From: drh Date: Sat, 9 Sep 2017 08:03:28 +0000 (+0000) Subject: Use a mutex-free PRNG for the random() and randomblob() SQL functions and for X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d351e7643f04d2df346ba4729eed331b8874ceb5;p=thirdparty%2Fsqlite.git Use a mutex-free PRNG for the random() and randomblob() SQL functions and for the randomness used during checkpoint operations. FossilOrigin-Name: e63d1a7cd317811f74d206ae47bd11a8fc6b6311218fbc6d0cbf49e8281b362f --- diff --git a/manifest b/manifest index 4b71f03671..494f65db2e 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Fix\sharmless\scompiler\swarnings\sseen\swith\sMSVC. -D 2017-09-09T00:51:36.496 +C Use\sa\smutex-free\sPRNG\sfor\sthe\srandom()\sand\srandomblob()\sSQL\sfunctions\sand\sfor\nthe\srandomness\sused\sduring\scheckpoint\soperations. +D 2017-09-09T08:03:28.579 F Makefile.in c644bbe8ebe4aae82ad6783eae6b6beea4c727b99ff97568b847ced5e2ac7afb F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434 F Makefile.msc 6a7a74bf60ad395098c0bd175ab054cd65ef85d7f034198d52bcc4d9e5fb4c6b @@ -413,7 +413,7 @@ F src/delete.c 21a5f1812fdb599e9f7afb9f650bdabab60a3afd51d7e94e539c982f647b0023 F src/expr.c 0f611840217016cf2c5e72f2eb8e412e48511bf740ae1fd5b58dc5e409c6e738 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007 F src/fkey.c 5ff2c895fe087756d8085dc1a9bc229b5670e2a65c3929dd87c71e43649af333 -F src/func.c b4d259af627e3cd9510cf08db37f0bcc88b1887c735169c74490c3739d5cf5c6 +F src/func.c 8c46246dcb5779e77bf2ef192fa1355460aeec1d3d0b2537608d319bcd7d8778 F src/global.c ac3094f1dc59fbeb919aef7cc0cc827a8459d1fb1adb7972ef75bd9e0c10b75b F src/hash.c a12580e143f10301ed5166ea4964ae2853d3905a511d4e0c44497245c7ce1f7a F src/hash.h ab34c5c54a9e9de2e790b24349ba5aab3dbb4fd4 @@ -422,7 +422,7 @@ F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71 F src/insert.c d2d1bf12d2b5382450620d7cede84c7ffe57e6a89fa9a908f1aba68df2731cd9 F src/legacy.c 134ab3e3fae00a0f67a5187981d6935b24b337bcf0f4b3e5c9fa5763da95bf4e F src/loadext.c 20865b183bb8a3723d59cf1efffc3c50217eb452c1021d077b908c94da26b0b2 -F src/main.c 34a58563358fe40979186124d1a3614b9a00c833124d7ebfa8e5d604ed1d2521 +F src/main.c cd03aeca7a9d5f221010d0212b3abdd558e37a317947f8e78dd9162a5d904223 F src/malloc.c a02c9e69bc76bee0f639416b947a946412890b606301454727feadcb313536d6 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645 F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de @@ -454,16 +454,16 @@ F src/pragma.c faf5f9ec553b71035c63e08d31651bbd28bec826d546b32c8e9c295855ca3605 F src/pragma.h bb83728944b42f6d409c77f5838a8edbdb0fe83046c5496ffc9602b40340a324 F src/prepare.c 9a141a1b02dca53beaa9771699d390aafcac01f5d1f1c0ae6e23ded8dcdb709a F src/printf.c 40aee47ae9be4bd3dbdc8968bd07fddc027be8edec8daddf24d3391d36698a1c -F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384 +F src/random.c f27af4099afaea7284ade5c206224dcfdb2334cfd119d018b470d46356b3f27d F src/resolve.c 4324a94573b1e29286f8121e4881db59eaedc014afeb274c8d3e07ed282e0e20 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac -F src/select.c c9b3d8444bbf6f167d84f41ca6f3672e2521cb163a8c706b19058dc82fffe9b8 +F src/select.c 5bda89e7cda69ef9cdd25c98ee6403ed2a3753d5ab135e24fc7a20344fd68d0a F src/shell.c c1206a23d9239f8f51751d3be9b8c3b02fa4103546bea1add7f864d84a8276ab F src/shell.c.in bb9720a8c5c98d3984b16ab7540e7142bcae959666ecf248bfc523a1d44220ee F src/sqlite.h.in 21f62793a3611b43f6fb31f0a4c8b38489a4df025416e9b7db7cc01bf5ef5aaa F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8 F src/sqlite3ext.h a1fd3aa82f967da436164e0728a7d6841651fd0c6e27b9044e0eb9f6c8462e47 -F src/sqliteInt.h f9ae3609a583aa51712083e1d5817f62c7d97c0a203036a9a62c439059e8258b +F src/sqliteInt.h 63e64c24f19910f52d2910f000b070a027fad42d134055970c98c18a76584fce F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b F src/status.c 9737ed017279a9e0c5da748701c3c7bf1e8ae0dae459aad20dd64fcff97a7e35 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34 @@ -536,7 +536,7 @@ F src/vdbesort.c 731a09e5cb9e96b70c394c1b7cf3860fbe84acca7682e178615eb941a3a0ef2 F src/vdbetrace.c 48e11ebe040c6b41d146abed2602e3d00d621d7ebe4eb29b0a0f1617fd3c2f6c F src/vtab.c f1d5c23132fb0247af3e86146404112283ddedb6c518de0d4edc91cfb36970ef F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9 -F src/wal.c 839db09792fead5052bb35e533fa485e134913d547d05b5f42e537b73e63f07a +F src/wal.c 2a205ec9c9be4e4b2933d32481c4654b4c6b644d8a6c755a5f8c7a10ade64616 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a F src/walker.c 3ccfa8637f95355bff61144e01a615b8ef26f79c312880848da73f03367da1e6 F src/where.c 101f0a645c45c12141b38a61b593232555fc001bf7786dcb03eb8f313783b404 @@ -1652,7 +1652,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P e1e3ca7ea43a68b9b57dc38d8855f63b63a53feb8128b666a1becf87a2c70341 -R 14621bd82abfa0f650a4c6242c2108d7 -U mistachkin -Z 11f83c8a0999c8fee516d7917728daf2 +P faa22e29a5a05a16d46a428d838acedfa7d6fad6239495d59a6a1f4764e1b1b6 +R a52f584275f92dc78c3958a57a4f1fc7 +T *branch * mutex-free-randomness +T *sym-mutex-free-randomness * +T -sym-trunk * +U drh +Z fc9d4eaa55f9d67c6518af204f0991ab diff --git a/manifest.uuid b/manifest.uuid index ce2953ddb7..99d7c5ea83 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -faa22e29a5a05a16d46a428d838acedfa7d6fad6239495d59a6a1f4764e1b1b6 \ No newline at end of file +e63d1a7cd317811f74d206ae47bd11a8fc6b6311218fbc6d0cbf49e8281b362f \ No newline at end of file diff --git a/src/func.c b/src/func.c index b46578a407..f2ed1faae6 100644 --- a/src/func.c +++ b/src/func.c @@ -481,8 +481,9 @@ static void randomFunc( sqlite3_value **NotUsed2 ){ sqlite_int64 r; + sqlite3 *db = sqlite3_context_db_handle(context); UNUSED_PARAMETER2(NotUsed, NotUsed2); - sqlite3_randomness(sizeof(r), &r); + sqlite3FastRandomness(&db->sPrng, sizeof(r), &r); if( r<0 ){ /* We need to prevent a random number of 0x8000000000000000 ** (or -9223372036854775808) since when you do abs() of that @@ -508,6 +509,7 @@ static void randomBlob( ){ int n; unsigned char *p; + sqlite3 *db = sqlite3_context_db_handle(context); assert( argc==1 ); UNUSED_PARAMETER(argc); n = sqlite3_value_int(argv[0]); @@ -516,7 +518,7 @@ static void randomBlob( } p = contextMalloc(context, n); if( p ){ - sqlite3_randomness(n, p); + sqlite3FastRandomness(&db->sPrng, n, p); sqlite3_result_blob(context, (char*)p, n, sqlite3_free); } } diff --git a/src/main.c b/src/main.c index 3942ed9465..2a83e05539 100644 --- a/src/main.c +++ b/src/main.c @@ -2865,6 +2865,7 @@ static int openDatabase( db->nDb = 2; db->magic = SQLITE_MAGIC_BUSY; db->aDb = db->aDbStatic; + sqlite3FastPrngInit(&db->sPrng); assert( sizeof(db->aLimit)==sizeof(aHardLimit) ); memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit)); diff --git a/src/random.c b/src/random.c index d4ae77c435..dd971ab655 100644 --- a/src/random.c +++ b/src/random.c @@ -106,6 +106,28 @@ void sqlite3_randomness(int N, void *pBuf){ sqlite3_mutex_leave(mutex); } +/* +** Initialize a fast PRNG. A Fast PRNG is called "fast" because it does +** not need a mutex to operate, though it does use a mutex to initialize. +** The quality of the randomness is not as good as the global PRNG. +*/ +void sqlite3FastPrngInit(FastPrng *pPrng){ + sqlite3_randomness(sizeof(*pPrng), pPrng); + pPrng->x |= 1; +} + +/* +** Generate N bytes of pseudo-randomness using a FastPrng +*/ +void sqlite3FastRandomness(FastPrng *pPrng, int N, void *P){ + unsigned char *pOut = (unsigned char*)P; + while( N-->0 ){ + pPrng->x = ((pPrng->x)>>1) ^ ((1+~((pPrng->x)&1)) & 0xd0000001); + pPrng->y = (pPrng->y)*1103515245 + 12345; + *(pOut++) = (pPrng->x ^ pPrng->y) & 0xff; + } +} + #ifndef SQLITE_UNTESTABLE /* ** For testing purposes, we sometimes want to preserve the state of diff --git a/src/select.c b/src/select.c index aedbcc4b3a..2b2f687a5b 100644 --- a/src/select.c +++ b/src/select.c @@ -1745,7 +1745,7 @@ int sqlite3ColumnsFromExprList( if( zName[j]==':' ) nName = j; } zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt); - if( cnt>3 ) sqlite3_randomness(sizeof(cnt), &cnt); + if( cnt>3 ) sqlite3FastRandomness(&db->sPrng, sizeof(cnt), &cnt); } pCol->zName = zName; sqlite3ColumnPropertiesFromName(0, pCol); diff --git a/src/sqliteInt.h b/src/sqliteInt.h index 4ce54cf73d..1b254e2512 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -1073,6 +1073,7 @@ typedef struct NameContext NameContext; typedef struct Parse Parse; typedef struct PreUpdate PreUpdate; typedef struct PrintfArguments PrintfArguments; +typedef struct FastPrng FastPrng; typedef struct RowSet RowSet; typedef struct Savepoint Savepoint; typedef struct Select Select; @@ -1145,6 +1146,14 @@ typedef int VList; # define SQLITE_DEFAULT_WAL_SYNCHRONOUS SQLITE_DEFAULT_SYNCHRONOUS #endif +/* +** State of a simple PRNG used for the per-connection and per-pager +** pseudo-random number generators. +*/ +struct FastPrng { + unsigned int x, y; +}; + /* ** Each database file to be accessed by the system is an instance ** of the following structure. There are normally two of these structures @@ -1351,6 +1360,7 @@ struct sqlite3 { u8 nSqlExec; /* Number of pending OP_SqlExec opcodes */ int nextPagesize; /* Pagesize after VACUUM if >0 */ u32 magic; /* Magic number for detect library misuse */ + FastPrng sPrng; /* State of the per-connection PRNG */ int nChange; /* Value returned by sqlite3_changes() */ int nTotalChange; /* Value returned by sqlite3_total_changes() */ int aLimit[SQLITE_N_LIMIT]; /* Limits */ @@ -3821,6 +3831,8 @@ Vdbe *sqlite3GetVdbe(Parse*); void sqlite3PrngSaveState(void); void sqlite3PrngRestoreState(void); #endif +void sqlite3FastPrngInit(FastPrng*); +void sqlite3FastRandomness(FastPrng*, int N, void *P); void sqlite3RollbackAll(sqlite3*,int); void sqlite3CodeVerifySchema(Parse*, int); void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb); diff --git a/src/wal.c b/src/wal.c index 9930b84421..1353766f7f 100644 --- a/src/wal.c +++ b/src/wal.c @@ -448,6 +448,7 @@ struct Wal { u32 iReCksum; /* On commit, recalculate checksums from here */ const char *zWalName; /* Name of WAL file */ u32 nCkpt; /* Checkpoint sequence counter in the wal-header */ + FastPrng sPrng; /* Random number generator */ #ifdef SQLITE_DEBUG u8 lockError; /* True if a locking error has occurred */ #endif @@ -1323,6 +1324,7 @@ int sqlite3WalOpen( pRet->syncHeader = 1; pRet->padToSectorBoundary = 1; pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE); + sqlite3FastPrngInit(&pRet->sPrng); /* Open file handle on the write-ahead log file. */ flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL); @@ -1870,7 +1872,7 @@ static int walCheckpoint( rc = SQLITE_BUSY; }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){ u32 salt1; - sqlite3_randomness(4, &salt1); + sqlite3FastRandomness(&pWal->sPrng, 4, &salt1); assert( pInfo->nBackfill==pWal->hdr.mxFrame ); rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1); if( rc==SQLITE_OK ){ @@ -2878,7 +2880,7 @@ static int walRestartLog(Wal *pWal){ assert( pInfo->nBackfill==pWal->hdr.mxFrame ); if( pInfo->nBackfill>0 ){ u32 salt1; - sqlite3_randomness(4, &salt1); + sqlite3FastRandomness(&pWal->sPrng, 4, &salt1); rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1); if( rc==SQLITE_OK ){ /* If all readers are using WAL_READ_LOCK(0) (in other words if no @@ -3094,7 +3096,7 @@ int sqlite3WalFrames( sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION); sqlite3Put4byte(&aWalHdr[8], szPage); sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt); - if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt); + if( pWal->nCkpt==0 ) sqlite3FastRandomness(&pWal->sPrng, 8, pWal->hdr.aSalt); memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8); walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum); sqlite3Put4byte(&aWalHdr[24], aCksum[0]);