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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | NOTES | SEE ALSO | COLOPHON |
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lookup_dcookie(2) System Calls Manual lookup_dcookie(2)
lookup_dcookie - return a directory entry's path
Standard C library (libc, -lc)
#include <sys/syscall.h> /* Definition of SYS_* constants */
#include <unistd.h>
int syscall(SYS_lookup_dcookie, uint64_t cookie, char *buffer,
size_t len);
Note: glibc provides no wrapper for lookup_dcookie(),
necessitating the use of syscall(2).
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.
On success, lookup_dcookie() returns the length of the path
string copied into the buffer. On error, -1 is returned, and
errno is set to indicate the error.
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.
Linux.
Linux 2.5.43.
The ENAMETOOLONG error was added in Linux 2.5.70.
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.
oprofile(1)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-05-02 lookup_dcookie(2)
Pages that refer to this page: syscalls(2), capabilities(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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