ACL semantics -- consistency with existing ACL systems?

[Casey Schaufler]

Andreas Gruenbacher wrote:

> > Unfortunately, I don't have access to an IRIX box so couldn't look at the
> > implementation there.

Blush. We blew off the ACL-editor-in-a-library and did this:
ACL_GET_FILE(3C)                                             
ACL_GET_FILE(3C)

NAME
     acl_get_file, acl_set_file  - get or set the ACL for a pathname

SYNOPSIS
     #include <sys/acl.h>

     struct acl * acl_get_file(const char *path,
     int acl_set_file(const char *path, acl_type_t type, struct acl
*aclp);

DESCRIPTION
     acl_get_file returns a pointer to an allocated struct acl
associated with
     the pathname pointed to by path.  type determines whether the
default ACL
     (type == ACL_TYPE_DEFAULT) or access ACL (type == ACL_TYPE_ACCESS)
is
     returned.  The default ACL is available only for directories.  If
there
     is no default ACL associated with the specified directory, an ACL
     containing zero entries is returned.  If _POSIX_MAC is in effect,
then
     the process must have MAC read access to the object.

     acl_set_file sets the ACL of the specified pathname.  type
indicates
     which ACL, default or access, is to be set.  Only directories can
have a
     default ACL.  If type is not valid, the call fails.  The ACL is
first
     checked for validity by acl_valid(3c).  The effective UID of the
process
     must match the owner of the object or the process must have
appropriate
     privilege to set the access ACL or the default ACL on path.  If
     _POSIX_CAP is in effect, then the appropriate capability must
include
     CAP_FOWNER.  In addition, if _POSIX_MAC is in effect, then the
process
     must have MAC write access to the object.

RETURN VALUES
     acl_get_file a pointer to an allocated struct acl if successful,
NULL
     otherwise.  The storage should be freed with a call to acl_free
with the
     returned pointer as an argument when it is no longer needed.

     acl_set_file returns 0 if successful, -1 otherwise.

ERRORS
     acl_get_file:

     EACCESS         Search permission is denied for a component of the
path
                     prefix or the object exists and the process does
not have
                     appropriate access rights.

     EINVAL          type is not valid

     ENAMETOLONG     The pathname or one of its components is too long.

     ENOENT          The named object does not exist or path points to
an
                     empty string.

     ENOMEM          allocation of the struct acl failed.

                                                                       
Page 1

ACL_GET_FILE(3C)                                             
ACL_GET_FILE(3C)

     ENOSYS          ACL support is not available (not installed).

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

     acl_set_file:

     EACCESS         Search permission is denied for a component of the
path
                     prefix or the object exists and the process does
not have
                     appropriate access rights.

     EINVAL          aclp points to an invalid ACL.  type is not either
                     ACL_TYPE_ACCESS, or ACL_TYPE_DEFAULT.  The ACL is
too
                     large (too many entries).

     ENAMETOLONG     The pathname or one of its components is too long.

     ENOENT          The named object does not exist or path points to
an
                     empty string.

     ENOSPC          The file system is full or some other resource
needed for
                     the ACL storage is not available.

     ENOSYS          ACL support is not available (not installed).

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

     EPERM           The process does not have appropriate privilege to
                     perform the operation to set the ACL.

     EROFS           This function requires modification of a file
system
                     which is currently read-only.

SEE ALSO
     acl(4)


-- 

Casey Schaufler                         voice: (650) 933-1634
casey at sgi.com                           fax:   (650) 933-0170
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