#include "types.hh"
#include "util.hh"
#include "affinity.hh"

#if HAVE_SCHED_H
#include <sched.h>
#endif

namespace nix {


#if HAVE_SCHED_SETAFFINITY
static bool didSaveAffinity = false;
static cpu_set_t savedAffinity;
#endif


void setAffinityTo(int cpu)
{
#if HAVE_SCHED_SETAFFINITY
    if (sched_getaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1) return;
    didSaveAffinity = true;
    printMsg(lvlDebug, format("locking this thread to CPU %1%") % cpu);
    cpu_set_t newAffinity;
    CPU_ZERO(&newAffinity);
    CPU_SET(cpu, &newAffinity);
    if (sched_setaffinity(0, sizeof(cpu_set_t), &newAffinity) == -1)
        printMsg(lvlError, format("failed to lock thread to CPU %1%") % cpu);
#endif
}


int lockToCurrentCPU()
{
#if HAVE_SCHED_SETAFFINITY
    int cpu = sched_getcpu();
    if (cpu != -1) setAffinityTo(cpu);
    return cpu;
#else
    return -1;
#endif
}


void restoreAffinity()
{
#if HAVE_SCHED_SETAFFINITY
    if (!didSaveAffinity) return;
    if (sched_setaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1)
        printMsg(lvlError, "failed to restore affinity %1%");
#endif
}


}
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<tr><td><span title='2024-10-24 14:50:09 +0200'>2024-10-24</span></td><td><a href='/guix/commit/build-aux?id=f125143d64c3fac8c9576a55b48331cbf6096460'>build: Restrict access to daemon socket in tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>With the weak isolation available to the test daemon, it is essential to
disallow untrusted access to it, as otherwise another local user can gain our
user's credentials easily.

* build-aux/test-env.in: ensure the daemon-socket directory is freshly-created
  with 0700 permissions.

Change-Id: I742f70fc6fc28e5b4dc88d590eef3daf1b964670
Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Reepca Russelstein</td></tr>
<tr><td><span title='2024-07-18 11:18:29 +0100'>2024-07-18</span></td><td><a href='/guix/commit/build-aux?id=d82ac48b076dca156319c16e78acfadab52fd3e5'>guix: channels: Enable specifiying available builtin builders.</a><span class='msg-avail'>...<span class='msg-tooltip'>When computing channel instance derivations.

This is useful when you want to generate compatible derivations that can be
run with a daemon that potentially doesn't support builtin builders that the
daemon you're using to generate the derivations has.

I'm looking at this in particular because I want to use this in the data
service, since it provides substitutes for derivations, and since these can be
built on other machines, it's useful to control which builtin builders they
depend on.

Fixes: &lt;https://issues.guix.gnu.org/67250&gt;.

* build-aux/build-self.scm (build-program): Accept
 #:built-in-builders and pass along to port-&gt;connection or
open-connection as approriate.
(build): Accept and pass on #:built-in-builders.
* guix/channels.scm (build-from-source, build-channel-instance,
channel-instance-derivations, channel-instances-&gt;manifest,
channel-instances-&gt;derivation): Accept and pass on
 #:built-in-builders.

Change-Id: I315c990de66c6f7dca25a859165a5568abe385ea
</span></span></td><td>Christopher Baines</td></tr>