Re: [Libguestfs] [PATCH 5/7] New APIs: add-domain and add-libvirt-dom.

diff --git a/src/guestfs.h b/src/guestfs.h index 0f4f9fd..be7398a 100644 --- a/src/guestfs.h +++ b/src/guestfs.h @@ -79,6 +79,11 @@ extern void guestfs_set_private (guestfs_h *g, const char *key, void *data); extern void *guestfs_get_private (guestfs_h *g, const char *key); /*--- Structures and actions ---*/ + +/* Hack to avoid needing to include <libvirt.h> */ +typedef struct _virDomain virDomain; +typedef virDomain *virDomainPtr; + #include <rpc/types.h> #include <rpc/xdr.h> #include <guestfs-structs.h>

diff --git a/src/virt.c b/src/virt.c new file mode 100644 index 0000000..5816f61 --- /dev/null +++ b/src/virt.c @@ -0,0 +1,287 @@ +/* libguestfs + * Copyright (C) 2010 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> + +#ifdef HAVE_LIBVIRT +#include <libvirt/libvirt.h> +#include <libvirt/virterror.h> +#endif + +#ifdef HAVE_LIBXML2 +#include <libxml/xpath.h> +#include <libxml/parser.h> +#include <libxml/tree.h> +#endif + +#include "guestfs.h" +#include "guestfs-internal.h" +#include "guestfs-internal-actions.h" +#include "guestfs_protocol.h" + +#if defined(HAVE_LIBVIRT) && defined(HAVE_LIBXML2) + +static void init_libxml2 (void) __attribute__((constructor)); + +static void +init_libxml2 (void) +{ + /* I am told that you don't really need to call virInitialize ... */ + + xmlInitParser (); + LIBXML_TEST_VERSION; +} + +int +guestfs__add_domain (guestfs_h *g, const char *domain_name, + const struct guestfs_add_domain_argv *optargs) +{ + virErrorPtr err; + virConnectPtr conn = NULL; + virDomainPtr dom = NULL; + int r = -1; + const char *libvirturi; + int readonly; + const char *iface; + struct guestfs_add_libvirt_dom_argv optargs2 = { .bitmask = 0 }; + + libvirturi = optargs->bitmask & GUESTFS_ADD_DOMAIN_LIBVIRTURI_BITMASK + ? optargs->libvirturi : NULL; + readonly = optargs->bitmask & GUESTFS_ADD_DOMAIN_READONLY_BITMASK + ? optargs->readonly : 0; + iface = optargs->bitmask & GUESTFS_ADD_DOMAIN_IFACE_BITMASK + ? optargs->iface : NULL; + + /* Connect to libvirt, find the domain. */ + conn = virConnectOpenReadOnly (libvirturi); + if (!conn) { + err = virGetLastError (); + error (g, _("could not connect to libvirt (code %d, domain %d): %s"), + err->code, err->domain, err->message); + goto cleanup; + } + + dom = virDomainLookupByName (conn, domain_name); + if (!dom) { + err = virConnGetLastError (conn); + error (g, _("no libvirt domain called '%s': %s"), + domain_name, err->message); + goto cleanup; + } + + if (readonly) { + optargs2.bitmask |= GUESTFS_ADD_LIBVIRT_DOM_READONLY_BITMASK; + optargs2.readonly = readonly; + } + if (iface) { + optargs2.bitmask |= GUESTFS_ADD_LIBVIRT_DOM_IFACE_BITMASK; + optargs2.iface = iface; + } + + r = guestfs__add_libvirt_dom (g, dom, &optargs2); + + cleanup: + if (dom) virDomainFree (dom); + if (conn) virConnectClose (conn); + + return r; +} + +int +guestfs__add_libvirt_dom (guestfs_h *g, virDomainPtr dom, + const struct guestfs_add_libvirt_dom_argv *optargs) +{ + int r = -1, nr_added = 0, i; + virErrorPtr err; + virConnectPtr conn = virDomainGetConnect (dom); + xmlDocPtr doc = NULL; + xmlXPathContextPtr xpathCtx = NULL; + xmlXPathObjectPtr xpathObj = NULL; + char *xml = NULL; + int readonly; + const char *iface; + int cmdline_pos; + + cmdline_pos = guestfs___checkpoint_cmdline (g); + + readonly = optargs->bitmask & GUESTFS_ADD_LIBVIRT_DOM_READONLY_BITMASK + ? optargs->readonly : 0; + iface = optargs->bitmask & GUESTFS_ADD_LIBVIRT_DOM_IFACE_BITMASK + ? optargs->iface : NULL; + + if (!readonly) { + virDomainInfo info; + if (virDomainGetInfo (dom, &info) == -1) { + err = virConnGetLastError (conn); + error (g, _("error getting domain info: %s"), err->message); + goto cleanup; + } + 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; + } + } + + /* Domain XML. */ + xml = virDomainGetXMLDesc (dom, 0); + + if (!xml) { + err = virConnGetLastError (conn); + error (g, _("error reading libvirt XML information: %s"), + err->message); + goto cleanup; + } + + /* Now the horrible task of parsing out the fields we need from the XML. + * http://www.xmlsoft.org/examples/xpath1.c + */ + 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 <disk> nodes. */ + xpathObj = xmlXPathEvalExpression (BAD_CAST "//devices/disk", 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 xpfilename; + xmlXPathObjectPtr xpformat; + + /* Change the context to the current <disk> node. + * DV advises to reset this before each search since older versions of + * libxml2 might overwrite it. + */ + xpathCtx->node = nodes->nodeTab[i]; + + /* Filename can be in <source dev=..> or <source file=..> attribute. */ + xpfilename = xmlXPathEvalExpression (BAD_CAST "./source/@dev", xpathCtx); + if (xpfilename == NULL || + xpfilename->nodesetval == NULL || + xpfilename->nodesetval->nodeNr == 0) { + xmlXPathFreeObject (xpfilename); + xpathCtx->node = nodes->nodeTab[i]; + xpfilename = xmlXPathEvalExpression (BAD_CAST "./source/@file", xpathCtx); + if (xpfilename == NULL || + xpfilename->nodesetval == NULL || + xpfilename->nodesetval->nodeNr == 0) { + xmlXPathFreeObject (xpfilename); + continue; /* disk filename not found, skip this */ + } + } + + assert (xpfilename->nodesetval->nodeTab[0]); + assert (xpfilename->nodesetval->nodeTab[0]->type == XML_ATTRIBUTE_NODE); + xmlAttrPtr attr = (xmlAttrPtr) xpfilename->nodesetval->nodeTab[0]; + char *filename = (char *) xmlNodeListGetString (doc, attr->children, 1); + + /* Get the disk format (may not be set). */ + xpathCtx->node = nodes->nodeTab[i]; + xpformat = xmlXPathEvalExpression (BAD_CAST "./driver/@type", xpathCtx); + char *format = NULL; + if (xpformat != NULL && + xpformat->nodesetval && + xpformat->nodesetval->nodeNr > 0) { + assert (xpformat->nodesetval->nodeTab[0]); + assert (xpformat->nodesetval->nodeTab[0]->type == XML_ATTRIBUTE_NODE); + attr = (xmlAttrPtr) xpformat->nodesetval->nodeTab[0]; + format = (char *) xmlNodeListGetString (doc, attr->children, 1); + } + + /* Add the disk, with optional format. */ + struct guestfs_add_drive_opts_argv optargs2 = { .bitmask = 0 }; + if (readonly) { + optargs2.bitmask |= GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK; + optargs2.readonly = readonly; + } + if (format) { + optargs2.bitmask |= GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK; + optargs2.format = format; + } + if (iface) { + optargs2.bitmask |= GUESTFS_ADD_DRIVE_OPTS_IFACE_BITMASK; + optargs2.iface = iface; + } + + int t = guestfs__add_drive_opts (g, filename, &optargs2); + + xmlFree (filename); + xmlFree (format); + xmlXPathFreeObject (xpfilename); + xmlXPathFreeObject (xpformat); + + if (t == -1) + goto cleanup; + + nr_added++; + } + + if (nr_added == 0) { + error (g, _("libvirt domain has no disks")); + goto cleanup; + } + + /* Successful. */ + r = nr_added; + + cleanup: + if (r == -1) guestfs___rollback_cmdline (g, cmdline_pos); + free (xml); + if (xpathObj) xmlXPathFreeObject (xpathObj); + if (xpathCtx) xmlXPathFreeContext (xpathCtx); + if (doc) xmlFreeDoc (doc); + + return r; +} + +#else /* no libvirt or libxml2 at compile time */ + +#define NOT_IMPL(r) \ + error (g, _("add-domain APIs not available since this version of libguestfs was compiled without libvirt or libxml2")); \ + return r + +int +guestfs__add_domain (guestfs_h *g, const char *dom, + const struct guestfs_add_domain_argv *optargs) +{ + NOT_IMPL(-1); +} + +int +guestfs__add_libvirt_dom (guestfs_h *g, virDomainPtr dom, + const struct guestfs_add_libvirt_dom_argv *optargs) +{ + NOT_IMPL(-1); +} + +#endif /* no libvirt or libxml2 at compile time */