From: Olivier Houchard <ohouchard@haproxy.com>
Date: Thu, 30 Jul 2026 12:03:55 +0000 (+0200)
Subject: BUILD: listener: Fix the build on platforms without MSG_CMSG_CLOEXEC
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=9afec06e0eb477e29b7eeaf9eb8b5039ca4a470a;p=thirdparty%2Fhaproxy.git

BUILD: listener: Fix the build on platforms without MSG_CMSG_CLOEXEC

Some OSes, such as macos, do not provide MSG_CMSG_CLOEXEC, so provide a
fallback mechanism using fdcntl(FD_CLOEXEC) instead.
It doesn't matter right now, that code will never be used on such OS,
because you can't use per-thread-group fd tables in there, but maybe it
will change one day.
---

diff --git a/include/haproxy/compat.h b/include/haproxy/compat.h
index 39f7af7a6..3f0f0b393 100644
--- a/include/haproxy/compat.h
+++ b/include/haproxy/compat.h
@@ -150,6 +150,14 @@ typedef struct { } empty_t;
 #define MSG_DONTWAIT	0
 #endif
 
+/*
+ * Not every OS defines MSG_CMSG_CLOEXEC, so get a fallback version, to
+ * be tested when using it.
+ */
+#ifndef MSG_CMSG_CLOEXEC
+#define MSG_CMSG_CLOEXEC	0
+#endif
+
 /* Only Linux defines MSG_MORE */
 #ifndef MSG_MORE
 #define MSG_MORE	0
diff --git a/src/listener.c b/src/listener.c
index 29a938090..7018b08b0 100644
--- a/src/listener.c
+++ b/src/listener.c
@@ -14,6 +14,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <fcntl.h>
 #include <unistd.h>
 
 #include <import/ist.h>
@@ -969,6 +970,10 @@ void rx_xfer_drain(uint grp)
 		if (cmsg && cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
 			memcpy(&fd, CMSG_DATA(cmsg), sizeof(int));
 
+		/* platforms with no MSG_CMSG_CLOEXEC get it set by hand */
+		if (!MSG_CMSG_CLOEXEC && fd >= 0)
+			fcntl(fd, F_SETFD, FD_CLOEXEC);
+
 		if (ret != sizeof(xmsg) || fd < 0) {
 			if (fd >= 0)
 				close(fd);