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      1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
      2 /*
      3  * include/linux/random.h
      4  *
      5  * Include file for the random number generator.
      6  */
      7 
      8 #ifndef _UAPI_LINUX_RANDOM_H
      9 #define _UAPI_LINUX_RANDOM_H
     10 
     11 #include <linux/types.h>
     12 #include <linux/ioctl.h>
     13 #include <linux/irqnr.h>
     14 
     15 /* ioctl()'s for the random number generator */
     16 
     17 /* Get the entropy count. */
     18 #define RNDGETENTCNT	_IOR( 'R', 0x00, int )
     19 
     20 /* Add to (or subtract from) the entropy count.  (Superuser only.) */
     21 #define RNDADDTOENTCNT	_IOW( 'R', 0x01, int )
     22 
     23 /* Get the contents of the entropy pool.  (Superuser only.) */
     24 #define RNDGETPOOL	_IOR( 'R', 0x02, int [2] )
     25 
     26 /*
     27  * Write bytes into the entropy pool and add to the entropy count.
     28  * (Superuser only.)
     29  */
     30 #define RNDADDENTROPY	_IOW( 'R', 0x03, int [2] )
     31 
     32 /* Clear entropy count to 0.  (Superuser only.) */
     33 #define RNDZAPENTCNT	_IO( 'R', 0x04 )
     34 
     35 /* Clear the entropy pool and associated counters.  (Superuser only.) */
     36 #define RNDCLEARPOOL	_IO( 'R', 0x06 )
     37 
     38 struct rand_pool_info {
     39 	int	entropy_count;
     40 	int	buf_size;
     41 	__u32	buf[0];
     42 };
     43 
     44 /*
     45  * Flags for getrandom(2)
     46  *
     47  * GRND_NONBLOCK	Don't block and return EAGAIN instead
     48  * GRND_RANDOM		Use the /dev/random pool instead of /dev/urandom
     49  */
     50 #define GRND_NONBLOCK	0x0001
     51 #define GRND_RANDOM	0x0002
     52 
     53 #endif /* _UAPI_LINUX_RANDOM_H */
     54