+2008-11-23 Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
+
+ More reliable signal handling in Autotest.
+ * lib/autotest/general.m4 (Driver loop): Rewrite signal handler.
+ Start parallel jobs in their own process group, enabling job
+ control in the shell if possible, for better signal handling.
+ Deal with INT, TERM, and HUP in the testsuite driver. In the
+ parallel driver, propagate TSTP to jobs either as TSTP or as
+ STOP (to avoid fork bombs with ksh).
+ Inside the job processes, add PIPE handler to write back the
+ job token, so the master process does not hang.
+ Disable the parallel driver if job control is not provided or if
+ trap does not understand signal names.
+ * tests/autotest.at (parallel autotest and signals): New test,
+ exercises INT, TERM, and PIPE, serial and parallel, with and
+ without `make' in the loop.
+ Kudos to Richard Stevens for writing APUE.
+
2008-11-22 Eric Blake <ebb9@byu.net>
Fix testsuite failure on Solaris.
m4_text_box([Driver loop.])
+dnl Catching signals correctly:
+dnl
+dnl The first idea was: trap the signal, send it to all spawned jobs,
+dnl then reset the handler and reraise the signal for ourselves.
+dnl However, before exiting, ksh will then send the signal to all
+dnl process group members, potentially killing the outer testsuite
+dnl and/or the 'make' process driving us.
+dnl So now the strategy is: trap the signal, send it to all spawned jobs,
+dnl then exit the script with the right status.
+dnl
+dnl In order to let the jobs know about the signal, we cannot just send it
+dnl to the current process group (kill $SIG 0), for the same reason as above.
+dnl Also, it does not reliably stop the suite to send the signal to the
+dnl spawned processes, because they might not transport it further
+dnl (maybe this can be fixed?).
+dnl
+dnl So what we do is enable shell job control if available, which causes the
+dnl shell to start each parallel task as its own shell job, thus as a new
+dnl process group leader. We then send the signal to all new process groups.
+
+dnl Do we have job control?
+if (set -m && set +m) >/dev/null 2>&1; then
+ at_job_control_on='set -m' at_job_control_off='set +m' at_job_group=-
+else
+ at_job_control_on=: at_job_control_off=: at_job_group=
+fi
+
+for at_signal in 1 2 15; do
+dnl This signal handler is not suitable for PIPE: it causes writes.
+dnl The code that was interrupted may have the errexit, monitor, or xtrace
+dnl flags enabled, so sanitize.
+ trap 'set +x; set +e
+ $at_job_control_off
+ at_signal='"$at_signal"'
+dnl Safety belt: even with runaway processes, prevent starting new jobs.
+ echo stop > "$at_stop_file"
+dnl Do not enter this area multiple times, do not kill self prematurely.
+ trap "" $at_signal
+dnl Gather process group IDs of currently running jobs.
+ at_pgids=
+ for at_pgid in `jobs -p 2>/dev/null`; do
+ at_pgids="$at_pgids $at_job_group$at_pgid"
+ done
+dnl Ignore `kill' errors, as some jobs may have finished in the meantime.
+ test -z "$at_pgids" || kill -$at_signal $at_pgids 2>/dev/null
+dnl wait until all jobs have exited.
+ wait
+dnl Status output. Do this after waiting for the jobs, for ordered output.
+dnl Avoid scribbling onto the end of a possibly incomplete line.
+ if test "$at_jobs" -eq 1 || test -z "$at_verbose"; then
+ echo >&2
+ fi
+ at_signame=`kill -l $at_signal 2>&1 || echo $at_signal`
+ set x $at_signame
+ test $# -gt 2 && at_signame=$at_signal
+ AS_WARN([caught signal $at_signame, bailing out])
+dnl Do not reinstall the default handler here and reraise the signal to
+dnl let the default handler do its job, see the note about ksh above.
+dnl trap - $at_signal
+dnl kill -$at_signal $$
+dnl Instead, exit with appropriate status.
+ AS_VAR_ARITH([exit_status], [128 + $at_signal])
+ AS_EXIT([$exit_status])' $at_signal
+done
+
rm -f "$at_stop_file"
-trap 'exit_status=$?
- echo "signal received, bailing out" >&2
- echo stop > "$at_stop_file"
- exit $exit_status' 1 2 13 15
at_first=:
if test $at_jobs -ne 1 &&
rm -f "$at_job_fifo" &&
- ( mkfifo "$at_job_fifo" ) 2>/dev/null &&
+ test -n "$at_job_group" &&
+ ( mkfifo "$at_job_fifo" && trap 'exit 1' PIPE STOP TSTP ) 2>/dev/null &&
exec AT_JOB_FIFO_FD<> "$at_job_fifo"
then
# FIFO job dispatcher.
+
+dnl Since we use job control, we need to propagate TSTP.
+dnl This handler need not be used for serial execution.
+dnl Again, we should stop all processes in the job groups, otherwise
+dnl the stopping will not be effective while one test group is running.
+dnl Apparently ksh does not honor the TSTP trap.
+dnl As a safety measure, not use the same variable names as in the
+dnl termination handlers above, one might get called during execution
+dnl of the other.
+ trap 'at_pids=
+ for at_pid in `jobs -p`; do
+ at_pids="$at_pids $at_job_group$at_pid"
+ done
+dnl Send it to all spawned jobs, ignoring those finished meanwhile.
+ if test -n "$at_pids"; then
+dnl Unfortunately, ksh93 fork-bombs when we send TSTP, so send STOP
+dnl if this might be ksh (STOP prevents possible TSTP handlers inside
+dnl AT_CHECKs from running). Then stop ourselves.
+ at_sig=TSTP
+ test "${TMOUT+set}" = set && at_sig=STOP
+ kill -$at_sig $at_pids 2>/dev/null
+ fi
+ kill -STOP $$
+dnl We got a CONT, so let's go again. Passing this to all processes
+dnl in the groups is necessary (because we stopped them), but it may
+dnl cause changed test semantics; e.g., a sleep will be interrupted.
+ test -z "$at_pids" || kill -CONT $at_pids 2>/dev/null' TSTP
+
echo
# Turn jobs into a list of numbers, starting from 1.
at_joblist=`AS_ECHO([" $at_groups_all "]) | \
set X $at_joblist
shift
for at_group in $at_groups; do
+dnl Enable job control only for spawning the test group:
+dnl Let the jobs to run in separate process groups, but
+dnl avoid all the status output by the shell.
+ $at_job_control_on
(
# Start one test group.
+ $at_job_control_off
+dnl When a child receives PIPE, be sure to write back the token,
+dnl so the master does not hang waiting for it.
+dnl errexit and xtrace should not be set in this shell instance,
+dnl except as debug measures. However, shells such as dash may
+dnl optimize away the _AT_CHECK subshell, so normalize here.
+ trap 'set +x; set +e
+dnl Ignore PIPE signals that stem from writing back the token.
+ trap "" PIPE
+ echo stop > "$at_stop_file"
+ echo token >&6
+dnl Do not reraise the default PIPE handler.
+dnl It wreaks havoc with ksh, see above.
+dnl trap - 13
+dnl kill -13 $$
+ AS_EXIT([141])' PIPE
at_fn_group_prepare
if cd "$at_group_dir" &&
at_fn_test $at_group &&
at_fn_group_postprocess
echo token >&AT_JOB_FIFO_FD
) &
+ $at_job_control_off
shift # Consume one token.
if test $[@%:@] -gt 0; then :; else
read at_token <&AT_JOB_FIFO_FD || break
[-j2 --errexit])
+AT_SETUP([parallel autotest and signal handling])
+
+# Goals:
+# (1) interrupt `./testsuite -jN'
+# (2) interrupt `make check TESTSUITEFLAGS=-jN'
+# (3) no trailing verbose/trace output
+# (4) exit status should be 128+signal
+
+AT_DATA([atlocal],
+[[suite_pid=$$
+export suite_pid
+]])
+
+AT_CHECK_AT_PREP([micro-suite],
+[[AT_INIT([suite to test parallel execution])
+AT_SETUP([test number 1])
+AT_CHECK([sleep 2])
+AT_CLEANUP
+AT_SETUP([test number 2])
+AT_CHECK([sleep 1])
+AT_CLEANUP
+AT_SETUP([test number 3])
+AT_CHECK([sleep 1])
+AT_CLEANUP
+AT_SETUP([killer test])
+AT_CHECK([kill -$signal $suite_pid])
+AT_CLEANUP
+m4_for([count], [5], [7], [],
+ [AT_SETUP([test number count])
+ AT_CHECK([sleep 1])
+ AT_CLEANUP
+])
+]])
+
+AT_DATA([Makefile.in],
+[[@SET_MAKE@
+SHELL = @SHELL@
+TESTSUITE = ./micro-suite
+check:
+ $(SHELL) '$(TESTSUITE)' $(TESTSUITEFLAGS)
+.PHONY: check
+]])
+
+AT_CHECK([$CONFIG_SHELL $abs_top_builddir/config.status --file=Makefile:Makefile.in],
+ [], [ignore])
+
+# Test INT and TERM.
+for signal in 2 15; do
+ export signal
+ AS_VAR_ARITH([expected_status], [128 + $signal])
+
+ # Sequential case.
+ AT_CHECK([$CONFIG_SHELL ./micro-suite], [$expected_status],
+ [ignore], [stderr])
+ # Both stderr and the log should contain the notification about the signal.
+ AT_CHECK([grep 'bailing out' stderr], [], [ignore])
+ AT_CHECK([grep 'bailing out' micro-suite.log], [], [ignore])
+ # There should be no junk job status output.
+ AT_CHECK([[grep '[iI]nterrupt[ ]' stderr]], [1])
+
+ # Parallel case.
+ AT_CHECK([$CONFIG_SHELL ./micro-suite --jobs=3], [$expected_status],
+ [ignore], [stderr])
+ AT_CHECK([grep 'bailing out' stderr], [], [ignore])
+ AT_CHECK([grep 'bailing out' micro-suite.log], [], [ignore])
+ # We'd like to check this here, too, but some shells do not allow to
+ # turn off job control.
+ # AT_CHECK([[grep '[iI]nterrupt[ ]' stderr]], [1])
+
+ # Ditto with `make' in the loop.
+ : ${MAKE=make}
+ unset MAKEFLAGS
+ # Need to eliminate outer TESTSUITEFLAGS here.
+ # Need to normalize exit status here: some make implementations
+ # exit 1 (BSD make), some exit 2 (GNU make).
+ AT_CHECK([$MAKE check TESTSUITEFLAGS=; ]dnl
+ [case $? in 1|2) exit 1;; *) exit $?;; esac],
+ [1], [ignore], [stderr])
+ AT_CHECK([grep 'bailing out' stderr], [], [ignore])
+ AT_CHECK([grep 'bailing out' micro-suite.log], [], [ignore])
+ # Ditto, parallel case.
+ AT_CHECK([$MAKE check TESTSUITEFLAGS=--jobs=3; ]dnl
+ [case $? in 1|2) exit 1;; *) exit $?;; esac],
+ [1], [ignore], [stderr])
+ AT_CHECK([grep 'bailing out' stderr], [], [ignore])
+ AT_CHECK([grep 'bailing out' micro-suite.log], [], [ignore])
+done
+
+
+# Test PIPE.
+# The most important part here is that things should not hang, nor
+# get out of hand. OTOH, if the shell sets the default handler to
+# ignore PIPE (pdksh, dash), there is little we can do about having the
+# test run; it's only the output that won't be there. So all we check
+# for is that, if test 7 didn't run serially, then it shouldn't be
+# run in the parallel case either; the intermediate tests serve as
+# parallel barrier.
+# Note that stderr may contain "Broken pipe" errors.
+AT_CHECK([($CONFIG_SHELL ./micro-suite -d -3 5-; echo $? >status) | sed 5q],
+ [], [stdout], [stderr])
+AT_CHECK([grep '5.*ok' stdout], [1])
+# Apparently some shells don't get around to creating 'status' any more.
+# And ksh93 on FreeBSD uses 256 + 13 instead of 128 + 13
+AT_CHECK([test ! -s status || grep 141 status || grep 269 status],
+ [], [ignore])
+AT_CHECK([if test -f micro-suite.dir/7/micro-suite.log; then ]dnl
+ [ echo "shell ignores SIGPIPE" > sigpipe-stamp ]dnl
+ [else :; fi])
+
+AT_CHECK([$CONFIG_SHELL ./micro-suite -d -3 5- --jobs=2 | sed 5q], [], [stdout], [ignore])
+AT_CHECK([grep '5.*ok' stdout], [1])
+AT_CHECK([test -s sigpipe-stamp || test ! -f micro-suite.dir/7/micro-suite.log], [0])
+
+AT_CLEANUP
+
## ------------------- ##
## srcdir propagation. ##
## ------------------- ##
projects / thirdparty / autoconf.git / commitdiff
