On 12/5/19 2:12 PM, Cornelia Huck wrote:
On Thu, 5 Dec 2019 14:05:19 +0100
Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> wrote:
Hi Cornelia,
On 12/5/19 12:53 PM, Cornelia Huck wrote:
The Posix implementation of guest-set-time invokes hwclock to
set/retrieve the time to/from the hardware clock. If hwclock
is not available, the user is currently informed that "hwclock
failed to set hardware clock to system time", which is quite
misleading. This may happen e.g. on s390x, which has a different
timekeeping concept anyway.
Let's check for the availability of the hwclock command and
return QERR_UNSUPPORTED for guest-set-time if it is not available.
Reviewed-by: Laszlo Ersek <lersek@xxxxxxxxxx>
Reviewed-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
Reviewed-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Cornelia Huck <cohuck@xxxxxxxxxx>
---
v2->v3:
- added 'static' keyword to hwclock_path
Not sure what tree this is going through; if there's no better place,
I can also take this through the s390 tree.
s390 or trivial trees seems appropriate.
---
qga/commands-posix.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 1c1a165daed8..0be301a4ea77 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -156,6 +156,17 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
pid_t pid;
Error *local_err = NULL;
struct timeval tv;
+ static const char hwclock_path[] = "/sbin/hwclock";
+ static int hwclock_available = -1;
+
+ if (hwclock_available < 0) {
+ hwclock_available = (access(hwclock_path, X_OK) == 0);
+ }
+
+ if (!hwclock_available) {
+ error_setg(errp, QERR_UNSUPPORTED);
In include/qapi/qmp/qerror.h we have:
/*
* These macros will go away, please don't use in new code, and do not
* add new ones!
*/
Sigh, it is really hard to keep track here :( I just copied from other
callers in this file...
Maybe we can replace it by "this feature is not supported on this
architecture"? (or without 'on this architecture').
This is not really architecture specific, you'd get this on any setup
that does not have /sbin/hwclock.
Q: Is libvirt doing anything with such an error message from QEMU? Do
we have the freedom to say e.g "guest-set-time is not supported" or so?
Or is it beneficial to print the same error message for any unsupported
feature?
Cc'ing Markus who added the command and libvir-list.
Using "guest-set-time is not supported" or "this command is not supported":
Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
+ return;
+ }
/* If user has passed a time, validate and set it. */
if (has_time) {
@@ -195,7 +206,7 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
/* Use '/sbin/hwclock -w' to set RTC from the system time,
* or '/sbin/hwclock -s' to set the system time from RTC. */
- execle("/sbin/hwclock", "hwclock", has_time ? "-w" : "-s",
+ execle(hwclock_path, "hwclock", has_time ? "-w" : "-s",
NULL, environ);
_exit(EXIT_FAILURE);
} else if (pid < 0) {
--
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