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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 09/18] libxl: disallow attaching the same device more than once
Originally the code allowed users to attach the same device more than
once. It just stupidly overwrites xenstore entries. This is bogus as
frontend will be very confused.
Introduce a helper function to check if the device to be written to
xenstore already exists. A new error code is also introduced.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
tools/libxl/libxl.c | 50 ++++++++++++++++++++++++++++++++++++++++++
tools/libxl/libxl_device.c | 19 ++++++++++++++++
tools/libxl/libxl_internal.h | 3 +++
tools/libxl/libxl_pci.c | 12 ++++++++++
tools/libxl/libxl_types.idl | 1 +
5 files changed, 85 insertions(+)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 01dffa0..e6fe238 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1906,6 +1906,15 @@ void libxl__device_vtpm_add(libxl__egc *egc, uint32_t
domid,
rc = libxl__device_from_vtpm(gc, domid, vtpm, device);
if ( rc != 0 ) goto out;
+ rc = libxl__device_exists(gc, XBT_NULL, device);
+ if (rc < 0) goto out;
+ if (rc == 1) { /* already exists in xenstore */
+ LOG(ERROR, "device already exists in xenstore");
+ aodev->action = LIBXL__DEVICE_ACTION_ADD; /* for error message */
+ rc = ERROR_DEVICE_EXISTS;
+ goto out;
+ }
+
flexarray_append(back, "frontend-id");
flexarray_append(back, GCSPRINTF("%d", domid));
flexarray_append(back, "online");
@@ -2154,6 +2163,13 @@ int libxl__device_from_disk(libxl__gc *gc, uint32_t
domid,
*
* The passed get_vdev function is also in charge of printing
* the corresponding error message when appropiate.
+ *
+ * Note:
+ *
+ * The presence of get_vdev is also used to distinguish two
+ * cases: if get_vdev != NULL, then it is called by local attach
+ * function to run bootloader, otherwise it is called by
+ * libxl__device_disk_add wrapper.
*/
static void device_disk_add(libxl__egc *egc, uint32_t domid,
libxl_device_disk *disk,
@@ -2177,6 +2193,31 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
goto out;
}
+ /* If we're not doing local attach, we're trying to do
+ * "block-attach". We already have a valid vdev at this point, and
+ * we need to check if this device already exists in xenstore.
+ */
+ if (!get_vdev) {
+ /* Construct libxl__device from libxl_device_disk */
+ libxl__device_disk_setdefault(gc, disk);
+ GCNEW(device);
+ rc = libxl__device_from_disk(gc, domid, disk, device);
+ if (rc != 0) {
+ LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Invalid or unsupported"
+ " virtual disk identifier %s", disk->vdev);
+ goto out;
+ }
+
+ rc = libxl__device_exists(gc, XBT_NULL, device);
+ if (rc < 0) goto out;
+ if (rc == 1) { /* already exists in xenstore */
+ LOG(ERROR, "device already exists in xenstore");
+ aodev->action = LIBXL__DEVICE_ACTION_ADD; /* for error message */
+ rc = ERROR_DEVICE_EXISTS;
+ goto out;
+ }
+ }
+
for (;;) {
rc = libxl__xs_transaction_start(gc, &t);
if (rc) goto out;
@@ -3011,6 +3052,15 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t
domid,
rc = libxl__device_from_nic(gc, domid, nic, device);
if ( rc != 0 ) goto out;
+ rc = libxl__device_exists(gc, XBT_NULL, device);
+ if (rc < 0) goto out;
+ if (rc == 1) { /* already exists in xenstore */
+ LOG(ERROR, "device already exists in xenstore");
+ aodev->action = LIBXL__DEVICE_ACTION_ADD; /* for error message */
+ rc = ERROR_DEVICE_EXISTS;
+ goto out;
+ }
+
flexarray_append(back, "frontend-id");
flexarray_append(back, libxl__sprintf(gc, "%d", domid));
flexarray_append(back, "online");
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index f8a2e1b..045212f 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -40,6 +40,25 @@ char *libxl__device_backend_path(libxl__gc *gc,
libxl__device *device)
device->domid, device->devid);
}
+/* Returns 1 if device exists, 0 if not, ERROR_* (<0) on error. */
+int libxl__device_exists(libxl__gc *gc, xs_transaction_t t,
+ libxl__device *device)
+{
+ int rc;
+ char *be_path = libxl__device_backend_path(gc, device);
+ const char *dir;
+
+ be_path = libxl__device_backend_path(gc, device);
+ rc = libxl__xs_read_checked(gc, t, be_path, &dir);
+
+ if (rc)
+ return rc;
+
+ if (dir)
+ return 1;
+ return 0;
+}
+
int libxl__parse_backend_path(libxl__gc *gc,
const char *path,
libxl__device *dev)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 02708c7..1b44c2c 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1031,6 +1031,9 @@ _hidden int libxl__device_console_add(libxl__gc *gc,
uint32_t domid,
libxl__device_console *console,
libxl__domain_build_state *state);
+/* Returns 1 if device exists, 0 if not, ERROR_* (<0) on error. */
+_hidden int libxl__device_exists(libxl__gc *gc, xs_transaction_t t,
+ libxl__device *device);
_hidden int libxl__device_generic_add(libxl__gc *gc, xs_transaction_t t,
libxl__device *device, char **bents, char **fents, char **ro_fents);
_hidden char *libxl__device_backend_path(libxl__gc *gc, libxl__device *device);
diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
index 0500cf3..e05f047 100644
--- a/tools/libxl/libxl_pci.c
+++ b/tools/libxl/libxl_pci.c
@@ -1042,6 +1042,7 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
unsigned int orig_vdev, pfunc_mask;
libxl_device_pci *assigned;
int num_assigned, i, rc;
+ libxl__device device;
int stubdomid = 0;
if (libxl__domain_type(gc, domid) == LIBXL_DOMAIN_TYPE_HVM) {
@@ -1059,6 +1060,17 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
libxl_device_pci *pcide
rc = libxl__device_pci_setdefault(gc, pcidev);
if (rc) goto out;
+ if (!starting) {
+ libxl__device_from_pcidev(gc, domid, pcidev, &device);
+ rc = libxl__device_exists(gc, XBT_NULL, &device);
+ if (rc < 0) goto out;
+ if (rc == 1) { /* already exists in xenstore */
+ LOG(ERROR, "device already exists in xenstore");
+ rc = ERROR_DEVICE_EXISTS;
+ goto out;
+ }
+ }
+
if (pcidev->seize && !pciback_dev_is_assigned(gc, pcidev)) {
rc = libxl__device_pci_assignable_add(gc, pcidev, 1);
if ( rc )
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index d0a373b..1beb63d 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -60,6 +60,7 @@ libxl_error = Enumeration("error", [
(-14, "UNKNOWN_CHILD"),
(-15, "LOCK_FAIL"),
(-16, "JSON_CONFIG_EMPTY"),
+ (-17, "DEVICE_EXISTS"),
], value_namespace = "")
libxl_domain_type = Enumeration("domain_type", [
--
1.7.10.4
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