Provided by: libattr1-dev_2.4.46-5ubuntu1_amd64 bug

NAME

       attr_multi,  attr_multif  -  manipulate multiple user attributes on a filesystem object at
       once

C SYNOPSIS

       #include <attr/attributes.h>

       int attr_multi (const char *path, attr_multiop_t *oplist,
                       int count, int flags);

       int attr_multif (int fd, attr_multiop_t *oplist,
                        int count, int flags);

DESCRIPTION

       The attr_multi and attr_multif functions provide a way to operate on  multiple  attributes
       of a filesystem object at once.

       Path  points  to a path name for a filesystem object, and fd refers to the file descriptor
       associated with a file.  The oplist  is  an  array  of  attr_multiop_t  structures.   Each
       element  in  that  array  describes  a  single  attribute  operation  and provides all the
       information required to carry out that operation and to check for success  or  failure  of
       that operation.  Count tells how many elements are in the oplist array.

       The contents of an attr_multiop_t structure include the following members:

          int am_opcode; /* which operation to perform (see below) */
          int am_error; /* [out arg] result of this sub-op (an errno) */
          char *am_attrname; /* attribute name to work with */
          char *am_attrvalue; /* [in/out arg] attribute value (raw bytes) */
          int am_length; /* [in/out arg] length of value */
          int am_flags; /* flags (bit-wise OR of #defines below) */

       The am_opcode field defines how the remaining fields are to be interpreted and can take on
       one of the following values:

          ATTR_OP_GET /* return the indicated attr's value */
          ATTR_OP_SET /* set/create the indicated attr/value pair */
          ATTR_OP_REMOVE /* remove the indicated attr */

       The am_error field will contain the appropriate error result code  if  that  sub-operation
       fails.   The  result codes for a given sub-operation are a subset of the result codes that
       are possible from the corresponding single-attribute  function  call.   For  example,  the
       result  code  possible from an ATTR_OP_GET sub-operation are a subset of those that can be
       returned from an attr_get function call.

       The am_attrname field is a pointer to a NULL terminated string giving the  attribute  name
       that the sub-operation should operate on.

       The  am_attrvalue,  am_length and am_flags fields are used to store the value of the named
       attribute, and some control flags for that sub-operation, respectively.  Their use  varies
       depending on the value of the am_opcode field.

       ATTR_OP_GET
              The am_attrvalue field is a pointer to a empty buffer that will be overwritten with
              the value of the named attribute.  The am_length field is initially the total  size
              of  the  memory buffer that the am_attrvalue field points to.  After the operation,
              the am_length field contains  the  actual  size  of  the  attributeĀ“s  value.   The
              am_flags  field  may  be set to the ATTR_ROOT flag.  If the process has appropriate
              priviledges, the ROOT namespace will be searched for the named attribute, otherwise
              the USER namespace will be searched.

       ATTR_OP_SET
              The am_attrvalue and am_length fields contain the new value for the given attribute
              name and its length.  The ATTR_ROOT flag may be set in the am_flags field.  If  the
              process  has  appropriate  priviledges, the ROOT namespace will be searched for the
              named attribute, otherwise the USER namespace will be  searched.   The  ATTR_CREATE
              and  the  ATTR_REPLACE  flags  may  also  be  set  in  the  am_flags field (but not
              simultaneously).  If the ATTR_CREATE flag is set, the sub-operation  will  set  the
              am_error   field  to  EEXIST  if  the  named  attribute  already  exists.   If  the
              ATTR_REPLACE flag is set, the sub-operation will set the am_error field to  ENOATTR
              if  the  named attribute does not already exist.  If neither of those two flags are
              set and the attribute does not exist, then the attribute will be created  with  the
              given  value.   If  neither  of  those  two flags are set and the attribute already
              exists, then the value will be replaced with the given value.

       ATTR_OP_REMOVE
              The am_attrvalue and am_length fields are not used and are ignored.   The  am_flags
              field  may  be  set  to  the  ATTR_ROOT  flag.   If  the  process  has  appropriate
              priviledges, the ROOT namespace will be searched for the named attribute, otherwise
              the USER namespace will be searched.

       The  flags  argument to the attr_multi call is used to control following of symbolic links
       in the path argument.  The default is to follow symbolic links, flags  should  be  set  to
       ATTR_DONTFOLLOW to not follow symbolic links.

       attr_multi will fail if one or more of the following are true:

       [ENOENT]         The named file does not exist.

       [EPERM]          The  effective  user  ID  does  not  match  the owner of the file and the
                        effective user ID is not super-user.

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

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

       [EINVAL]         A bit other than ATTR_DONTFOLLOW was set in the flag argument.

       [EFAULT]         Path, or oplist  points  outside  the  allocated  address  space  of  the
                        process.

       [ELOOP]          A path name lookup involved too many symbolic links.

       [ENAMETOOLONG]   The  length  of  path  exceeds  {MAXPATHLEN},  or a pathname component is
                        longer than {MAXNAMELEN}.

       attr_multif will fail if:

       [EINVAL]       A bit was set in the flag argument, or fd refers to a socket, not a file.

       [EFAULT]       Oplist points outside the allocated address space of the process.

       [EBADF]        Fd does not refer to a valid descriptor.

DIAGNOSTICS

       On success, zero is returned.  On error, -1 is returned, and errno is  set  appropriately.
       Note  that  the individual operations listed in the oplist array each have their own error
       return fields.  The errno variable only records the result of the attr_multi call  itself,
       not the result of any of the sub-operations.

SEE ALSO

       attr(1), attr_get(3), attr_list(3), attr_remove(3), and attr_set(3).