NAME
lchown - change the owner and group of a symbolic link
SYNOPSIS
#include <unistd.h>
int lchown(const char *path, uid_t owner, gid_t group);
DESCRIPTION
The lchown() function shall be equivalent to chown(), except in the
case where the named file is a symbolic link. In this case, lchown()
shall change the ownership of the symbolic link file itself, while
chown() changes the ownership of the file or directory to which the
symbolic link refers.
RETURN VALUE
Upon successful completion, lchown() shall return 0. Otherwise, it
shall return -1 and set errno to indicate an error.
ERRORS
The lchown() function shall fail if:
EACCES Search permission is denied on a component of the path prefix of
path.
EINVAL The owner or group ID is not a value supported by the
implementation.
ELOOP A loop exists in symbolic links encountered during resolution of
the path argument.
ENAMETOOLONG
The length of a pathname exceeds {PATH_MAX} or a pathname
component is longer than {NAME_MAX}.
ENOENT A component of path does not name an existing file or path is an
empty string.
ENOTDIR
A component of the path prefix of path is not a directory.
EOPNOTSUPP
The path argument names a symbolic link and the implementation
does not support setting the owner or group of a symbolic link.
EPERM The effective user ID does not match the owner of the file and
the process does not have appropriate privileges.
EROFS The file resides on a read-only file system.
The lchown() function may fail if:
EIO An I/O error occurred while reading or writing to the file
system.
EINTR A signal was caught during execution of the function.
ELOOP More than {SYMLOOP_MAX} symbolic links were encountered during
resolution of the path argument.
ENAMETOOLONG
Pathname resolution of a symbolic link produced an intermediate
result whose length exceeds {PATH_MAX}.
The following sections are informative.
EXAMPLES
Changing the Current Owner of a File
The following example shows how to change the ownership of the symbolic
link named /modules/pass1 to the user ID associated with "jones" and
the group ID associated with "cnd".
The numeric value for the user ID is obtained by using the getpwnam()
function. The numeric value for the group ID is obtained by using the
getgrnam() function.
#include <sys/types.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
struct passwd *pwd;
struct group *grp;
char *path = "/modules/pass1";
...
pwd = getpwnam("jones");
grp = getgrnam("cnd");
lchown(path, pwd->pw_uid, grp->gr_gid);
APPLICATION USAGE
On implementations which support symbolic links as directory entries
rather than files, lchown() may fail.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
chown() , symlink() , the Base Definitions volume of
IEEE Std 1003.1-2001, <unistd.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .