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Add locking so that arc4random(3) functions are all reentrant for

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pthreads.

Submitted by:	Christian S.J. Peron <maneo@bsdpro.com>
This commit is contained in:
Brian Feldman 2004-03-24 14:44:57 +00:00
parent 67e4206588
commit 5295209eff
1 changed files with 54 additions and 10 deletions
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64
lib/libc/gen/arc4random.c
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@ -32,6 +32,9 @@ __FBSDID("$FreeBSD$");
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include "libc_private.h"
#include "un-namespace.h"
struct arc4_stream {
@ -40,10 +43,27 @@ struct arc4_stream {
u_int8_t s[256];
};
static int rs_initialized;
static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
#define RANDOMDEV "/dev/urandom"
#define THREAD_LOCK() \
do { \
if (__isthreaded) \
_pthread_mutex_lock(&arc4random_mtx); \
} while (0)
#define THREAD_UNLOCK() \
do { \
if (__isthreaded) \
_pthread_mutex_unlock(&arc4random_mtx); \
} while (0)
static struct arc4_stream rs;
static int rs_initialized;
static int rs_stired;
static inline u_int8_t arc4_getbyte(struct arc4_stream *);
static void arc4_stir(struct arc4_stream *);
static inline void
arc4_init(as)
@ -89,11 +109,11 @@ arc4_stir(as)
gettimeofday(&rdat.tv, NULL);
rdat.pid = getpid();
fd = _open("/dev/urandom", O_RDONLY, 0);
fd = _open(RANDOMDEV, O_RDONLY, 0);
if (fd >= 0) {
(void) _read(fd, rdat.rnd, sizeof(rdat.rnd));
_close(fd);
}
}
/* fd < 0? Ah, what the heck. We'll just take whatever was on the
* stack... */
@ -140,14 +160,31 @@ arc4_getword(as)
return (val);
}
void
arc4random_stir()
static void
arc4_check_init(void)
{
if (!rs_initialized) {
arc4_init(&rs);
rs_initialized = 1;
}
}
static void
arc4_check_stir(void)
{
if (!rs_stired) {
arc4_stir(&rs);
rs_stired = 1;
}
}
void
arc4random_stir()
{
THREAD_LOCK();
arc4_check_init();
arc4_stir(&rs);
THREAD_UNLOCK();
}
void
@ -155,18 +192,25 @@ arc4random_addrandom(dat, datlen)
u_char *dat;
int datlen;
{
if (!rs_initialized)
arc4random_stir();
THREAD_LOCK();
arc4_check_init();
arc4_check_stir();
arc4_addrandom(&rs, dat, datlen);
THREAD_UNLOCK();
}
u_int32_t
arc4random()
{
if (!rs_initialized)
arc4random_stir();
u_int32_t rnd;
return (arc4_getword(&rs));
THREAD_LOCK();
arc4_check_init();
arc4_check_stir();
rnd = arc4_getword(&rs);
THREAD_UNLOCK();
return (rnd);
}
#if 0