[libvirt] [PATCH] virsh edit command
Richard W.M. Jones
rjones at redhat.com
Tue Jul 29 12:27:42 UTC 2008
One thing which is very apparent is that sys admins using libvirt /
virsh have a great deal of difficulty understanding "where the
configuration files have gone" and how to edit them.
This patch adds a "virsh edit <domain>" command which is basically the
equivalent of:
virsh dumpxml dom > /tmp/dom.xml
$EDITOR /tmp/dom.xml && virsh define /tmp/dom.xml
but with much more sanity checking. The editor is $EDITOR or vi, and
it does the right thing if the user doesn't modify the file, or if
another user edits the configuration at the same time.
Rich.
--
Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
-------------- next part --------------
Index: docs/virsh.pod
===================================================================
RCS file: /data/cvs/libvirt/docs/virsh.pod,v
retrieving revision 1.16
diff -u -r1.16 virsh.pod
--- docs/virsh.pod 15 May 2008 06:12:32 -0000 1.16
+++ docs/virsh.pod 29 Jul 2008 12:21:38 -0000
@@ -277,6 +277,19 @@
Output the domain information as an XML dump to stdout, this format can be used by the B<create> command.
+=item B<edit> I<domain-id>
+
+Edit the XML configuration file for a domain.
+
+This is equivalent to:
+ virsh dumpxml domain > domain.xml
+ edit domain.xml
+ virsh define domain.xml
+except that it does some error checking.
+
+The editor used can be supplied by the C<$EDITOR> environment
+variable, or if that is not defined defaults to C<vi>.
+
=item B<migrate> optional I<--live> I<domain-id> I<desturi> I<migrateuri>
Migrate domain to another host. Add --live for live migration. The I<desturi>
Index: src/virsh.c
===================================================================
RCS file: /data/cvs/libvirt/src/virsh.c,v
retrieving revision 1.157
diff -u -r1.157 virsh.c
--- src/virsh.c 22 Jul 2008 16:12:01 -0000 1.157
+++ src/virsh.c 29 Jul 2008 12:21:42 -0000
@@ -5070,6 +5070,179 @@
}
/*
+ * "edit" command
+ */
+static vshCmdInfo info_edit[] = {
+ {"syntax", "edit <domain>"},
+ {"help", gettext_noop("edit XML configuration for a domain")},
+ {"desc", gettext_noop("Edit the XML configuration for a domain.")},
+ {NULL, NULL}
+};
+
+static vshCmdOptDef opts_edit[] = {
+ {"domain", VSH_OT_DATA, VSH_OFLAG_REQ, gettext_noop("domain name, id or uuid")},
+ {NULL, 0, 0, NULL}
+};
+
+static int
+cmdEdit (vshControl *ctl, vshCmd *cmd)
+{
+ int ret = FALSE;
+ virDomainPtr dom = NULL;
+ char *doc = NULL;
+ char *tmp = NULL;
+ int fd = -1;
+ const char *editor;
+ char command[100];
+ int command_ret;
+ char *doc_edited = NULL;
+ struct stat statbuf;
+ char *doc_reread = NULL;
+
+ if (!vshConnectionUsability(ctl, ctl->conn, TRUE))
+ goto cleanup;
+
+ dom = vshCommandOptDomain (ctl, cmd, "domain", NULL);
+ if (dom == NULL)
+ goto cleanup;
+
+ /* Get the XML configuration of the domain. */
+ doc = virDomainGetXMLDesc (dom, 0);
+ if (!doc)
+ goto cleanup;
+
+ /* Create and open the temporary file. */
+ tmp = tempnam (NULL, "virsh");
+ if (!tmp) {
+ vshError(ctl, FALSE,
+ _("tempnam: failed to create temporary file: %s"),
+ strerror (errno));
+ goto cleanup;
+ }
+ fd = open (tmp, O_EXCL|O_CREAT|O_WRONLY, 0600);
+ if (fd == -1) {
+ vshError(ctl, FALSE,
+ _("open: %s: failed to create temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+
+ if (safewrite (fd, doc, strlen (doc)) == -1) {
+ vshError(ctl, FALSE,
+ _("write: %s: failed to create temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+ if (close (fd) == -1) {
+ vshError(ctl, FALSE,
+ _("close: %s: failed to create temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+ fd = -1;
+
+ /* Start the editor. */
+ editor = getenv ("EDITOR");
+ if (!editor) editor = "vi"; /* could be cruel & default to ed(1) here */
+
+ snprintf (command, sizeof command, "%s %s", editor, tmp);
+ command_ret = system (command);
+
+ if (command_ret == -1) {
+ vshError(ctl, FALSE,
+ "%s: %s",
+ command, strerror (errno));
+ goto cleanup;
+ }
+ if (command_ret != WEXITSTATUS (0)) {
+ vshError(ctl, FALSE,
+ _("%s: command exited with non-zero status"), command);
+ goto cleanup;
+ }
+
+ /* Read back the edited XML file. */
+ fd = open (tmp, O_RDONLY);
+ if (fd == -1) {
+ vshError(ctl, FALSE,
+ _("open: %s: failed to read temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+ if (fstat (fd, &statbuf) == -1) {
+ vshError(ctl, FALSE,
+ _("stat: %s: failed to read temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+ doc_edited = malloc (statbuf.st_size + 1);
+ if (!doc_edited) {
+ vshError(ctl, FALSE,
+ _("malloc: failed to allocate memory for file: %s"),
+ strerror (errno));
+ goto cleanup;
+ }
+ doc_edited[statbuf.st_size+1] = '\0';
+ if (saferead (fd, doc_edited, statbuf.st_size) == -1) {
+ vshError(ctl, FALSE,
+ _("read: %s: failed to read temporary file: %s"),
+ tmp, strerror (errno));
+ goto cleanup;
+ }
+ close (fd);
+ fd = -1;
+
+ unlink (tmp);
+ tmp = NULL;
+
+ /* Compare original XML with edited. Has it changed at all? */
+ if (STREQ (doc, doc_edited)) {
+ vshPrint(ctl, _("Domain %s XML configuration not changed.\n"),
+ virDomainGetName (dom));
+ ret = TRUE;
+ goto cleanup;
+ }
+
+ /* Now re-read the domain XML. Did someone else change it while
+ * it was being edited? This also catches problems such as us
+ * losing a connection or the domain going away.
+ */
+ doc_reread = virDomainGetXMLDesc (dom, 0);
+ if (!doc_reread)
+ goto cleanup;
+
+ if (STRNEQ (doc, doc_reread)) {
+ vshError (ctl, FALSE,
+ _("ERROR: the XML configuration was changed by another user"));
+ goto cleanup;
+ }
+
+ /* Everything checks out, so redefine the domain. */
+ virDomainFree (dom);
+ dom = virDomainDefineXML(ctl->conn, doc_edited);
+ if (!dom)
+ goto cleanup;
+
+ vshPrint(ctl, _("Domain %s XML configuration edited.\n"),
+ virDomainGetName(dom));
+
+ ret = TRUE;
+
+ cleanup:
+ if (fd >= 0)
+ close (fd);
+ if (dom)
+ virDomainFree(dom);
+ free (doc);
+ free (doc_edited);
+ if (tmp) {
+ unlink (tmp);
+ free (tmp);
+ }
+
+ return ret;
+}
+
+/*
* "quit" command
*/
static vshCmdInfo info_quit[] = {
@@ -5112,6 +5285,7 @@
{"domblkstat", cmdDomblkstat, opts_domblkstat, info_domblkstat},
{"domifstat", cmdDomIfstat, opts_domifstat, info_domifstat},
{"dumpxml", cmdDumpXML, opts_dumpxml, info_dumpxml},
+ {"edit", cmdEdit, opts_edit, info_edit},
{"freecell", cmdFreecell, opts_freecell, info_freecell},
{"hostname", cmdHostname, NULL, info_hostname},
{"list", cmdList, opts_list, info_list},
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