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Message-ID: <ed72aa98-151a-0f1b-062b-fbea08b38f6f@suse.cz>
Date:   Mon, 16 Jan 2023 11:45:33 +0100
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From:   =?UTF-8?Q?Martin_Li=c5=a1ka?= <mliska@suse.cz>
Subject: [PATCH] scripts: support GNU make 4.4 in jobserver-exec
To:     linux-kernel@vger.kernel.org
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Cc:     linux-block@vger.kernel.org,
        Masahiro Yamada <masahiroy@kernel.org>, nicolas@fjasle.eu,
        axboe@kernel.dk, josef@toxicpanda.com, keescook@chromium.org
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Starting with GNU make 4.4, --jobserver-auth newly uses named
pipe (fifo) instead of part of opened file descriptors:
https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html

Support also the new format.

Signed-off-by: Martin Liska <mliska@suse.cz>
---
 scripts/jobserver-exec | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/scripts/jobserver-exec b/scripts/jobserver-exec
index 4192855f5b8b..7eca035472d3 100755
--- a/scripts/jobserver-exec
+++ b/scripts/jobserver-exec
@@ -26,11 +26,20 @@ try:
 	# If the MAKEFLAGS variable contains multiple instances of the
 	# --jobserver-auth= option, the last one is relevant.
 	fds = opts[-1].split("=", 1)[1]
-	reader, writer = [int(x) for x in fds.split(",", 1)]
-	# Open a private copy of reader to avoid setting nonblocking
-	# on an unexpecting process with the same reader fd.
-	reader = os.open("/proc/self/fd/%d" % (reader),
-			 os.O_RDONLY | os.O_NONBLOCK)
+
+	# Starting with GNU Make 4.4, named pipes are used for reader and writer.
+	# Example argument: --jobserver-auth=fifo:/tmp/GMfifo8134
+	_, _, path = fds.partition('fifo:')
+
+	if path:
+		reader = os.open(path, os.O_RDONLY | os.O_NONBLOCK)
+		writer = os.open(path, os.O_WRONLY)
+	else:
+		reader, writer = [int(x) for x in fds.split(",", 1)]
+		# Open a private copy of reader to avoid setting nonblocking
+		# on an unexpecting process with the same reader fd.
+		reader = os.open("/proc/self/fd/%d" % (reader),
+				 os.O_RDONLY | os.O_NONBLOCK)
 
 	# Read out as many jobserver slots as possible.
 	while True:
-- 
2.39.0