X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=src%2Fvirt.c;h=a95b0290037a4b83f6ecf094ffdf4565323bed4e;hb=99ec97dcdfaf242ba0683a230ba51e4a87f7458b;hp=2c6be3c6a2392ab8242d1f4cee9c0d1445844385;hpb=4838ec3326d2970e6afe3cde6b368aeae840b969;p=libguestfs.git

diff --git a/src/virt.c b/src/virt.c
index 2c6be3c..a95b029 100644
--- a/src/virt.c
+++ b/src/virt.c
@@ -53,12 +53,22 @@ 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;
+#define GUESTFS___ADD_LIBVIRT_DOM_READONLYDISK_BITMASK (UINT64_C(1)<<3)
+  const char *readonlydisk;
 };
 
 static int guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom, const struct guestfs___add_libvirt_dom_argv *optargs);
@@ -73,6 +83,9 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
   int r = -1;
   const char *libvirturi;
   int readonly;
+  int live;
+  int allowuuid;
+  const char *readonlydisk;
   const char *iface;
   struct guestfs___add_libvirt_dom_argv optargs2 = { .bitmask = 0 };
 
@@ -82,6 +95,17 @@ 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;
+  readonlydisk = optargs->bitmask & GUESTFS_ADD_DOMAIN_READONLYDISK_BITMASK
+               ? optargs->readonlydisk : NULL;
+
+  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 +116,20 @@ 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 +145,14 @@ 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;
+  }
+  if (readonlydisk) {
+    optargs2.bitmask |= GUESTFS___ADD_LIBVIRT_DOM_READONLYDISK_BITMASK;
+    optargs2.readonlydisk = readonlydisk;
+  }
 
   r = guestfs___add_libvirt_dom (g, dom, &optargs2);
 
@@ -131,6 +176,7 @@ guestfs___for_each_disk (guestfs_h *g,
                          virDomainPtr dom,
                          int (*f) (guestfs_h *g,
                                    const char *filename, const char *format,
+                                   int readonly,
                                    void *data),
                          void *data)
 {
@@ -196,8 +242,8 @@ 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;
 
@@ -248,9 +294,20 @@ guestfs___for_each_disk (guestfs_h *g,
       format = (char *) xmlNodeListGetString (doc, attr->children, 1);
     }
 
+    /* Get the <readonly/> flag. */
+    xmlXPathObjectPtr xpreadonly;
+
+    xpathCtx->node = nodes->nodeTab[i];
+    xpreadonly = xmlXPathEvalExpression (BAD_CAST "./readonly", xpathCtx);
+    int readonly = 0;
+    if (xpreadonly != NULL &&
+        xpreadonly->nodesetval &&
+        xpreadonly->nodesetval->nodeNr > 0)
+      readonly = 1;
+
     int t;
     if (f)
-      t = f (g, filename, format, data);
+      t = f (g, filename, format, readonly, data);
     else
       t = 0;
 
@@ -258,6 +315,7 @@ guestfs___for_each_disk (guestfs_h *g,
     xmlFree (format);
     xmlXPathFreeObject (xpfilename);
     xmlXPathFreeObject (xpformat);
+    xmlXPathFreeObject (xpreadonly);
 
     if (t == -1)
       goto cleanup;
@@ -282,67 +340,262 @@ 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;
+/* This was proposed as an external API, but it's not quite baked yet. */
 
-  if (format) {
-    optargs->bitmask |= GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
-    optargs->format = format;
-  } else
-    optargs->bitmask &= ~GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
+static int add_disk (guestfs_h *g, const char *filename, const char *format, int readonly, void *data);
+static int connect_live (guestfs_h *g, virDomainPtr dom);
 
-  return guestfs__add_drive_opts (g, filename, optargs);
-}
+enum readonlydisk {
+  readonlydisk_error,
+  readonlydisk_read,
+  readonlydisk_write,
+  readonlydisk_ignore,
+};
+
+struct add_disk_data {
+  int readonly;
+  enum readonlydisk readonlydisk;
+  /* Other args to pass through to add_drive_opts. */
+  struct guestfs_add_drive_opts_argv optargs;
+};
 
-/* 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;
+  /* Default for back-compat reasons: */
+  enum readonlydisk readonlydisk = readonlydisk_write;
 
-  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 ((optargs->bitmask & GUESTFS___ADD_LIBVIRT_DOM_READONLYDISK_BITMASK)) {
+    if (STREQ (optargs->readonlydisk, "error"))
+      readonlydisk = readonlydisk_error;
+    else if (STREQ (optargs->readonlydisk, "read"))
+      readonlydisk = readonlydisk_read;
+    else if (STREQ (optargs->readonlydisk, "write"))
+      readonlydisk = readonlydisk_write;
+    else if (STREQ (optargs->readonlydisk, "ignore"))
+      readonlydisk = readonlydisk_ignore;
+    else {
+      error (g, _("unknown readonlydisk parameter"));
+      return -1;
+    }
+  }
+
+  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;
     }
   }
 
   /* Add the disks. */
-  struct guestfs_add_drive_opts_argv optargs2 = { .bitmask = 0 };
-  if (readonly) {
-    optargs2.bitmask |= GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK;
-    optargs2.readonly = readonly;
-  }
+  struct add_disk_data data;
+  data.optargs.bitmask = 0;
+  data.readonly = readonly;
+  data.readonlydisk = readonlydisk;
   if (iface) {
-    optargs2.bitmask |= GUESTFS_ADD_DRIVE_OPTS_IFACE_BITMASK;
-    optargs2.iface = iface;
+    data.optargs.bitmask |= GUESTFS_ADD_DRIVE_OPTS_IFACE_BITMASK;
+    data.optargs.iface = iface;
   }
 
-  r = guestfs___for_each_disk (g, dom, add_disk, &optargs2);
+  /* Checkpoint the command line around the operation so that either
+   * all disks are added or none are added.
+   */
+  struct drive **cp = guestfs___checkpoint_drives (g);
+  r = guestfs___for_each_disk (g, dom, add_disk, &data);
+  if (r == -1)
+    guestfs___rollback_drives (g, cp);
+
+  return r;
+}
+
+static int
+add_disk (guestfs_h *g,
+          const char *filename, const char *format, int readonly_in_xml,
+          void *datavp)
+{
+  struct add_disk_data *data = datavp;
+  /* Copy whole struct so we can make local changes: */
+  struct guestfs_add_drive_opts_argv optargs = data->optargs;
+  int readonly, error = 0, skip = 0;
+
+  if (readonly_in_xml) {        /* <readonly/> appears in the XML */
+    if (data->readonly) {       /* asked to add disk read-only */
+      switch (data->readonlydisk) {
+      case readonlydisk_error: readonly = 1; break;
+      case readonlydisk_read: readonly = 1; break;
+      case readonlydisk_write: readonly = 1; break;
+      case readonlydisk_ignore: skip = 1; break;
+      default: abort ();
+      }
+    } else {                    /* asked to add disk for read/write */
+      switch (data->readonlydisk) {
+      case readonlydisk_error: error = 1; break;
+      case readonlydisk_read: readonly = 1; break;
+      case readonlydisk_write: readonly = 0; break;
+      case readonlydisk_ignore: skip = 1; break;
+      default: abort ();
+      }
+    }
+  } else                        /* no <readonly/> in XML */
+    readonly = data->readonly;
+
+  if (skip)
+    return 0;
+
+  if (error) {
+    error (g, _("%s: disk is marked <readonly/> in libvirt XML, and readonlydisk was set to \"error\""),
+           filename);
+    return -1;
+  }
+
+  optargs.bitmask |= GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK;
+  optargs.readonly = readonly;
+
+  if (format) {
+    optargs.bitmask |= GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK;
+    optargs.format = format;
+  }
+
+  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;
 }