From cfd9513a54778e1ade82dc1eb351ea32416938a8 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Fri, 28 Jan 2011 13:19:52 +0000 Subject: [PATCH] Add guestfs_add_domain 'live' flag. This optional flag controls whether this API call will try to connect to a running virtual machine 'guestfsd' process. If the flag is given and the virtual machine is running, then the libvirt XML is parsed looking for a suitable element, and 'guestfs_set_attach_method' is called with the corresponding virtio-serial socket path. --- fish/fish.c | 2 +- generator/generator_actions.ml | 18 +++- src/virt.c | 192 +++++++++++++++++++++++++++++++++++------ 3 files changed, 183 insertions(+), 29 deletions(-) diff --git a/fish/fish.c b/fish/fish.c index 10f645f..eb7c8fe 100644 --- a/fish/fish.c +++ b/fish/fish.c @@ -1,5 +1,5 @@ /* guestfish - the filesystem interactive shell - * Copyright (C) 2009-2010 Red Hat Inc. + * Copyright (C) 2009-2011 Red Hat Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml index a2e7467..192df77 100644 --- a/generator/generator_actions.ml +++ b/generator/generator_actions.ml @@ -1074,7 +1074,7 @@ Please read L for more details."); This returns the internal QEMU command line. 'debug' commands are not part of the formal API and can be removed or changed at any time."); - ("add_domain", (RInt "nrdisks", [String "dom"], [String "libvirturi"; Bool "readonly"; String "iface"]), -1, [FishAlias "domain"], + ("add_domain", (RInt "nrdisks", [String "dom"], [String "libvirturi"; Bool "readonly"; String "iface"; Bool "live"]), -1, [FishAlias "domain"], [], "add the disk(s) from a named libvirt domain", "\ @@ -1101,12 +1101,18 @@ we connect to the default libvirt URI (or one set through an environment variable, see the libvirt documentation for full details). +The optional C flag controls whether this call will try +to connect to a running virtual machine C process if +it sees a suitable EchannelE element in the libvirt +XML definition. The default (if the flag is omitted) is never +to try. + The other optional parameters are passed directly through to C."); (* This interface is not quite baked yet. -- RWMJ 2010-11-11 - ("add_libvirt_dom", (RInt "nrdisks", [Pointer ("virDomainPtr", "dom")], [Bool "readonly"; String "iface"]), -1, [NotInFish], + ("add_libvirt_dom", (RInt "nrdisks", [Pointer ("virDomainPtr", "dom")], [Bool "readonly"; String "iface"; Bool "live"]), -1, [NotInFish], [], "add the disk(s) from a libvirt domain", "\ @@ -1129,7 +1135,13 @@ from a remote libvirt connection (see L) will fail unless those disks are accessible via the same device path locally too. -The optional parameters are passed directly through to +The optional C flag controls whether this call will try +to connect to a running virtual machine C process if +it sees a suitable EchannelE element in the libvirt +XML definition. The default (if the flag is omitted) is never +to try. + +The other optional parameters are passed directly through to C."); *) diff --git a/src/virt.c b/src/virt.c index 9f84908..4b66cc8 100644 --- a/src/virt.c +++ b/src/virt.c @@ -59,6 +59,8 @@ struct guestfs___add_libvirt_dom_argv { 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 +75,7 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name, int r = -1; const char *libvirturi; int readonly; + int live; const char *iface; struct guestfs___add_libvirt_dom_argv optargs2 = { .bitmask = 0 }; @@ -82,6 +85,13 @@ 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; + + if (live && readonly) { + error (g, _("you cannot set both live and readonly flags")); + return -1; + } /* Connect to libvirt, find the domain. */ conn = virConnectOpenReadOnly (libvirturi); @@ -108,6 +118,10 @@ 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); @@ -282,49 +296,63 @@ 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; + int r; + int readonly; + const char *iface; + int live; - cmdline_pos = guestfs___checkpoint_cmdline (g); - - 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 +367,124 @@ 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 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 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 definition for guestfsd")); + 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; } -- 1.8.3.1