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* [newlib-cygwin/cygwin-3_4-branch] Cygwin: random: make random(3) functions thread-safe
@ 2023-11-13 19:03 Corinna Vinschen
0 siblings, 0 replies; only message in thread
From: Corinna Vinschen @ 2023-11-13 19:03 UTC (permalink / raw)
To: cygwin-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=6461906beb86c4583eb4e3f8bb1ed03221277f3e
commit 6461906beb86c4583eb4e3f8bb1ed03221277f3e
Author: Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Mon Nov 13 19:41:08 2023 +0100
Commit: Corinna Vinschen <corinna@vinschen.de>
CommitDate: Mon Nov 13 19:52:37 2023 +0100
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>
Diff:
---
winsup/cygwin/random.cc | 47 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 41 insertions(+), 6 deletions(-)
diff --git a/winsup/cygwin/random.cc b/winsup/cygwin/random.cc
index 163fc040cef5..b38fdc078189 100644
--- a/winsup/cygwin/random.cc
+++ b/winsup/cygwin/random.cc
@@ -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();
}
/*
@@ -350,6 +368,7 @@ 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
@@ -358,6 +377,7 @@ 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) {
@@ -383,11 +403,12 @@ 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);
}
@@ -418,6 +439,7 @@ 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
@@ -442,6 +464,7 @@ 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);
}
@@ -462,8 +485,8 @@ 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;
@@ -490,4 +513,16 @@ random()
}
return((long)i);
}
+
+long
+random()
+{
+ long r;
+
+ __random_lock();
+ r = __random_unlocked();
+ __random_unlock();
+ return (r);
+}
+
}
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