Originální popis anglicky:
lchown - change the owner and group of a symbolic link
Návod, kniha: POSIX Programmer's Manual
#include <unistd.h>
int lchown(const char *
path, uid_t
owner , gid_t group);
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.
Upon successful completion,
lchown() shall return 0. Otherwise, it shall
return -1 and set
errno to indicate an error.
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.
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);
On implementations which support symbolic links as directory entries rather than
files,
lchown() may fail.
None.
None.
chown() ,
symlink() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<unistd.h>
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
.
