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Cygwin: random: make random(3) functions thread-safe 

Add locking to the random(3) family of functions to gain
thread-safety per POSIX. Use NetBSD version of the file as
role-model.

Reported-by: Bruno Haible <bruno@clisp.org>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2023-11-13 19:41:08 +01:00
parent 3d94e07c49
commit 06e463223b
1 changed files with 41 additions and 6 deletions
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47
winsup/cygwin/random.cc
View File

@ -29,6 +29,14 @@
#define __INSIDE_CYGWIN__
#include "winsup.h"
SRWLOCK NO_COPY rndlock = SRWLOCK_INIT;
# define __random_lock() { if (__isthreaded) \
AcquireSRWLockExclusive (&rndlock); }
# define __random_unlock() { if (__isthreaded) \
ReleaseSRWLockExclusive (&rndlock); }
extern "C" {
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)random.c 8.2 (Berkeley) 5/19/95";
@ -248,6 +256,8 @@ static inline uint32_t good_rand (int32_t x)
#endif /* !USE_WEAK_SEEDING */
}
static long __random_unlocked();
/*
* srandom:
*
@ -260,8 +270,8 @@ static inline uint32_t good_rand (int32_t x)
* introduced by the L.C.R.N.G. Note that the initialization of randtbl[]
* for default usage relies on values produced by this routine.
*/
void
srandom(unsigned x)
static void
__srandom_unlocked(unsigned x)
{
int i, lim;
@ -276,7 +286,15 @@ srandom(unsigned x)
lim = 10 * rand_deg;
}
for (i = 0; i < lim; i++)
(void)random();
(void)__random_unlocked();
}
void
srandom(unsigned x)
{
__random_lock();
__srandom_unlocked(x);
__random_unlock();
}
/*
@ -351,6 +369,7 @@ initstate(unsigned seed, /* seed for R.N.G. */
char *ostate = (char *)(&state[-1]);
uint32_t *int_arg_state = (uint32_t *)arg_state;
__random_lock();
if (rand_type == TYPE_0)
state[-1] = rand_type;
else
@ -359,6 +378,7 @@ initstate(unsigned seed, /* seed for R.N.G. */
(void)fprintf(stderr,
"random: not enough state (%lu bytes); ignored.\n",
(unsigned long) n);
__random_unlock();
return(0);
}
if (n < BREAK_1) {
@ -384,11 +404,12 @@ initstate(unsigned seed, /* seed for R.N.G. */
}
state = int_arg_state + 1; /* first location */
end_ptr = &state[rand_deg]; /* must set end_ptr before srandom */
srandom(seed);
__srandom_unlocked(seed);
if (rand_type == TYPE_0)
int_arg_state[0] = rand_type;
else
int_arg_state[0] = MAX_TYPES * (rptr - state) + rand_type;
__random_unlock();
return(ostate);
}
@ -419,6 +440,7 @@ setstate(char *arg_state /* pointer to state array */)
uint32_t rear = new_state[0] / MAX_TYPES;
char *ostate = (char *)(&state[-1]);
__random_lock();
if (rand_type == TYPE_0)
state[-1] = rand_type;
else
@ -443,6 +465,7 @@ setstate(char *arg_state /* pointer to state array */)
fptr = &state[(rear + rand_sep) % rand_deg];
}
end_ptr = &state[rand_deg]; /* set end_ptr too */
__random_unlock();
return(ostate);
}
@ -463,8 +486,8 @@ setstate(char *arg_state /* pointer to state array */)
*
* Returns a 31-bit random number.
*/
long
random()
static long
__random_unlocked()
{
uint32_t i;
uint32_t *f, *r;
@ -491,4 +514,16 @@ random()
}
return((long)i);
}
long
random()
{
long r;
__random_lock();
r = __random_unlocked();
__random_unlock();
return (r);
}
}