitives
       (see flock(2)).

       The lchown() system call is similar to chown() but does not follow symbolic links.

       The  fchownat()  system  call  is  equivalent  to  the chown() and lchown() except in the case where path
       specifies a relative path.  In this case the file to be changed is determined relative to  the  directory
       associated with the file descriptor fd instead of the current working directory.

       Values  for  flag  are constructed by a bitwise-inclusive OR of flags from the following list, defined in
       <fcntl.h>:

       AT_SYMLINK_NOFOLLOW
               If path names a symbolic link, ownership of the symbolic link is changed.

       If fchownat() is passed the special value AT_FDCWD in the fd parameter, the current working directory  is
       used and the behavior is identical to a call to chown() or lchown() respectively, depending on whether or
       not the AT_SYMLINK_NOFOLLOW bit is set in the flag argument.

       One of the owner or group id's may be left unchanged by specifying it as -1.

RETURN VALUES

       Upon  successful  completion,  the value 0 is returned; otherwise the value -1 is returned and the global
       variable errno is set to indicate the error.

ERRORS

       The chown() and lchown() will fail and the file will be unchanged if:

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

       [ENAMETOOLONG]     A component of a pathname exceeded 255 characters, or an  entire  path  name  exceeded
                          1023 characters.

       [ENOENT]           The named file does not exist.

       [EACCES]           Search permission is denied for a component of the path prefix.

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

       [EPERM]            The  operation would change the ownership, but the effective user ID is not the super-
                          user.

       [EPERM]            The named file has its immutable or append-only flag set, see  the  chflags(2)  manual
                          page for more information.

       [EROFS]            The named file resides on a read-only file system.

       [EFAULT]           The path argument points outside the process's allocated address space.

       [EIO]              An I/O error occurred while reading from or writing to the file system.

       [EINTEGRITY]       Corrupted data was detected while reading from the file system.

       The fchown() system call will fail if:

       [EBADF]            The fd argument does not refer to a valid descriptor.

       [EINVAL]           The fd argument refers to a socket, not a file.

       [EPERM]            The effective user ID is not the super-user.

       [EROFS]            The named file resides on a read-only file system.

       [EIO]              An I/O error occurred while reading from or writing to the file system.

       [EINTEGRITY]       Corrupted data was detected while reading from the file system.

       In addition to the errors specified for chown() and lchown(), the fchownat() system call may fail if:

       [EBADF]            The  path  argument  does  not specify an absolute path and the fd argument is neither
                          AT_FDCWD nor a valid file descriptor open for searching.

       [EINVAL]           The value of the flag argument is not valid.

       [ENOTDIR]          The path argument is not an absolute path and  fd  is  neither  AT_FDCWD  nor  a  file
                          descriptor associated with a directory.

SEE ALSO

       chgrp(1), chflags(2), chmod(2), flock(2), chown(8)

STANDARDS

       The chown() system call is expected to conform to ISO/IEC 9945-1:1990 (“POSIX.1”).  The fchownat() system
       call follows The Open Group Extended API Set 2 specification.

HISTORY

       The chown() function appeared in Version 1 AT&T UNIX.  The fchown() system call appeared in 4.2BSD.

       The  chown()  system  call  was changed to follow symbolic links in 4.4BSD.  The lchown() system call was
       added in FreeBSD 3.0 to compensate for the loss of functionality.

       The fchownat() system call appeared in FreeBSD 8.0.

Debian                                           March 30, 2020                                         CHOWN(2)