/* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* The high resolution timer API provides access to the hardware timer * running at around 1.1MHz. The amount this changes in a time slice is * varies randomly due to system events, hardware interrupts etc */ static UCHAR randbyte_hrtimer() { QWORD t1, t2; UCHAR byte; DosTmrQueryTime(&t1); DosSleep(5); DosTmrQueryTime(&t2); byte = (t2.ulLo - t1.ulLo) & 0xFF; byte ^= (t2.ulLo - t1.ulLo) >> 8; return byte; } /* A bunch of system information like memory & process stats. * Not highly random but every bit helps.... */ static UCHAR randbyte_sysinfo() { UCHAR byte = 0; UCHAR SysVars[100]; int b; DosQuerySysInfo(1, QSV_FOREGROUND_PROCESS, SysVars, sizeof(SysVars)); for (b = 0; b < 100; b++) { byte ^= SysVars[b]; } return byte; } /* Similar in concept to randbyte_hrtimer() but accesses the CPU's internal * counters which run at the CPU's MHz speed. We get separate * idle / busy / interrupt cycle counts which should provide very good * randomness due to interference of hardware events. * This only works on newer CPUs (at least PPro or K6) and newer OS/2 versions * which is why it's run-time linked. */ static APIRET APIENTRY(*DosPerfSysCall) (ULONG ulCommand, ULONG ulParm1, ULONG ulParm2, ULONG ulParm3) = NULL; static HMODULE hDoscalls = 0; #define CMD_KI_RDCNT (0x63) typedef struct _CPUUTIL { ULONG ulTimeLow; /* Low 32 bits of time stamp */ ULONG ulTimeHigh; /* High 32 bits of time stamp */ ULONG ulIdleLow; /* Low 32 bits of idle time */ ULONG ulIdleHigh; /* High 32 bits of idle time */ ULONG ulBusyLow; /* Low 32 bits of busy time */ ULONG ulBusyHigh; /* High 32 bits of busy time */ ULONG ulIntrLow; /* Low 32 bits of interrupt time */ ULONG ulIntrHigh; /* High 32 bits of interrupt time */ } CPUUTIL; static UCHAR randbyte_perf() { UCHAR byte = 0; CPUUTIL util; int c; if (hDoscalls == 0) { char failed_module[20]; ULONG rc; rc = DosLoadModule(failed_module, sizeof(failed_module), "DOSCALLS", &hDoscalls); if (rc == 0) { rc = DosQueryProcAddr(hDoscalls, 976, NULL, (PFN *)&DosPerfSysCall); if (rc) { DosPerfSysCall = NULL; } } } if (DosPerfSysCall) { if (DosPerfSysCall(CMD_KI_RDCNT, (ULONG)&util, 0, 0) == 0) { for (c = 0; c < sizeof(util); c++) { byte ^= ((UCHAR *)&util)[c]; } } else { DosPerfSysCall = NULL; } } return byte; } static UCHAR randbyte() { return randbyte_hrtimer() ^ randbyte_sysinfo() ^ randbyte_perf(); }