DOC: unreliable sockpair@ on macOS

We discovered that the sockpair@ protocol is unreliable in macOS, this
is the same problem that we fixed in d7f6819. But it's not possible to
implement a acknowledgment once the socket are in non-blocking mode.

The problem was discovered in issue #3045.

Must be backported in every stable versions.

(cherry picked from commit 8a456399dba70c9880394a7e85f9523feb1505c5)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 0746af209c3600a908b141f213c8ba7bb807840a)
[cf: ctx adjt]
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 16ab3761721b11803d6b5df38a487a8bf48a8b49)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/doc/configuration.txt b/doc/configuration.txt
index d09e003..a3429cb 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -28227,6 +28227,10 @@ socket type and the transport method.
                the FD from the unix socket and uses it as if it were the FD
                of an accept(). Should be used carefully.
 
+               Bugs: This protocol is known to be unreliable on macOS because
+               of an issue in the macOS sendmsg(2) implementation. The
+               connection might not be accepted correctly.
+
 'unix@<path>'  following string is considered as a UNIX socket <path>. this
                prefix is useful to declare an UNIX socket path which don't
                start by slash '/'.

diff --git a/doc/management.txt b/doc/management.txt
index 713eb06..ee9bed3 100644 (file)
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -4178,6 +4178,11 @@ Example:
   master. Leaving processes are only accessible with the PID as relative process
   number are only usable with the current processes.
 
+  Bugs: the sockpair@ protocol used to implement communication between the
+  master and the worker is known to not be reliable on macOS because of an
+  issue in the macOS sendmsg(2) implementation. A command might end up without
+  response because of that.
+
   Examples:
 
     $ socat /var/run/haproxy-master.sock readline