launch: libvirt: get default QEMU from domcapabilities

Parse the libvirt domain capabilities for the default emulator
capabilities, and get the path to the default QEMU executable.
This commit is contained in:
Pino Toscano
2019-05-24 12:29:34 +02:00
parent 8d453fe9cc
commit 797925cc3c

View File

@@ -134,6 +134,7 @@ struct backend_libvirt_data {
size_t nr_secrets;
char *uefi_code; /* UEFI (firmware) code and variables. */
char *uefi_vars;
char *default_qemu; /* default qemu (from domcapabilities) */
char guestfsd_path[UNIX_PATH_MAX]; /* paths to sockets */
char console_path[UNIX_PATH_MAX];
};
@@ -153,6 +154,7 @@ struct libvirt_xml_params {
};
static int parse_capabilities (guestfs_h *g, const char *capabilities_xml, struct backend_libvirt_data *data);
static int parse_domcapabilities (guestfs_h *g, const char *domcapabilities_xml, struct backend_libvirt_data *data);
static int add_secret (guestfs_h *g, virConnectPtr conn, struct backend_libvirt_data *data, const struct drive *drv);
static int find_secret (guestfs_h *g, const struct backend_libvirt_data *data, const struct drive *drv, const char **type, const char **uuid);
static int have_secret (guestfs_h *g, const struct backend_libvirt_data *data, const struct drive *drv);
@@ -324,6 +326,7 @@ launch_libvirt (guestfs_h *g, void *datav, const char *libvirt_uri)
CLEANUP_FREE void *buf = NULL;
unsigned long version_number;
int uefi_flags;
CLEANUP_FREE char *domcapabilities_xml = NULL;
params.current_proc_is_root = geteuid () == 0;
@@ -419,6 +422,20 @@ launch_libvirt (guestfs_h *g, void *datav, const char *libvirt_uri)
if (parse_capabilities (g, capabilities_xml, data) == -1)
goto cleanup;
domcapabilities_xml = virConnectGetDomainCapabilities (conn, NULL, NULL, NULL,
NULL, 0);
if (!domcapabilities_xml) {
libvirt_error (g, _("could not get libvirt domain capabilities"));
goto cleanup;
}
/* Parse domcapabilities XML.
*/
debug (g, "parsing domcapabilities XML");
if (parse_domcapabilities (g, domcapabilities_xml, data) == -1)
goto cleanup;
/* UEFI code and variables, on architectures where that is required. */
if (guestfs_int_get_uefi (g, &data->uefi_code, &data->uefi_vars,
&uefi_flags) == -1)
@@ -819,6 +836,42 @@ parse_capabilities (guestfs_h *g, const char *capabilities_xml,
return 0;
}
static int
parse_domcapabilities (guestfs_h *g, const char *domcapabilities_xml,
struct backend_libvirt_data *data)
{
CLEANUP_XMLFREEDOC xmlDocPtr doc = NULL;
CLEANUP_XMLXPATHFREECONTEXT xmlXPathContextPtr xpathCtx = NULL;
CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xpathObj = NULL;
doc = xmlReadMemory (domcapabilities_xml, strlen (domcapabilities_xml),
NULL, NULL, XML_PARSE_NONET);
if (doc == NULL) {
error (g, _("unable to parse domain capabilities XML returned by libvirt"));
return -1;
}
xpathCtx = xmlXPathNewContext (doc);
if (xpathCtx == NULL) {
error (g, _("unable to create new XPath context"));
return -1;
}
/* This gives us the default QEMU. */
#define XPATH_EXPR "string(/domainCapabilities/path/text())"
xpathObj = xmlXPathEvalExpression (BAD_CAST XPATH_EXPR, xpathCtx);
if (xpathObj == NULL) {
error (g, _("unable to evaluate XPath expression: %s"), XPATH_EXPR);
return -1;
}
#undef XPATH_EXPR
assert (xpathObj->type == XPATH_STRING);
data->default_qemu = safe_strdup (g, (char *) xpathObj->stringval);
return 0;
}
static int
is_custom_hv (guestfs_h *g)
{
@@ -2014,6 +2067,9 @@ shutdown_libvirt (guestfs_h *g, void *datav, int check_for_errors)
free (data->uefi_vars);
data->uefi_vars = NULL;
free (data->default_qemu);
data->default_qemu = NULL;
return ret;
}