commit: 077e60fb9c46247fc053df29b9416b46c90ae6c7 Author: Michael Haubenwallner <michael.haubenwallner <AT> ssi-schaefer <DOT> com> AuthorDate: Wed Apr 27 15:21:52 2016 +0000 Commit: Michael Haubenwallner <haubi <AT> gentoo <DOT> org> CommitDate: Mon Jan 16 10:00:38 2017 +0000 URL: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=077e60fb
multiprocessing.eclass: 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 eclass/multiprocessing.eclass | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/eclass/multiprocessing.eclass b/eclass/multiprocessing.eclass index 70ca475..67f7e2d 100644 --- a/eclass/multiprocessing.eclass +++ b/eclass/multiprocessing.eclass @@ -139,11 +139,16 @@ 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="${T}/multijob.pipe" mkfifo -m 600 "${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.
