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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | VERSIONS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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KEYCTL_DESCRIBE(2const) KEYCTL_DESCRIBE(2const)
KEYCTL_DESCRIBE - describe a key
Standard C library (libc, -lc)
#include <linux/keyctl.h> /* Definition of KEY* constants */
#include <sys/syscall.h> /* Definition of SYS_* constants */
#include <unistd.h>
long syscall(size_t size;
SYS_keyctl, KEYCTL_DESCRIBE, key_serial_t key,
char desc[_Nullable size], size_t size);
Obtain a string describing the attributes of a specified key.
The ID of the key to be described is specified in key. The
descriptive string is returned in the buffer pointed to by desc;
size specifies the size of that buffer in bytes.
The key must grant the caller view permission.
The returned string is null-terminated and contains the following
information about the key:
type;uid;gid;perm;description
In the above, type and description are strings, uid and gid are
decimal strings, and perm is a hexadecimal permissions mask. The
descriptive string is written with the following format:
%s;%d;%d;%08x;%s
Note: the intention is that the descriptive string should be
extensible in future kernel versions. In particular, the
description field will not contain semicolons; it should be parsed
by working backwards from the end of the string to find the last
semicolon. This allows future semicolon-delimited fields to be
inserted in the descriptive string in the future.
Writing to the buffer is attempted only when desc is non-NULL and
the specified buffer size is large enough to accept the
descriptive string (including the terminating null byte). In
order to determine whether the buffer size was too small, check to
see if the return value of the operation is greater than size.
On success, the size of the description (including the terminating
null byte), irrespective of the provided buffer size.
On error, -1 is returned, and errno is set to indicate the error.
A wrapper is provided in the libkeyutils library:
keyctl_describe(3).
Linux.
Linux 2.6.10.
keyctl(2), keyctl_describe(3), keyctl_describe_alloc(3)
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-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. 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 6.15 2025-06-28 KEYCTL_DESCRIBE(2const)
Pages that refer to this page: keyctl(2), KEYCTL_SETPERM(2const)
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HTML rendering created 2025-09-06 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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