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

[Michal Privoznik]

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\
+\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"),
+                      *xml);
+
+    if (ret < 0)
+        return ret;
+
+    VIR_FREE(*xml);
+    *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__ */
-- 
1.7.4.4