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lookup_dcookie() - Unix, Linux System Call
lookup_dcookie - return a directory entrys path
int lookup_dcookie(u64 cookie, char * buffer, size_t len);
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
lookup_dcookie() to return successfully,
the kernel must still hold a cookie reference to the directory entry.
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.
lookup_dcookie() returns the length of the path string copied into the buffer.
On error, -1 is returned, and
errno is set appropriately.
The buffer was not valid.
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.
The name could not fit in the buffer.
The kernel could not allocate memory for the temporary buffer holding
The process does not have the capability
CAP_SYS_ADMIN required to look up cookie values.
The buffer was not large enough to hold the path of the directory entry.
lookup_dcookie() is Linux-specific.
Since Linux 2.5.43.
The ENAMETOOLONG error return was added in 2.5.70.