From 5a53e732efa0ee7e2a3f8afe90d729212ff187fb Mon Sep 17 00:00:00 2001 From: Michael Haubenwallner Date: Tue, 24 May 2016 12:54:38 +0200 Subject: __multijob_init: work around Cygwin FIFO shortcoming Cygwin does not support multiple read-handles for one FIFO (yet). As we really need just one readonly- and one writeonly-handle, we can reorder to open one single readwrite- and one writeonly-handle. X-Gentoo-Bug: 583962 X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=583962 --- bin/helper-functions.sh | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/bin/helper-functions.sh b/bin/helper-functions.sh index c096aedb6..9b6e201aa 100644 --- a/bin/helper-functions.sh +++ b/bin/helper-functions.sh @@ -20,12 +20,17 @@ makeopts_jobs() { __multijob_init() { # Setup a pipe for children to write their pids to when they finish. # We have to allocate two fd's because POSIX has undefined behavior - # when you open a FIFO for simultaneous read/write. #487056 + # when using one single fd for both read and write. #487056 + # However, opening an fd for read or write only will block until the + # opposite end is opened as well. Thus we open the first fd for both + # read and write to not block ourselve, but use it for reading only. + # The second fd really is opened for write only, as Cygwin supports + # just one single read fd per FIFO. #583962 local pipe=$(mktemp -t multijob.XXXXXX) rm -f "${pipe}" mkfifo -m 600 "${pipe}" - __redirect_alloc_fd mj_write_fd "${pipe}" __redirect_alloc_fd mj_read_fd "${pipe}" + __redirect_alloc_fd mj_write_fd "${pipe}" '>' rm -f "${pipe}" # See how many children we can fork based on the user's settings. -- cgit v1.2.3-65-gdbad