Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
#include <unistd.h>
#include <sys/syscall.h>
#include <linux/bug.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <linux/bug.h>
#ifdef SYS_getrandom
static inline int getrandom(void *buf, size_t buflen, unsigned int flags)
#ifdef SYS_getrandom
static inline int getrandom(void *buf, size_t buflen, unsigned int flags)
get_random_type(int);
get_random_type(long);
get_random_type(int);
get_random_type(long);
+get_random_type(u8);
+get_random_type(u16);
get_random_type(u32);
get_random_type(u64);
get_random_type(u32);
get_random_type(u64);
+static inline u32 get_random_u32_below(u32 ceil)
+{
+ if (ceil <= 1)
+ return 0;
+ for (;;) {
+ if (ceil <= 1U << 8) {
+ u32 mult = ceil * get_random_u8();
+ if (likely(is_power_of_2(ceil) || (u8)mult >= (1U << 8) % ceil))
+ return mult >> 8;
+ } else if (ceil <= 1U << 16) {
+ u32 mult = ceil * get_random_u16();
+ if (likely(is_power_of_2(ceil) || (u16)mult >= (1U << 16) % ceil))
+ return mult >> 16;
+ } else {
+ u64 mult = (u64)ceil * get_random_u32();
+ if (likely(is_power_of_2(ceil) || (u32)mult >= -ceil % ceil))
+ return mult >> 32;
+ }
+ }
+}
+
#endif /* _LINUX_RANDOM_H */
#endif /* _LINUX_RANDOM_H */