From 97ca0712c8f2b65479649693ffe01e7358418955 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Tue, 3 Jul 2018 10:53:31 +0200 Subject: [PATCH] qmp: Get rid of x-oob-test command tests/qmp-test tests an out-of-band command overtaking a slow in-band command. To do that, it needs: 1. An in-band command that *reliably* takes long enough to be overtaken. 2. An out-of-band command to do the overtaking. 3. To avoid delays, a way to make the in-band command complete quickly after it was overtaken. To satisfy these needs, commit 469638f9cb3 provides the rather peculiar oob-capable QMP command x-oob-test: * With "lock": true, it waits for a global semaphore. * With "lock": false, it signals the global semaphore. To satisfy 1., the test runs x-oob-test in-band with "lock": true. To satisfy 2. and 3., it runs x-oob-test out-of-band with "lock": false. Note that waiting for a semaphore violates the rules for oob-capable commands. Running x-oob-test with "lock": true hangs the monitor until you run x-oob-test with "lock": false on another monitor (which you might not have set up). Having an externally visible QMP command that may hang the monitor is not nice. Let's apply a little more ingenuity to the problem. Idea: have an existing command block on reading a FIFO special file, unblock it by opening the FIFO for writing. For 1., use {"execute": "blockdev-add", "id": ID1, "arguments": { "driver": "blkdebug", "node-name": ID1, "config": FIFO, "image": { "driver": "null-co"}}} where ID1 is an arbitrary string, and FIFO is the name of the FIFO. For 2., use {"execute": "migrate-pause", "id": ID2, "control": {"run-oob": true}} where ID2 is a different arbitrary string. Since there's no migration to pause, the command will fail, but that's fine; instant failure is still a test of out-of-band responses overtaking in-band commands. For 3., open FIFO for writing. Drop QMP command x-oob-test. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <20180703085358.13941-6-armbru@redhat.com> [Error checking tweaked] --- qapi/misc.json | 18 ----------- qmp.c | 16 ---------- tests/qmp-test.c | 95 ++++++++++++++++++++++++++++++++++++++------------------ 3 files changed, 65 insertions(+), 64 deletions(-) diff --git a/qapi/misc.json b/qapi/misc.json index 74cd97f237..f1860418e8 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -3473,24 +3473,6 @@ 'data': { 'id': 'any', 'reason': 'CommandDropReason' } } ## -# @x-oob-test: -# -# Test OOB functionality. When sending this command with lock=true, -# it'll try to hang the dispatcher. When sending it with lock=false, -# it'll try to notify the locked thread to continue. Note: it should -# only be used by QMP test program rather than anything else. -# -# Since: 2.12 -# -# Example: -# -# { "execute": "x-oob-test", -# "arguments": { "lock": true } } -## -{ 'command': 'x-oob-test', 'data' : { 'lock': 'bool' }, - 'allow-oob': true } - -## # @set-numa-node: # # Runtime equivalent of '-numa' CLI option, available at diff --git a/qmp.c b/qmp.c index 73e46d795f..62325ac6aa 100644 --- a/qmp.c +++ b/qmp.c @@ -775,19 +775,3 @@ MemoryInfo *qmp_query_memory_size_summary(Error **errp) return mem_info; } - -static QemuSemaphore x_oob_test_sem; - -static void __attribute__((constructor)) x_oob_test_init(void) -{ - qemu_sem_init(&x_oob_test_sem, 0); -} - -void qmp_x_oob_test(bool lock, Error **errp) -{ - if (lock) { - qemu_sem_wait(&x_oob_test_sem); - } else { - qemu_sem_post(&x_oob_test_sem); - } -} diff --git a/tests/qmp-test.c b/tests/qmp-test.c index 5206b14ca6..467b694aa2 100644 --- a/tests/qmp-test.c +++ b/tests/qmp-test.c @@ -135,16 +135,66 @@ static void test_qmp_protocol(void) qtest_quit(qts); } -/* Tests for out-of-band support. */ +/* Out-of-band tests */ + +char tmpdir[] = "/tmp/qmp-test-XXXXXX"; +char *fifo_name; + +static void setup_blocking_cmd(void) +{ + if (!mkdtemp(tmpdir)) { + g_error("mkdtemp: %s", strerror(errno)); + } + fifo_name = g_strdup_printf("%s/fifo", tmpdir); + if (mkfifo(fifo_name, 0666)) { + g_error("mkfifo: %s", strerror(errno)); + } +} + +static void cleanup_blocking_cmd(void) +{ + unlink(fifo_name); + rmdir(tmpdir); +} + +static void send_cmd_that_blocks(QTestState *s, const char *id) +{ + qtest_async_qmp(s, "{ 'execute': 'blockdev-add', 'id': %s," + " 'arguments': {" + " 'driver': 'blkdebug', 'node-name': %s," + " 'config': %s," + " 'image': { 'driver': 'null-co' } } }", + id, id, fifo_name); +} + +static void unblock_blocked_cmd(void) +{ + int fd = open(fifo_name, O_WRONLY); + g_assert(fd >= 0); + close(fd); +} + +static void send_oob_cmd_that_fails(QTestState *s, const char *id) +{ + qtest_async_qmp(s, "{ 'execute': 'migrate-pause', 'id': %s," + " 'control': { 'run-oob': true } }", id); +} + +static void recv_cmd_id(QTestState *s, const char *id) +{ + QDict *resp = qtest_qmp_receive(s); + + g_assert_cmpstr(qdict_get_try_str(resp, "id"), ==, id); + qobject_unref(resp); +} + static void test_qmp_oob(void) { QTestState *qts; QDict *resp, *q; - int acks = 0; const QListEntry *entry; QList *capabilities; QString *qstr; - const char *cmd_id; qts = qtest_init_without_qmp_handshake(true, common_args); @@ -185,37 +235,20 @@ static void test_qmp_oob(void) g_assert(qdict_haskey(resp, "error")); qobject_unref(resp); - /* - * First send the "x-oob-test" command with lock=true and - * oob=false, it should hang the dispatcher and main thread; - * later, we send another lock=false with oob=true to continue - * that thread processing. Finally we should receive replies from - * both commands. - */ - qtest_async_qmp(qts, - "{ 'execute': 'x-oob-test'," - " 'arguments': { 'lock': true }, " - " 'id': 'lock-cmd'}"); - qtest_async_qmp(qts, - "{ 'execute': 'x-oob-test', " - " 'arguments': { 'lock': false }, " - " 'control': { 'run-oob': true }, " - " 'id': 'unlock-cmd' }"); - - /* Ignore all events. Wait for 2 acks */ - while (acks < 2) { - resp = qtest_qmp_receive(qts); - cmd_id = qdict_get_str(resp, "id"); - if (!g_strcmp0(cmd_id, "lock-cmd") || - !g_strcmp0(cmd_id, "unlock-cmd")) { - acks++; - } - qobject_unref(resp); - } + /* OOB command overtakes slow in-band command */ + setup_blocking_cmd(); + send_cmd_that_blocks(qts, "ib-blocks-1"); + send_oob_cmd_that_fails(qts, "oob-1"); + recv_cmd_id(qts, "oob-1"); + unblock_blocked_cmd(); + recv_cmd_id(qts, "ib-blocks-1"); + cleanup_blocking_cmd(); qtest_quit(qts); } +/* Query smoke tests */ + static int query_error_class(const char *cmd) { static struct { @@ -392,6 +425,8 @@ static void add_query_tests(QmpSchema *schema) } } +/* Preconfig tests */ + static void test_qmp_preconfig(void) { QDict *rsp, *ret; -- 2.11.0