[Xen-devel] [OSSTEST PATCH 02/11] cri-getconfig: Break out exec_resetting_sigint.

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

Move this oddity (and the associated comment) from
standalone-generate-dump-flight-runvars to cri-getconfig.  We are
going to want it elsewhere.

We put this in cri-getconfig because that is the one library of
generic shell functions which everything includes.  Perhaps this file
is misnamed.

No overall functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
---
 cri-getconfig                           |   30 ++++++++++++++++++++++++++++++
 standalone-generate-dump-flight-runvars |   28 +---------------------------
 2 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/cri-getconfig b/cri-getconfig
index 0589bf0..ee1cc40 100644
--- a/cri-getconfig
+++ b/cri-getconfig
@@ -39,3 +39,33 @@ getrepos() {
        fi
        echo $repos
 }
+
+# Good grief, handling background proceesses from shell is a pain.
+#
+# For stupid historical reasons, background processes start with
+# SIGINT (and QUIT) ignored (SuSv3 2.11).  bash does not currently
+# offer a way to ask it not to do this; nor is there a reliable way to
+# put the SIGINT handling back to normal.
+#
+# "trap - INT" can be used to put the handling back in recent versions
+# of bash (eg Debian jessie), but earlier versions are buggy, so
+# we use perl.
+#
+# However, there is still a race: if the signal arrives just after the
+# fork, after the shell has (in the child) set it to to IGN, but
+# before Perl has put it back, the child might still escape.
+# There is no reasonable way to deal with this race.  So the result
+# may still be slightly racy in the case that s-g-d-f-r is ^C'd right
+# after starting.
+#
+# Hopefully in the future we can fix this with something like
+# "shopt -s no_async_sig_ignore".  See
+# https://lists.gnu.org/archive/html/bug-bash/2015-10/msg00077.html
+#
+exec_resetting_sigint () {
+       exec perl -e '
+               $SIG{$_}=DFL foreach qw(INT QUIT HUP);
+               kill 1, $$ unless getppid=='$$';
+               exec @ARGV or die $!;
+       ' "$@"
+}
diff --git a/standalone-generate-dump-flight-runvars 
b/standalone-generate-dump-flight-runvars
index e91026a..3b20c62 100755
--- a/standalone-generate-dump-flight-runvars
+++ b/standalone-generate-dump-flight-runvars
@@ -58,35 +58,9 @@ perbranch () {
     flight=check_${branch//[-._]/_}
 }
 
-# Good grief, handling background proceesses from shell is a pain.
-#
-# For stupid historical reasons, background processes start with
-# SIGINT (and QUIT) ignored (SuSv3 2.11).  bash does not currently
-# offer a way to ask it not to do this; nor is there a reliable way to
-# put the SIGINT handling back to normal.
-#
-# "trap - INT" can be used to put the handling back in recent versions
-# of bash (eg Debian jessie), but earlier versions are buggy, so
-# we use perl.
-#
-# However, there is still a race: if the signal arrives just after the
-# fork, after the shell has (in the child) set it to to IGN, but
-# before Perl has put it back, the child might still escape.
-# There is no reasonable way to deal with this race.  So the result
-# may still be slightly racy in the case that s-g-d-f-r is ^C'd right
-# after starting.
-#
-# Hopefully in the future we can fix this with something like
-# "shopt -s no_async_sig_ignore".  See
-# https://lists.gnu.org/archive/html/bug-bash/2015-10/msg00077.html
-
 for branch in $@; do
     perbranch
-    perl -e '
-        $SIG{$_}=DFL foreach qw(INT QUIT HUP);
-       kill 1, $$ unless getppid=='$$';
-       exec @ARGV or die $!;
-    ' \
+    exec_resetting_sigint \
     ./standalone make-flight -f $flight $branch >$log 2>&1 &
     procs+=" $branch=$!"
 done
-- 
1.7.10.4


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