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boundary="------------CWlN6Dx403tuLcg6YEJPHBn2"; protected-headers="v1" From: Maxime Devos To: =?UTF-8?Q?Ludovic_Court=c3=a8s?= Cc: 56674@debbugs.gnu.org Message-ID: Subject: =?UTF-8?B?UmU6IGJ1ZyM1NjY3NDogW1NoZXBoZXJkXSBVc2Ugb2Yg4oCYd2FpdHBp?= =?UTF-8?B?ZOKAmSwg4oCYc3lzdGVtKuKAmSwgZXRjLiBpbiBzZXJ2aWNlIGNvZGUgY2FuIGNh?= =?UTF-8?Q?use_deadlocks?= References: <8735evpipv.fsf@inria.fr> <87fsiujwzo.fsf@gnu.org> In-Reply-To: <87fsiujwzo.fsf@gnu.org> --------------CWlN6Dx403tuLcg6YEJPHBn2 Content-Type: multipart/mixed; boundary="------------OGyN1Qa7DXmUwPCbmSdGJxTl" --------------OGyN1Qa7DXmUwPCbmSdGJxTl Content-Type: multipart/alternative; boundary="------------zKqmxUGRaK7cHHQjLa0snekO" --------------zKqmxUGRaK7cHHQjLa0snekO Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: base64 DQpPbiAyMS0wNy0yMDIyIDE3OjM5LCBMdWRvdmljIENvdXJ0w6hzIHdyb3RlOg0KPj4gQWx0 ZXJuYXRpdmVseToNCj4+DQo+PiA0LiBEbyB0aGUgd2FpdHBpZCBpbiBhIHNlcGFyYXRlIHRo cmVhZCAobmVlZHMgd29yay1hcm91bmQgZm9yIHRoZQ0KPj4gbXVsdGktdGhyZWFkZWQgZm9y ayBwcm9ibGVtLCBwcm9iYWJseSBDIHRoaW5ncz8gT3IgbW9kaWZ5aW5nIEd1aWxlIGFuZA0K Pj4gbWF5YmUgZ2xpYmMgdG8gYXZvaWQgYXN5bmMtdW5zYWZlIHRoaW5ncyBvciBtYWtlIG1v cmUgdGhpbmdzDQo+PiBhc3luYy1zYWZlIG9yIHdoYXRldmVyIHRoZSBhcHByb3ByaWF0ZSAu Li4tc2FmZSBpcyBoZXJlLikNCj4gRm9yIHNoZXBoZXJkLCBtdWx0aXRocmVhZGluZyBpcyBu b3QgYW4gb3B0aW9uIGR1ZSB0byB0aGUgc2VtYW50aWNzIG9mDQo+IGZvcmsgaW4gdGhlIHBy ZXNlbmNlIG9mIHRocmVhZHMuDQoNCiBGcm9tIHdoYXQgSSd2ZSByZWFkLCBtdWx0aS10aHJl YWRlZCBmb3JrIGlzIHNhZmUgYXMgbG9uZyBhcyB5b3UgZG8gYW4gDQpleGVjICdpbW1lZGlh dGVseScgYWZ0ZXJ3YXJkcywgd2l0aG91dCBkb2luZyB0aGluZ3MgbGlrZSB0YWtpbmcgbG9j a3Mgb3IgDQphbGxvY2F0aW5nIG1lbW9yeSB3aXRoIG1hbGxvYyBpbi1iZXR3ZWVuIHRoZSBm b3JrIGFuZCBleGVjLiBJIGRvbid0IA0KdGhpbmsgaXQncyBwb3NzaWJsZSB0byBkbyB0aGF0 IGluIEd1aWxlIGNvZGUsIGJ1dCB0aGF0J3Mgd2hhdCB0aGUgQyANCnRoaW5ncyBhcmUgZm9y Lg0KDQpHcmVldGluZ3MsDQpNYXhpbWUuDQo= --------------zKqmxUGRaK7cHHQjLa0snekO Content-Type: text/html; 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On 21-07-2022 17:39, Ludovic Court=C3=A8= s wrote:
Alternatively:

4. Do the waitpid in a separate thread (needs work-around for the
multi-threaded fork problem, probably C things? Or modifying Guile and
maybe glibc to avoid async-unsafe things or make more things
async-safe or whatever the appropriate ...-safe is here.)

For shepherd, multithreading=
 is not an option due to the semantics of
fork in the presence of threads.

From what I've read, multi-threaded fork is safe as long as you do an exec 'immediately' afterwards, without doing things like taking locks or allocating memory with malloc in-between the fork and exec. I don't think it's possible to do that in Guile code, but that's what the C things are for.

Greetings,
Maxime.
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