@@ -550,8 +550,9 @@ static void xen_console_device_create(XenBackendInstance *backend,
goto fail;
}
- if (xs_node_scanf(xsh, XBT_NULL, fe, "type", errp, "%ms", &type) != 1) {
- error_prepend(errp, "failed to read console device type: ");
+ type = xs_node_read(xsh, XBT_NULL, fe, "type");
+ if (!type) {
+ error_setg(errp, "failed to read console device type");
goto fail;
}
@@ -568,7 +569,8 @@ static void xen_console_device_create(XenBackendInstance *backend,
snprintf(label, sizeof(label), "xencons%ld", number);
- if (xs_node_scanf(xsh, XBT_NULL, fe, "output", NULL, "%ms", &output) == 1) {
+ output = xs_node_read(xsh, XBT_NULL, fe, "output");
+ if (!output) {
/*
* FIXME: sure we want to support implicit
* muxed monitors here?
@@ -582,8 +584,8 @@ static void xen_console_device_create(XenBackendInstance *backend,
} else if (number) {
cd = serial_hd(number);
if (!cd) {
- error_prepend(errp, "console: No serial device #%ld found: ",
- number);
+ error_setg(errp, "console: No serial device #%ld found",
+ number);
goto fail;
}
} else {
@@ -142,6 +142,18 @@ int xs_node_scanf(struct qemu_xs_handle *h, xs_transaction_t tid,
return rc;
}
+char *xs_node_read(struct qemu_xs_handle *h, xs_transaction_t tid,
+ const char *node, const char *key)
+{
+ char *path = (strlen(node) != 0) ? g_strdup_printf("%s/%s", node, key)
+ : g_strdup(key);
+ char *value = qemu_xen_xs_read(h, tid, path, NULL);
+
+ g_free(path);
+
+ return value;
+}
+
struct qemu_xs_watch *xs_node_watch(struct qemu_xs_handle *h, const char *node,
const char *key, xs_watch_fn fn,
void *opaque, Error **errp)
@@ -156,8 +156,8 @@ again:
!strcmp(key[i], "hotplug-status"))
continue;
- if (xs_node_scanf(xenbus->xsh, tid, path, key[i], NULL, "%ms",
- &val) == 1) {
+ val = xs_node_read(xenbus->xsh, tid, path, key[i]);
+ if (val) {
qdict_put_str(opts, key[i], val);
free(val);
}
@@ -37,6 +37,8 @@ int xs_node_scanf(struct qemu_xs_handle *h, xs_transaction_t tid,
const char *node, const char *key, Error **errp,
const char *fmt, ...)
G_GNUC_SCANF(6, 7);
+char *xs_node_read(struct qemu_xs_handle *h, xs_transaction_t tid,
+ const char *node, const char *key);
/* Watch node/key unless node is empty, in which case watch key */
struct qemu_xs_watch *xs_node_watch(struct qemu_xs_handle *h, const char *node,
The 'm' parameter used to request auto-allocation of the destination variable is not supported on FreeBSD, and as such leads to failures to parse. What's more, the current usage of '%ms' with xs_node_scanf() is pointless, as it just leads to a double allocation of the same string. Instead introduce and use xs_node_read() to read the whole xenstore node. Additionally fix the errors paths to not use error_prepend(), as that could lead to a segmentation fault because xs_node_scanf() only initializes errp when returning a value smaller than 0: Program terminated with signal SIGSEGV, Segmentation fault. Address not mapped to object. fmt=0x15c4dfeade42 "failed to read console device type: ", ap=0x15cd0165ab50) at ../qemu-xen-dir-remote/util/error.c:142 142 g_string_append(newmsg, (*errp)->msg); [...] (gdb) bt (errp=0x15cd0165ae10, fmt=0x15c4dfeade42 "failed to read console device type: ", ap=0x15cd0165ab50) at ../qemu-xen-dir-remote/util/error.c:142 (errp=0x15cd0165ae10, fmt=0x15c4dfeade42 "failed to read console device type: ") at ../qemu-xen-dir-remote/util/error.c:152 (backend=0x43944de00660, opts=0x43944c929000, errp=0x15cd0165ae10) at ../qemu-xen-dir-remote/hw/char/xen_console.c:555 With the change to use xs_node_read() instead of xs_node_scanf() errp will never be initialized, and hence error_setg() should be used unconditionally. Fixes: a783f8ad4ec9 ('xen: add a mechanism to automatically create XenDevice-s...') Fixes: 9b7737469080 ('hw/xen: update Xen console to XenDevice model') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Changes since v1: - Introduce xs_node_read() helper. - Merge with errp fixes. --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony PERARD <anthony@xenproject.org> Cc: Paul Durrant <paul@xen.org> Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com> Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: xen-devel@lists.xenproject.org --- hw/char/xen_console.c | 12 +++++++----- hw/xen/xen-bus-helper.c | 12 ++++++++++++ hw/xen/xen-bus.c | 4 ++-- include/hw/xen/xen-bus-helper.h | 2 ++ 4 files changed, 23 insertions(+), 7 deletions(-)