Hugh Brock wrote:

virDomainDefineXML should overwrite an existing inactive domain config if it finds one; it does this successfully for later (post 3.0.3) xen versions. However on xen 3.0.3 overwriting an existing config would fail with a name conflict. This patch allows the overwrite, removing the prior config from the config hashes.

If someone more familiar than I with libvirt error handling and style could look at this and tell me if I've done something horribly wrong, I'd appreciate it.

Signed-off-by: Hugh Brock <hbrock@redhat.com>

Thinking aloud and trying to untangle the various hashes used ...

Index: src/xm_internal.c =================================================================== RCS file: /data/cvs/libvirt/src/xm_internal.c,v retrieving revision 1.23 diff -u -r1.23 xm_internal.c --- src/xm_internal.c 4 Apr 2007 14:19:49 -0000 1.23 +++ src/xm_internal.c 1 May 2007 17:23:05 -0000 @@ -2072,7 +2072,9 @@ */ virDomainPtr xenXMDomainDefineXML(virConnectPtr conn, const char *xml) { virDomainPtr ret; + virDomainPtr olddomain; char filename[PATH_MAX]; + const char * oldfilename; unsigned char uuid[VIR_UUID_BUFLEN]; virConfPtr conf = NULL; xenXMConfCachePtr entry = NULL; @@ -2103,8 +2105,44 @@ }

if (virHashLookup(nameConfigMap, value->str)) { - xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "domain with name already exists"); - goto error; + /* domain exists, we will overwrite it */ + + if (!(oldfilename = (char *)virHashLookup(nameConfigMap, value->str))) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't retrieve config filename for domain to overwrite"); + goto error; + }

So get the filename from the nameConfigMap. Looks OK, although you could have also got the filename from configDir ++ "/" ++ value->str, but no matter.

+ if (!(entry = virHashLookup(configCache, oldfilename))) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't retrieve config entry for domain to overwrite"); + goto error; + }

Get the xenXMConfCache object from the configCache keyed on filename. Looks OK. Despite the name, configCache isn't literally a cache. Rather it's a list of filename -> config entries for everything under /etc/xen.

+ if (xenXMConfigGetUUID(entry->conf, "uuid", uuid) < 0) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "uuid config parameter is missing"); + goto error; + }

Get the UUID from the config file.

+ if (!(olddomain = virGetDomain(conn, value->str, uuid))) + goto error;

Get the old domain, given name & UUID.

+ if (olddomain->id != -1) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't overwrite an active domain"); + goto error; + } + + /* Remove the name -> filename mapping */ + if (virHashRemoveEntry(nameConfigMap, value->str, NULL) < 0) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "failed to remove old domain from config map"); + goto error; + }

Remove the old mapping in nameConfigMap.

+ /* Remove the config record itself */ + if (virHashRemoveEntry(configCache, oldfilename, xenXMConfigFree) < 0) { + xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "failed to remove old domain from config map"); + goto error; + }

Remove the configCache entry.

+ entry = NULL; }

if ((strlen(configDir) + 1 + strlen(value->str) + 1) > PATH_MAX) {

and then drop through to virConfWriteFile which will blindly overwrite the file. Looks A-OK to me! Rich. -- Emerging Technologies, Red Hat http://et.redhat.com/~rjones/ 64 Baker Street, London, W1U 7DF Mobile: +44 7866 314 421 Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Directors: Michael Cunningham (USA), Charlie Peters (USA) and David Owens (Ireland)