[libvirt] [PATCH] Add warning message to XML definition files stored on disk

[Laine Stump]

On 04/28/2011 12:34 PM, Michal Privoznik wrote:
> Users often edit XML domain file stored in configuration directory
> thinking of modifying a domain/network/pool/etc. Thus it is wise
> to let them know they are using the wrong way and give them hint.
> ---
>   src/conf/domain_conf.c   |    2 ++
>   src/conf/network_conf.c  |    1 +
>   src/conf/nwfilter_conf.c |    3 +++
>   src/conf/storage_conf.c  |    2 ++
>   src/libvirt_private.syms |    1 +
>   src/util/util.c          |   22 ++++++++++++++++++++++
>   src/util/util.h          |    2 ++
>   7 files changed, 33 insertions(+), 0 deletions(-)
>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 2a681d9..4cd1228 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -8543,6 +8543,7 @@ int virDomainSaveConfig(const char *configDir,
>                                      VIR_DOMAIN_XML_WRITE_FLAGS)))
>           goto cleanup;
>
> +    virSavePrependWarning(&xml);
>       if (virDomainSaveXML(configDir, def, xml))
>           goto cleanup;
>
> @@ -8563,6 +8564,7 @@ int virDomainSaveStatus(virCapsPtr caps,
>       if (!(xml = virDomainObjFormat(caps, obj, flags)))
>           goto cleanup;
>
> +    virSavePrependWarning(&xml);
>       if (virDomainSaveXML(statusDir, obj->def, xml))
>           goto cleanup;
>
> diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
> index 5738757..82f10e6 100644
> --- a/src/conf/network_conf.c
> +++ b/src/conf/network_conf.c
> @@ -959,6 +959,7 @@ int virNetworkSaveConfig(const char *configDir,
>       if (!(xml = virNetworkDefFormat(def)))
>           goto cleanup;
>
> +    virSavePrependWarning(&xml);
>       if (virNetworkSaveXML(configDir, def, xml))
>           goto cleanup;
>
> diff --git a/src/conf/nwfilter_conf.c b/src/conf/nwfilter_conf.c
> index 09dc32b..fcd0b24 100644
> --- a/src/conf/nwfilter_conf.c
> +++ b/src/conf/nwfilter_conf.c
> @@ -2282,6 +2282,7 @@ int virNWFilterSaveConfig(const char *configDir,
>       if (!(xml = virNWFilterDefFormat(def)))
>           goto cleanup;
>
> +    virSavePrependWarning(&xml);
>       if (virNWFilterSaveXML(configDir, def, xml))
>           goto cleanup;
>
> @@ -2635,6 +2636,8 @@ virNWFilterObjSaveDef(virNWFilterDriverStatePtr driver,
>           return -1;
>       }
>
> +    virSavePrependWarning(&xml);
> +
>       if ((fd = open(nwfilter->configFile,
>                      O_WRONLY | O_CREAT | O_TRUNC,
>                      S_IRUSR | S_IWUSR ))<  0) {
> diff --git a/src/conf/storage_conf.c b/src/conf/storage_conf.c
> index 116898d..96aa567 100644
> --- a/src/conf/storage_conf.c
> +++ b/src/conf/storage_conf.c
> @@ -1542,6 +1542,8 @@ virStoragePoolObjSaveDef(virStorageDriverStatePtr driver,
>           return -1;
>       }
>
> +    virSavePrependWarning(&xml);
> +
>       if ((fd = open(pool->configFile,
>                      O_WRONLY | O_CREAT | O_TRUNC,
>                      S_IRUSR | S_IWUSR ))<  0) {
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 1b22be6..f2c005e 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -946,6 +946,7 @@ virRandom;
>   virRandomInitialize;
>   virRun;
>   virRunWithHook;
> +virSavePrependWarning;
>   virSetBlocking;
>   virSetCloseExec;
>   virSetInherit;
> diff --git a/src/util/util.c b/src/util/util.c
> index 1bb0328..c6a4634 100644
> --- a/src/util/util.c
> +++ b/src/util/util.c
> @@ -3204,3 +3204,25 @@ bool virIsDevMapperDevice(const char *devname ATTRIBUTE_UNUSED)
>       return false;
>   }
>   #endif
> +
> +int virSavePrependWarning(char **xml) {
> +    char *retPtr = NULL;
> +    int ret;
> +
> +    ret = virAsprintf(&retPtr, "%s\n%s",
> +                      _("<!--\n\
> +WARNING: THIS IS AN AUTO-GENERATED FILE.  CHANGES TO IT ARE LIKELY TO BE\n\
> +OVERWRITTEN AND LOST.  Changes to xml configurations should be made using virsh\n\
> +edit or other application using the libvirt API.  See:\n\

either s/or other/or another/ or else s/application/applications/


> +\n\
> +http://wiki.libvirt.org/wiki/index.php?title=FAQ#Where_are_VM_config_files_stored.3F_How_do_I_edit_a_VM.27s_XML_config.3F\n\
> +-->\n"),

Can this URL change if the wiki is edited? Do we maybe want to put this 
info in a less modifiable place? (Dunno, just asking.)

> +                      *xml);
> +
> +    if (ret<  0)
> +        return ret;
> +
> +    VIR_FREE(*xml);

I'm not really comfortable that it requires the caller to initialize to 
0. But that may be just me - anyone else have an opinion?

> +    *xml = retPtr;
> +    return ret;
> +}
> diff --git a/src/util/util.h b/src/util/util.h
> index d320c40..a6a91de 100644
> --- a/src/util/util.h
> +++ b/src/util/util.h
> @@ -299,4 +299,6 @@ int virBuildPathInternal(char **path, ...) ATTRIBUTE_SENTINEL;
>   char *virTimestamp(void);
>
>   bool virIsDevMapperDevice(const char *devname) ATTRIBUTE_NONNULL(1);
> +
> +int virSavePrependWarning(char **xml);
>   #endif /* __VIR_UTIL_H__ */