X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=blobdiff_plain;f=src%2Fvirt.c;h=58cb999d84c4b7510f8ce87d986420af6162f0ab;hp=2c6be3c6a2392ab8242d1f4cee9c0d1445844385;hb=be3b028d7f2fadd8d2107a419393511e4510d0a4;hpb=4838ec3326d2970e6afe3cde6b368aeae840b969

diff --git a/src/virt.c b/src/virt.c
index 2c6be3c..58cb999 100644
--- a/src/virt.c
+++ b/src/virt.c
@@ -53,12 +53,20 @@ init_libxml2 (void)
   LIBXML_TEST_VERSION;
 }
 
+static void
+ignore_errors (void *ignore, virErrorPtr ignore2)
+{
+  /* empty */
+}
+
 struct guestfs___add_libvirt_dom_argv {
   uint64_t bitmask;
 #define GUESTFS___ADD_LIBVIRT_DOM_READONLY_BITMASK (UINT64_C(1)<<0)
   int readonly;
 #define GUESTFS___ADD_LIBVIRT_DOM_IFACE_BITMASK (UINT64_C(1)<<1)
   const char *iface;
+#define GUESTFS___ADD_LIBVIRT_DOM_LIVE_BITMASK (UINT64_C(1)<<2)
+  int live;
 };
 
 static int guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom, const struct guestfs___add_libvirt_dom_argv *optargs);
@@ -73,6 +81,8 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
   int r = -1;
   const char *libvirturi;
   int readonly;
+  int live;
+  int allowuuid;
   const char *iface;
   struct guestfs___add_libvirt_dom_argv optargs2 = { .bitmask = 0 };
 
@@ -82,6 +92,15 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
              ? optargs->readonly : 0;
   iface = optargs->bitmask & GUESTFS_ADD_DOMAIN_IFACE_BITMASK
           ? optargs->iface : NULL;
+  live = optargs->bitmask & GUESTFS_ADD_DOMAIN_LIVE_BITMASK
+         ? optargs->live : 0;
+  allowuuid = optargs->bitmask & GUESTFS_ADD_DOMAIN_ALLOWUUID_BITMASK
+            ? optargs->allowuuid : 0;
+
+  if (live && readonly) {
+    error (g, _("you cannot set both live and readonly flags"));
+    return -1;
+  }
 
   /* Connect to libvirt, find the domain. */
   conn = virConnectOpenReadOnly (libvirturi);
@@ -92,7 +111,20 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
     goto cleanup;
   }
 
-  dom = virDomainLookupByName (conn, domain_name);
+  /* Suppress default behaviour of printing errors to stderr.  Note
+   * you can't set this to NULL to ignore errors; setting it to NULL
+   * restores the default error handler ...
+   */
+  virConnSetErrorFunc (conn, NULL, ignore_errors);
+
+  /* Try UUID first. */
+  if (allowuuid)
+    dom = virDomainLookupByUUIDString (conn, domain_name);
+
+  /* Try ordinary domain name. */
+  if (!dom)
+    dom = virDomainLookupByName (conn, domain_name);
+
   if (!dom) {
     err = virGetLastError ();
     error (g, _("no libvirt domain called '%s': %s"),
@@ -108,6 +140,10 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
     optargs2.bitmask |= GUESTFS___ADD_LIBVIRT_DOM_IFACE_BITMASK;
     optargs2.iface = iface;
   }
+  if (live) {
+    optargs2.bitmask |= GUESTFS___ADD_LIBVIRT_DOM_LIVE_BITMASK;
+    optargs2.live = live;
+  }
 
   r = guestfs___add_libvirt_dom (g, dom, &optargs2);
 
@@ -196,8 +232,8 @@ guestfs___for_each_disk (guestfs_h *g,
     assert (xptype->nodesetval->nodeTab[0]);
     assert (xptype->nodesetval->nodeTab[0]->type == XML_ATTRIBUTE_NODE);
     xmlAttrPtr attr = (xmlAttrPtr) xptype->nodesetval->nodeTab[0];
-    xmlXPathFreeObject (xptype);
     char *type = (char *) xmlNodeListGetString (doc, attr->children, 1);
+    xmlXPathFreeObject (xptype);
 
     xmlXPathObjectPtr xpfilename;
 
@@ -282,49 +318,63 @@ guestfs___for_each_disk (guestfs_h *g,
   return r;
 }
 
-static int
-add_disk (guestfs_h *g, const char *filename, const char *format,
-          void *optargs_vp)
-{
-  struct guestfs_add_drive_opts_argv *optargs = optargs_vp;
-
-  if (format) {
-    optargs->bitmask |= GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
-    optargs->format = format;
-  } else
-    optargs->bitmask &= ~GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
+/* This was proposed as an external API, but it's not quite baked yet. */
 
-  return guestfs__add_drive_opts (g, filename, optargs);
-}
+static int add_disk (guestfs_h *g, const char *filename, const char *format, void *optargs_vp);
+static int connect_live (guestfs_h *g, virDomainPtr dom);
 
-/* This was proposed as an external API, but it's not quite baked yet. */
 static int
 guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
                            const struct guestfs___add_libvirt_dom_argv *optargs)
 {
-  int r = -1;
-  virErrorPtr err;
-  int cmdline_pos;
-
-  cmdline_pos = guestfs___checkpoint_cmdline (g);
+  size_t cmdline_pos;
+  int r;
+  int readonly;
+  const char *iface;
+  int live;
 
-  int readonly =
+  readonly =
     optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_READONLY_BITMASK
     ? optargs->readonly : 0;
-  const char *iface =
+  iface =
     optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_IFACE_BITMASK
     ? optargs->iface : NULL;
+  live =
+    optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_LIVE_BITMASK
+    ? optargs->live : 0;
+
+  if (live && readonly) {
+    error (g, _("you cannot set both live and readonly flags"));
+    return -1;
+  }
 
   if (!readonly) {
     virDomainInfo info;
+    virErrorPtr err;
+    int vm_running;
+
     if (virDomainGetInfo (dom, &info) == -1) {
       err = virGetLastError ();
       error (g, _("error getting domain info: %s"), err->message);
-      goto cleanup;
+      return -1;
     }
-    if (info.state != VIR_DOMAIN_SHUTOFF) {
-      error (g, _("error: domain is a live virtual machine.\nYou must use readonly access because write access to a running virtual machine\ncan cause disk corruption."));
-      goto cleanup;
+    vm_running = info.state != VIR_DOMAIN_SHUTOFF;
+
+    if (vm_running) {
+      /* If the caller specified the 'live' flag, then they want us to
+       * try to connect to guestfsd if the domain is running.  Note
+       * that live readonly connections are not possible.
+       */
+      if (live)
+        return connect_live (g, dom);
+
+      /* Dangerous to modify the disks of a running VM. */
+      error (g, _("error: domain is a live virtual machine.\n"
+                  "Writing to the disks of a running virtual machine can cause disk corruption.\n"
+                  "Either use read-only access, or if the guest is running the guestfsd daemon\n"
+                  "specify live access.  In most libguestfs tools these options are --ro or\n"
+                  "--live respectively.  Consult the documentation for further information."));
+      return -1;
     }
   }
 
@@ -339,10 +389,125 @@ guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
     optargs2.iface = iface;
   }
 
+  /* Checkpoint the command line around the operation so that either
+   * all disks are added or none are added.
+   */
+  cmdline_pos = guestfs___checkpoint_cmdline (g);
   r = guestfs___for_each_disk (g, dom, add_disk, &optargs2);
+  if (r == -1)
+    guestfs___rollback_cmdline (g, cmdline_pos);
+
+  return r;
+}
+
+static int
+add_disk (guestfs_h *g, const char *filename, const char *format,
+          void *optargs_vp)
+{
+  struct guestfs_add_drive_opts_argv *optargs = optargs_vp;
+
+  if (format) {
+    optargs->bitmask |= GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
+    optargs->format = format;
+  } else
+    optargs->bitmask &= ~GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
+
+  return guestfs__add_drive_opts (g, filename, optargs);
+}
+
+static int
+connect_live (guestfs_h *g, virDomainPtr dom)
+{
+  int i, r = -1;
+  virErrorPtr err;
+  xmlDocPtr doc = NULL;
+  xmlXPathContextPtr xpathCtx = NULL;
+  xmlXPathObjectPtr xpathObj = NULL;
+  char *xml = NULL;
+  char *path = NULL;
+  char *attach_method = NULL;
+
+  /* Domain XML. */
+  xml = virDomainGetXMLDesc (dom, 0);
+
+  if (!xml) {
+    err = virGetLastError ();
+    error (g, _("error reading libvirt XML information: %s"),
+           err->message);
+    goto cleanup;
+  }
+
+  /* Parse XML to document. */
+  doc = xmlParseMemory (xml, strlen (xml));
+  if (doc == NULL) {
+    error (g, _("unable to parse XML information returned by libvirt"));
+    goto cleanup;
+  }
+
+  xpathCtx = xmlXPathNewContext (doc);
+  if (xpathCtx == NULL) {
+    error (g, _("unable to create new XPath context"));
+    goto cleanup;
+  }
+
+  /* This gives us a set of all the <channel> nodes related to the
+   * guestfsd virtio-serial channel.
+   */
+  xpathObj = xmlXPathEvalExpression (BAD_CAST
+      "//devices/channel[@type=\"unix\" and "
+                        "./source/@mode=\"bind\" and "
+                        "./source/@path and "
+                        "./target/@type=\"virtio\" and "
+                        "./target/@name=\"org.libguestfs.channel.0\"]",
+                                     xpathCtx);
+  if (xpathObj == NULL) {
+    error (g, _("unable to evaluate XPath expression"));
+    goto cleanup;
+  }
+
+  xmlNodeSetPtr nodes = xpathObj->nodesetval;
+  for (i = 0; i < nodes->nodeNr; ++i) {
+    xmlXPathObjectPtr xppath;
+
+    /* See note in function above. */
+    xpathCtx->node = nodes->nodeTab[i];
+
+    /* The path is in <source path=..> attribute. */
+    xppath = xmlXPathEvalExpression (BAD_CAST "./source/@path", xpathCtx);
+    if (xppath == NULL ||
+        xppath->nodesetval == NULL ||
+        xppath->nodesetval->nodeNr == 0) {
+      xmlXPathFreeObject (xppath);
+      continue;                 /* no type attribute, skip it */
+    }
+    assert (xppath->nodesetval->nodeTab[0]);
+    assert (xppath->nodesetval->nodeTab[0]->type == XML_ATTRIBUTE_NODE);
+    xmlAttrPtr attr = (xmlAttrPtr) xppath->nodesetval->nodeTab[0];
+    path = (char *) xmlNodeListGetString (doc, attr->children, 1);
+    xmlXPathFreeObject (xppath);
+    break;
+  }
+
+  if (path == NULL) {
+    error (g, _("this guest has no libvirt <channel> definition for guestfsd\n"
+                "See ATTACHING TO RUNNING DAEMONS in guestfs(3) for further information."));
+    goto cleanup;
+  }
+
+  /* Got a path. */
+  attach_method = safe_malloc (g, strlen (path) + 5 + 1);
+  strcpy (attach_method, "unix:");
+  strcat (attach_method, path);
+  r = guestfs_set_attach_method (g, attach_method);
 
  cleanup:
-  if (r == -1) guestfs___rollback_cmdline (g, cmdline_pos);
+  free (path);
+  free (attach_method);
+  free (xml);
+  if (xpathObj) xmlXPathFreeObject (xpathObj);
+  if (xpathCtx) xmlXPathFreeContext (xpathCtx);
+  if (doc) xmlFreeDoc (doc);
+
   return r;
 }