[PATCH 08/13] qemu-io: accept --object iothread

["Denis V. Lunev" <den@openvz.org>]

From: Denis V. Lunev <den@openvz.org>

qemu-io refused "--object iothread,id=t0" with "invalid object type:
iothread", because iothread.c was built into blockdev_ss, which qemu-io
does not link. Move it to block_ss: it wraps an AioContext and has
nothing to do with blockdev, and linking blockdev instead would drag in
os-posix.c, whose qemu_system_killed() every program linking it has to
define.

Collect the --object arguments during option parsing and process them
once qemu_init_main_loop() has run; nothing before that point uses an
object. An iothread created earlier registers the timer lists of its
AioContext with clocks that qemu_init_clocks() then resets, unlinking
them silently: no failure, just timers that never fire.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
CC: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
---
 meson.build | 2 +-
 qemu-io.c   | 9 ++++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build
index cfac634cf1..4c3f6518fd 100644
--- a/meson.build
+++ b/meson.build
@@ -3816,6 +3816,7 @@ if have_block
   block_ss.add(files(
     'block.c',
     'blockjob.c',
+    'iothread.c',
     'job.c',
     'qemu-io-cmds.c',
   ))
@@ -3830,7 +3831,6 @@ if have_block
   blockdev_ss.add(files(
     'blockdev.c',
     'blockdev-nbd.c',
-    'iothread.c',
     'job-qmp.c',
   ))
 
diff --git a/qemu-io.c b/qemu-io.c
index 598d5b1c9c..2b684ccf55 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -532,6 +532,7 @@ int main(int argc, char **argv)
     QDict *opts = NULL;
     const char *format = NULL;
     bool force_share = false;
+    g_autoptr(GPtrArray) objects = g_ptr_array_new();
 
 #ifdef CONFIG_POSIX
     signal(SIGPIPE, SIG_IGN);
@@ -607,7 +608,7 @@ int main(int argc, char **argv)
             force_share = true;
             break;
         case OPTION_OBJECT:
-            user_creatable_process_cmdline(optarg);
+            g_ptr_array_add(objects, optarg);
             break;
         case OPTION_IMAGE_OPTS:
             imageOpts = true;
@@ -630,6 +631,11 @@ int main(int argc, char **argv)
 
     qemu_init_main_loop(&error_fatal);
 
+    /* An iothread object cannot be created before the main loop exists. */
+    for (guint i = 0; i < objects->len; i++) {
+        user_creatable_process_cmdline(g_ptr_array_index(objects, i));
+    }
+
     if (!trace_init_backends()) {
         exit(1);
     }
@@ -686,6 +692,7 @@ int main(int argc, char **argv)
     bdrv_drain_all();
 
     blk_unref(qemuio_blk);
+    user_creatable_cleanup();
     g_free(readline_state);
 
     if (ret < 0) {
-- 
2.53.0