HP-UX Reference (11i v2 04/09) - 2 System Calls (vol 5)

chmod(2) chmod(2)

Access Control Lists - JFS File Systems Only

The effective permissions granted by optional entries in a ﬁle’s access control list may be changed when

chmod() is executed. In particular, using chmod() to remove read, write and execute permissions

from a ﬁle’s owner, owning group, and all others works as expected, because

chmod() affects the

class entry in the ACL, limiting any access that can be granted to additional users or groups via

optional ACL entries. The effect can be veriﬁed by doing a getacl (1) on the ﬁle after the

chmod(), and

noting that all optional (non-default) ACL entries with nonzero permissions also have the comment

effective:---

To set the permission bits of access control list entries, use

setacl() instead of chmod().

For more information on access control list entries, see acl (5) and aclv (5).

RETURN VALUE

chmod() returns the following values:

0 Successful completion.

-1 Failure.

errno is set to indicate the error.

ERRORS

chmod() fails, the ﬁle mode is unchanged.

errno is set to one of the following values:

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

[EFAULT] path points outside the allocated address space of the process. The reliable

detection of this error is implementation dependent.

[EINVAL] path or ﬁldes descriptor does not refer to an appropriate ﬁle.

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

[ENAMETOOLONG]

A component of path exceeds

NAME_MAX bytes while _POSIX_NO_TRUNC

in effect or path exceeds

PATH_MAX bytes.

[ENOENT] A component of path or the ﬁle named by path does not exist.

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

[EPERM] The effective user ID does not match that of the owner of the ﬁle, and the

effective user ID is not that of a user with appropriate privileges.

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

fchmod() fails, the ﬁle mode is unchanged. errno is set to one of the following values:

[EBADF] ﬁldes is not a valid ﬁle descriptor.

[EPERM] The effective user ID does not match that of the owner of the ﬁle, and the

effective user ID is not that of a user with appropriate privileges.

[EINVAL] path or ﬁldes descriptor does not refer to an appropriate ﬁle.

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

AUTHOR

chmod() was developed by AT&T, the University of California, Berkeley, and HP.

fchmod() was developed by the University of California, Berkeley.