Subject: [PATCH] store: Use a non-blocking socket for store connections.
From: Christopher Baines <[email-masked]>
To: [email-masked]
Date: Fri, 17 Nov 2023 18:05:14 +0000
List-Id: <debbugs-submit.debbugs.gnu.org>

For some applications, it's important to do this here rather than just making
the socket non-blocking after the connection is established because there can
be I/O on the socket that will block during the handshake.

I've noticed this blocking during the handshake causing issues in the build
coordinator for example.

* guix/store.scm (open-unix-domain-socket, open-inet-socket): Pass
SOCK_NONBLOCK when calling socket.

Change-Id: I8225762b78448bc1f7b698c8de5d736e13f577bf
---
 guix/store.scm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/guix/store.scm b/guix/store.scm
index f8e77b2cd9..216be98c05 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -460,7 +460,9 @@ (define (open-unix-domain-socket file)
 '&store-connection-error' upon error."
   (let ((s (with-fluids ((%default-port-encoding #f))
              ;; This trick allows use of the `scm_c_read' optimization.
-             (socket PF_UNIX (logior SOCK_STREAM SOCK_CLOEXEC) 0)))
+             (socket PF_UNIX
+                     (logior SOCK_STREAM SOCK_CLOEXEC SOCK_NONBLOCK)
+                     0)))
         (a (make-socket-address PF_UNIX file)))
 
     (system-error-to-connection-error file
@@ -488,7 +490,8 @@ (define (open-inet-socket host port)
       ((ai rest ...)
        (let ((s (socket (addrinfo:fam ai)
                         ;; TCP/IP only
-                        (logior SOCK_STREAM SOCK_CLOEXEC) IPPROTO_IP)))
+                        (logior SOCK_STREAM SOCK_CLOEXEC SOCK_NONBLOCK)
+                        IPPROTO_IP)))
 
          (catch 'system-error
            (lambda ()

base-commit: e35b7c5386c1bfacf47ed31bac9b503373dd26fc
-- 
2.41.0