lookup_dcookie

LOOKUP_DCOOKIE(2)          Linux Programmer's Manual         LOOKUP_DCOOKIE(2)



NAME
       lookup_dcookie - return a directory entry's path

SYNOPSIS
       int lookup_dcookie(u64 cookie, char * buffer, size_t len);

DESCRIPTION
       Look  up  the  full  path of the directory entry specified by the value
       cookie The cookie is an opaque identifier uniquely identifying  a  par-
       ticular  directory  entry.  The buffer given is filled in with the full
       path of the directory entry.

       For lookup_dcookie to return successfully, the kernel must still hold a
       cookie reference to the directory entry.


NOTES
       lookup_dcookie is a special-purpose system call, currently used only by
       the oprofile profiler.  It relies on a kernel driver to register  cook-
       ies for directory entries.

       The  path  returned  may  be suffixed by the string " (deleted)" if the
       directory entry has been removed.


RETURN VALUE
       On success, lookup_dcookie returns the length of the path string copied
       into  the buffer.  On error, -1 is returned, and errno is set appropri-
       ately.

ERRORS
       EPERM The process does not have the capability to look up  cookie  val-
       ues.

       EINVAL The  kernel has no registered cookie/directory entry mappings at
              the time of lookup, or the cookie does  not  refer  to  a  valid
              directory entry.

       ENOMEM The  kernel  could  not allocate memory for the temporary buffer
              holding the path.

       ERANGE The buffer was not large enough to hold the path of  the  direc-
              tory entry.

       ENAMETOOLONG
              The name could not fit in the buffer.

       EFAULT The buffer was not valid.


CONFORMING TO
       lookup_dcookie is Linux-specific.

AVAILABILITY
       Since Linux 2.5.43.  The ENAMETOOLONG error return was added in 2.5.70.




Linux 2.5.43                      2003-02-09                 LOOKUP_DCOOKIE(2)