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
       cookies 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
       appropriately.

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)