8:45 a.m.
From: "Daniel P. Berrange" <berrange(a)redhat.com>
Currently if the URI passed to virConnectOpen* is NULL, then we
- Look for LIBVIRT_DEFAULT_URI env var
- Probe for drivers
This changes it so that
- Look for LIBVIRT_DEFAULT_URI env var
- Look for 'uri_default' in $HOME/.libvirt/libvirt.conf
- Probe for drivers
---
docs/uri.html.in | 16 ++++++++-
src/libvirt.c | 107 +++++++++++++++++++++++++++++++++++++-----------------
src/libvirt.conf | 6 +++
tools/virsh.pod | 4 ++-
4 files changed, 98 insertions(+), 35 deletions(-)
diff --git a/docs/uri.html.in b/docs/uri.html.in
index 79f8786..2f76e8f 100644
--- a/docs/uri.html.in
+++ b/docs/uri.html.in
@@ -52,6 +52,19 @@ uri_aliases = [
set, no alias lookup will be attempted.
</p>
+ <h2><a name="URI_default">Default URI
choice</a></h2>
+
+ <p>
+If the URI passed to <code>virConnectOpen*</code> is NULL, then libvirt will
use the following
+logic to determine what URI to use.
+</p>
+
+ <ol>
+ <li>The environment variable
<code>LIBVIRT_DEFAULT_URI</code></li>
+ <li>The client configuration file <code>uri_default</code>
parameter</li>
+ <li>Probe each hypervisor in turn until one that works is found</li>
+ </ol>
+
<h2>
<a name="URI_virsh">Specifying URIs to virsh, virt-manager and
virt-install</a>
</h2>
@@ -64,7 +77,8 @@ virsh <b>-c test:///default</b> list
<p>
If virsh finds the environment variable
<code>VIRSH_DEFAULT_CONNECT_URI</code> set, it will try this URI by
-default.
+default. Use of this environment variable is, however, deprecated
+now that libvirt supports <code>LIBVIRT_DEFAULT_URI</code> itself.
</p>
<p>
When using the interactive virsh shell, you can also use the
diff --git a/src/libvirt.c b/src/libvirt.c
index e916aa0..1c0cdf7 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -961,7 +961,7 @@ error:
}
static char *
-virConnectConfigFile(void)
+virConnectGetConfigFilePath(void)
{
char *path;
if (geteuid() == 0) {
@@ -989,6 +989,33 @@ error:
return NULL;
}
+static int
+virConnectGetConfigFile(virConfPtr *conf)
+{
+ char *filename = NULL;
+ int ret = -1;
+
+ *conf = NULL;
+
+ if (!(filename = virConnectGetConfigFilePath()))
+ goto cleanup;
+
+ if (!virFileExists(filename)) {
+ ret = 0;
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Loading config file '%s'", filename);
+ if (!(*conf = virConfReadFile(filename, 0)))
+ goto cleanup;
+
+ ret = 0;
+
+cleanup:
+ VIR_FREE(filename);
+ return ret;
+}
+
#define URI_ALIAS_CHARS
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-"
static int
@@ -1050,35 +1077,45 @@ virConnectOpenFindURIAliasMatch(virConfValuePtr value, const char
*alias, char *
}
static int
-virConnectOpenResolveURIAlias(const char *alias, char **uri)
+virConnectOpenResolveURIAlias(virConfPtr conf,
+ const char *alias, char **uri)
{
- char *config = NULL;
int ret = -1;
- virConfPtr conf = NULL;
virConfValuePtr value = NULL;
*uri = NULL;
- if (!(config = virConnectConfigFile()))
- goto cleanup;
-
- if (!virFileExists(config)) {
- ret = 0;
- goto cleanup;
- }
-
- VIR_DEBUG("Loading config file '%s'", config);
- if (!(conf = virConfReadFile(config, 0)))
- goto cleanup;
-
if ((value = virConfGetValue(conf, "uri_aliases")))
ret = virConnectOpenFindURIAliasMatch(value, alias, uri);
else
ret = 0;
+ return ret;
+}
+
+
+static int
+virConnectGetDefaultURI(virConfPtr conf,
+ const char **name)
+{
+ int ret = -1;
+ virConfValuePtr value = NULL;
+ char *defname = getenv("LIBVIRT_DEFAULT_URI");
+ if (defname && *defname) {
+ VIR_DEBUG("Using LIBVIRT_DEFAULT_URI '%s'", defname);
+ *name = defname;
+ } else if ((value = virConfGetValue(conf, "uri_default"))) {
+ if (value->type != VIR_CONF_STRING) {
+ virLibConnError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Expected a string for 'uri_default' config
parameter"));
+ goto cleanup;
+ }
+ VIR_DEBUG("Using config file uri '%s'", value->str);
+ *name = value->str;
+ }
+
+ ret = 0;
cleanup:
- virConfFree(conf);
- VIR_FREE(config);
return ret;
}
@@ -1089,6 +1126,7 @@ do_open (const char *name,
{
int i, res;
virConnectPtr ret;
+ virConfPtr conf = NULL;
virResetLastError();
@@ -1096,20 +1134,20 @@ do_open (const char *name,
if (ret == NULL)
return NULL;
+ if (virConnectGetConfigFile(&conf) < 0)
+ goto failed;
+
+ if (name && name[0] == '\0')
+ name = NULL;
+
/*
* If no URI is passed, then check for an environment string if not
* available probe the compiled in drivers to find a default hypervisor
* if detectable.
*/
- if (!name || name[0] == '\0') {
- char *defname = getenv("LIBVIRT_DEFAULT_URI");
- if (defname && *defname) {
- VIR_DEBUG("Using LIBVIRT_DEFAULT_URI %s", defname);
- name = defname;
- } else {
- name = NULL;
- }
- }
+ if (!name &&
+ virConnectGetDefaultURI(conf, &name) < 0)
+ goto failed;
if (name) {
char *alias = NULL;
@@ -1124,7 +1162,7 @@ do_open (const char *name,
name = "xen:///";
if (!(flags & VIR_CONNECT_NO_ALIASES) &&
- virConnectOpenResolveURIAlias(name, &alias) < 0)
+ virConnectOpenResolveURIAlias(conf, name, &alias) < 0)
goto failed;
ret->uri = virURIParse (alias ? alias : name);
@@ -1308,9 +1346,12 @@ do_open (const char *name,
}
}
+ virConfFree(conf);
+
return ret;
failed:
+ virConfFree(conf);
virUnrefConnect(ret);
return NULL;
@@ -1325,11 +1366,11 @@ failed:
*
* Returns a pointer to the hypervisor connection or NULL in case of error
*
- * If @name is NULL then probing will be done to determine a suitable
- * default driver to activate. This involves trying each hypervisor
- * in turn until one successfully opens. If the LIBVIRT_DEFAULT_URI
- * environment variable is set, then it will be used in preference
- * to probing for a driver.
+ * If @name is NULL, if the LIBVIRT_DEFAULT_URI environment variable is set,
+ * then it will be used. Otherwise if the client configuration file
+ * has the "uri_default" parameter set, then it will be used. Finally
+ * probing will be done to determine a suitable default driver to activate.
+ * This involves trying each hypervisor in turn until one successfully opens.
*
* If connecting to an unprivileged hypervisor driver which requires
* the libvirtd daemon to be active, it will automatically be launched
diff --git a/src/libvirt.conf b/src/libvirt.conf
index c54903c..016cd24 100644
--- a/src/libvirt.conf
+++ b/src/libvirt.conf
@@ -10,3 +10,9 @@
# "hail=qemu+ssh://root@hail.cloud.example.com/system",
# "sleet=qemu+ssh://root@sleet.cloud.example.com/system",
#]
+
+#
+# This can be used to prevent probing of the hypervisor
+# driver when no URI is supplied by the application.
+
+#uri_default = "qemu:///system"
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 64b00ee..4cc91cc 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -2632,7 +2632,9 @@ The file to log virsh debug messages.
=item VIRSH_DEFAULT_CONNECT_URI
The hypervisor to connect to by default. Set this to a URI, in the same
-format as accepted by the B<connect> option.
+format as accepted by the B<connect> option. This environment variable
+is deprecated in favour of the global B<LIVIRT_DEFAULT_URI> variable
+which serves the same purpose.
=item VISUAL
--
1.7.7.6