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

NAME         top

       lookup_dcookie - return a directory entry's path

SYNOPSIS         top

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

DESCRIPTION         top

       Look up the full path of the directory entry specified by the value cookie.
       The cookie is an opaque identifier uniquely identifying a particular 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.

RETURN VALUE         top

       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         top

       EFAULT The buffer was not valid.

       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.

       ENAMETOOLONG
              The name could not fit in the buffer.

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

       EPERM  The process does not have the capability CAP_SYS_ADMIN required to look
              up cookie values.

       ERANGE The buffer was not large enough to hold the path of the directory
              entry.

VERSIONS         top

       Available since Linux 2.5.43.  The ENAMETOOLONG error return was added in
       2.5.70.

CONFORMING TO         top

       lookup_dcookie() is Linux-specific.

NOTES         top

       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.

COLOPHON         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

Linux                                 2004-06-17                    LOOKUP_DCOOKIE(2)

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