lookup_dcookie
Section: System Calls (2)
Updated: 2022-12-04
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NAME
lookup_dcookie - return a directory entry's path
LIBRARY
Standard C library
(libc, -lc)
SYNOPSIS
#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).
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 to indicate the error.
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
ENAMETOOLONG
error return was added in Linux 2.5.70.
STANDARDS
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.
SEE ALSO
oprofile(1)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- STANDARDS
-
- NOTES
-
- SEE ALSO
-
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Time: 15:06:19 GMT, April 18, 2024