[PATCH] trace2: intercept all common signals
- From
Emily Shaffer <emilyshaffer@google.com>
- Date
- May 10, 2024, 17:22 UTC
- Message-ID
- <20240510172243.3529851-1-emilyshaffer@google.com>
From: Emily Shaffer <nasamuffin@google.com>
We already use trace2 to find out about unexpected pipe breakages, which is nice for detecting bugs or system problems, by adding a handler for SIGPIPE which simply writes a trace2 line. However, there are a handful of other common signals which we might want to snoop on:
- SIGINT, SIGTERM, or SIGQUIT, when a user manually cancels a command in frustration or mistake (via Ctrl-C, Ctrl-D, or `kill`) - SIGHUP, when the network closes unexpectedly (indicating there may be a problem to solve)
There are lots more signals which we might find useful later, but at least let's teach trace2 to report these egregious ones. Conveniently, they're also already covered by the `_common` variants in sigchain.[ch].
Sigchain itself is already tested via helper/test-sigchain.c, and trace2 is tested in a number of places - let's also add tests demonstrating that sigchain + trace2 works correctly.
Signed-off-by: Emily Shaffer <nasamuffin@google.com> --- t/helper/test-trace2.c | 17 +++++++++++++++++ t/t0210-trace2-normal.sh | 22 ++++++++++++++++++++++ trace2.c | 2 +- 3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/t/helper/test-trace2.c b/t/helper/test-trace2.c index 1adac29a57..8970956ea8 100644 --- a/t/helper/test-trace2.c +++ b/t/helper/test-trace2.c @@ -231,6 +231,22 @@ static int ut_010bug_BUG(int argc UNUSED, const char **argv UNUSED) BUG("a %s message", "BUG"); } +static int ut_011signal(int argc, const char **argv) +{ + const char *usage_error = "expect <bool common>"; + int common = 0; + + if (argc != 1 || get_i(&common, argv[0])) + die("%s", usage_error); + + /* + * There is no strong reason SIGSEGV is ignored by trace2 - it's just + * not included by sigchain_push_common(). + */ + raise(common ? SIGINT : SIGSEGV); + return 0; /*unreachable*/ +} + /* * Single-threaded timer test. Create several intervals using the * TEST1 timer. The test script can verify that an aggregate Trace2 @@ -482,6 +498,7 @@ static struct unit_test ut_table[] = { { ut_008bug, "008bug", "" }, { ut_009bug_BUG, "009bug_BUG","" }, { ut_010bug_BUG, "010bug_BUG","" }, + { ut_011signal, "011signal","" }, { ut_100timer, "100timer", "<count> <ms_delay>" }, { ut_101timer, "101timer", "<count> <ms_delay> <threads>" }, diff --git a/t/t0210-trace2-normal.sh b/t/t0210-trace2-normal.sh index c312657a12..c34ccc518c 100755 --- a/t/t0210-trace2-normal.sh +++ b/t/t0210-trace2-normal.sh @@ -244,6 +244,28 @@ test_expect_success 'bug messages followed by BUG() are written to trace2' ' test_cmp expect actual ' +test_expect_success 'trace2 reports common signals' ' + test_when_finished "rm trace.normal actual" && + + # signals are fatal, so expect this to fail + ! env GIT_TRACE2="$(pwd)/trace.normal" test-tool trace2 011signal 1 && + + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <trace.normal >actual && + + test_grep "signal elapsed:" actual +' + +test_expect_success 'trace2 ignores uncommon signals' ' + test_when_finished "rm trace.normal actual" && + + # signals are fatal, so expect this to fail + ! env GIT_TRACE2="$(pwd)/trace.normal" test-tool trace2 011signal 0 && + + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <trace.normal >actual && + + ! test_grep "signal elapsed:" actual +' + sane_unset GIT_TRACE2_BRIEF # Now test without environment variables and get all Trace2 settings diff --git a/trace2.c b/trace2.c index f894532d05..3692010f5d 100644 --- a/trace2.c +++ b/trace2.c @@ -231,7 +231,7 @@ void trace2_initialize_fl(const char *file, int line) tr2_sid_get(); atexit(tr2main_atexit_handler); - sigchain_push(SIGPIPE, tr2main_signal_handler); + sigchain_push_common(tr2main_signal_handler); tr2tls_init(); /*
-- 2.45.0.118.g7fe29c98d7-goog