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authorMarkus Armbruster <armbru@redhat.com>2015-03-11 17:26:31 +0100
committerMarkus Armbruster <armbru@redhat.com>2015-06-22 18:20:39 +0200
commita5ec494e274ddcad6d487e3872e16964ef57e0de (patch)
tree0dc1b33e0bae10ffbdc0b870166f1e691317b517 /qdev-monitor.c
parentd49190c4208f2c556c3a01962a81f8a85d522bb1 (diff)
downloadqemu-arm-a5ec494e274ddcad6d487e3872e16964ef57e0de.tar.gz
qdev-monitor: Stop error avalanche in qbus_find_recursive()
Reproducer: $ qemu-system-x86_64 -nodefaults -device virtio-rng-pci -device virtio-rng-pci -device virtio-rng-device,bus=virtio-bus qemu-system-x86_64: -device virtio-rng-device,bus=virtio-bus: Bus 'virtio-bus' is full qemu-system-x86_64: -device virtio-rng-device,bus=virtio-bus: Bus 'virtio-bus' is full qemu-system-x86_64: -device virtio-rng-device,bus=virtio-bus: Bus 'virtio-bus' not found qbus_find_recursive() reports the "is full" error itself, and leaves reporting "not found" to its caller. The result is confusion. Write it a function contract that permits leaving all error reporting to the caller, and implement it. Update callers to detect and report "is full". Screwed up when commit 1395af6 added the max_dev limit and the "is full" error condition to enforce it. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'qdev-monitor.c')
-rw-r--r--qdev-monitor.c64
1 files changed, 40 insertions, 24 deletions
diff --git a/qdev-monitor.c b/qdev-monitor.c
index d71d1ee520..2c4d4c89bd 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -364,43 +364,55 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem)
return NULL;
}
+static inline bool qbus_is_full(BusState *bus)
+{
+ BusClass *bus_class = BUS_GET_CLASS(bus);
+ return bus_class->max_dev && bus->max_index >= bus_class->max_dev;
+}
+
+/*
+ * Search the tree rooted at @bus for a bus.
+ * If @name, search for a bus with that name. Note that bus names
+ * need not be unique. Yes, that's screwed up.
+ * Else search for a bus that is a subtype of @bus_typename.
+ * If more than one exists, prefer one that can take another device.
+ * Return the bus if found, else %NULL.
+ */
static BusState *qbus_find_recursive(BusState *bus, const char *name,
const char *bus_typename)
{
- BusClass *bus_class = BUS_GET_CLASS(bus);
BusChild *kid;
- BusState *child, *ret;
- int match = 1;
-
- if (name && (strcmp(bus->name, name) != 0)) {
- match = 0;
- } else if (bus_typename && !object_dynamic_cast(OBJECT(bus), bus_typename)) {
- match = 0;
- } else if ((bus_class->max_dev != 0) && (bus_class->max_dev <= bus->max_index)) {
- if (name != NULL) {
- /* bus was explicitly specified: return an error. */
- qerror_report(ERROR_CLASS_GENERIC_ERROR, "Bus '%s' is full",
- bus->name);
- return NULL;
- } else {
- /* bus was not specified: try to find another one. */
- match = 0;
- }
+ BusState *pick, *child, *ret;
+ bool match;
+
+ assert(name || bus_typename);
+ if (name) {
+ match = !strcmp(bus->name, name);
+ } else {
+ match = !!object_dynamic_cast(OBJECT(bus), bus_typename);
}
- if (match) {
- return bus;
+
+ if (match && !qbus_is_full(bus)) {
+ return bus; /* root matches and isn't full */
}
+ pick = match ? bus : NULL;
+
QTAILQ_FOREACH(kid, &bus->children, sibling) {
DeviceState *dev = kid->child;
QLIST_FOREACH(child, &dev->child_bus, sibling) {
ret = qbus_find_recursive(child, name, bus_typename);
- if (ret) {
- return ret;
+ if (ret && !qbus_is_full(ret)) {
+ return ret; /* a descendant matches and isn't full */
+ }
+ if (ret && !pick) {
+ pick = ret;
}
}
}
- return NULL;
+
+ /* root or a descendant matches, but is full */
+ return pick;
}
static BusState *qbus_find(const char *path)
@@ -423,6 +435,10 @@ static BusState *qbus_find(const char *path)
if (!bus) {
qerror_report(QERR_BUS_NOT_FOUND, elem);
return NULL;
+ } else if (qbus_is_full(bus)) {
+ qerror_report(ERROR_CLASS_GENERIC_ERROR, "Bus '%s' is full",
+ elem);
+ return NULL;
}
pos = len;
}
@@ -529,7 +545,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
}
} else if (dc->bus_type != NULL) {
bus = qbus_find_recursive(sysbus_get_default(), NULL, dc->bus_type);
- if (!bus) {
+ if (!bus || qbus_is_full(bus)) {
qerror_report(ERROR_CLASS_GENERIC_ERROR,
"No '%s' bus found for device '%s'",
dc->bus_type, driver);