threadsafe random().

reported by ajacoutot and (much earlier, sorry) by Alexey Suslikov

1 files changed, 43 insertions, 8 deletions

diff --git a/src/lib/libc/stdlib/random.c b/src/lib/libc/stdlib/random.c
index 9c5b9d0f3f..f299d8e2f6 100644
--- a/src/lib/libc/stdlib/random.c
+++ b/src/lib/libc/stdlib/random.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: random.c,v 1.17 2012/06/01 01:01:57 guenther Exp $ */
+/*      $OpenBSD: random.c,v 1.18 2013/03/15 19:07:53 tedu Exp $ */
 /*
  * Copyright (c) 1983 Regents of the University of California.
  * All rights reserved.
@@ -36,6 +36,8 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+#include "thread_private.h"
+
 /*
  * random.c:
  *
@@ -174,6 +176,12 @@ static int rand_type = TYPE_3;
 static int rand_deg = DEG_3;
 static int rand_sep = SEP_3;
 
+_THREAD_PRIVATE_MUTEX(random);
+static long random_l(void);
+
+#define LOCK() _THREAD_PRIVATE_MUTEX_LOCK(random)
+#define UNLOCK() _THREAD_PRIVATE_MUTEX_UNLOCK(random)
+
 /*
  * srandom:
  *
@@ -186,8 +194,8 @@ static int rand_sep = SEP_3;
  * 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 int x)
+static void
+srandom_l(unsigned int x)
 {
         int i;
         int32_t test;
@@ -213,10 +221,18 @@ srandom(unsigned int x)
                 fptr = &state[rand_sep];
                 rptr = &state[0];
                 for (i = 0; i < 10 * rand_deg; i++)
-                        (void)random();
+                        (void)random_l();
         }
 }
 
+void
+srandom(unsigned int x)
+{
+        LOCK();
+        srandom_l(x);
+        UNLOCK();
+}
+
 /*
  * srandomdev:
  *
@@ -234,6 +250,7 @@ srandomdev(void)
         int mib[2];
         size_t len;
 
+        LOCK();
         if (rand_type == TYPE_0)
                 len = sizeof(state[0]);
         else
@@ -247,6 +264,7 @@ srandomdev(void)
                 fptr = &state[rand_sep];
                 rptr = &state[0];
         }
+        UNLOCK();
 }
 
 /*
@@ -273,12 +291,15 @@ initstate(u_int seed, char *arg_state, size_t n)
 {
         char *ostate = (char *)(&state[-1]);
 
+        LOCK();
         if (rand_type == TYPE_0)
                 state[-1] = rand_type;
         else
                 state[-1] = MAX_TYPES * (rptr - state) + rand_type;
-        if (n < BREAK_0)
+        if (n < BREAK_0) {
+                UNLOCK();
                 return(NULL);
+        }
         if (n < BREAK_1) {
                 rand_type = TYPE_0;
                 rand_deg = DEG_0;
@@ -302,11 +323,12 @@ initstate(u_int seed, char *arg_state, size_t n)
         }
         state = &(((int32_t *)arg_state)[1]);   /* first location */
         end_ptr = &state[rand_deg];     /* must set end_ptr before srandom */
-        srandom(seed);
+        srandom_l(seed);
         if (rand_type == TYPE_0)
                 state[-1] = rand_type;
         else
                 state[-1] = MAX_TYPES*(rptr - state) + rand_type;
+        UNLOCK();
         return(ostate);
 }
 
@@ -333,6 +355,7 @@ setstate(char *arg_state)
         int32_t rear = new_state[0] / MAX_TYPES;
         char *ostate = (char *)(&state[-1]);
 
+        LOCK();
         if (rand_type == TYPE_0)
                 state[-1] = rand_type;
         else
@@ -348,6 +371,7 @@ setstate(char *arg_state)
                 rand_sep = seps[type];
                 break;
         default:
+                UNLOCK();
                 return(NULL);
         }
         state = &new_state[1];
@@ -356,6 +380,7 @@ setstate(char *arg_state)
                 fptr = &state[(rear + rand_sep) % rand_deg];
         }
         end_ptr = &state[rand_deg];             /* set end_ptr too */
+        UNLOCK();
         return(ostate);
 }
 
@@ -376,8 +401,8 @@ setstate(char *arg_state)
  *
  * Returns a 31-bit random number.
  */
-long
-random(void)
+static long
+random_l(void)
 {
         int32_t i;
 
@@ -394,3 +419,13 @@ random(void)
         }
         return((long)i);
 }
+
+long
+random(void)
+{
+        long r;
+        LOCK();
+        r = random_l();
+        UNLOCK();
+        return r;
+}