NAME
lookup_dcookie - return a directory entry's path
SYNOPSIS
I 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 particular
directory entry.
The buffer given is filled in with the full path of the directory entry.
For
R lookup_dcookie ()
to return successfully,
the kernel must still hold a cookie reference to the directory entry.
RETURN VALUE
On success,
R lookup_dcookie ()
returns the length of the path string copied into the buffer.
On error, -1 is returned, and
errno
is set appropriately.
ERRORS
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
Available since Linux 2.5.43.
The
R ENAMETOOLONG
error return was added in 2.5.70.
CONFORMING TO
R lookup_dcookie ()
is Linux specific.
NOTES
R 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.
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