LCHOWN(3P) POSIX Programmer's Manual LCHOWN(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAMElchown — 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 implemen‐
tation.
ELOOP A loop exists in symbolic links encountered during resolution of
the path argument.
ENAMETOOLONG
The length of a component of a pathname 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 names an existing file that is
neither a directory nor a symbolic link to a directory, or the
path argument contains at least one non-<slash> character and
ends with one or more trailing <slash> characters and the last
pathname component names an existing file that is neither a
directory nor a symbolic link to a directory.
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 sys‐
tem.
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
The length of a pathname exceeds {PATH_MAX}, or pathname resolu‐
tion of a symbolic link produced an intermediate result with a
length that 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 ALSOchown(), symlink()
The Base Definitions volume of POSIX.1‐2008, <unistd.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 LCHOWN(3P)
