Manpages - lchown.3p
Table of Contents
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.
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 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 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
The length of a pathname exceeds {PATH_MAX}, or pathname resolution 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 ALSO
/chown ( )/, /symlink ( )/
The Base Definitions volume of POSIX.1‐2017, <unistd.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology – Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .
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.kernel.org/doc/man-pages/reporting_bugs.html .