diff options
author | Hans-Christoph Steiner <hans@eds.org> | 2014-10-16 22:51:43 -0400 |
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committer | Hans-Christoph Steiner <hans@eds.org> | 2014-10-16 22:51:43 -0400 |
commit | 9f67c0520ea0d5f11a190197cdf746c512db4ce4 (patch) | |
tree | c88a33f01f20a3d13a09594f114fffacebd0d1a4 /src/random.c | |
parent | ee20336e9c78d2e3782c8d096b9ab4f6ca8ce95f (diff) | |
parent | 569c6676a6ddb0ff73821d7693b5e18ddef809b9 (diff) |
Merge tag 'upstream/3.2.0'
Upstream version 3.2.0
# gpg: Signature made Thu 16 Oct 2014 10:51:39 PM EDT using RSA key ID 374BBE81
# gpg: Good signature from "Hans-Christoph Steiner <hans@guardianproject.info>"
# gpg: aka "Hans-Christoph Steiner <hans@eds.org>"
# gpg: aka "Hans-Christoph Steiner <hans@at.or.at>"
# gpg: aka "[jpeg image of size 5408]"
Diffstat (limited to 'src/random.c')
-rw-r--r-- | src/random.c | 65 |
1 files changed, 23 insertions, 42 deletions
diff --git a/src/random.c b/src/random.c index 234ebdf..b825665 100644 --- a/src/random.c +++ b/src/random.c @@ -28,24 +28,11 @@ static SQLITE_WSD struct sqlite3PrngType { } sqlite3Prng; /* -** Get a single 8-bit random value from the RC4 PRNG. The Mutex -** must be held while executing this routine. -** -** Why not just use a library random generator like lrand48() for this? -** Because the OP_NewRowid opcode in the VDBE depends on having a very -** good source of random numbers. The lrand48() library function may -** well be good enough. But maybe not. Or maybe lrand48() has some -** subtle problems on some systems that could cause problems. It is hard -** to know. To minimize the risk of problems due to bad lrand48() -** implementations, SQLite uses this random number generator based -** on RC4, which we know works very well. -** -** (Later): Actually, OP_NewRowid does not depend on a good source of -** randomness any more. But we will leave this code in all the same. +** Return N random bytes. */ -static u8 randomByte(void){ +void sqlite3_randomness(int N, void *pBuf){ unsigned char t; - + unsigned char *zBuf = pBuf; /* The "wsdPrng" macro will resolve to the pseudo-random number generator ** state vector. If writable static data is unsupported on the target, @@ -60,6 +47,16 @@ static u8 randomByte(void){ # define wsdPrng sqlite3Prng #endif +#if SQLITE_THREADSAFE + sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG); + sqlite3_mutex_enter(mutex); +#endif + + if( N<=0 ){ + wsdPrng.isInit = 0; + sqlite3_mutex_leave(mutex); + return; + } /* Initialize the state of the random number generator once, ** the first time this routine is called. The seed value does @@ -88,29 +85,16 @@ static u8 randomByte(void){ wsdPrng.isInit = 1; } - /* Generate and return single random byte - */ - wsdPrng.i++; - t = wsdPrng.s[wsdPrng.i]; - wsdPrng.j += t; - wsdPrng.s[wsdPrng.i] = wsdPrng.s[wsdPrng.j]; - wsdPrng.s[wsdPrng.j] = t; - t += wsdPrng.s[wsdPrng.i]; - return wsdPrng.s[t]; -} - -/* -** Return N random bytes. -*/ -void sqlite3_randomness(int N, void *pBuf){ - unsigned char *zBuf = pBuf; -#if SQLITE_THREADSAFE - sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG); -#endif - sqlite3_mutex_enter(mutex); - while( N-- ){ - *(zBuf++) = randomByte(); - } + assert( N>0 ); + do{ + wsdPrng.i++; + t = wsdPrng.s[wsdPrng.i]; + wsdPrng.j += t; + wsdPrng.s[wsdPrng.i] = wsdPrng.s[wsdPrng.j]; + wsdPrng.s[wsdPrng.j] = t; + t += wsdPrng.s[wsdPrng.i]; + *(zBuf++) = wsdPrng.s[t]; + }while( --N ); sqlite3_mutex_leave(mutex); } @@ -139,7 +123,4 @@ void sqlite3PrngRestoreState(void){ sizeof(sqlite3Prng) ); } -void sqlite3PrngResetState(void){ - GLOBAL(struct sqlite3PrngType, sqlite3Prng).isInit = 0; -} #endif /* SQLITE_OMIT_BUILTIN_TEST */ |