shutdown: Prepare for use of an enum in reset/shutdown_request

We want to track why a guest was shutdown; in particular, being able
to tell the difference between a guest request (such as ACPI request)
and host request (such as SIGINT) will prove useful to libvirt.
Since all requests eventually end up changing shutdown_requested in
vl.c, the logical change is to make that value track the reason,
rather than its current 0/1 contents.

Since command-line options control whether a reset request is turned
into a shutdown request instead, the same treatment is given to
reset_requested.

This patch adds an internal enum ShutdownCause that describes reasons
that a shutdown can be requested, and changes qemu_system_reset() to
pass the reason through, although for now nothing is actually changed
with regards to what gets reported.  The enum could be exported via
QAPI at a later date, if deemed necessary, but for now, there has not
been a request to expose that much detail to end clients.

For the most part, we turn 0 into SHUTDOWN_CAUSE_NONE, and 1 into
SHUTDOWN_CAUSE_HOST_ERROR; the only specific case where we have enough
information right now to use a different value is when we are reacting
to a host signal.  It will take a further patch to edit all call-sites
that can trigger a reset or shutdown request to properly pass in any
other reasons; this patch includes TODOs to point such places out.

qemu_system_reset() trades its 'bool report' parameter for a
'ShutdownCause reason', with all non-zero values having the same
effect; this lets us get rid of the weird #defines for VMRESET_*
as synonyms for bools.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170515214114.15442-3-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 18 insertions, 5 deletions

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 83c1ceb33e..ba633d75d2 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -33,8 +33,21 @@ VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,
 void qemu_del_vm_change_state_handler(VMChangeStateEntry *e);
 void vm_state_notify(int running, RunState state);
 
-#define VMRESET_SILENT   false
-#define VMRESET_REPORT   true
+/* Enumeration of various causes for shutdown. */
+typedef enum ShutdownCause {
+    SHUTDOWN_CAUSE_NONE,          /* No shutdown request pending */
+    SHUTDOWN_CAUSE_HOST_ERROR,    /* An error prevents further use of guest */
+    SHUTDOWN_CAUSE_HOST_QMP,      /* Reaction to a QMP command, like 'quit' */
+    SHUTDOWN_CAUSE_HOST_SIGNAL,   /* Reaction to a signal, such as SIGINT */
+    SHUTDOWN_CAUSE_HOST_UI,       /* Reaction to UI event, like window close */
+    SHUTDOWN_CAUSE_GUEST_SHUTDOWN,/* Guest shutdown/suspend request, via
+                                     ACPI or other hardware-specific means */
+    SHUTDOWN_CAUSE_GUEST_RESET,   /* Guest reset request, and command line
+                                     turns that into a shutdown */
+    SHUTDOWN_CAUSE_GUEST_PANIC,   /* Guest panicked, and command line turns
+                                     that into a shutdown */
+    SHUTDOWN_CAUSE__MAX,
+} ShutdownCause;
 
 void vm_start(void);
 int vm_prepare_start(void);
@@ -62,10 +75,10 @@ void qemu_system_debug_request(void);
 void qemu_system_vmstop_request(RunState reason);
 void qemu_system_vmstop_request_prepare(void);
 bool qemu_vmstop_requested(RunState *r);
-int qemu_shutdown_requested_get(void);
-int qemu_reset_requested_get(void);
+ShutdownCause qemu_shutdown_requested_get(void);
+ShutdownCause qemu_reset_requested_get(void);
 void qemu_system_killed(int signal, pid_t pid);
-void qemu_system_reset(bool report);
+void qemu_system_reset(ShutdownCause reason);
 void qemu_system_guest_panicked(GuestPanicInformation *info);
 size_t qemu_target_page_size(void);