On 10/12/2018 04:18 PM, Markus Armbruster wrote:
Fei Li <f...@suse.com> writes:
On 10/11/2018 09:13 PM, Markus Armbruster wrote:
Fei Li <f...@suse.com> writes:
Add a new Error parameter for vnc_display_init() to handle errors
in its caller: vnc_init_func(), just like vnc_display_open() does.
And let the call trace propagate the Error.
Besides, make vnc_start_worker_thread() return a bool to indicate
whether it succeeds instead of returning nothing.
Signed-off-by: Fei Li <f...@suse.com>
Reviewed-by: Fam Zheng <f...@redhat.com>
---
include/ui/console.h | 2 +-
ui/vnc-jobs.c | 9 ++++++---
ui/vnc-jobs.h | 2 +-
ui/vnc.c | 12 +++++++++---
4 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/include/ui/console.h b/include/ui/console.h
index fb969caf70..c17803c530 100644
--- a/include/ui/console.h
+++ b/include/ui/console.h
@@ -453,7 +453,7 @@ void qemu_display_early_init(DisplayOptions *opts);
void qemu_display_init(DisplayState *ds, DisplayOptions *opts);
/* vnc.c */
-void vnc_display_init(const char *id);
+void vnc_display_init(const char *id, Error **errp);
void vnc_display_open(const char *id, Error **errp);
void vnc_display_add_client(const char *id, int csock, bool skipauth);
int vnc_display_password(const char *id, const char *password);
diff --git a/ui/vnc-jobs.c b/ui/vnc-jobs.c
index 929391f85d..8807d7217c 100644
--- a/ui/vnc-jobs.c
+++ b/ui/vnc-jobs.c
@@ -331,15 +331,18 @@ static bool vnc_worker_thread_running(void)
return queue; /* Check global queue */
}
-void vnc_start_worker_thread(void)
+bool vnc_start_worker_thread(Error **errp)
{
VncJobQueue *q;
- if (vnc_worker_thread_running())
- return ;
+ if (vnc_worker_thread_running()) {
+ goto out;
+ }
q = vnc_queue_init();
qemu_thread_create(&q->thread, "vnc_worker", vnc_worker_thread, q,
QEMU_THREAD_DETACHED);
queue = q; /* Set global queue */
+out:
+ return true;
}
This function cannot fail. Why convert it to Error, and complicate its
caller?
[Issue1]
Actually, this is to pave the way for patch 7/7, in case
qemu_thread_create() fails.
Patch 7/7 is long enough, thus I wrote the patch 1/2/3 separately to mainly
connects the broken errp for callers who initially have the errp.
[I am back... If the other codes in this patches be squashed, maybe
merge [Issue1]
into patch 7/7 looks more intuitive.]
diff --git a/ui/vnc-jobs.h b/ui/vnc-jobs.h
index 59f66bcc35..14640593db 100644
--- a/ui/vnc-jobs.h
+++ b/ui/vnc-jobs.h
@@ -37,7 +37,7 @@ void vnc_job_push(VncJob *job);
void vnc_jobs_join(VncState *vs);
void vnc_jobs_consume_buffer(VncState *vs);
-void vnc_start_worker_thread(void);
+bool vnc_start_worker_thread(Error **errp);
/* Locks */
static inline int vnc_trylock_display(VncDisplay *vd)
diff --git a/ui/vnc.c b/ui/vnc.c
index cf221c83cc..f3806e76db 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3205,7 +3205,7 @@ static const DisplayChangeListenerOps dcl_ops = {
.dpy_cursor_define = vnc_dpy_cursor_define,
};
-void vnc_display_init(const char *id)
+void vnc_display_init(const char *id, Error **errp)
{
VncDisplay *vd;
if (vnc_display_find(id) != NULL) {
return;
}
vd = g_malloc0(sizeof(*vd));
vd->id = strdup(id);
QTAILQ_INSERT_TAIL(&vnc_displays, vd, next);
QTAILQ_INIT(&vd->clients);
vd->expires = TIME_MAX;
if (keyboard_layout) {
trace_vnc_key_map_init(keyboard_layout);
vd->kbd_layout = init_keyboard_layout(name2keysym,
keyboard_layout);
} else {
vd->kbd_layout = init_keyboard_layout(name2keysym, "en-us");
}
if (!vd->kbd_layout) {
exit(1);
Uh, init_keyboard_layout() reports errors to stderr, and the exit(1)
here makes them fatal. Okay before this patch, but inappropriate
afterwards. I'm afraid you have to convert init_keyboard_layout() to
Error first.
[Issue2]
Right. But I notice the returned kbd_layout_t *kbd_layout is a static
value and also
will be used by others, how about passing the errp parameter to
init_keyboard_layout()
as follows? And for its other callers, just pass NULL.
@@ -3222,13 +3222,13 @@ void vnc_display_init(const char *id, Error **errp)
if (keyboard_layout) {
trace_vnc_key_map_init(keyboard_layout);
- vd->kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout);
+ vd->kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout,
errp);
} else {
- vd->kbd_layout = init_keyboard_layout(name2keysym, "en-us");
+ vd->kbd_layout = init_keyboard_layout(name2keysym, "en-us", errp);
}
if (!vd->kbd_layout) {
- exit(1);
+ return;
}
Sounds good to me, except you should pass &error_fatal instead of NULL
to preserve "report error and exit" semantics.
Yes, you are right. I should pass &error_fatal and let the following
error_setg() handle this.
@@ -94,7 +94,7 @@ static kbd_layout_t *parse_keyboard_layout(const
name2keysym_t *table,
f = filename ? fopen(filename, "r") : NULL;
g_free(filename);
if (!f) {
- fprintf(stderr, "Could not read keymap file: '%s'\n", language);
+ error_setg(errp, "could not read keymap file: '%s'\n", language);
return NULL;
}
}
vd->share_policy = VNC_SHARE_POLICY_ALLOW_EXCLUSIVE;
@@ -3235,7 +3235,9 @@ void vnc_display_init(const char *id)
vd->connections_limit = 32;
qemu_mutex_init(&vd->mutex);
- vnc_start_worker_thread();
+ if (!vnc_start_worker_thread(errp)) {
+ return;
+ }
vd->dcl.ops = &dcl_ops;
register_displaychangelistener(&vd->dcl);
@@ -4079,7 +4081,11 @@ int vnc_init_func(void *opaque, QemuOpts *opts, Error
**errp)
char *id = (char *)qemu_opts_id(opts);
assert(id);
- vnc_display_init(id);
+ vnc_display_init(id, &local_err);
+ if (local_err) {
+ error_reportf_err(local_err, "Failed to init VNC server: ");
+ exit(1);
+ }
vnc_display_open(id, &local_err);
if (local_err != NULL) {
error_reportf_err(local_err, "Failed to start VNC server: ");
Conflicts with my "[PATCH 24/31] vl: Clean up error reporting in
vnc_init_func()". Your patch shows that mine is incomplete.
Without my patch, there's no real reason for yours, however. The two
should be squashed together.
Ah, I noticed your patch 24/31. OK, let's squash.
Should I write a new patch by
- updating to error_propagate(...) if vnc_display_init() fails
&&
- modifying [Issue2] ?
Or you do this in your original patch?
If you send a v2 along that lines, I'll probably pick your patch into my
series. Should work even in case your series gets merged first.
Good idea. I will send a separate v2 patch which also include the
above change mentioned in [Issue1].
BTW, for your patch 24/31, the updated passed errp for vnc_init_func
is &error_fatal,
then the system will exit(1) when running error_propagate(...) which calls
error_handle_fatal(...). This means the following two lines will not
be touched.
But if we want the following prepended error message, could we move it
earlier than
the error_propagare? I mean:
if (local_err != NULL) {
- error_reportf_err(local_err, "Failed to start VNC server: ");
- exit(1);
+ error_prepend(&local_err, "Failed to start VNC server: ");
+ error_propagate(errp, local_err);
+ return -1;
}
Both
error_propagate(errp, local_err);
error_prepend(errp, "Failed to start VNC server: ");
and
error_prepend(&local_err, "Failed to start VNC server: ");
error_propagate(errp, local_err);
work. The former is slightly more efficient when errp is null. But
you're right, it fails to include the "Failed to start VNC server: "
prefix with &error_fatal. Thus, the latter is preferrable.
Have a nice day, thanks
Fei
