Sorry about the mega-patch.

This is a work-in-progress, code is currently broken.
(Some actions, and notably, the header, are missing.)

Affinity.c

@@ -9,9 +9,18 @@ in the source distribution for its full text.
 
 #include <stdlib.h>
 
+#ifdef HAVE_LIBHWLOC
+#include <hwloc/linux.h>
+#elif HAVE_NATIVE_AFFINITY
+#include <sched.h>
+#endif
+
 /*{
+#include "Process.h"
+#include "ProcessList.h"
 
 typedef struct Affinity_ {
+   ProcessList* pl;
    int size;
    int used;
    int* cpus;
@@ -19,10 +28,11 @@ typedef struct Affinity_ {
 
 }*/
 
-Affinity* Affinity_new() {
+Affinity* Affinity_new(ProcessList* pl) {
    Affinity* this = calloc(1, sizeof(Affinity));
    this->size = 8;
    this->cpus = calloc(this->size, sizeof(int));
+   this->pl = pl;
    return this;
 }
 
@@ -40,3 +50,62 @@ void Affinity_add(Affinity* this, int id) {
    this->used++;
 }
 
+
+#ifdef HAVE_LIBHWLOC
+
+Affinity* Affinity_get(Process* proc, ProcessList* pl) {
+   hwloc_cpuset_t cpuset = hwloc_bitmap_alloc();
+   bool ok = (hwloc_linux_get_tid_cpubind(pl->topology, proc->pid, cpuset) == 0);
+   Affinity* affinity = NULL;
+   if (ok) {
+      affinity = Affinity_new(pl);
+      if (hwloc_bitmap_last(cpuset) == -1) {
+         for (int i = 0; i < pl->cpuCount; i++) {
+            Affinity_add(affinity, i);
+         }
+      } else {
+         unsigned int id;
+         hwloc_bitmap_foreach_begin(id, cpuset);
+            Affinity_add(affinity, id);
+         hwloc_bitmap_foreach_end();
+      }
+   }
+   hwloc_bitmap_free(cpuset);
+   return affinity;
+}
+
+bool Affinity_set(Process* proc, Affinity* this) {
+   hwloc_cpuset_t cpuset = hwloc_bitmap_alloc();
+   for (int i = 0; i < affinity->used; i++) {
+      hwloc_bitmap_set(cpuset, affinity->cpus[i]);
+   }
+   bool ok = (hwloc_linux_set_tid_cpubind(this->pl->topology, proc->pid, cpuset) == 0);
+   hwloc_bitmap_free(cpuset);
+   return ok;
+}
+
+#elif HAVE_NATIVE_AFFINITY
+
+Affinity* Affinity_get(Process* proc, ProcessList* pl) {
+   cpu_set_t cpuset;
+   bool ok = (sched_getaffinity(proc->pid, sizeof(cpu_set_t), &cpuset) == 0);
+   if (!ok) return NULL;
+   Affinity* affinity = Affinity_new(pl);
+   for (int i = 0; i < pl->cpuCount; i++) {
+      if (CPU_ISSET(i, &cpuset))
+         Affinity_add(affinity, i);
+   }
+   return affinity;
+}
+
+bool Affinity_set(Process* proc, Affinity* this) {
+   cpu_set_t cpuset;
+   CPU_ZERO(&cpuset);
+   for (int i = 0; i < this->used; i++) {
+      CPU_SET(this->cpus[i], &cpuset);
+   }
+   bool ok = (sched_setaffinity(proc->pid, sizeof(unsigned long), &cpuset) == 0);
+   return ok;
+}
+
+#endif