|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 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¶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.
- 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 path.
- 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.
VERSIONS¶Available since Linux 2.5.43. The ENAMETOOLONG error return was added in 2.5.70.
CONFORMING TO¶lookup_dcookie() is Linux-specific.
NOTES¶lookup_dcookie() is a special-purpose system call, currently used only by the oprofile(1) 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¶This page is part of release 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.