Changeset 160

Timestamp:

Dec 16, 2008, 4:18:05 AM (17 years ago)

Author:

Paul Smedley

Message:

New implementation of os2_randget() - fixes SIGSEGV with GCC 4.3.2 and -O2 or higher

File:

• branches/samba-3.0/source/lib/os2ea.c (modified) (2 diffs)

branches/samba-3.0/source/lib/os2ea.c

@@ -31 +31 @@
 #define PRINTF_ATTRIBUTE(a1, a2) __attribute__ ((format (__printf__, a1, a2)))
 #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;
 
 #include "local.h"
@@ -108 +97 @@
 }
 
-// very simple random data gatherer derived from openssl
+/* Functions below are based on APR random code */
+/* 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
+ */
+
 void os2_randget(char * buffer, int length)
 {
-        QWORD qwTime;
-        ULONG SysVars[QSV_FOREGROUND_PROCESS];
-        int done = 0;
-
-        if (!buffer || length <= 0)
-        {
-                return;
-        }
-
-        DosTmrQueryTime(&qwTime);
-        memcpy(buffer, &qwTime, sizeof(qwTime) > length ? length : sizeof(qwTime));
-        done += sizeof(qwTime);
-        if (done >= length)
-        {
-                return;
-        }
-
-        if (DosPerfSysCall) 
-        {
-                CPUUTIL util;
-                if (DosPerfSysCall(CMD_KI_RDCNT, (ULONG)&util, 0, 0) == 0) 
-                {
-                        memcpy(buffer + done, &util, sizeof(util) > length - done ? length - done : sizeof(util));
-                        done += sizeof(util);
-                        if (done >= length)
-                        {
-                                return;
-                        }
-                }
-        }
-
-        DosQuerySysInfo(1, QSV_FOREGROUND_PROCESS, SysVars, sizeof(SysVars));
-        memcpy(buffer + done, SysVars, sizeof(SysVars) > length - done ? length - done : sizeof(SysVars));
+    UCHAR randbyte();
+    unsigned int idx;
+
+    for (idx=0; idx<length; idx++)
+        buffer[idx] = randbyte();
+
+}
+
+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 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;
+
+#ifndef __INNOTEK_LIBC__
+    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;
+        }
+    }
+#endif
+    return byte;
+}
+
+
+
+UCHAR randbyte()
+{
+    return randbyte_hrtimer() ^ randbyte_sysinfo() ^ randbyte_perf();
 }