Define size_t.ByReference and fix macOS sysctl size_t* parameters

CHANGES.md

@@ -15,6 +15,7 @@ Features
 Bug Fixes
 ---------
 * [#1343](https://github.com/java-native-access/jna/issues/1343): `c.s.j.p.mac.CoreFoundation.CFStringRef#stringValue` buffer needs space for a null byte - [@dbwiddis](https://github.com/dbwiddis).
+* [#1351](https://github.com/java-native-access/jna/issues/1351): Define `c.s.j.p.unix.size_t.ByReference` and fix macOS sysctl `size_t *` parameters - [@dbwiddis](https://github.com/dbwiddis).
 
 Release 5.8.0
 =============

contrib/platform/src/com/sun/jna/platform/mac/SystemB.java

@@ -623,10 +623,10 @@ class Timezone extends Structure {
      * The sysctl() function retrieves system information and allows processes with
      * appropriate privileges to set system information. The information available
      * from sysctl() consists of integers, strings, and tables.
-     *
+     * <p>
      * The state is described using a "Management Information Base" (MIB) style
      * name, listed in name, which is a namelen length array of integers.
-     *
+     * <p>
      * The information is copied into the buffer specified by oldp. The size of the
      * buffer is given by the location specified by oldlenp before the call, and
      * that location gives the amount of data copied after a successful call and
@@ -635,32 +635,41 @@ class Timezone extends Structure {
      * as much data as fits in the buffer provided and returns with the error code
      * ENOMEM. If the old value is not desired, oldp and oldlenp should be set to
      * NULL.
-     *
+     * <p>
      * The size of the available data can be determined by calling sysctl() with the
      * NULL argument for oldp. The size of the available data will be returned in
      * the location pointed to by oldlenp. For some operations, the amount of space
      * may change often. For these operations, the system attempts to round up so
      * that the returned size is large enough for a call to return the data shortly
      * thereafter.
-     *
+     * <p>
      * To set a new value, newp is set to point to a buffer of length newlen from
      * which the requested value is to be taken. If a new value is not to be set,
      * newp should be set to NULL and newlen set to 0.
      *
      * @param name
-     *            MIB array of integers
+     *            a Management Information Base (MIB) array of integers
      * @param namelen
-     *            length of the MIB array
+     *            the length of the array in {@code name}
      * @param oldp
-     *            Information retrieved
+     *            A buffer to hold the information retrieved
      * @param oldlenp
-     *            Size of information retrieved
+     *            Size of the buffer, a pointer to a {@link size_t} value
      * @param newp
-     *            Information to be written
+     *            To set a new value, a buffer of information to be written. May be
+     *            null if no value is to be set.
      * @param newlen
-     *            Size of information to be written
+     *            Size of the information to be written. May be 0 if no value is to
+     *            be set.
      * @return 0 on success; sets errno on failure
      */
+    int sysctl(int[] name, int namelen, Pointer oldp, size_t.ByReference oldlenp, Pointer newp, size_t newlen);
+
+    /**
+     * @deprecated Use
+     *             {@link #sysctl(int[], int, Pointer, Pointer, Pointer, com.sun.jna.platform.unix.LibCAPI.size_t)}
+     */
+    @Deprecated
     int sysctl(int[] name, int namelen, Pointer oldp, IntByReference oldlenp, Pointer newp, int newlen);
 
     /**
@@ -671,15 +680,24 @@ class Timezone extends Structure {
      * @param name
      *            ASCII representation of the MIB name
      * @param oldp
-     *            Information retrieved
+     *            A buffer to hold the information retrieved
      * @param oldlenp
-     *            Size of information retrieved
+     *            Size of the buffer, a pointer to a {@link size_t} value
      * @param newp
-     *            Information to be written
+     *            To set a new value, a buffer of information to be written. May be
+     *            null if no value is to be set.
      * @param newlen
-     *            Size of information to be written
+     *            Size of the information to be written. May be 0 if no value is to
+     *            be set.
      * @return 0 on success; sets errno on failure
      */
+    int sysctlbyname(String name, Pointer oldp, size_t.ByReference oldlenp, Pointer newp, size_t newlen);
+
+    /**
+     * @deprecated Use
+     *             {@link #sysctlbyname(String, Pointer, Pointer, Pointer, com.sun.jna.platform.unix.LibCAPI.size_t)}
+     */
+    @Deprecated
     int sysctlbyname(String name, Pointer oldp, IntByReference oldlenp, Pointer newp, int newlen);
 
     /**
@@ -705,12 +723,18 @@ class Timezone extends Structure {
      *            ASCII representation of the name
      * @param mibp
      *            Integer array containing the corresponding name vector.
-     * @param size
+     * @param sizep
      *            On input, number of elements in the returned array; on output, the
      *            number of entries copied.
      * @return 0 on success; sets errno on failure
      */
-    int sysctlnametomib(String name, Pointer mibp, IntByReference size);
+    int sysctlnametomib(String name, Pointer mibp, size_t.ByReference sizep);
+
+    /**
+     * @deprecated Use {@link #sysctlnametomib(String, Pointer, Pointer)}
+     */
+    @Deprecated
+    int sysctlnametomib(String name, Pointer mibp, IntByReference sizep);
 
     /**
      * The host_processor_info function returns information about processors.

contrib/platform/src/com/sun/jna/platform/unix/LibCAPI.java

@@ -1,4 +1,4 @@
-/* Copyright (c) 2015 Goldstein Lyor, All Rights Reserved
+/* Copyright (c) 2015 Goldstein Lyor, 2021 Daniel Widdis, All Rights Reserved
  *
  * The contents of this file is dual-licensed under 2
  * alternative Open Source/Free licenses: LGPL 2.1 or later and
@@ -43,6 +43,33 @@ class size_t extends IntegerType {
 
         private static final long serialVersionUID = 1L;
 
+        public static class ByReference extends com.sun.jna.ptr.ByReference {
+            public ByReference() {
+                this(0);
+            }
+
+            public ByReference(long value) {
+                this(new size_t(value));
+            }
+
+            public ByReference(size_t value) {
+                super(Native.SIZE_T_SIZE);
+                setValue(value);
+            }
+
+            public void setValue(size_t value) {
+                if (Native.SIZE_T_SIZE > 4) {
+                    getPointer().setLong(0, value.longValue());
+                } else {
+                    getPointer().setInt(0, value.intValue());
+                }
+            }
+
+            public size_t getValue() {
+                return new size_t(Native.SIZE_T_SIZE > 4 ? getPointer().getLong(0) : getPointer().getInt(0));
+            }
+        }
+
         public size_t() {
             this(0);
         }

contrib/platform/test/com/sun/jna/platform/mac/SystemBTest.java

@@ -54,7 +54,7 @@
 import com.sun.jna.ptr.PointerByReference;
 
 import junit.framework.TestCase;
-
+import static com.sun.jna.platform.unix.LibCAPI.size_t;
 /**
  * Exercise the {@link SystemB} class.
  */
@@ -64,33 +64,39 @@ public void testSysctl() {
         final String mibName = "hw.logicalcpu";
         final int nCpu = Runtime.getRuntime().availableProcessors();
 
-        IntByReference size = new IntByReference(SystemB.INT_SIZE);
-        Pointer p = new Memory(size.getValue());
-        int ret = SystemB.INSTANCE.sysctlbyname(mibName, p, size, null, 0);
-        assertEquals(ret, 0);
+        // This sysctl returns a 32-bit integer cpu count
+        size_t size = new size_t(Integer.BYTES);
+        Pointer p = new Memory(size.longValue());
+        size_t.ByReference plen = new size_t.ByReference(size);
+        assertEquals(0, SystemB.INSTANCE.sysctlbyname(mibName, p, plen, null, size_t.ZERO));
         // These values should be equal unless affinity is set, limiting nCpu
         assertTrue(p.getInt(0) >= nCpu);
 
-        size = new IntByReference();
-        ret = SystemB.INSTANCE.sysctlnametomib(mibName, null, size);
-        assertEquals(ret, 0);
-        // Size should be 2
-        assertEquals(size.getValue(), 2);
-
-        Pointer mibp = new Memory(size.getValue() * SystemB.INT_SIZE);
-        ret = SystemB.INSTANCE.sysctlnametomib(mibName, mibp, size);
-        assertEquals(ret, 0);
-        // Size should be 2
-        assertEquals(size.getValue(), 2);
-
-        int[] mib = mibp.getIntArray(0, size.getValue());
+        // Get the same value by converting the string to the MIB array
+        // Get the size of the MIB array
+        size = new size_t(Integer.BYTES);
+        size_t.ByReference sizep = new size_t.ByReference(size);
+        assertEquals(0, SystemB.INSTANCE.sysctlnametomib(mibName, null, sizep));
+        // Array size should be 2
+        int sizepval = sizep.getValue().intValue();
+        assertEquals(2, sizepval);
+
+        // Allocate the correct size and fill the MIB array
+        Pointer mibp = new Memory(sizepval * SystemB.INT_SIZE);
+        assertEquals(0, SystemB.INSTANCE.sysctlnametomib(mibName, mibp, sizep));
+        // Array size should still be 2
+        sizepval = sizep.getValue().intValue();
+        assertEquals(2, sizepval);
+
+        int[] mib = mibp.getIntArray(0, sizepval);
         // mib should be { 6, 103(?) }
         assertEquals(mib.length, 2);
         assertEquals(mib[0], 6);
 
-        size = new IntByReference(SystemB.INT_SIZE);
-        p = new Memory(size.getValue());
-        ret = SystemB.INSTANCE.sysctl(mib, mib.length, p, size, null, 0);
+        size = new size_t(Integer.BYTES);
+        p = new Memory(size.longValue());
+        plen = new size_t.ByReference(size);
+        assertEquals(0, SystemB.INSTANCE.sysctl(mib, mib.length, p, plen, null, size_t.ZERO));
         assertTrue(p.getInt(0) >= nCpu);
     }
 
@@ -257,16 +263,16 @@ public void testStatfs() {
     public void testXswUsage() {
         XswUsage xswUsage = new XswUsage();
         assertEquals(0, SystemB.INSTANCE.sysctlbyname("vm.swapusage", xswUsage.getPointer(),
-                new IntByReference(xswUsage.size()), null, 0));
+                new size_t.ByReference(xswUsage.size()), null, size_t.ZERO));
         xswUsage.read();
         assertTrue(xswUsage.xsu_used <= xswUsage.xsu_total);
     }
 
     public void testProcessStructures() {
         // Calc max # of processes
-        IntByReference size = new IntByReference(4);
+        size_t.ByReference size = new size_t.ByReference(4);
         Memory mem = new Memory(4);
-        assertEquals(0, SystemB.INSTANCE.sysctlbyname("kern.maxproc", mem, size, null, 0));
+        assertEquals(0, SystemB.INSTANCE.sysctlbyname("kern.maxproc", mem, size, null, size_t.ZERO));
         int maxProc = mem.getInt(0);
 
         // Get list of pids
@@ -330,15 +336,15 @@ public void testIFs() {
         int NET_RT_IFLIST2 = 6;
         int[] mib = { CTL_NET, PF_ROUTE, 0, 0, NET_RT_IFLIST2, 0 };
 
-        IntByReference len = new IntByReference();
-        assertEquals(0, SystemB.INSTANCE.sysctl(mib, 6, null, len, null, 0));
+        size_t.ByReference len = new size_t.ByReference();
+        assertEquals(0, SystemB.INSTANCE.sysctl(mib, 6, null, len, null, size_t.ZERO));
         // Add enough room for max size of IFmsgHdr to avoid JNA bounds check
         // problems with worst case structure size
-        Memory buf = new Memory(len.getValue() + 112);
-        assertEquals(0, SystemB.INSTANCE.sysctl(mib, 6, buf, len, null, 0));
+        Memory buf = new Memory(len.getValue().longValue() + 112);
+        assertEquals(0, SystemB.INSTANCE.sysctl(mib, 6, buf, len, null, size_t.ZERO));
 
         // Iterate offset from buf's pointer up to limit of buf
-        int lim = len.getValue();
+        int lim = len.getValue().intValue();
         int next = 0;
         while (next < lim) {
             // Get pointer to current native part of buf