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qga: Clean up fragile use of error_is_set()

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Using error_is_set(ERRP) to find out whether a function failed is
either wrong, fragile, or unnecessarily opaque.  It's wrong when ERRP
may be null, because errors go undetected when it is.  It's fragile
when proving ERRP non-null involves a non-local argument.  Else, it's
unnecessarily opaque (see commit 84d18f0).

The error_is_set(errp) in the guest agent command handler functions
are merely fragile, because all chall chains (do_qmp_dispatch() via
the generated marshalling functions) pass a non-null errp argument.

Make the code more robust and more obviously correct: receive the
error in a local variable, then propagate it through the parameter.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
This commit is contained in:
Markus Armbruster 2014-05-02 13:26:38 +02:00 committed by Luiz Capitulino
parent ee16ce9337
commit 0f230bf70e
2 changed files with 40 additions and 20 deletions
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22
qga/commands-posix.c
View File

@ -1067,8 +1067,11 @@ out:
void qmp_guest_suspend_disk(Error **errp)
{
bios_supports_mode("pm-is-supported", "--hibernate", "disk", errp);
if (error_is_set(errp)) {
Error *local_err = NULL;
bios_supports_mode("pm-is-supported", "--hibernate", "disk", &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
@ -1077,8 +1080,11 @@ void qmp_guest_suspend_disk(Error **errp)
void qmp_guest_suspend_ram(Error **errp)
{
bios_supports_mode("pm-is-supported", "--suspend", "mem", errp);
if (error_is_set(errp)) {
Error *local_err = NULL;
bios_supports_mode("pm-is-supported", "--suspend", "mem", &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
@ -1087,8 +1093,12 @@ void qmp_guest_suspend_ram(Error **errp)
void qmp_guest_suspend_hybrid(Error **errp)
{
bios_supports_mode("pm-is-supported", "--suspend-hybrid", NULL, errp);
if (error_is_set(errp)) {
Error *local_err = NULL;
bios_supports_mode("pm-is-supported", "--suspend-hybrid", NULL,
&local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}

38
qga/commands-win32.c
View File

@ -87,6 +87,7 @@ static void execute_async(DWORD WINAPI (*func)(LPVOID), LPVOID opaque,
void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
{
Error *local_err = NULL;
UINT shutdown_flag = EWX_FORCE;
slog("guest-shutdown called, mode: %s", mode);
@ -105,8 +106,9 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
/* Request a shutdown privilege, but try to shut down the system
anyway. */
acquire_privilege(SE_SHUTDOWN_NAME, errp);
if (error_is_set(errp)) {
acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
@ -191,14 +193,16 @@ int64_t qmp_guest_fsfreeze_freeze(Error **errp)
/* cannot risk guest agent blocking itself on a write in this state */
ga_set_frozen(ga_state);
qga_vss_fsfreeze(&i, errp, true);
if (error_is_set(errp)) {
qga_vss_fsfreeze(&i, &local_err, true);
if (local_err) {
error_propagate(errp, local_err);
goto error;
}
return i;
error:
local_err = NULL;
qmp_guest_fsfreeze_thaw(&local_err);
if (local_err) {
g_debug("cleanup thaw: %s", error_get_pretty(local_err));
@ -313,28 +317,32 @@ static DWORD WINAPI do_suspend(LPVOID opaque)
void qmp_guest_suspend_disk(Error **errp)
{
Error *local_err = NULL;
GuestSuspendMode *mode = g_malloc(sizeof(GuestSuspendMode));
*mode = GUEST_SUSPEND_MODE_DISK;
check_suspend_mode(*mode, errp);
acquire_privilege(SE_SHUTDOWN_NAME, errp);
execute_async(do_suspend, mode, errp);
check_suspend_mode(*mode, &local_err);
acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
execute_async(do_suspend, mode, &local_err);
if (error_is_set(errp)) {
if (local_err) {
error_propagate(errp, local_err);
g_free(mode);
}
}
void qmp_guest_suspend_ram(Error **errp)
{
Error *local_err = NULL;
GuestSuspendMode *mode = g_malloc(sizeof(GuestSuspendMode));
*mode = GUEST_SUSPEND_MODE_RAM;
check_suspend_mode(*mode, errp);
acquire_privilege(SE_SHUTDOWN_NAME, errp);
execute_async(do_suspend, mode, errp);
check_suspend_mode(*mode, &local_err);
acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
execute_async(do_suspend, mode, &local_err);
if (error_is_set(errp)) {
if (local_err) {
error_propagate(errp, local_err);
g_free(mode);
}
}
@ -375,6 +383,7 @@ int64_t qmp_guest_get_time(Error **errp)
void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
{
Error *local_err = NULL;
SYSTEMTIME ts;
FILETIME tf;
LONGLONG time;
@ -406,8 +415,9 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
}
}
acquire_privilege(SE_SYSTEMTIME_NAME, errp);
if (error_is_set(errp)) {
acquire_privilege(SE_SYSTEMTIME_NAME, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}