forked from Mirrors/freeswitch
0488a5109a
git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3733 d0543943-73ff-0310-b7d9-9358b9ac24b2
124 lines
3.6 KiB
C++
124 lines
3.6 KiB
C++
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* The high resolution timer API provides access to the hardware timer
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* running at around 1.1MHz. The amount this changes in a time slice is
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* varies randomly due to system events, hardware interrupts etc
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*/
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static UCHAR randbyte_hrtimer()
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{
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QWORD t1, t2;
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UCHAR byte;
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DosTmrQueryTime(&t1);
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DosSleep(5);
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DosTmrQueryTime(&t2);
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byte = (t2.ulLo - t1.ulLo) & 0xFF;
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byte ^= (t2.ulLo - t1.ulLo) >> 8;
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return byte;
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}
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/* A bunch of system information like memory & process stats.
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* Not highly random but every bit helps....
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*/
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static UCHAR randbyte_sysinfo()
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{
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UCHAR byte = 0;
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UCHAR SysVars[100];
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int b;
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DosQuerySysInfo(1, QSV_FOREGROUND_PROCESS, SysVars, sizeof(SysVars));
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for (b = 0; b < 100; b++) {
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byte ^= SysVars[b];
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}
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return byte;
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}
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/* Similar in concept to randbyte_hrtimer() but accesses the CPU's internal
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* counters which run at the CPU's MHz speed. We get separate
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* idle / busy / interrupt cycle counts which should provide very good
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* randomness due to interference of hardware events.
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* This only works on newer CPUs (at least PPro or K6) and newer OS/2 versions
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* which is why it's run-time linked.
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*/
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static APIRET APIENTRY(*DosPerfSysCall) (ULONG ulCommand, ULONG ulParm1,
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ULONG ulParm2, ULONG ulParm3) = NULL;
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static HMODULE hDoscalls = 0;
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#define CMD_KI_RDCNT (0x63)
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typedef struct _CPUUTIL {
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ULONG ulTimeLow; /* Low 32 bits of time stamp */
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ULONG ulTimeHigh; /* High 32 bits of time stamp */
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ULONG ulIdleLow; /* Low 32 bits of idle time */
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ULONG ulIdleHigh; /* High 32 bits of idle time */
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ULONG ulBusyLow; /* Low 32 bits of busy time */
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ULONG ulBusyHigh; /* High 32 bits of busy time */
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ULONG ulIntrLow; /* Low 32 bits of interrupt time */
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ULONG ulIntrHigh; /* High 32 bits of interrupt time */
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} CPUUTIL;
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static UCHAR randbyte_perf()
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{
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UCHAR byte = 0;
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CPUUTIL util;
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int c;
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if (hDoscalls == 0) {
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char failed_module[20];
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ULONG rc;
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rc = DosLoadModule(failed_module, sizeof(failed_module), "DOSCALLS",
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&hDoscalls);
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if (rc == 0) {
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rc = DosQueryProcAddr(hDoscalls, 976, NULL, (PFN *)&DosPerfSysCall);
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if (rc) {
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DosPerfSysCall = NULL;
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}
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}
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}
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if (DosPerfSysCall) {
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if (DosPerfSysCall(CMD_KI_RDCNT, (ULONG)&util, 0, 0) == 0) {
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for (c = 0; c < sizeof(util); c++) {
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byte ^= ((UCHAR *)&util)[c];
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}
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}
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else {
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DosPerfSysCall = NULL;
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}
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}
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return byte;
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}
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static UCHAR randbyte()
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{
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return randbyte_hrtimer() ^ randbyte_sysinfo() ^ randbyte_perf();
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}
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