commit: 5a53e732efa0ee7e2a3f8afe90d729212ff187fb Author: Michael Haubenwallner <haubi <AT> gentoo <DOT> org> AuthorDate: Tue May 24 10:54:38 2016 +0000 Commit: Zac Medico <zmedico <AT> gentoo <DOT> org> CommitDate: Sat Jan 14 00:13:42 2017 +0000 URL: https://gitweb.gentoo.org/proj/portage.git/commit/?id=5a53e732
__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 c096aed..9b6e201 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.
