linux-stable/include/uapi/linux/random.h
Gustavo A. R. Silva 94dfc73e7c treewide: uapi: Replace zero-length arrays with flexible-array members
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:

../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
		strcpy(de3->name, ".");
		^

Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2022-06-28 21:26:05 +02:00

58 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* include/linux/random.h
*
* Include file for the random number generator.
*/
#ifndef _UAPI_LINUX_RANDOM_H
#define _UAPI_LINUX_RANDOM_H
#include <linux/types.h>
#include <linux/ioctl.h>
#include <linux/irqnr.h>
/* ioctl()'s for the random number generator */
/* Get the entropy count. */
#define RNDGETENTCNT _IOR( 'R', 0x00, int )
/* Add to (or subtract from) the entropy count. (Superuser only.) */
#define RNDADDTOENTCNT _IOW( 'R', 0x01, int )
/* Get the contents of the entropy pool. (Superuser only.) */
#define RNDGETPOOL _IOR( 'R', 0x02, int [2] )
/*
* Write bytes into the entropy pool and add to the entropy count.
* (Superuser only.)
*/
#define RNDADDENTROPY _IOW( 'R', 0x03, int [2] )
/* Clear entropy count to 0. (Superuser only.) */
#define RNDZAPENTCNT _IO( 'R', 0x04 )
/* Clear the entropy pool and associated counters. (Superuser only.) */
#define RNDCLEARPOOL _IO( 'R', 0x06 )
/* Reseed CRNG. (Superuser only.) */
#define RNDRESEEDCRNG _IO( 'R', 0x07 )
struct rand_pool_info {
int entropy_count;
int buf_size;
__u32 buf[];
};
/*
* Flags for getrandom(2)
*
* GRND_NONBLOCK Don't block and return EAGAIN instead
* GRND_RANDOM No effect
* GRND_INSECURE Return non-cryptographic random bytes
*/
#define GRND_NONBLOCK 0x0001
#define GRND_RANDOM 0x0002
#define GRND_INSECURE 0x0004
#endif /* _UAPI_LINUX_RANDOM_H */